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Sample records for hcci combustion characteristics

  1. EMISSION AND COMBUSTION CHARACTERISTICS OF DIFFERENT FUELS IN A HCCI ENGINE

    Directory of Open Access Journals (Sweden)

    S. Sendilvelan

    2011-06-01

    Full Text Available Different intake valve timings and fuel injection amounts were tested in order to identify their effects on exhaust emissions and combustion characteristics using variable valve actuation (VVA in a Homogeneous Charge Compression Ignition (HCCI engine. The HCCI engine is a promising concept for future automobile engines and stationary power plants. The two-stage ignition process in a HCCI engine creates advanced ignition and stratified combustion, which makes the ignition timing and combustion rate controllable. Meanwhile, the periphery of the fuel-rich zone leads to fierce burning, which results in slightly high NOx emissions. The experiments were conducted in a modified single cylinder water-cooled diesel engine. In this experiment we use diesel, bio-diesel (Jatropha and gasoline as the fuel at different mixing ratios. HCCI has advantages in high thermal efficiency and low emissions and could possibly become a promising combustion method in internal combustion engines.

  2. Establishment of Combustion Model for Isooctane HCCI Marine Diesel Engine and Research on the Combustion Characteristic

    Directory of Open Access Journals (Sweden)

    Li Biao

    2016-01-01

    Full Text Available The homogeneous charge compression ignition (HCCI combustion mode applied in marine diesel engine is expected to be one of alternative technologies to decrease nitrogen oxide (NOX emission and improve energy utilization rate. Applying the chemical-looping combustion (CLC mechanism inside the cylinder, a numerical study on the HCCI combustion process is performed taking a marine diesel engine as application object. The characteristic feature of combustion process is displayed. On this basis, the formation and emission of NOX are analyzed and discussed. The results indicate that the HCCI combustion mode always exhibit two combustion releasing heats: low-temperature reaction and high-temperature reaction. The combustion phase is divided into low-temperature reaction zone, high-temperature reaction zone and negative temperature coefficient (NTC zone. The operating conditions of the high compression ratio, high intake air temperature, low inlet pressure and small excess air coefficient would cause the high in-cylinder pressure which often leads engine detonation. The low compression ratio, low intake air temperature and big excess air coefficient would cause the low combustor temperature which is conducive to reduce NOX emissions. These technological means and operating conditions are expected to meet the NOX emissions limits in MARPOL73/78 Convention-Annex VI Amendment.

  3. EXPERIMENTAL INVESTIGATION OF COMBUSTION, PERFORMANCE AND EMISSION CHARACTERISTICS OF DI DIESEL ENGINE UNDER HCCI MODE WITH POROUS MEDIUM COMBUSTION

    Directory of Open Access Journals (Sweden)

    C KANNAN

    2010-08-01

    Full Text Available In recent times, homogeneous combustion has been a proven technology to attain high efficient and low emission engines. Homogenous Charge Compression Ignition (HCCI engines are able to have efficiencies as high as Compression Ignition, Direct Injection (CIDI engines, while producing ultra-low emissions of nitrogen oxides (NOx and particulate matter (PM.HCCI combustion is achieved by controlling the temperature, pressure and composition of the fuel-air mixture so that it spontaneously gets ignited in the combustion chamber. Numeroustechniques such as Variable Exhaust Gas Recirculation (VEGR, ariable Compression Ratio (VCR and Variable Valve Timing (VVT have been proposed to control the homogeneous combustion inside the engine cylinder. Even though these techniques are attractive and having good time response, they are too expensive to afford. This paper investigates the performance, combustion and emission characteristics of a Direct Injection (DI diesel engine under HCCI mode which is established through an effective and affordable technique called Porous Medium Combustion (PMC.

  4. Simulation Analysis of Combustion Parameters and Emission Characteristics of CNG Fueled HCCI Engine

    Directory of Open Access Journals (Sweden)

    P. M. Diaz

    2013-01-01

    Full Text Available The naturally aspirated compressed natural gas (CNG fueled homogeneous charge compression ignition (HCCI engine operation region is narrow between heavy knock at rich air-fuel mixture side and misfire at the lean air-fuel mixture side. However, high activation energy is needed to attain autoignition temperature of CNG fueled HCCI engine. This paper seeks to provide guidance in overcoming challenges of CNG fueled HCCI engine by using CHEMKIN. It is used to investigate the fundamental characteristics of the homogeneous charge compression ignition combustion process for different air-fuel mixture inlet temperature, relative air-fuel ratio of 2.5, and with hemispherical bowl types of combustion chambers. The variation of various properties like the peak cylinder pressure, peak cylinder temperature, CO emission, NO emission, soot emission, and HC emission are studied. It is necessary to develop new combustion models to simulate and predict all parameters with high accuracy.

  5. EXPERIMENTAL INVESTIGATION OF COMBUSTION, PERFORMANCE AND EMISSION CHARACTERISTICS OF DI DIESEL ENGINE UNDER HCCI MODE WITH POROUS MEDIUM COMBUSTION

    OpenAIRE

    Kannan, C.; P TAMILPORAI

    2010-01-01

    In recent times, homogeneous combustion has been a proven technology to attain high efficient and low emission engines. Homogenous Charge Compression Ignition (HCCI) engines are able to have efficiencies as high as Compression Ignition, Direct Injection (CIDI) engines, while producing ultra-low emissions of nitrogen oxides (NOx) and particulate matter (PM).HCCI combustion is achieved by controlling the temperature, pressure and composition of the fuel-air mixture so that it spontaneously gets...

  6. On the influence of singlet oxygen molecules on characteristics of HCCI combustion: A numerical study

    Science.gov (United States)

    Starik, A. M.; Kozlov, V. E.; Titova, N. S.

    2013-08-01

    Mechanisms of homogeneous charge compression ignition (HCCI) combustion enhancement are investigated numerically when excited O2(a 1Δg) molecules are produced at different points in the compression stroke. The analysis is conducted with the use of an extended kinetic model involving the submechanism of nitric oxide formation in the presence of singlet oxygen O2(a 1Δg) or O2(b 1Σg +) molecules in the methane-air mixture. It is demonstrated that the abundance of excited O2(a 1Δg) molecules in the mixture even in a small amounts intensifies the ignition and combustion and allows one to control the ignition event in the HCCI engine. Such a method of energy supply in the HCCI engine is much more effective in advancement of combustion timing than mere heating of the mixture, because it leads to acceleration of the chain-branching mechanism. The excitation of O2 molecules to the a 1Δg electronic state makes it possible to organise the successful combustion in the cylinder at diminished initial temperature of the mixture and increase the effective energy released during HCCI combustion. The advance in the value of this energy is much higher than the energy needed for the excitation of oxygen molecules. Moreover, in this case, the output concentration of NO and CO can be reduced significantly.

  7. Characteristics and energy distribution of modulated multi-pulse injection modes based diesel HCCI combustion and their effects on engine thermal efficiency and emissions

    Institute of Scientific and Technical Information of China (English)

    LIU Bin; SU Wanhua; WANG Hui; HUANG Haozhong

    2007-01-01

    Cycle fuel energy distribution and combustion characteristics of early in-cylinder diesel homogenous charge compression ignition (HCCI) combustion organized by modulated multi-pulse injection modes are studied by the engine test.It is found that heat loss due to unburned fuel droplets and CO emission can be decreased effectively by injection mode regulation,and thermal efficiency can be potentially increased by 4%-12%.From the analyses of combustion process,it is also found that diesel HCCI combustion is a process with a finite reaction rate and is very sensitive to injection timing and injection mode.At injection timing of-90℃A ATDC,extra low NOx emissions can be obtained along with high thermal efficiency.

  8. Fuel design real-time to control HCCI combustion

    Institute of Scientific and Technical Information of China (English)

    HOU Yuchun; HUANG Zhen; LU Xingcai; FANG Junhuan; ZU Linlin

    2006-01-01

    In order to achieve lower emissions and extensive load in the homogeneous charge compression ignition (HCCI) engine system, a novel fuel design concept that high-octane number fuel and high-cetane number fuel are mixed real-time to control HCCI combustion is proposed in this study. HCCI combustion fueled with iso-octane/n-heptane mixtures controlled real-time on a single-cylinder HCCI combustion engine is studied. The test results show that the equivalence ratio of n-heptane in mixtures decides ignition and controls the combustion phase of HCCI combustion. The addition of iso-octane extends knocking limit in equivalence ratio somewhat,but knocking occurrence mainly depends on the total concentration of mixture. Although operating range in equivalence ratio becomes narrow with the increasing proportion of iso-octane, the maximum load of HCCI combustion fueled with iso-octane/n-heptane mixtures controlled real-time is increased about 80% more than that of pure n-heptane. When iso-octane/n-heptane mixtures are controlled in optimized method, it is proved that the load of HCCI combustion can be fully extended and emissions can be decreased remarkably, while at the same time the higher indicated thermal efficiencies are obtained over the extensive operation range.

  9. Control Strategies for HCCI Mixed-Mode Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Robert M [ORNL; Edwards, Kevin Dean [ORNL

    2010-03-01

    Delphi Automotive Systems and ORNL established this CRADA to expand the operational range of Homogenous Charge Compression Ignition (HCCI) mixed-mode combustion for gasoline en-gines. ORNL has extensive experience in the analysis, interpretation, and control of dynamic engine phenomena, and Delphi has extensive knowledge and experience in powertrain compo-nents and subsystems. The partnership of these knowledge bases was important to address criti-cal barriers associated with the realistic implementation of HCCI and enabling clean, efficient operation for the next generation of transportation engines. The foundation of this CRADA was established through the analysis of spark-assisted HCCI data from a single-cylinder research engine. This data was used to (1) establish a conceptual kinetic model to better understand and predict the development of combustion instabilities, (2) develop a low-order model framework suitable for real-time controls, and (3) provide guidance in the initial definition of engine valve strategies for achieving HCCI operation. The next phase focused on the development of a new combustion metric for real-time characterization of the combustion process. Rapid feedback on the state of the combustion process is critical to high-speed decision making for predictive control. Simultaneous to the modeling/analysis studies, Delphi was focused on the development of engine hardware and the engine management system. This included custom Delphi hardware and control systems allowing for flexible control of the valvetrain sys-tem to enable HCCI operation. The final phase of this CRADA included the demonstration of conventional and spark assisted HCCI on the multi-cylinder engine as well as the characterization of combustion instabilities, which govern the operational boundaries of this mode of combustion. ORNL and Delphi maintained strong collaboration throughout this project. Meetings were held on a bi-weekly basis with additional reports, presentation, and

  10. Optical Study of Flow and Combustion in an HCCI Engine with Negative Valve Overlap

    Science.gov (United States)

    Wilson, Trevor S.; Xu, Hongming; Richardson, Steve; Wyszynski, Miroslaw L.; Megaritis, Thanos

    2006-07-01

    One of the most widely used methods to enable Homogeneous Charge Compression Ignition (HCCI) combustion is using negative valve overlapping to trap a sufficient quantity of hot residual gas. The characteristics of air motion with specially designed valve events having reduced valve lift and durations associated with HCCI engines and their effect on subsequent combustion are not yet fully understood. In addition, the ignition process and combustion development in such engines are very different from those in conventional spark-ignition or diesel compression ignition engines. Very little data has been reported concerning optical diagnostics of the flow and combustion in the engine using negative valve overlapping. This paper presents an experimental investigation into the in-cylinder flow characteristics and combustion development in an optical engine operating in HCCI combustion mode. PIV measurements have been taken under motored engine conditions to provide a quantitative flow characterisation of negative valve overlap in-cylinder flows. The ignition and combustion process was imaged using a high resolution charge coupled device (CCD) camera and the combustion imaging data was supplemented by simultaneously recorded in-cylinder pressure data which assisted the analysis of the images. It is found that the flow characteristics with negative valve overlapping are less stable and more valve event driven than typical spark ignition in-cylinder flows, while the combustion initiation locations are not uniformly distributed.

  11. Maximizing Power Output in Homogeneous Charge Compression Ignition (HCCI) Engines and Enabling Effective Control of Combustion Timing

    Science.gov (United States)

    Saxena, Samveg

    Homogeneous Charge Compression Ignition (HCCI) engines are one of the most promising engine technologies for the future of energy conversion from clean, efficient combustion. HCCI engines allow high efficiency and lower CO2 emission through the use of high compression ratios and the removal of intake throttle valves (like Diesel), and allow very low levels of urban pollutants like nitric oxide and soot (like Otto). These engines, however, are not without their challenges, such as low power density compared with other engine technologies, and a difficulty in controlling combustion timing. This dissertation first addresses the power output limits. The particular strategies for enabling high power output investigated in this dissertation focus on avoiding five critical limits that either damage an engine, drastically reduce efficiency, or drastically increase emissions: (1) ringing limits, (2) peak in-cylinder pressure limits, (3) misfire limits, (4) low intake temperature limits, and (5) excessive emissions limits. The research shows that the key factors that enable high power output, sufficient for passenger vehicles, while simultaneously avoiding the five limits defined above are the use of: (1) high intake air pressures allowing improved power output, (2) highly delayed combustion timing to avoid ringing limits, and (3) using the highest possible equivalence ratio before encountering ringing limits. These results are revealed by conducting extensive experiments spanning a wide range of operating conditions on a multi-cylinder HCCI engine. Second, this dissertation discusses strategies for effectively sensing combustion characteristics on a HCCI engine. For effective feedback control of HCCI combustion timing, a sensor is required to quantify when combustion occurs. Many laboratory engines use in-cylinder pressure sensors but these sensors are currently prohibitively expensive for wide-scale commercialization. Instead, ion sensors made from inexpensive sparkplugs

  12. Fundamental phenomena affecting low temperature combustion and HCCI engines, high load limits and strategies for extending these limits

    KAUST Repository

    Saxena, Samveg

    2013-10-01

    Low temperature combustion (LTC) engines are an emerging engine technology that offers an alternative to spark-ignited and diesel engines. One type of LTC engine, the homogeneous charge compression ignition (HCCI) engine, uses a well-mixed fuel–air charge like spark-ignited engines and relies on compression ignition like diesel engines. Similar to diesel engines, the use of high compression ratios and removal of the throttling valve in HCCI allow for high efficiency operation, thereby allowing lower CO2 emissions per unit of work delivered by the engine. The use of a highly diluted well-mixed fuel–air charge allows for low emissions of nitrogen oxides, soot and particulate matters, and the use of oxidation catalysts can allow low emissions of unburned hydrocarbons and carbon monoxide. As a result, HCCI offers the ability to achieve high efficiencies comparable with diesel while also allowing clean emissions while using relatively inexpensive aftertreatment technologies. HCCI is not, however, without its challenges. Traditionally, two important problems prohibiting market penetration of HCCI are 1) inability to achieve high load, and 2) difficulty in controlling combustion timing. Recent research has significantly mitigated these challenges, and thus HCCI has a promising future for automotive and power generation applications. This article begins by providing a comprehensive review of the physical phenomena governing HCCI operation, with particular emphasis on high load conditions. Emissions characteristics are then discussed, with suggestions on how to inexpensively enable low emissions of all regulated emissions. The operating limits that govern the high load conditions are discussed in detail, and finally a review of recent research which expands the high load limits of HCCI is discussed. Although this article focuses on the fundamental phenomena governing HCCI operation, it is also useful for understanding the fundamental phenomena in reactivity controlled

  13. The Effects of Charge Stratification on the Limit Load and Combustion Characteristics of HCCI Gasoline Engine%混合气分层对HCCI汽油机极限负荷和燃烧特性的影响

    Institute of Scientific and Technical Information of China (English)

    张建珍; 刘军

    2011-01-01

    对比研究HCCI汽油机在不同空燃比下采用混合气分层策略时的极限负荷、NOx排放量和燃油经济性,考察了在此策略下过量空气系数λ和EGR率对HCCI发动机燃烧特性的影响.结果表明,混合气分层压缩燃烧模式能有效降低HCCI燃烧的压力升高率,具有拓展负荷范围的潜力,但同时也使NOx排放增加;适当的过量空气系数能在一定程度上改善HCCI发动机的燃烧特性,采用9%的EGR率时发动机油耗率最低,具有明显节油效果.%The limit loads, N0x emission and fuel economy of HCCI gasoline engine with a mixture forming strategy of charge stratification under different air-fuel ratio are comparatively studied. With this strategy the effects of EGR rate and excess air coefficient on the combustion characteristics of HCCI engine are investigated. The results indicate that stratified charge compression ignition can reduce the rising rate of combustion pressure and has the potential for extending load range of HCCI mode, but it leads to a higher N0x emission; the appropriate excess air coefficient can improve the combustion characteristics of HCCI engine and the specific fuel consumption reaches its lowest point at a EGR rate of 9% , showing tangible results of fuel saving.

  14. Reduction of HCCI combustion noise through piston crown design

    DEFF Research Database (Denmark)

    Pedersen, Troels Dyhr; Schramm, Jesper

    2010-01-01

    Seven shapes of piston crowns have been evaluated for their ability to reduce HCCI knock and transmission of combustion noise to the engine. The performance of each piston crown was evaluated with measurements of cylinder pressure, engine vibration and acoustic sound pressure measured one meter a...

  15. Chemical Kinetic Models for HCCI and Diesel Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Pitz, W J; Westbrook, C K; Mehl, M; Sarathy, S M

    2010-11-15

    Predictive engine simulation models are needed to make rapid progress towards DOE's goals of increasing combustion engine efficiency and reducing pollutant emissions. These engine simulation models require chemical kinetic submodels to allow the prediction of the effect of fuel composition on engine performance and emissions. Chemical kinetic models for conventional and next-generation transportation fuels need to be developed so that engine simulation tools can predict fuel effects. The objectives are to: (1) Develop detailed chemical kinetic models for fuel components used in surrogate fuels for diesel and HCCI engines; (2) Develop surrogate fuel models to represent real fuels and model low temperature combustion strategies in HCCI and diesel engines that lead to low emissions and high efficiency; and (3) Characterize the role of fuel composition on low temperature combustion modes of advanced combustion engines.

  16. Digital signal processing of cylinder pressure data for combustion diagnostics of HCCI engine

    Science.gov (United States)

    Kumar Maurya, Rakesh; Pal, Dev Datt; Kumar Agarwal, Avinash

    2013-03-01

    Diagnosis of combustion is necessary for the estimation of the combustion quality, and control of combustion timing in advanced combustion concepts like HCCI. Combustion diagnostics is often performed using digital processing of pressure signals measured using piezoelectric sensor installed in the combustion chamber of the engine. Four-step pressure signal processing consisting of (i) absolute pressure correction, (ii) phasing w.r.t. crank angle, (iii) cycle averaging and (iv) smoothening is used to get cylinder pressure data from the engine experiments, which is further analyzed to get information about combustion characteristics. This study focuses on various aspect of signal processing (cycle averaging and smoothing) of in-cylinder pressure signal from a HCCI engine acquired using a piezoelectric pressure sensor. Experimental investigations are conducted on a HCCI combustion engine operating at different engine speed/load/air-fuel ratio conditions. The cylinder pressure history of 3000 consecutive engine cycles is acquired for analysis using piezoelectric pressure sensor. This study determines the optimum number of engine cycles to be acquired for reasonably good pressure signals based on standard deviation of in-cylinder pressure, rate of pressure rise and rate of heat release signals. Different signal smoothening methods (using various digital filters) are also analyzed and their results are compared. This study also presents effect of signal processing methods on pressure, pressure rise rate and rate of heat release curves at different engine operating conditions.

  17. Sensitivity of natural gas HCCI combustion to fuel and operating parameters using detailed kinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S; Dibble, R; Flowers, D; Smith, J R; Westbrook, C K

    1999-07-19

    This paper uses the HCT (Hydrodynamics, Chemistry and Transport) chemical kinetics code to analyze natural gas HCCI combustion in an engine. The HCT code has been modified to better represent the conditions existing inside an engine, including a wall heat transfer correlation. Combustion control and low power output per displacement remain as two of the biggest challenges to obtaining satisfactory performance out of an HCCI engine, and these are addressed in this paper. The paper considers the effect of natural gas composition on HCCI combustion, and then explores three control strategies for HCCI engines: DME (dimethyl ether) addition, intake heating and hot EGR addition. The results show that HCCI combustion is sensitive to natural gas composition, and an active control may be required to compensate for possible changes in composition. The three control strategies being considered have a significant effect in changing the combustion parameters for the engine, and should be able to control HCCI combustion.

  18. Quasi-Dimensional Modeling of a CNG Fueled HCCI Engine Combustion Using Detailed Chemical Kinetic

    Directory of Open Access Journals (Sweden)

    Younes Bakhshan

    2013-01-01

    Full Text Available In this study, an in-house quasi dimensional code has been developed which simulates the intake, compression, combustion, expansion and exhaust strokes of a homogeneous charge compression ignition (HCCI engine. The compressed natural gas (CNG has been used as fuel. A detailed chemical kinetic scheme constituting of 310 and 1701 elementary equations developed by Bakhshan et al. has been applied for combustion modeling and heat release calculations. The zero-dimensional k-ε turbulence model has been used for calculation of heat transfer. The output results are the performance and pollutants emission and combustion characteristics in HCCI engines. Parametric studies have been conducted to discussing the effects of various parameters on performance and pollutants emission of these engines.

  19. Review of homogeneous charge compression ignition (HCCI) combustion engines and exhaust gas recirculation (EGR) effects on HCCI

    Science.gov (United States)

    Akma Tuan Kamaruddin, Tengku Nordayana; Wahid, Mazlan Abdul; Sies, Mohsin Mohd

    2012-06-01

    This paper describes the development in ICE which leads to the new advanced combustion mode named Homogeneous Charge Compression Ignition (HCCI). It explains regarding the theory and working principle of HCCI plus the difference of the process in gasoline and diesel fuelled engines. Many of pioneer and recent research works are discussed to get the current state of art about HCCI. It gives a better indication on the potential of this method in improving the fuel efficiency and emission produced by the vehicles' engine. Apart from the advantages, the challenges and future trend of this technology are also included. HCCI is applying few types of control strategy in producing the optimum performance. This paper looks into Exhaust Gas Recirculation (EGR) as one of the control strategies.

  20. Analysis of cyclic variability in spark-assisted HCCI combustion using a double Wiebe function

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Robert M [ORNL; Glewen, William J [ORNL; Edwards, Kevin Dean [ORNL; Daw, C Stuart [ORNL

    2008-01-01

    A heuristic algorithm based on a double Wiebe function is proposed for estimating the relative importance of distinct combustion modes (propagating flame and compression ignition) occurring within individual combustion cycles as an engine is transitioned from conventional spark-ignited (SI) combustion to homogeneous charge compression ignition (HCCI). The proposed algorithm automates the analysis and categorization of pressure measurements from large numbers of individual cycles, providing new insight into the unstable combustion processes occurring during mode transition. Similar techniques could potentially be utilized for on-line diagnostics and control of the balance between SI and HCCI combustion in spark-assisted HCCI.

  1. Control concepts for a gasoline HCCI combustion engine; Strategien zur Regelung von HCCI-Brennverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Karrelmeyer, Roland; Fischer, Wolfgang [Robert Bosch GmbH, Stuttgart (Germany). CR/AEH; Graf, Gerald [Robert Bosch GmbH, Stuttgart (Germany). DGS-EC/ESG; Scherrer, Daniel [Robert Bosch GmbH, Stuttgart (Germany). GS/ECS1; Hathout, Jean-Pierre [Bosch Thermotechnology Sanayi ve Ticaret, A.S. Organize Sanayi Boelgesi, Manisa (Turkey)

    2009-07-01

    In this paper, we discuss an in-cylinder-pressure based controls concept for a HCCI-engine with internal exhaust-gas trapping. Combustion is controlled via the fuel- and air-path. The controls concept is based upon a combination of a feed-forward and a feed-back path. The work has been carried out on gasoline engines with direct-injection and different types of flexible valve trains. In a first step it will be considered a fully flexible type of valve train. On based of cost optimal aspects flexibility will be decreased which resulted in a partly flexible valve train with cam phasers an e. g. two step lift control. A control strategy based on this type of valve train also will be considered. (orig.)

  2. Investigation and Optimization of Biodiesel Chemistry for HCCI Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Bunting, Bruce G. [ORNL; Bunce, Michael [ORNL; Joyce, Blake [ORNL; Crawford, Robert W. [Rincon Ranch Consulting

    2014-06-23

    Over the past 5 years, ORNL has run 95 diesel range fuels in homogene-ous charge compression ignition (HCCI), including 40 bio-diesels and associated diesel fuels in their blending. The bio-diesel blends varied in oxygen content, iodine number, cetane, boiling point distribution, chemical composition, and some contained nitrogen. All fuels were run in an HCCI engine at 1800 rpm, in the power range of 2.5 to 4.5 bar IMEP, using intake air heating for combustion phasing control, and at a compression ratio of 10.6. The engine response to fuel variables has been analyzed statistically. Generally, the engine responded well to fuels with lower nitrogen and oxygen, lower cetane, and lower aromatics. Because of the wide range of fuels combined in the model, it provides only a broad overview of the engine response. It is recommended that data be truncated and re-modeled to obtain finer resolution of engine response to particular fuel variables.

  3. Influences of Catalytic Combustion on the Ignition Timing and Emissions of HCCI Engines

    Institute of Scientific and Technical Information of China (English)

    ZENG Wen; XIE Mao-zhao

    2008-01-01

    The combustion processes of homogeneous charge compression ignition (HCCI) engines whose piston surfaces have been coated with catalyst (rhodium or platinum) were numerically investigated. A single-zone model and a multi-zone model were developed. The effects of catalytic combustion on the ignition timing of the HCCI engine were analyzed through the single-zone model. The results showed that the ignition timing of the HCCI engine was advanced by the catalysis. The effects of catalytic combustion on HC, CO and NOx emissions of the HCCI engine were analyzed through the multi-zone model. The results showed that the emissions of HC and CO (using platinum (Pt) as catalyst) were decreased, while the emissions of NOx were elevated by catalytic combustion. Compared with catalyst Pt, the HC emissions were lower with catalyst rhodium(Rh) on the piston surface, but the emissions of NOx and CO were higher.

  4. Autoignition and Combustion of Natural Gas in a 4 Stroke HCCI Engine

    Science.gov (United States)

    Jun, Daesu; Ishii, Kazuaki; Iida, Norimasa

    Homogeneous charge compression ignition (HCCI) is regarded as the next generation combustion regime in terms of high thermal efficiency and low emissions. It is difficult to control autoignition timing and combustion duration because they are controlled primarily by the chemical kinetics of fuel-air mixture. In this study, it was investigated the characteristics of autoignition and combustion of natural gas in a 4 stroke HCCI engine. And also, to clarify the influence of n-butane on autoignition and combustion of natural gas, it was changed the blend ratio of n-butane from 0mol% to 10mol% in methane/n-butane/air mixtures. Autoignition strongly depends on in-cylinder gas temperature. Autoignition of natural gas occurs when in-cylinder gas temperature reaches in a range of 1000±100K under this experimental condition. To realize high thermal efficiency and low CO emissions, it is necessary to prepare operation conditions that maximum cycle temperature is over 1500K. Autoignition temperature is 25K lower by increasing n-butane blend ratio of 10%. As the blend ratio of n-butane increases, the maximum cycle temperature increases, and THC, CO emissions reduce.

  5. Investigation of combustion, performance and emission characteristics of 2-stroke and 4-stroke spark ignition and CAI/HCCI operations in a DI gasoline

    OpenAIRE

    Y. Zhang; Zhao, H.

    2014-01-01

    In order to develop more efficient and cleaner gasoline engines, a number of new engine operating strategies have been proposed and researched on different engines, including the spark ignition (SI) and controlled autoignition (CAI) or HCCI in both 2-stroke and 4-stroke cycles in a poppet valve engine. In this work, a single cylinder direct injection gasoline engine equipped with an electro-hydraulic valve-train system has been commissioned and used to achieve seven different operating modes,...

  6. 基于循环的瞬态空燃比对乙醇HCCI发动机燃烧特性的影响%Effects of Cyclic Real Time Air/Fuel Ratios on Combustion Characteristics in an Ethanol DI-HCCI Engine

    Institute of Scientific and Technical Information of China (English)

    邓俊; 刘寅童; 吴志军; 胡宗杰; 李理光

    2013-01-01

    均质充量压燃(HCCI)技术对于燃烧循环间变动较敏感,且循环间的瞬态空燃比对燃烧特性有重要影响.在缸内直喷HCCI发动机试验台架上,利用瞬态CO/CO2排放测试仪,对乙醇HCCI燃烧循环间瞬态空燃比进行检测,并将瞬态空燃比与燃烧特性参数进行对比分析.结果表明,连续循环的瞬态空燃比变化较明显,在其平均值附近波动且服从正态分布规律.由于乙醇汽化潜热高,喷油量增加引起的瞬态温度下降会导致燃烧相位后移,燃烧持续期延长.%HCCI combustion is much sensitive to cyclic variations. The transient air/fuel ratio has an important effect on combustion characteristics. Fast CO2/C(X HC and NOx measurement systems were employed to detect the transient emissions and real time air/fuel ratio of an ethanol fueled DI-HCCI. Effect of real time air/fuel ratio on combustion characteristics was analyzed. Results show that real time air/fuel ratio of continuous combustion cycles fluctuates to the averaged value and follows the normal distribution. For high latent heat of ethanol, the decreasing of temperature by increasing fuel injection quantity postpones combustion phase and increases combustion duration.

  7. Reaction Mechanisms and HCCI Combustion Processes of Mixtures of n-Heptane and the Butanols

    Directory of Open Access Journals (Sweden)

    Hu eWang

    2015-03-01

    Full Text Available A reduced primary reference fuel (PRF-Alcohol-Di-tert-butyl Peroxide (DTBP mechanism with 108 species and 435 reactions, including sub-mechanisms of PRF, methanol, ethanol, DTBP and the four butanol isomers, is proposed for homogeneous charge compression ignition (HCCI engine combustion simulations of butanol isomers/n-heptane mixtures. HCCI experiments fuelled with butanol isomer/n-heptane mixtures on two different engines are conducted for the validation of proposed mechanism. The mechanism has been validated against shock tube ignition delays, laminar flame speeds, species profiles in premixed flames and engine HCCI combustion data, and good agreements with experimental results are demonstrated under various validation conditions. It is found that although the reactivity of neat tert-butanol is the lowest, mixtures of tert-butanol/n-heptane exhibit the highest reactivity among the butanol isomer/n-heptane mixtures if the n-heptane blending ratio exceeds 20% (mole. Kinetic analysis shows that the highest C-H bond energy in the tert-butanol molecule is partially responsible for this phenomenon. It is also found that the reaction tC4H9OH+CH3O2 =tC4H9O+CH3O2H plays important role and eventually produces the OH radical to promote the ignition and combustion. The proposed mechanism is able to capture HCCI combustion processes of the butanol/n-heptane mixtures under different operating conditions. In addition, the trend that tert-butanol /n-heptane has the highest reactivity is also captured in HCCI combustion simulations. The results indicate that the current mechanism can be used for HCCI engine predictions of PRF and alcohol fuels.

  8. Model and experiments of diesel fuel HCCI combustion with external mixture formation

    Energy Technology Data Exchange (ETDEWEB)

    Canova, M.; Vosz, A.; Dumbauld, D.; Garcin, R.; Midlam-Mohler, S.; Guezennec, Y.; Rizzoni, G. [Ohio State Univ. (United States)

    2005-07-01

    Homogeneous Charge Compression Ignition represents a promising concept for achieving high efficiencies and low emissions at part-load operations. In particular, HCCI combustion can be successfully applied to conventional Direct Injection Diesel engines with very low extra costs and no modification to the DI system by performing the mixture formation in the intake manifold with a novel fuel atomizer. The present paper describes the experimental and modeling activity oriented to the control of HCCI combustion on a conventional CIDI 4-cylinder engine fitted with this external fueling device. Paralleling preliminary results obtained last year on single-cylinder engine in collaboration with FKFS at the University of Stuttgart, Diesel-fuel HCCI combustion was achieved and characterized over a range of engine speeds, loads, EGR dilution and boost pressure. Stable HCCI combustion with negligible NO{sub x} formation (10 ppm) was achieved with no modification of a high compression ratio engine (c{sub r}=18). The in-cylinder pressure traces were analyzed by performing a detailed heat release analysis while accounting for the wall heat transfer, which is substantially higher during the combustion phase than in a conventional CIDI engine. This analysis led to the joint identification of 2 sub-models: a heat transfer model, and a heat release model. It was found that under the wide range of conditions experimentally measured, the heat release can be approximated by the superposition of 3 Wiebe functions. The sub-models developed were then implemented in a combustion model based on a first-law thermodynamic analysis of in-cylinder processes, in order to identify the influence of the main control parameters on HCCI auto-ignition and to control the combustion process in a HCCI Diesel engine with external mixture formation. The model predictions were then compared to the results of a parallel experimental activity made on a 4-cylinder CIDI Diesel engine equipped with the fuel

  9. RESEARCH ON COMBUSTION CHARACTERISTICS OF HCCI BASED ON GASOLINE DIRECT INJECTION%基于缸内直喷的汽油HCCI燃烧特性的研究

    Institute of Scientific and Technical Information of China (English)

    王建昕; 帅石金; 王志

    2008-01-01

    实现汽油机的均质混合气压燃(HCCI)的难点是精确地控制着火时刻、燃烧速率以及扩展高负荷运行范围.在缸内直喷汽油机(GDI)上试验研究了分层混合气和辅助火花点火对HCCI燃烧特性的影响,考察了对不同运行工况时的适应性.开展了负阀重叠与缸内多段喷油相结合控制HCCI着火稳定性的研究,考察了不同喷油控制策略对HCCI燃烧的影响,确定了HCCI运行工况范围.

  10. Controlling the heat release in HCCI combustion of DME with methanol and EGR

    DEFF Research Database (Denmark)

    Pedersen, Troels Dyhr; Schramm, Jesper; Yanai, Tadanori

    2010-01-01

    The effects of methanol and EGR on HCCI combustion of dimethyl ether have been tested separately in a diesel engine. The engine was equipped with a common rail injection system which allowed for random injection of DME. The engine could therefore be operated either as a normal DI CI engine or, by...

  11. Controlling the heat release in HCCI combustion of DME with methanol and EGR

    DEFF Research Database (Denmark)

    Pedersen, Troels Dyhr; Schramm, Jesper; Yanai, Tadanori

    2010-01-01

    The effects of methanol and EGR on HCCI combustion of dimethyl ether have been tested separately in a diesel engine. The engine was equipped with a common rail injection system which allowed for random injection of DME. The engine could therefore be operated either as a normal DI CI engine or, by...

  12. Combustion Mode Transition Between HCCI and SI in Load Transition%变工况条件下HCCI/SI燃烧模式转换的实现

    Institute of Scientific and Technical Information of China (English)

    陈韬; 谢辉; 李乐; 虞卫飞; 张松; 赵华

    2012-01-01

    In order to satisfy the request of vehicle engine, SI combustion still needs to be used beyond HCCI operating range. At present, all the methods of HCCI/SI combustion mode transition are realized at the same load, which increases controlling difficulties and brings load fluctuation. To solve the problem of mode transition, a gradual transition from HCCI to SI combustion in load transition was performed by using the variable valve actuation system and external exhaust gas recirculation, and the strategy that the load of engine is controlled by exhaust gas fraction in HCCI combustion was introduced into the SI combustion. The control strategy for all-load is simplified, due to the fact that the complicated control of mode switching has been eliminated.%为了满足车用发动机的要求,在HCCI燃烧的运行范围之外,仍需要使用火花点火(SI)燃烧模式.目前HCCI/SI模式转换的方法和策略都是在相同工况下完成的,这增加了控制上的难度并会带来负荷波动.针对此问题,采用全可变气门机构结合外部废气再循环的方法,在变工况条件下,完成HCCI和SI燃烧模式的转化.并将HCCI燃烧模式中废气率调整负荷的方法延伸进SI燃烧控制中.由于在控制策略层面,采用模式过渡的方法,消除了HCCI/SI模式转换的概念,因而简化了控制策略.

  13. Study the ethanol SI/HCCI combustion mode transition by using the fast thermal management system

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper the ethanol homogeneous charge compression ignition (HCCI) is achieved in a modified single cylinder engine by means of a self-developed fast thermal management system (FTMS), and the ethanol SI/HCCI operation regions are defined. It can be concluded that the thermal efficiency is higher and the NOx emission is lower in the HCCI operation region. In addition, the maximum NOx emission drops by 98%. The ethanol SI/HCCI combustion mode transition is conducted in different conditions near the SI/HCCI operation boundaries. It is likely to realize the transition by the utilization of FTMS. However, it is impossible to complete the transition within one operating cycle under current operation conditions. There are fluctuations in engine speed and brake mean effective pressure during the transition process. In order to reduce the fluctuations during the transition, the initial work concerning the effects of the spark ignition on the transition smoothness is carried out and the investigation indicates that the engine speed and brake mean effective pressure fluctuations cannot be eradicated only through spark ignition. Therefore, the control strategies combined with other factors should be further optimized.

  14. Numerical study of premixed HCCI engine combustion and its sensitivity to computational mesh and model uncertainties

    Science.gov (United States)

    Kong, Song-Charng; Reitz, Rolf D.

    2003-06-01

    This study used a numerical model to investigate the combustion process in a premixed iso-octane homogeneous charge compression ignition (HCCI) engine. The engine was a supercharged Cummins C engine operated under HCCI conditions. The CHEMKIN code was implemented into an updated KIVA-3V code so that the combustion could be modelled using detailed chemistry in the context of engine CFD simulations. The model was able to accurately simulate the ignition timing and combustion phasing for various engine conditions. The unburned hydrocarbon emissions were also well predicted while the carbon monoxide emissions were under predicted. Model results showed that the majority of unburned hydrocarbon is located in the piston-ring crevice region and the carbon monoxide resides in the vicinity of the cylinder walls. A sensitivity study of the computational grid resolution indicated that the combustion predictions were relatively insensitive to the grid density. However, the piston-ring crevice region needed to be simulated with high resolution to obtain accurate emissions predictions. The model results also indicated that HCCI combustion and emissions are very sensitive to the initial mixture temperature. The computations also show that the carbon monoxide emissions prediction can be significantly improved by modifying a key oxidation reaction rate constant.

  15. Effect of water blending on bioethanol HCCI combustion with forced induction and residual gas trapping

    Energy Technology Data Exchange (ETDEWEB)

    Megaritis, A. [Mechanical Engineering, School of Engineering and Design, Brunel University, West London, Uxbridge UB8 3PH (United Kingdom); Yap, D. [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore); Wyszynski, M.L. [Mechanical and Manufacturing Engineering, School of Engineering, University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2007-12-15

    There is increased interest worldwide in renewable engine fuels as well as in new combustion technologies. Bioethanol is one of the alternative fuels that have been used successfully in spark ignition engines. A combustion technology that currently attracts a lot of interest is the homogeneous charge compression ignition (HCCI) combustion, which has shown potential for low nitrogen oxides emissions with no particulate matter formation. The authors have shown previously that applying forced induction to bioethanol HCCI with residual gas trapping results in an extended load range compared to naturally aspirated operation. However, at high boost pressures, high cylinder pressure rise rates develop. Work by other researchers has shown that direct injection of water can be used as a combustion control method. The present work explores water blending as a way that might have an effect on combustion in order to lower the maximum pressure rise rates and further improve emissions. The obtained experimental results show that in contrast to variable rate direct injection of water, fixed rate water-ethanol blending is counterproductive for the reduction of pressure rise rates at higher loads. In addition, increasing the water content in ethanol results in reduction of the effective load range and increased emissions. (author)

  16. Numerical Investigation Into Effect of Fuel Injection Timing on CAI/HCCI Combustion in a Four-Stroke GDI Engine

    Science.gov (United States)

    Cao, Li; Zhao, Hua; Jiang, Xi; Kalian, Navin

    2006-02-01

    The Controlled Auto-Ignition (CAI) combustion, also known as Homogeneous Charge Compression Ignition (HCCI), was achieved by trapping residuals with early exhaust valve closure in conjunction with direct injection. Multi-cycle 3D engine simulations have been carried out for parametric study on four different injection timings in order to better understand the effects of injection timings on in-cylinder mixing and CAI combustion. The full engine cycle simulation including complete gas exchange and combustion processes was carried out over several cycles in order to obtain the stable cycle for analysis. The combustion models used in the present study are the Shell auto-ignition model and the characteristic-time combustion model, which were modified to take the high level of EGR into consideration. A liquid sheet breakup spray model was used for the droplet breakup processes. The analyses show that the injection timing plays an important role in affecting the in-cylinder air/fuel mixing and mixture temperature, which in turn affects the CAI combustion and engine performance.

  17. Operating strategies on HCCI combustion; Betriebsstrategien fuer die Benzinselbstzuendung

    Energy Technology Data Exchange (ETDEWEB)

    Babic, Goran; Bargende, Michael [Stuttgart Univ. (DE). Inst. fuer Verbrennungsmotoren und Kraftfahrzeuge (IVK)

    2010-09-15

    The gasoline self-ignition represents an alternative part load combustion strategy, which radically reduces the nitrogen-oxide emissions in combination with improved process efficiency. At the request of the Research Association for Combustion Engines (FVV) the Institute for Internal Combustion Engines and Automotive Engineering (IVK) of the University of Stuttgart investigated different operating strategies on gasoline self-ignition and developed methods for mode switches under close-to-production conditions. (orig.)

  18. Combustion optimization and HCCI modeling for ultra low emission

    Energy Technology Data Exchange (ETDEWEB)

    Koten, Hasan; Yilmaz, Mustafa; Zafer Gul, M. [Marmara University Mechanical Engineering Department (Turkey)], E-mail: hasan.koten@marmara.edu.tr

    2011-07-01

    With the coming shortage of fossil fuels and the rising concerns over the environment it is important to develop new technologies both to reduce energy consumption and pollution at the same time. In the transportation sector, new combustion processes are under development to provide clean diesel combustion with no particulate or NOx emissions. However, these processes have issues such as limited power output, high levels of unburned hydrocarbons, and carbon monoxide emissions. The aim of this paper is to present a methodology for optimizing combustion performance. The methodology consists of the use of a multi-objective genetic algorithm optimization tool; homogeneous charge compression ignition engine cases were studied with the ECFM-3Z combustion model. Results showed that injected fuel mass led to a decrease in power output, a finding which is in keeping with previous research. This paper presented on optimization tool which can be useful in improving the combustion process.

  19. 催化燃烧对均质压燃发动机燃烧特性影响的数值模拟%Numerical Simulation of the Influences of Catalytic Combustion on HCCI Engine Combustion Characteristics

    Institute of Scientific and Technical Information of China (English)

    曾文; 解茂昭; 贾明

    2006-01-01

    通过运用DETCHEM软件包,对甲烷在催化剂Rh表面的详细反应机理进行了分析,结果表明数值模拟结果与实验数据相当吻合;通过耦合DETCHEM软件包及CHEMKIN软件包中的SENKIN模块,对活塞顶涂有催化剂铑的均质压燃(HCCI)发动机的燃烧过程进行了数值计算,建立了单区和多区模型.利用单区模型分析了催化燃烧对HCCI发动机着火时刻的影响,同时讨论了催化燃烧对燃烧过程中主要化学组分浓度变化的影响,结果表明催化燃烧会使HCCI发动机着火时刻提前;利用多区模型分析了催化燃烧对HCCI发动机的未燃碳氢化合物(UHC)、氮氧化合物(NOx)排放的影响,结果表明催化燃烧能降低UHC的排放,但会提高NOx的排放.

  20. Interactions Between Surface Reactions and Gas-phase Reactions in Catalytic Combustion and Their Influence on Ignition of HCCI Engine

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The catalytic combustion of methane in a microchannel whose surface was coated with platinum(Pt)catalyst was studied by numerical-simulation. The effects of gas-phase reactions on the whole catalytic combustion process were analyzed at a high inlet pressure. A sensitivity analysis of the detailed mechanisms of the surface reaction of methane on Pt revealed that the most sensitive reactions affecting the heterogeneous ignition are oxygen adsorption/desorption and methane adsorption, and the most sensitive reactions affecting the homogeneous ignition are OH and H2O adsorption/desorption. The combustion process of the homogeneous charge compression ignition(HCCI) engine whose piston face was coated with Pt catalyst was simulated. The effects of catalysis and the most sensitive reactions on the ignition timing and the concentration of the main intermediate species during the HCCI engine combustion are discussed. The results show that the ignition timing of the HCCI engine can be increased by catalysis, and the most sensitive reactions affecting the ignition timing of the HCCI engine are OH and H2O adsorption/desorption.

  1. A numerical study of HCCI combustion of PRF mixtures compared with PCCI experiments

    Energy Technology Data Exchange (ETDEWEB)

    Van Wijngaarden, B.

    2008-09-15

    For automotive applications engines that produce less soot and NOx are desired. For that reason the Homogeneous Charge Compression Ignition (HCCI) principle is investigated all over the world, including the technical universities of Berlin (TUB) and Eindhoven. HCCI combines a homogeneous charge, as in an Otto engine with the autoignition principle of a Diesel engine. Auto-ignition and almost instantaneous combustion of a homogeneous charge leads to almost zero soot emissions, lower temperatures and thereby much lower NOx emissions. Auto-ignition timing however, depends on the fuel and its chemistry, which is very sensitive to the applied conditions, being pressure, temperature, equivalence ratio ({phi}), dilution with EGR and engine speed. To study this systematically a 0D model with PRF fuels is used (Primary Reference Fuels are n-heptane, iso-octane and mixtures). A 0D model is chosen because it excludes complex fluid dynamics and thereby allows the use of detailed combustion mechanisms, describing the (PRF) chemistry. Furthermore the model has a multi zone possibility to evaluate in-homogeneities of the charge. PRF fuels are used because n-heptane (CN=55) auto-ignites like a diesel and iso-octane (ON=100) approaches gasoline. For the PRF chemistry three combustion mechanisms were selected, of which two were validated showing a great difference in predicted ignition delay and sensitivity to changes. Furthermore the model was validated with a PCCI (Premixed Charge Compression Ignition) experiment. Extensive comparisons with PCCI experiments from the TUB showed that when the moment of injection was used to launch the chemistry in the model, only the Soyhan mechanism predicted the ignition close to the experimental ignition moment. Furthermore a 7 zone model was able to approach the experimental CO and NOX emissions. Finally none of the mechanisms was able to predict a pressure profile similar to the experiments. More zones and or a better mechanism could improve

  2. Performance of HCCI Diesel Engine under the Influence of Various Working and Geometrical Parameters

    OpenAIRE

    Karthikeya Sharma, T.; G. Amba Prasada Rao; K.Madhu Murthy

    2012-01-01

    Homogenous-charge-compression-ignition (HCCI) engines have the benefit of high efficiency with low emissions of NO and particulates. These benefits are due to the autoignition process of the dilute mixture of fuel and air during compression. Homogenous Compression ignition (HCCI) is a combustion concept, which is a hybrid between Otto engine and Diesel engine. The other emissions like HC and CO are high but can be after treated by a catalyst. This paper reviews the Characteristics of HCCI com...

  3. Gasoline-like Fuel Effects on High-load, Boosted HCCI Combustion Employing Negative Valve Overlap Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Kalaskar, Vickey B [ORNL; Szybist, James P [ORNL; Splitter, Derek A [ORNL

    2014-01-01

    In recent years a number of studies have demonstrated that boosted operation combined with external EGR is a path forward for expanding the high load limit of homogeneous charge compression ignition (HCCI) operation with the negative valve overlap (NVO) valve strategy. However, the effects of fuel composition with this strategy have not been fully explored. In this study boosted HCCI combustion is investigated in a single-cylinder research engine equipped with direct injection (DI) fueling, cooled external exhaust gas recirculation (EGR), laboratory pressurized intake air, and a fully-variable hydraulic valve actuation (HVA) valve train. Three fuels with significant compositional differences are investigated: regular grade gasoline (RON = 90.2), 30% ethanol-gasoline blend (E30, RON = 100.3), and 24% iso-butanol-gasoline blend (IB24, RON = 96.6). Results include engine loads from 350 to 800 kPa IMEPg for all fuels at three engine speeds 1600, 2000, and 2500 rpm. All operating conditions achieved thermal efficiency (gross indicated efficiency) between 38 and 47%, low NOX emissions ( 0.1 g/kWh), and high combustion efficiency ( 96.5%). Detailed sweeps of intake manifold pressure (atmospheric to 250 kPaa), EGR (0 25% EGR), and injection timing are conducted to identify fuel-specific effects. The major finding of this study is that while significant fuel compositional differences exist, in boosted HCCI operation only minor changes in operational conditions are required to achieve comparable operation for all fuels. In boosted HCCI operation all fuels were able to achieve matched load-speed operation, whereas in conventional SI operation the fuel-specific knock differences resulted in significant differences in the operable load-speed space. Although all fuels were operable in boosted HCCI, the respective air handling requirements are also discussed, including an analysis of the demanded turbocharger efficiency.

  4. A new predictive multi-zone model for HCCI engine combustion

    Energy Technology Data Exchange (ETDEWEB)

    Bissoli, M.; Frassoldati, A.; Cuoci, A.; Ranzi, E.; Mehl, M.; Faravelli, T.

    2016-09-01

    This work introduces a new predictive multi-zone model for the description of combustion in Homogeneous Charge Compression Ignition (HCCI) engines. The model exploits the existing OpenSMOKE++ computational suite to handle detailed kinetic mechanisms, providing reliable predictions of the in-cylinder auto-ignition processes. All the elements with a significant impact on the combustion performances and emissions, like turbulence, heat and mass exchanges, crevices, residual burned gases, thermal and feed stratification are taken into account. Compared to other computational approaches, this model improves the description of mixture stratification phenomena by coupling a wall heat transfer model derived from CFD application with a proper turbulence model. Furthermore, the calibration of this multi-zone model requires only three parameters, which can be derived from a non-reactive CFD simulation: these adaptive variables depend only on the engine geometry and remain fixed across a wide range of operating conditions, allowing the prediction of auto-ignition, pressure traces and pollutants. This computational framework enables the use of detail kinetic mechanisms, as well as Rate of Production Analysis (RoPA) and Sensitivity Analysis (SA) to investigate the complex chemistry involved in the auto-ignition and the pollutants formation processes. In the final sections of the paper, these capabilities are demonstrated through the comparison with experimental data.

  5. A Study on the Effects of Compression Ratio, Engine Speed and Equivalence Ratio on HCCI Combustion of DME

    DEFF Research Database (Denmark)

    Pedersen, Troels Dyhr; Schramm, Jesper

    2007-01-01

    An experimental study has been carried out on the homogeneous charge compression ignition (HCCI) combustion of Dimethyl Ether (DME). The study was performed as a parameter variation of engine speed and compression ratio on excess air ratios of approximately 2.5, 3 and 4. The compression ratio...... was adjusted in steps to find suitable regions of operation, and the effect of engine speed was studied at 1000, 2000 and 3000 RPM. It was found that leaner excess air ratios require higher compression ratios to achieve satisfactory combustion. Engine speed also affects operation significantly....

  6. A Study on the Effects of Compression Ratio, Engine Speed and Equivalence Ratio on HCCI Combustion of DME

    DEFF Research Database (Denmark)

    Pedersen, Troels Dyhr; Schramm, Jesper

    2007-01-01

    An experimental study has been carried out on the homogeneous charge compression ignition (HCCI) combustion of Dimethyl Ether (DME). The study was performed as a parameter variation of engine speed and compression ratio on excess air ratios of approximately 2.5, 3 and 4. The compression ratio...... was adjusted in steps to find suitable regions of operation, and the effect of engine speed was studied at 1000, 2000 and 3000 RPM. It was found that leaner excess air ratios require higher compression ratios to achieve satisfactory combustion. Engine speed also affects operation significantly....

  7. Performance of HCCI Diesel Engine under the Influence of Various Working and Geometrical Parameters

    Directory of Open Access Journals (Sweden)

    T. Karthikeya Sharma

    2012-06-01

    Full Text Available Homogenous-charge-compression-ignition (HCCI engines have the benefit of high efficiency with low emissions of NO and particulates. These benefits are due to the autoignition process of the dilute mixture of fuel and air during compression. Homogenous Compression ignition (HCCI is a combustion concept, which is a hybrid between Otto engine and Diesel engine. The other emissions like HC and CO are high but can be after treated by a catalyst. This paper reviews the Characteristics of HCCI combustion in direct injection diesel engines under various governing factors in HCCI operations such as injection timing, injection pressure, piston bowl geometry, compression ratio, intake charge temperature, exhaust gas recirculation (EGR and supercharging or turbo charging are discussed in this review. The effects of design and operating parameters on HCCI diesel combustion, emissions particularly NOx and soot are reviewed.

  8. Studies of the Combustion Process with Simultaneous Formaldehyde and OH PLIF in a Direct-Injected HCCI Engine

    Science.gov (United States)

    Richter, Mattias; Collin, Robert; Nygren, Jenny; Aldén, Marcus; Hildingsson, Leif; Johansson, Bengt

    This paper presents simultaneous laser based measurements of formaldehyde and OH-radical distributions in a 0.5 liter optical HCCI engine with direct injection. Formaldehyde is formed as an intermediate species when combusting hydrocarbons. The formation occurs through low temperature reactions in an early phase of the combustion process. Later in the process formaldehyde is being consumed. Formaldehyde is, therefore, used as indicator of the first stage of combustion and a marker of zones with low-temperature reactions. The OH radical is formed as an intermediate during the high temperature reactions, and is used as a marker of zones where the combustion is ongoing. The purpose of the investigation was to study how the combustion process is affected by the change in homogeneity that arises from early and late injection, respectively. The measurement technique used was planar laser-induced fluorescence where formaldehyde was excited at 355nm and OH at 283nm.

  9. Application of micro-genetic algorithm for calibration of kinetic parameters in HCCI engine combustion model

    Institute of Scientific and Technical Information of China (English)

    Haozhong HUANG; Wanhua SU

    2008-01-01

    The micro-genetic algorithm (μGA) as a highly effective optimization method, is applied to calibrate to a newly developed reduced chemical kinetic model (40 species and 62 reactions) for the homogeneous charge compression ignition (HCCI) combustion of n-heptane to improve its autoignition predictions for different engine operating conditions. The seven kinetic parameters of the calibrated model are determined using a combination of the Micro-Genetic Algorithm and the SENKIN program of CHEMKIN chemical kinetics software package. Simulation results show that the autoignition predictions of the calibrated model agree better with those of the detailed chemical kinetic model (544 species and 2 446 reactions) than the original model over the range of equivalence ratios from 0.1-1.3 and temperature from 300-3 000 K. The results of this study have demonstrated that the μGA is an effective tool to facilitate the calibration of a large number of kinetic parameters in a reduced kinetic model.

  10. 基于振动信号及瞬时转速信号的HCCI燃烧模式辨识%HCCI Combustion Mode Detection Based on Knock Sensor Signal and Instant Speed

    Institute of Scientific and Technical Information of China (English)

    张宏超; 谢辉; 陈韬; 赵华

    2012-01-01

    HCCI engine adopts combined-mode combustion of pure SI combustion mode, SI-HCCI mode and pure HCCI mode. In such a HCCI combustion control, combustion mode identification becomes very important. Based on a great number of experiments conducted on HCCI engine bench equipped with a fully variable valve actuating system, analysis and comparison are made between knock signal, instant speed and combustion mode. Characteristic parameters are extracted from knock sensor signal and instant speed. Based on the discriminant function analysis, a combustion mode identification model is built with the characteristic parameters, which is simple in computation and easy to be implemented on microcontroller. It is shown that the model is capable of discriminating combustion modes, with the successful detecting rate of around 75%.%HCCI汽油发动机一般采用组合燃烧控制策略,根据发动机工况不同,HCCI汽油机分别采用SI燃烧模式、SI-HCCI燃烧模式和HCCI燃烧模式.在这种控制方式下,燃烧模式的辨识具有非常重要的作用与意义.笔者在装有全可变气门系统的汽油HCCI发动机上,测取HCCI发动机各工况下爆震传感器信号和瞬时转速信号,用时频分析方法从爆震传感器信号和瞬时转速信号中提取了特征量,分析了它们和HCCI汽油机燃烧模式之间的关系.通过辨识函数分析,基于爆震传感器信号特征量和瞬时转速信号特征量,建立了的HCCI燃烧模式辨识模型.分析表明,HCCI燃烧模式辨识模型能够较好地辨识出HCCI的燃烧模式,总体辨识成功率在75%左右.

  11. 混合气质量对乙醇发动机均质压燃燃烧特性的影响%Influence of mixture quality on HCCI combustion characteristics of ethanol engine

    Institute of Scientific and Technical Information of China (English)

    杨立平; 郭英男; 李君; 刘金山; 王立媛

    2008-01-01

    在一台经改造而成的单缸均质压燃(HCCI)发动机上,以乙醇为燃料研究了不同循环供油量和废气再循环(EGR)率对HCCI燃烧的动力性、经济性和排放性的影响.结果表明:乙醇燃料HCCI燃烧有较高的指示热效率,最高可以接近60%;最高平均指示压力Pmi为0.6MPa;过量空气系数φa和EGR率的合理组合可以有效控制HCCI燃烧的着火正时和NOx排放,但是EGR的加入会导致HC和CO排放增加.

  12. Effects of compression ratio on the combustion characteristics of a homogeneous charge compression ignition engine

    Institute of Scientific and Technical Information of China (English)

    SONG Ruizhi; HU Tiegang; ZHOU Longbao; LIU Shenghua; LI Wei

    2007-01-01

    The effects of homogeneous charge compression ignition (HCCI) engine compression ratio on its combustion characteristics were studied experimentally on a modified TY1100 single cylinder engine fueled with dimethyl ether.The results show that dimethyl ether (DME) HCCI engine can work stably and can realize zero nitrogen oxides (NOx)emission and smokeless combustion under the compression ratio of both 10.7 and 14.The combustion process has obvious two stage combustion characteristics at ε = 10.7(εrefers to compression ratio),and the combustion beginning point is decided by the compression temperature,which varies very little with the engine load;the combustion beginning point is closely related to the engine load (concentration of mixture) with the increase in the compression temperature,and it moves forward versus crank angle with the increase in the engine load at ε = 14;the combustion durations are shortened with the increase in the engine load under both compression ratios.

  13. Effect of EGR on combustion and emission of methanol HCCI engine%EGR对甲醇HCCI发动机燃烧与排放的影响

    Institute of Scientific and Technical Information of China (English)

    赵伟; 张春化; 佟娟娟; 吴晗

    2012-01-01

    针对均质压燃燃烧难以控制的问题,在一台发动机上,改装进排气系统,并加装均质混合气供油系统和进气加热系统,研究了外部EGR(废气再循环)对甲醇HCCI(均质充量压缩着火)燃烧与排放特性的影响。结果表明:外部EGR对甲醇HCCI燃烧过程和排放都有显著的影响,随EGR率的增加,CA10、CA50逐渐推迟,燃烧持续期逐渐延长,但影响的程度因混合气浓度的不同而变化;HC和CO排放逐渐增加,且增加的幅度逐渐变大;NOx排放仅在混合气较浓时存在(过量空气系数小于1.5时),且随着EGR率的增加迅速下降。%In order to deal with the problem that the combustion of homogeneous charge compression ignition (HCCI) is difficult to control, the impacts of external exhaust gas recirculation (EGR) on methanol HCCI combustion and emission characteristics were investigated on a modi- fied engine by modifying intake and exhaust system, adding HCCI fuel supply system and intake- heating system. The results show that the EGR has a remarkable influence on the combustion and emission of methanol HCCI. As the EGR ratio increases, CA10 and CAS0 gradually delay and the combustion duration prolongs, the change level varies with the differences of mixture concentration, the emissions of unburned hydrocarbon and monoxide carbon quickly increase. Ni- trogen oxide can only be detected at the condition of relative richer mixture (air-fuel equivalence ratio less than 1.5), and its quantity decreases quickly with the EGR ratio going up. 1 tab, 8 figs, 9 refs.

  14. Modeling and Simulation of a Free-Piston Engine with Electrical Generator Using HCCI Combustion

    Science.gov (United States)

    Alrbai, Mohammad

    governing equations represent a single zone perfectly stirred reactor (PSR) which contain a perfect mixing ideal gas mixture. The chemical kinetics approach is applied using Cantera/ MATLABRTM toolbox, which presents the combustion process. In this research, a homogenous charge compression ignition (HCCI) at different operational conditions is used. HCCI engines have high efficiencies and low emissions and can work within a wide range of fuels. The results have been presented in a multi-cycle simulation and a parametric study forms. In the case of the multi-cycle simulation, a 100 cycles of the engine operation have been simulated. The overall work that is delivered to the electrical generator presents 47% of the total fuel energy. The model indicates an average frequency of 125 Hz along the operational cycles. In order to eliminate the cyclic variations and ensure a continuous operation, a proportional derivative (PD) controller has been employed. The controller adjusts the generator load in order to minimize the difference between the bottom dead center (BDC) locations along the operation cycles. The PD controller shows weakness in achieving the full steady state operation, for this purpose; a proportional integral (PI) controller has been implemented. The PI controller seeks to achieve a specific compression ratio. The results show that; the PI controller indicates unique behavior after 15 cycles of operation where the model ended to fluctuate between two compression ratios only. The complex relation between the thermodynamics and the dynamics of the engine is the greatest challenge in examining the effectiveness of the PI controller. In the parametric investigations, EGR examinations show that NOx emission is reduced to less than the half, as 30 % of EGR is used; this occurs due to the EGR thermal and dilution effects, which cause significant drop in the peak bulk temperature and CO emissions as well. Under the applied conditions, EGR has the ability to raise the work

  15. Investigations of the causes of hydrocarbon emissions in spark ignition engines with homogeneous charge compression ignition (HCCI). A report of the Institute for Internal Combustion Engines and Automotive Engineering, TU Vienna (IVK); Untersuchung der Ursachen fuer Kohlenwasserstoff-Emissionen beim Ottomotor mit homogener Selbstzuendung (HCCI). Bericht des Instituts fuer Verbrennungskraftmaschinen und Kraftfahrzeugbau derTechnischen Universitaet Wien (IVK)

    Energy Technology Data Exchange (ETDEWEB)

    Geringer, B. (ed.) [Technische Univ., Vienna (Austria); Loch, A.

    2007-07-01

    The main aim of research and development in the field of internal combustion engine is to create an engine with low fuel consumption and hence low carbon dioxide emissions to meet future emissions regulations as well as providing a good driving experience. Homogeneous charge compression ignition (HCCI) is an alternative combustion process being currently developed that promises a good fuel consumption rate and low nitrogen oxide emissions for the gasoline engine. The only legally restricted exhaust gas emissions for this combustion process are carbon monoxide (CO) and hydrocarbons (HC). The aim of this research was a better understanding of the causes and sources of hydrocarbon emissions with HCCI using gasoline so as to further reduce hydrocarbon emissions. A description of the HCCI combustion process is followed by a list of the known sources of hydrocarbon emission in conventional gasoline engines and current knowledge of the causes of hydrocarbon emission with HCCI. It is assumed that many of the known causes of hydrocarbon emissions in the conventional gasoline combustion process are the same for HCCI. For this reason, this study focused on combustion and carburation, which is where the combustion processes differ the most. (orig.)

  16. Flex Fuel Optimized SI and HCCI Engine

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guoming; Schock, Harold; Yang, Xiaojian; Huisjen, Andrew; Stuecken, Tom; Moran, Kevin; Zhen, Ron; Zhang, Shupeng

    2013-09-30

    The central objective of the proposed work is to demonstrate an HCCI (homogeneous charge compression ignition) capable SI (spark ignited) engine that is capable of fast and smooth mode transition between SI and HCCI combustion modes. The model-based control technique was used to develop and validate the proposed control strategy for the fast and smooth combustion mode transition based upon the developed control-oriented engine; and an HCCI capable SI engine was designed and constructed using production ready two-step valve-train with electrical variable valve timing actuating system. Finally, smooth combustion mode transition was demonstrated on a metal engine within eight engine cycles. The Chrysler turbocharged 2.0L I4 direct injection engine was selected as the base engine for the project and the engine was modified to fit the two-step valve with electrical variable valve timing actuating system. To develop the model-based control strategy for stable HCCI combustion and smooth combustion mode transition between SI and HCCI combustion, a control-oriented real-time engine model was developed and implemented into the MSU HIL (hardware-in-the-loop) simulation environment. The developed model was used to study the engine actuating system requirement for the smooth and fast combustion mode transition and to develop the proposed mode transition control strategy. Finally, a single cylinder optical engine was designed and fabricated for studying the HCCI combustion characteristics. Optical engine combustion tests were conducted in both SI and HCCI combustion modes and the test results were used to calibrate the developed control-oriented engine model. Intensive GT-Power simulations were conducted to determine the optimal valve lift (high and low) and the cam phasing range. Delphi was selected to be the supplier for the two-step valve-train and Denso to be the electrical variable valve timing system supplier. A test bench was constructed to develop control strategies for

  17. Research on the Influence of Hydrogen and Carbon Monoxide on Methane HCCI Combustion

    Science.gov (United States)

    Sato, Susumu; Yamasaki, Yudai; Kawamura, Hideo; Iida, Norimasa

    In this research, the influence on natural gas combustion of H2 and CO was investigated by numerical calculations with elementary reactions. The investigation was carried out using the following procedures: 1. To research basic oxidation characteristics of CH4/H2/CO mixed fuel, parametric calculations for initial temperature were carried out. 2. For investigation of the effect of H2 and CO on CH4 combustion, the calculations with H2 and CO initial mole fraction variation was carried out. As a result, it was clarified that the oxidation temperature of CO was higher than that of CH4 and H2, the increase of H2 initial fraction has the effect to advance CH4 ignition timing, and increase of the CO fraction, under the condition that only CO was added, has the opposite effect of H2 addition.

  18. A Simple HCCI Engine Model for Control

    Energy Technology Data Exchange (ETDEWEB)

    Killingsworth, N; Aceves, S; Flowers, D; Krstic, M

    2006-06-29

    The homogeneous charge compression ignition (HCCI) engine is an attractive technology because of its high efficiency and low emissions. However, HCCI lacks a direct combustion trigger making control of combustion timing challenging, especially during transients. To aid in HCCI engine control we present a simple model of the HCCI combustion process valid over a range of intake pressures, intake temperatures, equivalence ratios, and engine speeds. The model provides an estimate of the combustion timing on a cycle-by-cycle basis. An ignition threshold, which is a function of the in-cylinder motored temperature and pressure is used to predict start of combustion. This model allows the synthesis of nonlinear control laws, which can be utilized for control of an HCCI engine during transients.

  19. Application of a Genetic Algorithm to the Optimization of Rate Constants in Chemical Kinetic Models for Combustion Simulation of HCCI Engines

    Science.gov (United States)

    Kim, Sang-Kyu; Ito, Kazuma; Yoshihara, Daisuke; Wakisaka, Tomoyuki

    For numerically predicting the combustion processes in homogeneous charge compression ignition (HCCI) engines, practical chemical kinetic models have been explored. A genetic algorithm (GA) has been applied to the optimization of the rate constants in detailed chemical kinetic models, and a detailed kinetic model (592 reactions) for gasoline reference fuels with arbitrary octane number between 60 and 100 has been obtained from the detailed reaction schemes for iso-octane and n-heptane proposed by Golovitchev. The ignition timing in a gasoline HCCI engine has been predicted reasonably well by zero-dimensional simulation using the CHEMKIN code with this detailed kinetic model. An original reduced reaction scheme (45 reactions) for dimethyl ether (DME) has been derived from Curran’s detailed scheme, and the combustion process in a DME HCCI engine has been predicted reasonably well in a practical computation time by three-dimensional simulation using the authors’ GTT code, which has been linked to the CHEMKIN subroutines with the proposed reaction scheme and also has adopted a modified eddy dissipation combustion model.

  20. Direct numerical simulations of ignition of a lean n-heptane/air mixture with temperature and composition inhomogeneities relevant to HCCI and SCCI combustion

    KAUST Repository

    Luong, Minh Bau

    2015-12-01

    The effects of temperature and composition stratifications on the ignition of a lean n-heptane/air mixture at three initial mean temperatures under elevated pressure are investigated using direct numerical simulations (DNSs) with a 58-species reduced mechanism. Two-dimensional DNSs are performed by varying several key parameters: initial mean temperature, T0, and the variance of temperature and equivalence ratio (T\\' and φ\\') with different T-φcorrelations. It is found that for cases with φ\\' only, the overall combustion occurs more quickly and the mean heat release rate (HRR) increases more slowly with increasing φ\\' regardless of T0. For cases with T\\' only, however, the overall combustion is retarded/advanced in time with increasing T\\' for low/high T0 relative to the negative-temperature coefficient (NTC) regime resulting from a longer/shorter overall ignition delay of the mixture. For cases with uncorrelated T-φfields, the mean HRR is more distributed over time compared to the corresponding cases with T\\' or φ\\' only. For negatively-correlated cases, however, the temporal evolution of the overall combustion exhibits quite non-monotonic behavior with increasing T\\' and φ\\' depending on T0. All of these characteristics are found to be primarily related to the 0-D ignition delays of initial mixtures, the relative timescales between 0-D ignition delay and turbulence, and the dominance of the deflagration mode during the ignition. These results suggest that an appropriate combination of T\\' and φ\\' together with a well-prepared T-φdistribution can alleviate an excessive pressure-rise rate (PRR) and control ignition-timing in homogeneous charge compression-ignition (HCCI) combustion. In addition, critical species and reactions for the ignition of n-heptane/air mixture through the whole ignition process are estimated by comparing the temporal evolution of the mean mass fractions of important species with the overall reaction pathways of n

  1. An Investigation of the Effect of Charge Inhomogeneity on the Ignition and Combustion Processes in a HCCI Engine Using Chemiluminescence Imaging

    Science.gov (United States)

    Kumano, Kengo; Yamasaki, Yudai; Iida, Norimasa

    In the HCCI (Homogeneous Charge Compression Ignition) engines, inhomogeneity in fuel distribution and temperature in the pre-mixture exists microscopically and has possibility to affect the ignition and combustion process. In this study, the effect of charge inhomogeneity in fuel distribution on the HCCI combustion process was investigated. Pressure profiles were measured and two dimensional chemiluminescence images were captured by using a framing camera with a 4-stroke optically accessible engine in order to understand the spatial distribution of the combustion. DME (di-methyl ether) was used as the test fuel. By changing the way of mixing air and fuel in the intake manifold, inhomogeneity in fuel distribution in the pre-mixture was varied. The result shows that luminescence is observed in a very short time in a large part of the combustion chamber under the homogeneous condition, while luminescence appears locally with considerable time differences under the inhomogeneous condition. It is also shown that the local luminescence durations are almost the same under both conditions.

  2. The Research of Homogeneous Charge Compression Ignition (HCCI) Combustion%均质压燃式(HCCI)燃烧的研究

    Institute of Scientific and Technical Information of China (English)

    王大兴; 张欣; 刘建华

    2002-01-01

    均质压燃式(HCCI)燃烧方式是目前内燃机燃烧领域的研究热点.HCCI燃烧是以预混合燃烧和低温反应为特征的燃烧方式.采用HCCI燃烧方式可以同时有效降低柴油机的NOx和碳烟排放,并提高柴油机的循环热效率.HCCI发动机通常工作在高空燃比和较低的压缩比条件下,工作范围较小,高负荷时功率输出不足."双模式"HCCI发动机是解决上述问题的有效途径,并成为近期HCCI发动机研究中的热点.

  3. Research of Controlling of Homogeneous Charge Compression Ignition (HCCI) Combustion Procedure%均质压燃(HCCI)燃烧过程控制方式的研究

    Institute of Scientific and Technical Information of China (English)

    卢美秀; 张欣; 李从心

    2004-01-01

    均质压燃(HCCI)燃烧方式是目前内燃机燃烧领域的研究焦点.因HCCI发动机的燃烧过程主要由可燃混合气的化学动力学所控制,故很难在全负荷范围内控制它的着火时刻和燃烧放热率.因此,HCCI燃烧过程的控制成为HCCI研究热点.本文根据一些控制HCCI发动机燃烧过程的研究结果对其进行阐述.

  4. Flex Fuel Optimized SI and HCCI Engine

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guoming; Schock, Harold; Yang, Xiaojian; Huisjen, Andrew; Stuecken, Tom; Moran, Kevin; Zhen, Ron; Zhang, Shupeng

    2013-09-30

    The central objective of the proposed work is to demonstrate an HCCI (homogeneous charge compression ignition) capable SI (spark ignited) engine that is capable of fast and smooth mode transition between SI and HCCI combustion modes. The model-based control technique was used to develop and validate the proposed control strategy for the fast and smooth combustion mode transition based upon the developed control-oriented engine; and an HCCI capable SI engine was designed and constructed using production ready two-step valve-train with electrical variable valve timing actuating system. Finally, smooth combustion mode transition was demonstrated on a metal engine within eight engine cycles. The Chrysler turbocharged 2.0L I4 direct injection engine was selected as the base engine for the project and the engine was modified to fit the two-step valve with electrical variable valve timing actuating system. To develop the model-based control strategy for stable HCCI combustion and smooth combustion mode transition between SI and HCCI combustion, a control-oriented real-time engine model was developed and implemented into the MSU HIL (hardware-in-the-loop) simulation environment. The developed model was used to study the engine actuating system requirement for the smooth and fast combustion mode transition and to develop the proposed mode transition control strategy. Finally, a single cylinder optical engine was designed and fabricated for studying the HCCI combustion characteristics. Optical engine combustion tests were conducted in both SI and HCCI combustion modes and the test results were used to calibrate the developed control-oriented engine model. Intensive GT-Power simulations were conducted to determine the optimal valve lift (high and low) and the cam phasing range. Delphi was selected to be the supplier for the two-step valve-train and Denso to be the electrical variable valve timing system supplier. A test bench was constructed to develop control strategies for

  5. Combustion Characteristics of Sprays

    Science.gov (United States)

    1989-08-01

    regarded by implication or otherwise, or in any way licensing the holder or any other person or corporation, or conveying any rights or permission to...00 _’N 1. TI TLE inctuat Security CZaaafication5 Combustion Characteristics of Sprays 12. PERSONAL AUTHOR(S) Sohrab, Siavash H. 13& TYPE OF REPORT...to ?!HF of rich butane/air 3unsen flames. .lso, the rotacion speed and :he oerodic temDeracure fluc:uations of rotacfng ?HF are examined. :’!naily

  6. 二甲醚均质混合压燃燃烧数值模拟研究%Combustion Numerical Simulation of DME HCCI

    Institute of Scientific and Technical Information of China (English)

    邓航; 邓惜仁; 吴先焕

    2016-01-01

    In this paper, the simulation study on dimethyl ether HCCI combustion is carried out by using the large-scale chemical reaction kinetics software CHEMKIN, combined with the detailed chemical kinetics model of DME. The combustion chemical kinetics mechanism of DME is investigated in theory. And the influences of boundary conditions on DME HCCI combustion are analyzed. The results show that the maximum pressure and the maximum temperature in the cylinder are increased with the increase of the intake air temperature, excess air coefficient and the increase of initial pressure.%文章利用大型化学反应动力学软件CHEMKIN结合二甲醚详细化学反应动力模型,对二甲醚的HCCI燃烧进行了模拟研究,从理论上研究探讨二甲醚的HCCI燃烧机理,构建了二甲醚HCCI反应动力学的简化模型,并研究了边界条件对二甲醚HCCI燃烧的影响。结果表明:随着进气温度的升高、过量空气系数的减小、初始压力的增加,缸内的最高压力升高,最大燃烧温度上升。

  7. Combustion Characteristics of C5 Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation

    KAUST Repository

    Park, Sungwoo

    2015-10-27

    C5 alcohols are considered alternative fuels because they emit less greenhouse gases and fewer harmful pollutants. In this study, the combustion characteristics of 2-methylbutanol (2-methyl-1-butanol) and isopentanol (3-methyl-1-butanol) and their mixtures with primary reference fuels (PRFs) were studied using a detailed chemical kinetic model obtained from merging previously published mechanisms. Ignition delay times of the C5 alcohol/air mixtures were compared to PRFs at 20 and 40 atm. Reaction path analyses were conducted at intermediate and high temperatures to identify the most influential reactions controlling ignition of C5 alcohols. The direct relation graph with expert knowledge methodology was used to eliminate unimportant species and reactions in the detailed mechanism, and the resulting skeletal mechanism was tested at various homogeneous charge compression ignition (HCCI) engine combustion conditions. These simulations were used to investigate the heat release characteristics of the methyl-substituted C5 alcohols, and the results show relatively strong reactions at intermediate temperatures prior to hot ignition. C5 alcohol blending in PRF75 in HCCI combustion leads to a significant decrease of low-temperature heat release (LTHR) and a delay of the main combustion. The heat release features demonstrated by C5 alcohols can be used to improve the design and operation of advanced engine technologies.

  8. 废气再循环和进气加热实现汽油机HCCI燃烧的性能对比%Performance Comparison of Gasoline Engine HCCI Combustion Approached by EGR and Intake Heating

    Institute of Scientific and Technical Information of China (English)

    虞卫飞; 谢辉; 李乐; 陈韬; 赵华

    2012-01-01

    废气再循环和进气加热是实现汽油机HCCI燃烧的两种不同方式,其对HCCI燃烧性能的影响也不同,为此,在同一台汽油机上分别采用废气再循环和进气加热实现HCCI燃烧,并分析了其在HCCI燃烧性能上存在差异的机理.试验结果表明,相对于进气加热,废气再循环的工质比热容高,但由于稀释比较小,使得其工质总热容反而低,从而缸内燃烧温度高.废气再循环HCCI燃烧的未燃HC排放比进气加热的排放值低41% ~ 59%;NOx排放是后者的2 ~ 20倍;而CO排放与负荷有关;其燃烧效率比迸气加热HCCI的值高0.8%~14%.然而,由于进气加热的PMEP低,缸内工质比热比大,传热损失小,最终使得进气加热HCCI燃烧的ISFC比废气再循环HCCI燃烧的值低6.6%~16.4%.%Exhaust gas recirculation(EGR)and intake heating are two different approaches for gasoline engine to achieving homogeneous charge compression ignition (HCCI) combustion and have different performances on HCCI combustion. Therefore, experiments were carried out on a single-cylinder gasoline engine with HCCI combustion using EGR and intake heating, respectively, to study the different performance mechanisms of the two approaches on HCCI combustion. The experimental results show that, compared with the HCCI combustion with intake heating, the specific heat of charge with EGR is higher. However, lower dilution ratio leads to lower total specific heat of charge , which results in higher in-cylinder combustion temperature. The unburned hydrocarbons (UHC)emission generated by HCCI combustion with EGR is 41%?9% lower than that by HCCI combustion using intake heating. NO, emission of the former is 2?0 times that of the latter, and the CO emission depends on the IMEP. The combustion efficiency of HCCI combustion with EGR is 0.8%?4% higher than that of HCCI combustion with intake heating. However, due to lower pumping mean effective pressure, higher specific heat ratio of

  9. Combustion characteristics of turbo charged DISI-engines

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmeyer, Henrik

    2012-07-01

    In spite of progress in the development of alternative powertrain systems and energy sources, the internal combustion and all its derivates still are and will be the main powertrain for automobiles. In SI-engines, several approaches compete with each other like the controlled auto ignition (CAI or HCCI), throttle-free load control using variable valvetrains, stratified mixture formation with lean engine operation or highly turbo charged downsizing concepts all combined with gasoline direct injection. The presented work makes a contribution for a deeper understanding of the combustion process of a turbo charged direct injection engine operating with external EGR as well as lean stratified mixture. Using detailed test bench investigations and introducing a new optical measurement tool, the combustion process is described in detail focusing on the occurrence of non-premixed combustion phenomena. The influence of engine parameters like global and local air-/fuel ratio, external EGR and fuel rail pressure as well as the influence of fuel parameters are discussed giving a characterization of the combustion process of stratified engine operation. Furthermore, the influences of non-inert exhaust gas components on engine knock tendency are investigated using external EGR with an EGR catalyst. Opposing the results to numerical analysis, combustion characteristics of turbo charged DISI-engines are presented. (orig.)

  10. Nonlinear Model Predictive Control of A Gasoline HCCI Engine Using Extreme Learning Machines

    OpenAIRE

    Janakiraman, Vijay Manikandan; Nguyen, XuanLong; Assanis, Dennis

    2015-01-01

    Homogeneous charge compression ignition (HCCI) is a futuristic combustion technology that operates with a high fuel efficiency and reduced emissions. HCCI combustion is characterized by complex nonlinear dynamics which necessitates a model based control approach for automotive application. HCCI engine control is a nonlinear, multi-input multi-output problem with state and actuator constraints which makes controller design a challenging task. Typical HCCI controllers make use of a first princi...

  11. Homogeneous charge compression ignition (HCCI) - A comparison with spark ignition (SI) operation

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Magnus

    1997-08-01

    Homogeneous Charge Compression Ignition (HCCI) is the third alternative for combustion in engines. Here a homogeneous premixed charge is used as in a spark ignited engine but the charge is compressed to auto-ignition as in a diesel. The characteristics of HCCI was compared to spark ignition (SI) using a 1.6 liter single cylinder engine. Three different fuels were used; isooctane, ethanol and natural gas. HCCI could be used with all three fuels in a single cylinder engine with a fixed compression ratio. Some remarkable results were noted in the experiments. The indicated efficiency of HCCI was much better than for SI operation. The gross indicated efficiency showed values at 50% for the richer cases. This means that the fuel consumption at part load would be reduced to the half compared to SI operation. Very little NO{sub x} was generated with HCCI, only a few ppm. With isooctane, it ranged from 4 to below 1 ppm and with ethanol even lower values. However, HCCI generated more HC and CO. Operation was noisier with HCCI than with SI. Stable and efficient operation with HCCI could be obtained with {lambda} = 3.5 to 9 using isooctane, 3.5 to 6.5 using ethanol, and 2.5 to 3.5 using natural gas. Cycle to cycle variation of combustion was very low. Isooctane could be operated unthrottled without preheating. The selection of the high compression ratio, 21:1, was dependent on the high octane number for natural gas. The attainable IMEP was 5 bar. The limit to make higher IMEP was the rate of combustion. At IMEP 5 bar the main combustion, 10-90% burn duration, took place in less than 2 crank angle degrees (CAD). This is extremely fast and gives very high rate of pressure rise, which leads to noisy operation and high loads on the engine. The lean limit was given by unstable combustion with cycle to cycle variation of combustion, and with high emissions of unburned hydrocarbons and carbon monoxide Examination paper. 15 refs, 38 figs, 1 tab

  12. Performance and emission study on DICI and HCCI engine using raw pongamia oil and diesel

    Directory of Open Access Journals (Sweden)

    Mani Venkatraman

    2016-01-01

    Full Text Available The present work investigates the performance and emission characteristics of pongamia oil and diesel fuelled direct injection compression ignition (DICI and homogeneous charge compression ignition (HCCI engine. The primary objective of the work is to investigate the feasibility of application of unmodified pongamia oil in Diesel engine and to estimate the maximum fraction of diesel fuel replaced by the neat pongamia oil. This investigation also deals with the HCCI operation using unmodified pongamia oil. In DICI mode the neat pongamia oil is admitted into the engine in the form of pongamia oil and diesel blends. The blend that offers highest diesel replacement is considered as the test blend and it is tested further to find its maximum possible brake thermal efficiency by changing the engine operating parameters. The selected maximum blend is then tested in the new setting of the engine to determine the maximum possible performance and emission characteristics. The conventional emissions of DICI engine such as NO and smoke are disappeared in the homogeneous charge compression ignition mode of operation. The HCCI engine tested in the present work is fuelled by 40% neat pongamia oil and 60% diesel fuel through direct injection and vapour induction, respectively. The ignition or combustion phasing of the HCCI operation is carried out by the exhaust gas recirculation method. The amount of exhaust gas re-circulation governs the timing of combustion. The results of the experiments show that the neat pongamia oil performed well in HCCI mode and offered approximately ten times lower NO and smoke emission. Finally, the results of the DICI mode and HCCI mode are compared with each other to reveal the truths of neat pongamia oil in heterogeneous and homogeneous combustion.

  13. Influence of Operating Parameters on Methanol HCCI Combustion Stability and Cycle-to-cycle Variation%运行参数对甲醇 HCCI 燃烧稳定性和循环变动的影响

    Institute of Scientific and Technical Information of China (English)

    潘江如; 张春化; 鲁亚云

    2014-01-01

    为研究进气温度、过量空气系数和发动机转速对甲醇HCCI燃烧循环变动和燃烧稳定性的影响,在1台改造的试验发动机上进行相关的试验。试验结果表明:随着进气温度的升高,循环变动变大,最高燃烧压力的分布较为集中;循环变动系数对过量空气系数较为敏感,随着过量空气系数的增大,循环变动变大,最高燃烧压力的分布较为分散;随着转速的增大,循环变动变小,最高燃烧压力的平均值变大,最高燃烧压力分布集中,对于甲醇而言,进气温度为160℃,过量空气系数为2时,n=1300 r/min是较优的转速。%In order to study the influences of intake temperature ,excess air coefficient and engine speed on methanol HCCI combustion stability and cycle-to-cycle variation ,the relevant tests were carried out on a retrofit engine .The results show that the cycle-to-cycle variation increases and the distribution of maximum combustion pressure concentrates with the increase of in-take temperature .The excess air coefficient is more sensitive to the coefficient of cycle-to-cycle variation .With the increase of excess air coefficient , the cycle-to-cycle variation decreases and the distribution of maximum combustion pressure scatters . With the increase of engine speed ,the cycle-to-cycle variation decreases ,the mean value of maximum combustion pressure in-creases and its distribution concentrates .For the methanol fuel ,1 300 r/min is the optimal speed at 160 ℃ of intake tempera-ture and when the excess air coefficient is 2 .

  14. Application Performance Investigation of HCCI Combustion Technique%HCCI燃烧技术应用性能研究

    Institute of Scientific and Technical Information of China (English)

    任勇; 陈浩; 潘磊

    2014-01-01

    均质压燃(HCCI)是一种全新的燃烧方式,它能够有效地提高发动机的燃烧热效率,降低NOx和碳烟的排放.阐述了HCCI燃烧的特点、HCCI燃烧技术的优点、需要解决的技术问题,介绍了将HCCI燃烧技术应用到汽油机、柴油机上的一些方法,最后对HCCI燃烧技术的应用前景进行了展望.

  15. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    Energy Technology Data Exchange (ETDEWEB)

    John Pratapas; Daniel Mather; Anton Kozlovsky

    2007-03-31

    analysis of test results indicates that hydrogen enhanced natural gas HCCI (versus neat natural gas HCCI at comparable stoichiometry) had the following characteristics: (1) Substantially lower intake temperature needed for stable HCCI combustion; (2) Inconclusive impact on engine BMEP and power produced; (3) Small reduction in the thermal efficiency of the engine; (4) Moderate reduction in the unburned hydrocarbons in the exhaust; (5) Slight increase in NOx emissions in the exhaust; (6) Slight reduction in CO2 in the exhaust; and (7) Increased knocking at rich stoichiometry. The major accomplishments and findings from the project can be summarized as follows: (1) A model was calibrated for accurately predicting heat release rate and peak pressures for HCCI combustion when operating on hydrogen and natural gas blends. (2) A single cylinder research engine was thoroughly mapped to compare performance and emissions for micro-pilot natural gas compression ignition, and HCCI combustion for neat natural gas versus blends of natural gas and hydrogen. (3) The benefits of using hydrogen to extend, up to a limit, the stable operating window for HCCI combustion of natural gas at higher intake pressures, leaner air to fuel ratios or lower inlet temperatures was documented.

  16. Combustion in Homogeneous Charge Compression Ignition Engines: Experiments and Detailed Chemical Kinetic Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Flowers, D L

    2002-06-07

    Homogeneous charge compression ignition (HCCI) engines are being considered as an alternative to diesel engines. The HCCI concept involves premixing fuel and air prior to induction into the cylinder (as is done in current spark-ignition engine) then igniting the fuel-air mixture through the compression process (as is done in current diesel engines). The combustion occurring in an HCCI engine is fundamentally different from a spark-ignition or Diesel engine in that the heat release occurs as a global autoignition process, as opposed to the turbulent flame propagation or mixing controlled combustion used in current engines. The advantage of this global autoignition is that the temperatures within the cylinder are uniformly low, yielding very low emissions of oxides of nitrogen (NO{sub x}, the chief precursors to photochemical smog). The inherent features of HCCI combustion allows for design of engines with efficiency comparable to, or potentially higher than, diesel engines. While HCCI engines have great potential, several technical barriers exist which currently prevent widespread commercialization of this technology. The most significant challenge is that the combustion timing cannot be controlled by typical in-cylinder means. Means of controlling combustion have been demonstrated, but a robust control methodology that is applicable to the entire range of operation has yet to be developed. This research focuses on understanding basic characteristics of controlling and operating HCCI engines. Experiments and detailed chemical kinetic simulations have been applied to the characterize some of the fundamental operational and design characteristics of HCCI engines. Experiments have been conducted on single and multi-cylinder engines to investigate general features of how combustion timing affects the performance and emissions of HCCI engines. Single-zone modeling has been used to characterize and compare the implementation of different control strategies. Multi

  17. A parametric study on the emissions from an HCCI alternative combustion engine resulting from the auto-ignition of primary reference fuels

    Energy Technology Data Exchange (ETDEWEB)

    Machrafi, Hatim; Cavadias, Simeon; Amouroux, Jacques [UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris, 11, rue de Pierre et Marie Curie, 75005 Paris (France)

    2008-08-15

    The homogeneous charge compression ignition is an alternative combustion technology that can reduce automobile pollution, provided that the exhaust emission can be controlled. A parametric study can be useful in order to gain more understanding in the emission reduction possibilities via this new combustion technology. For this purpose, the inlet temperature, the equivalence ratio and the compression ratio are changed, respectively, from 30 to 70{sup o}C, 0.28 to 0.41 and 6 to 14. Also the diluting, thermal and chemical effects of exhaust gas recirculation were studied. The emission of CO, CO{sub 2}, O{sub 2} and hydrocarbons has been measured using primary reference fuels. It appears that an increase in the inlet temperature, the EGR temperature, the equivalence ratio and the compression ratio results into a decrease of the emissions of CO and the hydrocarbons of up to 75%. The emission of CO{sub 2} increased, however, by 50%. The chemical parameters showed more complicated effects, resulting into a decrease or increase of the emissions, depending on whether the overall reactivity increased or not. If the reactivity increased, generally, the emissions of CO and hydrocarbons increased, while that of CO{sub 2} increased. The increase of CO{sub 2} emissions could be compensated by altering the compression ratio and the EGR parameters, making it possible to control the emission of the HCCI engine. (author)

  18. Auto-Ignition of Iso-Stoichiometric Blends of Gasoline-Ethanol-Methanol (GEM) in SI, HCCI and CI Combustion Modes

    KAUST Repository

    Waqas, Muhammad

    2017-03-28

    Gasoline-ethanol-methanol (GEM) blends, with constant stoichiometric air-to-fuel ratio (iso-stoichiometric blending rule) and equivalent to binary gasoline-ethanol blends (E2, E5, E10 and E15 in % vol.), were defined to investigate the effect of methanol and combined mixtures of ethanol and methanol when blended with three FACE (Fuels for Advanced Combustion Engines) Gasolines, I, J and A corresponding to RON 70.2, 73.8 and 83.9, respectively, and their corresponding Primary Reference Fuels (PRFs). A Cooperative Fuel Research (CFR) engine was used under Spark Ignition and Homogeneous Charge Compression Ignited modes. An ignition quality tester was utilized in the Compression Ignition mode. One of the promising properties of GEM blends, which are derived using the iso-stoichiometric blending rule, is that they maintain a constant octane number, which has led to the introduction of methanol as a drop-in fuel to supplement bio-derived ethanol. A constant RON/HCCI fuel number/derived Research octane number property was observed in all three combustion modes for high RON fuels, but for low RON fuels, the iso-stoichiometric blending rule for constant octane number did not appear to be valid. The chemical composition and octane number of the base fuel also influenced the behavior of the GEM blends under different conditions.

  19. 甲醇燃料对实现HCCI燃烧小负荷工况的实验研究%Experimental Research on the Realization of HCCI Low-load Combustion with Methanol

    Institute of Scientific and Technical Information of China (English)

    叶坦

    2015-01-01

    近年来国内外对内燃机燃料的研究日趋深入,含氧燃料成为重要的研究课题。甲醇燃料相对于乙醇和汽油燃料表现出了较好的自燃性能,并且甲醇有较高的耐废气能力,这些对HCCI小负荷燃烧的燃油经济性非常有利。通过实验对比甲醇和汽油燃料在废气管理过程中的出现的问题,研究甲醇对小负荷HCCI燃烧拓展的影响。研究发现甲醇燃料对HCCI小负荷着火燃烧有很大的好处,而且甲醇燃料的使用燃烧效率得到提高以后,可以大幅降低HC和CO的排放,但是对于HCCI燃烧运行的负荷边界而言,更容易引起发动机粗暴燃烧。%With researches on the fuel of internal combustion engine are getting further home and abroad in recent years,oxygenated fuel has become an important research object.Compared with ethanol and gasoline,methanol shows the better spontaneous combustion per-formance and higher exhausts tolerance ability which is favorable to the fuel of economic HCCI combustion at low load condition. Through experimental comparisons of problems in exhausts treatment between methanol and gasoline,the effects of methanol on HCCI low-load combustion development have been studied.Research shows that methanol fuels do much promotion to HCCI low-load com-bustion ignition and reduce the emission of HC and CO greatly with the improvement of methanol fuel combustion efficiency while it’s more likely to cause rough combustion of the engine on the operating load boundary of HCCI combustion.

  20. Experimental Study on Dimethyl Ether Combustion Process in Homogeneous Charge Compression Ignition Mode

    Institute of Scientific and Technical Information of China (English)

    郑尊清; 史春涛; 尧命发

    2004-01-01

    Experimental study on homogeneous charge compression ignition (HCCI) combustion process was carried out on a single-cylinder direct injection diesel engine fueled with dimethyl ether(DME). The influence of inert gas CO2 on the ignition and combustion process was investigated. The research results indicate that because of the high cetane number of DME, the stable HCCI operating range is quite narrow while the engine has a high compression ratio. The HCCI operating range can be largely extended when the inert gas is inducted into the charging air. HCCI combustion of DME presents remarkable characteristic of two-stage combustion process. As the concentration of inert gas increases, the ignition timing of the first combustion stage delays, the peak heat release rate decreases, and the combustion duration extends. Inducting inert gas into charging air cannot make the combustion and heat release of DME occur at a perfect crank angle position. Therefore,to obtain HCCI operation for the fuel with high cetane number,other methods such as reducing engine compression ratio should be adopted. Emission results show that under HCCI operation, a nearly zero NOx emission can be obtained with no smoke emissions. But the HC and CO emissions are high, and both rise with the increase of the concentration of inert gases.

  1. HCCI Engine Optimization and Control

    Energy Technology Data Exchange (ETDEWEB)

    Rolf D. Reitz

    2005-09-30

    The goal of this project was to develop methods to optimize and control Homogeneous-Charge Compression Ignition (HCCI) engines, with emphasis on diesel-fueled engines. HCCI offers the potential of nearly eliminating IC engine NOx and particulate emissions at reduced cost over Compression Ignition Direct Injection engines (CIDI) by controlling pollutant emissions in-cylinder. The project was initiated in January, 2002, and the present report is the final report for work conducted on the project through December 31, 2004. Periodic progress has also been reported at bi-annual working group meetings held at USCAR, Detroit, MI, and at the Sandia National Laboratories. Copies of these presentation materials are available on CD-ROM, as distributed by the Sandia National Labs. In addition, progress has been documented in DOE Advanced Combustion Engine R&D Annual Progress Reports for FY 2002, 2003 and 2004. These reports are included as the Appendices in this Final report.

  2. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    Energy Technology Data Exchange (ETDEWEB)

    Pratapas, John; Mather, Daniel; Kozlovsky, Anton

    2013-03-31

    analysis of test results indicates that hydrogen enhanced natural gas HCCI (versus neat natural gas HCCI at comparable stoichiometry) had the following characteristics: • Substantially lower intake temperature needed for stable HCCI combustion • Inconclusive impact on engine BMEP and power produced, • Small reduction in the thermal efficiency of the engine, • Moderate reduction in the unburned hydrocarbons in the exhaust, • Slight increase in NOx emissions in the exhaust, • Slight reduction in CO2 in the exhaust. • Increased knocking at rich stoichiometry The major accomplishments and findings from the project can be summarized as follows: 1. A model was calibrated for accurately predicting heat release rate and peak pressures for HCCI combustion when operating on hydrogen and natural gas blends. 2. A single cylinder research engine was thoroughly mapped to compare performance and emissions for micro-pilot natural gas compression ignition, and HCCI combustion for neat natural gas versus blends of natural gas and hydrogen.

  3. Direct numerical simulations of exhaust gas recirculation effect on multistage autoignition in the negative temperature combustion regime for stratified HCCI flow conditions by using H2O2 addition

    Science.gov (United States)

    El-Asrag, Hossam A.; Ju, Yiguang

    2013-04-01

    Direct numerical simulations (DNSs) of a stratified flow in a homogeneous compression charge ignition (HCCI) engine are performed to investigate the exhaust gas recirculation (EGR) and temperature/mixture stratification effects on the autoignition of synthetic dimethyl ether (DME) in the negative temperature combustion region. Detailed chemistry for a DME/air mixture is employed and solved by a hybrid multi-time scale (HMTS) algorithm to reduce the computational cost. The effect of ? to mimic the EGR effect on autoignition are studied. The results show that adding ? enhances autoignition by rapid OH radical pool formation (34-46% reduction in ignition delay time) and changes the ignition heat release rates at different ignition stages. Sensitivity analysis is performed and the important reactions pathways affecting the autoignition are specified. The DNS results show that the scales introduced by thermal and mixture stratifications have a strong effect after the low temperature chemistry (LTC) ignition especially at the locations of high scalar dissipation rates. Compared to homogenous ignition, stratified ignitions show similar first autoignition delay times, but 18% reduction in the second and third ignition delay times. The results also show that molecular transport plays an important role in stratified low temperature ignition, and that the scalar mixing time scale is strongly affected by local ignition in the stratified flow. Two ignition-kernel propagation modes are observed: a wave-like, low-speed, deflagrative mode and a spontaneous, high-speed, ignition mode. Three criteria are introduced to distinguish these modes by different characteristic time scales and Damkhöler numbers using a progress variable conditioned by an ignition kernel indicator. The low scalar dissipation rate flame front is characterized by high displacement speeds and high mixing Damkhöler number. The proposed criteria are applied successfully at the different ignition stages and

  4. Numerical simulation and validation of SI-CAI hybrid combustion in a CAI/HCCI gasoline engine

    Science.gov (United States)

    Wang, Xinyan; Xie, Hui; Xie, Liyan; Zhang, Lianfang; Li, Le; Chen, Tao; Zhao, Hua

    2013-02-01

    SI-CAI hybrid combustion, also known as spark-assisted compression ignition (SACI), is a promising concept to extend the operating range of CAI (Controlled Auto-Ignition) and achieve the smooth transition between spark ignition (SI) and CAI in the gasoline engine. In this study, a SI-CAI hybrid combustion model (HCM) has been constructed on the basis of the 3-Zones Extended Coherent Flame Model (ECFM3Z). An ignition model is included to initiate the ECFM3Z calculation and induce the flame propagation. In order to precisely depict the subsequent auto-ignition process of the unburned fuel and air mixture independently after the initiation of flame propagation, the tabulated chemistry concept is adopted to describe the auto-ignition chemistry. The methodology for extracting tabulated parameters from the chemical kinetics calculations is developed so that both cool flame reactions and main auto-ignition combustion can be well captured under a wider range of thermodynamic conditions. The SI-CAI hybrid combustion model (HCM) is then applied in the three-dimensional computational fluid dynamics (3-D CFD) engine simulation. The simulation results are compared with the experimental data obtained from a single cylinder VVA engine. The detailed analysis of the simulations demonstrates that the SI-CAI hybrid combustion process is characterised with the early flame propagation and subsequent multi-site auto-ignition around the main flame front, which is consistent with the optical results reported by other researchers. Besides, the systematic study of the in-cylinder condition reveals the influence mechanism of the early flame propagation on the subsequent auto-ignition.

  5. Pulsating combustion - Combustion characteristics and reduction of emissions

    Energy Technology Data Exchange (ETDEWEB)

    Lindholm, Annika

    1999-11-01

    In the search for high efficiency combustion systems pulsating combustion has been identified as one of the technologies that potentially can meet the objectives of clean combustion and good fuel economy. Pulsating combustion offers low emissions of pollutants, high heat transfer and efficient combustion. Although it is an old technology, the interest in pulsating combustion has been renewed in recent years, due to its unique features. Various applications of pulsating combustion can be found, mainly as drying and heating devices, of which the latter also have had commercial success. It is, however, in the design process of a pulse combustor, difficult to predict the operating frequency, the heat release etc., due to the lack of a well founded theory of the phenomenon. Research concerning control over the combustion process is essential for developing high efficiency pulse combustors with low emissions. Natural gas fired Helmholtz type pulse combustors have been the experimental objects of this study. In order to investigate the interaction between the fluid dynamics and the chemistry in pulse combustors, laser based measuring techniques as well as other conventional measuring techniques have been used. The experimental results shows the possibilities to control the combustion characteristics of pulsating combustion. It is shown that the time scales in the large vortices created at the inlet to the combustion chamber are very important for the operation of the pulse combustor. By increasing/decreasing the time scale for the large scale mixing the timing of the heat release is changed and the operating characteristics of the pulse combustor changes. Three different means for NO{sub x} reduction in Helmholtz type pulse combustors have been investigated. These include exhaust gas recirculation, alteration of air/fuel ratio and changed inlet geometry in the combustion chamber. All used methods achieved less than 10 ppm NO{sub x} emitted (referred to stoichiometric

  6. 乙醇汽油混合燃料直喷均质压燃爆震模型和试验研究%Experimental studies on knocking characteristics of DI-HCCI with gasoline/ethanol fuels

    Institute of Scientific and Technical Information of China (English)

    邓俊; 史现; 刘寅童; 吴志军; 李理光

    2013-01-01

    Knocking characteristics were investigated by using engine bench tests for a combustion of DI-HCCI (direct-injection homogeneous charge compression ignition) with blend fuels of ethanol and gasoline. Some improvements were done to a traditional two-cylinder diesel engine in fuel supply system, ignition system, and inlet and exhaust system. A knock model was established according to the engine bench tests and the cylinder pressure signals to describe ethanol and gasoline HCCI combustion. Knock intensity (KI) was drawn from the model and then was measured in the tests. The results show that the average KI and the knock probability signiifcantly decrease with the blending ratio of ethanol and gasoline, i.e. the percentage of ethanol increases, while the knock starting phase retards. Knock boundaries also narrow down with high blending ratio, while the upper and lower boundaries move towards each other. Those results could lead to the development of better fuel injection strategies.%为研究直接喷射(DI)式均质压燃(HCCI)爆震特性,进行了台架试验。改造了一台传统双缸柴油机的供油系统、点火系统、进排气机构,使其具有缸内直喷乙醇汽油混合燃料HCCI燃烧模式。根据该发动机台架的特点与缸压信号特征,建立了描述乙醇汽油HCCI燃烧的爆震模型,从模型中提取了爆震强度(KI),并进行了试验测量。结果表明:随乙醇在混合燃料中体积分数的升高,平均KI和爆震概率均有降低,爆震始点推后;爆震工况的当量比范围变窄,爆震工况上下边界互相靠拢。该结果有利于提出更合理的发动机喷射控制策略。

  7. Combustion characteristics of bamboo-biochars.

    Science.gov (United States)

    Liu, Zhijia; Fei, Benhua; Jiang, Zehui; Liu, Xing'e

    2014-09-01

    Combustion characteristics of biomass are very important to directly utilize as an energy resource. Bamboo was carbonized using a XD-1200N muffle furnace in the nitrogen environment and its combustion characteristics were investigated. Results showed that bamboo-biochars had better combustion characteristics compared to bamboo materials, such as a lower content of moisture and volatiles, a higher energy density, HHV and EHC, a lower H/C and O/C ratios and a shorter TTI. Characteristic peak of bamboo-biochars shifted to higher temperature in thermal decomposition process, indicating a more steady-state burning and a higher combustion efficiency. Bamboo-biochars had a low content of S and N, which was helpful to decrease pollutant emissions. A higher content of K and Na was observed in the ash of bamboo-biochars, resulting in slagging, fouling, corrosion and agglomeration. The data from this research will be very helpful to efficiently design and operate its combustion systems.

  8. 异辛烷、乙醇及其混合燃料HCCI燃烧的试验研究和分析%Experimental Study and Analysis on HCCI Combustion of Iso-Octane, Ethanol and Their Blend

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    在一台改制的发动机上进行了异辛烷、乙醇及其混合燃料HCCI燃烧的研究.发动机性能用缸内压力评估,研究用的参数包括放热率、平均指示压力和热效率.试验结果表明,乙醇着火时刻早于异辛烷;在乙醇中加入异辛烷可以推迟着火,并导致平均指示压力和热效率的降低;对某种特定燃料,HCCI燃烧的发生主要取决于进气充量温度,初始充量温度的增加将导致HCCI燃烧提前;充量温度低或发动机转速低时,混合气形成质量差,对HCCI燃烧有不良影响;指示热效率为30%~43%,其值高于火花点火发动机;预燃室的存在有利于稳定的HCCI燃烧;超稀充量运行可以显著降低NOx排放.%This paper investigates homogeneous charge compression ignition (HCCI) combustion on a modified engine fuelled with iso-octane, ethanol and iso-octane-ethanol blend. The engine performances are evaluated based on in-cylinder measured pressure. The parameters studied include heat-release rate (HRR), indicated mean effective pressure (IMEP) and indicated thermal efficiency. The experimental results demonstrate that the combustion for ethanol occurs ahead of that for iso-octane. The addition of iso-octane to ethanol retards the on-set of combustion and subsequently leads to a reduction of the IMEP and indicated thermal efficiency. For a particular fuel, the combustion depends mainly on the intake charge temperature and any increase in the initial charge temperature leads to advance in combustion. At lower charge temperatures and engine speeds, the fuel-air mixtures' quality of is poor, resulting in a poor combustion. The indicated thermal efficiency is 30% to 43%, better than those of typical SI engines. The presence of pre-chamber is advantageous to stable HCCI operation. Operation with ultra-lean mixture reduces engine-out NOx emissions significantly.

  9. The Combustion Process Analysis of HCCI Mode of Diesel Engine Fueled with Methanol/Dimethyl Ether%醇醚双燃料均质压缩燃烧过程分析

    Institute of Scientific and Technical Information of China (English)

    闫妍; 张煜盛; 孟忠伟; 吴怡

    2013-01-01

    A multi-dimensional model of methanol / DME dual fuel HCCI engine was established with the consideration of inlet port, exhaust port, and internal asymmetric structure of combustion chamber. The results showed that the multi-dimensional model could predict the cylinder pressure, temperature, the fuel concentration and ignition timing. There were two high temperature regions in HCCI combustion process, the left lower bottom and the right upper edge of the cylinder, the low-temperature reaction firstly started from these regions. The low-temperature reaction started when cylinder average temperature was about 900K , the high-temperature reaction started when cylinder average temperature was about HOOK.%建立了甲醇/二甲醚HCCI发动机燃烧与排放的多维数学模型.模型考虑了进排气道及燃烧室内部不对称结构.利用CFD软件FLUENT耦合双燃料简化动力学模型,对二甲醚/甲醇发动机的HCCI燃烧过程进行了模拟计算.结果表明,多维模型能够较好地预测缸内压力、温度、物质浓度随曲轴转角的变化过程和着火时刻.双燃料HCCI燃烧过程中有2个高温核心,分别是气缸左下底部和右上方边缘地带的两个区域,低温反应最早从这2个部位开始向缸内其他部位延伸.缸内平均温度达到900K左右开始低温反应,1100 K左右开始高温反应.

  10. An experiment study of homogeneous charge compression ignition combustion and emission in a gasoline engine

    Directory of Open Access Journals (Sweden)

    Zhang Jianyong

    2014-01-01

    Full Text Available Homogenous charge compression ignition (HCCI technology has exhibited high potential to reduce fuel consumption and NOx emissions over normal spark ignition engines significantly. Optimized kinetic process (OKP technology is implemented to realize HCCI combustion in a port fuel injection gasoline engine. The combustion and emission characteristics are investigated with variation of intake air temperature, exhaust gas recirculation (EGR rate and intake air pressure. The results show that intake air temperature has great influence on HCCI combustion characteristic. Increased intake air temperature results in advance combustion phase, shorten combustion duration, and lower indicated mean effective pressure (IMEP. Increased EGR rate retards combustion start phase and prolongs combustion duration, while maximum pressure rising rate and NOx emission are reduced with increase of EGR rate. In the condition with constant fuel flow quantity, increased air pressure leads to retarded combustion phase and lower pressure rising rate, which will reduce the engine knocking tendency. In the condition with constant air fuel ratio condition, fuel injection quantity increases as intake air pressure increases, which lead to high heat release rate and high emission level. The optimal intake air temperature varies in different operating area, which can be tuned from ambient temperature to 220℃ by heat management system. The combination of EGR and air boost technology could expand operating area of HCCI engine, which improve indicated mean effective pressure from maximum 510kPa to 720kPa.

  11. THE COMBUSTION CHARACTERISTICS OF LIGNITE BLENDS

    Institute of Scientific and Technical Information of China (English)

    Cheng Jun; Zhou Junhu; Cao Xinyu; Cen Kefa

    2000-01-01

    The combustion characteristics of lignite blends were studied with a thermogravimetric analyzer (t.g.a.), at constant heating rate.The characteristic temperatures were determined from the burning profiles.It was found that the characteristic times of combustion reaction moved forward, the ignition temperature dropped and the burnout efficiency slightly changed when blending lignites.The characteristic parameters of blends could not be predicted as a linear function of the average values of the individual lignites.when blending with less reactive coal, the ignition and burnout characteristics of lignite turned worse.

  12. High Efficiency, Low Emissions Homogeneous Charge Compression Ignition (HCCI) Engines

    Energy Technology Data Exchange (ETDEWEB)

    Gravel, Roland [U.S. Department of Energy' s Vehicle Technologies Office, Washington, DC (United States); Maronde, Carl [National Energy Technology Lab. (NETL), Albany, OR (United States); Gehrke, Chris [Caterpillar, Inc., Peoria, IL (United States); Fiveland, Scott [Caterpillar, Inc., Peoria, IL (United States)

    2010-10-30

    This is the final report of the High Efficiency Clean Combustion (HECC) Research Program for the U.S. Department of Energy. Work under this co-funded program began in August 2005 and finished in July 2010. The objective of this program was to develop and demonstrate a low emission, high thermal efficiency engine system that met 2010 EPA heavy-duty on-highway truck emissions requirements (0.2g/bhp-hr NOx, 0.14g/bhp-hr HC and 0.01g/bhp-hr PM) with a thermal efficiency of 46%. To achieve this goal, development of diesel homogenous charge compression ignition (HCCI) combustion was the chosen approach. This report summarizes the development of diesel HCCI combustion and associated enabling technologies that occurred during the HECC program between August 2005 and July 2010. This program showed that although diesel HCCI with conventional US diesel fuel was not a feasible means to achieve the program objectives, the HCCI load range could be increased with a higher volatility, lower cetane number fuel, such as gasoline, if the combustion rate could be moderated to avoid excessive cylinder pressure rise rates. Given the potential efficiency and emissions benefits, continued research of combustion with low cetane number fuels and the effects of fuel distillation are recommended. The operation of diesel HCCI was only feasible at part-load due to a limited fuel injection window. A 4% fuel consumption benefit versus conventional, low-temperature combustion was realized over the achievable operating range. Several enabling technologies were developed under this program that also benefited non-HCCI combustion. The development of a 300MPa fuel injector enabled the development of extended lifted flame combustion. A design methodology for minimizing the heat transfer to jacket water, known as precision cooling, will benefit conventional combustion engines, as well as HCCI engines. An advanced combustion control system based on cylinder pressure measurements was developed. A Well

  13. Quasi-Dimensional Modelling and Parametric Studies of a Heavy-Duty HCCI Engine

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Pandey

    2011-01-01

    Full Text Available A quasi-dimensional modelling study is conducted for the first time for a heavy duty, diesel-fuelled, multicylinder engine operating in HCCI mode. This quasidimensional approach involves a zero-dimensional single-zone homogeneous charge compression ignition (HCCI combustion model along with a one-dimensional treatment of the intake and exhaust systems. A skeletal chemical kinetic scheme for n-heptane was used in the simulations. Exhaust gas recirculation (EGR and compression ratio (CR were the two parameters that were altered in order to deal with the challenges of combustion phasing control and operating load range extension. Results from the HCCI mode simulations show good potential when compared to conventional diesel performance with respect to important performance parameters such as peak firing pressure, specific fuel consumption, peak pressure rise, and combustion noise. This study shows that HCCI combustion mode can be employed at part load of 25% varying the EGR rates between 0 and 60%.

  14. Miniature free-piston homogeneous charge compression ignition engine-compressor concept - Part II: modeling HCCI combustion in small scales with detailed homogeneous gas phase chemical kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Aichlmayr, H.T.; Kittelson, D.B.; Zachariah, M.R. [The University of Minnesota, Minneapolis (United States). Departments of Mechanical Engineering and Chemistry

    2002-10-01

    Operational maps for crankshaft-equipped miniature homogeneous charge compression ignition engines are established using performance estimation, detailed chemical kinetics, and diffusion models for heat transfer and radical loss. In this study, radical loss was found to be insignificant. In contrast, heat transfer was found to be increasingly significant for 10, 1, and 0.1 W engines, respectively. Also, temperature-pressure trajectories and ignition delay time maps are used to explore relationships between engine operational parameters and HCCI. Lastly, effects of engine operating conditions and design on the indicated fuel conversion efficiency are investigated. (author)

  15. HCCI gasoline engine by General Motors; Ottomotor mit HCCI-Technik von General Motors

    Energy Technology Data Exchange (ETDEWEB)

    Backhaus, R.

    2008-06-15

    General Motors recently presented the HCCI combustion process with cylinder pressure based engine control. A variable valve drive controls the residual gas fraction, and direct injection levels cylinder differences. A calinder pressure sensor system with robust engine control is necessary according to GM for adjusting the 50 mass fraction burnt for maximum efficiency and to compensate the influence of uncontrollable boundary conditions in real operation. (orig.)

  16. Fuel and Combustion Characteristics of Organic Wastes

    Science.gov (United States)

    Namba, Kunihiko; Ida, Tamio

    From a viewpoint of environmental preservation and resource protection, the recycling of wastes has been promoting. Expectations to new energy resource are growing by decrease of fossil fuel. Biomass is one of new energies for prevent global warning. This study is an attempt to burn biomass lamps made from residues in order to thermally recycle waste products of drink industries. The pyrolytic properties of shochu dregs and used tea leaves were observed by thermo-gravimertic analysis (TG) to obtained fundamental data of drink waste pyrolysis. It observed that shochu dregs pyrolyze under lower temperature than used tea leaves. These wastes were compressed by hot press apparatus in the temperature range from 140 to 180 °C for use as Bio-fuel (BF). The combustion behavior of BF was observed in fall-type electric furnace, where video-recording was carried out at sequential steps, such as ignition, visible envelope flame combustion and char combustion to obtain combustion characteristics such as ignition delay, visible flame combustion time and char combustion time.

  17. Numerical simulation research of HCCI diesel engine combustion process%HCCI柴油机燃烧过程数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    李从心; 张欣; 孟金喆

    2006-01-01

    均质压燃(HCCI: homgeneous charge compression ignition)燃烧方式已成为发动机领域的硬件研究热点.针对CA4D32-09型柴油机,对HCCI燃烧过程进行了计算模拟,并利用统计的方法对影响HCCI燃烧特性的因素进行分析,通过计算得出HCCI发动机燃烧过程的影响因素及发动机主要参数对混合气均质特性的作用.

  18. 柴油机HCCI燃烧的均质混合气制备%Preparation of Homogeneous Gas Mixture for Diesel Engine HCCI Combustion

    Institute of Scientific and Technical Information of China (English)

    李棠; 李理光

    2004-01-01

    介绍了均质充量压缩着火燃烧的概念、优缺点及其良好的发展前途与当前面临的困难.分析了HCCI混合气制备的重要性,总结了柴油机HCCI混合气制备的典型方法和成功经验,并分析了混合气制备对HCCI燃烧排放、着火相位的控制以及功率输出的影响,探讨并展望了HCCI混合气制备的可能发展方向.

  19. 基于可变技术的均质充量压缩着火燃烧控制%Variable Technology in HCCI Combustion Control

    Institute of Scientific and Technical Information of China (English)

    邓俊; 胡宗杰; 于水; 栗工; 李理光

    2004-01-01

    均质充量压缩着火(HCCI)是目前发动机领域的研究热点之一.通过分析可变技术对HCCI着火燃烧相位控制的原理及其国内外的研究进展,为实现HCCI成功应用及扩大HCCI功率及转速范围探寻切实可行的方案.分析表明,综合利用可变技术是在更大范围内实现HCCI稳定燃烧、扩大HCCI燃烧功率输出的主要发展方向.

  20. Effects of Injection Timing on Fluid Flow Characteristics of Partially Premixed Combustion Based on High-Speed Particle Image Velocimetry

    KAUST Repository

    Izadi Najafabadi, Mohammad

    2017-03-28

    Partially Premixed Combustion (PPC) is a promising combustion concept ,based on judicious tuning of the charge stratification, to meet the increasing demands of emission legislation and to improve fuel efficiency. Longer ignition delays of PPC in comparison with conventional diesel combustion provide better fuel/air mixture which decreases soot and NO emissions. Moreover, a proper injection timing and strategy for PPC can improve the combustion stability as a result of a higher level of fuel stratification in comparison with the Homogeneous Charge Compression Ignition (HCCI) concept. Injection timing is the major parameter with which to affect the level of fuel and combustion stratification and to control the combustion phasing and the heat release behavior. The scope of the present study is to investigate the fluid flow characteristics of PPC at different injection timings. To this end, high-speed Particle Image Velocimetry (PIV) is implemented in a light-duty optical engine to measure fluid flow characteristics, including the flow fields, mean velocity and cycle-resolved turbulence, inside the piston bowl as well as the squish region with a temporal resolution of 1 crank angle degree at 800 rpm. Two injectors, having 5 and 7 holes, were compared to see their effects on fluid flow and heat release behavior for different injection timings. Reactive and non-reactive measurements were performed to distinguish injection-driven and combustion-driven turbulence. Formation of vortices and higher turbulence levels enhance the air/fuel interaction, changing the level of fuel stratification and combustion duration. Results demonstrate clearly how turbulence level correlates with heat release behavior, and provide a quantitative dataset for validation of numerical simulations.

  1. Knock Sensor Signal and Instant Speed-Based Observer of Gasoline Engine HCCI Combustion Phasing CA10%基于振动信号和瞬时转速信号的HCCI燃烧相位CA10辨识

    Institute of Scientific and Technical Information of China (English)

    张宏超; 谢辉; 陈韬; 赵华

    2011-01-01

    In order to implement close-loop feedback control of HCCI gasoline engine, an observer model of CA10 is presented based on knock sensor signals and instant engine speed by the mathematical method of Artificial Neural Networks. Based on a great deal of experiment on HCCI engine bench equipped with a fully variable valve actuating system, analysis of and comparison between knock signal, instant speed and CA10 are made, and characteristic parameters are extracted from knock sensor signal and instant speed. Then, an observer of CA10 is built with the characteristic signals of knock sensor and instant speed, which is simple in computation and easy to be implemented on microcontroller. It is shown that the observer is capable of calculating CA10 and the detecting average deviation of combustion phase CA10 is less than 1.7 ° CA.%为了实现基于循环的HCCI燃烧闭环控制,提出了一种基于爆震传感器信号和瞬时转速信号的CA10(缸内燃料燃烧10%累积放热量时的曲轴转角θ10)辨识模型.在装有全可变气门系统的汽油HCCI发动机上,测取HCCI发动机各工况下爆震传感器信号和瞬时转速信号,用时频分析方法从爆震传感器信号及瞬时转速中提取表征振动信号相位信息的特征量和瞬时转速信号特缸最,分析了它们和HCCI燃烧相位θ10之间关系,提出了一种计算简单,以爆震传感器和瞬时转速信号特征量为因变量的CA10辨识模型.分析表明,CA10辨识模型能比较准确地识别HCCI燃烧相位的θ10值,对于HCCI动态过程燃烧相位θ10的预测平均误差小于1.7℃ CA.

  2. Negative Valve Overlap Mode of HCCI Operation Using Gasoline and Diesel Blended Fuels

    Institute of Scientific and Technical Information of China (English)

    ZHONG Shaohua; CHEN Yongdong; Miroslaw Lech Wyszynski; XU Hongming

    2007-01-01

    The negative valve overlap (NVO) strategy of HCCI operation was experimentally investigated on a gasoline HCCI engine operated with variable valve timing in association with the addition of diesel fuel. The experimental results show that, by using gasoline and diesel blended fuels, the required NVO interval for suitable HCCI combustion under a given engine speed and a moderate compression ratio condition could be reduced, and the HCCI combustion region was extended remarkably without substantial increase in NO, , emissions under a given inlet and exhaust valve timing due to the improvement of charge ignitability. In addition, the possible scale of NVO was extended. A substantial increase in the lean limit of excess air ratio and the upper limit of load range can be achieved because of higher volumetric efficiency, resulting from the decrease in the required NVO and the presence of less residual gases in cylinder.

  3. Effects of intake air temperature on homogenous charge compression ignition combustion and emissions with gasoline and n-heptane

    Directory of Open Access Journals (Sweden)

    Zhang Jianyong

    2015-01-01

    Full Text Available In a port fuel injection engine, Optimized kinetic process (OKP technology is implemented to realize HCCI combustion with dual-fuel injection. The effects of intake air temperature on HCCI combustion and emissions are investigated. The results show that dual-fuel control prolongs HCCI combustion duration and improves combustion stability. Dual-fuel HCCI combustion needs lower intake air temperature than gasoline HCCI combustion, which reduces the requirements on heat management system. As intake air temperature decreases, air charge increases and maximum pressure rising rate decreases. When intake air temperature is about 55ºC, HCCI combustion becomes worse and misfire happens. In fixed dual fuel content condition, HC and CO emission decreases as intake air temperature increases. The combination of dual-fuel injection and intake air temperature control can expand operation range of HCCI combustion.

  4. Influence of methanol on gasoline fuel HCCI combustion and emission mechanism%甲醇对汽油燃料均质压燃燃烧和排放机理的影响

    Institute of Scientific and Technical Information of China (English)

    吴威龙; 郑朝蕾; 胡林海

    2012-01-01

    为了探讨甲醇对汽油均质压燃( HCCI)燃烧和排放机理的影响,利用CHEMKIN软件从理论上研究了甲醇对汽油HCCI燃烧反应动力学机理的影响.结果表明:甲醇抑制了汽油(甲苯参比燃料)各组分的二次加氧过程,异辛烷基和正庚烷基继续脱氢,再氧化分解产生甲醛;甲苯基则直接氧化分解产生甲醛.随着甲醇体积分数增大,放热开始时刻提前,高温反应阶段的放热率峰值呈先增大后减小趋势.因此,可以通过调整反应中燃料的比例来控制着火时刻和放热峰值.CO和HC摩尔分数随甲醇比例增大逐步减小.随着燃空当量比升高,主燃烧峰值升高,主燃烧持续期延长,OH基生成速率和摩尔分数峰值增大,但放热开始时刻和OH开始生成时刻几乎不变.所以改变当量比可以改变燃烧反应中自由基摩尔分数和反应持续时间,但不能控制着火时刻.CO和HC摩尔分数峰值随当量比增大逐步增大,当量比过小时,大量CO和HC未被氧化.%The influence of methanol on the gasoline fuel HCCI ( homogeneous charge compression ignition) combustion and emission mechanism was investigated by CHEMKIN software. The results show that methanol inhibits the second oxygenation process for the components of gasoline. Isooctyl-alkyl and heptanes-alkyl keep on dehydrogenation, which are then oxidized to become formaldehyde. Tolyl is directly oxidized to be formaldehyde. As the proportion of methanol molar fraction increases, the start time of heat release is advanced, and the peak of heat release rate is increased firstly and then decreased in the high temperature phase. Thus, the ignition time and the peak of heat release can be controlled by adjusting the fuel ratio. CO and HC molar fraction decrease gradually with the increasing of methanol concentration. With the increasing of fuel air equivalence ratio, the main combustion peak increases, the main combustion duration extends, and the production rate

  5. Burning characteristics of microcellular combustible objects

    Directory of Open Access Journals (Sweden)

    Wei-tao Yang

    2014-06-01

    Full Text Available Microcellular combustible objects for application of combustible case, caseless ammunition or combustible detonator-holding tubes are fabricated through one-step foaming process, in which supercritical CO2 is used as foaming agent. The formulations consist of inert polymer binder and ultra fine RDX. For the inner porous structures of microcellular combustible objects, the cell sizes present a unimodal or bimodal distribution by adjusting the foaming conditions. Closed bomb test is to investigate the influence of both porous structure style and RDX content on burning behavior. The sample with bimodal distribution of cell sizes burns faster than that with unimodal distribution, and the concentration of RDX can influence the burning characteristics in a positive manner. In addition, the translation of laminar burning to convective burning is determined by burning rate versus pressure curves of samples at two different loading densities, and the resulting transition pressure is 30 MPa. Moreover, the samples with bigger sample size present higher burning rate, resulting in providing deeper convective depth. Dynamic vivacity of samples is also studied. The results show that the vivacity increases with RDX content and varies with inner structure.

  6. 柴油机HCCI燃烧特点及影响因素分析%Characters of Diesel Engine HCCI Combustion and Analysis on Influencing Factors

    Institute of Scientific and Technical Information of China (English)

    杜宝杰; 李岳林; 王立标; 汤彬

    2008-01-01

    均质充量压缩燃烧HCCI(Homogenous charge Compression Ignition)是一种新型发动机燃烧方式,它能有效地解决传统柴油机燃油经济性差和尾气排放高的问题,特别是能够降低Nox和PM的排放,并进一步提高热效率.柴油机的HCCI燃烧存在HC和CO排放偏高的问题,有待进一步降低,并且由于HCCI燃烧存在的燃烧控制以及适用工况范围窄等问题,因而目前柴油HCCI发动机还未能实现大规模商品化.介绍柴油机HCCI燃烧的特点以及影响柴油机HCCI燃烧的一些重要因素,如EGR、进气温度、压缩比ε、喷油时刻、燃空当量比和喷油压力等对柴油机HCCI燃烧和排放的影响.

  7. Study on combustion characteristics of blended coals

    Energy Technology Data Exchange (ETDEWEB)

    Li Yonghua; Wang Chunbo; Chen Hongwei [North China Electric Power University, Baoding (China)

    2007-02-15

    Power plants in China have to burn blended coal instead of one specific coal for a variety of reasons. So it is of great necessity to investigate the combustion of blended coals. Using a test rig with a capacity of 640 MJ/h with an absolute milling system and flue gas online analysis system, characteristics such as burnout, slag, and pollution of some blended coals were investigated. The ratio of coke and slag as a method of distinguishing coal slagging characteristic was introduced. The results show that the blending of coal has some effect on NOx but there is no obvious rule. SOx emission can be reduced by blending low sulfur coal.

  8. Method and device for diagnosing and controlling combustion instabilities in internal combustion engines operating in or transitioning to homogeneous charge combustion ignition mode

    Science.gov (United States)

    Wagner, Robert M [Knoxville, TN; Daw, Charles S [Knoxville, TN; Green, Johney B [Knoxville, TN; Edwards, Kevin D [Knoxville, TN

    2008-10-07

    This invention is a method of achieving stable, optimal mixtures of HCCI and SI in practical gasoline internal combustion engines comprising the steps of: characterizing the combustion process based on combustion process measurements, determining the ratio of conventional and HCCI combustion, determining the trajectory (sequence) of states for consecutive combustion processes, and determining subsequent combustion process modifications using said information to steer the engine combustion toward desired behavior.

  9. Expanding Robust HCCI Operation with Advanced Valve and Fuel Control Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Szybist, J. P. [Oak Ridge National Lab., Oak Ridge, TN (United States); Confer, K. [Delphi Automotive Systems (United States)

    2012-09-11

    Delphi Automotive Systems and ORNL established this CRADA to advance the commercialization potential of the homogeneous charge compression ignition (HCCI) advanced combustion strategy for gasoline engine platforms. HCCI combustion has been shown by others to produce high diesel-like efficiency on a gasoline engine platform while simultaneously producing low NOX and particulate matter emissions. However, the commercialization barriers that face HCCI combustion are significant, with requirements for a more active engine control system, likely with next-cycle closed-loop feedback control, and with advanced valve train technologies to enable negative valve overlap conditions. In the partnership between Delphi and ORNL, each organization brought a unique and complementary set of skills to the project. Delphi has made a number of breakthroughs with production-intent valve train technologies and controls in recent years to make a part time production-intent HCCI engine plausible. ORNL has extensive knowledge and expertise with HCCI combustion, and also has a versatile research engine with hydraulic valve actuation (HVA) that is useful for guiding production of a cam-based HCCI system. Partnering these knowledge bases and capabilities was essential towards making progress to better understand HCCI combustion and the commercialization barriers that it faces. ORNL and Delphi maintained strong collaboration throughout the project. Meetings were held regularly, with additional reports, presentations, and meetings as necessary to maintain progress. Delphi provided guidance to ORNL regarding operational strategies to investigate on their single-cylinder research engine with HVA and data from their experimental multi-cylinder engine for modeling. ORNL provided single-cylinder engine data and modeling results.

  10. Investigating co-combustion characteristics of bamboo and wood.

    Science.gov (United States)

    Liang, Fang; Wang, Ruijuan; Jiang, Changle; Yang, Xiaomeng; Zhang, Tao; Hu, Wanhe; Mi, Bingbing; Liu, Zhijia

    2017-07-04

    To investigate co-combustion characteristics of bamboo and wood, moso bamboo and masson pine were torrefied and mixed with different blend ratios. The combustion process was examined by thermogravimetric analyzer (TGA). The results showed the combustion process of samples included volatile emission and oxidation combustion as well as char combustion. The main mass loss of biomass blends occurred at volatile emission and oxidation combustion stage, while that of torrefied biomass occurred at char combustion stage. With the increase of bamboo content, characteristic temperatures decreased. Compared with untreated biomass, torrefied biomass had a higher initial and burnout temperature. With the increase of heating rates, combustion process of samples shifted to higher temperatures. Compared with non-isothermal models, activation energy obtained from isothermal model was lower. The result is helpful to promote development of co-combustion of bamboo and masson pine wastes. Copyright © 2017. Published by Elsevier Ltd.

  11. Identification of the dynamic operating envelope of HCCI engines using class imbalance learning.

    Science.gov (United States)

    Janakiraman, Vijay Manikandan; Nguyen, XuanLong; Sterniak, Jeff; Assanis, Dennis

    2015-01-01

    Homogeneous charge compression ignition (HCCI) is a futuristic automotive engine technology that can significantly improve fuel economy and reduce emissions. HCCI engine operation is constrained by combustion instabilities, such as knock, ringing, misfires, high-variability combustion, and so on, and it becomes important to identify the operating envelope defined by these constraints for use in engine diagnostics and controller design. HCCI combustion is dominated by complex nonlinear dynamics, and a first-principle-based dynamic modeling of the operating envelope becomes intractable. In this paper, a machine learning approach is presented to identify the stable operating envelope of HCCI combustion, by learning directly from the experimental data. Stability is defined using thresholds on combustion features obtained from engine in-cylinder pressure measurements. This paper considers instabilities arising from engine misfire and high-variability combustion. A gasoline HCCI engine is used for generating stable and unstable data observations. Owing to an imbalance in class proportions in the data set, the models are developed both based on resampling the data set (by undersampling and oversampling) and based on a cost-sensitive learning method (by overweighting the minority class relative to the majority class observations). Support vector machines (SVMs) and recently developed extreme learning machines (ELM) are utilized for developing dynamic classifiers. The results compared against linear classification methods show that cost-sensitive nonlinear ELM and SVM classification algorithms are well suited for the problem. However, the SVM envelope model requires about 80% more parameters for an accuracy improvement of 3% compared with the ELM envelope model indicating that ELM models may be computationally suitable for the engine application. The proposed modeling approach shows that HCCI engine misfires and high-variability combustion can be predicted ahead of time

  12. Combustion Characteristics of Polyethylene and Coal Powder at High Temperature

    Institute of Scientific and Technical Information of China (English)

    LONG Shi-gang; CAO Feng; WANG Si-wei; SUN Liu-heng; PANG Jian-ming; SUN Yu-ping

    2008-01-01

    To study the combustion characteristics of the polyethylene (PE) particle and coal powder at blast temperature of the blast furnace, the contents of CO and CO2 of off-gas during the combustion of PE particle and coal powder at the 1 200 ℃ and 1 250 ℃ were measured using carbon monoxide and carbon dioxide infrared analyzer, and then the corresponding combustion ratio was calculated. The results showed that when the temperature is high, the combustion speed of PE and coal powder is high and the corresponding combustion ratio is high. Whereas, the combustion speed and ratio of PE are much higher than those of coal powder.

  13. Combustion

    CERN Document Server

    Glassman, Irvin

    1987-01-01

    Combustion, Second Edition focuses on the underlying principles of combustion and covers topics ranging from chemical thermodynamics and flame temperatures to chemical kinetics, detonation, ignition, and oxidation characteristics of fuels. Diffusion flames, flame phenomena in premixed combustible gases, and combustion of nonvolatile fuels are also discussed. This book consists of nine chapters and begins by introducing the reader to heats of reaction and formation, free energy and the equilibrium constants, and flame temperature calculations. The next chapter explores the rates of reactio

  14. Study on combustion characteristics of blended coals

    Institute of Scientific and Technical Information of China (English)

    LI Yonghua; WANG Chunbo; CHEN Hongwei

    2007-01-01

    Power plants in China have to burn blended coal instead of one specific coal for a variety of reasons.So it is of great necessity to investigate the combustion of blended coals.Using a test rig with a capacity of 640 MJ/h with an absolute milling system and flue gas online analysis system,characteristics such as burnout,slag,and pollution of some blended coals were investigated.The ratio of coke and slag as a method of distinguishing coal slagging characteristic was introduced.The results show that the blending of coal has some effect on NOx but there is no obvious rule.SOx emission can be reduced by blending low sulfur coal.

  15. Experimental Investigation of the Effect of Mixed Additives on Homogeneous Charge Compression Ignition Combustion

    Institute of Scientific and Technical Information of China (English)

    LI Chao; JI Chang-wei; HE Chao; LI Yun-zhe; HE Hong; SHEN Zi-you

    2008-01-01

    The experimental investigation of homogeneous charge compression ignition (HCCI) process is carried out on a 4-cylinder diesel engine. One of the cylinders is modified for HCCI combustion with mixed additives. The influence of mixed additives on the HCCI combustion process is investigated. The experimental results indicate that the mixed additives are better than the single additives for HCCI fuel, causing ignition and heat release to be advanced and the peak of heat release rate to increase under the condition of different engine speeds and steady HCCI combustion. Moreover, with the increase in engine speed, the influence of mixed additives on HCCI combustion is more obvious. In addition, the mixed additives are beneficial to improve HCCI engine misfire at a high engine speed and make the engine operate stable.

  16. Experimental investigation of homogeneous charge compression ignition combustion of biodiesel fuel with external mixture formation in a CI engine.

    Science.gov (United States)

    Ganesh, D; Nagarajan, G; Ganesan, S

    2014-01-01

    In parallel to the interest in renewable fuels, there has also been increased interest in homogeneous charge compression ignition (HCCI) combustion. HCCI engines are being actively developed because they have the potential to be highly efficient and to produce low emissions. Even though HCCI has been researched extensively, few challenges still exist. These include controlling the combustion at higher loads and the formation of a homogeneous mixture. To obtain better homogeneity, in the present investigation external mixture formation method was adopted, in which the fuel vaporiser was used to achieve excellent HCCI combustion in a single cylinder air-cooled direct injection diesel engine. In continuation of our previous works, in the current study a vaporised jatropha methyl ester (JME) was mixed with air to form a homogeneous mixture and inducted into the cylinder during the intake stroke to analyze the combustion, emission and performance characteristics. To control the early ignition of JME vapor-air mixture, cooled (30 °C) Exhaust gas recirculation (EGR) technique was adopted. The experimental result shows 81% reduction in NOx and 72% reduction in smoke emission.

  17. Characteristics of oily sludge combustion in circulating fluidized beds.

    Science.gov (United States)

    Zhou, Lingsheng; Jiang, Xiumin; Liu, Jianguo

    2009-10-15

    Incineration of oily sludge in circulating fluidized beds may be an effective way for its management in some cases. The objective of the present paper is to investigate combustion characteristics of oily sludge, which would be helpful and useful for the design and simulation of a circulating fluidized bed. Firstly, the pyrolysis and combustion of oily sludge were studied through some thermal analyses, which included the thermogravimetric (TG) analysis and the differential thermal analytical (DTA) analysis. It was found that the combustion of oily sludge might be the combustion of its pyrolysis products. Secondly, an experiment for measuring of main components of the volatile from oily sludge pyrolysis was carried out. Some mathematic correlations about the compositions of volatile from oily sludge devolatilization were achieved from the experimental results. Finally, the combustion characteristics of oily sludge was studied in a lab-scale circulating fluidized bed, which could obtain some information about the location of release and combustion of the volatiles.

  18. Nonlinear Dynamic Characteristics of Combustion Wave in SHS Process

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The characteristic of combustion wave and its change were analyzed by numerical value calculation and computer simulation,based on the combustion dynamical model of SHS process. It is shown that with the change of condition parameters in SHS process various time-space order combustion waves appear.It is concluded from non-liner dynamical mechanism analysis that the strong coupling of two non-linear dynamical processes is the dynamical mechanism causing the time-space order dissipation structures.

  19. Some characteristics of fine beryllium particle combustion

    Science.gov (United States)

    Davydov, D. A.; Kholopova, O. V.; Kolbasov, B. N.

    2007-08-01

    Beryllium dust will be produced under plasma interaction with beryllium armor of the first wall in ITER. Exothermal reaction of this dust with water steam or air, which can leak into the reactor vacuum chamber in some accidents, gives concern in respect to reactor safety. Results of studies devoted to combustion of fine beryllium particles are reviewed in the paper. A chemically active medium and elevated temperature are prerequisite to the combustion of beryllium particles. Their ignition is hampered by oxide films, which form a diffusion barrier on the particle surface as a result of pre-flame oxidation. The temperature to initiate combustion of particles depends on flame temperature, particle size, composition of combustible mixture, heating rate and other factors. In mixtures enriched with combustible, the flame temperature necessary to ignite individual particles approaches the beryllium boiling temperature.

  20. A numerical study of turbulent combustion characteristics in a combustion chamber of a scramjet engine

    Institute of Scientific and Technical Information of China (English)

    LEE; ChunHian

    2010-01-01

    3D numerical simulation of flow fields in a combustion chamber of a scramjet engine using an SST turbulence model with an explicit compressibility correction was performed and the results were compared to the experimental results.The characteristics of the turbulent combustion flow fields were analyzed via the numerical results and presented.In order to identify the mechanisms of turbulent combustion in supersonic flows,the evolutions of governing dimensionless parameters in the flow fields were investigated based on the theory of combustion and the available numerical results.It was found that the supersonic combustion takes place in the region of fully developed turbulence and that the strongest effects of turbulence and combustion processes appear in the vicinity of the injector.The unsteady effects and the local flame extinction phenomenon induced by turbulent flows were found to be negligibly small,and the steady flamelet approximation will hold for practical applications.

  1. Effect of oxydesulphurization on the combustion characteristics of coal

    Energy Technology Data Exchange (ETDEWEB)

    Yaman, S.; Kucukbayrak, S. [Technical University of Istanbul, Istanbul (Turkey). Dept. of Chemical Engineering

    1997-06-01

    Desulphurization of a Turkish lignite by oxydesulphurization using dilute alkaline solutions, obtained by the extraction of fly ash with water, was carried out under 0-1.5 MPa partial pressure of oxygen at temperatures between 403 and 498 K for 30-90 min time intervals. The combustion characteristics of original and desulphurized lignite samples are compared using TGA. DTG curves were derived and the effects of desulphurization conditions such as temperature, partial pressure of oxygen and time on coal reactivity were studied. Ignition temperature, maximum combustion rate, combustion period, and the end temperature of combustion were considered. Relations between coal reactivity and removals of sulphur and ash contents were also studied.

  2. Experimental Investigation on Extending Load Range of Diesel HCCI Engine by Internal EGR and Boost%内部EGR及增压拓展柴油HCCI燃烧负荷范围试验研究

    Institute of Scientific and Technical Information of China (English)

    桂勇; 孙佑成; 徐敏; 邓康耀; 石磊

    2012-01-01

    在135单缸柴油机上对比了传统燃烧模式和HCCI燃烧模式的负荷特性,优化了HCCI燃烧模式的喷油始点,分析了内部EGR率及增压压力对HCCI燃烧负荷范围及排放的影响.试验结果表明:对于负气门重叠期喷油的HCCI燃烧模式,1 500 r/min下,最佳喷油始点为370°BTDC,气门重叠期为-30°时既保证了较低的NOx排放,又可以获得较佳的负荷范围;提高增压压力不仅可以拓展HCCI燃烧的负荷上限,对负荷下限的燃烧稳定性也有利;将增压压力提高到0.18 MPa时,负荷上限从传统燃烧的0.594 MPa上升到0.723 MPa,但负荷下限较传统燃烧模式要高,CO排放、烟度和燃油经济性都较差.%On a single cylinder diesel engine, the load characteristics between traditional combustion and HCCI combustion were compared, the injection timing of HCCI was optimized and the influences of internal EGR rate and boost pressure on HCCI combustion load range and emissions were analyzed. The results show that the best injection timing of HCCI mode with the negative valve overlap at 1500 r/min is 370°BTDC. The - 30° valve overlap can guarantee lower NOx emission and better load range. The increase of boost pressure extends the upper load limit of HCCI combustion and is beneficial to the combustion stability of lower load limit. Improving the boost pressure on 0.18 MPa, the upper load limit increases from 0. 594 MPa to 0. 723 MPa, but lower load limit also increases, which gives worse CO emission, smoke and fuel economy.

  3. Combustion characteristics and kinetics of bio-oil

    Institute of Scientific and Technical Information of China (English)

    Ruixia ZHANG; Zhaoping ZHONG; Yaji HUANG

    2009-01-01

    The combustion characteristics of bio-oils derived from rice husk and corn were studied by thermogravimetry analysis. According to the thermo-gravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA) curves of bio-oils in air and nitrogen atmosphere, we analyzed the combustion characteristics of different kinds of bio-oils in different atmospheres and worked out the combustion kinetics parameters of the bio-oil, providing reliable base data for the burning of bio-oil. The thermogravimetry indicated that the combustion process of bio-oil was divided into three stages. At the same time, the combustion process can be described by different order reaction models, and with the method of Coats-Redfern, the activation energy and frequency factor of different kinds of bio-oils were obtained.

  4. MODELING OF FUEL SPRAY CHARACTERISTICS AND DIESEL COMBUSTION CHAMBER PARAMETERS

    Directory of Open Access Journals (Sweden)

    G. M. Kukharonak

    2011-01-01

    Full Text Available The computer model for coordination of fuel spray characteristics with diesel combustion chamber parameters has been created in the paper.  The model allows to observe fuel sprays  develоpment in diesel cylinder at any moment of injection, to calculate characteristics of fuel sprays with due account of a shape and dimensions of a combustion chamber, timely to change fuel injection characteristics and supercharging parameters, shape and dimensions of a combustion chamber. Moreover the computer model permits to determine parameters of holes in an injector nozzle that provides the required fuel sprays characteristics at the stage of designing a diesel engine. Combustion chamber parameters for 4ЧН11/12.5 diesel engine have been determined in the paper.

  5. Experimental Study on OKP HCCI Gasoline Engine%优化动力HCCI汽油机的试验研究

    Institute of Scientific and Technical Information of China (English)

    缪金荣; 张旭洲; 沈义涛; 陈林; 方俊华; 吕兴才; 黄震

    2011-01-01

    With the OKP technology, the HCCI combustion of 4-cylinder gasoline engine was realized through intake heating.The performance of combustion, HC emission and fuel consumption for OKP HCCI gasoline engine was researched, the influences of compression ratio and excess air ratio on HCCI combustion were analyzed and the HC emission rule during the SI-HCCI switching was researched by the experiment. The results indicate that OKP HCCI gasoline engine can realize the SI-HCCI switch in 15 cycles. Through the HCCI combustion, the fuel consumption rate decreases dramatically and the HC emission level is equivalent to or even lower than that of SI mode.%采用优化动力(OKP)技术手段,利用进气加热实现了产品4缸汽油机的HCCI燃烧.研究了OKP HCCI汽油机的燃烧、HC排放及燃油消耗等特性,分析了压缩比及过量空气系数对HCCI燃烧的影响,并对SI-HCCI切换过程中HC排放规律进行了试验研究.结果表明,OKP HCCI汽油机能在15个循环内实现SI-HCCI燃烧模式的切换,HCCI燃烧能大幅地降低燃油消耗并且能达到与SI模式相当甚至更低水平的HC排放.

  6. Numerical Analysis on Combustion Characteristic of Leaf Spring Rotary Engine

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2015-08-01

    Full Text Available The purpose of this paper is to investigate combustion characteristics for rotary engine via numerical studies. A 3D numerical model was developed to study the influence of several operative parameters on combustion characteristics. A novel rotary engine called, “Leaf Spring Rotary Engine”, was used to illustrate the structure and principle of the engine. The aims are to (1 improve the understanding of combustion process, and (2 quantify the influence of rotational speed, excess air ratio, initial pressure and temperature on combustion characteristics. The chamber space changed with crankshaft rotation. Due to the complexity of chamber volume, an equivalent modeling method was presented to simulate the chamber space variation. The numerical simulations were performed by solving the incompressible, multiphase Unsteady Reynolds-Averaged Navier–Stokes Equations via the commercial code FLUENT using a transport equation-based combustion model; a realizable  turbulence model and finite-rate/eddy-dissipation model were used to account for the effect of local factors on the combustion characteristics.

  7. A Comprehensive Numerical Study on Effects of Natural Gas Composition on the Operation of an HCCI Engine Une étude numérique complète sur les effets de la composition du gaz naturel carburant sur le réglage d’un moteur HCCI

    Directory of Open Access Journals (Sweden)

    Jahanian O.

    2011-11-01

    Full Text Available Homogeneous Charge Compression Ignition (HCCI engine is a promising idea to reduce fuel consumption and engine emissions. Natural Gas (NG, usually referred as clean fuel, is an appropriate choice for HCCI engines due to its suitable capability of making homogenous mixture with air. However, varying composition of Natural Gas strongly affects the auto-ignition characteristics of in-cylinder mixture and the performance of the HCCI engine. This paper has focused on the influence of Natural Gas composition on engine operation in HCCI mode. Six different compositions of Natural Gas (including pure methane have been considered to study the engine performance via a thermo-kinetic zero-dimensional model. The simulation code covers the detailed chemical kinetics of Natural Gas combustion, which includes Zeldovich extended mechanism to evaluate NOx emission. Validations have been made using experimental data from other works to ensure the accuracy needed for comparison study. The equivalence ratio and the compression ratio are held constant but the engine speed and mixture initial temperature are changed for comparison study. Results show that the peak value of pressure/temperature of in-cylinder mixture is dependent of fuel Wobbe number. Furthermore, engine gross indicated power is linearly related to fuel Wobbe number. Gross indicated work, gross mean effective pressure, and NOx are the other parameters utilized to compare the performance of engine using different fuel compositions. Le moteur HCCI (Homogeneous Charge Compression Ignition, ou à allumage par compression d’une charge homogène est une idée prometteuse pour réduire la consommation de carburant et les émissions polluantes. Le gaz naturel, considéré généralement comme un carburant propre, est un choix approprié pour les moteurs HCCI en raison de sa capacité à former avec l’air un mélange homogène. Cependant, la composition du gaz naturel influe fortement sur les caract

  8. Experimental Investigation of Piston Heat Transfer in a Light Duty Engine Under Conventional Diesel, Homogeneous Charge Compression Ignition, and Reactivity Controlled Compression Ignition Combustion Regimes

    Science.gov (United States)

    2014-01-15

    engine speed and load conditions. The closed-cycle integrated and peak heat transfer rates were found to be lower for HCCI and RCCI when compared to...limit the load of HCCI due to practical engine limitations. Additionally, HCCI lacks a fast-response combustion phasing control, such as spark...cylinder research engine under Conventional Diesel (CDC), Homogeneous Charge Compression Ignition ( HCCI ), and Reactivity Controlled Compression Ignition

  9. DETAILED CHEMICAL KINETIC MODELING OF ISO-OCTANE SI-HCCI TRANSITION

    Energy Technology Data Exchange (ETDEWEB)

    Havstad, M A; Aceves, S M; McNenly, M J; Piggott, W T; Edwards, K D; Wagner, R M; Daw, C S; Finney, C A

    2009-10-12

    The authors describe a CHEMKIN-based multi-zone model that simulates the expected combustion variations in a single-cylinder engine fueled with iso-octane as the engine transitions from spark-ignited (ST) combustion to homogeneous charge compression ignition (HCCI) combustion. The model includes a 63-species reaction mechanism and mass and energy balances for the cylinder and the exhaust flow. For this study they assumed that the SI-to-HCCI transition is implemented by means of increasing the internal exhaust gas recirculation (EGR) at constant engine speed. This transition scneario is consistent with that implemented in previously reported experimental measurements on an experimental engine equipped with variable valve actuation. They find that the model captures many of the important experimental trends, including stable SI combustion at low EGR ({approx} 0.10), a transition to highly unstable combustion at intermediate EGR, and finally stable HCCI combustion at very high EGR ({approx} 0.75). Remaining differences between the predicted and experimental instability patterns indicate that there is further room for model improvement.

  10. Harmonic components of cylinder pressure variation and their characteristics for combustion noise in internal combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.R.; Miyamoto, Noboru; Murayama, Tadashi

    1987-10-31

    Combustion noise is a serious problem in internal combustion engines, especially diesel engines. Although the cylinder pressure variation is easily visible tool to evaluate the combustion noise and thermal efficiency, the exciting force in engine combustion noise has not been completely determined. Cylinder pressure variation for different combustion behaviors and their harmonic components were calculated and an attempt was made to correlate the various components. It was found that the logarithmic harmonic components of cylinder pressure variations, the cylinder pressure level (CPL) can be described by a function with four variables, the values of cylinder pressure variation. The results of this paper is summarized as follows: 1) A relationship was established between CPL and four characteristic values describing the cylinder pressure and variation diagram. 2) Harmonic components of cylinder pressure variations are described by a linear function with four variables and four characteristic values. 3) In this case, the coefficients of the four variables depend solely on the order of engine revolutions and are independent of combustion behavior and engine operating conditions. (13 figs, 7 refs)

  11. Model analysis for combustion characteristics of RDF pellet

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Fundamental studies of the combustion characteristics and the de-HCl behavior of a single refuse-derived fuel(RDF) pellet were carried out to explain the de-HCl phenomena of RDF during fluidized bed combustion and to provide data for the development of high efficiency power generation technology using RDF previously. For further interpreting the devolatilization and the char combustion processes of RDF quantitatively, an unsteady combustion model for single RDF pellet, involving reaction rates, heat transfer and oxygen diffusion in the RDF pellet, was developed. Comparisons of simulation results with experimental data for mass loss of the RDF samples made from municipal solid waste, wood chips and poly-propylene when they were heated at 10K/min or put into the furnace under 1073K show the verifiability of the model. Using this model, the distributions of the temperature and the reaction ratio along the radius of RDF pellet during the devolatilization process and the char combustion process were presented, and discussion about the inference of heating rate on the combustion characteristics were performed.

  12. Fuel injection characteristics of diesel-stimulated natural gas combustion

    Energy Technology Data Exchange (ETDEWEB)

    Mbarawa, M.; Milton, B.E.; Casey, R.T.; Miao, H. [University of New South Wales, School of Mechanical and Manufacturing Engineering, Sydney, NSW (Australia)

    1999-07-01

    Although dual-fuel (DF) engines using a low cetane number primary fuel such as natural gas (NG) ignited by a pilot diesel spay have been the subject of much investigation over years, there are still many unknown problems related to the fundamental combustion process of two fuels. In this work, a quiescent constant volume combustion bomb and a 3-D numerical model have been used to study the effects of injection nozzle characteristics on the combustion of pre-mixed NG/air with pilot distillate spray. Experimental tests were conducted on combustion process of pre-mixed natural gas/air with pilot injection pressure of 30 and 20 MPa with a 4 hole injector, and also with injector nozzle of 8 and 4 holes. The global results obtained from computations compared well with the experimental results. (Author)

  13. Application of exhaust gas fuel reforming in diesel and homogeneous charge compression ignition (HCCI) engines fuelled with biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Tsolakis, A. [School of Engineering, Mechanical and Manufacturing Engineering, University of Birmingham, Birmingham B15 2TT (United Kingdom); Megaritis, A. [Department of Mechanical Engineering, School of Engineering and Design, Brunel University, West London, Uxbridge UB8 3PH (United Kingdom); Yap, D. [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore)

    2008-03-15

    This paper documents the application of exhaust gas fuel reforming of two alternative fuels, biodiesel and bioethanol, in internal combustion engines. The exhaust gas fuel reforming process is a method of on-board production of hydrogen-rich gas by catalytic reaction of fuel and engine exhaust gas. The benefits of exhaust gas fuel reforming have been demonstrated by adding simulated reformed gas to a diesel engine fuelled by a mixture of 50% ultra low sulphur diesel (ULSD) and 50% rapeseed methyl ester (RME) as well as to a homogeneous charge compression ignition (HCCI) engine fuelled by bioethanol. In the case of the biodiesel fuelled engine, a reduction of NO{sub x} emissions was achieved without considerable smoke increase. In the case of the bioethanol fuelled HCCI engine, the engine tolerance to exhaust gas recirculation (EGR) was extended and hence the typically high pressure rise rates of HCCI engines, associated with intense combustion noise, were reduced. (author)

  14. Combustion characteristics of thermally stressed hydrocarbon fuels

    Science.gov (United States)

    Curtis, Colin William

    Liquid propelled propulsion systems, which range from rocket systems to hypersonic scramjet and ramjet engines, require active cooling in order to prevent additional payload requirements. In these systems, the liquid fuel is used as a coolant and is delivered through micro-channels that surround the combustion chambers, nozzles, as well as the exterior surfaces in order to extract heat from these affected areas. During this process, heat exchange occurs through phase change, sensible heat extraction, and endothermic reactions experienced by the liquid fuel. Previous research has demonstrated the significant modifications in fuel composition and changes to the fuel's physical properties that can result from these endothermic reactions. As a next step, we are experimentally investigating the effect that endothermic reactions have on fundamental flame behavior for real hydrocarbon fuels that are used as rocket and jet propellants. To achieve this goal, we have developed a counter-flow flame burner to measure extinction limits of the thermally stressed fuels. The counter-flow flame system is to be coupled with a high pressure reactor, capable of subjecting the fuel to 170 atm and 873 K, effectively simulating the extreme environment that cause the liquid fuel to experience endothermic reactions. The fundamental flame properties of the reacted fuels will be compared to those of unreacted fuels, allowing us to determine the role of endothermic reactions on the combustion behavior of current hydrocarbon jet and rocket propellants. To quantify the change in transport properties and chemical kinetics of the reacting mixture, simultaneous numerical simulations of the reactor portion of the experiment coupled with a counterflow flame simulation are performed using n-heptane and n-dodecane.

  15. Homogeneous Charge Compression Ignition Combustion of Dimethyl Ether

    DEFF Research Database (Denmark)

    Pedersen, Troels Dyhr

    This thesis is based on experimental and numerical studies on the use of dimethyl ether (DME) in the homogeneous charge compression ignition (HCCI) combustion process. The first paper in this thesis was published in 2007 and describes HCCI combustion of pure DME in a small diesel engine. The tests...... a substantial combustion delay in HCCI operation with DME to achieve post TDC combustion. By adding methanol to the inlet port during HCCI combustion of DME, the engine reached 50 percent of its full DI CI load capability without engine knock at 1000 rpm and somewhat less at 1800 rpm. The engine also had EGR...... were designed to investigate the effect of engine speed, compression ratio and equivalence ratio on the combustion timing and the engine performance. It was found that the required compression ratio depended on the equivalence ratio used. A lower equivalence ratio requires a higher compression ratio...

  16. Control Strategy Study of Ethanol SI/HCCI Combustion Mode Smooth Transition%乙醇SI/HCCI燃烧模式平稳转换控制策略研究

    Institute of Scientific and Technical Information of China (English)

    黄为钧; 黄焱; 杨晓辉

    2008-01-01

    如何将均质压燃(HCCI)应用到实际发动机上是当前HCCI研究的热点之一,采用HCCI/SI复合燃烧模式是潜力巨大的出路之一.当发动机采用这种复合燃烧模式时,HCCl只能在一定范围内运行的特点决定了发动机在HCCI和SI两种燃烧模式边界工况发生负荷变化时,需要进行两种燃烧模式的相互转换.实现两种燃烧模式的平稳转换需要对转换过程中影响转换平顺性的因素进行分析,综合控制.通过分析试验所得数据,本研究基于主节气门运动规律、点火提前角和供油规律3个主要影响因素提出了主动、协同的控制策略,实现了两种燃烧模式的平稳转换.

  17. Homogeneous Charge Compression Ignition Combustion: Challenges and Proposed Solutions

    Directory of Open Access Journals (Sweden)

    Mohammad Izadi Najafabadi

    2013-01-01

    Full Text Available Engine and car manufacturers are experiencing the demand concerning fuel efficiency and low emissions from both consumers and governments. Homogeneous charge compression ignition (HCCI is an alternative combustion technology that is cleaner and more efficient than the other types of combustion. Although the thermal efficiency and NOx emission of HCCI engine are greater in comparison with traditional engines, HCCI combustion has several main difficulties such as controlling of ignition timing, limited power output, and weak cold-start capability. In this study a literature review on HCCI engine has been performed and HCCI challenges and proposed solutions have been investigated from the point view of Ignition Timing that is the main problem of this engine. HCCI challenges are investigated by many IC engine researchers during the last decade, but practical solutions have not been presented for a fully HCCI engine. Some of the solutions are slow response time and some of them are technically difficult to implement. So it seems that fully HCCI engine needs more investigation to meet its mass-production and the future research and application should be considered as part of an effort to achieve low-temperature combustion in a wide range of operating conditions in an IC engine.

  18. Homogeneous Charge Compression Ignition Combustion of Dimethyl Ether

    OpenAIRE

    Pedersen, Troels Dyhr; Schramm, Jesper

    2011-01-01

    This thesis is based on experimental and numerical studies on the use of dimethyl ether (DME) in the homogeneous charge compression ignition (HCCI) combustion process. The first paper in this thesis was published in 2007 and describes HCCI combustion of pure DME in a small diesel engine. The tests were designed to investigate the effect of engine speed, compression ratio and equivalence ratio on the combustion timing and the engine performance. It was found that the required compression ratio...

  19. [Quantitative spectrum analysis of characteristic gases of spontaneous combustion coal].

    Science.gov (United States)

    Liang, Yun-Tao; Tang, Xiao-Jun; Luo, Hai-Zhu; Sun, Yong

    2011-09-01

    Aimed at the characteristics of spontaneous combustion gas such as a variety of gases, lou limit of detection, and critical requirement of safety, Fourier transform infrared (FTIR) spectral analysis is presented to analyze characteristic gases of spontaneous combustion In this paper, analysis method is introduced at first by combing characteristics of absorption spectra of analyte and analysis requirement. Parameter setting method, sample preparation, feature variable abstract and analysis model building are taken into consideration. The methods of sample preparation, feature abstraction and analysis model are introduced in detail. And then, eleven kinds of gases were tested with Tensor 27 spectrometer. CH4, C2H6, C3H8, iC4H10, nC4H10, C2 H4, C3 H6, C3 H2, SF6, CO and CO2 were included. The optical path length was 10 cm while the spectra resolution was set as 1 cm(-1). The testing results show that the detection limit of all analytes is less than 2 x 10(-6). All the detection limits fit the measurement requirement of spontaneous combustion gas, which means that FTIR may be an ideal instrument and the analysis method used in this paper is competent for spontaneous combustion gas measurement on line.

  20. Experimental study on combustion characteristics of municipal solid waste

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    As incineration provides a relatively safe means of disposal, significant reduction of weight and volume, and energy recovery from thewaste, it was adopted by many countries. For the experimental investigation on the combustion characteristics of municipal solid waste(MSW),a lab scale fluidized bed facility was constructed. Many kinds of combustion runs were conducted in this fluidized bed combustion facility. Theexamined parameters were bed temperature(773 to 1143K), form of fuels ( scrap or whole), moisture of fuels and so on. Concentration of CO2,CO,SO2, O2 and NOx in the flue gas were monitored and recorded every 5 seconds. The temperatures along the reactor are recorded every 10seconds. Experimental results were given and analyzed.

  1. Development of the RIOT web service and information technologies to enable mechanism reduction for HCCI simulations

    Science.gov (United States)

    Schuchardt, Karen; Oluwole, Oluwayemisi; Pitz, William; Rahn, Larry A.; Green, William H., Jr.; Leahy, David; Pancerella, Carmen; Sjöberg, Magnus; Dec, John

    2005-01-01

    New approaches are being explored to facilitate multidisciplinary collaborative research of Homogenous Charge Compression Ignition (HCCI) combustion processes. In this paper, collaborative sharing of the Range Identification and Optimization Toolkit (RIOT) and related data and models is discussed. RIOT is a developmental approach to reduce the computational complexity of detailed chemical kinetic mechanisms, enabling their use in modeling kinetically controlled combustion applications such as HCCI. These approaches are being developed and piloted as a part of the Collaboratory for Multiscale Chemical Sciences (CMCS) project. The capabilities of the RIOT code are shared through a portlet in the CMCS portal that allows easy specification and processing of RIOT inputs, remote execution of RIOT, tracking of data pedigree, and translation of RIOT outputs to a table view and to a commonly-used chemical model format.

  2. Development of the RIOT Web Service and Information Technologies to Enable Mechanism Reduction for HCCI Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Schuchardt, K; Oluwole, O; Pitz, W J; Rahn, L; Green, W H; Leahy, D; Pancerella, C; Sj?berg, M; Dec, J

    2005-06-13

    New approaches are being explored to facilitate multidisciplinary collaborative research of Homogeneous Charge Compression Ignition (HCCI) combustion processes. In this paper, collaborative sharing of the Range Identification and Optimization Toolkit (RIOT) and related data and models is discussed. RIOT is a developmental approach to reduce the computational of detailed chemical kinetic mechanisms, enabling their use in modeling kinetically controlled combustion applications such as HCCI. These approaches are being developed and piloted as a part of the Collaboratory for Multiscale Chemical Sciences (CMCS) project. The capabilities of the RIOT code are shared through a portlet in the CMCS portal that allows easy specification and processing of RIOT inputs, remote execution of RIOT, tracking of data pedigree, and translation of RIOT outputs to a table view and to a commonly-used mechanism format.

  3. Combustion Characteristics of Coated Nano Aluminum in Composite Propellants

    Directory of Open Access Journals (Sweden)

    Yunlan Sun

    2006-10-01

    Full Text Available The effects of coated nano-sized aluminum (Al powder (n-Al and micron-sized Al powder(g-Al in propellants on the burning rate and pressure exponent have been investigated. Theresults show that the burning rates of propellants increase as the n-Al content increases, butthe burning rate pressure exponents tend to decrease. Compared with propellant containing-Al, the increments of burning rates of propellants containing n-Al powder reduce graduallywith increase in the pressure because of the differences of the combustion characteristics andignition performances of n-Al powder and g-Al powder. Single short distance photograph, scanningelectron microscopy, x-ray fluorescence analysis were used to characterise the flame image,combustion phenomena, the quenched surface image, and surface elements. A substantialdifference in combustion characteristics of n-Al powder has been found in comparison with-Al powder. In addition, oxygen-bomb combustion heat, ignition temperature, and recoveryratio of residues were measured.

  4. Fuels and Combustion

    KAUST Repository

    Johansson, Bengt

    2016-08-17

    This chapter discusses the combustion processes and the link to the fuel properties that are suitable for them. It describes the basic three concepts, including spark ignition (SI) and compression ignition (CI), and homogeneous charge compression ignition (HCCI). The fuel used in a CI engine is vastly different from that in an SI engine. In an SI engine, the fuel should sustain high pressure and temperature without autoignition. Apart from the dominating SI and CI engines, it is also possible to operate with a type of combustion: autoignition. With HCCI, the fuel and air are fully premixed before combustion as in the SI engine, but combustion is started by the increased pressure and temperature during the compression stroke. Apart from the three combustion processes, there are also a few combined or intermediate concepts, such as Spark-Assisted Compression Ignition (SACI). Those concepts are discussed in terms of the requirements of fuel properties.

  5. Combustion and Performance Characteristics of CI Engine Running with Biodiesel

    OpenAIRE

    Tesfa, Belachew; Mishra, Rakesh; Gu, Fengshou; Ball, Andrew

    2013-01-01

    Biodiesel is one of the alternative fuels which is renewable and environmentally friendly and can be used in diesel engines with little or no modifications. In the present study, experimental investigations were carried out on the effects of biodiesel types, biodiesel fraction and physical properties on the combustion and performance characteristics of a compression ignition (CI) engine. The experimental work was conducted on a four-cylinder, four -stroke, direct injection (DI) and turbocharg...

  6. Fundamental combustion characteristics of lean hydrogen mixtures; Suiso kihaku kongoki no kisoteki nensho tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Barat, D.; Kido, H.; Nakahara, M.; Hashimoto, J. [Kyushu University, Fukuoka (Japan)

    1997-10-01

    One of the excellent combustion characteristics of hydrogen-air mixture is that its emission is free of CO2, but the problem of NOx remains, mainly caused by the high combustion temperature. Using leaner mixture and carrying out EGR are supposed to be effective methods to reduce NOx. In this study, to examine the effectiveness of the two methods, fundamental combustion characteristics of nitrogen added lean hydrogen mixtures were investigated by chemical equilibrium calculations and measurements of turbulent combustion characteristics. It is suggested that nitrogen added mixtures can achieve lower NOx combustion than lean mixtures, taking the combustion efficiency into consideration. 7 refs., 7 figs., 1 tab.

  7. Combustion characteristics and air pollutant formation during oxy-fuel co-combustion of microalgae and lignite.

    Science.gov (United States)

    Gao, Yuan; Tahmasebi, Arash; Dou, Jinxiao; Yu, Jianglong

    2016-05-01

    Oxy-fuel combustion of solid fuels is seen as one of the key technologies for carbon capture to reduce greenhouse gas emissions. The combustion characteristics of lignite coal, Chlorella vulgaris microalgae, and their blends under O2/N2 and O2/CO2 conditions were studied using a Thermogravimetric Analyzer-Mass Spectroscopy (TG-MS). During co-combustion of blends, three distinct peaks were observed and were attributed to C. vulgaris volatiles combustion, combustion of lignite, and combustion of microalgae char. Activation energy during combustion was calculated using iso-conventional method. Increasing the microalgae content in the blend resulted in an increase in activation energy for the blends combustion. The emissions of S- and N-species during blend fuel combustion were also investigated. The addition of microalgae to lignite during air combustion resulted in lower CO2, CO, and NO2 yields but enhanced NO, COS, and SO2 formation. During oxy-fuel co-combustion, the addition of microalgae to lignite enhanced the formation of gaseous species.

  8. On Cyclic Variability in a Residual Effected HCCI Engine with Direct Gasoline Injection during Negative Valve Overlap

    Directory of Open Access Journals (Sweden)

    Jacek Hunicz

    2014-01-01

    Full Text Available This study contributes towards describing the nature of cycle-by-cycle variability in homogeneous charge compression ignition (HCCI engines. Experimental measurements were performed using a single cylinder research engine operated in the negative valve overlap (NVO mode and fuelled with direct gasoline injection. Both stoichiometric and lean mixtures were applied in order to distinguish between different exhaust-fuel reactions during the NVO period and their propagation into the main event combustion. The experimental results show that the mode of cycle-by-cycle variability depends on the NVO phenomena. Under stoichiometric mixture conditions, neither variability in the main event indicated mean effective pressure (IMEP nor the combustion timing was affected by the NVO phenomena; however, long period oscillations in IMEP were observed. In contrast, for lean mixture, where fuel oxidation during the NVO period took place, distinctive correlations between NVO phenomena and the main event combustion parameters were observed. A wavelet analysis revealed the presence of both long-term and short-term oscillations in IMEP, in accordance with the extent of NVO phenomena. Characteristic patterns in IMEP were recognized using an in-house algorithm.

  9. Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

    KAUST Repository

    Singh, Eshan

    2017-03-28

    The blending of ethanol with primary reference fuel (PRF) mixtures comprising n-heptane and iso-octane is known to exhibit a non-linear octane response; however, the underlying chemistry and intermolecular interactions are poorly understood. Well-designed experiments and numerical simulations are required to understand these blending effects and the chemical kinetic phenomenon responsible for them. To this end, HCCI engine experiments were previously performed at four different conditions of intake temperature and engine speed for various PRF/ethanol mixtures. Transfer functions were developed in the HCCI engine to relate PRF mixture composition to autoignition tendency at various compression ratios. The HCCI blending octane number (BON) was determined for mixtures of 2-20 vol % ethanol with PRF70. In the present work, the experimental conditions were considered to perform zero-dimensional HCCI engine simulations with detailed chemical kinetics for ethanol/PRF blends. The simulations used the actual engine geometry and estimated intake valve closure conditions to replicate the experimentally measured start of combustion (SOC) for various PRF mixtures. The simulated HCCI heat release profiles were shown to reproduce the experimentally observed trends, specifically on the effectiveness of ethanol as a low temperature chemistry inhibitor at various concentrations. Detailed analysis of simulated heat release profiles and the evolution of important radical intermediates (e.g., OH and HO) were used to show the effect of ethanol blending on controlling reactivity. A strong coupling between the low temperature oxidation reactions of ethanol and those of n-heptane and iso-octane is shown to be responsible for the observed blending effects of ethanol/PRF mixtures.

  10. Experimental Studies on Combustion Characteristics of Mixed Municipal Solid Waste

    Institute of Scientific and Technical Information of China (English)

    Fan Jiang; Zhonggang Pan; Shi Liu; Haigang Wang

    2003-01-01

    In our country, municipal solid wastes (MSW) are always burnt in their original forms and only a few pretreatments are taken. Therefore it is vital to study the combustion characteristics of mixed waste. In this paper,thermogravimetric analysis and a lab scale fluidized bed facility were used as experimental means. The data in two different experimental systems were introduced and compared. It took MSW 3~3.5 rain to burn out in FB, but in thermogravimetric analyzer, the time is 20~25 min. It can be concluded that, in general, the behavior of a mixture of waste in TGA can be expressed by simple combination of individual components of the waste mixtures.Only minor deviations from the rule were observed. Yet, in Fluidized Bed, it was found that, for some mixtures,there was interference among the components during fluidized bed combustion.

  11. Mechanical durability and combustion characteristics of pellets from biomass blends

    Energy Technology Data Exchange (ETDEWEB)

    Gil, M.V.; Oulego, P.; Casal, M.D.; Pevida, C.; Pis, J.J.; Rubiera, F. [CSIC, Oviedo (Spain)

    2010-11-15

    Biofuel pellets were prepared from biomass (pine, chestnut and eucalyptus sawdust, cellulose residue, coffee husks and grape waste) and from blends of biomass with two coals (bituminous and semianthracite). Their mechanical properties and combustion behaviour were studied by means of an abrasion index and thermogravimetric analysis (TGA), respectively, in order to select the best raw materials available in the area of study for pellet production. Chestnut and pine sawdust pellets exhibited the highest durability, whereas grape waste and coffee husks pellets were the least durable. Blends of pine sawdust with 10-30% chestnut sawdust were the best for pellet production. Blends of cellulose residue and coals (<20%) with chestnut and pine sawdusts did not decrease pellet durability. The biomass/biomass blends presented combustion profiles similar to those of the individual raw materials. The addition of coal to the biomass in low amounts did not affect the thermal characteristics of the blends.

  12. Effects of Spark Ignition on HCCI Combustion in Gasoline Direct-Injection Engines%火花点火对缸内直喷汽油机HCCI燃烧的影响

    Institute of Scientific and Technical Information of China (English)

    王志; 王建昕; 帅石金; 马青峻

    2005-01-01

    实现汽油机均质混合气压燃(HCCI)的难点是着火控制.在缸内直喷汽油机上实现了HCCI燃烧,研究了火花点火对HCCI燃烧特性的影响.结果表明,HCCI燃烧方式较火花点火(SI)火焰传播燃烧方式放热速率快,热效率高,NOx大幅度降低.在HCCI临界状态时,火花点火有助于提高燃烧稳定性,抑制失火和爆燃,降低循环波动;当火花点火时缸内温度远超过临界着火温度时,火花点火对HCCI燃烧影响不大.火花点火在SI/HCCI燃烧模式切换工况时,能提高瞬态过渡平顺性.

  13. 催化燃烧对均质压燃发动机排放影响的数值模拟%Simulation of Influences of Catalytic Combustion on the Emissions of HCCI Engine

    Institute of Scientific and Technical Information of China (English)

    曾文; 解茂昭; 贾明

    2007-01-01

    通过耦合DETCHEM软件包及CHEMKIN软件包中的SENKIN模块,对活塞顶涂有催化剂的均质压燃(HCCI)发动机的燃烧过程进行了数值计算,建立了多区模型.利用此模型分析了催化燃烧对HCCI发动机缸内温度、热释放速率以及未燃碳氢化合物(UHC)、氮氧化合物(NOx)、一氧化碳(CO)排放的影响,结果表明催化燃烧能降低UHC、CO的排放,但NOx的排放会有所升高,对不弼催化剂及混合催化剂对HCCI发动机缸内温度、热释放速率以及UHC、NOx、CO排放的影响进行了探索,结果表明,和金属铂相比,以铑作催化剂时UHC的排放降低,但NOx、CO排放会有所升高;采用50%Pt-50%Rh的混合催化剂时,UHC、NOx的排放介于100%Pt与100%Rh之间,但CO的排放却比采用100%Pt与100%Rh时都要低.

  14. Chemical Kinetic Models for Advanced Engine Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Pitz, William J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mehl, Marco [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Westbrook, Charles K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-10-22

    The objectives for this project are as follows: Develop detailed chemical kinetic models for fuel components used in surrogate fuels for compression ignition (CI), homogeneous charge compression ignition (HCCI) and reactivity-controlled compression-ignition (RCCI) engines; and Combine component models into surrogate fuel models to represent real transportation fuels. Use them to model low-temperature combustion strategies in HCCI, RCCI, and CI engines that lead to low emissions and high efficiency.

  15. 均质压燃排放实验研究%An experimentalstudy of HCCI emission

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    A big challenge for engine design and reform at home and abroad is the more stringent emission regulations. Homogeneous Charge Compression Ignition (HCCI), as a new combustion mode, has provid-ed direction for the engines with low emission and broad vision for the design of internal combustion engine. Based on the HCCI experiment in a traditional diesel, the two-phase heat release for n-heptane is verified and the influences of the HCCI emissions on intake temperature and excess air coefficient are studied in the paper.%  更为严格的排放法规,是对国内外发动机设计与改造的巨大挑战。均质压燃(HCCI)作为一种新型燃烧模式,为低排放发动机提供了发展方向,也为内燃机设计提供了广阔视野。本文通过传统柴油机上的HCCI实验,验证了正庚烷的两阶段放热,并研究了进气温度和过量空气系数对HCCI排放的影响。

  16. Enabling HCCI modeling: The RIOT/CMCS Web Service for Automatic Reaction Mechanism Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Oluwole, O; Pitz, W J; Schuchardt, K; Rahn, L A; Green, Jr., W H; Leahy, D; Pancerella, C; Sj?berg, M; Dec, J

    2005-12-12

    New approaches are being developed to facilitate multidisciplinary collaborative research of Homogeneous Charge Compression Ignition (HCCI) combustion processes. In this paper, collaborative sharing of the Range Identification and Optimization Toolkit (RIOT) and related data and models is discussed. RIOT is a developmental approach to reduce the computational complexity of detailed chemical kinetic mechanisms, enabling their use in modeling kinetically-controlled combustion applications such as HCCI. These approaches are being developed and piloted as a part of the Collaboratory for Multiscale Chemical Sciences (CMCS) project. The capabilities of the RIOT code are shared through a portlet in the CMCS portal that allows easy specification and processing of RIOT inputs, remote execution of RIOT, tracking of data pedigree and translation of RIOT outputs (such as the reduced model) to a table view and to the commonly-used CHEMKIN mechanism format. The reduced model is thus immediately ready to be used for more efficient simulation of the chemically reacting system of interest. This effort is motivated by the need to improve computational efficiency in modeling HCCI systems. Preliminary use of the web service to obtain reduced models for this application has yielded computational speedup factors of up to 20 as presented in this paper.

  17. Combustion characteristics of red alder sawdust. Technical Progress Report No. 3

    Energy Technology Data Exchange (ETDEWEB)

    Junge, D.C.

    1978-12-01

    Significant quantities of wood resdiue fuels are presently being used in industrial steam generating facilities. Recent studies indicate that substantial additional quantities of wood residue fuels are available for energy generation in the form of steam and/or electricity. A limited data base on the combustion characteristics of wood residue fuels has resulted in the installation and operation of inefficient combustion systems for these fuels. This investigation of the combustion characteristics of wood residue fuels was undertaken to provide a data base which could be used to optimize the combustion of such fuels. Optimization of the combustion process in industrial boilers serves to improve combustion efficiency and to reduce air pollutant emissions generated in the combustion process. Data are presented on the combustion characteristics of red alder sawdust.

  18. Review of Combustion Stability Characteristics of Swirl Coaxial Element Injectors

    Science.gov (United States)

    Hulka, J. R.; Casiano, M. J.

    2013-01-01

    Liquid propellant rocket engine injectors using coaxial elements where the center liquid is swirled have become more common in the United States over the past several decades, although primarily for technology or advanced development programs. Currently, only one flight engine operates with this element type in the United States (the RL10 engine), while the element type is very common in Russian (and ex-Soviet) liquid propellant rocket engines. In the United States, the understanding of combustion stability characteristics of swirl coaxial element injectors is still very limited, despite the influx of experimental and theoretical information from Russia. The empirical and theoretical understanding is much less advanced than for the other prevalent liquid propellant rocket injector element types, the shear coaxial and like-on-like paired doublet. This paper compiles, compares and explores the combustion stability characteristics of swirl coaxial element injectors tested in the United States, dating back to J-2 and RL-10 development, and extending to very recent programs at the NASA MSFC using liquid oxygen and liquid methane and kerosene propellants. Included in this study are several other relatively recent design and test programs, including the Space Transportation Main Engine (STME), COBRA, J-2X, and the Common Extensible Cryogenic Engine (CECE). A presentation of the basic data characteristics is included, followed by an evaluation by several analysis techniques, including those included in Rocket Combustor Interactive Design and Analysis Computer Program (ROCCID), and methodologies described by Hewitt and Bazarov.

  19. Combustion Characteristics of Liquid Normal Alkane Fuels in a Model Combustor of Supersonic Combustion Ramjet Engine

    Science.gov (United States)

    今村, 宰; 石川, 雄太; 鈴木, 俊介; 福本, 皓士郎; 西田, 俊介; 氏家, 康成; 津江, 光洋

    Effect of kinds of one-component n-alkane liquid fuels on combustion characteristics was investigated experimentally using a model combustor of scramjet engine. The inlet condition of a model combustor is 2.0 of Mach number, up to 2400K of total temperature, and 0.38MPa of total pressure. Five kinds of n-alkane are tested, of which carbon numbers are 7, 8, 10, 13, and 16. They are more chemically active and less volatile with an increase of alkane carbon number. Fuels are injected to the combustor in the upstream of cavity with barbotage nitrogen gas and self-ignition performance was investigated. The result shows that self-ignition occurs with less equivalence ratio when alkane carbon number is smaller. This indicates that physical characteristic of fuel, namely volatile of fuel, is dominant for self-ignition behavior. Effect on flame-holding performance is also examined with adding pilot hydrogen and combustion is kept after cutting off pilot hydrogen with the least equivalence ratio where alkane carbon number is from 8 to 10. These points are discussed qualitatively from the conflict effect of chemical and physical properties on alkane carbon number.

  20. Development of HCCI Engines for Dimethyl Ether

    DEFF Research Database (Denmark)

    Hansen, Kim Rene; Pedersen, Troels Dyhr; Schramm, Jesper

    This report has been prepared for the Danish Energy Agency. It summarizes the results of the project entitled: “Development of HCCI engines for DME”. The project has been financed by “EFP 06”. The chapters about theoretical and experimental studies have been written using the language...

  1. Numerical investigations on HCCI engine with increased induction induced swirl and engine speed

    Institute of Scientific and Technical Information of China (English)

    T. Karthikeya Sharma; G. Amba Prasad Rao; K. Madhu Murthy

    2015-01-01

    Homogeneous charge compression ignition (HCCI) mode of combustion is popularly known for achieving simultaneous reduction of NOx as well as soot emissions as it combines the compression ignition (CI) and spark ignition (SI) engine features. In this work, a CI engine was simulated to work in HCCI mode and was analyzed to study the effect of induction induced swirl under varying speeds using three-zone extended coherent flame combustion model (ECFM-3Z, compression ignition) of STAR-CD. The analysis was done considering speed ranging from 800 to 1600 r/min and swirl ratios from 1 to 4. The present study reveals that ECFM-3Z model has well predicted the performance and emissions of CI engine in HCCI mode. The simulation predicts reduced in-cylinder pressures, temperatures, wall heat transfer losses, and piston work with increase in swirl ratio irrespective of engine speed. Also, simultaneous reduction in CO2 and NOx emissions is realized with higher engine speeds and swirl ratios. Low speeds and swirl ratios are favorable for low CO2 emissions. It is observed that increase in engine speed causes a marginal reduction in in-cylinder pressures and temperatures. Also, higher turbulent energy and velocity magnitude levels are obtained with increase in swirl ratio, indicating efficient combustion necessitating no modifications in combustion chamber design. The investigations reveal a total decrease of 38.68% in CO2 emissions and 12.93% in NOx emissions when the engine speed increases from 800 to 1600 r/min at swirl ratio of 4. Also an increase of 14.16% in net work done is obtained with engine speed increasing from 800 to 1600 r/min at swirl ratio of 1. The simulation indicates that there is a tradeoff observed between the emissions and piston work. It is finally concluded that the HCCI combustion can be regarded as low temperature combustion as there is significant decrease in in-cylinder temperatures and pressures at higher speeds and higher swirl ratios.

  2. Investigation of JP-8 Autoignition Under Vitiated Combustion Conditions

    Science.gov (United States)

    2011-01-01

    combustion engines and HCCI systems rather than low pressure combustion devices that are of interest in the current study. This data provides insight...2011 Directed by: Professor Gregory Jackson, Chair Department of Mechanical Engineering Limited data on jet fuel ignition and oxidation at...Fuller 2011 ii Acknowledgements This research has been supported and funded by Combustion Science and Engineering , Inc. through the following

  3. An experimental study of different hydrocarbon components in natural gas and their impact on engine performance in a HCCI engine

    Energy Technology Data Exchange (ETDEWEB)

    Aaberg, Kristoffer

    2000-07-01

    Natural gas is a well suited fuel for HCCI (Homogenous Charge Compression Ignition) operation. Commercial natural gas consists of many different hydrocarbons where the lighter hydrocarbons, methane, ethane propane and butane are the most common and methane having the highest percentage. The composition of natural gas varies widely all over the world. It is well known that the higher hydrocarbons have a great impact on the ignition characteristics. As a spontaneous auto-ignition process initiates HCCI, this type of engine is very sensitive of the fuels ignition characteristics. To investigate the influence of the higher hydrocarbons an extensive test series was carried out. The impact of different concentrations of ethane, propane, iso- and n-butane were tested. Using different equivalence ratios, concentrations of the hydrocarbons, levels of EGR and levels of boost pressure the tests were carried out. Data collected during the testing were emission, mass flow, indicated mean effective pressure, inlet temperature and engine speed. From these data, specific emissions and efficiencies could be calculated. As a test a value of released heat per cycle was also evaluated, and used to check the mass flow. The results show that the ignition characteristics of the charge is very sensitive to fuel composition. A strong connection between the required inlet air temperature and the fuel composition was detected. With an increasing amount of heavier components in the gas, this temperature was decreased. This is connected to the octane number of the components. Much of the engine performance can be related to this change of temperature. Emissions and power output (imep) showed the highest dependency of the concentration of component gas. Butanes had the highest impact on the inlet temperature, followed by propane and ethane. With the use of 20% EGR the inlet temperature had to be raised. The impact of the component gases was the same as with no EGR. The combustion efficiency

  4. Imaging Studies of the Effects of Ethanol/Gasoline Blends on Spark-Assisted HCCI

    Science.gov (United States)

    Fatouraie, Mohammad; Wooldridge, Margaret

    2012-10-01

    Spark assist (SA) has been demonstrated to extend the operating limits of homogeneous charge compression ignition (HCCI) modes of engine operation. This experimental investigation focuses on the effects caused by the SA HCCI operation on ignition and combustion properties of 100% indolene and 70% indolene/30% ethanol blends. The spark assist effects are compared to base line HCCI for each blend by varying spark timing at different fuel/air equivalence ratio (φ= 0.4--0.6). High speed imaging is used to understand the effects of flame propagation on heat release rates. Ethanol generally improves engine performance with higher indicated mean effective pressure (IMEP) and higher stability compared to 100% indolene. SA advances phasing within a range of 5 CAD at lower engine speeds (700 rpm) and 11 CAD at higher engine speeds (1200 rpm). SA does not affect heat release rates until immediately (within 5 CAD) prior to autoignition. Unlike previous studies, flames were not observed for all SA conditions. During SA operation, more fuel mass was burned by flame propagation with gasoline compared to E30.

  5. An extended multi-zone combustion model for PCI simulation

    Science.gov (United States)

    Kodavasal, Janardhan; Keum, SeungHwan; Babajimopoulos, Aristotelis

    2011-12-01

    Novel combustion modes are becoming an important area of research with emission regulations more stringent than ever before, and with fuel economy being assigned greater importance every day. Homogeneous Charge Compression Ignition (HCCI) and Premixed Compression Ignition (PCI) modes in particular promise better fuel economy and lower emissions in internal combustion engines. Multi-zone combustion models have been popular in modelling HCCI combustion. In this work, an improved multi-zone model is suggested for PCI combustion modelling. A new zoning scheme is suggested based on incorporating the internal energy of formation into an earlier conventional HCCI multi-zone approach, which considers a two-dimensional reaction space defined by equivalence ratio and temperature. It is shown that the added dimension improves zoning by creating more representative zones, and thus reducing errors compared to the conventional zoning approach, when applied to PCI simulation.

  6. Numerical analysis of combustion characteristics of hybrid rocket motor with multi-section swirl injection

    Science.gov (United States)

    Li, Chengen; Cai, Guobiao; Tian, Hui

    2016-06-01

    This paper is aimed to analyse the combustion characteristics of hybrid rocket motor with multi-section swirl injection by simulating the combustion flow field. Numerical combustion flow field and combustion performance parameters are obtained through three-dimensional numerical simulations based on a steady numerical model proposed in this paper. The hybrid rocket motor adopts 98% hydrogen peroxide and polyethylene as the propellants. Multiple injection sections are set along the axis of the solid fuel grain, and the oxidizer enters the combustion chamber by means of tangential injection via the injector ports in the injection sections. Simulation results indicate that the combustion flow field structure of the hybrid rocket motor could be improved by multi-section swirl injection method. The transformation of the combustion flow field can greatly increase the fuel regression rate and the combustion efficiency. The average fuel regression rate of the motor with multi-section swirl injection is improved by 8.37 times compared with that of the motor with conventional head-end irrotational injection. The combustion efficiency is increased to 95.73%. Besides, the simulation results also indicate that (1) the additional injection sections can increase the fuel regression rate and the combustion efficiency; (2) the upstream offset of the injection sections reduces the combustion efficiency; and (3) the fuel regression rate and the combustion efficiency decrease with the reduction of the number of injector ports in each injection section.

  7. Combustion characteristics of SMX and SMX based propellants

    Science.gov (United States)

    Reese, David A.

    This work investigates the combustion of the new solid nitrate ester 2,3-hydroxymethyl-2,3-dinitro-1,4-butanediol tetranitrate (SMX, C6H 8N6O16). SMX was synthesized for the first time in 2008. It has a melting point of 85 °C and oxygen balance of 0% to CO 2, allowing it to be used as an energetic additive or oxidizer in solid propellants. In addition to its neat combustion characteristics, this work also explores the use of SMX as a potential replacement for nitroglycerin (NG) in double base gun propellants and as a replacement for ammonium perchlorate in composite rocket propellants. The physical properties, sensitivity characteristics, and combustion behaviors of neat SMX were investigated. Its combustion is stable at pressures of up to at least 27.5 MPa (n = 0.81). The observed flame structure is nearly identical to that of other double base propellant ingredients, with a primary flame attached at the surface, a thick isothermal dark zone, and a luminous secondary flame wherein final recombination reactions occur. As a result, the burning rate and primary flame structure can be modeled using existing one-dimensional steady state techniques. A zero gas-phase activation energy approximation results in a good fit between modeled and observed behavior. Additionally, SMX was considered as a replacement for nitroglycerin in a double base propellant. Thermochemical calculations indicate improved performance when compared with the common double base propellant JA2 at SMX loadings above 40 wt-%. Also, since SMX is a room temperature solid, migration may be avoided. Like other nitrate esters, SMX is susceptible to decomposition over long-term storage due to the presence of excess acid in the crystals; the addition of stabilizers (e.g., derivatives of urea) during synthesis should be sufficient to prevent this. the addition of Both unplasticized and plasticized propellants were formulated. Thermal analysis of unplasticized propellant showed a distinct melt

  8. Combustion and sensitivity characteristics of Mg/TF pyrolants

    Energy Technology Data Exchange (ETDEWEB)

    Kuwahara, T.; Matsuo, S.; Shinozaki, N. [Aerospace Division, Nissan Motor Co Ltd, Saitama (Japan)

    1996-12-31

    Burning rate and sensitivity characteristics of energetic mixtures composed of metal particles and oxidizers, the so called `pyrolants`, were studied experimentally. The pyrolants tested were made of various particle sizes of magnesium (Mg) and poly-tetrafluoroethylene (TF). Mg/TF pyrolant produces high combustion flame temperature, so it is used as heat sources and igniter pyrolants. The maximum flame temperature (Tf) of Mg/TF pyrolant is 3271 K at 0.1 MPa, and 3483 K at 1 MPa. These values are obtained when Mg concentration is 30 %. When the Mg concentrations are less than 50 %, the pyrolants are not able to burn stably at one atmosphere. The burning rate increases with increasing concentration of Mg and decreases with increasing the mean diameter of Mg particles at constant pressure. Sensitivity characteristics were evaluated with drop hammer test and the weight used was 5 kg. Explosive energy decreased with increasing burning rate, so there is strong relationship between burning rate and explosive energy. (authors) 8 refs.

  9. Multi-dimensional modeling of the application of catalytic combustion to homogeneous charge compression ignition engine

    Science.gov (United States)

    Zeng, Wen; Xie, Maozhao

    2006-12-01

    The detailed surface reaction mechanism of methane on rhodium catalyst was analyzed. Comparisons between numerical simulation and experiments showed a basic agreement. The combustion process of homogeneous charge compression ignition (HCCI) engine whose piston surface has been coated with catalyst (rhodium and platinum) was numerically investigated. A multi-dimensional model with detailed chemical kinetics was built. The effects of catalytic combustion on the ignition timing, the temperature and CO concentration fields, and HC, CO and NOx emissions of the HCCI engine were discussed. The results showed the ignition timing of the HCCI engine was advanced and the emissions of HC and CO were decreased by the catalysis.

  10. HCCI Intelligent Rapid Modeling by Artificial Neural Network and Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    AbdoulAhad Validi

    2012-01-01

    Full Text Available A Dynamic model of Homogeneous Charge Compression Ignition (HCCI, based on chemical kinetics principles and artificial intelligence, is developed. The model can rapidly predict the combustion probability, thermochemistry properties, and exact timing of the Start of Combustion (SOC. A realization function is developed on the basis of the Sandia National Laboratory chemical kinetics model, and GRI3.0 methane chemical mechanism. The inlet conditions are optimized by Genetic Algorithm (GA, so that combustion initiates and SOC timing posits in the desired crank angle. The best SOC timing to achieve higher performance and efficiency in HCCI engines is between 5 and 15 degrees crank angle (CAD after top dead center (TDC. To achieve this SOC timing, in the first case, the inlet temperature and equivalence ratio are optimized simultaneously and in the second case, compression ratio is optimized by GA. The model’s results are validated with previous works. The SOC timing can be predicted in less than 0.01 second and the CPU time savings are encouraging. This model can successfully be used for real engine control applications.

  11. Ignition and combustion characteristics of molded amorphous boron under different oxygen pressures

    Science.gov (United States)

    Liang, Daolun; Liu, Jianzhong; Zhou, Yunan; Zhou, Junhu; Cen, Kefa

    2017-09-01

    Ignition and combustion characteristics of amorphous boron (B) have received much attention from researchers in recent decades. A pressurized concentrated ignition experimental system was designed to evaluate the ignition and combustion characteristics of molded B samples. The ignition experiments were carried out under different oxygen pressures (1-9 atm). The condensed combustion products were then analyzed using a scanning electron microscope, an X-ray energy dispersive spectrometer, and an X-ray diffractometer. Furthermore, the complete oxidation rates of the samples were detected by inductively coupled plasma chromatography. As the oxygen pressure increased, the combustion intensity of the samples steadily increased, and the ignition delay time and combustion time both decreased. Under the oxygen pressure of 9 atm, the average ignition delay time and combustion time were 2640 ms and 2596 ms, respectively, and the highest combustion temperature reached 1561.5 °C. The initial diffusion flame on the sample surface was green and the brightest, which was produced by an intermediate combustion product, BO2 (corresponding molecular emission spectrum wavelength, 547.3 nm). Emission spectra of another intermediate product, BO (431.9 nm) was also detected. Two different types of structures were found in the condensed combustion products of the samples. The first type was the flaky B2O3 structure, and the second type was the flocculent structure of incomplete combustion products. The B2O3 content in the condensed combustion products increased with the oxygen pressure during combustion. The complete oxidation ratio of the samples also increased with the oxygen pressure, and reached the maximum value of 68.71% under 9 atm. Overall, the samples showed better ignition and combustion characteristics under higher oxygen pressure.

  12. Experimental facility for analysis of biomass combustion characteristics

    Directory of Open Access Journals (Sweden)

    Miljković Biljana M.

    2015-01-01

    Full Text Available The objective of the present article is to present an experimental facility which was designed and built at the Faculty of Technical Sciences in order to study the combustion of different sorts of biomass and municipal solid waste. Despite its apparent simplicity, direct combustion is a complex process from a technological point of view. Conventional combustion equipment is not designed for burning agricultural residues. Devices for agricultural waste combustion are still in the development phase, which means that adequate design solution is presently not available at the world market. In order to construct a boiler and achieve optimal combustion conditions, it is necessary to develop a mathematical model for biomass combustion. Experimental facility can be used for the collection of data necessary for detailed modelling of real grate combustor of solid biomass fuels. Due to the complexity of the grate combustion process, its mathematical models and simulation software tools must be developed and verified using experimental data. This work highlights the properties required for the laboratory facility designed for the examination of biomass combustion and discusses design and operational issues.

  13. HCCI甲醇发动机的燃烧与排放特性%Combustion and Emission Characteristics of HCCI Engine Fueled with Methanol Fuel

    Institute of Scientific and Technical Information of China (English)

    陈韬; 何邦全; 谢辉; 赵华

    2007-01-01

    在Ricardo Hydra 单缸四冲程发动机上利用内部废气再循环策略实现了甲醇燃料的HCCI燃烧.通过调整HCCI发动机的过量空气系数和转速,研究了HCCI甲醇发动机的燃烧和排放特性.结果表明,甲醇燃料的HCCI燃烧不同于普通汽油,其着火更早、燃烧更快,但在低转速时,平均指示压力相对较低.甲醇燃料可以在更稀的混合气条件下实现HCCI燃烧.在相同的转速和过量空气系数下,甲醇燃料的NOx和HC排放低于汽油.

  14. Characterisation of refuse-derived fuels on the basis of their combustion characteristics; Charakterisierung von Ersatzbrennstoffen hinsichtlich brennstofftechnischer Eigenschaften

    Energy Technology Data Exchange (ETDEWEB)

    Beckmann, M.; Ncube, S. [Bauhaus Univ. Weimer (Germany). Lehrstuhl Verfahren und Umwelt

    2007-07-01

    Refuse-derived fuels and biomass-derived fuels are used in power stations and industrial production processes, either in monocombustion plants or in cocombustion plants. Their energy content, ignition and combustion characteristics, slag formation and corrosion potential make them difficult fuels. The contribution starts by reviewing the combustion characteristics of refuse-derived and biomass-derived fuels and analyzing their influence on the combustion characteristics. Various methods of defining the combustion characteristics of these fuels are explained. (orig.)

  15. Study on combustion characteristics of petroleum coke residual oil slurry

    Energy Technology Data Exchange (ETDEWEB)

    Shou Weiyi; Xu Xiaoming; Cao Xinyu [and others

    1997-07-01

    Petroleum coke residual oil slurry (POS) is one of prospect substitute of oil burned in many industrial boilers and utilities in China. It is a mixture of pulverized petroleum coke, residual oil and slurry oil. We carried out a series of experiments to study its ignition and combustion mechanism. Experimental results show that the ignition temperature of petroleum coke is higher than normal anthracite and meager coal, and it is difficult to be burned in oil-fired furnace directly. The petroleum coke`s combustion property is improved greatly after mixing with residual oil and slurry oil. The combustion process of POS can be divided into three phases: preheating, kindling and homogenous combustion, burning of the petroleum coke residue. The combustion condition of POS is close to bituminous and coal-oil-mixture (COM).

  16. Using biofuel tracers to study alternative combustion regimes

    Science.gov (United States)

    Mack, J. H.; Flowers, D. L.; Buchholz, B. A.; Dibble, R. W.

    2007-06-01

    Interest in the use of alternative fuels and engines is increasing as the price of petroleum climbs. The inherently higher efficiency of Diesel engines has led to increased adoption of Diesels in Europe, capturing approximately 40% of the new passenger car market. Unfortunately, lower CO2 emissions are countered with higher nitrogen oxides (NOx) and particulate matter (PM) emissions and higher noise. Adding oxygenated compounds to the fuel helps reduce PM emissions. However, relying on fuel alone to reduce PM is unrealistic due to economic constraints and difficult due to the emerging PM standards. Keeping peak combustion temperature below 1700 K inhibits NOx formation. Altering the combustion regime to burn at temperatures below the NOx threshold and accept a wide variety of fuels seems like a promising alternative for future engines. Homogeneous charge compression ignition (HCCI) is a possible solution. Fuel and air are well mixed prior to intake into a cylinder (homogeneous charge) and ignition occurs by compression of the fuel-air mixture by the piston. HCCI is rapid and relatively cool, producing little NOx and PM. Unfortunately, it is hard to control since HCCI is initiated by temperature and pressure instead of a spark or direct fuel injection. We investigate biofuel HCCI combustion, and use intrinsically labeled biofuels as tracers of HCCI combustion. Data from tracer experiments are used to improve our combustion modeling.

  17. Influence of limestone fillers on combustion characteristics of asphalt mortar for pavements

    DEFF Research Database (Denmark)

    Ke, Wu; Kai, Zhu; Wu, Hao;

    2014-01-01

    Asphalt materials will be ignited and release significant toxic fumes within tunnel fires. Thus, combustion characteristics of asphalt materials used in road tunnel should be studied in order to limit such an adverse effect. In the present work we study the influence of limestone fillers...... on combustion characteristics of asphalt mortar by thermogravimetric and kinetic analysis. It is shown that the combustion of asphalt mortar is not just a linear superposition of asphalt and limestone. The limestone will increase the ignition point and the activation energy of the primary volatile release......, and will catalyze the char formation from the primary volatile release. Kinetic analysis shows that the primary volatile release stage of asphalt mortar combustion can be explained by a three-dimensional diffusion model, the secondary volatile release and char combustion stage can be explained by a model under...

  18. Combustion characteristics and arsenic retention during co-combustion of agricultural biomass and bituminous coal.

    Science.gov (United States)

    Zhou, Chuncai; Liu, Guijian; Wang, Xudong; Qi, Cuicui; Hu, Yunhu

    2016-08-01

    A combination of thermogravimetric analysis (TG) and laboratory-scale circulated fluidized bed combustion experiment was conducted to investigate the thermochemical, kinetic and arsenic retention behavior during co-combustion bituminous coal with typical agricultural biomass. Results shown that ignition performance and thermal reactivity of coal could be enhanced by adding biomass in suitable proportion. Arsenic was enriched in fly ash and associated with fine particles during combustion of coal/biomass blends. The emission of arsenic decreased with increasing proportion of biomass in blends. The retention of arsenic may be attributed to the interaction between arsenic and fly ash components. The positive correlation between calcium content and arsenic concentration in ash suggesting that the arsenic-calcium interaction may be regarded as the primary mechanism for arsenic retention.

  19. Effect of Nitrate Ester on the Combustion Characteristics of PET/HMX -based Propellants

    National Research Council Canada - National Science Library

    Yunlan Sun; Baozhong Zhu; Shufen Li

    2011-01-01

    The effect of nitrate ester NG/TEGDN on the combustion characteristics of PET/HMX-based propellants has been experimentally investigated using of high-speed photography technique and scanning electron microscopy...

  20. Combustion characteristics of Ponderosa Pine bark. Technical progress report No. 7, September 16, 1977--September 15, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Junge, D.C.

    1978-12-01

    Significant quantities of wood residue fuels are presently being used in industrial steam generating facilities. Recent studies indicate that substantial additional quantities of wood residue fuels are available for energy generation in the form of steam and/or electricity. A limited data base on the combustion characteristics of wood residue fuels has resulted in the installation and operation of inefficient combustion systems for these fuels. This investigation of the combustion characteristics of wood residue fuels was undertaken to provide a data base which could be used to optimize the combustion of such fuels. Optimization of the combustion process in industrial boilers serves to improve combustion efficiency and to reduce air pollutant emissions generated in the combustion process. Data are presented on the combustion characteristics of Ponderosa Pine bark. The data were obtained in a pilot scale combustion test facility at Oregon State University.

  1. Investigation of spray characteristics from a low-pressure common rail injector for use in a homogeneous charge compression ignition engine

    Science.gov (United States)

    Lee, Kihyung; Reitz, Rolf D.

    2004-03-01

    Homogeneous charge compression ignition (HCCI) combustion provides extremely low levels of pollutant emissions, and thus is an attractive alternative for future IC engines. In order to achieve a uniform mixture distribution within the engine cylinder, the characteristics of the fuel spray play an important role in the HCCI engine concept. It is well known that high-pressure common rail injection systems, mainly used in diesel engines, achieve poor mixture formation because of the possibility of direct fuel impingement on the combustion chamber surfaces. This paper describes spray characteristics of a low-pressure common rail injector which is intended for use in an HCCI engine. Optical diagnostics including laser diffraction and phase Doppler methods, and high-speed camera photography, were applied to measure the spray drop diameter and to investigate the spray development process. The drop sizing results of the laser diffraction method were compared with those of a phase Doppler particle analyser (PDPA) to validate the accuracy of the experiments. In addition, the effect of fuel properties on the spray characteristics was investigated using n-heptane, Stoddard solvent (gasoline surrogate) and diesel fuel because HCCI combustion is sensitive to the fuel composition. The results show that the injector forms a hollow-cone sheet spray rather than a liquid jet, and the atomization efficiency is high (small droplets are produced). The droplet SMD ranged from 15 to 30 µm. The spray break-up characteristics were found to depend on the fuel properties. The break-up time for n-heptane is shorter and the drop SMD is smaller than that of Stoddard solvent and diesel fuel.

  2. Experimental and numerical analysis of the performance and exhaust gas emissions of a biogas/n-heptane fueled HCCI engine

    KAUST Repository

    Kozarac, Darko

    2016-09-12

    The use of highly reactive fuel as an ignition promoter enables operation of biogas fueled homogeneous charge compression ignition (HCCI) engine at low intake temperatures with practical control of combustion phasing. In order to gain some insight into this operation mode the influence of addition of n-heptane on combustion, performance, emissions and control of combustion phasing of a biogas fueled HCCI engine is experimentally researched and presented in this paper. Additionally, the performance analysis of the practical engine solution for such operation is estimated by using the numerical simulation of entire engine. The results showed that the introduction of highly reactive fuel results with a significant change in operating conditions and with a change in optimum combustion phasing. The addition of n-heptane resulted in lower nitrogen oxides and increased carbon monoxide emissions, while the unburned hydrocarbons emissions were strongly influenced by combustion phasing and at optimal conditions are lowered compared to pure biogas operation. The results also showed a practical operation range for strategies that use equivalence ratio as a control of load. Simulation results showed that the difference in performance between pure biogas and n-heptane/biogas operation is even greater when the practical engine solution is taken into account.

  3. Experimental investigation on the combustion characteristics of aluminum in air

    Science.gov (United States)

    Feng, Yunchao; Xia, Zhixun; Huang, Liya; Yan, Xiaoting

    2016-12-01

    With the aim of revealing the detailed process of aluminum combustion in air, this paper reports an experimental study on the combustion of aluminum droplets. In this work, the aluminum wires were exposed and heated by a CO2 laser to produce aluminum droplets, and then these droplets were ignited and burnt in air. The changing processes of aluminum wires, droplets and flames were directly recorded by a high-speed camera, which was equipped with a high magnification zoom lens. Meanwhile, the spectrum distribution of the flame was also registered by an optical spectrometer. Besides, burning residuals were collected and analyzed by the methods of Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS). Experimental results show that, during combustion, the aluminum droplet is covered by a spherical vapor-phase flame, and the diameter of this flame is about 1.4 times of the droplet diameter, statistically. In the later stages of combustion, the molten aluminum and condensed oxide products can react to generate gaseous Al and Al2O spontaneously. Little holes are found on the surface of residuals, which are the transport channels of gaseous products, namely the gaseous Al and Al2O. The combustion residuals are consisted by lots of aluminum oxide particles with diameters less than 1 μm.

  4. Influence of Ti Powder Characteristics on Combustion Synthesis of Porous NiTi Alloy

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Porous NiTi shape memory alloy (SMA) is a novel biomedical material used for human hard tissue implant. The influence of elemental titanium powder characteristics such as powder morphology, particle size and specific surface area (SSA) on the minimal ignition temperature, combustion temperature and final product of porous NiTi SMA fabricated by combustion synthesis method was investigated in this paper by scanning electron microscopy (SEM)and laser diffraction. The preliminary data indicated that the titanium powder characteristics had a strong effect on combustion synthesis of porous NiTi SMA.

  5. Combustion characteristics of Methanol-base fuel(MBF)made by coal

    Institute of Scientific and Technical Information of China (English)

    ZHANG Quan; ZHAO Cong-cong; LIU Yang

    2011-01-01

    Profound experimental research was made on Methanol-base fuel(MBF)mainly consisting of methanol,and the results were compared with that of diesel oil.Their respective combustion characteristics of caloric value,combustion efficiency and components of smoke were synthetically analyzed by employing the electronic weighing devices,the rotor flow-meter,intelligent flue gas analyzer,advanced bomb calorimeter,etc.,referring to the feasibility of taking it as a fuel for general use.Experiment results show that Methanol-base fuel not only has superiorities on combustion characteristics but also bears energy saving and environmental protection advantages.

  6. Slagging characteristics of molten coal ash on silicon-aluminum combustion liners of boiler

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to study the slagging characteristics of boiler combustion liners during pulverized coal stream combustion,the slag samples on the surface of combustion liner were investigated by X-ray diffractometry,scan electron microscopy and energy dispersive X-ray analysis,and the transformation characteristics of the compositions and crystal phases were studied.The results show that the size of slag granules decreases as the slagging temperature increases;the crystallinity of coal ash I reduces to about 48.6% when the temperature is increased up to 1 350 ℃,and that of the coal ash Ⅱ reduces to about 65% when the temperature is increased up to 1 500 ℃;the encroachment of molten coal ash to the combustion liner is strengthened.At the same time,the diffusion and the segregation of the compositions in combustion liners have selectivity,which is in favor of enhancing the content of crystal phases,weakening the conglutination among molten slag compositions and combustion liner,and avoiding yielding big clinkers.But the diffusion of the compositions in combustion liners increases the porosity and decreases the mechanical intensity of combustion liner,and makes the slag encroachment to the liner become more serious.

  7. Combustion characteristics of an SI engine fueled with biogas fuel

    Science.gov (United States)

    Chen, Lei; Long, Wuqiang; Song, Peng

    2017-04-01

    An experimental research of the effect of H2 substitution and CO2 dilution on CH4 combustion has been carried out on a spark ignition engine. The results show that H2 addition could improve BMEP, thermal efficiency, CO and THC emissions. NOX emissions increased for higher low heating value (LHV) of H2 than CH4. CO2 dilution could effective reduce NOX emission of H2-CH4 combustion. Although engine performance, thermal efficiency and exhaust get unacceptable under high fuel dilution ratio (F.D.R.) conditions, it could be solved by decreasing F.D.R. and/or increasing hydrogen substitution ratio (H.S.R.).

  8. Investigation of thermal and environmental characteristics of combustion of gaseous fuels

    Science.gov (United States)

    Vetkin, A. V.; Suris, A. L.

    2015-03-01

    Numerical investigations are fulfilled for some thermal and environmental characteristics of combustion of gaseous fuels used at present in tube furnaces of petroleum refineries. The effect of the fuel composition on these characteristics is shown and probable consequences of the substitution of natural gas to other types of fuels. Methane, ethane, propane, butane, propylene, and hydrogen are considered for comparison, which in most cases are constituents of the composition of the fuel burnt in furnaces. The effect of the fuel type, its associated combustion temperature, combustion product emissivity, temperature of combustion chamber walls, mean beam length, and heat release on the variation in the radiant heat flux within the radiant chamber of furnaces is investigated. The effect of flame characteristics, which are determined by the presence of diffusion combustion zones formed by burners used at present in furnaces for reducing nitrogen oxides emission, is analyzed. The effect of the fuel type on the equilibrium NO concentration is also investigated. The investigations were carried out both at arbitrary given gas temperatures and at effective temperatures dependent on the adiabatic combustion temperature and the temperature at the chamber output and determined based on solving a set of equations at various heat-release rates of the combustion chamber.

  9. Compositional Simulation of In-Situ Combustion EOR: A Study of Process Characteristics

    DEFF Research Database (Denmark)

    Jain, Priyanka; Stenby, Erling Halfdan; von Solms, Nicolas

    2010-01-01

    and multidisciplinary process data. This paper extends the understanding of previous research done in this domain by performing the process simulations to study further the impact of oxidation reactions and combustion reactions of crude oils along with their saturate, aromatic, resin, and asphaltene (SARA) fractions......In order to facilitate the study of the influence of reservoir process characteristics in In-Situ combustion modeling and advance the work of Kristensen et al. in this domain; a fully compositional In-situ combustion (ISC) model of Virtual Kinetic Cell (VKC; single-cell model) for laboratory scale...... combustion simulation is used. Preceding research work primarily focused on a kinetic model that was based on six components and incorporated four chemical reactions. However, modeling of a thermal process as complex as In-situ combustion requires in-depth understanding of detailed reaction kinetics...

  10. Research on combustion characteristics of bio-oil from sewage sludge

    Institute of Scientific and Technical Information of China (English)

    Rui LI; Baosheng JIN; Xiangru JIA; Zhaoping ZHONG; Gang XIAO; Xufeng FU

    2009-01-01

    Combustion characteristics of bio-oil from sewage sludge were investigated using thermograviMetry (TG) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques. The combustion process could be divided into two weight loss stages. Light compounds volatilized and were oxidized in the first stage and the heterogeneous combustion between oxygen and heavy compounds happened in the second stage, which were confirmed by FT-IR technique. Most weight loss occurred in the first stage. The effect of heating rate was also studied and higher heating rates were found to facilitate the combustion process. The kinetic parameters of the two stages were calculated and the change of activation energy indicated higher heating rates benefited combustion.

  11. 醇醚双燃料HCCI燃烧机理研究%HCCI Mechanism of Methanol/DME Dual Fuel

    Institute of Scientific and Technical Information of China (English)

    陈鹏; 孟忠伟; 张煜盛; 闫妍; 吴怡

    2014-01-01

    The detail mechanism of dimethyl ether (CH3OCHO) and methanol (CH3OH) was simplified by the method of sensitivity analysis and the reduced chemical kinetic model of methanol/DME HCCI was established .The model included 38 speciesand99elementreactionsandformaldehyde(CH2O),formicacid(HCO2H)andmethylformateformation(CH3OCHO) sub-models were specially added .The combustion and emission characteristics of methanol HCCI engine were analyzed with the model .The results show that the reduced model agrees well with the detailed one in the aspects of heat release timing ,cumula-tive thermal effect ,in-cylinder temperature and pressure curve and has shorter calculation time ,which lays the foundation for improving the multi-dimension numerical simulation of chemical reaction flow .%采用敏感度分析法对二甲醚(CH3 OCH3)、甲醇(CH3 OH)详细机理进行简化,构建可用于均质压缩燃烧(HCCI)过程的二甲醚-甲醇简化动力学模型,包括38个物种和99个基元反应,特别添加了非常规排放物甲醛(CH2O)、甲酸(HCO2 H)和甲酸甲酯(CH3OCHO)的生成子模型。应用该简化机理模型对甲醇 HCCI发动机的燃烧与排放特性进行的算例分析表明,简化机理模型在燃烧放热特征时刻、燃烧累积热效应以及发动机缸内温度和压力曲线的预测值均与详细模型的计算值较为吻合,计算时间缩短,为提高化学反应流多维数值模拟的计算效率奠定了基础。

  12. Combustion characteristics of red alder bark. Technical progress report No. 6, September 16, 1977--Septermber 15, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Junge, D.C.

    1978-12-01

    Significant quantities of wood residue fuels are presently being used in industrial steam generating facilities. Recent studies indicate that substantial additional quantities of wood residue fuels are available for energy generation in the form of steam and/or electricity. A limited data base on the combustion characteristics of wood residue fuels has resulted in the installation and operation of inefficient combustion systems for these fuels. This investigation of the combustion characteristics of wood residue fuels was undertaken to provide a data base which could be used to optimize the combustion of such fuels. Optimization of the combustion process in industrial boilers serves to improve combustion efficiency and to reduce air pollutant emissions generated in he combustion process. Data are presented on the combustion characteristics of red alder bark.

  13. Mechanism of influence water vapor on combustion characteristics of propane-air mixture

    Science.gov (United States)

    Larionov, V. M.; Mitrofanov, G. A.; Sachovskii, A. V.; Kozar, N. K.

    2016-01-01

    The article discusses the results of an experimental study of the effect of water vapor at the flame temperature. Propane-butane mixture with air is burning on a modified Bunsen burner. Steam temperature was varied from 180 to 260 degrees. Combustion parameters changed by steam temperature and its proportion in the mixture with the fuel. The fuel-air mixture is burned in the excess air ratio of 0.1. It has been established that the injection of steam changes the characteristics of combustion fuel-air mixture and increase the combustion temperature. The concentration of CO in the combustion products is substantially reduced. Raising the temperature in the combustion zone is associated with increased enthalpy of the fuel by the added steam enthalpy. Reducing the concentration of CO is caused by decrease in the average temperature in the combustion zone by applying steam. Concentration of active hydrogen radicals and oxygen increases in the combustion zone. That has a positive effect on the process of combustion.

  14. Combustion Characteristics and Propulsive Performance of Boron/Ammonium Perchlorate Mixtures in Microtubes

    Science.gov (United States)

    Liang, Daolun; Liu, Jianzhong; Zhou, Junhu; Wang, Yang; Yang, Yuxin

    2016-07-01

    A microthruster is used for the operation tracking and posture control of microsatellites. In this work, the combustion characteristics and propulsive performance of a boron/ammonium perchlorate (B/AP) propellant mixture for a microthruster were investigated. Amorphous B and AP were used in different mass ratios to prepare the propellant samples. A laser-ignition solid micropropulsion test system was set up, and a differential scanning calorimeter was used. The solid combustion products of the samples with good performance were collected. Microstructural and component analyses of the combustion products were performed. Various performance parameters, including the combustion temperature, combustion velocity, spectral intensity, ignition delay time, thrust, specific impulse, density specific impulse, and heat flow, changed with the fuel-oxidant ratio. The optimal fuel-oxidant mass ratio of the propellant samples was 40%, with a density specific impulse of 0.474 kg/m2•s and a maximum heat flow of 4.4913 mW/mg. Analysis of the combustion products revealed that the clearance between particles significantly diminished after combustion. During combustion, the AP completely decomposed, and a large amount of H3BO3, B2O3, and HBO2 was generated.

  15. Combustion characteristics and influential factors of isooctane active-thermal atmosphere combustion assisted by two-stage reaction of n-heptane

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xingcai; Ji, Libin; Ma, Junjun; Zhou, Xiaoxin; Huang, Zhen [Key Lab. for Power Machinery and Engineering of MOE, Shanghai Jiao Tong University, 200240 Shanghai (China)

    2011-02-15

    This paper presents an experimental study on the isooctane active-thermal atmosphere combustion (ATAC) which is assisted by two-stage reaction of n-heptane. The active-thermal atmosphere is created by low- and high-temperature reactions of n-heptane which is injected at intake port, and isooctane is directly injected into combustion chamber near the top dead center. The effects of isooctane injection timing, active-thermal atmosphere intensity, overall equivalence ratio, and premixed ratio on combustion characteristics and emissions are investigated. The experimental results reveal that, the isooctane ignition and combustion can be classified to thermal atmosphere combustion, active atmosphere combustion, and active-thermal atmosphere combustion respectively according to the extent of n-heptane oxidation as well as effects of isooctane quenching and charge cooling. n-Heptane equivalence ratio, isooctane equivalence ratio and isooctane delivery advance angle are major control parameters. In one combustion cycle, the isooctane ignited and burned after those of n-heptane, and then this combustion phenomenon can also be named as dual-fuel sequential combustion (DFSC). The ignition timing of the overall combustion event is mainly determined by n-heptane equivalence ratio and can be controlled in flexibility by simultaneously adjusting isooctane equivalence ratio. The isooctane ignition regime, overall thermal efficiency, and NO{sub x} emissions show strong sensitivity to the fuel delivery advance angle between 20 CA BTDC and 25 CA BTDC. (author)

  16. A two conserved scalar model for HCCI and PPCI engine applications

    Science.gov (United States)

    Hamosfakidis, Vasileios

    There is a strong demand for a versatile computational model in the design of modern engines such as homogeneous charge compression ignition (HCCI) and partially premixed compression ignition (PPCI) engines. A robust model is required to describe accurately both the chemistry and turbulent mixing processes in the reacting flow. Although the existing computational fluid dynamics (CFD) codes coupled with detailed kinetics models may reproduce some realistic results, the excessive computational cost prevents them to be applicable as engineering tools. The present study aims at developing a new modeling approach that can describe the combustion process with high fidelity and computational efficiency. In this study, a two-conserved scalar approach is proposed to model HCCI and PPCI combustion. The first conserved scalar, the mixture fraction Z, is introduced to capture the inhomogeneities in the fuel-air mixture, and the second conserved scalar, the initial EGR fraction J, is introduced to capture the inhomogeneities in the fresh mixture-EGR charge. The main benefits of this approach are the reduction of dimensionality and the compactness of the domain in the conserved scalar plane, and the capability to use different resolutions for the chemistry and the fluid mechanics calculation. To solve the flow in the conserved scalar plane, two algorithms are proposed. First, the flamelet (zone) creation strategy is introduced to discretize the conserved scalar space based on its mass distribution and reactivity. The second part is the regeneration procedure which accounts for the nonlinear effect of EGR on reaction rates. Test results from the two-conserved scalar approach are compared to those obtained by direct calculation, and it is demonstrated that the regeneration process in the present approach can properly account for the nonlinear effects arising from chemical reactions, as an improvement over the representative interactive flamelet (RIF) approach. The two conserved

  17. Investigating pyrolysis and combustion characteristics of torrefied bamboo, torrefied wood and their blends.

    Science.gov (United States)

    Mi, Bingbing; Liu, Zhijia; Hu, Wanhe; Wei, Penglian; Jiang, Zehui; Fei, Benhua

    2016-06-01

    Bamboo and masson pine was torrefied with 300°C of temperature for 2.0h of residence time using GSL 1600X tube furnace in the argon atmosphere. Torrefied bamboo and masson pine particles were uniform mixed with different weight ratios. Pyrolysis and combustion characteristics were investigated through thermogravimetry (TGA). The results showed that pyrolysis and combustion process of all samples included three steps even though their characteristics were different. Torrefied biomass had a higher pyrolysis and combustion temperature, due to moisture and volatile removal and thermal decomposition of hemicelluloses, cellulose and lignin during torrefaction process. Torrefaction also increased high heating value, ash content and C/H and C/O ratio of biomass. The synergy of torrefied bamboo and torrefied mason pine was not found during pyrolysis and combustion process of blends. The results from this research will be very important and helpful to develop and utilize the wastes of masson pine and bamboo for energy products.

  18. Knock characteristics of dual-fuel combustion in diesel engines using natural gas as primary fuel

    Indian Academy of Sciences (India)

    O M I Nwafor

    2002-06-01

    This paper investigates the combustion knock characteristics of diesel engines running on natural gas using pilot injection as means of initiating combustion. The diesel engines knock under normal operating conditions but the knock referred to in this paper is an objectionable one. In the dual-fuel combustion process we have the ignition stage followed by the combustion stage. There are three types of knock: diesel knock, spark knock and knock due to secondary ignition delay of the primary fuel (erratic knock). Several factors have been noted to feature in defining knock characteristics of dual-fuel engines that include ignition delay, pilot quantity, engine load and speed, turbulence and gas flow rate.

  19. Combustion characteristics of coal and refuse from passenger trains.

    Science.gov (United States)

    Fu-min, Ren; Feng, Yue; Ming, Gao; Min, Yu

    2010-07-01

    Refuse from passenger trains is becoming a significant issue with the development of the Chinese railway. Co-firing is regarded as a promising thermal technology, both environmentally and economically, in reducing the quantity of refuse. The co-firing property of passenger train refuse with coal, however, may differ due to the differences in the composition of the refuse. In the present study, combustion properties of refuse from passenger train samples and the mixture of refuse with coal were studied in a tube furnace. Thermo analysis methods, such as thermogravimetry (TG), differential scanning calorimetry (DSC), differential thermal analysis (DTA) and derivative thermogravimetry (DTG) analyses were employed to evaluate combustion performance. We found that the mixture of passenger train refuse and coal at a ratio of 1:1 has a lower ignition and burnout temperature than the coal-only sample. Moreover, refuse from railway passenger trains has more reactive combustion properties than the coal-only sample, and the addition of railway passenger train refuse to coal can promote the reactivity of coal.

  20. Formation mechanism of bimetal composite layer between LCS and HCCI

    Directory of Open Access Journals (Sweden)

    Yong-chang Zhu

    2016-11-01

    Full Text Available A low carbon steel (LCS/high chromium white cast iron (HCCI bimetal wear plate about 20 mm in thickness was prepared by liquid-liquid bimetal composite casting technology to substitute for the welding wear plate. A clear and distinguishable composite layer between the LCS and the HCCI was detected with SEM, and the composition and phase were analyzed through EDS and XRD. The composite layer was composed of three sublayers from the LCS to the HCCI: pearlite transition layer, composite layer, and HCCI transition layer. The Vickers hardness from the pearlite transition layer to the HCCI transition layer was 360 HV to 855 HV. The austenite grows as dendrites between the composite layer and the HCCI transition layer under constitutional undercooling. A large amount of C and Cr, and a small amount of Si and Mn dissolve in the matrix. Granular Cr7C3 is uniformly distributed. Due to the solute redistribution at the solid-liquid interface, the primary austenite grows from planar to cellular and finally to the distinct dendrite crystals. The dendrite crystals have an obvious growth direction perpendicular to the composite layer.

  1. Miniature Internal Combustion Engine-Generator for High Energy Density Portable Power

    Science.gov (United States)

    2008-12-01

    very effective at maintaining a constant voltage and stroke as the HCCI combustion pressure varies during engine warmup. The current is modulated by the...Comparison of Measured and Predicted Two- Stroke Engine Power Output for Jet-A and Propane 5 The exhaust emissions of the 300 W MICE generator with HCCI ...1 Two-Stroke Engine Double- Helix Spring Linear Alternator Magnet Pole Permanent Magnet Alternator Coil Spring Casing Coil Standoff Double-Helix

  2. Development of High Efficiency Clean Combustion Engine Designs for Spark-Ignition and Compression-Ignition Internal Combustion Engines

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, Craig; Gonzalez, Manual; Russell, Durrett

    2011-06-30

    This report summarizes activities related to the revised STATEMENT OF PROJECT OBJECTIVES (SOPO) dated June 2010 for the Development of High-Efficiency Clean Combustion engine Designs for Spark-Ignition and Compression-Ignition Internal Combustion Engines (COOPERATIVE AGREEMENT NUMBER DE-FC26-05NT42415) project. In both the spark- (SI) and compression-ignition (CI) development activities covered in this program, the goal was to develop potential production-viable internal combustion engine system technologies that both reduce fuel consumption and simultaneously met exhaust emission targets. To be production-viable, engine technologies were also evaluated to determine if they would meet customer expectations of refinement in terms of noise, vibration, performance, driveability, etc. in addition to having an attractive business case and value. Prior to this activity, only proprietary theoretical / laboratory knowledge existed on the combustion technologies explored The research reported here expands and develops this knowledge to determine series-production viability. Significant SI and CI engine development occurred during this program within General Motors, LLC over more than five years. In the SI program, several engines were designed and developed that used both a relatively simple multi-lift valve train system and a Fully Flexible Valve Actuation (FFVA) system to enable a Homogeneous Charge Compression Ignition (HCCI) combustion process. Many technical challenges, which were unknown at the start of this program, were identified and systematically resolved through analysis, test and development. This report documents the challenges and solutions for each SOPO deliverable. As a result of the project activities, the production viability of the developed clean combustion technologies has been determined. At this time, HCCI combustion for SI engines is not considered production-viable for several reasons. HCCI combustion is excessively sensitive to control variables

  3. Combustion characteristics of Douglas Fir planer shavings. Technical progress report No. 4, September 16, 1977--September 15, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Junge, D.C.

    1978-12-01

    Significant quantities of wood residue fuels are presently being used in industrial steam generating facilities. Recent studies indicate that substantial additional quantities of wood residue fuels are available for energy generation in the form of steam and/or electricity. A limited data base on the combustion characteristics of wood residue fuels has resulted in the installation and operation of inefficient combustion systems for these fuels. This investigation of the combustion characteristics of wood residue fuels was undertaken to provide a data base which could be used to optimize the combustion of such fuels. Optimization of the the combustion process in industrial boilers serves to improve combustion efficiency and to reduce air pollutant emissions generated in the combustion process. This report presents data on the combustion characteristics of Douglas Fir planer shavings. The data were obtained in a pilot scale combustion test facility at Oregon State Univerisity. Other technical reports present data on the combustion characteristics of: Douglas Fir bark, Red Alder sawdust, Red Alder bark, Ponderosa pine bark, Hemlock bark, and Eastern White Pine bark. An executive summary report is also available which compares the combustion characteristics of the various fuel species.

  4. Large Eddy Simulation of Turbulent Combustion

    Science.gov (United States)

    2006-03-15

    Application to an HCCI Engine . Proceedings of the 4th Joint Meeting of the U.S. Sections of the Combustion Institute, 2005. [34] K. Fieweger...LARGE EDDY SIMULATION OF TURBULENT COMBUSTION Principle Investigator: Heinz Pitsch Flow Physics and Computation Department of Mechanical Engineering ...burners and engines found in modern, industrially relevant equipment. In the course of this transition of LES from a scientifically interesting method

  5. Study of combustion and emission characteristics of turbocharged diesel engine fuelled with dimethylether

    Institute of Scientific and Technical Information of China (English)

    Junhua WU; Zhen HUANG; Xinqi QIAO; Jun LU; Junjun ZHANG; Liang ZHANG

    2008-01-01

    An experimental study of a turbocharged diesel engine operating on dimethyl ether (DME) was conducted. The combustion and emission characteristics of the DME engine were investigated. The results show that the maximum torque and power of DME are greater than those of diesel, particularly at low speeds; the brake specific fuel consum-ption of DME is lower than that of diesel at low and middle engine speeds, and the injection delay of DME is longer than that of diesel. However, the maximum cylinder pressure, maximum pressure rise rate and combustion noises of the DME engine are lower than those of diesel. The combustion velocity of DME is faster than that of diesel, resulting in a shorter combustion duration of DME. Compared with the diesel engine, NOx emission of the DME engine is reduced by 41.6% on ESC data. In addition, the DME engine is smoke free at any operating condition.

  6. Combustion characteristics of Daqing oil shale and oil shale semi-cokes

    Institute of Scientific and Technical Information of China (English)

    MIAO Zhen-yong; WU Guo-guang; LI Ping; ZHAO Na; WANG Pan-cheng; MENG Xian-liang

    2009-01-01

    Thermo-gravimetric-analysis (TGA) was used to analyze the combustion characteristics of an oil shale and semi-cokes prepared from it. The effect of prior pyrolysis and TGA heating rate on the combustion process was studied. Prior pyrolysis affects the initial temperature of mass loss and the ignition temperature. The ignition temperature increases as the volatile content of the sample decreases. TG/DTG curves obtained at different heating rates show that heating rate has little effect on ignition temperature. But the peak of combustion shifts to higher temperatures as the heating rate is increased. The Coats-Redfern integration method was employed to find the combustion-reaction kinetic parameters for the burning of oil shale and oil shale semi-coke.

  7. Emission and combustion characteristics of multiple stage diesel combustion; Nidan nensho ni yoru diesel kikan no nensho to haishutsubutsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Hashizume, T.; Miyamoto, T.; Tsujimura, K. [New A.C.E. Institute Co. Ltd., Tokyo (Japan); Kobayashi, S.; Shimizu, K. [Japan Automobile Research Institute, Tsukuba (Japan)

    1997-10-01

    A new concept of multiple stage diesel combustion was studied by means of engine test, combustion observation and numerical simulation, in order to reduce NOx emissions at high load conditions. With this concept, the premixed combustion occurs under the fuel lean conditions and the diffusion combustion occurs under the high temperature conditions. As seen in the result of combustion observation, a first stage combustion occurs with no luminous flame. A second stage combustion occurs with a luminous flame after very short ignition delay period. However the luminous flame is disappeared immediately. Because cylinder temperature is high, and hence soot oxidizes immediately. 5 refs., 11 figs., 1 tab.

  8. Homogeneous Charge Compression Ignition Combustion of Dimethyl Ether

    DEFF Research Database (Denmark)

    Pedersen, Troels Dyhr

    mechanism greatly reduces both. Reaction paths for methanol and methane were included amongst the elementary reactions, since these two fuels are commonly used to control the radical behavior in the initial phase of combustion and hence the combustion phasing of the fuel in an engine, as well as enabling...... an increase in engine power. The use of methanol for combustion phasing control was tested successfully in a large diesel engine with common rail, in which the piston bowls were widened to give a compression ratio of 14.5. This compression ratio still allows DI CI operation with DME, but requires...... a substantial combustion delay in HCCI operation with DME to achieve post TDC combustion. By adding methanol to the inlet port during HCCI combustion of DME, the engine reached 50 percent of its full DI CI load capability without engine knock at 1000 rpm and somewhat less at 1800 rpm. The engine also had EGR...

  9. Frozen Characteristics of NO_x and Their Related Compositions in Combustion Gas

    Institute of Scientific and Technical Information of China (English)

    苏适; 蔡崧; 徐益谦

    1994-01-01

    In order to study the produce and reduce characteristics of the NOx in the process of fuel combustion and combustion gas denitrogenation, the frozen characteristics of the NOx and their related components of uniform gases at high temperature of 1400 - 2600 K in a quenching rate of 0.2×108 -0.4×108 K/s are studied. The effects of cooling rate on the results of analysis of NO and NO2 in gases sampled by sampling probe are discussed. The mathematical models and chemical kinetic models which express the relaxation process of gas compositions in nonequilibrium condition of quenching process are constructed.

  10. Emission characteristics and combustion instabilities in an oxy-fuel swirl-stabilized combustor

    Institute of Scientific and Technical Information of China (English)

    Guo-neng LI; Hao ZHOU; Ke-fa CEN

    2008-01-01

    This paper presents an experimental study on the emission characteristics and combustion instabilities of oxy-fuel combustions in a swirl-stabilized combustor.Different oxygen concentrations(Xoxy=25%-45%,where Xoxy is oxygen concentra-tion by volume),equivalence ratios(=0.75~1.15)and combustion powers(CP=1.08~2.02kW)were investigated in the oxy-fuel (CH4/CO2/O2)combustions,and reference cases(Xoxy=25%~35%,Cha/N2/O2 flames)were covered.The results show that the oxygen concentration in the oxidant stream significantly affects the combustion delay in the oxy-fuel flames,and the equivalence ratio has a slight effect,whereas the combustion power shows no impact.The temperature levels of the oxy-fuel flames inside the combustion chamber are much higher(up to 38.7%)than those of the reference cases.Carbon monoxide was vastly producedwhen Xoxy>35% or >0.95 in the oxy-fuel flames,while no nitric oxide was found in the exhaust gases because no N2 participates in the combustion process.The combustion instability of the oxy-fuel combustion is very different from those of the reference cases with similar oxygen content.Oxy-fuel combustions excite strong oscillations in all cases studied Xoxy=25%~45%.However,no pressure fluctuations were detected in the reference cases when Xoxy>28.6% accomplished by heavily sooting flames which were not found in the oxy-fuel combustions.Spectrum analysis shows that the frequency of dynamic pressure oscillations exhibits randomness in the range of 50~250 Hz,therefore resulting in a very small resultant amplitude.Temporal oscillations are very strong with amplitudes larger than 200 Pa,even short time fast Fourier transform(FFT)analysis(0.08 s)shows that the pressure amplitude can be larger than 40 Pa.

  11. Combustion characteristics of the LO2/GCH4 fuel-rich preburners for staged combustion cycle rocket engines

    Science.gov (United States)

    Ono, Fumiei; Tamura, Hiroshi; Sakamoto, Hiroshi; Sasaki, Masaki

    1991-09-01

    The combustion characteristics of Liquid Oxygen (LO2)/Gaseous Methane (GCH4) fuel rich preburners were experimentally studied using subscale hardware. Three types of preburners with coaxial type propellant injection elements were designed and fabricated, and were used for hot fire testing. LO2 was used as oxidizer, and GCH4 at room temperature was used as fuel. The tests were conducted at chamber pressures ranging from 6.7 to 11.9 M Pa, and oxidizer to fuel ratios ranged from 0.16 to 0.42. The test results, which include combustion gas temperature T(sub c), characteristic velocity C(sup *) and soot adhesion data, are presented. The T(sub c) efficiency and the C(sup *) efficiency were found to be a function of oxidizer to fuel ratio and chamber pressure. These efficiencies are correlated by an empirical correlation parameter which accounts for the effects of oxidizer to fuel ratio and chamber pressure. The exhaust plumes were colorless and transparent under all tests conditions. There was some soot adhesion to the chamber wall, but no soot adhesion was observed on the main injector simulator orifices. Higher temperature igniter gas was required to ignite the main propellants of the preburner compared with that of the LO2/Gaseous Hydrogen (GH2) propellants combination.

  12. Control of homogeneous charge compression ignition combustion in a two-cylinder gasoline direct injection engine with negative valve overlap

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi; WANG Jianxin; SHUAI Shijin; MA Qingjun; TIAN Guohong

    2007-01-01

    Homogeneous charge compression ignition(HCCI) has challenges in ignition timing control,combustion rate control,and operating range extension.In this paper,HCCI combustion was studied in a two-cylinder gasoline direct injection (GDI) engine with negative valve overlap (NVO).A two-stage gasoline direct injection strategy combined with negative valve overlap was used to control mixture formation and combustion.The gasoline engine could be operated in HCCI combustion mode at a speed range of 800-2 200 r/min and load,indicated mean effective pressure (IMEP) range of 0.1-0.53 MPa.The engine fuel consumption 4× 10-5 without soot emission.The effect of different injection strategies on HCCI combustion was studied.The experimental results indicated that the coefficient of variation of the engine cycle decreased by using NVO with two-stage direct injection;the ignition timing and combustion rate could be controlled;and the operational range of HCCI combustion could be extended.

  13. Numerical modeling on homogeneous charge compression ignition combustion engine fueled by diesel-ethanol blends

    Directory of Open Access Journals (Sweden)

    Hanafi H.

    2016-01-01

    Full Text Available This paper investigates the performance and emission characteristics of HCCI engines fueled with oxygenated fuels (ethanol blend. A modeling study was conducted to investigate the impact of ethanol addition on the performance, combustion and emission characteristics of a Homogeneous Charge Compression Ignition (HCCI engine fueled by diesel. One dimensional simulation was conducted using the renowned commercial software for diesel and its blend fuels with 5% (E5 and 10% ethanol (E10 (in vol. under full load condition at variable engine speed ranging from 1000 to 2750 rpm with 250 rpm increment. The model was then validated with other researcher’s experimental result. Model consists of intake and exhaust systems, cylinder, head, valves and port geometries. Performance tests were conducted for volumetric efficiency, brake engine torque, brake power, brake mean effective pressure, brake specific fuel consumption, and brake thermal efficiency, while exhaust emissions were analyzed for carbon monoxide (CO and unburned hydrocarbons (HC. The results showed that blending diesel with ethanol increases the volumetric efficiency, brake specific fuel consumption and brake thermal efficiency, while it decreases brake engine torque, brake power and brake mean effective pressure. In term of emission characteristics, the CO emissions concentrations in the engine exhaust decrease significantly with ethanol as additive. But for HC emission, its concentration increase when apply in high engine speed. In conclusion, using Ethanol as fuel additive blend with Diesel operating in HCCI shows a good result in term of performance and emission in low speed but not recommended to use in high speed engine. Ethanol-diesel blends need to researched more to make it commercially useable.

  14. INFLUENCE OF SWIRL ON SPRAY CHARACTERISTICS AND COMBUSTION, A NUMERICAL INVESTIGATION OF A CATERPILLER DIESEL ENGINE

    Directory of Open Access Journals (Sweden)

    M. SREENIVASULU

    2012-10-01

    Full Text Available The purpose of this study is to find the appropriate swirl ratio at which a DI diesel engine should be operated. In the process of identifying an appropriate swirl, the combustion behaviour was analysed by considering Pressure variations and Heat Release Rate variations against crank angle. The spray characteristics were also analysed by considering Penetration lengths, Sauter mean diameters, Spray cone angles against crank angle. Final conclusions were derived by considering NOx emission levels. A turbo charged DI diesel engine geometry was considered for the analysis. Proper care was taken inidentifying the range of Swirl Ratios. A 3-dimensional CFD code (RECARDO VECTIS, which is capable of solving 3-dimensional unsteady, turbulent flows, sprays and combustion of IC engines was used. In the first step CFD code was validated by comparing the obtained results with the experimental results. In the next step an attempt was made to study the influence of swirl on the spray characteristics and combustion.

  15. Combustion characteristics of Athabasca froth treatment tailings in a simulated fluidilized bed

    Energy Technology Data Exchange (ETDEWEB)

    Esmaeili, P.; Ghosh, M.; Speirs, B. C. [Imperial Oil Resources (Canada); Leon, M. A.; Rao, S.; Dutta, A.; Basu, P. [Greenfield Research Inc. (Canada)

    2011-07-01

    In surface-mined oil sands, a stream of water, asphaltenes, solids and residual bitumen/solvent, known as PFT tailings, is created during the bitumen production process. The aim of this study was to investigate the use of this PFT tailings stream as a fuel source for combustion in a fluidized bed for energy recovery. To do so, physical and fluidization characteristics of the fuel as well as combustion kinetics were assessed through laboratory analysis. In addition, the fuel's combustion characteristics were investigated through experiments in a quartz wool matrix tubular reactor and theoretical calculations at various moisture contents. Results showed that this fuel can be burned in a fluidized bed with a reactivity comparable to that of coal samples. This research found that PFT tailings could be used to generate energy during disposal but further work will have to be undertaken in a hot CFB combustor to confirm this.

  16. Combustion stability characteristics of the model chamber with various configurations of triplet impinging-jet injectors

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Chae Hoon [Chosun University, Gwangju (Korea, Republic of); Seol, Woo Seok [Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Shibanov, Alexander A. [Research Institute of Chemical Machine Building, Sergiev Posad (Russian Federation)

    2006-06-15

    Combustion stability characteristics in actual full-scale combustion chamber of a rocket engine are investigated by experimental tests with the model (sub-scale) chamber. The present hot-fire tests adopt the combustion chamber with three configurations of triplet impinging-jet injectors such as F-O-O-F, F-O-F, and O-F-O configurations. Combustion stability boundaries are obtained and presented by the parameters of combustion-chamber pressure and mixture (oxidizer/fuel) ratio. From the experimental tests, two instability regions are observed and the pressure oscillations have the similar patterns irrespective of injector configuration. But, the O-F-O injector configuration shows broader upper-instability region than the other configurations. To verify the instability mechanism for the lower and upper instability regions, air-purge acoustic test is conducted and the photograph of the flames is taken. As a result, it is found that the pressure oscillations in the two regions can be characterized by the first impinging point of hydraulic jets and pre-blowout combustion, respectively.

  17. Combustion Characteristics of Butane Porous Burner for Thermoelectric Power Generation

    Directory of Open Access Journals (Sweden)

    K. F. Mustafa

    2015-01-01

    Full Text Available The present study explores the utilization of a porous burner for thermoelectric power generation. The porous burner was tested with butane gas using two sets of configurations: single layer porcelain and a stacked-up double layer alumina and porcelain. Six PbSnTe thermoelectric (TE modules with a total area of 54 cm2 were attached to the wall of the burner. Fins were also added to the cold side of the TE modules. Fuel-air equivalence ratio was varied between the blowoff and flashback limit and the corresponding temperature, current-voltage, and emissions were recorded. The stacked-up double layer negatively affected the combustion efficiency at an equivalence ratio of 0.20 to 0.42, but single layer porcelain shows diminishing trend in the equivalence ratio of 0.60 to 0.90. The surface temperature of a stacked-up porous media is considerably higher than the single layer. Carbon monoxide emission is independent for both porous media configurations, but moderate reduction was recorded for single layer porcelain at lean fuel-air equivalence ratio. Nitrogen oxides is insensitive in the lean fuel-air equivalence ratio for both configurations, even though slight reduction was observed in the rich region for single layer porcelain. Power output was found to be highly dependent on the temperature gradient.

  18. Optimization of a Reduced Chemical Kinetic Model for HCCI Engine Simulations by Micro-Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A reduced chemical kinetic model (44 species and 72 reactions) for the homogeneous charge compression ignition (HCCI) combustion of n-heptane was optimized to improve its autoignition predictions under different engine operating conditions. The seven kinetic parameters of the optimized model were determined by using the combination of a micro-genetic algorithm optimization methodology and the SENKIN program of CHEMKIN chemical kinetics software package. The optimization was performed within the range of equivalence ratios 0.2-1.2, initial temperature 310-375 K and initial pressure 0.1-0.3 MPa. The engine simulations show that the optimized model agrees better with the detailed chemical kinetic model (544 species and 2 446 reactions) than the original model does.

  19. Experimental and Modeling Studies of the Characteristics of Liquid Biofuels for Enhanced Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Meeks, E.; Modak, A. U.; Naik, C. V.; Puduppakkam, K. V.; Westbrook, C.; Egolfopoulos, F. N.; Tsotsis, T.; Roby, S. H.

    2009-07-01

    The objectives of this project have been to develop a comprehensive set of fundamental data regarding the combustion behavior of biodiesel fuels and appropriately associated model fuels that may represent biodiesels in automotive engineering simulation. Based on the fundamental study results, an auxiliary objective was to identify differentiating characteristics of molecular fuel components that can be used to explain different fuel behavior and that may ultimately be used in the planning and design of optimal fuel-production processes. The fuels studied in this project were BQ-9000 certified biodiesel fuels that are certified for use in automotive engine applications. Prior to this project, there were no systematic experimental flame data available for such fuels. One of the key goals has been to generate such data, and to use this data in developing and verifying effective kinetic models. The models have then been reduced through automated means to enable multi-dimensional simulation of the combustion characteristics of such fuels in reciprocating engines. Such reliable kinetics models, validated against fundamental data derived from laminar flames using idealized flow models, are key to the development and design of optimal engines, engine operation and fuels. The models provide direct information about the relative contribution of different molecular constituents to the fuel performance and can be used to assess both combustion and emissions characteristics. During this project, we completed a major and thorough validation of a set of biodiesel surrogate components, allowing us to begin to evaluate the fundamental combustion characteristics for B100 fuels.

  20. Experimental and Modeling Studies of the Characteristics of Liquid Biofuels for Enhanced Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Meeks, E.; Modak, A. U.; Naik, C. V.; Puduppakkam, K. V.; Westbrook, C.; Egolfopoulos, F. N.; Tsotsis, T.; Roby, S. H.

    2009-07-01

    The objectives of this project have been to develop a comprehensive set of fundamental data regarding the combustion behavior of biodiesel fuels and appropriately associated model fuels that may represent biodiesels in automotive engineering simulation. Based on the fundamental study results, an auxiliary objective was to identify differentiating characteristics of molecular fuel components that can be used to explain different fuel behavior and that may ultimately be used in the planning and design of optimal fuel-production processes. The fuels studied in this project were BQ-9000 certified biodiesel fuels that are certified for use in automotive engine applications. Prior to this project, there were no systematic experimental flame data available for such fuels. One of the key goals has been to generate such data, and to use this data in developing and verifying effective kinetic models. The models have then been reduced through automated means to enable multi-dimensional simulation of the combustion characteristics of such fuels in reciprocating engines. Such reliable kinetics models, validated against fundamental data derived from laminar flames using idealized flow models, are key to the development and design of optimal engines, engine operation and fuels. The models provide direct information about the relative contribution of different molecular constituents to the fuel performance and can be used to assess both combustion and emissions characteristics. During this project, we completed a major and thorough validation of a set of biodiesel surrogate components, allowing us to begin to evaluate the fundamental combustion characteristics for B100 fuels.

  1. In-Situ Characteristics of Particle Emissions from Biomass Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Pagels, Joakum; Wierzbicka, Aneta; Bohgard, Mats [Lund Univ. (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Bioenergy Technology; Swietlicki, Erik [Lund Univ. (Sweden). Div. of Nuclear Physics

    2005-07-01

    In this work we used a Scanning Mobility Particle Sizer and an Electrical Low-pressure Impactor to: a) Derive information of the particle morphology through air-borne analysis and b) Identify time and size variations of particle phase components from incomplete combustion and ash-components. The results presented here covers measurements in two moving grate boilers (12 MW operating on moist forest residue and 1.5 MW operating on wood pellets). We have previously shown that PM1 estimated from Electrical Low-Pressure Impactor (ELPI)-measurements consisted of a rather constant background with peaks correlating with CO and OGC peaks. In the 1.5 MW boiler EC contributed to 34% of PM1, while in the 12 MW boiler EC was below 0.5%. Figure 2 shows time variations in the 1.5 MW boiler as the current in three stages of the ELPI-impactor. Note that time-variations increase strongly with particle size. The fraction of the gravimetric mass detected as water-soluble ions (IC) decreased from {approx} 70% for dae= 78 and 133 nm to {approx} 25% for 322 and 510 nm particles and increased to around 50% for particles larger than 1 {mu}m. In the 12 MW boiler time variations were as low as for 128 nm particles and IC recovery was high for all studied particle sizes. Based on these data we conclude that PM consisting of ash-components are formed with small time variations mainly in mobility-sizes below 250 nm, while Elemental Carbon is emitted at high concentrations during peaks on the time-scale 10-30 s, mainly in particle sizes larger than 150 nm. However, the detailed mixing status of these two particle types/materials is still not known.

  2. Experimental Research on Mode Switch in a Multi-Cylinder HCCI Engine%多缸HCCI汽油机SIAI/AI燃烧模式切换的试验

    Institute of Scientific and Technical Information of China (English)

    李东升; 张志福; 杨万里; 阳冬波; 王志; 王建昕

    2012-01-01

    HCCI/SI composited combustion model is regarded as a practical operation strategy for gasoline HCCI engines.But different demand of air-fuel ratio and internal EGR rate bring the control difficultly in HCCI/SI mode switch.Switch frequency HCCI engine Combustion mode is high due to the narrow load range,and this reduces the operation stability.Based on multi-cylinder gasoline engine with a two-stage CAM profile,the spark-induced auto-ignition(SIAI)was realized,and SIAI/SI combustion mode switch was studied.Results showed that fuel injection at compression stroke combined with spark-ignition strategy can effectively avoid misfire,improve stability of mode switch.SIAI can extend the load operation range of HCCI combustion,and effectively reduce mode switch frequency.%HCCI/SI复合燃烧模式是HCCI汽油发动机实用化的运行策略.但不同的空燃比和内部EGR率的需求给HCCI/SI模式切换带来了极大控制难度;同时由于HCCI负荷范围窄,使得燃烧模式切换频率过高,降低了发动机运行稳定性.在一台具备错位双凸轮机构的多缸汽油机上实现了火花点火激发混合气自燃着火(SIAI)燃烧方式,扩展了压燃模式下的负荷范围,研究了SIAI/SI燃烧模式的切换.结果表明,采用压缩冲程燃油喷射配合火花点火策略能够有效地避免燃烧模式切换中的失火现象,提高模式切换的稳定性;同时采用SIAI燃烧方式扩展内部EGR条件下的负荷范围,可以有效地减小模式切换频率.

  3. Prediction of the Resonance Characteristics of Combustion Chambers on the Basis of Large-Eddy Simulation

    Institute of Scientific and Technical Information of China (English)

    Franco MAGAGNATO; Bal(a)zs PRITZ; Horst B(U)CHNER; Martin GABI

    2005-01-01

    @@ In the last few years intensive experimental investigations were performed at the University of Karlsruhe to develop an analytical model for the Helmholtz resonator-type combustion system. In the present work the resonance characteristics of a Helmholtz resonator-type combustion chamber were investigated using large-eddy simulations (LES), to understand better the flow effects in the chamber and to localize the dissipation. In this paper the results of the LES are presented, which show good agreement with the experiments. The comparison of the LES study with the experiments sheds light on the significant role of the wall roughness in the exhaust gas pipe.

  4. Numerical study on combustion characteristics of nitrogen diluted hydrogen-rich syngas at high pressures

    Institute of Scientific and Technical Information of China (English)

    FU Zhongguang∗; LU Ke; ZHOU Yang; ZHU Yiming; LIU Xueqi

    2014-01-01

    Aiming at investigating the micro-mixing combustion characteristics of nitrogen diluted hydrogen-rich syngas at high pressures,the combustion model corrected at atmospheric pressure was adopted to ana-lyze the temperature field,flame shape and pollution emissions under conditions with different pressures, powers and equivalent ratios.The results show that,with an increase in pressure,the flame temperature and outlet temperature of the burner rose first and then dropped slightly;the flame width decreased gradu-ally while its height grew;the NOx emission indexes increased and tended to be smooth when the pressure increased to higher than 1 4 MPa.

  5. Research on EHN additive on the diesel engine combustion characteristics in plateau environment

    Science.gov (United States)

    Sun, Zhixin; Li, Ruoting; Wang, Xiancheng; Hu, Chuan

    2017-03-01

    Aiming at the combustion deterioration problem of diesel engine in plateau environment, a bench test was carried out for the effects of EHN additive on combustion characteristics of the diesel engine with intake pressure of 0.68 kPa. Test results showed that with the full load working condition of 1 400 r/min: Cylinder pressure and pressure uprising rate decreased with EHN additive added in, mechanical load on the engine could be relieved; peak value of the heat release rate decreased and its occurrence advanced, ignition delay and combustion duration were shortened; cylinder temperature and exhaust gas temperature declined, thermal load on the engine could be relieved, output torque increased while specific oil consumption decreased, and effective thermal efficiency of diesel engine increased.

  6. Combustion characteristics of SI engine fueled with methanol-gasoline blends during cold start

    Institute of Scientific and Technical Information of China (English)

    Ruizhi SONG; Tiegang HU; Shenghua LIU; Xiaoqiang LIANG

    2008-01-01

    A 3-cylinder port fuel injection (PFI) engine fueled with methanol-gasoline blends was used to study combustion and emission characteristics. Cylinder pres-sure analysis indicates that engine combustion is improved when methanol is added to gasoline. With the increase of methanol, the flame developing period and the rapid combustion period are shortened, and the indicated mean effective pressure increases during the first 50 cycles. Meanwhile, a novel quasi-instantaneous sampling system was designed to measure engine emissions during cold start and warm-up. The results at 5℃ show that unburned hydrocarbon (UHC) and carbon monoxide (CO) decrease remarkably. Hydrocarbon (HC) reduces by 40% and CO by 70% when fueled with M30 (30% methanol in volume). The exhaust gas temperature is about 140℃ higher at 200 s after operation compared with that of gasoline.

  7. Development and Validation of a Reduced DME Mechanism Applicable to Various Combustion Modes in Internal Combustion Engines

    Directory of Open Access Journals (Sweden)

    Gregory T. Chin

    2011-01-01

    Full Text Available A 28-species reduced chemistry mechanism for Dimethyl Ether (DME combustion is developed on the basis of a recent detailed mechanism by Zhao et al. (2008. The construction of reduced chemistry was carried out with automatic algorithms incorporating newly developed strategies. The performance of the reduced mechanism is assessed over a wide range of combustion conditions anticipated to occur in future advanced piston internal combustion engines, such as HCCI, SAHCCI, and PCCI. Overall, the reduced chemistry gives results in good agreement with those from the detailed mechanism for all the combustion modes tested. While the detailed mechanism by Zhao et al. (2008 shows reasonable agreement with the shock tube autoignition delay data, the detailed mechanism requires further improvement in order to better predict HCCI combustion under engine conditions.

  8. Effect of Nitrate Ester on the Combustion Characteristics of PET/HMX -based Propellants

    Directory of Open Access Journals (Sweden)

    Yunlan Sun

    2011-04-01

    Full Text Available The effect of nitrate ester NG/TEGDN on the combustion characteristics of PET/HMX-based propellants has been experimentally investigated using of high-speed photography technique and scanning electron microscopy. It is indicated that the increase of NG/TEGDN content has little impact on the propellant burning rates at the same pressure. Furthermore, propellant can not be self-sustaining combustion at low pressure (£1 MPa. The increase of NG/TEGDN content does not affect the flame structure of propellant, but it plays an important role in condensed phase reaction zone. The flame structure of propellant is estimated. The thermal decomposition products in different combustion zones are also discussed. Scanning electron microscopy examination of quenched sample indicates that a liquified layer forms during combustion of these propellants. Numerous gas bubbles are present. Especially, the burning surface of propellant with low NG/TEGDN content shows signs of crystallization. The thickness of condensed phase reaction zone, by cross-section examination of propellant burning surface, has also been investigated. The results show that the thickness of condensed phase reaction zone increases with NG/TEGDN content increasing. These observations suggest that the condensed phase zone plays significant role in propellant combustion.Defence Science Journal, 2011, 61(3, pp.206-213, DOI:http://dx.doi.org/10.14429/dsj.61.567

  9. The effect of nitrogen on biogas flame propagation characteristic in premix combustion

    Science.gov (United States)

    Anggono, Willyanto; Suprianto, Fandi D.; Hartanto, Tan Ivan; Purnomo, Kenny; Wijaya, Tubagus P.

    2016-03-01

    Biogas is one of alternative energy and categorized as renewable energy. The main sources of biogas come from animal waste, garbage, and household waste that are organic waste. Primarily, over 50% of this energy contains methane (CH4). The other substances or inhibitors are nitrogen and carbon dioxide. Previously, carbon dioxide effect on biogas combustion is already experimented. The result shows that carbon dioxide reduces the flame propagation speed of biogas combustion. Then, nitrogen as an inhibitor obviously also brings some effects to the biogas combustion, flame propagation speed, and flame characteristics. Spark ignited cylinder is used for the premixed biogas combustion research. An acrylic glass is used as the material of this transparent cylinder chamber. The cylinder is filled with methane (CH4), oxygen (O2), and nitrogen (N2) with particular percentage. In this experiment, the nitrogen composition are set to 0%, 5%, 10%, 20%, 30%, 40%, and 50%. The result shows that the flame propagation speed is reduced in regard to the increased level of nitrogen. It can also be implied that nitrogen can decrease the biogas combustion rate.

  10. High-Speed Visualisation of Combustion in Modern Gasoline Engines

    Science.gov (United States)

    Sauter, W.; Nauwerck, A.; Han, K.-M.; Pfeil, J.; Velji, A.; Spicher, U.

    2006-07-01

    Today research and development in the field of gasoline engines have to face a double challenge: on the one hand, fuel consumption has to be reduced, while on the other hand, ever more stringent emission standards have to be fulfilled. The development of engines with its complexity of in-cylinder processes requires modern development tools to exploit the full potential in order to reduce fuel consumption. Especially optical, non-intrusive measurement techniques will help to get a better understanding of the processes. With the presented high-speed visualisation system the electromagnetic radiation from combustion in the UV range is collected by an endoscope and transmitted to a visualisation system by 10, 000 optical fibres. The signal is projected to 1, 920 photomultipliers, which convert the optical into electric signals with a maximum temporal resolution of 200 kHz. This paper shows the systematic application of flame diagnostics in modern combustion systems. For this purpose, a single-cylinder SI engine has been modified for a spray guided combustion strategy as well as for HCCI. The characteristics of flame propagation in both combustion modes were recorded and correlated with thermodynamic analyses. In case of the spray guided GDI engine, high pressure fuel injection was applied and evaluated.

  11. Impact of the Flameholder Heat Conductivity on Combustion Instability Characteristics

    KAUST Repository

    Hong, Seunghyuck

    2012-06-11

    In this paper, we investigate the impact of heat transfer between the flame and the flame-holder on the dynamic stability characteristics in a 50-kW backward facing step combustor. We conducted tests where we use a backward step block made of two different materials: ceramic and stainless steel whose thermal conductivities are 1.06 and 12 W/m/K, respectively. A set of experiments was conducted using a propane/air mixture at Re = 6500 for the inlet temperature of 300 - 500 K at atmospheric pressure. We measure the dynamic pressure and flame chemiluminescence to examine distinct stability characteristics using each flame-holder material over a range of operating conditions. We find that for tests with a flame-holder made of ceramic, the onset of instability is significantly delayed in time and, for certain operating conditions, disappears altogether. Stated differently, for certain operating conditions, the combustor can be stabilized by reducing the thermal conductivity of the flame-holder. As the thermal conductivity of the flame-holder increases, the combustor becomes increasingly unstable over a range of operating conditions. These results imply that the dynamic stability characteristics depend strongly on the heat transfer between the flame and the combustor wall near the flame anchoring region. Copyright © 2012 by ASME.

  12. Intermediate temperature heat release in an HCCI engine fueled by ethanol/n-heptane mixtures: An experimental and modeling study

    KAUST Repository

    Vuilleumier, David

    2014-03-01

    This study examines intermediate temperature heat release (ITHR) in homogeneous charge compression ignition (HCCI) engines using blends of ethanol and n-heptane. Experiments were performed over the range of 0-50% n-heptane liquid volume fractions, at equivalence ratios 0.4 and 0.5, and intake pressures from 1.4bar to 2.2bar. ITHR was induced in the mixtures containing predominantly ethanol through the addition of small amounts of n-heptane. After a critical threshold, additional n-heptane content yielded low temperature heat release (LTHR). A method for quantifying the amount of heat released during ITHR was developed by examining the second derivative of heat release, and this method was then used to identify trends in the engine data. The combustion process inside the engine was modeled using a single-zone HCCI model, and good qualitative agreement of pre-ignition pressure rise and heat release rate was found between experimental and modeling results using a detailed n-heptane/ethanol chemical kinetic model. The simulation results were used to identify the dominant reaction pathways contributing to ITHR, as well as to verify the chemical basis behind the quantification of the amount of ITHR in the experimental analysis. The dominant reaction pathways contributing to ITHR were found to be H-atom abstraction from n-heptane by OH and the addition of fuel radicals to O2. © 2013 The Combustion Institute.

  13. Advancing the Limits of Dual Fuel Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Koenigsson, Fredrik

    2012-07-01

    There is a growing interest in alternative transport fuels. There are two underlying reasons for this interest; the desire to decrease the environmental impact of transports and the need to compensate for the declining availability of petroleum. In the light of both these factors the Diesel Dual Fuel, DDF, engine is an attractive concept. The primary fuel of the DDF engine is methane, which can be derived both from renewables and from fossil sources. Methane from organic waste; commonly referred to as biomethane, can provide a reduction in greenhouse gases unmatched by any other fuel. The DDF engine is from a combustion point of view a hybrid between the diesel and the otto engine and it shares characteristics with both. This work identifies the main challenges of DDF operation and suggests methods to overcome them. Injector tip temperature and pre-ignitions have been found to limit performance in addition to the restrictions known from literature such as knock and emissions of NO{sub x} and HC. HC emissions are especially challenging at light load where throttling is required to promote flame propagation. For this reason it is desired to increase the lean limit in the light load range in order to reduce pumping losses and increase efficiency. It is shown that the best results in this area are achieved by using early diesel injection to achieve HCCI/RCCI combustion where combustion phasing is controlled by the ratio between diesel and methane. However, even without committing to HCCI/RCCI combustion and the difficult control issues associated with it, substantial gains are accomplished by splitting the diesel injection into two and allocating most of the diesel fuel to the early injection. HCCI/RCCI and PPCI combustion can be used with great effect to reduce the emissions of unburned hydrocarbons at light load. At high load, the challenges that need to be overcome are mostly related to heat. Injector tip temperatures need to be observed since the cooling effect of

  14. Dynamic-Stability Characteristics of Premixed Methane Oxy-Combustion

    KAUST Repository

    Shroll, Andrew P.

    2012-01-01

    This work explores the dynamic stability characteristics of premixed CH 4/O 2/CO 2 mixtures in a 50 kW swirl stabilized combustor. In all cases, the methane-oxygen mixture is stoichiometric, with different dilution levels of carbon dioxide used to control the flame temperature (T ad). For the highest T ad\\'s, the combustor is unstable at the first harmonic of the combustor\\'s natural frequency. As the temperature is reduced, the combustor jumps to fundamental mode and then to a low-frequency mode whose value is well below the combustor\\'s natural frequency, before eventually reaching blowoff. Similar to the case of CH 4/air mixtures, the transition from one mode to another is predominantly a function of the T ad of the reactive mixture, despite significant differences in laminar burning velocity and/or strained flame consumption speed between air and oxy-fuel mixtures for a given T ad. High speed images support this finding by revealing similar vortex breakdown modes and thus similar turbulent flame geometries that change as a function of flame temperature. Copyright © 2012 American Society of Mechanical Engineers.

  15. Effect of fuel characteristics on synthesis of calcium hydroxyapatite by solution combustion route

    Indian Academy of Sciences (India)

    Samir K Ghosh; Asit Prakash; Someswar Datta; Sujit K Roy; Debabrata Basu

    2010-02-01

    The effect of fuel characteristics on the processing of nano sized calcium hydroxyapatite (HA) fine powders by the solution combustion technique is reported. Urea, glycine and glucose were used as fuels in this study. By using different combinations of urea and glycine fuels and occasional addition of small amounts of highly water-soluble glucose, the flame temperature (f) of the process as well as product characteristics could be controlled easily. The powders obtained by this modified solution combustion technique were characterized by XRD, FTIR spectroscopy, SEM, FESEM–EDX, particle size analyser (PSD) and specific surface area (SSA) measurements. The particle size of phase pure HA powder was found to be < 20 nm in this investigation. The effects of glucose addition with stoichiometric ( = 1) and fuel excess ( > 1) urea and glycine precursor batches were investigated separately.

  16. Fuel properties and combustion characteristics of some promising bamboo species in India

    Institute of Scientific and Technical Information of China (English)

    Ritesh Kumar; N.Chandrashekar

    2014-01-01

    We investigated the fuel characteristics of five important bamboo species viz., Dendrocalamus strictus, D. brandisii, D. stocksii, Bambusa bambos and B. balcooa. The selected species cover more than 85%of the total growing stock of bamboo in India. Basic density varied from 0.48 to 0.78 g⋅cm-3 among the bamboo species studied. Ash content, volatile matter content and fixed carbon content ranged between 1.4%-3.0%, 77.2%-80.8%and 17.6%-21.1%, respectively. Variation in calorific value (18.7-19.6 MJ⋅kg-1) was marginal. Fuel value index var-ied widely (586-2120) among bamboo species. The highest calorific value (19.6 MJ⋅kg-1) and fuel value index (2120) were found in B. bal-cooa. Ash elemental analysis revealed that silica and potassium are the major ash forming minerals in bamboo biomass. Silica content ranged from 8.7%to 49.0%, while potassium ranged from 20.6%to 69.8%. We studied combustion characteristics under oxidizing atmosphere. Burning profiles of the samples were derived by applying the derivative thermo-gravimetric technique which is discussed in detail. The five bamboo species were different in their combustion behaviour, mainly due to differences in physical and chemical properties. We compare fuel prop-erties, ash elemental analysis and combustion characteristics of bamboo biomass with wood biomass of Eucalyptus hybrid (Eucalyptus tereticor-nis × Eucalyptus camaldulensis).

  17. [Study on expert system of infrared spectral characteristic of combustible smoke agent].

    Science.gov (United States)

    Song, Dong-ming; Guan, Hua; Hou, Wei; Pan, Gong-pei

    2009-05-01

    The present paper studied the application of expert system in prediction of infrared spectral characteristic of combustible anti-infrared smoke agent. The construction of the expert system was founded, based on the theory of minimum free energy and infrared spectral addition. After the direction of smoke agent was input, the expert system could figure out the final combustion products. Then infrared spectrogram of smoke could also be simulated by adding the spectra of all of the combustion products. Meanwhile, the screening index of smoke was provided in the wave bands of 3-5 im and 8-14 microm. FTIR spectroscope was used to investigate the performance of one kind of HC smoke. The combustion products calculated by the expert system were coincident with the actual data, and the simulant infrared spectrum was also similar to the real one of the smoke. The screening index given by the system was consistent with the known facts. It was showed that a new approach was offered for the fast discrimination of varieties of directions of smoke agent.

  18. Combustion characteristics of low concentration coal mine methane in divergent porous media burner

    Institute of Scientific and Technical Information of China (English)

    Lin Baiquan; Dai Huaming⇑; Wang Chaoqun; Li Qingzhao; Wang Ke; Zheng Yuanzhen

    2014-01-01

    Low-concentration methane (LCM) has been one of the biggest difficulties in using coal mine methane. And previous studies found that premixed combustion in porous media is an effective method of low cal-orific gas utilization. This paper studied the combustion of LCM in a divergent porous medium burner (DPMB) by using computational fluid dynamics (CFD), and investigated the effect of gas initial tempera-ture on combustion characteristic, the distribution of temperature and pollutant at different equivalence ratios in detail. Besides, the comparison of divergent and cylindrical burners was also performed in this paper. The results show that:the peak temperature in DPMB increases as the increasing of equivalence ratio, which is also suitable for the outlet NO discharge;the linear correlation is also discovered between peak temperature and equivalence ratios;NO emission at the initial temperature of 525 K is 5.64 times, larger than NO emission at the initial temperature of 300 K. Thus, it is preferable to balance the effect of thermal efficiency and environment simultaneously when determining the optimal initial temperature range. The working parameter limits of divergent burner are wider than that of cylindrical one which contributes to reducing the influence of LCM concentration and volume fluctuation on combustion.

  19. Combustion characteristics of a direct-injection diesel engine fueled with Fischer-Tropsch diesel

    Institute of Scientific and Technical Information of China (English)

    HUANG Yongcheng; ZHOU Longbao; PAN Keyu

    2007-01-01

    Fischer-Tropsch (F-T) diesel fuel is characterized by a high cetane number, a near-zero sulphur content and a very low aromatic level. On the basis of the recorded incylinder pressures and injector needle lifts, the combustion characteristics of an unmodified single-cylinder directinjection diesel engine operating on F-T diesel fuel are analyzed and compared with those of conventional diesel fuel operation. The results show that F-T diesel fuel exhibits a slightly longer injection delay and injection duration, an average of 18.7% shorter ignition delay, and a comparable total combustion duration when compared to those of conventional diesel fuel. Meanwhile, F-T diesel fuel displays an average of 26.8% lower peak value of premixed burning rate and a higher peak value of diffusive burning rate. In addition, the F-T diesel engine has a slightly lower peak combustion pressure, a far lower rate of pressure rise, and a lower mechanical load and combustion noise than the conventional diesel engine. The brake specific fuel consumption is lower and the effective thermal efficiency is higher for F-T diesel fuel operation.

  20. Combustion characteristics of lemongrass (Cymbopogon flexuosus oil in a partial premixed charge compression ignition engine

    Directory of Open Access Journals (Sweden)

    Avinash Alagumalai

    2015-09-01

    Full Text Available Indeed, the development of alternate fuels for use in internal combustion engines has traditionally been an evolutionary process in which fuel-related problems are met and critical fuel properties are identified and their specific limits defined to resolve the problem. In this regard, this research outlines a vision of lemongrass oil combustion characteristics. In a nut-shell, the combustion phenomena of lemongrass oil were investigated at engine speed of 1500 rpm and compression ratio of 17.5 in a 4-stroke cycle compression ignition engine. Furthermore, the engine tests were conducted with partial premixed charge compression ignition-direct injection (PCCI-DI dual fuel system to profoundly address the combustion phenomena. Analysis of cylinder pressure data and heat-release analysis of neat and premixed lemongrass oil were demonstrated in-detail and compared with conventional diesel. The experimental outcomes disclosed that successful ignition and energy release trends can be obtained from a compression ignition engine fueled with lemongrass oil.

  1. Combustion Mode Design with High Efficiency and Low Emissions Controlled by Mixtures Stratification and Fuel Reactivity

    Directory of Open Access Journals (Sweden)

    Hu eWang

    2015-08-01

    Full Text Available This paper presents a review on the combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixture stratification that have been conducted in the authors’ group, including the charge reactivity controlled homogeneous charge compression ignition (HCCI combustion, stratification controlled premixed charge compression ignition (PCCI combustion, and dual-fuel combustion concepts controlled by both fuel reactivity and mixture stratification. The review starts with the charge reactivity controlled HCCI combustion, and the works on HCCI fuelled with both high cetane number fuels, such as DME and n-heptane, and high octane number fuels, such as methanol, natural gas, gasoline and mixtures of gasoline/alcohols, are reviewed and discussed. Since single fuel cannot meet the reactivity requirements under different loads to control the combustion process, the studies related to concentration stratification and dual-fuel charge reactivity controlled HCCI combustion are then presented, which have been shown to have the potential to achieve effective combustion control. The efforts of using both mixture and thermal stratifications to achieve the auto-ignition and combustion control are also discussed. Thereafter, both charge reactivity and mixture stratification are then applied to control the combustion process. The potential and capability of thermal-atmosphere controlled compound combustion mode and dual-fuel reactivity controlled compression ignition (RCCI/highly premixed charge combustion (HPCC mode to achieve clean and high efficiency combustion are then presented and discussed. Based on these results and discussions, combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixtures stratification in the whole operating range is proposed.

  2. Effectiveness of oxygen enriched hydrogen-HHO gas addition on DI diesel engine performance, emission and combustion characteristics

    National Research Council Canada - National Science Library

    Premkartikkumar S.R; Annamalai K; Pradeepkumar A.R

    2014-01-01

    Nowadays, more researches focus on protecting the environment. Present investigation concern with the effectiveness of Oxygen Enriched hydrogen- HHO gas addition on performance, emission and combustion characteristics of a DI diesel engine...

  3. Combustion, performance and emissions characteristics of a newly developed CRDI single cylinder diesel engine

    Indian Academy of Sciences (India)

    Avinash Kumar Agarwal; Paras Gupta; Atul Dhar

    2015-09-01

    For improving engine performance, combustion and controlling emissions from compression ignition (CI) engines, common rail direct injection (CRDI) technology offers limitless possibilities by controlling fuel injection parameters such as fuel injection pressure, start of injection (SOI) timing, rate of fuel injection and injection duration. CRDI systems available commercially are quite complex and use a large number of sensors, hardware and analytical circuits, which make them very expensive and unfeasible for cheaper single cylinder engines, typically used in agricultural sector and decentralized power sector. This paper covers experimental investigations of a simpler version of CRDI system developed for a constant-speed, single-cylinder engine. Modifications in the cylinder head for accommodating solenoid injector, designing injector driver circuit and development of high pressure stage controls were some of the engine modification and development tasks undertaken. SOI timing is an important parameter for improving engine's combustion characteristics. SOI timings were varied between 25° and 40° BTDC for investigating engine's performance, emissions and combustion characteristics. Advanced fuel injections showed higher heat release rate (HRR), cylinder pressure and rate of pressure rise (RoPR) because of relatively longer ignition delay experienced. Lowest brake specific fuel consumption (BSFC) was obtained for 34° CA BTDC SOI. Reduction in engine out emissions except NOx was observed for advanced fuel injection timings for this newly developed CRDI system.

  4. Combustion, emission and engine performance characteristics of used cooking oil biodiesel - A review

    Energy Technology Data Exchange (ETDEWEB)

    Enweremadu, C.C. [Department of Mechanical Engineering, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900 (South Africa); Rutto, H.L. [Department of Chemical Engineering, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900 (South Africa)

    2010-12-15

    As the environment degrades at an alarming rate, there have been steady calls by most governments following international energy policies for the use of biofuels. One of the biofuels whose use is rapidly expanding is biodiesel. One of the economical sources for biodiesel production which doubles in the reduction of liquid waste and the subsequent burden of sewage treatment is used cooking oil (UCO). However, the products formed during frying, such as free fatty acid and some polymerized triglycerides, can affect the transesterification reaction and the biodiesel properties. This paper attempts to collect and analyze published works mainly in scientific journals about the engine performance, combustion and emissions characteristics of UCO biodiesel on diesel engine. Overall, the engine performance of the UCO biodiesel and its blends was only marginally poorer compared to diesel. From the standpoint of emissions, NOx emissions were slightly higher while un-burnt hydrocarbon (UBHC) emissions were lower for UCO biodiesel when compares to diesel fuel. There were no noticeable differences between UCO biodiesel and fresh oil biodiesel as their engine performances, combustion and emissions characteristics bear a close resemblance. This is probably more closely related to the oxygenated nature of biodiesel which is almost constant for every biodiesel (biodiesel has some level of oxygen bound to its chemical structure) and also to its higher viscosity and lower calorific value, which have a major bearing on spray formation and initial combustion. (author)

  5. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Science.gov (United States)

    Balicki, Adrian; Bartela, Łukasz

    2014-06-01

    Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of `zeroemission' technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  6. Effect of Fuel Types on Combustion Characteristics and Performance of a Four Stroke IC Engine

    Directory of Open Access Journals (Sweden)

    Mrs. Rana Ali Hussein,

    2014-04-01

    Full Text Available In this study, the effect of Gasoline, Ethanol, Gasohol E10, and Kerosene on the performance and combustion characteristics of a spark ignition (SI engine were investigated. In the experiment, the internal combustion (IC engine includes one cylinder, two valves, and four stroke spark ignition. Performance tests were carried out for specific fuel consumption, brake specific fuel consumption, power developed, corrosion rate, and carbon dioxide (CO2 and carbon monoxide (CO emissions. The measurements were conducted under various engine speeds ranging from 1500 to 4500 rpm. The experimental results showed that the performance of engine was improved with the use of gasoline and gasohol E10 in comparison with the Ethanol and Kerosene. The concentrations of CO2 and CO were presented and compared for all type of fuel examined.

  7. Emission and Combustion Characteristics of Si Engine Working Under Gasoline Blended with Ethanol Oxygenated Organic Compounds

    Directory of Open Access Journals (Sweden)

    Dhanapal Balaji

    2010-01-01

    Full Text Available Problem statement: The objective of this study is to investigate the effect of using unleaded gasoline and additives blends on Spark Ignition engine (SI engine combustion and exhaust emission. Approach: A four stroke, single cylinder SI engine was used for conducting this study. Exhaust emissions were analysed for Carbon Monoxide (CO, Hydrocarbon (HC and Oxides of Nitrogen (NOx and carbon dioxide (CO2 using unleaded gasoline and additives blends with different percentages of fuel at varying engine torque condition and constant engine speed. Results: The result showed that the blending of unleaded gasoline increases the octane number and power output this may leads to increase the brake thermal efficiency. The CO, HC and NOx emissions concentrations in the engine exhaust decreases while the CO2 concentration increases. Conclusion: Using ethanol as a fuel additive to unleaded gasoline causes an improvement in combustion characteristics and significant reduction in exhaust emissions.

  8. Influence of Valve's Characteristic on Total Performance of Three Cylinders Internal Combustion Water Pump

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hongxin; ZHANG Tiezhu; WANG Weichao

    2009-01-01

    lntenal combustion pump (ICP) is a new type power device turning the thermal energy from fuel combustion into fluid pressure energy. Three cylinders prototype has just been developed. The study on the influence of valve's characteristic on ICP's total performance will found the base for its optimum design. Based on the theoretical and testing fruits of single cylinder prototype, the performance of the valves and complete appliance of the latest is simulated. When the natural frequency of valves is approximately to the round number times of the working frequency, volumetric efficiency is seriously low. The nominal rotational speed of the prototype is nearly to the speed where the volumetric efficiency is lowest, which is harmful to the normal work of ICP, so further structure optimization of valves should be carried out. The change of volumetric efficiency has great influence on the fuel consumption rate,output flow, effective thermal efficiency, effective power, and so on, but little on output pressure.

  9. Combustion characteristics of semicokes derived from pyrolysis of low rank bituminous coal

    Institute of Scientific and Technical Information of China (English)

    Qian Wei; Xie Qiang; Huang Yuyi; Dang Jiatao; Sun Kaidi; Yang Qian; Wang Jincao

    2012-01-01

    Various semicokes were obtained from medium-low temperature pyrolysis of Dongrong long flame coal.The proximate analysis,calorific value and Hardgrove grindability index (HGI) of semicokes were determined,and the ignition temperature,burnout temperature,ignition index,burnout index,burnout ratio,combustion characteristic index of semicokes were measured and analyzed using thermogravimetry analysis (TGA).The effects of pyrolysis temperature,heating rate,and pyrolysis time on yield,composition and calorific value of long flame coal derived semicokes were investigated,especially the influence of pyrolysis temperature on combustion characteristics and grindability of the semicokes was studied combined with X-ray diffraction (XRD) analysis of semicokes.The results show that the volatile content,ash content and calorific value of semicokes pyrolyzed at all process parameters studied meet the technical specifications of the pulverized coal-fired furnaces (PCFF) referring to China Standards GB/T 7562-1998.The pyrolysis temperature is the most influential factor among pyrolysis process parameters.As pyrolysis temperature increases,the yield,ignition index,combustion reactivity and burnout index of semicokes show a decreasing tend,but the ash content increases.In the range of 400 and 450 ℃,the grindability of semicokes is rational,especially the grindability of semicokes pyrolyzed at 450 ℃ is suitable.Except for the decrease of volatile content and increase of ash content,the decrease of combustion performance of semicokes pyrolyzed at higher temperature should be attributed to the improvement of the degree of structural ordering and the increase of aromaticity and average crystallite size of char.It is concluded that the semicokes pyrolyzed at the temperature of 450 ℃ is the proper fuel for PCFF.

  10. Three-stage autoignition of gasoline in an HCCI engine: An experimental and chemical kinetic modeling investigation

    Energy Technology Data Exchange (ETDEWEB)

    Machrafi, Hatim; Cavadias, Simeon [UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris (France); UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert (France)

    2008-12-15

    The alternative HCCI combustion mode presents a possible means for decreasing the pollution with respect to conventional gasoline or diesel engines, while maintaining the efficiency of a diesel engine or even increasing it. This paper investigates the possibility of using gasoline in an HCCI engine and analyzes the autoignition of gasoline in such an engine. The compression ratio that has been used is 13.5, keeping the inlet temperature at 70 C, varying the equivalence ratio from 0.3 to 0.54, and the EGR (represented by N{sub 2}) ratio from 0 to 37 vol%. For comparison, a PRF95 and a surrogate containing 11 vol% n-heptane, 59 vol% iso-octane, and 30 vol% toluene are used. A previously validated kinetic surrogate mechanism is used to analyze the experiments and to yield possible explanations to kinetic phenomena. From this work, it seems quite possible to use the high octane-rated gasoline for autoignition purposes, even under lean inlet conditions. Furthermore, it appeared that gasoline and its surrogate, unlike PRF95, show a three-stage autoignition. Since the PRF95 does not contain toluene, it is suggested by the kinetic mechanism that the benzyl radical, issued from toluene, causes this so-defined ''obstructed preignition'' and delaying thereby the final ignition for gasoline and its surrogate. The results of the kinetic mechanism supporting this explanation are shown in this paper. (author)

  11. Investigation on Flame Characteristics and Burner Operability Issues of Oxy-Fuel Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Choudhuri, Ahsan [Univ. Of Texas, El Paso, TX (United States)

    2013-09-30

    Oxy-fuel combustion has been used previously in a wide range of industrial applications. Oxy- combustion is carried out by burning a hydrocarbon fuel with oxygen instead of air. Flames burning in this configuration achieve higher flame temperatures which present opportunities for significant efficiency improvements and direct capture of CO2 from the exhaust stream. In an effort to better understand and characterize the fundamental flame characteristics of oxy-fuel combustion this research presents the experimental measurements of flame stability of various oxyfuel flames. Effects of H2 concentration, fuel composition, exhaust gas recirculation ratio, firing inputs, and burner diameters on the flame stability of these fuels are discussed. Effects of exhaust gas recirculation i.e. CO2 and H2O (steam) acting as diluents on burner operability are also presented. The roles of firing input on flame stability are then analyzed. For this study it was observed that many oxy-flames did not stabilize without exhaust gas recirculation due to their higher burning velocities. In addition, the stability regime of all compositions was observed to decrease as the burner diameter increased. A flashback model is also presented, using the critical velocity gradient gF) values for CH4-O2-CO2 flames. The second part of the study focuses on the experimental measurements of the flow field characteristics of premixed CH4/21%O2/79%N2 and CH4/38%O2/72%CO2 mixtures at constant firing input of 7.5 kW, constant, equivalence ratio of 0.8, constant swirl number of 0.92 and constant Reynolds Numbers. These measurements were taken in a swirl stabilized combustor at atmospheric pressure. The flow field visualization using Particle Imaging Velocimetry (PIV) technique is implemented to make a better understanding of the turbulence characteristics of

  12. Multi-dimensional Modeling of the Application of Catalytic Combustion to Homogeneous Charge Compression Ignition Engine

    Institute of Scientific and Technical Information of China (English)

    Wen Zeng; MaoZhao Xie

    2006-01-01

    The detailed surface reaction mechanism of methane on rhodium catalyst was analyzed.Comparisons between numerical simulation and experiments showed a basic agreement.The combustion process of homogeneous charge compression ignition (HCCI) engine whose piston surface has been coated with catalyst (rhodium and platinum) was numerically investigated.A multi-dimensional model with detailed chemical kinetics was built.The effects of catalytic combustion on the ignition timing,the temperature and CO concentration fields,and HC,CO and NOx emissions of the HCCI engine were discussed.The results showed the ignition timing of the HCCI engine was advanced and the emissions of HC and CO were decreased by the catalysis.

  13. Investigation on the effect of diaphragm on the combustion characteristics of solid-fuel ramjet

    Science.gov (United States)

    Gong, Lunkun; Chen, Xiong; Yang, Haitao; Li, Weixuan; Zhou, Changsheng

    2017-10-01

    The flow field characteristics and the regression rate distribution of solid-fuel ramjet with three-hole diaphragm were investigated by numerical and experimental methods. The experimental data were obtained by burning high-density polyethylene using a connected-pipe facility to validate the numerical model and analyze the combustion efficiency of the solid-fuel ramjet. The three-dimensional code developed in the present study adopted three-order MUSCL and central difference schemes, AUSMPW + flux vector splitting method, and second-order moment turbulence-chemistry model, together with k-ω shear stress transport (SST) turbulence model. The solid fuel surface temperature was calculated with fluid-solid heat coupling method. The numerical results show that strong circumferential flow exists in the region upstream of the diaphragm. The diaphragm can enhance the regression rate of the solid fuel in the region downstream of the diaphragm significantly, which mainly results from the increase of turbulent viscosity. As the diaphragm port area decreases, the regression rate of the solid fuel downstream of the diaphragm increases. The diaphragm can result in more sufficient mixing between the incoming air and fuel pyrolysis gases, while inevitably producing some pressure loss. The experimental results indicate that the effect of the diaphragm on the combustion efficiency of hydrocarbon fuels is slightly negative. It is conjectured that the diaphragm may have some positive effects on the combustion efficiency of the solid fuel with metal particles.

  14. Combustion Characteristics of Chlorine-Free Solid Fuel Produced from Municipal Solid Waste by Hydrothermal Processing

    Directory of Open Access Journals (Sweden)

    Kunio Yoshikawa

    2012-11-01

    Full Text Available An experimental study on converting municipal solid waste (MSW into chlorine-free solid fuel using a combination of hydrothermal processing and water-washing has been performed. After the product was extracted from the reactor, water-washing experiments were then conducted to obtain chlorine-free products with less than 3000 ppm total chlorine content. A series of combustion experiments were then performed for the products before and after the washing process to determine the chlorine content in the exhaust gas and those left in the ash after the combustion process at a certain temperature. A series of thermogravimetric analyses were also conducted to compare the combustion characteristics of the products before and after the washing process. Due to the loss of ash and some volatile matter after washing process, there were increases in the fixed carbon content and the heating value of the product. Considering the possible chlorine emission, the washing process after the hydrothermal treatment should be necessary only if the furnace temperature is more than 800 °C.

  15. New black liquor combustion characteristics II; Mustalipeaen uudet poltto-ominaisuudet II

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Backman, R.; Bostroem, S.; Forssen, M.; Uusikartano, T. [Aabo Akademi, Turku (Finland)

    1996-12-01

    In an earlier study (LIEKKI 2, Y 17), the combustion characteristics of 17 liquors of different origin were studied by four laboratory tests. These tests were (1) single droplet burning, (2) single droplet pyrolysis, (3) pressurized gasification, and (4) calculation of melting properties of inorganic carryover particles. The study showed that there are big differences between liquors of different origin. These differences strongly affect the combustion properties, i.e. pyrolysis and burning times, swelling, and fouling tendency of heat transfer surfaces. The objective for the present research project was to investigate the reasons why some properties affect the combustion behavior more than others. The project is partly complementary to the previous study, partly a more detailed study of some of the phenomena observed earlier. The work constitutes of the following studies: (1) further study of several more liquors by the same methods, (2) pyrolysis swelling in inert gas (N{sub 2}) at two temperatures, 700 deg C and 900 deg C, (3) effect of heat treatment black liquors, (4) effect of addition of sodium compounds to a virgin black liquor, (5) data treatment and correlations, (6) nitrogen oxide formation tendency. (author)

  16. 缸内直喷汽油机HCCI燃烧对压缩比和辛烷值的适应性研究%Dependence of HCCI Combustion on Compression Ratio and Fuel Property in a Gasoline Direct Injection Engine

    Institute of Scientific and Technical Information of China (English)

    王志; 杨俊伟; 张志福; 葛强强; 田国弘; 王建昕

    2007-01-01

    在缸内直喷汽油机(GDI)上采用多次燃油喷射和可变配气技术来控制缸内混合气形成和燃烧,实现了SI/HCCI复合燃烧方式.研究了不同压缩比和辛烷值对均质混合气压燃(HCCI)燃烧排放特性的影响.结果表明,汽油HCCI燃烧呈现单阶段燃烧燃料特性,HCCI着火发生在上止点附近时油耗低.低压缩比下,HCCI燃烧可以在较浓空燃比下工作,NOx排放较高.高辛烷值燃料HCCI燃烧可运行的负荷范围窄.汽油HCCI发动机在偏高压缩比条件下燃用偏低辛烷值汽油可以获得较好的经济性和排放性能.

  17. Combustion characteristics of eastern white pine bark and Douglas fir planer shavings. Technical Progress Report No. 5, September 16, 1977--September 15, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Junge, D.C.

    1978-12-01

    Significant quantities of wood residue fuels are presently being used in industrial steam generating facilities. Recent studies indicate that substantial additional quantities of wood residue fuels are available for energy generation in the form of steam and/or electricity. A limited data base on the combustion characteristics of wood residue fuels has resulted in the installation and operation of inefficient combustion systems for these fuels. This investigation of the combustion characteristics of wood residue fuels was undertaken to provide a data base which could be used to optimize the combustion of such fuels. Optimization of the combustion process in industrial boilers serves to improve combustion efficiency and to reduce air pollutant emissions generated in the combustion process. Data are presented on the combustion characteristics of eastern white pine bark mixed with Douglas fir planer shavings.

  18. Investigation of the combustion characteristics of Zonguldak bituminous coal using DTA and DTG

    Energy Technology Data Exchange (ETDEWEB)

    Haykiri-Acma, H.; Yaman, S.; Kucukbayrak, S.; Okutan, H. [Istanbul Technical University, Istanbul (Turkey). Dept. of Chemical Engineering

    2006-06-21

    Combustion characteristics of coking, semicoking, and noncoking Turkish bituminous coal samples from Zonguldak basin were investigated applying differential thermal analysis (DTA) and differential thermogravimetry (DTG) techniques. Results were compared with that of the coke from Zonguldak bituminous coal, a Turkish lignite sample from Soma, and a Siberian bituminous coal sample. The thermal data from both techniques showed some differences depending on the proximate analyses of the samples. Noncombustible components of the volatile matter led to important changes in thermal behavior. The data front both methods were, evaluated jointly, and some thermal properties were interpreted considering these methods in a complementary combination.

  19. Combustion characteristics of spark-ignition and pilot flame ignition systems in a model Wankel stratified charge engine

    Energy Technology Data Exchange (ETDEWEB)

    Muroki, T. [Kanagawa Inst. of Technology, Dept. of Mechanical Engineering, Kanagawa (Japan); Moriyoshi, Y. [Chiba Univ., Dept. of Electronics and Mechanical Engineering, Chiba (Japan)

    2000-11-01

    In a stratified charge engine, a glow plug pilot flame ignition system has been compared with a spark-ignition system for a model stratified charge Wankel combustion chamber. A motored two-stroke diesel engine was operated as a rapid compression and expansion machine with the cylinder head replaced by a model Wankel combustion chamber designed to simulate the temporal changes of air flow and pressure fields inside the chamber of an actual engine. It was found that the pilot flame ignition system had better ignitability and improved combustion characteristics, especially in the lean mixture range, relative to the spark-ignition system. (Author)

  20. Combustion Characteristics in a Non-Premixed Cool-Flame Regime of n-Heptane in Microgravity

    Science.gov (United States)

    Takahashi, Fumiaki; Katta, Viswanath R.; Hicks, Michael C.

    2015-01-01

    A series of distinct phenomena have recently been observed in single-fuel-droplet combustion tests performed on the International Space Station (ISS). This study attempts to simulate the observed flame behavior numerically using a gaseous n-heptane fuel source in zero gravity and a time-dependent axisymmetric (2D) code, which includes a detailed reaction mechanism (127 species and 1130 reactions), diffusive transport, and a radiation model (for CH4, CO, CO2, H2O, and soot). The calculated combustion characteristics depend strongly on the air velocity around the fuel source. In a near-quiescent air environment (combustion experiments.

  1. MTU series 1600 HCCI engine with extremely low exhaust emissions over the entire engine map; HCCI-Motor der MTU Baureihe 1600 mit extrem niedrigen Abgasemissionen im gesamten Motorkennfeld

    Energy Technology Data Exchange (ETDEWEB)

    Teetz, Christoph; Bergmann, Dirk; Sauer, Christina; Schneemann, Arne [MTU, Friedrichshafen (Germany); Eichmeier, Johannes; Spicher, Ulrich [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). IFKM

    2012-11-01

    The main challenge when developing off-highway engines is to keep emissions within the limits to apply in the future while maintaining low fuel consumption and low CO{sub 2} output. In the USA in particular, diesel engines in the 130 - 560 kW power range are to be subject from 2014 to EPA Tier 4 legislation, which imposes limits of 0.4 g/kWh for NO{sub x} and 0.02 g/kWh for particulate matter. Diesel units can only satisfy those requirements using a combination of in-engine measures and exhaust aftertreatment systems (SCR, particulate filters), which makes them a good deal more complex and expensive. In the face of CO{sub 2} emissions regulations and the growing demand for diesel fuel, greater emphasis is now being placed on alternative fuels. Homogeneous Charge Compression Ignition or 'HCCI' provides an alternative to complex exhaust aftertreatment systems which generates virtually no soot or nitrous oxide emissions. It does, however, present new challenges with respect to combustion control and engine load. Up to the present, it has not been possible to exploit the full potential of this combustion process over the entire engine map, since the high ignition performance of diesel fuel at high loads results in excessively early combustion and inadmissible pressure gradients. The pre-development department of MTU Friedrichshafen worked with the Institute of Internal Combustion Engines at the Karlsruhe Institute of Technology (KIT) to devise a research prototype for an industrial application which would allow semi-homogenous combustion with controlled self-ignition over the full engine map. The engine is based on a 6-cylinder version of the MTU Series 1600 unit and has a rated output of 300 kW. The fuels - gasoline or ethanol and diesel - are mixed in such a way as to avoid the disadvantages associated with most HCCI processes. Since the use of ethanol also enhances combustion efficiency, it has a two-fold positive effect on the CO{sub 2} situation. With

  2. Experimental research on spray and combustion characteristics of the third generation conical spray

    Institute of Scientific and Technical Information of China (English)

    FENG Li-yan; LONG Wu-qiang; DU Bao-guo; TIAN hua; OBOKATA Tomio

    2005-01-01

    A new generation conical spray system for conventional diesel engines or premixed combustion diesel engines is introduced. By means of oriented impingement method, flexible spray penetration in design is realized. High-speed photograph was used to investigate the spatial distribution characteristics of the new spray for cases of different impingement angles and needle valve opening pressures. The results show that, by applying spray impingement orientation, fuel jets spread along the cone surface as shape of sectors, so the dispersion of jets is increased obviously. Changing on impingement angle leads to variation of penetration, which is critical in homogeneous mixture preparation. Due to the flexibility of spray penetration in design, the spray impingement on liner is avoided in a great extent. The results also indicate that higher needle valve opening pressure results in longer penetration and larger spray angle after impingement. Combustion characteristics of the impinged conical spray were studied in the 1135 type diesel engine. The new impinged conical spray system work smoothly in full load range with better fuel economy and lower emissions of NOx and soot than the original test engine.

  3. Combustion characteristics of a turbocharged DI compression ignition engine fueled with petroleum diesel fuels and biodiesel.

    Science.gov (United States)

    Canakci, Mustafa

    2007-04-01

    In this study, the combustion characteristics and emissions of two different petroleum diesel fuels (No. 1 and No. 2) and biodiesel from soybean oil were compared. The tests were performed at steady state conditions in a four-cylinder turbocharged DI diesel engine at full load at 1400-rpm engine speed. The experimental results compared with No. 2 diesel fuel showed that biodiesel provided significant reductions in PM, CO, and unburned HC, the NO(x) increased by 11.2%. Biodiesel had a 13.8% increase in brake-specific fuel consumption due to its lower heating value. However, using No. 1 diesel fuel gave better emission results, NO(x) and brake-specific fuel consumption reduced by 16.1% and 1.2%, respectively. The values of the principal combustion characteristics of the biodiesel were obtained between two petroleum diesel fuels. The results indicated that biodiesel may be blended with No. 1 diesel fuel to be used without any modification on the engine.

  4. Non-Petroleum-Based Fuels: Report on the Relationship Between Molecular Structure and Compression Ignition Fuels, Both Conventional and HCCI

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Joshua [National Renewable Energy Lab. (NREL), Golden, CO (United States); McCormick, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Clark, Wendy [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2004-08-01

    The U.S. Department of Energy (DOE) is committed to increasing our nation’s energy security by decreasing our dependence on imported petroleum. The Fuels Technologies Subprogram within DOE’s Office of Freedom Car and Vehicle Technology (OFCVT) supports research that allows the United States to develop advanced fuels that enable efficient engines with low emissions. This document reports the completion of NREL FY 2004 Annual Operating Plan milestone 10.2: “Report on the relationship between molecular structure and compression ignition fuels, both conventional and HCCI.” This work is an incremental step toward the OFCVT Multi-Year Program Plan APBF/NPBF Milestone No. 3: “Establish fuel and lubricant constituents that are required for advanced combustion regime engines.”

  5. Characteristics of flame spread over the surface of charring solid combustibles at high altitude

    Institute of Scientific and Technical Information of China (English)

    LI Jie; JI Jie; ZHANG Ying; SUN JinHua

    2009-01-01

    To explore the characteristics of flame spread over the surface of charring solid combustibles at high altitude, the whitewood with uniform texture was chosen to conduct a series of experiments in Lhasa and Hefei, with altitude of 3658 m and 50 m respectively. Several parameters, including the flame height, flame spread rate, flame temperature, surface temperature, were measured on samples with different width and inclinations. A quantitative analysis of flame spread characteristics over sample surface at high altitude was performed. Results showed that, in the environment of lower pressure and oxygen concentration at high altitude, the flame height and flame spread rate over sample surface decreased, but the flame temperature increased slightly. However, with increasing of sample width, the relative difference between the flame spread rates at different altitudes decreased.

  6. Advanced Start of Combustion Sensor Phases I and II-A: Feasibility Demonstration, Design and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Chad Smutzer

    2010-01-31

    Homogeneous Compressed Charge Ignition (HCCI) has elevated the need for Start of Combustion (SOC) sensors. HCCI engines have been the exciting focus of engine research recently, primarily because HCCI offers higher thermal efficiency than the conventional Spark Ignition (SI) engines and significantly lower NOx and soot emissions than conventional Compression Ignition (CI) engines, and could be fuel neutral. HCCI has the potential to unify all the internal combustion engine technology to achieve the high-efficiency, low-emission goal. However, these advantages do not come easy. It is well known that the problems encountered with HCCI combustion center on the difficulty of controlling the Start of Combustion. TIAX has an SOC sensor under development which has shown promise. In previous work, including a DOE-sponsored SBIR project, TIAX has developed an accelerometer-based method which was able to determine SOC within a few degrees crank angle for a range of operating conditions. A signal processing protocol allows reconstruction of the combustion pressure event signal imbedded in the background engine vibration recorded by the accelerometer. From this reconstructed pressure trace, an algorithm locates the SOC. This SOC sensor approach is nonintrusive, rugged, and is particularly robust when the pressure event is strong relative to background engine vibration (at medium to high engine load). Phase I of this project refined the previously developed technology with an engine-generic and robust algorithm. The objective of the Phase I research was to answer two fundamental questions: Can the accelerometer-based SOC sensor provide adequate SOC event capture to control an HCCI engine in a feedback loop? And, will the sensor system meet cost, durability, and software efficiency (speed) targets? Based upon the results, the answer to both questions was 'YES'. The objective of Phase II-A was to complete the parameter optimization of the SOC sensor prototype in order

  7. Advanced Start of Combustion Sensor Phases I and II-A: Feasibility Demonstration, Design and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Chad Smutzer

    2010-01-31

    Homogeneous Compressed Charge Ignition (HCCI) has elevated the need for Start of Combustion (SOC) sensors. HCCI engines have been the exciting focus of engine research recently, primarily because HCCI offers higher thermal efficiency than the conventional Spark Ignition (SI) engines and significantly lower NOx and soot emissions than conventional Compression Ignition (CI) engines, and could be fuel neutral. HCCI has the potential to unify all the internal combustion engine technology to achieve the high-efficiency, low-emission goal. However, these advantages do not come easy. It is well known that the problems encountered with HCCI combustion center on the difficulty of controlling the Start of Combustion. TIAX has an SOC sensor under development which has shown promise. In previous work, including a DOE-sponsored SBIR project, TIAX has developed an accelerometer-based method which was able to determine SOC within a few degrees crank angle for a range of operating conditions. A signal processing protocol allows reconstruction of the combustion pressure event signal imbedded in the background engine vibration recorded by the accelerometer. From this reconstructed pressure trace, an algorithm locates the SOC. This SOC sensor approach is nonintrusive, rugged, and is particularly robust when the pressure event is strong relative to background engine vibration (at medium to high engine load). Phase I of this project refined the previously developed technology with an engine-generic and robust algorithm. The objective of the Phase I research was to answer two fundamental questions: Can the accelerometer-based SOC sensor provide adequate SOC event capture to control an HCCI engine in a feedback loop? And, will the sensor system meet cost, durability, and software efficiency (speed) targets? Based upon the results, the answer to both questions was 'YES'. The objective of Phase II-A was to complete the parameter optimization of the SOC sensor prototype in order

  8. Combustion characteristics of aluminium-iron oxidein SHS-gravitational process

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In order to get high quality of products, the combustion of aluminium-iron oxide thermite in SHS-gravitational process must be under control. The effects of thermite filling density, hole in thermite and inclined angle of pipe on combustion rate were studied. It shows that the combustion rate decreases with the decrease of filling density. The thermite combusts downwards the pipe much more quickly if there are holes in the thermite. And the combustion rate increases with the increase of the inclined angle of pipe. The experiment results show that the combustion of thermite is predominantly controlled by gas phasereaction, which is attributed to the high temperature of the thermitecombustion.

  9. A comparison of co-combustion characteristics of coal with wood and hydrothermally treated municipal solid waste.

    Science.gov (United States)

    Muthuraman, Marisamy; Namioka, Tomoaki; Yoshikawa, Kunio

    2010-04-01

    In this work, thermogravimetric analysis was used to investigate the co-combustion characteristics of wood and municipal solid waste (MSW) with Indian coal. Combustion characteristics like volatile release, ignition were studied. Wood presented an enhanced reaction rate reflecting its high volatile and low ash contents, while MSW enhanced ignition behavior of Indian coal. The results indicate that blending of both, wood and MSW improves devolatization properties of coal. Significant interaction was detected between wood and Indian coal, and reactivity of coal has improved upon blending with wood. On the other hand, MSW shows a good interaction with Indian coal leading to significant reduction in ignition temperature of coal and this effect was more pronounced with higher blending ratio of MSW. Hence MSW blending could more positively support the combustion of low quality Indian coal as compared to wood, due to its property of enhancement of ignition characteristics.

  10. Combustion characteristics of Malaysian oil palm biomass, sub-bituminous coal and their respective blends via thermogravimetric analysis (TGA).

    Science.gov (United States)

    Idris, Siti Shawalliah; Rahman, Norazah Abd; Ismail, Khudzir

    2012-11-01

    The combustion characteristics of Malaysia oil palm biomass (palm kernel shell (PKS), palm mesocarp fibre (PMF) and empty fruit bunches (EFB)), sub-bituminous coal (Mukah Balingian) and coal/biomass blends via thermogravimetric analysis (TGA) were investigated. Six weight ratios of coal/biomass blends were prepared and oxidised under dynamic conditions from temperature 25 to 1100°C at four heating rates. The thermogravimetric analysis demonstrated that the EFB and PKS evolved additional peak besides drying, devolatilisation and char oxidation steps during combustion. Ignition and burn out temperatures of blends were improved in comparison to coal. No interactions were observed between the coal and biomass during combustion. The apparent activation energy during this process was evaluated using iso-conversional model free kinetics which resulted in highest activation energy during combustion of PKS followed by PMF, EFB and MB coal. Blending oil palm biomass with coal reduces the apparent activation energy value.

  11. Combustion characteristics of fuel droplets with addition of nano and micron-sized aluminum particles

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Yanan; Qiao, Li [School of Aeronautics and Astronautics, Purdue University, West Lafayette, IN 47907 (United States)

    2011-02-15

    The burning characteristics of fuel droplets containing nano and micron-sized aluminum particles were investigated. Particle size, surfactant concentration, and the type of base fluid were varied. In general, nanosuspensions can last much longer than micron suspensions, and ethanol-based fuels were found to achieve much better suspension than n-decane-based fuels. Five distinctive stages (preheating and ignition, classical combustion, microexplosion, surfactant flame, and aluminum droplet flame) were identified for an n-decane/nano-Al droplet, while only the first three stages occurred for an n-decane/micron-Al droplet. For the same solid loading rate and surfactant concentration, the disruption and microexplosion behavior of the micron suspension occurred later with much stronger intensity. The intense droplet fragmentation was accompanied by shell rupture, which caused a massive explosion of particles, and most of them were burned during this event. On the contrary, for the nanosuspension, combustion of the large agglomerate at the later stage requires a longer time and is less complete because of formation of an oxide shell on the surface. This difference is mainly due to the different structure and characteristics of particle agglomerates formed during the early stage, which is a spherical, porous, and more-uniformly distributed aggregate for the nanosuspension, but it is a densely packed and impermeable shell for the micron suspension. A theoretical analysis was then conducted to understand the effect of particle size on particle collision mechanism and aggregation rate. The results show that for nanosuspensions, particle collision and aggregation are dominated by the random Brownian motion. For micron suspensions, however, they are dominated by fluid motion such as droplet surface regression, droplet expansion resulting from bubble formation, and internal circulation. And the Brownian motion is the least important. This theoretical analysis explains the

  12. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Directory of Open Access Journals (Sweden)

    Balicki Adrian

    2014-06-01

    Full Text Available Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of ‘zeroemission’ technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  13. Combustion characteristics of natural gas-hydrogen hybrid fuel turbulent diffusion flame

    Energy Technology Data Exchange (ETDEWEB)

    El-Ghafour, S.A.A.; El-dein, A.H.E.; Aref, A.A.R. [Mechanical Power Engineering Department, Faculty of Engineering, Suez Canal University, Port-Said (Egypt)

    2010-03-15

    Combustion characteristics of natural gas - hydrogen hybrid fuel were investigated experimentally in a free jet turbulent diffusion flame flowing into a slow co-flowing air stream. Experiments were carried out at a constant jet exit Reynolds number of 4000 and with a wide range of NG-H{sub 2} mixture concentrations, varied from 100%NG to 50%NG-50% H{sub 2} by volume. The effect of hydrogen addition on flame stability, flame length, flame structure, exhaust species concentration and pollutant emissions was conducted. Results showed that, hydrogen addition sustains a progressive improvement in flame stability and reduction in flame length, especially for relatively high hydrogen concentrations. Hydrogen-enriched flames found to have a higher combustion temperatures and reactivity than natural gas flame. Also, it was found that hydrogen addition to natural gas is an ineffective strategy for NO and CO reduction in the studied range, while a significant reduction in the %CO{sub 2} molar concentration by about 30% was achieved. (author)

  14. Thermogravimetric Analysis of Effects of High-Content Limstone Addition on Combustion Characteristics of Taixi Anthracite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; LI Mei; SUN Min; WEI Xian-yong

    2004-01-01

    Combustion characteristics of Taixi anthracite admixed with high content of limestone addition were investigated with thermogravimetric analysis. The results show that limestone addition has a little promoting effect on the ignition of raw coals as a whole. The addition of limestone is found to significantly accelerate the combustion and burnout of raw coals. The higher the sample mass is, the more significant the effect will be. The results also show that the change of limestone proportion between 45%-80% has little effect on ignition temperatures of coal in the blended samples. Increasing limestone content lowers the temperature corresponding to the maximum weight loss. Although higher maximum mass loss rates are observed with higher limestone content, the effect is found not ascribed to changing limestone addition, but to the decrease of absolute coal mass in the sample. The change of limestone proportion has little effect on its burnout temperature. Mechanism analysis indicates that these phenomena result mainly from improved heat conduction due to limestone addition.

  15. COMBUSTION CHARACTERISTICS OF CI ENGINE USING KARANJA BIODIESEL BLENDS AS FUEL

    Directory of Open Access Journals (Sweden)

    H.A. PHADTARE

    2013-05-01

    Full Text Available Karanja based bio-diesel is a non-edible, biodegradable fuel suitable for diesel engines. Karanja biodiesel has been prepared by transesterification method. Biodiesel-diesel blends have been prepared on volume basis. Physical properties of Karanja biodiesel, diesel and its blends have been determined. An experimentalinvestigation has been carried out to analyze combustion characteristics of a single cylinder, VCR diesel engine fuelled with Karanja biodiesel and its blends (10%, 20%, 30%, 50% and 75% with neat diesel. A series of engine tests, with CR 16.5, 17.5 and 18.5 have been conducted using each of the above blends for comparativeevaluation. Combustion parameters such as ignition delay, peak pressure development, heat release rate analysis of engine have been studied. The results of the experiment in each case have been compared with baseline data of neat diesel. Ignition delays of bio-diesel blends are lower than that of diesel; peak pressure takes place definitely after TDC for safe and efficient operation. Comparable rate of pressure rise obtained is indicative of stable and noise free operation of CI engines with karanja biodiesel blends. B10 is suitable alternative fuel for diesel at slightly higher CR can be used without any engine modifications.

  16. Influence of oxidant and fuel on the powder characteristics of LiNbO$_3$ synthesized by combustion method

    Indian Academy of Sciences (India)

    D H PIVA; H BIZ; R H PIVA; M R MORELLI

    2017-02-01

    Lithium niobate (LiNbO$_3$) is widely recognized as a promising material for replacing lead-based piezoelectric ceramics. Although the LiNbO3 synthesis by combustion method has been investigated with particular attention recently, the influence of oxidants and different fuels’ sources on the synthesized powders has not yet been thoroughly studied. In this work we investigate the influence of urea and maleic hydrazide as fuels and ammonium nitrate as an oxidant on the powder characteristics of LiNbO$_3$ synthesized by combustion method. In addition, powder characteristics and sinterability of powders prepared by combustion method are compared with those of powders prepared by solid-state reaction. The results show that the second phase LiNb$_3$O$_8$ was detected only when an oxidant agent was used in the synthesis process. Among all combustion reactions, the powders prepared with excess of urea presented better final characteristics. As a result, the sintering temperature for LiNbO$_3$ powders prepared by combustion method was appreciably lowered when compared with those prepared by solid-state reaction.

  17. Combustion Characteristics of a Diesel Engine Using Propanol Diesel Fuel Blends

    Science.gov (United States)

    Muthaiyan, Pugazhvadivu; Gomathinayagam, Sankaranarayanan

    2016-07-01

    The objective of the work is to study the use of propanol diesel blends as alternative fuel in a single cylinder diesel engine. In this work, four different propanol diesel blends containing 10, 15, 20 and 25 % propanol in diesel by volume were used as fuels. Load tests were conducted on the diesel engine and the combustion parameters such as cylinder gas pressure, ignition delay, rate of heat release and rate of pressure rise were investigated. The engine performance and emission characteristics were also studied. The propanol diesel blends showed longer ignition delay, higher rates of heat release and pressure rise. The thermal efficiency of the engine decreased marginally with the use of fuel blends. The propanol diesel blends decreased the CO, NOX and smoke emissions of the engine considerably.

  18. Novel analytical model for predicting the combustion characteristics of premixed flame propagation in lycopodium dust particles

    Energy Technology Data Exchange (ETDEWEB)

    Bidabadi, Mehdi; Rahbari, Alireza [Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

    2009-09-15

    This paper presents the effects of the temperature difference between gas and particle, different Lewis numbers, and heat loss from the walls in the structure of premixed flames propagation in a combustible system containing uniformly distributed volatile fuel particles in an oxidizing gas mixture. It is assumed that the fuel particles vaporize first to yield a gaseous fuel, which is oxidized in a gas phase. The analysis is performed in the asymptotic limit, where the value of the characteristic Zeldovich number is large. The structure of the flame is composed of a preheat zone, reaction zone, and convection zone. The governing equations and required boundary conditions are applied in each zone, and an analytical method is used for solving these equations. The obtained results illustrate the effects of the above parameters on the variations of the dimensionless temperature, particle mass friction, flame temperature, and burning velocity for gas and particle

  19. COMBUSTION CHARACTERISTICS OF DIESEL ENGINE OPERATING ON JATROPHA OIL METHYL ESTER

    Directory of Open Access Journals (Sweden)

    Doddayaraganalu Amasegoda Dhananjaya

    2010-01-01

    Full Text Available Fuel crisis because of dramatic increase in vehicular population and environmental concerns have renewed interest of scientific community to look for alternative fuels of bio-origin such as vegetable oils. Vegetable oils can be produced from forests, vegetable oil crops, and oil bearing biomass materials. Non-edible vegetable oils such as jatropha oil, linseed oil, mahua oil, rice bran oil, karanji oil, etc., are potentially effective diesel substitute. Vegetable oils have reasonable energy content. Biodiesel can be used in its pure form or can be blended with diesel to form different blends. It can be used in diesel engines with very little or no engine modifications. This is because it has combustion characteristics similar to petroleum diesel. The current paper reports a study carried out to investigate the combustion, performance and emission characteristics of jatropha oil methyl ester and its blend B20 (80% petroleum diesel and 20% jatropha oil methyl ester and diesel fuel on a single-cylinder, four-stroke, direct injections, water cooled diesel engine. This study gives the comparative measures of brake thermal efficiency, brake specific energy consumption, smoke opacity, HC, NOx, ignition delay, cylinder peak pressure, and peak heat release rates. The engine performance in terms of higher thermal efficiency and lower emissions of blend B20 fuel operation was observed and compared with jatropha oil methyl ester and petroleum diesel fuel for injection timing of 20° bTDC, 23° bTDC and 26° bTDC at injection opening pressure of 220 bar.

  20. Characteristics of ash and particle emissions during bubbling fluidised bed combustion of three types of residual forest biomass.

    Science.gov (United States)

    Ribeiro, João Peres; Vicente, Estela Domingos; Alves, Célia; Querol, Xavier; Amato, Fulvio; Tarelho, Luís A C

    2017-04-01

    Combustion of residual forest biomass (RFB) derived from eucalypt (Eucalyptus globulus), pine (Pinus pinaster) and golden wattle (Acacia longifolia) was evaluated in a pilot-scale bubbling fluidised bed reactor (BFBR). During the combustion experiments, monitoring of temperature, pressure and exhaust gas composition has been made. Ash samples were collected at several locations along the furnace and flue gas treatment devices (cyclone and bag filter) after each combustion experiment and were analysed for their unburnt carbon content and chemical composition. Total suspended particles (TSP) in the combustion flue gas were evaluated at the inlet and outlet of cyclone and baghouse filter and further analysed for organic and elemental carbon, carbonates and 57 chemical elements. High particulate matter collection efficiencies in the range of 94-99% were observed for the baghouse, while removal rates of only 1.4-17% were registered for the cyclone. Due to the sand bed, Si was the major element in bottom ashes. Fly ashes, in particular those from eucalypt combustion, were especially rich in CaO, followed by relevant amounts of SiO2, MgO and K2O. Ash characteristics varied among experiments, showing that their inorganic composition strongly depends on both the biomass composition and combustion conditions. Inorganic constituents accounted for TSP mass fractions up to 40 wt%. Elemental carbon, organic matter and carbonates contributed to TSP mass fractions in the ranges 0.58-44%, 0.79-78% and 0.01-1.7%, respectively.

  1. Altered combustion characteristics of metallized energetics due to stable secondary material inclusion

    Science.gov (United States)

    Terry, Brandon C.

    Though metals and metalloids have been widely considered as reactive fuels, the ability to tune their ignition and combustion characteristics remains challenging. One means to accomplish this may be through low-level inclusion of secondary materials into the metallized fuel. While there are several potential methods to stably introduce secondary inclusion materials, this work focuses on the use of mechanical activation (MA) and metal alloys. Recent work has shown that low-level inclusion of fluoropolymers into aluminum particles can have a substantial effect on their combustion characteristics. The reflected shock ignition of mechanically activated aluminum/polytetrafluoroethylene (MA Al/PTFE) is compared to a physical mixture (PM) of Al/PTFE, neat spherical aluminum, and flake aluminum. It was found that the powders with higher specific surface areas ignited faster than the spherical particles of the same size, and had ignition delay times comparable to agglomerates of aluminum particles that were two orders of magnitude smaller in size. Flake aluminum powder had the same ignition delay as MA Al/PTFE, indicating that any initial aluminum/fluoropolymer reactions did not yield an earlier onset of aluminum oxidation. However, MA Al/PTFE did have a shorter total burn time. The PM of Al/PTFE powder had a shorter ignition delay than neat spherical aluminum due to the rapid decomposition of PTFE into reactive fluorocarbon compounds, but the subsequent fluorocarbon reactions also created a secondary luminosity profile that significantly increased the total burn time of the system. The explosive shock ignition of aluminum and aluminum-silicon eutectic alloy compacts was evaluated with and without polymer inclusions. A statistical analysis was completed, investigating the effects of: detonation train orientation (into or not into a hard surface); the high explosive driver; whether the metal/polymer system is mechanically activated; particle size; particle morphology

  2. Lean homogenous combustion of E-diesel using external mixture formation technique

    Directory of Open Access Journals (Sweden)

    A. Avinash

    2015-09-01

    Full Text Available For the past one hundred years, lots of easily accessible petroleum fuel has been burned out by humankind in inefficient engines. In this regard, present-day engine researchers face a formidable challenge to achieve the goal of significant improvements in both thermal efficiency and fuel economy. Although the direction to reach this target is critical, homogenous charge compression ignition (HCCI is just another combustion concept to achieve this target. By the way, this work investigates the combustion phenomena of the HCCI engine by external mixture formation technique. In a nut-shell, an endeavor has been made in this work to prepare homogeneous mixture outside the combustion chamber using a fuel vaporizer system to form a uniform fuel–air mixture. The fundamental research experiments were carried out with vaporized diesel and vaporized e-diesel blends (10% and 20% ethanol substitution by volume, and the results were compared with conventional diesel engine operation. In HCCI mode, the maximum rate of pressure rises and the maximum rate of heat-release significantly reduced with increase of ethanol concentration in diesel. The experimental outcomes exposed that when HCCI engine is operated with e-diesel blend, smooth engine operation is apparent.

  3. Experimental investigation of CAI combustion in a two-stroke poppet valve DI engine

    OpenAIRE

    Zhang, Yan

    2015-01-01

    This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London Due to their ability to simultaneously reduce fuel consumption and NOx emissions, Controlled Auto Ignition (CAI) and HCCI combustion processes have been extensively researched over the last decade and adopted on prototype gasoline engines. These combustion processes were initially achieved on conventional two-stroke ported gasoline engines, but there have been significantly fewer stu...

  4. Simulation Study on Combustion Characteristic and Emissions of Natural Gas HCCI Engine%天然气HCCI发动机燃烧特性和排放物的数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    回胜; 孙锐

    2014-01-01

    本文分析利用CHEMKIN软件中的零维单区HCCI模型模拟了不同的边界参数包括:压缩比、进气温度、进气压力和转速对天然气HCCI发动机燃烧特性及排放物的影响.利用模拟的结果分析了边界参数的变化对发动机缸内温度、压力、着火时刻和污染物排放的影响,为合理选择天然气HCCI发动机的边界参数提供了参考.

  5. Large-eddy Simulation on Combustion Characteristics of Isooctane HCCI Engine%异辛烷HCCI发动机燃烧特性的大涡数值模拟

    Institute of Scientific and Technical Information of China (English)

    曾文; 宋崇林

    2009-01-01

    通过修改发动机多维CFD计算程序KIVA-3V,并与化学动力学程序CHEMKIN Ⅲ相耦合,建立了异辛烷HCCI发动机燃烧过程的大涡模拟(LES)计算模型.利用此模型对异辛烷HCCI发动机的燃烧特性进行了详细分析.发动机以异辛烷为燃料,其化学反应采用了详细的动力学机理.结果表明:大涡模拟所得到的缸内压力变化趋势与试验基本吻合;采用LES模型计算时,缸内混合气燃烧区域以柱形向四周扩散,而采用k-ε模型计算时以球形向四周扩散.

  6. Investigation on thermal and trace element characteristics during co-combustion biomass with coal gangue.

    Science.gov (United States)

    Zhou, Chuncai; Liu, Guijian; Fang, Ting; Lam, Paul Kwan Sing

    2015-01-01

    The thermochemical behaviors during co-combustion of coal gangue (CG), soybean stalk (SS), sawdust (SD) and their blends prepared at different ratios have been determined via thermogravimetric analysis. The simulate experiments in a fixed bed reactor were performed to investigate the partition behaviors of trace elements during co-combustion. The combustion profiles of biomass was more complicated than that of coal gangue. Ignition property and thermal reactivity of coal gangue could be enhanced by the addition of biomass. No interactions were observed between coal gangue and biomass during co-combustion. The volatilization ratios of trace elements decrease with the increasing proportions of biomass in the blends during co-combustion. Based on the results of heating value, activation energy, base/acid ratio and gaseous pollutant emissions, the blending ratio of 20-30% biomass content is regarded as optimum composition for blending and could be applied directly at current combustion application with few modifications.

  7. Characteristics variation of coal combustion residues in an Indian ash pond.

    Science.gov (United States)

    Asokan, Pappu; Saxena, Mohini; Aparna, Asokan; Asolekar, Shyam R; Asoletar, Shyam R

    2004-08-01

    Coal-fired power plants all over the world are cited as one of the major sources that generate huge quantities of coal combustion residues (CCRs) as solid wastes. Most frequently CCRs are collected through electrostatic precipitators, mixed with bottom ash by hydraulic systems and deposited in ash ponds. The quality of the CCRs at different locations in one of the ash ponds in Central India was evaluated to understand the variation in characteristics with a view to effective utilization. Results revealed that the presence of fine particles (distance from the ash slurry inlet zone in the ash pond. Wide variations in the bulk density (800-980 kg m(-3)), porosity (45-57%) and water-holding capacity (57.5-75.7%) of CCRs were recorded. With increasing distance the pH of the CCRs decreased (from 9.0 to 8.2) and electrical conductivity increased (from 0.25 to 0.65 dS m(-3)). The presence of almost all the heavy metals in CCRs exhibited an increase with distance from the ash slurry discharge zone due to the increase in surface area (from 0.1038 to 2.3076 m2 g(-1)) of CCRs particles. The present paper describes the variation of characteristics of CCRs deposited in the ash pond and their potential applications.

  8. Physical and Combustion Characteristics of Briquettes Made from Water Hyacinth and Phytoplankton Scum as Binder

    Directory of Open Access Journals (Sweden)

    R. M. Davies

    2013-01-01

    Full Text Available The study investigated the potential of water hyacinths and phytoplankton scum, an aquatic weed, as binder for production of fuel briquettes. It also evaluated some physical and combustion characteristics. The water hyacinths were manually harvested, cleaned, sun-dried, and milled to particle sizes distribution ranging from <0.25 to 4.75 mm using hammer mill. The water hyacinth grinds and binder (phytoplankton scum at 10% (B1, 20% (B2, 30% (B3, 40% (B4, and 50% (B5 by weight of each feedstock were fed into a steel cylindrical die of dimension 14.3 cm height and 4.7 cm diameter and compressed by hydraulic press at pressure 20 MPa with dwell time of 45 seconds. Data were analysed using analysis of variance and descriptive statistics. Initial bulk density of uncompressed mixture of water hyacinth and phytoplankton scum at different binder levels varied between 113.86 ± 3.75 (B1 and 156.93 ± 4.82 kg/m3 (B5. Compressed and relaxed densities of water hyacinth briquettes at different binder proportions showed significant difference . Durability of the briquettes improved with increased binder proportion. Phytoplankton scum improved the mechanical handling characteristics of the briquettes. It could be concluded that production of water hyacinth briquettes is feasible, cheaper, and environmentally friendly and that they compete favourably with other agricultural products.

  9. On-Board Engine Exhaust Particulate Matter Sensor for HCCI and Conventional Diesel Engines

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Matt; Matthews, Ron

    2011-09-30

    The goal of the research was to refine and complete development of an on-board particulate matter (PM) sensor for diesel, DISI, and HCCI engines, bringing it to a point where it could be commercialized and marketed.

  10. Effect of ignition timing and hydrogen fraction on combustion and emission characteristics of natural gas direct-injection engine

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An experimental study on the combustion and emission characteristics of a direct-injection spark-ignited engine fueled with natural gas/hydrogen blends under various ignition timings was conducted.The results show that ignition timing has a significant influence on engine performance,combustion and emissions.The interval between the end of fuel injection and ignition timing is a very important parameter for direct-injection natural gas engines.The turbulent flow in the combustion chamber generated by the fuel jet remains high and relative strong mixture stratification is introduced when decreasing the angle interval between the end of fuel injection and ignition timing giving fast burning rates and high thermal efficiencies.The maximum cylinder gas pressure,maximum mean gas temperature,maximum rate of pressure rise and maximum heat release rate increase with the advancing of ignition timing.However,these parameters do not vary much with hydrogen addition under specific ignition timing indicating that a small hydrogen fraction addition of less than 20% in the present experiment has little influence on combustion parameters under specific ignition timing.The exhaust HC emission decreases while the exhaust CO2 concentration increases with the advancing of ignition timing.In the lean combustion condition,the exhaust CO does not vary much with ignition timing.At the same ignition timing,the exhaust HC decreases with hydrogen addition while the exhaust CO and CO2 do not vary much with hydrogen addition.The exhaust NOx increases with the advancing of' ignition timing and the behavior tends to be more obvious at large ignition advance angle.The brake mean effective pressure and the effective thermal efficiency of natural gas/hydrogen mixture combustion increase compared with those of natural gas combustion when the hydrogen fraction is over 10%.

  11. The influence of charge stratification on the spectral signature of partially premixed combustion in a light-duty optical engine

    KAUST Repository

    Najafabadi, M. Izadi

    2017-03-25

    The origin of light emission during low-temperature combustion in a light-duty IC engine is investigated by high-speed spectroscopy in both HCCI and PPC regimes. Chemiluminescence and thermal radiation are expected to be the dominant sources of light emission during combustion. A method has been developed to distinguish chemiluminescence from thermal radiation, and different chemiluminescing species could be identified. Different combustion modes and global equivalence ratios are analyzed in this manner. The results indicate that the spectral signature (270–540 nm range) of the combustion is highly dependent on the stratification level. A significant broadband chemiluminescence signal is detected and superimposed on all spectra. This broadband chemiluminescence signal can reach up to 100 percent of the total signal in HCCI combustion, while it drops to around 80 percent for stratified combustion (PPC). We show that this broadband signal can be used as a measure for the heat release rate. The broadband chemiluminescence did also correlate with the equivalence ratio quite well in both HCCI and PPC regimes, suggesting that the total emission in the spectral region of 330–400 nm can serve as a proxy of equivalence ratio and the rate of heat release. Regarding C2* chemiluminescence, we see two different chemical mechanisms for formation of C2* in the PPC regime: first during the early stage of combustion by the breakup of bigger molecules and the second during the late stage of combustion when soot particles are forming.

  12. The influence of charge stratification on the spectral signature of partially premixed combustion in a light-duty optical engine

    Science.gov (United States)

    Najafabadi, M. Izadi; Egelmeers, Luc; Somers, Bart; Deen, Niels; Johansson, Bengt; Dam, Nico

    2017-04-01

    The origin of light emission during low-temperature combustion in a light-duty IC engine is investigated by high-speed spectroscopy in both HCCI and PPC regimes. Chemiluminescence and thermal radiation are expected to be the dominant sources of light emission during combustion. A method has been developed to distinguish chemiluminescence from thermal radiation, and different chemiluminescing species could be identified. Different combustion modes and global equivalence ratios are analyzed in this manner. The results indicate that the spectral signature (270-540 nm range) of the combustion is highly dependent on the stratification level. A significant broadband chemiluminescence signal is detected and superimposed on all spectra. This broadband chemiluminescence signal can reach up to 100 percent of the total signal in HCCI combustion, while it drops to around 80 percent for stratified combustion (PPC). We show that this broadband signal can be used as a measure for the heat release rate. The broadband chemiluminescence did also correlate with the equivalence ratio quite well in both HCCI and PPC regimes, suggesting that the total emission in the spectral region of 330-400 nm can serve as a proxy of equivalence ratio and the rate of heat release. Regarding C2* chemiluminescence, we see two different chemical mechanisms for formation of C2* in the PPC regime: first during the early stage of combustion by the breakup of bigger molecules and the second during the late stage of combustion when soot particles are forming.

  13. A six-zone simulation model for HCCI engines with a non-segregated solver of zone state

    Science.gov (United States)

    Kozarac, Darko; Lulic, Zoran; Sagi, Goran

    2010-07-01

    A new six-zone simulation model for the calculation of changes in an HCCI engine has been developed and tested. The model uses comprehensive chemical kinetics and a non-sequential solver of zone states. This means that the state vector comprises the states in all zones, and that the changes in states in all zones are calculated simultaneously. In this manner, physical accuracy during the calculation of a new state is maintained at the expense of the calculation time. The model comprises the wall heat transfer, zone heat transfer and zone mass transfer as means of zone interactions. The cylinder is divided into two central zones, three boundary layer zones and one crevice zone. Since the model calculates only the high pressure part of an engine cycle, it has been connected with the cycle simulation software AVL Boost. In this way, a relatively easy-to-use, higher accuracy, simulation tool for HCCI engines has been obtained. The model was tested by comparing simulation results with experimental ones. The comparison was made with a single cylinder engine running on isooctane. The calculated pressure and net rate of heat release correspond to the experimental results very well in the entire operating region. By using the six-zone simulation model, a big improvement, compared to the single zone simulation, is obtained in operating points where combustion efficiency is over 90%. Results of emissions of unburned HC and CO show that predictions of these species are greatly improved, but it has also been noticed that these emissions are still slightly underpredicted. Predictions of emissions that come from crevice regions are good, but emissions that come from the corners of boundary layers are not captured very well. A detailed description of the simulation model is given, and validation results and possibilities of a further development are discussed.

  14. Research on Spray, Combustion and Emission Characteristics for DI Diesel Engine

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To improve the combustion chamber shape that can decrease the directed injection (DI) diesel emission, the theories of DI diesel spray, combustion and pollutant formation model are analysed and implemented based on the CFD code FIRE. Results show that the chamber with contracting orifice can get stronger squish swirl intensity. The results of the verification studies show a good accordance with the measurements and reveal that the individual processes of spray evolution, combustion and pollutant formation are well captured in FIRE. Finally, based on the analyzing and comparing of the calculation results of different chambers, a combustion chamber of contracting orifice geometry with lower emission is proposed.

  15. A kinetic study on pyrolysis and combustion characteristics of oil cakes:Effect of cellulose and lignin content

    Institute of Scientific and Technical Information of China (English)

    Ramakrishna Gottipati; Susmita Mishra

    2011-01-01

    Pyrolysis and combustion characteristics of three different oil cakes such as Pongamia ( Pongamia Pinnata), Madhuca (Madhuca Indica), and Jatropha (Jatropha curcas) were investigated in this study.The cellulose and lignin contents of oil cakes play very important role in pyrolysis and combustion processes.A kinetic investigation of three oil cakes was carried out and major part of the samples decomposed between 210 ℃ and 500 ℃.Pyrolysis and combustion were carried out with the mixtures of cellulose and lignin chemicals in different ratios and compared with the oil cakes.The biomass with higher cellulose content showed faster rate of pyrolysis than the biomass with higher lignin content.However at higher temperatures ( >600 ℃ ) all the oil cakes exhibited similar conversion at low heating rate in N2 atmosphere.Apparent activation energies increased for Madhuca and Pongamia oil cakes indicating the presence of more cellulose whereas, low activation energy of Jatropha confirms more lignin content.

  16. Influence of low-temperature combustion and dimethyl ether-diesel blends on performance, combustion, and emission characteristics of common rail diesel engine: a CFD study.

    Science.gov (United States)

    Lamani, Venkatesh Tavareppa; Yadav, Ajay Kumar; Narayanappa, Kumar Gottekere

    2017-06-01

    Due to presence of more oxygen, absence of carbon-carbon (C-C) bond in chemical structure, and high cetane number of dimethyl ether (DME), pollution from DME operated engine is less compared to diesel engine. Hence, the DME can be a promising alternative fuel for diesel engine. The present study emphasizes the effect of various exhaust gas recirculation (EGR) rates (0-20%) and DME/Diesel blends (0-20%) on combustion characteristics and exhaust emissions of common rail direct injection (CRDI) engine using three-dimensional computational fluid dynamics (CFD) simulation. Extended coherent flame model-3 zone (ECFM-3Z) is implemented to carry out combustion analysis, and k-ξ-f model is employed for turbulence modeling. Results show that in-cylinder pressure marginally decreases with employing EGR compared to without EGR case. As EGR rate increases, nitrogen oxide (NO) formation decreases, whereas soot increases marginally. Due to better combustion characteristics of DME, indicated thermal efficiency (ITE) increases with the increases in DME/diesel blend ratio. Adverse effect of EGR on efficiency for blends is less compared to neat diesel, because the anoxygenated region created due to EGR is compensated by extra oxygen present in DME. The trade-off among NO, soot, carbon monoxide (CO) formation, and efficiency is studied by normalizing the parameters. Optimum operating condition is found at 10% EGR rate and 20% DME/diesel blend. The maximum indicated thermal efficiency was observed for DME/diesel ratio of 20% in the present range of study. Obtained results are validated with published experimental data and found good agreement.

  17. Flow field characteristics analysis and combustion modes classification for a strut/cavity dual-mode combustor

    Science.gov (United States)

    Zhang, Chenlin; Chang, Juntao; Zhang, Yuanshi; Wang, Youyin; Bao, Wen

    2017-08-01

    Experimental and numerical study of a strut/cavity dual-mode combustor has been conducted in this paper. Under different fuel equivalence ratio and allocation proportion conditions, the pressure distribution and flow field structure of combustor show distinct characteristics. For strut fuel injecting at a low equivalence ratio, the luminosity images show that combustion zone distributes in the shear layer behind the strut. The wall fuel injecting before strut would change the starting point of pressure rising. Based on the flow field structure, the dual-mode combustor operation process is classified into three combustion modes, including scramjet mode, weak ramjet mode and strong ramjet mode. Because of a strong interaction of the shock wave with the boundary layer, weak ramjet mode has a stronger isolator compression effect and higher combustion efficiency than scramjet mode. With heat release increasing, the thermal throat formation is an indication of the strong ramjet mode, which has a subsonic gap in the isolator. Further, by judging the pressure from dominant pressure sensor before the strut, the three different combustion modes could be classified. Comparing the specific impulse of combustor, it has an obvious distinction in the different combustion modes.

  18. Theoretical modeling of combustion characteristics and performance parameters of biodiesel in DI diesel engine with variable compression ratio

    Directory of Open Access Journals (Sweden)

    Mohamed F. Al-Dawody, S. K. Bhatti

    2013-01-01

    Full Text Available Increasing of costly and depleting fossil fuels are prompting researchers to use edible as well as non-edible vegetable oils as a promising alternative to petro-diesel fuels. A comprehensive computer code using ”Quick basic” language was developed for the diesel engine cycle to study the combustion and performance characteristics of a single cylinder, four stroke, direct injection diesel engine with variable compression ratio. The engine operates on diesel fuel and 20% (mass basis of biodiesel (derived from soybean oil blended with diesel. Combustion characteristics such as cylinder pressure, heat release fraction, heat transfer and performance characteristics such as brake power; and brake specific fuel consumption (BSFC were analyzed. On the basis of the first law of thermodynamics the properties at each degree crank angle was calculated. Wiebe function is used to calculate the instantaneous heat release rate. The computed results are validated through the results obtained in the simulation Diesel-rk software.

  19. Theoretical modeling of combustion characteristics and performance parameters of biodiesel in DI diesel engine with variable compression ratio

    Energy Technology Data Exchange (ETDEWEB)

    Al-Dawody, Mohamed F.; Bhatti, S.K. [Department of Mechanical Engineering, Andhra University (India)

    2013-07-01

    Increasing of costly and depleting fossil fuels are prompting researchers to use edible as well as non-edible vegetable oils as a promising alternative to petro-diesel fuels. A comprehensive computer code using ''Quick basic'' language was developed for the diesel engine cycle to study the combustion and performance characteristics of a single cylinder, four stroke, direct injection diesel engine with variable compression ratio. The engine operates on diesel fuel and 20% (mass basis) of biodiesel (derived from soybean oil) blended with diesel. Combustion characteristics such as cylinder pressure, heat release fraction, heat transfer and performance characteristics such as brake power; and brake specific fuel consumption (BSFC) were analyzed. On the basis of the first law of thermodynamics the properties at each degree crank angle was calculated. Wiebe function is used to calculate the instantaneous heat release rate. The computed results are validated through the results obtained in the simulation Diesel-rk software.

  20. Effects of oxygen enriched combustion on pollution and performance characteristics of a diesel engine

    Directory of Open Access Journals (Sweden)

    P. Baskar

    2016-03-01

    Full Text Available Oxygen enriched combustion is one of the attractive combustion technologies to control pollution and improve combustion in diesel engines. An experimental test was conducted on a single cylinder direct injection diesel engine to study the impact of oxygen enrichment on pollution and performance parameters by increasing the oxygen concentration of intake air from 21 to 27% by volume. The tests results show that the combustion process was improved as there is an increase in thermal efficiency of 4 to 8 percent and decrease in brake specific fuel consumption of 5 to 12 percent. There is also a substantial decrease in unburned hydro carbon, carbon mono-oxide and smoke density levels to the maximum of 40, 55 and 60 percent respectively. However, there is a considerable increase in nitrogen oxide emissions due to increased combustion temperature and extra oxygen available which needs to be addressed.

  1. A Study of Thermal Analyses and Fundamental Combustion Characteristics for Thermal Utility with Biomass Volatile Matter

    Science.gov (United States)

    Ida, Tamio; Namba, Kunihiko; Sano, Hiroshi

    Based on un-use biomass utilities, Carbonized technology is noticed as material utilities and solid fuel. Therefore, this technology is tackling by national project as large-scale utilities. But, this technology is dehydrated volatiles matter during carbonized from biomass. Especially, Woody tar into one of volatile matter has vicious handling to get into trouble in carbonized equipment. In this study, we propose to get fundamental knowledge for effective thermal utility through thermal decompositions and fundamental combustion properties on experimental results. Woody tar has high caloric value (approximately 30MJ/kg) and high carbon ration. On the other hand, a woody vinegar liquid has thermal decomposition property close to water property with heat absorption as evaporation latent heat of water. In fundamental combustion experimental result, a woody tar has fl ammable combustion and surface combustion. Especially, a total combustion and ignition time properties has hyperbola relation to environment temperatures in furnace.

  2. Variation of diesel soot characteristics by different types and blends of biodiesel in a laboratory combustion chamber.

    Science.gov (United States)

    Omidvarborna, Hamid; Kumar, Ashok; Kim, Dong-Shik

    2016-02-15

    Very little information is available on the physical and chemical properties of soot particles produced in the combustion of different types and blends of biodiesel fuels. A variety of feedstock can be used to produce biodiesel, and it is necessary to better understand the effects of feedstock-specific characteristics on soot particle emissions. Characteristics of soot particles, collected from a laboratory combustion chamber, are investigated from the blends of ultra-low sulfur diesel (ULSD) and biodiesel with various proportions. Biodiesel samples were derived from three different feedstocks, soybean methyl ester (SME), tallow oil (TO), and waste cooking oil (WCO). Experimental results showed a significant reduction in soot particle emissions when using biodiesel compared with ULSD. For the pure biodiesel, no soot particles were observed from the combustion regardless of their feedstock origins. The overall morphology of soot particles showed that the average diameter of ULSD soot particles is greater than the average soot particles from the biodiesel blends. Transmission electron microscopy (TEM) images of oxidized soot particles are presented to investigate how the addition of biodiesel fuels may affect structures of soot particles. In addition, inductively coupled plasma mass spectrometry (ICP-MS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were conducted for characterization of soot particles. Unsaturated methyl esters and high oxygen content of biodiesel are thought to be the major factors that help reduce the formation of soot particles in a laboratory combustion chamber. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Bifurcation characteristics of coal spontaneous combustion and analysis of critical state of gaseous reaction in a packed bed

    Institute of Scientific and Technical Information of China (English)

    LIANG Yun-tao; JIA Bao-shan; CHEN Jing

    2008-01-01

    The numerical model was presented for the coal combustion in the packed bed.The bifurcation characteristic of the ignition-extinction of solid-phase smoldering and transition to flaming was studied for the packed bed of coal. One of the Frank-Kamenetskii parameter β1 was selected as the control parameter. The computed results show that the bifurcation curve is obviously divided into two zones of solid-phase reaction and gasphase reaction, and the total process of ignition-extinction presents twice bifurcation characteristic. Moreover, the vanishing of critical state of ignition-extinction is studied. One of the transition points, ε2=0.05, is numerically solved for the vanishing of critical state. The larger the value of ε2 is, the easier the gas-phase can react. However, the combustion temperature will decrease with increasing ε2. The other transition point α2=0.53 is also obtained. With increasing the value of α2, the combustion temperature of gas-phase reaction is close to the smoldering temperature of coal. When α2 is infinite, the only reaction occurring is the smoldering combustion of solid-phase, and the gas-phase cannot react.

  4. Pollutant emission characteristics of rice husk combustion in a vortexing fluidized bed incinerator

    Institute of Scientific and Technical Information of China (English)

    Feng Duan; Chiensong Chyang; Yucheng Chin; Jim Tso

    2013-01-01

    Rice husk with high volatile content was burned in a pilot scale vortexing fiuidized bed incinerator.The fluidized bed incinerator was constructed of 6 mm stainless steel with 0.45 m in diameter and 5 m in height.The emission characteristics of CO,NO,and SO2 were studied.The effects of operating parameters,such as primary air flow rate,secondary air flow rate,and excess air ratio on the pollutant emissions were also investigated.The results show that a large proportion of combustion occurs at the bed surface and the freeboard zone.The SO2 concentration in the flue gas decreases with increasing excess air ratio,while the NOx concentration shows reverse trend.The flow rate of secondary air has a significant impact on the CO emission.For a fixed primary air flowrate,CO emission decreases with the secondary air flowrate.For a fixed excess air ratio,CO emission decreases with the ratio of secondary to primary air flow.The minimum CO emission of 72 ppm is attained at the operating condition of 40% excess air ratio and 0.6 partition air ratio.The NOx and SO2 concentrations in the flue gas at this condition are 159 and 36 ppm,which conform to the EPA regulation of Taiwan.

  5. Ignition and Combustion Characteristics of Pure Bulk Metals: Normal-Gravity Test Results

    Science.gov (United States)

    Abbud-Madrid, A.; Fiechtner, G. J.; Branch, M. C.; Daily, J. W.

    1994-01-01

    An experimental apparatus has been designed for the study of bulk metal ignition under elevated, normal and reduced gravity environments. The present work describes the technical characteristics of the system, the analytical techniques employed, the results obtained from the ignition of a variety of metals subjected to normal gravity conditions and the first results obtained from experiments under elevated gravity. A 1000 W xenon short-arc lamp is used to irradiate the top surface of a cylindrical metal specimen 4 mm in diameter and 4 mm high in a quiescent pure-oxygen environment at 0.1 MPa. Iron, titanium, zirconium, magnesium, zinc, tin, and copper specimens are investigated. All these metals exhibit ignition and combustion behavior varying in strength and speed. Values of ignition temperatures below, above or in the range of the metal melting point are obtained from the temperature records. The emission spectra from the magnesium-oxygen gas-phase reaction reveals the dynamic evolution of the ignition event. Scanning electron microscope and x-ray spectroscopic analysis provide the sequence of oxide formation on the burning of copper samples. Preliminary results on the effect of higher-than-normal gravity levels on the ignition of titanium specimens is presented.

  6. Numerical simulation of coupled fluid flow and heat transfer characteristics in a submerged combustion vaporizer

    Science.gov (United States)

    Han, Chang-Liang; Ren, Jing-Jie; Wang, Yan-Qing; Dong, Wen-Ping; Bi, Ming-Shu

    2016-12-01

    Submerged combustion vaporizer (SCV) has been widely employed in Liquefied Natural Gas (LNG) receiving terminals as the main peaking-shaving facility. In the current work, numerical simulation was carried out to study the intrinsic fluid flow and heat transfer characteristics inside the SCV. After the verification of the numerical model and method with the experimental data, detailed results about flow field and temperature field were presented to have an understanding of the principle of shell-side heat transfer enhancement. The distributions of local LNG temperature, wall temperature, water bath temperature and heat transfer coefficient along the tube length were also revealed. Moreover, the influences of main operating parameters such as flue gas temperature, inlet LNG velocity, inlet LNG pressure, static water height and flue gas flux on the system performance were systematically investigated. Finally, based on current simulation results, two empirical correlations were proposed to predict the coupled heat transfer performance of SCV. The simulated results could provide some insight into the design and optimization of SCV.

  7. Biodiesel Production from Selected Microalgae Strains and Determination of its Properties and Combustion Specific Characteristics

    Directory of Open Access Journals (Sweden)

    N. Kokkinos

    2015-11-01

    Full Text Available Biofuels are gaining importance as significant substitutes for the depleting fossil fuels. Recent focus is on microalgae as the third generation feedstock. In the present research work, two indigenous fresh water and two marine Chlorophyte strains have been cultivated successfully under laboratory conditions using commercial fertilizer (Nutrileaf 30-10-10, initial concentration=70 g/m3 as nutrient source. Gas chromatographic analysis data showed that microalgae biodiesel obtained from Chlorophyte strains biomass were composed of fatty acid methyl esters. The produced microalgae biodiesel achieved a range of 2.2 - 10.6 % total lipid content and an unsaturated FAME content between 49 mol% and 59 mol%. The iodine value, the cetane number, the cold filter plugging point, the oxidative stability as well as combustion specific characteristics of the final biodiesels were determined based on the compositions of the four microalgae strains. The calculated biodiesel properties compared then with the corresponding properties of biodiesel from known vegetable oils, from other algae strains and with the specifications in the EU (EN 14214 and US (ASTM D6751 standards. The derived biodiesels from indigenous Chlorophyte algae were significantly comparable in quality with other biodiesels.

  8. An Experimental Study of Emission and Combustion Characteristics of Marine Diesel Engine with Fuel Injector Malfunctions

    Directory of Open Access Journals (Sweden)

    Kowalski Jerzy

    2016-01-01

    Full Text Available The presented paper shows the results of the laboratory study on the relation between chosen malfunctions of a fuel injector and composition of exhaust gas from the marine engine. The object of research is a marine 3-cylinder, four-stroke, direct injection diesel engine with an intercooler system. The engine was loaded with a generator and supercharged. The generator was electrically connected to the water resistance. The engine operated with a load between 50 kW and 250 kW at a constant speed. The engine load and speed, parameters of the turbocharger, systems of cooling, fuelling, lubricating and air exchange, were measured. Fuel injection and combustion pressures in all cylinders of the engine were also recorded. Exhaust gas composition was recorded by using a electrochemical gas analyzer. Air pressure, temperature and humidity were also recorded. Emission characteristics of the engine were calculated according to ISO 8178 standard regulations. During the study the engine operated at the technical condition recognized as „working properly” and with simulated fuel injector malfunctions. Simulation of malfunctions consisted in the increasing and decreasing of fuel injector static opening pressure, decalibration of fuel injector holes and clogging 2 neighboring of 9 fuel injector holes on one of 3 engine cylinders.

  9. Combustion synthesis and luminescence characteristic of rare earth activated LiCaBO3

    Institute of Scientific and Technical Information of China (English)

    N.S. Bajaj; S.K. Omanwar

    2012-01-01

    Lithium calcium borate (LiCaBO3) polycrystalline thermoluminescence (TL) phosphor doped with rare earth (Tb3+ and Dy3+) elements was synthesized by novel solution combustion synthesis.The reaction produced very stable crystalline LiCaBO3:D (D=Tb3+ and Dy3+)phosphors.These rare earth doped phosphors material showed maximum TL sensitivity with favorable glow curve shape.TL glow curve of X-ray irradiated that LiCaBO3:Tb3+ and LiCaBO3:Dy3+ samples showed two major well-separated glow peaks.The TL sensitivity of these phosphors to X-ray radiation was comparable with that of TLD-100 (Harshaw).Photoluminescence spectra of LiCaBO3:Tb3+ and LiCaBO3:Dy3+ showed the characteristic Tb3+ and Dy3+ peaks respectively.TL response to X-ray radiation dose was linear up to 25 Gy.

  10. Effect of Metal Additives on the Combustion Characteristics of High-Energy Materials

    Directory of Open Access Journals (Sweden)

    Korotkikh Alexander

    2016-01-01

    Full Text Available Thermodynamic calculation of combustion parameters and equilibrium composition of HEMs combustion products showed, that at the increase of aluminum powder dispersity the specific impulse and combustion temperature of solid propellants are reduced due to the decrease of the mass fraction of active aluminum in particles. Partial or complete replacement of aluminum by metal powder (B, Mg, AlB2, Al\\Mg alloy, Fe, Ti and Zr in HEMs composition leads to the reduce of the specific impulse and combustion temperature. Replacement of aluminum powder by boron and magnesium in HEM reduces the mass fraction of condensed products in the combustion chamber of solid rocket motor. So, for compositions HEMs with boron and aluminum boride the mass fraction in chamber is reduced by 24 and 36 %, respectively, with respect to the composition HEMs with Al powder. But the mass fraction of CCPs in the nozzle exit increases by 13 % for HEMs with aluminum boride due to the formation of boron oxide in the condensed combustion products. Partial replacement of 2 wt. % aluminum powder by iron and copper additives in HEM leads to the reduce of CCPs mass fraction in chamber by 4–10 % depending on the aluminum powder dispersity duo to these metals are not formed condensed products at the HEMs combustion in chamber.

  11. Physical properties, evaporation and combustion characteristics of nanofluid-type fuels

    Science.gov (United States)

    Tanvir, Saad

    Nanofluids are liquids with stable suspension of nanoparticles. Limited studies in the past have shown that both energetic and catalytic nanoparticles once mixed with traditional liquid fuels can be advantageous in combustion applications, e.g., increased energy density and shortened ignition delay. Contradictions in existing literature, scarcity of experimental data and lack of understanding on how the added nanoparticles affect the physical properties as well as combustion characteristics of the resulting fuel motivated us to launch a detailed experimental and theoretical investigation. The surface tension of ethanol and n-decane based nanofluid fuels containing suspended nanoparticles were measured using the pendant drop method by solving the Young-Laplace equation. The results show that surface tension increases both with particle concentration (above a critical concentration) and particle size. This is because the Van der Waals forces between particles at the liquid/gas interface increases surface free energy that overcomes any electrostatic repulsion between the particles and increases surface tension. This present work also reports experimental analysis of the latent heat of vaporization ( Hfg) of nanofluids. Results show that the addition of Ag and Fe nanoparticles in water results is a substantial reduction in Hfg. On the contrary Al addition slightly increases Hfg. Similar observations are made for ethanol based nanofluids. Molecular dynamics simulations showed that the strength of bonding between particles and the fluid molecules is the governing factor in the variation of Hfg upon particle addition. The thermal conductivity was measured using KD2-Pro from Decagon Devices based on the transient line heat source method. The rheological properties of the ethanol and ethanol/nanoparticles suspensions are measured using a StresstechRTM rotational rheometer. Both properties increased with increasing particle concentration. Trends are found to be consistent

  12. A Review on Homogeneous Charge Compression Ignition and Low Temperature Combustion by Optical Diagnostics

    Directory of Open Access Journals (Sweden)

    Chao Jin

    2015-01-01

    Full Text Available Optical diagnostics is an effective method to understand the physical and chemical reaction processes in homogeneous charge compression ignition (HCCI and low temperature combustion (LTC modes. Based on optical diagnostics, the true process on mixing, combustion, and emissions can be seen directly. In this paper, the mixing process by port-injection and direct-injection are reviewed firstly. Then, the combustion chemical reaction mechanism is reviewed based on chemiluminescence, natural-luminosity, and laser diagnostics. After, the evolution of pollutant emissions measured by different laser diagnostic methods is reviewed and the measured species including NO, soot, UHC, and CO. Finally, a summary and the future directions on HCCI and LTC used optical diagnostics are presented.

  13. THE COMBUSTION CHARACTERISTICS OF A MOVABLE LINEAR FIRE SEAT IN MINE FIRES

    Institute of Scientific and Technical Information of China (English)

    王德明; 王省身

    1996-01-01

    Because of the difficulties of describing the process of combustion of underground mine fires, usually the fire seat is considered as a fixed point in the methods of mine fire computer simulation, however this is not in keeping with the feature of the distribution of the combustibles and the process of combustion in mine fires. A conception about movable linear fire seat is put forward first by the authors, together with the calculated models of the thermal decomposition rate, flame spreading velocity and the steady burning length of a linear fire seat etc. The paper also introduces the results of the application of these models.

  14. Research on the Combustion Characteristics of a Free-Piston Gasoline Engine Linear Generator during the Stable Generating Process

    Directory of Open Access Journals (Sweden)

    Yuxi Miao

    2016-08-01

    Full Text Available The free-piston gasoline engine linear generator (FPGLG is a new kind of power plant consisting of free-piston gasoline engines and a linear generator. Due to the elimination of the crankshaft mechanism, the piston motion process and the combustion heat release process affect each other significantly. In this paper, the combustion characteristics during the stable generating process of a FPGLG were presented using a numerical iteration method, which coupled a zero-dimensional piston dynamic model and a three-dimensional scavenging model with the combustion process simulation. The results indicated that, compared to the conventional engine (CE, the heat release process of the FPGLG lasted longer with a lower peak heat release rate. The indicated thermal efficiency of the engine was lower because less heat was released around the piston top dead centre (TDC. Very minimal difference was observed on the ignition delay duration between the FPGLG and the CE, while the post-combustion period of the FPGLG was significantly longer than that of the CE. Meanwhile, the FPGLG was found to operate more moderately due to lower peak in-cylinder gas pressure and a lower pressure rising rate. The potential advantage of the FPGLG in lower NOx emission was also proven with the simulation results presented in this paper.

  15. A Comparison of the Microbial Production and Combustion Characteristics of Three Alcohol Biofuels: Ethanol, 1-Butanol, and 1-Octanol.

    Science.gov (United States)

    Kremer, Florian; Blank, Lars M; Jones, Patrik R; Akhtar, M Kalim

    2015-01-01

    Over the last decade, microbes have been engineered for the manufacture of a variety of biofuels. Saturated linear-chain alcohols have great potential as transport biofuels. Their hydrocarbon backbones, as well as oxygenated content, confer combustive properties that make it suitable for use in internal combustion engines. Herein, we compared the microbial production and combustion characteristics of ethanol, 1-butanol, and 1-octanol. In terms of productivity and efficiency, current microbial platforms favor the production of ethanol. From a combustion standpoint, the most suitable fuel for spark-ignition engines would be ethanol, while for compression-ignition engines it would be 1-octanol. However, any general conclusions drawn at this stage regarding the most superior biofuel would be premature, as there are still many areas that need to be addressed, such as large-scale purification and pipeline compatibility. So far, the difficulties in developing and optimizing microbial platforms for fuel production, particularly for newer fuel candidates, stem from our poor understanding of the myriad biological factors underpinning them. A great deal of attention therefore needs to be given to the fundamental mechanisms that govern biological processes. Additionally, research needs to be undertaken across a wide range of disciplines to overcome issues of sustainability and commercial viability.

  16. Numerical investigation on the flow, combustion, and NOX emission characteristics in a 660 MWe tangential firing ultra-supercritical boiler

    Directory of Open Access Journals (Sweden)

    Wenjing Sun

    2016-02-01

    Full Text Available A three-dimensional numerical simulation was carried out to study the pulverized-coal combustion process in a tangentially fired ultra-supercritical boiler. The realizable k-ε model for gas coupled with discrete phase model for coal particles, P-1 radiation model for radiation, two-competing-rates model for devolatilization, and kinetics/diffusion-limited model for combustion process are considered. The characteristics of the flow field, particle motion, temperature distribution, species components, and NOx emissions were numerically investigated. The good agreement of the measurements and predictions implies that the applied simulation models are appropriate for modeling commercial-scale coal boilers. It is found that an ideal turbulent flow and particle trajectory can be observed in this unconventional pulverized-coal furnace. With the application of over-fire air and additional air, lean-oxygen combustion takes place near the burner sets region and higher temperature at furnace exit is acquired for better heat transfer. Within the limits of secondary air, more steady combustion process is achieved as well as the reduction of NOx. Furthermore, the influences of the secondary air, over-fire air, and additional air on the NOx emissions are obtained. The numerical results reveal that NOx formation attenuates with the decrease in the secondary air ratio (γ2nd and the ratio of the additional air to the over-fire air (γAA/γOFA was within the limits.

  17. Combustion Stability Characteristics of the Project Morpheus Liquid Oxygen / Liquid Methane Main Engine

    Science.gov (United States)

    Melcher, John C.; Morehead, Robert L.

    2014-01-01

    The project Morpheus liquid oxygen (LOX) / liquid methane (LCH4) main engine is a Johnson Space Center (JSC) designed 5,000 lbf-thrust, 4:1 throttling, pressure-fed cryogenic engine using an impinging element injector design. The engine met or exceeded all performance requirements without experiencing any in- ight failures, but the engine exhibited acoustic-coupled combustion instabilities during sea-level ground-based testing. First tangential (1T), rst radial (1R), 1T1R, and higher order modes were triggered by conditions during the Morpheus vehicle derived low chamber pressure startup sequence. The instability was never observed to initiate during mainstage, even at low power levels. Ground-interaction acoustics aggravated the instability in vehicle tests. Analysis of more than 200 hot re tests on the Morpheus vehicle and Stennis Space Center (SSC) test stand showed a relationship between ignition stability and injector/chamber pressure. The instability had the distinct characteristic of initiating at high relative injection pressure drop at low chamber pressure during the start sequence. Data analysis suggests that the two-phase density during engine start results in a high injection velocity, possibly triggering the instabilities predicted by the Hewitt stability curves. Engine ignition instability was successfully mitigated via a higher-chamber pressure start sequence (e.g., 50% power level vs 30%) and operational propellant start temperature limits that maintained \\cold LOX" and \\warm methane" at the engine inlet. The main engine successfully demonstrated 4:1 throttling without chugging during mainstage, but chug instabilities were observed during some engine shutdown sequences at low injector pressure drop, especially during vehicle landing.

  18. Variation of diesel soot characteristics by different types and blends of biodiesel in a laboratory combustion chamber

    Energy Technology Data Exchange (ETDEWEB)

    Omidvarborna, Hamid; Kumar, Ashok [Department of Civil Engineering, The University of Toledo, Toledo, OH (United States); Kim, Dong-Shik, E-mail: dong.kim@utoledo.edu [Department of Chemical and Environmental Engineering, The University of Toledo, Toledo, OH (United States)

    2016-02-15

    Very little information is available on the physical and chemical properties of soot particles produced in the combustion of different types and blends of biodiesel fuels. A variety of feedstock can be used to produce biodiesel, and it is necessary to better understand the effects of feedstock-specific characteristics on soot particle emissions. Characteristics of soot particles, collected from a laboratory combustion chamber, are investigated from the blends of ultra-low sulfur diesel (ULSD) and biodiesel with various proportions. Biodiesel samples were derived from three different feedstocks, soybean methyl ester (SME), tallow oil (TO), and waste cooking oil (WCO). Experimental results showed a significant reduction in soot particle emissions when using biodiesel compared with ULSD. For the pure biodiesel, no soot particles were observed from the combustion regardless of their feedstock origins. The overall morphology of soot particles showed that the average diameter of ULSD soot particles is greater than the average soot particles from the biodiesel blends. Transmission electron microscopy (TEM) images of oxidized soot particles are presented to investigate how the addition of biodiesel fuels may affect structures of soot particles. In addition, inductively coupled plasma mass spectrometry (ICP-MS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were conducted for characterization of soot particles. Unsaturated methyl esters and high oxygen content of biodiesel are thought to be the major factors that help reduce the formation of soot particles in a laboratory combustion chamber. - Highlights: • The unsaturation of biodiesel fuel was correlated with soot characteristics. • Average diameters of biodiesel soot were smaller than that of ULSD. • Eight elements were detected as the marker metals in biodiesel soot particles. • As the degree of unsaturation increased, the oxygen content in FAMEs increased. • Biodiesel

  19. Characteristics of particulate carbon emissions from real-world Chinese coal combustion.

    Science.gov (United States)

    Zhang, Yuanxun; Schauer, James Jay; Zhang, Yuanhang; Zeng, Limin; Wei, Yongjie; Liu, Yuan; Shao, Min

    2008-07-15

    Particulate matter emissions from a series of different Chinese coal combustion systems were collected and analyzed for elemental and organic carbon (EC, OC), and molecular markers. Emissions from both industrial boilers and residential stoves were investigated. The coal used in this study included anthracite, bituminite, and brown coal, as well as commonly used coal briquettes produced in China for residential coal combustion. Results show significant differences in the contribution of carbonaceous species to particulate mass emissions. Industrial boilers had much higher burn out of carbon yielding particulate matter emissions with much lower levels of OC, EC, and speciated organic compounds, while residential stoves had significantly higher emissions of carbonaceous particulate matter with emission rates of approximately 100 times higher than that of industrial boilers. Quantified organic compounds emitted from industrial boilers were dominated by oxygenated compounds, of which 46-68% were organic acids, whereas the dominate species quantified in the emissions from residential stoves were PAHs (38%) and n-alkanes (20%). An important observation was the fact that emission factors of PAHs and the distribution of hopanoids were different among the emissions from industrial and residential coal combustion even using the same coal for combustion. Although particulate matter emissions from industrial and residential combustion were different in many regards, picene was detected in all samples with detectable OC mass concentrations, which supports the use of this organic tracer for OC from all types of coal combustion. 17alpha(H),21beta(H)-29-norhopane was the predominant hopanoid in coal combustion emissions, which is different from mobile source emissions and may be used to distinguish emissions from these different fossil fuel sources.

  20. Experimental study of combustion characteristics of nanoscale metal and metal oxide additives in biofuel (ethanol

    Directory of Open Access Journals (Sweden)

    Peterson GP

    2011-01-01

    Full Text Available Abstract An experimental investigation of the combustion behavior of nano-aluminum (n-Al and nano-aluminum oxide (n-Al2O3 particles stably suspended in biofuel (ethanol as a secondary energy carrier was conducted. The heat of combustion (HoC was studied using a modified static bomb calorimeter system. Combustion element composition and surface morphology were evaluated using a SEM/EDS system. N-Al and n-Al2O3 particles of 50- and 36-nm diameters, respectively, were utilized in this investigation. Combustion experiments were performed with volume fractions of 1, 3, 5, 7, and 10% for n-Al, and 0.5, 1, 3, and 5% for n-Al2O3. The results indicate that the amount of heat released from ethanol combustion increases almost linearly with n-Al concentration. N-Al volume fractions of 1 and 3% did not show enhancement in the average volumetric HoC, but higher volume fractions of 5, 7, and 10% increased the volumetric HoC by 5.82, 8.65, and 15.31%, respectively. N-Al2O3 and heavily passivated n-Al additives did not participate in combustion reactively, and there was no contribution from Al2O3 to the HoC in the tests. A combustion model that utilized Chemical Equilibrium with Applications was conducted as well and was shown to be in good agreement with the experimental results.

  1. Emission characteristics of co-combustion of sewage sludge with olive cake and lignite coal in a circulating fluidized bed.

    Science.gov (United States)

    Toraman, Oner Yusuf; Topal, Hüseyin; Bayat, Oktay; Atimtay, Aysel T

    2004-01-01

    In this study, a circulating fluidized bed (CFB) of 125 mm diameter and 1800mm height was used to find the combustion characteristics of sewage sludge (SS) produced in Turkey. Sludge + olive cake, and sludge + lignite coal mixtures were burned separately. Various sludge-to-lignite coal and sludge-to-olive cake ratios (5/95, 10/90, 15/85, 20/80) were tried. On-line concentrations of major components (O2, SO2, CO2, CO, NOx, CmHn) were measured in the flue gas, as well as temperature and pressure distributions along the bed. Combustion efficiencies of sludge + olive cake and sludge + lignite coal mixtures were calculated, and the optimum conditions for operating parameters were discussed. The results have shown that the combustion mainly takes place in the upper regions of the main column where the temperature reaches 900 degrees C. SS + Coal burn in the CFB with an efficiency of 95.14% to 96.18%, which is considered to be quite good. When burning sludge mixed with olive cake, appreciable amounts of CO and unburned hydrocarbons are formed and the combustion efficiency drops to 92.93%. CO and CmHn emissions are lower when lignite coal is mixed with various amounts of SS than the emissions when the coal is burned alone. As the %SS is increased in the fuel mixture, the SO2 emission decreases. NOx emissions are slightly higher. When burning sludge mixed with olive cake, SO2 and NOx emissions are slightly higher. CO and CmHn emissions decrease sharply when SS is mixed with 5%wt. olive cake. With increasing sludge ratio these emissions increase due to the unburned hydrocarbons. As a result of this study, it is believed that SS can be burned effectively in a CFBC together with other fuels, especially with olive cake (OC). OC will be a good additive fuel for the combustion of lower quality fuels.

  2. PERFORMANCE, COMBUSTION AND EMISSION CHARACTERISTICS OF PZT LOADED CYANATE MODIFIED EPOXY COATED COMBUSTION CHAMBER IN DIESEL ENGINE

    Directory of Open Access Journals (Sweden)

    Vijaya Kumar K.R

    2010-07-01

    Full Text Available Energy conservation and emissions have become increasing concern over the past few decades. PZT loaded cyanate modified epoxy (60EPCY 20PI coated material were initially investigated for adiabatic diesel engines based on first law of thermodynamics prediction of significant fuel economy improvements, reduction in heat rejection and potential increased power density of the diesel engines. The purpose of 60EPCY 20PI is to focus on developing binder systems with low thermal conductivity and improve the coating durability under high load condition. The coating material is made up of 20% Lead Zirconate Titanate (PZT in 60% Cyanate modified Epoxy system. The triazine ring of cyanate ester offers better thermal resistance characteristics to the epoxy system. Experimental investigation is carried out under different load condition on a single cylinder dieselengine with PZT loaded cyanate modified epoxy resin system of 0.5 mm thickness to the piston, cylinder head with valves and cylinder liner. The result showed 15.89 %of reduced specific fuel consumption. Emissions of unburnt hydrocarbon, carbon monoxide are reduced.

  3. Experimental investigations on combustion, performance and emissions characteristics of compression ignition engine powered by B100/ethanol blend

    Directory of Open Access Journals (Sweden)

    Tutak Wojciech

    2017-01-01

    Full Text Available In the study are presented the results of co-combustion of biodiesel B100 with ethanol fuel as blend. The 1-cylinder direct injection compression ignition engine was used during the study. Tests were conducted at a constant angle of fuel injection and constant rotational speed equal to 1500 rpm. Results of thermal cycle parameters and emission characteristics are presented. On the basis of results stated that ethanol fuel fraction in blend causes the increase in peak heat release rate. With the increase in ethanol fuel fraction the ignition delay increased but combustion duration decreased. With the increase in ethanol fuel fraction in blend thermal efficiency increased as well. It also noticed almost constant emission of THC, the increase in NOx emissions and decrease emissions in CO and CO2.

  4. 沥青燃烧特性的实验研究%Experimental research on combustion characteristics of bitumen

    Institute of Scientific and Technical Information of China (English)

    黄亚东; 冯丹丹; 吴珂; 敖文; 黄志义

    2011-01-01

    采用热重分析法对SBS改性沥青和阻燃沥青及其胶浆的燃烧特性进行研究,实验条件为空气环境、升温速率为20℃/min.结果表明:两种沥青胶浆的燃烧特性曲线形状十分相近,大致分为5个阶段.两种沥青燃烧过程较一致,主要分为4个阶段.沥青二次挥发分燃烧与残炭燃烧同时进行.目前的阻燃技术对沥青自燃点的影响不大,其主要作用是减缓沥青的燃烧速度.阻燃沥青的平均燃烧速率约为SBS改性沥青的60%.两种沥青胶浆的灰分含量相差不大,其平均燃烧速率也相差不大.%The combustion characteristics of SBS modification bitumen and fire retardant bitumen and their mortar were studied by thermo-gravimetric analysis with air as the ambient gas and 20 ℃/min heating rate. The experimental results showed that the combustion characteristics curves of the mortar of these two kinds of bitumen are very similar, and all have 5 sections. The combustion processes of two kinds of bitumen are similar and have 4 sections. The secund volatile component and carbon residue of bitumen burned at the same time. The flame- resistant technology has little effect on the bitumen' s self - ignition point at present, and its primary action is to slow down the reaction rate of bitumen combustion. The average combustion rate of flame-retardant bitumen is 60% of that of SBS modification bitumen The mortar of two kinds of bitumen has the similar ash content, so has the similar average combustion rate.

  5. Fundamental electrochemiluminescence characteristics of fluorine-doped tin oxides synthesized by sol-gel combustion.

    Science.gov (United States)

    Moon, B H; Chaoumead, A; Sung, Y M

    2013-10-01

    Fluorine-doped tin oxide (FTO) materials synthesized by sol-gel combustion method were investigated for electrochemical luminescence (ECL) application. Effects of sol-gel combustion conditions on the structures and morphology of the porous FTO (p-FTO) materials were studied. ECL efficiency of p-FTO-based cell was about 251 cd/m2 at 4 V bias, which is higher than the sell using only FTO electrodes (102.8 cd/m2). The highest intensity of the emitting light was obtained at the wavelength of about 610 nm. The porous FTO layer was effective for increasing ECL intensities.

  6. Reactor choices for chemical looping combustion (CLC) dependencies on materials characteristics

    NARCIS (Netherlands)

    Kimball, E.; Lambert, A.; Fossdal, A.; Leenman, R.N.; Comte, E.; Bos, W.A.P. van den; Blom, R.

    2013-01-01

    The physio-chemical stability of the oxygen carrier material during chemical looping combustion (CLC) operation is crucial. In the present paper we discuss the challenges connected to operating a metal oxide base material in a cyclic manner between oxidizing and reducing atmospheres. Especially,

  7. Efficiency characteristics of a new quasi-constant volume combustion spark ignition engine

    Directory of Open Access Journals (Sweden)

    Dorić Jovan Ž.

    2013-01-01

    Full Text Available A zero dimensional model has been used to investigate the combustion performance of a four cylinder petrol engine with unconventional piston motion. The main feature of this new spark ignition (SI engine concept is the realization of quasi-constant volume (QCV during combustion process. Presented mechanism is designed to obtain a specific motion law which provides better fuel consumption of internal combustion (IC engines. These advantages over standard engine are achieved through synthesis of unconventional piston mechanism. The numerical calculation was performed for several cases of different piston mechanism parameters, compression ratio and engine speed. Calculated efficiency and power diagrams are plotted and compared with performance of ordinary SI engine. The results show that combustion during quasi-constant volume has significant impact on improvement of efficiency. The main aim of this paper is to find a proper kinematics parameter of unconventional piston mechanism for most efficient heat addition in SI engines.[Acknowledgment. This research was done as a part of project TR31046 "Improvement of the quality of tractors and mobile systems with the aim of increasing competitiveness and preserving soil and environment", supported by Serbian Ministry of Science and Technological Development.

  8. Emission characteristics of kerosene-air spray combustion with plasma assistance

    Directory of Open Access Journals (Sweden)

    Xingjian Liu

    2015-09-01

    Full Text Available A plasma assisted combustion system for combustion of kerosene-air mixtures was developed to study emission levels of O2, CO2, CO, and NOx. The emission measurement was conducted by Testo 350-Pro Flue Gas Analyzer. The effect of duty ratio, feedstock gas flow rate and applied voltage on emission performance has been analyzed. The results show that O2 and CO emissions reduce with an increase of applied voltage, while CO2 and NOx emissions increase. Besides, when duty ratio or feedstock gas flow rate decreases, the same emission results would appear. The emission spectrum of the air plasma of plasma assisted combustion actuator was also registered to analyze the kinetic enhancement effect of plasma, and the generation of ozone was believed to be the main factor that plasma makes a difference in our experiment. These results are valuable for the future optimization of kerosene-fueled aircraft engine when using plasma assisted combustion devices to exert emission control.

  9. Combustion characteristics of spent catalyst and paper sludge in an internally circulating fluidized-bed combustor.

    Science.gov (United States)

    Roh, Seon Ah; Jung, Dae Sung; Kim, Sang Done; Guy, Christophe

    2005-09-01

    Combustion of spent vacuum residue hydrodesulfurization catalyst and incineration of paper sludge were carried out in thermo-gravimetric analyzer and an internally circulating fluidized-bed (ICFB) reactor. From the thermo-gravimetric analyzer-differential thermo-gravimetric curves, the pre-exponential factors and activation energies are determined at the divided temperature regions, and the thermo-gravimetric analysis patterns can be predicted by the kinetic equations. The effects of bed temperature, gas velocity in the draft tube and annulus, solid circulation rate, and waste feed rate on combustion efficiency of the wastes have been determined in an ICFB from the experiments and the model studies. The ICFB combustor exhibits uniform temperature distribution along the bed height with high combustion efficiency (>90%). The combustion efficiency increases with increasing reaction temperature, gas velocity in the annulus region, and solid circulation rate and decreases with increasing waste feed rate and gas velocity in the draft tube. The simulated data from the kinetic equation and the hydrodynamic models predict the experimental data reasonably well.

  10. New black liquor combustion characteristics III; Mustalipeaen uudet poltto-ominaisuudet III

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Forssen, M.; Backman, R.; Enestam, S.; Lauren, T.; Skrifvars, B.J. [Aabo Akademi, Turku (Finland). Combustion Chemistry Research Group

    1997-10-01

    The main purposes in this work is to: 1. Compare black liquor combustion characterization results to recovery boiler experiences. 2. Study the mechanisms of sodium release in black liquor combustion In the first part results from black liquor combustion characterization tests developed by Aabo Akademi University will be compared to experiences at four Finnish kraft recovery boilers. When comparing the laboratory data to the compiled field data emphasis will be put on the behavior of the black liquor during burning, the release of sodium and potassium, the melting behavior of the deposits and the NO and SO{sub 2} emissions. The main purpose in the second part of the work is to study the release mechanisms of sodium from black liquor char during combustion. Sodium is mainly released from the char by the mechanism where the molten sodiumcarbonate reacts with the char carbon. The study is divided into four subtasks and is performed mainly by conducting experiments in laboratory scale devices: (1) Sodium release during char reactions is studied for different liquors by analyzing the amount of sodium remaining in char after different holding times in a hot inert atmosphere. (2) A DTA/TGA apparatus is used to study in isothermal conditions the char reactions on prepyrolyzed char. (3) The effect of the form of sodium on the sodium release during char reactions. Black liquors added with different sodium salts (Na{sub 2}CO{sub 3}, Na{sub 2}SO{sub 4}, Na{sub 2}S{sub 2}O{sub 2}, Na{sub 2}S sekae NaCl) are used in experiments as in subtask 1. (4) Sodium release during combustion (2-5 % O{sub 2}) of single black liquor particles

  11. Large eddy simulation of combustion characteristics in a kerosene fueled rocket-based combined-cycle engine combustor

    Science.gov (United States)

    Huang, Zhi-wei; He, Guo-qiang; Qin, Fei; Cao, Dong-gang; Wei, Xiang-geng; Shi, Lei

    2016-10-01

    This study reports combustion characteristics of a rocket-based combined-cycle engine combustor operating at ramjet mode numerically. Compressible large eddy simulation with liquid kerosene sprayed and vaporized is used to study the intrinsic unsteadiness of combustion in such a propulsion system. Results for the pressure oscillation amplitude and frequency in the combustor as well as the wall pressure distribution along the flow-path, are validated using experimental data, and they show acceptable agreement. Coupled with reduced chemical kinetics of kerosene, results are compared with the simultaneously obtained Reynolds-Averaged Navier-Stokes results, and show significant differences. A flow field analysis is also carried out for further study of the turbulent flame structures. Mixture fraction is used to determine the most probable flame location in the combustor at stoichiometric condition. Spatial distributions of the Takeno flame index, scalar dissipation rate, and heat release rate reveal that different combustion modes, such as premixed and non-premixed modes, coexisted at different sections of the combustor. The RBCC combustor is divided into different regions characterized by their non-uniform features. Flame stabilization mechanism, i.e., flame propagation or fuel auto-ignition, and their relative importance, is also determined at different regions in the combustor.

  12. Combustion characteristics of diesel engine using producer gas and blends of Jatropha methyl ester with diesel in mixed fuel mode

    Directory of Open Access Journals (Sweden)

    Hifjur Raheman

    2014-12-01

    Full Text Available An experimental investigation was performed to study the combustion characteristics of diesel engine fuelled with producer gas-biodiesel in dual fuel mode. Three different fuel blends of Jatropha methyl ester with high speed diesel (HSD (B10, B20 and B100 were used with producer gas obtained from the gasification of briquettes made from de-oiled Jatropha seed cake. The increments in load on the engine increased the brake thermal efficiency, exhaust gas temperature and lowered the brake specific energy consumption. The ignition delays in dual-fuel mode of operation for both the fuels were longer than for single-fuel mode of operation. Combustion pressure and heat release rate (HRR patterns at different engine loads were found to be similar for biodiesel and HSD. In dual-fuel mode, the peak pressure and HRR for producer gas–biodiesel dual-fuel were slightly lower than those of producer gas–diesel combustion at full load condition. Significantly lower NOx emissions were obtained under the dual fuel mode of operation for both pilot fuels compared to the single-fuel mode especially HSD under all test conditions.

  13. LPG gaseous phase electronic port injection on performance, emission and combustion characteristics of Lean Burn SI Engine

    Science.gov (United States)

    Bhasker J, Pradeep; E, Porpatham

    2016-08-01

    Gaseous fuels have always been established as an assuring way to lessen emissions in Spark Ignition engines. In particular, LPG resolved to be an affirmative fuel for SI engines because of their efficient combustion properties, lower emissions and higher knock resistance. This paper investigates performance, emission and combustion characteristics of a microcontroller based electronic LPG gaseous phase port injection system. Experiments were carried out in a single cylinder diesel engine altered to behave as SI engine with LPG as fuel at a compression ratio of 10.5:1. The engine was regulated at 1500 rpm at a throttle position of 20% at diverse equivalence ratios. The test results were compared with that of the carburetion system. The results showed that there was an increase in brake power output and brake thermal efficiency with LPG gas phase injection. There was an appreciable extension in the lean limit of operation and maximum brake power output under lean conditions. LPG injection technique significantly reduces hydrocarbon and carbon monoxide emissions. Also, it extremely enhances the rate of combustion and helps in extending the lean limit of LPG. There was a minimal increase of NOx emissions over the lean operating range due to higher temperature. On the whole it is concluded that port injection of LPG is best suitable in terms of performance and emission for LPG fuelled lean burn SI engine.

  14. Investigating dominant characteristics of fires across the Amazon during 2005-2014 through satellite data synthesis of combustion signatures

    Science.gov (United States)

    Tang, W.; Arellano, A. F.

    2017-01-01

    Estimates of fire emissions remain uncertain due to limited constraints on the variations in fire characteristics. Here we demonstrate the utility of space-based observations of smoke constituents in addressing this limitation. We introduce a satellite-derived smoke index (SI) as an indicator of the dominant phase of large-scale fires. This index is calculated as the ratio of the geometric mean of observed fractional enhancements (due to fire) in carbon monoxide and aerosol optical depth to that of nitrogen dioxide. We assess the usefulness of this index on fires in the Amazon. We analyze the seasonal, regional, and interannual joint distribution of SI and fire radiative power (FRP) in relation to fire hotspots, land cover, Drought Severity Index, and deforestation rate estimates. We also compare this index with an analogous quantity derived from field data or emission inventories. Our results show that SI changes from low (more flaming) to high (more smoldering) during the course of a fire season, which is consistent with the changes in observed maximum FRPs from high to low. We also find that flaming combustion is more dominant in areas where deforestation fires dominate, while smoldering combustion has a larger influence during drought years when understory fires are more likely enhanced. Lastly, we find that the spatiotemporal variation in SI is inconsistent with current emission inventories. Although we recognize some limitations of this approach, our results point to the utility of SI as a proxy for overall combustion efficiency in the parameterization of fire emission models.

  15. Effects of direct-current electric fields on flame shape and combustion characteristics of ethanol in small scale

    Directory of Open Access Journals (Sweden)

    Yunhua Gan

    2016-01-01

    Full Text Available The aim of this work is to investigate the effects of direct-current electric fields on the behavior of the small-scale diffusion ethanol flame. The flow rate of liquid ethanol, the flame temperatures, and the flame shapes were measured. The results showed that the stable working ranges of a small-scale combustor became narrower under the direct-current electric field. The main reason was that the evaporation velocity of liquid ethanol limited by great heat loss effect cannot keep up with the increasing of combustion velocity by the ionic wind effect. The movements of those charged particles in flame enhanced the combustion process, resulting in higher flame temperatures under positive or negative direct-current electric field. The flame heights decreased with increasing applied voltages, due to the ionic wind effect increasing the flame temperature and the diffusivity. The flame voltage–current characteristic was also examined. Three regions can be divided: the subsaturation region, the saturation region, and the supersaturation region. Finally, the ratios of electric active power to actual burning thermal power of ethanol flame were calculated. It can be inferred that using the external direct-current electric field with little power consumption to control combustion and flame is a feasible method.

  16. 汽油HCCI发动机HCCI/SI模式过渡控制的研究%Research on HCCI/SI Mode Transition Control of Gasoline HCCI Engine

    Institute of Scientific and Technical Information of China (English)

    周能辉; 谢辉; 张岩; 陈韬; 赵华

    2007-01-01

    由于HCCI燃烧不能覆盖发动机全部工况,因此一台实用的发动机必须具有HCCI/SI模式过渡的功能.针对目前开发的进排气门升程和相位均独立连续调整的汽油HCCI发动机模式过渡的需要,开发了基于CAN总线分布式的HCCI汽油机控制系统,在此基础上对HCCI/SI模式过渡控制进行详细地研究,本文详细地介绍了其结构及其控制策略.由于该控制系统采用自适应PID策略控制进排气门升程和相位,神经网络预测模式过渡中的发动机进气量.实验结果表明:该控制系统解决了HCCI模式过渡中的进排气门升程、相位和空燃比的控制问题,通过细化气门参数能较好地管理混合放热率型线,满足HCCI/SI模式动态平滑过渡的控制需求.

  17. Thermal Degradation Characteristics and Kinetics of Oxy Combustion of Corn Residues

    Directory of Open Access Journals (Sweden)

    Poramate Sittisun

    2015-01-01

    Full Text Available Thermogravimetric analysis was used to investigate oxy combustion of corncob and stover. The biomass samples were heated from ambient temperature to 900°C at different heating rates of 10, 30, and 50 K/min. Both biomass samples showed similar weight loss patterns with three zones, corresponding to dehydration, devolatilization, and char combustion, but displayed different degradation temperatures. Increasing heating rate was found to shift the degradation patterns to higher temperatures. Decomposition rates of cob and stover may have been influenced by their lignocellulosic composition. The kinetic parameters of the thermal degradation process were also determined and compared using the Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods. Both methods were found to give similar values and patterns of activation energy against conversion fraction. The average values were found to be in similar magnitude to those reported in the literature, around 170 and 148 kJ/mol for cob and stover, respectively.

  18. The characteristics of the combustion process occurring under real operating conditions of traction

    Science.gov (United States)

    Longwic, R.; Sander, P.

    2016-09-01

    The authors deal with the issues of the Diesel engine under dynamic conditions. The conditions of the dynamic operation of the engine have most frequently been mapped by the method of free acceleration of the engine caused by the change of the position of the fuel dose lever. The article presents the results of indication of the traction Diesel engine under real operating conditions. This allows for the use of a mobile system to indicate the AVL engine built in the vehicle in research. We analysed a number of thermodynamic parameters of the combustion process in various dynamic states, typical for the process of actual operation of the engine, such as working in start-up conditions and immediately after, working in conditions of acceleration and coasting. Formulated conclusions significantly expand the area of knowledge concerning the functioning of the internal combustion engine in dynamic conditions.

  19. Combustion Characteristics of Lignite Char in a Laboratory-scale Pressurized Fluidized Bed Combustor

    Science.gov (United States)

    Murakami, Takahiro; Suzuki, Yoshizo

    In a dual fluidized bed gasifier, the residual char after steam gasification is burnt in riser. The objectives of this work are to clarify the effect of parameters (temperature, pressure, and particle size of lignite char) of char combustion using a laboratory-scale pressurized fluidized bed combustor (PFBC). As a result, the burnout time of lignite char can be improved with increasing operating pressure, and temperature. In addition, the decrease in the particle size of char enhanced the effect on burnout time. The initial combustion rate of the char can be increased with increasing operating pressure. The effect was decreased with increasing operating temperature. However, the effect of operating pressure was slightly changed in small particle size, such as 0.5-1.0 mm. It takes about 20 sec to burn 50% of char in the operating pressure of 0.5 MPa and the particle size of 0.5-1.0 mm.

  20. Modeling and Countermeasures of Combustion Characteristics of Char Particles in CFBC

    Institute of Scientific and Technical Information of China (English)

    YanJin; QiayuZheng; 等

    1999-01-01

    A mathematical model of single char particle combustion in circulating fluidized bed combustor(CFBC) is developed in this paper in this paper,its numerical solution in operating conditions of CFBC verifies the nature of a phenomenon that the distribution of carbon content of char particles has a peak value versus their diameters.The results show that the temperature of smaller char particle is close to the bed temperature,and there also exits a peak value for the burn-out time of char particles versus their diameters.The countermeasures are presented to improve combustion of fine particles,such as use of the fly-ash recirculation,the hot cyclone,and so on.

  1. Relationship of fuel size and spacing to combustion characteristics of laboratory fuel cribs

    Science.gov (United States)

    Hal E. Anderson

    1990-01-01

    Flaming combustion in cribs of large woody fuels, thickness 5 cm or greater, is not sustained when fuel spacing ratio, fuel edge-to-edge separation distance to fuel thickness, is greater than 3:1. The flame length associated with the large-fuel burning rate was found to drop rapidly when the large-fuel spacing ratio increases beyond 2.23:1. This supports the critical...

  2. Combustion characteristics of water-insoluble elemental and organic carbon in size selected ambient aerosol particles

    Directory of Open Access Journals (Sweden)

    K. Wittmaack

    2005-01-01

    Full Text Available Combustion of elemental carbon (EC and organic carbon (OC contained in ambient aerosol matter was explored using scanning electron microscopy (SEM in combination with energy dispersive X-ray analysis (EDX. To ease identification of the particles of interest and to avoid or at least reduce interaction with simultaneously sampled inorganic oxides and salts, the approach used in this work differed in two ways from commonly applied procedures. First, rather than using a mixture of particles of vastly different sizes, as in PM10 or PM2.5, aerosol matter was collected in a 5-stage impactor. Second, the water soluble fraction of the collected matter was removed prior to analysis. Diesel soot particles, which appeared in the well-known form of chain-type aggregates, constituted the major fraction of EC. In contrast, OC containing particles were observed in a variety of shapes, including a sizable amount of bioaerosol matter appearing mostly in the size range above about 1 µm. During heating in ambient air for 1h, diesel soot particles were found to be stable up to 470°C, but complete combustion occurred in a narrow temperature interval between about 480 and 510°C. After diesel soot combustion, minute quantities of 'ash' were observed in the form of aggregated tiny particles with sizes less than 10 nm. These particles could be due to elemental or oxidic contaminants of diesel soot. Combustion of OC was observed over a wide range of temperatures, from well below 200°C to at least 500°C. Incompletely burnt bioaerosol matter was still found after heating to 600°C. The results imply that the EC fraction in aerosol matter can be overestimated significantly if the contribution of OC to a thermogram is not well separated.

  3. Combustion characteristics of water-insoluble elemental and organic carbon in size selected ambient aerosol particles

    Directory of Open Access Journals (Sweden)

    K. Wittmaack

    2005-04-01

    Full Text Available Combustion of elemental carbon (EC and organic carbon (OC contained in ambient aerosol matter was explored using scanning electron microscopy (SEM in combination with energy dispersive X-ray analysis (EDX. To ease identification of the particles of interest and to avoid or at least reduce interaction with simultaneously sampled inorganic oxides and salts, the approach used in this work differed in two ways from commonly applied procedures. First, rather than using a mixture of particles of vastly different sizes, as in PM10 or PM2.5, aerosol matter was collected in a 5-stage impactor. Second, the water soluble fraction of the collected matter was removed prior to analysis. Diesel soot particles, which appeared in the well-known form of chain-type aggregates, constituted the major fraction of EC. In contrast, OC containing particles were observed in a variety of shapes, including a sizable amount of bioaerosol matter appearing mostly in the size range above about 1 µm. During heating in ambient air for 1 h, diesel soot particles were found to be stable up to 480°C, but complete combustion occurred in a narrow temperature interval between about 490 and 510°C. After diesel soot combustion, minute quantities of ''ash'' were observed in the form of aggregated tiny particles with sizes less than 10 nm. These particles could be due to elemental or oxidic contaminants of diesel soot. Combustion of OC was observed over a wide range of temperatures, from well below 200°C to at least 500°C. Incompletely burnt bioaerosol matter was still found after heating to 600°C. The results imply that the EC fraction in aerosol matter can be overestimated significantly if the contribution of OC to a thermogram is not well separated.

  4. 3-DIMENSIONAL Numerical Modeling on the Combustion and Emission Characteristics of Biodiesel in Diesel Engines

    Science.gov (United States)

    Yang, Wenming; An, Hui; Amin, Maghbouli; Li, Jing

    2014-11-01

    A 3-dimensional computational fluid dynamics modeling is conducted on a direct injection diesel engine fueled by biodiesel using multi-dimensional software KIVA4 coupled with CHEMKIN. To accurately predict the oxidation of saturated and unsaturated agents of the biodiesel fuel, a multicomponent advanced combustion model consisting of 69 species and 204 reactions combined with detailed oxidation pathways of methyl decenoate (C11H22O2), methyl-9-decenoate (C11H20O2) and n-heptane (C7H16) is employed in this work. In order to better represent the real fuel properties, the detailed chemical and thermo-physical properties of biodiesel such as vapor pressure, latent heat of vaporization, liquid viscosity and surface tension were calculated and compiled into the KIVA4 fuel library. The nitrogen monoxide (NO) and carbon monoxide (CO) formation mechanisms were also embedded. After validating the numerical simulation model by comparing the in-cylinder pressure and heat release rate curves with experimental results, further studies have been carried out to investigate the effect of combustion chamber design on flow field, subsequently on the combustion process and performance of diesel engine fueled by biodiesel. Research has also been done to investigate the impact of fuel injector location on the performance and emissions formation of diesel engine.

  5. Combustion Characteristics for Turbulent Prevaporized Premixed Flame Using Commercial Light Diesel and Kerosene Fuels

    Directory of Open Access Journals (Sweden)

    Mohamed S. Shehata

    2014-01-01

    Full Text Available Experimental study has been carried out for investigating fuel type, fuel blends, equivalence ratio, Reynolds number, inlet mixture temperature, and holes diameter of perforated plate affecting combustion process for turbulent prevaporized premixed air flames for different operating conditions. CO2, CO, H2, N2, C3H8, C2H6, C2H4, flame temperature, and gas flow velocity are measured along flame axis for different operating conditions. Gas chromatographic (GC and CO/CO2 infrared gas analyzer are used for measuring different species. Temperature is measured using thermocouple technique. Gas flow velocity is measured using pitot tube technique. The effect of kerosene percentage on concentration, flame temperature, and gas flow velocity is not linearly dependent. Correlations for adiabatic flame temperature for diesel and kerosene-air flames are obtained as function of mixture strength, fuel type, and inlet mixture temperature. Effect of equivalence ratio on combustion process for light diesel-air flame is greater than for kerosene-air flame. Flame temperature increases with increased Reynolds number for different operating conditions. Effect of Reynolds number on combustion process for light diesel flame is greater than for kerosene flame and also for rich flame is greater than for lean flame. The present work contributes to design and development of lean prevaporized premixed (LPP gas turbine combustors.

  6. Influence of engine speed and the course of the fuel injection characteristics on forming the average combustion temperature in the cylinder of turbo diesel engine

    Directory of Open Access Journals (Sweden)

    Piotr GUSTOF

    2007-01-01

    Full Text Available Average combustion temperatures inside a turbo diesel engine for the same load and the same total doze of fuel for two rotational speeds: 2004 [rpm] and 4250 [rpm] are presented in this paper. The aim of this work is also the evaluation of the influence of the temporary course of the fuel injection characteristics on forming temperature in theengine cylinder space for these temperatures. The calculations were carried out by means of two zone combustion model.

  7. Effect of kaolin addition on ash characteristics of palm empty fruit bunch (EFB) upon combustion

    Energy Technology Data Exchange (ETDEWEB)

    Konsomboon, Supatchaya; Pipatmanomai, Suneerat [The Joint Graduate School of Energy and Environment, King Mongkut' s University of Technology Thonburi, 126 Prachauthit Road, Bangmod, Tungkru, Bangkok 10140 (Thailand); Madhiyanon, Thanid [Department of Mechanical Engineering, Faculty of Engineering, Mahanakorn University of Technology, 51 Cheum-Sampan Road, Nong-Chok, Bangkok 10530 (Thailand); Tia, Suvit [Department of Chemical Engineering, Faculty of Engineering, King Mongkut' s University of Technology Thonburi, 126 Prachauthit Road, Bangmod, Tungkru, Bangkok 10140 (Thailand)

    2011-01-15

    Palm empty fruit bunch (EFB), a by-product of the palm oil industry, is being recognized as one of the most potential kinds of biomass for energy production in Thailand. However, it has been reported that, in combusting EFB in boilers, some compounds evolving from abundant alkali metals in EFB into gas-phase condense and deposit on low-temperature surfaces of heat exchange equipment, causing fouling and corrosion problems. To come up with a solution to impede the deposition, kaolin, which is abundant in kaolinite (Al{sub 2}Si{sub 2}O{sub 5}(OH){sub 4}), is employed to capture the alkali metal vapours eluding from the combustion region. The experiments were designed to simulate the combustion situations that may take place when kaolin is utilized in two different approaches: premixing of kaolin with EFB prior to combustion and gas-phase reaction of volatiles from EFB with kaolin. The amounts of kaolin used were 8% and 16% by weight based on dry weight of EFB, which were equivalent to one and two times of the theoretical kaolin requirement to capture all potassium originally present in the EFB. The furnace temperatures used for EFB combustion were 700-900 C and ashes were analyzed by XRF and XRD. The results revealed that, under the kaolin premixing condition, 8% kaolin addition was sufficient to capture the potassium compounds at low temperature, i.e. 700 and 800 C. However, when the temperature was increased to 900 C, 16% kaolin addition was needed to completely capture the potassium compounds. The results from gas-phase experiments showed that kaolin can capture volatile potassium at maximum 25% at 900 C. The XRD results showed, for both experimental cases, the evidence of formation of the high melting temperature potassium-alumino-silicates, which confirmed the reaction of potassium compounds with kaolin. The study also suggests that the premixing method is better than the other because of its higher overall capture efficiency. (author)

  8. Characteristics of combustion and emissions of the diesel/methanol premixed compound combustion%柴油掺烧甲醇预混合燃烧和排放特性

    Institute of Scientific and Technical Information of China (English)

    邹轲; 项旭昇; 李海言; 刘丙善

    2015-01-01

    在一台六缸柴油机上搭建了进气喷射甲醇掺烧系统,对不同替代率下的柴油掺烧甲醇工况燃烧和排放特性进行了试验研究。试验结果表明:掺烧甲醇改变了发动机的燃烧特性。随甲醇替代率的上升,预混合燃烧比例逐渐增大,扩散燃烧比例则减小。掺烧甲醇后,缩短了整体工况的燃烧持续期,使放热更加集中,改善了燃烧等容度。掺烧甲醇还会从散热系统回收一部分热量,共同作用下使热效率得到大幅提高。但大比例掺烧甲醇也会对NOx及CO排放带来恶化,并生成甲醇与甲醛等非常规排放物。同时掺烧甲醇还会延长滞燃期,因此需要调整柴油的主喷正时以保证发动机运转稳定。%An inlet injection system of methanol was built in a six cylinder diesel engine to investigate the combustion and emission characteristics at different substitution rates under the condition of diesel/methanol compound. The test results show that the combustion characteristics of the engine has changed with the methanol compound combustion. With the methanol replacement rate increases, the premixed combustion ratio increases and the diffusion combustion ratio decreases. With the methanol compound combustion, the overal combustion duration shortened, heat is more focused and improve the combustion content. The methanol compound combustion can also recover a part of heat from the cooling system, together with the joint effect of the heat efifciency is greatly improved. However, the high methanol replacement rate wil bring the deterioration of the NOx and CO emissions with the methanol and formaldehyde emissions. The methanol compound combustion wil also delay the cylinder starts burning time, it is have to adjust the main injection timing to ensure the stable operation of the engine.

  9. Dilution effects on the controlled auto-ignition (CAI) combustion of hydrocarbon and alcohol fuels

    OpenAIRE

    Oakley, A.; Zhao, H.; Ma, T.; Ladommatos, N

    2001-01-01

    Copyright © 2001 SAE International. This paper is posted on this site with permission from SAE International. Further use of this paper is not permitted without permission from SAE This paper presents results from an experimental programme researching the in-cylinder conditions necessary to obtain homogenous CAI (or HCCI) combustion in a 4-stroke engine. The fuels under investigation include three blends of Unleaded Gasoline, a 95 RON Primary Reference Fuel, Methanol, and Ethanol. This wor...

  10. Kinetic modelling of a surrogate diesel fuel applied to 3D auto-ignition in HCCI engines

    CERN Document Server

    Bounaceur, Roda; Fournet, René; Battin-Leclerc, Frédérique; Jay, S; Da Cruz, A Pires

    2007-01-01

    The prediction of auto-ignition delay times in HCCI engines has risen interest on detailed chemical models. This paper described a validated kinetic mechanism for the oxidation of a model Diesel fuel (n-decane and α-methylnaphthalene). The 3D model for the description of low and high temperature auto-ignition in engines is presented. The behavior of the model fuel is compared with that of n-heptane. Simulations show that the 3D model coupled with the kinetic mechanism can reproduce experimental HCCI and Diesel engine results and that the correct modeling of auto-ignition in the cool flame region is essential in HCCI conditions.

  11. Determination of performance and combustion characteristics of a diesel engine fueled with canola and waste palm oil methyl esters

    Energy Technology Data Exchange (ETDEWEB)

    Ozsezen, Ahmet Necati [Department of Automotive Engineering Technology, Kocaeli University, 41380 Izmit (Turkey); Alternative Fuels R and D Center, Kocaeli University, 41040 Izmit (Turkey); Canakci, Mustafa, E-mail: canakci@kocaeli.edu.t [Department of Automotive Engineering Technology, Kocaeli University, 41380 Izmit (Turkey); Alternative Fuels R and D Center, Kocaeli University, 41040 Izmit (Turkey)

    2011-01-15

    In this study, the performance, combustion and injection characteristics of a direct injection diesel engine have been investigated experimentally when it was fueled with canola oil methyl ester (COME) and waste (frying) palm oil methyl ester (WPOME). In order to determine the performance and combustion characteristics, the experiments were conducted at constant engine speeds under the full load condition of the engine. The results indicated that when the test engine was fueled with WPOME or COME instead of petroleum based diesel fuel (PBDF), the brake power reduced by 4-5%, while the brake specific fuel consumption increased by 9-10%. On the other hand, methyl esters caused reductions in carbon monoxide (CO) by 59-67%, in unburned hydrocarbon (HC) by 17-26%, in carbon dioxide (CO{sub 2}) by 5-8%, and smoke opacity by 56-63%. However, both methyl esters produced more nitrogen oxides (NO{sub x}) emissions by 11-22% compared with those of the PBDF over the speed range.

  12. Influence of Antioxidant Addition in Jatropha Biodiesel on the Performance, Combustion and Emission Characteristics of a DI Diesel Engine

    Science.gov (United States)

    Arockiasamy, Prabu; Ramachandran Bhagavathiammal, Anand

    2017-04-01

    An experimental investigation is conducted on a single-cylinder DI diesel engine, to evaluate the performance, combustion and emission characteristics of Jatropha biodiesel with the addition of antioxidants namely, Succinimide (C4H5NO2), N,N-Dimethyl p-phenylenediamine dihydrochloride (C8H14Cl2N2) and N-Phenyl-p-phenylenediamine (C6H5NHC6H4NH2) at 500, 1000 and 2000 ppm. The performance, combustion and emission characteristic tests are conducted at a constant speed of 1500 rpm, injection pressure of 215 bar, injection timing of 26° before top dead centre for the nine test fuels and the experimental results are compared with neat diesel and neat biodiesel as base fuels. The experimental results show that the addition of antioxidant in biodiesel suppresses the NO emission by quenching the OH radicals that are produced by the reaction of hydrocarbon radicals with molecular nitrogen. The maximum percentage reduction of NO emission by 5, 6 and 7% are observed for N-Phenyl-p-phenylenediamine, N,N-Dimethyl p-phenylenediamine dihydrochloride and Succinimide blended test fuels at 2000 ppm antioxidant addition with biodiesel.

  13. A University Consortium on Low Temperature Combustion for High Efficiency, Ultra-Low Emission Engines

    Energy Technology Data Exchange (ETDEWEB)

    Assanis, Dennis N. [Univ. of Michigan, Ann Arbor, MI (United States); Atreya, Arvind [Univ. of Michigan, Ann Arbor, MI (United States); Chen, Jyh-Yuan [Univ. of California, Berkeley, CA (United States); Cheng, Wai K. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Dibble, Robert W. [Univ. of California, Berkeley, CA (United States); Edwards, Chris [Stanford Univ., CA (United States); Filipi, Zoran S. [Univ. of Michigan, Ann Arbor, MI (United States); Gerdes, Christian [Stanford Univ., CA (United States); Im, Hong [Univ. of Michigan, Ann Arbor, MI (United States); Lavoie, George A. [Univ. of Michigan, Ann Arbor, MI (United States); Wooldridge, Margaret S. [Univ. of Michigan, Ann Arbor, MI (United States)

    2009-12-31

    The objective of the University consortium was to investigate the fundamental processes that determine the practical boundaries of Low Temperature Combustion (LTC) engines and develop methods to extend those boundaries to improve the fuel economy of these engines, while operating with ultra low emissions. This work involved studies of thermal effects, thermal transients and engine management, internal mixing and stratification, and direct injection strategies for affecting combustion stability. This work also examined spark-assisted Homogenous Charge Compression Ignition (HCCI) and exhaust after-treatment so as to extend the range and maximize the benefit of Homogenous Charge Compression Ignition (HCCI)/ Partially Premixed Compression Ignition (PPCI) operation. In summary the overall goals were; Investigate the fundamental processes that determine the practical boundaries of Low Temperature Combustion (LTC) engines; Develop methods to extend LTC boundaries to improve the fuel economy of HCCI engines fueled on gasoline and alternative blends, while operating with ultra low emissions; and Investigate alternate fuels, ignition and after-treatment for LTC and Partially Premixed compression Ignition (PPCI) engines.

  14. COMBUSTION AND PERFORMANCE CHARACTERISTICS OF A SMALL SPARK IGNITION ENGINE FUELLED WITH HCNG

    Directory of Open Access Journals (Sweden)

    A. SONTHALIA

    2015-04-01

    Full Text Available Due to environmental concerns and fossil fuel depletion, large scale researches were carried out involving the use of natural gas in internal combustion engines. Natural gas is a clean burning fuel that is available from large domestic natural reserve. When it is used as a fuel in SI engines, it reduces emissions to meet EURO-III norms with carburettors and EURO-IV norms with manifold injection. Countries like India with fewer natural fossil fuel reserves depend heavily on oil imported from Middle East Asian countries and on the other hand combustion of fossil fuel has negative impact on air quality in urban areas. Use of CNG as a fuel in internal combustion engines can reduce the intensiveness of these pervasive problems. The performance of CNG can further be improved by addition of small percentages of hydrogen to it to overcome the drawbacks like lower energy density of the fuel, drop in engine power and engine out exhaust emissions. When hydrogen is added to CNG it is called as Hythane or Hydrogen enriched Compressed Natural Gas (HCNG. This can be considered as a first step towards promotion of hydrogen in automobiles. In this study, the effects of mixing hydrogen with CNG on a small air cooled four stroke SI engine’s performance, emissions and heat release rate was analyzed. A comparison of performance and emission by running engine separately on gasoline, hydrogen, CNG and HCNG was done. The results show a significant decrease in HC, CO and NOx emissions and marginal increase in specific energy consumption when fuelled with HCNG.

  15. Auto-ignition modelling: analysis of the dilution effects by the unburnt gases and of the interactions with turbulence for diesel homogeneous charge compression ignition (HCCI) engines; Modelisation de l'auto-inflammation: analyse des effets de la dilution par les gaz brules et des interactions avec la turbulence dediee aux moteurs Diesel a charge homogene

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, G.

    2005-09-15

    Homogeneous Charge Compression Ignition (HCCI) is an alternative engine combustion process that offers the potential for substantial reductions in both NO{sub x} and particulate matter still providing high Diesel-like efficiencies. Combustion in HCCI mode takes place essentially by auto-ignition. It is mainly controlled by the chemical kinetics. It is therefore necessary to introduce detailed chemistry effects in combustion CFD codes in order to properly model the HCCI combustion process. The objective of this work is to develop an auto-ignition model including detailed chemical kinetics and its interactions with turbulence. Also, a comprehensive study has been performed to analyze the chemical influence of CO and H{sub 2} residual species on auto-ignition, which can be present in the exhaust gases. A new auto-ignition model, TKI-PDF (Tabulated Kinetics for Ignition - with turbulent mixing interactions through a pdf approach) dedicated to RANS 3D engine combustion CFD calculations is proposed. The TKI-PDF model is formulated in order to accommodate the detailed chemical kinetics of auto-ignition coupled with turbulence/chemistry interactions. The complete model development and its validation against experimental results are presented in two parts. The first part of this work describes the detailed chemistry input to the model. The second part is dedicated to the turbulent mixing description. A method based on a progress variable reaction rate tabulation is used. A look-up table for the progress variable reaction rates has been built through constant volume complex chemistry simulations. Instantaneous local reaction rates inside the CFD computational cell are then calculated by linear interpolation inside the look-up table depending on the local thermodynamic conditions. In order to introduce the turbulent mixing effects on auto-ignition, a presumed pdf approach is used. The model has been validated in different levels. First, the detailed kinetic approach was

  16. A Chemical Kinetic Model of PRF Oxidation for HCCI Engine I:Comparison of existing models%适用于HCCI发动机的基础燃料化学动力学模型Ⅰ:比较现有模型

    Institute of Scientific and Technical Information of China (English)

    郑朝蕾; 张庆峰; 何祖威; 王迎

    2011-01-01

    随着HCCI燃烧技术的不断发展,燃料化学动力学机理在燃烧计算中发挥着越来越重要的作用.纵览了近年来基础燃料各种不同类型反应机理与试验研究情况,为评价现有反应机理对HCCI发动机燃烧过程的适用性,将机理模型的计算结果与HCCI燃烧相关试验进行了综合比较验证.通过4种典型基础燃料机理的计算与激波管、速压机和HCCI发动机等试验数据的比较发现,由于各反应机理构建的目的和方法不同,以及针对个别验证试验作出的参数调整,各机理在不同试验状况下性能各异,为此提出了构建适用于HCCI发动机的基础燃料简化机理的必要性.%With the development of homogenous charge compression ignition (HCCI) combustion technology, the chemical kinetic mechanism becomes more important. An review on the currently available primary reference fuels (PRF)oxidation mechanisms and experiments is discussed. The mechanisms need to be compared with experiments of HCCI combustion to evaluate the prediction in HCCI engine. Comparisons of experimental data include those from shock tube, rapid compression machine, and HCCI engine with calculated results using four typical reaction mechanisms indicate that different models from different experimental conditions are presented due to different purposes and approaches, and adjusting parameters for specified validated experiment during mechanism construction. The necessity in developing PRF reduced mechanism for HCCI combustion is addressed.

  17. The Development of a Rebust Accelerometer-Based Start of Combustion Sensing System

    Energy Technology Data Exchange (ETDEWEB)

    Jim Huang; David Mumford

    2009-01-31

    The development of modern combustion systems increasingly relies on detailed knowledge of the combustion event. As the limits of combustion are approached, tight control of combustion leads to improved emissions and higher efficiencies, while retaining and even improving engine reliability and durability. While developing a novel HCCI (Homogeneous Charge Compression Ignition) technology for large natural gas engines, Westport found that there was no reliable cost-effective technology to monitor the combustion event. As a result, Westport began working on developing a solution based on commercially available knock sensors. While initially developed around HCCI, Westport has identified that numerous other forms of combustion (high EGR systems, Homogeneous Charge Direct Injection, etc) will require combustion sensors. This requirement is also reflected in the development of other technologies in this field. However, the potential low system cost and the lack of intrusion into the cylinder head area are significant benefits for the Westport approach. Previous work by Westport has proven the method on two different large compression ignition gas engines. The objective of the current work is to improve the robustness of this technology; particularly, to identify and reduce the sensor-to-sensor and engine-to-engine variations.

  18. Numerical study of radiation effect on the municipal solid waste combustion characteristics inside an incinerator

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jingfu, E-mail: jfwang@bjut.edu.cn; Xue, Yanqing; Zhang, Xinxin; Shu, Xinran

    2015-10-15

    Highlights: • A 3-D model for the MSW incinerator with preheated air was developed. • Gas radiative properties were obtained from a statistical narrow-band model. • Non-gray body radiation model can provide more accurate simulation results. - Abstract: Due to its advantages of high degree volume reduction, relatively stable residue, and energy reclamation, incineration becomes one of the best choices for Municipal Solid Waste (MSW) disposal. However, detailed measurements of temperature and gas species inside a furnace are difficulty by conventional experimental techniques. Therefore, numerical simulation of MSW incineration in the packed bed and gas flow field was applied. In this work, a three dimensional (3-D) model of incinerator system, including flow, heat transfer, detailed chemical mechanisms, and non-gray gas models, was developed. Radiation from the furnace wall and the flame formed above the bed is of importance for drying and igniting the waste. The preheated air with high temperature is used for the MSW combustion. Under the conditions of high temperature and high pressure, MSW combustion produces a variety of radiating gases. The wavelength-depend radiative properties of flame adopted in non-gray radiation model were obtained from a statistical narrow-band model. The influence of radiative heat transfer on temperature, flow field is researched by adiabatic model (without considering radiation), gray radiation model, and non-gray radiation model. The simulation results show that taking into account the non-gray radiation is essential.

  19. Combustion Dynamic Characteristics Identification in a 9-point LDI Combustor Under Choked Outlet Boundary Conditions

    Science.gov (United States)

    He, Zhuohui J.; Chang, Clarence T.

    2017-01-01

    Combustion dynamics data were collected at the NASA Glenn Research Center's CE-5 flame tube test facility under combustor outlet choked conditions. Two 9-point Swirl-Venturi Lean Direct Injection (SV-LDI) configurations were tested in a rectangular cuboid combustor geometry. Combustion dynamic data were measured at different engine operational conditions up to inlet air pressure and temperature of 24.13 bar and 828 K, respectively. In this study, the effects of acoustic cavity resonance, precessing vortex core (PVC), and non-uniform thermal expansion on the dynamic noise spectrum are identified by comparing the dynamic data that collected at various combustor inlet conditions along with combustor geometric calculations. The results show that the acoustic cavity resonance noises were seen in the counter-rotating pilot configuration but not in the co-rotating pilot configuration. Dynamic pressure noise band at around 0.9 kHz was only detected at the P'41 location (9.8 cm after fuel injector face) but not at the P'42 location (29 cm after the fuel injector face); the amplitude of this noise band depended on the thermal expansion ratio (T4/T3). The noise band at around 1.8 kHz was found to depend on the inlet air pressure or the air density inside the combustor. The PVC frequency was not observed in these two configurations.

  20. Numerical study of radiation effect on the municipal solid waste combustion characteristics inside an incinerator.

    Science.gov (United States)

    Wang, Jingfu; Xue, Yanqing; Zhang, Xinxin; Shu, Xinran

    2015-10-01

    Due to its advantages of high degree volume reduction, relatively stable residue, and energy reclamation, incineration becomes one of the best choices for Municipal Solid Waste (MSW) disposal. However, detailed measurements of temperature and gas species inside a furnace are difficulty by conventional experimental techniques. Therefore, numerical simulation of MSW incineration in the packed bed and gas flow field was applied. In this work, a three dimensional (3-D) model of incinerator system, including flow, heat transfer, detailed chemical mechanisms, and non-gray gas models, was developed. Radiation from the furnace wall and the flame formed above the bed is of importance for drying and igniting the waste. The preheated air with high temperature is used for the MSW combustion. Under the conditions of high temperature and high pressure, MSW combustion produces a variety of radiating gases. The wavelength-depend radiative properties of flame adopted in non-gray radiation model were obtained from a statistical narrow-band model. The influence of radiative heat transfer on temperature, flow field is researched by adiabatic model (without considering radiation), gray radiation model, and non-gray radiation model. The simulation results show that taking into account the non-gray radiation is essential.

  1. Experimental investigation on NOx emission characteristics of a new solid fuel made from sewage sludge mixed with coal in combustion.

    Science.gov (United States)

    Zhai, Yunbo; Zhu, Lu; Chen, Hongmei; Xu, Bibo; Li, Caiting; Zeng, Guangming

    2015-02-01

    In this article, a new briquette fuel (SC), which was produced by the mixture of coal fines (25.9%), sewage sludge (60.6%), lignin (4.5%), tannic acid (4.5%) and elemental silicon (4.5%), was provided. Then, in a high temperature electric resistance tubular furnace, the total emissions of NO2 and NO, effects of combustion temperature, air flow rate and heating rate on NOx (NO, NO2) emissions of SC were studied during the combustion of SC; furthermore, effects of additives on hardness were also analysed, and the X-ray photoelectron spectroscopy was applied to investigate the reduced NOx emission mechanism. The research results showed that, compared with the characteristics of briquette fuel (SC0) produced only by the mixture of coal and sewage sludge (the ratio of coal to sewage sludge was the same as that of SC), the Meyer hardness of SC was 12.6% higher than that of SC0 and the emissions of NOx were 27.83% less than that of SC0 under the same combustion conditions. The NOx emissions of SC decreased with the adding of heating rate and increased with the rise of air flow rate. When the temperature was below 1000 °C, the emissions of NOx increased with the elevated temperature, however, further temperature extension will result in a decreasing in emissions of NOx. Furthermore, the X-ray photoelectron spectroscopy results proposed that the possible mechanism for the reduction of NOx emissions was nitrogen and silicon in SC to form the compounds of silicon and nitrogen at high temperatures.

  2. Evaluation of in-cylinder mixture homogeneity in a diesel HCCI engine – A CFD analysis

    Directory of Open Access Journals (Sweden)

    N. Ramesh

    2016-06-01

    Full Text Available Performance and emission characteristics of HCCI engines depend on achieving a good in-cylinder homogeneous mixture. The formation of in-cylinder mixture depends on many engine parameters, which need optimization. In addition, as of now, there is no direct way to clearly describe and estimate in-cylinder mixture homogeneity. In the CFD analysis, it is evaluated indirectly using contour plots of equivalence ratio, variation of in-cylinder pressure with crank angles, heat release curves or by the comparison of emissions. In this study, an attempt has been made to develop methods to evaluate the in-cylinder mixture homogeneity by the CFD analysis using AVL-FIRE. Here, global and local in-cylinder fuel distribution and in-cylinder fuel distribution index are used to evaluate the mixture homogeneity. In order to evaluate these methods, mixture homogeneities in two cases of fuel injections with 7- and 10-hole injector are compared. Finally, we found that the global fuel distribution (GFD plot helps direct quantitative assessment of mixture distribution in various ER range. However, the GFD method cannot explain the spatial variation of fuel distribution and does not provide mixture homogeneity on a simple scale. In the method of plotting fuel distribution index, the overall homogeneity will be evaluated on a scale of 0 to 1 by a simple way. In the method of plotting local fuel distribution (LFD, the spatial variation of mixture homogeneity is well defined in local zones both in radial and axial directions. Further, these proposed methods help us to reduce the computation time significantly.

  3. 城市垃圾典型组分燃烧特性研究%Study on Combustion Characteristics of Municipal Solid Waste

    Institute of Scientific and Technical Information of China (English)

    刘效洲

    2011-01-01

    本文首先分析了垃圾燃烧存在的问题,再介绍垃圾燃烧特性的热重分析原理和燃烧特性参数的确定方法.对十种工况的垃圾燃烧进行分析,通过试验得出各组分的TGA和DTGA曲线及其燃烧特征参数.经研究发现混合组分垃圾的燃烧过程具有分步性,其活化能低于单组分垃圾,比单一组分垃圾更易燃烧;混合垃圾的燃烧特性并没有发生显著变化,可以近似用单组分垃圾的燃烧特性来估计,这一结论对于垃圾焚烧炉的设计有一定的指导意义.%This paper introduced the shortcomings of combustion of municipal solid waste, the principle of TGA analysis in the combustion characteristics of municipal solid waste and the method for determining the combustion parameters. The working conditions of combustion of municipal solid waste was analysed through experiments obtaining the componerts TGA, DTGA and the combustion characteristics parameters.The results shows that the burning process of the unclassified garbage displays multi - stage feature; the activation energy of the tmclassified garbage is lower than that of the single - ingredient garbage and the unclassified garbage is more apt to burn than the single - ingredient garbage. Moreover, combustion characteristics of the unclassified garbage are similar to those of the single - ingredient garbage, so its combustion characteristics can be estimated by the combination of various single - ingredient garbage. This conclusion will be of certain reference value in the design of garbage incinerator.

  4. Experimental and analytical investigation on the emission and combustion characteristics of CI engine fueled with tamanu oil methyl esters

    Directory of Open Access Journals (Sweden)

    Perumal Navaneetha Krishnan

    2016-01-01

    Full Text Available The emission and combustion characteristics of a four stroke multi fuel single cylinder variable compression ratio engine fueled with tamanu oil methyl ester and its blends 10%, 20%, 40%, and 60% with diesel (on volume basis are examined and compared with standard diesel. Biodiesel produced from tamanu oil by trans-esterification process has been used in this study. The experiment has been conducted at a constant engine speed of 1500 rpm with 50% load and at compression ratios of 16:1, 17:1, 18:1, 19:1, and 20:1. With different blend and for selected compression ratio the exhaust gas emissions such as CO, HC, NOx, CO2, and the combustion characteristics are measured. The variation of the emission parameters for different compression ratios and for different blends is given, and optimum compression ratio which gives best performance has been identified. The results indicate higher rate of pressure rise and minimum heat release rate at higher compression ratio for tamanu oil methyl ester when compared with standard diesel. The blend B40 for tamanu oil methyl ester is found to give minimum emission at 50% load. The blend when used as fuel results in reduction of polluting gases like HC, CO, and increase in NOx emissions. The previously mentioned emission parameters have been validated with the aid of artificial neural network. A separate model is developed for emission characteristics in which compression ratio, blend percentage and load percentage were used as the input parameter whereas CO, CO2, HC, and NOx were used as the output parameter. This study shows that there is a good correlation between the artificial neural network predicted values and the experimental data for different emission parameters.

  5. PERFORMANCE, EMISSION, AND COMBUSTION CHARACTERISTICS OF A CI ENGINE USING LIQUID PETROLEUM GAS AND NEEM OIL IN DUAL FUEL MODE

    Directory of Open Access Journals (Sweden)

    Palanimuthu Vijayabalan

    2010-01-01

    Full Text Available Increased environmental awareness and depletion of resources are driving the industries to develop viable alternative fuels like vegetable oils, compresed natural gas, liquid petroleum gas, producer gas, and biogas in order to provide suitable substitute to diesel for compression ignition engine. In this investigation, a single cylinder, vertical, air-cooled diesel engine was modified to use liquid petroleum gas in dual fuel mode. The liquefied petroleum gas, was mixed with air and supplied through intake manifold. The liquid fuel neem oil or diesel was injected into the combustion chamber. The performance, emission, and combustion characteristics were studied and compared for neat fuel and dual fuel mode. The experimental results on dual fuel engine show a reduction in oxides of nitrogen up to 70% of the rated power and smoke in the entire power range. However the brake thermal efficiency was found decreased in low power range due to lower calorific value of liquid petroleum gas, and increase in higher power range due to the complete burning of liquid petroleum gas. Hydrocarbon and carbon monoxide emissions were increased significantly at lower power range and marginal variation in higher power range.

  6. Chemical, structural and combustion characteristics of carbonaceous products obtained by hydrothermal carbonization of palm empty fruit bunches.

    Science.gov (United States)

    Parshetti, Ganesh K; Kent Hoekman, S; Balasubramanian, Rajasekhar

    2013-05-01

    A carbon-rich solid product, denoted as hydrochar, was synthesized by hydrothermal carbonization (HTC) of palm oil empty fruit bunch (EFB), at different pre-treatment temperatures of 150, 250 and 350 °C. The conversion of the raw biomass to its hydrochar occurred via dehydration and decarboxylation processes. The hydrochar produced at 350 °C had the maximum energy-density (>27 MJ kg(-1)) with 68.52% of raw EFB energy retained in the char. To gain a detailed insight into the chemical and structural properties, carbonaceous hydrochar materials were characterized by FE-SEM, FT-IR, XRD and Brunauer-Emmett-Teller (BET) analyses. This work also investigated the influence of hydrothermally treated hydrochars on the co-combustion characteristics of low rank Indonesian coal. Conventional thermal gravimetric analysis (TGA) parameters, kinetics and activation energy of different hydrochar and coal blends were estimated. Our results show that solid hydrochars improve the combustion of low rank coals for energy generation.

  7. HCCI Misfire Control Based on Ion Current Integral Signal%基于离子电流积分信号的HCCI失火控制

    Institute of Scientific and Technical Information of China (English)

    张栖玉; 张志永; 李从跃; 李理光

    2011-01-01

    A test bench for HCCI gasoline engine is built, in which the proper parameters of ion current detection system and its signal integral circuit are determined through tests. The features of ion current integral signal and its correlation with combustion are then analyzed. Finally an experimental study is conducted for the misfire cycle of HCCI engine in low-speed light load condition on the closed-loop control of in-cycle re-ignition based on ion current integral signal feedback. The results show that ion current integral signal can be taken as misfire criterion, and in-cycle re-ignition can effectively ignite mixture and hence reduce HC emission.%搭建了HCCI汽油机试验台,并通过试验为其离子电流检测系统及其信号积分电路选定合适的参数.分析了不同燃烧工况下的离子电流积分信号特征及其与燃烧的相关性,最后对低速小负荷工况HCCI失火循环进行了基于离子电流积分信号反馈的循环内补火闭环控制的试验研究,结果表明,离子电流积分信号可作为失火的判断标准,而循环内补火可有效地引燃混合气,降低HC排放.

  8. Evaluation of Closed-Loop Control Strategy of HCCI/SI Gasoline Engine in Driving Cycles%HCCI/SI复合模式汽油机闭环控制策略的整车驾驶循环评估

    Institute of Scientific and Technical Information of China (English)

    谢辉; 李楠; 周能辉; 赵华

    2008-01-01

    HCCI燃烧应用于实际车辆,面临燃烧闭环控制、动态过程控制及HCCI/SI模式过渡控制等难点问题.本文针对这些问题展开研究,基于GT-power软件建立了四缸HCCI/SI复合模式汽油机模型及轿车动力学模型,采用Simulink软件建立了HCCI/SI复合模式汽油机分层闭环控制器.通过典型驾驶过程以及NEDC循环的仿真,对HCCI/SI发动机闭环控制器的动态控制能力和模式切换控制能力进行了研究,详细考察了HCCI/SI复合模式汽油机轿车的燃油经济性的改善效果.仿真结果表明,HCCI/SI复合模式汽油机及其控制器可以实现驾驶过程中HCCI与SI模式的比较平滑的过渡,满足车辆行驶的动力需求,并显示出良好的经济性,在整个NEDC循环中比原机节油12.2%.

  9. GESTIS-STAUB-EX - combustion and explosion characteristics of dusts on the internet; GESTIS-STAUB-EX - Brenn- und Explosionskenngroessen von Staeuben im Internet

    Energy Technology Data Exchange (ETDEWEB)

    Beck, H. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany)

    2001-03-01

    Since 1980, the Berufsgenossenschaftliches Institut fuer Arbeitssicherheit - BIA has been publishing combustion and explosion characteristics of dusts in tabular form. The data were determined by various test bodies using harmonised methods and test facilities. At the time being, combustion and explosion data for more than 4000 dusts are available. From February 2001 these data may be accessed via Internet, address: www.hvbg.de/BIA/GESTIS-STAUB-EX. To use the data correctly, it is essential to have knowledge of the different factors - e.g. fineness and humidity of the dusts - which have an effect on the characteristics, and to observe the limits of applicability. (orig.)

  10. HYDROGEN ADDITION ON COMBUSTION AND EMISSION CHARACTERISTICS OF HIGH SPEED SPARK IGNITION ENGINE- AN EXPERIMENTAL STUDY

    Directory of Open Access Journals (Sweden)

    SHIVAPRASAD K. V.

    2016-11-01

    Full Text Available The present article aims at characterizing the combustion and emission parameters of a single cylinder high speed SI engine operating with different concentrations of hydrogen with gasoline fuel. The conventional carburetted SI engine was modified into an electronically controllable engine, wherein ECU was used to control the injection timings and durations of gasoline. The engine was maintained at a constant speed of 3000 rpm and wide open throttle position. The experimental results demonstrated that heat release rate and cylinder pressure were increased with the addition of hydrogen until 20%. The CO and HC emissions were reduced considerably whereas NOx emission was increased with the addition of hydrogen in comparison with pure gasoline engine operation.

  11. PREDICTION OF COMBUSTION CHARACTERISTICS OF A TYPICAL BIOGAS BURNER USING CFD

    Directory of Open Access Journals (Sweden)

    K. MADHUSOODAN PILLAI

    2012-07-01

    Full Text Available Biogas is obtained from anaerobic digestion of biodegradable materials such as agricultural waste, animal waste, and othertype of household solid waste and its main constituents are CH4 and CO2. Effects of the concentration of each species are very important in the biogas combustion. The present study focuses on the effect of inlet velocities of methane and air on the flame temperature in a biogas burner lamp. The model of biogas burner lamp is constructed by using the CFD software GAMBIT and the simulation process was performed by using Fluent Software. The flame temperature obtained is 2172 k when the inlet velocities of methane and air are 0.2m/s and 0.8 m/s respectively. Results of this study will provide valuable data for biogas burner lamp manufacturers.

  12. Experimental study of combustion characteristics of isolated pockets of hydrogen-air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Manoubi, M.; LaFleche, M. [Univ. of Ottawa, Dept. of Mechanical Engineering, Ottawa, Ontario (Canada); Liang, Z., E-mail: zhe.liang@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Radulescu, M. [Univ. of Ottawa, Dept. of Mechanical Engineering, Ottawa, Ontario (Canada)

    2016-06-15

    This paper examines the dynamics of unconfined hydrogen-air flames and the criterion for flame propagation between neighbouring pockets of reactive gas separated by air using the soap bubble technique. The combustion events were visualized using high-speed schlieren or large-scale shadowgraph systems. It was revealed that for sufficiently lean hydrogen-air mixtures characterized by low flame speeds, buoyancy effects become important at small scales. The critical radius of hemispherical flame that will rise due to buoyancy is highly sensitive to the hydrogen concentration. The test results demonstrate that for transition of a flame between neighbouring pockets, the separation distance between the bubbles is mainly determined by the expansion ratio for near stoichiometric mixture, but it becomes much smaller for leaner mixtures because the flame kernel rises due to buoyant effects before the flame can reach the second bubble, thus the separation distance is no longer governed by the expansion ratio. (author)

  13. The first operation and combustion characteristics of 1MW{sub th} test facility

    Energy Technology Data Exchange (ETDEWEB)

    Jang, G.H.; Chang, I.G.; Jeong, S.Y.; Seon, C.Y.; Yang, G.M. [R and D Center, Hanjung, Changwon (Korea)

    1998-11-01

    In this study, the effects of air staging with different parameter variations were investigated on their NOx emission and burnout of fuel. For this purpose, a pulverized coal combustion test facility with 1MW{sub th} was available. The burner of combustor was externally air staging burner(EASE) type made by IFRF. The pulverized high bituminous(Blair athol) coal from Australia was used as fuel, and the particle size less than 80 {mu}m was 83.4%. Overall excess air ratio was 1.2. From the study, the amount of core air did not affect their NOx reduction. With fuel rich condition in primary zone, the NOx emission was improved. But it was not possible to achieve a sufficient burnout when NOx emission was less than 500 ppm. (author). 8 refs., 8 figs., 2 tabs.

  14. Physical and chemical characteristics of cenospheres from the combustion of heavy fuel oil

    Science.gov (United States)

    Clayton, R. M.; Back, L. H.

    1989-01-01

    Photomicrography of particle cross sections, measurements of density, porosity, and surface area, and determinations of chemical compositions, have been used in conjunction with SEM of surface structure to characterize cenospheres generated by combustion of residual oil in a steam power plant. Large and small cenospheres, which respectively fall into the 100-200 and small 20-40 micron range, are spheroidal and hollow, with at least one blowhole; outer/inner diameter ratios for the shells are of the order of 1.3-1.4. Typically, a cenosphere contains only about 18 vol pct solid material. The presence of S, Fe, Na, and V in substantial concentrations presage high temperature heat exchanger surface corrosion problems due to cenosphere deposition.

  15. Combustion characteristics of pulverized coal and air/gas premixed flame in a double swirl combustor

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, M.M. [Ain Shams University, Cairo (Egypt). Faculty of Education

    2009-07-01

    An experimental work was performed to investigate the co-firing of pulverized coal and premixed gas/air streams in a double swirl combustor. The results showed that the NOx emissions are affected by the relative rates of thermal NOx formation and destruction via the pyrolysis of the fuel-N species in high temperature fuel-rich zones. Various burner designs were tested in order to vary the temperature history and the residence time across both coal and gas flames inside the furnace. It was found that by injecting the coal with a gas/air mixture as a combined central jet surrounded by a swirled air stream, a double flame envelope develops with high temperature fuel-rich conditions in between the two reaction zones such that the pyrolysis reactions to N{sub 2} are accelerated. A further reduction in the minimum NOx emissions, as well as in the minimum CO concentrations, was reported for the case where the coal particles are fed with the gas/air mixture in the region between the two swirled air streams. On the other hand, allocating the gas/air mixture around the swirled air-coal combustion zone provides an earlier contact with air and retards the NOx reduction mechanism in such a way that the elevated temperatures around the coal particles allow higher overall NOx emissions. The downstream impingement of opposing air jets was found more efficient than the impinging of particle non-laden premixed flames for effective NOx reduction. In both cases, there is an upstream flow from the stagnation region to the coal primary combustion region, but with the case of air impingement, the hot fuel-rich zone develops earlier. The optimum configuration was found by impinging all jets of air and coal-gas/air mixtures that pronounced minimum NOx and CO concentrations of 310 and 480ppm, respectively.

  16. Experimental Investigation into the Combustion Characteristics on the Co-firing of Biomass with Coal as a Function of Particle Size and Blending Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Lkhagvadorj, Sh; Kim, Sang In; Lim, Ho; Kim, Seung Mo; Jeon, Chung Hwan [Pusan National Univ., Busan (Korea, Republic of); Lee, Byoung Hwa [Doosan Heavy Industries and Construction, Ltd., Changwon (Korea, Republic of)

    2016-01-15

    Co-firing of biomass with coal is a promising combustion technology in a coal-fired power plant. However, it still requires verifications to apply co-firing in an actual boiler. In this study, data from the Thermogravimetric analyzer(TGA) and Drop tube furnace(DTF) were used to obtain the combustion characteristics of biomass when co-firing with coal. The combustion characteristics were verified using experimental results including reactivity from the TGA and Unburned carbon(UBC) data from the DTF. The experiment also analyzed with the variation of the biomass blending ratio and biomass particle size. It was determined that increasing the biomass blending ratio resulted in incomplete chemical reactions due to insufficient oxygen levels because of the rapid initial combustion characteristics of the biomass. Thus, the optimum blending condition of the biomass based on the results of this study was found to be 5 while oxygen enrichment reduced the increase of UBC that occurred during combustion of blended biomass and coal.

  17. An investigation into physicochemical characteristics of ash produced from combustion of oil palm biomass wastein a boiler

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Chun Yang; Kadir, Sharifah Aishah Syed Abdul; Lim, Ying Pei; Syed-Ariffin, Sharifah Nawirah; Zamzuri, Zurinawati [Faculty of Chemical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2008-07-15

    Ash derived from combustion of Malaysian oil palm biomass (empty fruit bunches consisting of fibers) was physically and chemically characterized in order to provide a comprehensive understanding of its specific properties in terms of toxicity, compositions and reusability. Principal analyses conducted include particle size distribution, scanning electron microscopy, elemental dispersive X-ray, elemental analysis, toxicity characteristic leaching procedure (TCLP) as well as thermogravimetric, X-ray diffractometry and Fourier-transform infrared analyses. TCLP result indicated that the oil palm ash (OPA) should not be classified as toxic wastes in terms of heavy metal leachability since leachable copper, cadmium, lead and nickel concentrations were detected below the stipulated leachability limits. It was determined that the OPA contained high amount of potassium as well as presence of silica which implied its suitability to be reused as crude fertilizer or cement replacement material. (author)

  18. Structural, electrical and magnetic characteristics of nickel substituted cobalt ferrite nano particles, synthesized by self combustion method

    Science.gov (United States)

    Sontu, Uday Bhasker; Yelasani, Vijayakumar; Musugu, Venkata Ramana Reddy

    2015-01-01

    Nickel-substituted cobalt ferrite nano-particles are synthesized using a self-combustion method. Aqueous metal nitrates and citric acid form the precursors. No external oxidizing agents are used to change the pH of the precursors; this resulted in a more environment friendly synthesis. Structural, magnetic and electrical characteristics of the nano ferrites are verified using X-ray diffractometer (XRD), VSM and impedance analyzer respectively. Phase formation, particle size, lattice parameter, X-ray density, saturation magnetization, coercivity, dielectric constant and electrical activation energy as function of nickel substitution in cobalt ferrite are studied. It is shown here that the magnetic and electrical properties can be tuned by varying the nickel concentration.

  19. Analysis of fuel spray characteristics for premixed lean diesel combustion; Kihaku yokongo diesel kikan ni okeru nenryo funmu kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, S.; Harada, a.; Miyamoto, T.; Akagawa, H.; Tsujimura, K.

    1997-10-01

    Premixed lean diesel combustion (PREDIC) makes it possible to achieve low NOx emission. It is an important factor to make the homogeneous spray formation for PREDIC. In this paper presents I the effect of the spray dispersion on emission characteristic were analyzed with the spray observation and engine test. Pintle type nozzle, which has different feature from orifice type nozzle, are used to form the hollow cone spray. As a result, the pintle type nozzle having grooves to generate the swirl flow, makes the reduced penetration in comparison with the hole nozzle under low ambient gas pressure. And it could improve THC, CO emissions at low NOx emission condition. 7 refs., 12 figs., 1 tab.

  20. Effectiveness of oxygen enriched hydrogen-HHO gas addition on DI diesel engine performance, emission and combustion characteristics

    Directory of Open Access Journals (Sweden)

    Premkartikkumar S.R.

    2014-01-01

    Full Text Available Nowadays, more researches focus on protecting the environment. Present investigation concern with the effectiveness of Oxygen Enriched hydrogen- HHO gas addition on performance, emission and combustion characteristics of a DI diesel engine. Here the Oxygen Enriched hydrogen-HHO gas was produced by the process of water electrolysis. When potential difference is applied across the anode and cathode electrodes of the electrolyzer, water is transmuted into Oxygen Enriched hydrogen-HHO gas. The produced gas was aspirated into the cylinder along with intake air at the flow rates of 1 lpm and 3.3 lpm. The results show that when Oxygen Enriched hydrogen-HHO gas was inducted, the brake thermal efficiency of the engine increased by 11.06%, Carbon monoxide decreased by 15.38%, Unburned hydrocarbon decreased by 18.18%, Carbon dioxide increased by 6.06%, however, the NOX emission increased by 11.19%.

  1. NOx and N{sub 2}O emission characteristics from fluidised bed combustion of semi-dried municipal sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Saenger, M.; Werther, J.; Ogada, T. [Technical University Hamburg-Harburg, Hamburg (Germany). Chemical Engineering

    2001-01-01

    Incineration is one of the major methods for the disposal of sewage sludge. Currently, several plants are incinerating mechanically dewatered (wet) sludge (20-40 wt.% d.m.) or semi-dried sewage sludge (3-55 wt.% d.m.), although some plants burn dry sludge (with more than 80 wt.% d.m.). Whereas significant information is available on NOx and N{sub 2}O emissions characteristics of wet and dry sludge, not much has been reported on semi-dried sludge. This paper presents some of the results obtained from the combustion of semi-dried sludge in a semi-pilot scale fluidised bed combustor (150 mm in diameter and 9 m high) together with some measurements from a large-scale FBC incineration plant (7 m{sup 2} bed area, 9 m high and a capacity of 3 t/h dry sludge). The investigations have shown that semi-dried sludge exhibit emission characteristics which are similar to those of wet sludge. NOx decreases slightly whereas N{sub 2}O remains more or less the same with increase in oxygen concentrations. Just like wet sludge, staged combustion was not effective for the reduction of NOx and N{sub 2}O. However, increasing the freeboard temperature led to rapid reduction of N{sub 2}O and some NOx reduction was achieved using flue gas recycling technique. Comparison shows that the results from the test rig were more or less similar to those obtained from the large-scale plants. 28 refs., 14 figs., 2 tabs.

  2. Combustion and Emission Characteristics of Variable Compression Ignition Engine Fueled with Jatropha curcas Ethyl Ester Blends at Different Compression Ratio

    Directory of Open Access Journals (Sweden)

    Rajneesh Kumar

    2014-01-01

    Full Text Available Engine performance and emission characteristics of unmodified biodiesel fueled diesel engines are highly influenced by their ignition and combustion behavior. In this study, emission and combustion characteristics were studied when the engine operated using the different blends (B10, B20, B30, and B40 and normal diesel fuel (B0 as well as when varying the compression ratio from 16.5 : 1 to 17.5 : 1 to 18.5 : 1. The change of compression ratio from 16.5 : 1 to 18.5 : 1 resulted in 27.1%, 27.29%, 26.38%, 28.48%, and 34.68% increase in cylinder pressure for the blends B0, B10, B20, B30, and B40, respectively, at 75% of rated load conditions. Higher peak heat release rate increased by 23.19%, 14.03%, 26.32%, 21.87%, and 25.53% for the blends B0, B10, B20, B30, and B40, respectively, at 75% of rated load conditions, when compression ratio was increased from16.5 : 1 to 18.5 : 1. The delay period decreased by 21.26%, CO emission reduced by 14.28%, and NOx emission increased by 22.84% for B40 blends at 75% of rated load conditions, when compression ratio was increased from 16.5 : 1 to 18.5 : 1. It is concluded that Jatropha oil ester can be used as fuel in diesel engine by blending it with diesel fuel.

  3. New Combustion Technology on Homogeneous Charge Compression Ignition%均质压燃在内燃机燃烧技术中的应用

    Institute of Scientific and Technical Information of China (English)

    周晶磊; 夏鸿文; 任超伟

    2013-01-01

    均质压燃(HCCI)是一种新的燃烧方式,它是预混混合气在压缩过程中温度升高达到自燃温度以后发生的燃烧现象。本文阐述了“均质压燃、低温燃烧”新一代内燃机燃烧技术的背景、研究现状以及所取得的主要研究进展。%With the rapid development of national economy, there are a lot of automobiles in China. The main power devices of automobiles are internal combustion engines, which faces more challenges, such as energy saving and environmental protection. But these challenges are advantageous to improve automo-tive technologies and spur a new generation, energy saving and low emission cars to appear. HCCI (Homo-geneous Charge Compression Ignition) is a new kind of combustion mode, which is the autoignition of pre-mixtures when their temperature is high enough to self-ignition by compression. This combustion can reduce the emission of NOX and particulate matters, in addition, use many fuel, so HCCI has been a research hot spot in internal combustion engine field.This paper focuses on the background, the technical route and the key scientific advances and achievements of new combustion technology on the Homogeneous Charge Compression Ignition (HCCI) .

  4. Improvement of lean combustion characteristics of heavy-hydrocarbon fuels with hydrogen addition; Suiso tenka ni yoru kokyu tanka suisokei nenryo no kihaku nensho no kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Y. [Saitama Institute of Technology, Saitama (Japan); Ishizuka, S. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

    1999-09-25

    The Lewis numbers of lean heavy-hydrocarbon fuels are larger than unity, and hence, their flames are prone to extinction in a shear flow, which occurs in a turbulent combustion. Here, propane is used as a representative fuel of heavy-hydrocarbon fuels because the Lewis number of lean propane/air mixtures is larger than unity, and an attempt to improve its combustion characteristics by hydrogen addition has been made. A tubular flame burner is used to evaluate its improvement, since a rotating, stretched vortex flow is established in the burner. The results show that with' hydrogen addition, the fuel concentration, the flame diameter and the flame temperature at extinction are reduced and its combustion characteristics are improved. However, it is found that the effective equivalence ration at extinction cannot become so small as that of lean methane/air mixture, which has a Lewis number less than unity. (author)

  5. INVESTIGATION OF COMBUSTION, PERFORMANCE AND EMISSION CHARACTERISTICS OF SPARK IGNITION ENGINE FUELLED WITH BUTHANOL – GASOLINE MIXTURE AND A HYDROGEN ENRICHED AIR

    Directory of Open Access Journals (Sweden)

    Alfredas Rimkus

    2016-09-01

    Full Text Available In this study, spark ignition engine fuelled with buthanol-gasoline mixture and a hydrogen-enriched air was investigated. Engine performance, emissions and combustion characteristics were investigated with different buthanol (10% and 20% by volume gasoline mixtures and additionally supplied oxygen and hydrogen (HHO gas mixture (3.6 l/min in the sucked air. Hydrogen, which is in the HHO gas, improves gasoline and gasoline-buthanol mixture combustion, increases indicated pressure during combustion phase and decreases effective specific fuel consumption. Buthanol addition decreases the rate of heat release, the combustion temperature and pressure are lower which have an influence on lower nitrous oxide (NOx emission in exhaust gases. Buthanol lowers hydrocarbon (HC formation, but it increases carbon monoxide (CO concentration and fuel consumption. Combustion process analysis was carried out using AVL BOOST software. Experimental research and combustion process numerical simulation showed that using balanced buthanol and hydrogen addition, optimal efficient and ecological parameters could be achieved when engine is working with optimal spark timing, as it would work on gasoline fuel.

  6. 火灾试验用标准燃烧物的制备及燃烧特性%Preparation and combustion characteristic of standard combustible materials used for fire test

    Institute of Scientific and Technical Information of China (English)

    宋波; 李毅; 韩伟平; 刘欣; 田立伟

    2013-01-01

    Typical plastic-cup and paper-cup standard combustible material have been prepared based on fire load density and material composition of the typical places.Experimental research on these 2 combustible materials' combustion characteristic shows that:their combustion properties are stable,total heat release and fire growth rate have small deviation,and the tests have good reproducibility.Under certain conditions,plastic-cup standard combustible material can represent quasi medium fire with fire load of 157.8 MJ,and paper-cup standard combustible material can represent slow fire with fire load of 51.1 MJ.%基于典型场所的火灾载荷密度及可燃物,制备了典型的塑料杯组合体和纸杯组合体标准燃烧物,开展两种标准燃烧物的燃烧特性试验研究.结果表明,两种典型的标准燃烧物的燃烧性能稳定,总热值、火灾增长速率数据偏差较小,实验的重现性良好;在一定条件下,塑料杯组合体标准燃烧物可近似代表火灾载荷约为157.8 MJ的近中速火,纸杯组合体标准燃烧物可近似代表火灾载荷约为51.1 MJ的慢速火.

  7. Chemical Kinetics of Hydrocarbon Ignition in Practical Combustion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C.K.

    2000-07-07

    Chemical kinetic factors of hydrocarbon oxidation are examined in a variety of ignition problems. Ignition is related to the presence of a dominant chain branching reaction mechanism that can drive a chemical system to completion in a very short period of time. Ignition in laboratory environments is studied for problems including shock tubes and rapid compression machines. Modeling of the laboratory systems are used to develop kinetic models that can be used to analyze ignition in practical systems. Two major chain branching regimes are identified, one consisting of high temperature ignition with a chain branching reaction mechanism based on the reaction between atomic hydrogen with molecular oxygen, and the second based on an intermediate temperature thermal decomposition of hydrogen peroxide. Kinetic models are then used to describe ignition in practical combustion environments, including detonations and pulse combustors for high temperature ignition, and engine knock and diesel ignition for intermediate temperature ignition. The final example of ignition in a practical environment is homogeneous charge, compression ignition (HCCI) which is shown to be a problem dominated by the kinetics intermediate temperature hydrocarbon ignition. Model results show why high hydrocarbon and CO emissions are inevitable in HCCI combustion. The conclusion of this study is that the kinetics of hydrocarbon ignition are actually quite simple, since only one or two elementary reactions are dominant. However, there are many combustion factors that can influence these two major reactions, and these are the features that vary from one practical system to another.

  8. The study on the heat transfer characteristics of oxygen fuel combustion boiler

    Science.gov (United States)

    Wu, Haibo; Liu, Zhaohui; Liao, Haiyan

    2016-10-01

    According to 350MW and 600MW boilers, under oxygen fuel condition, through the reasonable control of the primary and secondary flow and the correct option and revision of mathematical model, the temperature distribution, heat flux distribution and absorption heat distribution, etc. was obtained which compared with those under air condition. Through calculation, it is obtained that the primary and secondary flow mixed well, good tangentially fired combustion in furnace was formed, the temperature under air condition obviously higher than the temperature under O26 condition. The adiabatic flame temperature of wet cycle was slightly higher than that of dry cycle. The maximum heat load appeared on the waterwall around the burner area. The heat load gradually decreased along the furnace height up and down in burner area. The heat absorption capacity of the furnace under O26 was lower than that under the air condition. The heat absorption capacity of the platen heating surface under O26 was equal to that under air condition. And the heat absorbing capacity of waterwall under O26 was about7%~12% less than that under air condition.

  9. Performance and combustion characteristics of a direct injection SI hydrogen engine

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Ali [Engine Technology, Powertrain, Toyota Motor Europe, Technical centre Hoge Wei 33 Zaventem 1930 (Belgium); Shioji, Masahiro; Nakai, Yasuyuki; Ishikura, Wataru [Graduate School of Energy Science, Kyoto University, Yoshida-honmachi Sakyo-ku Kyoto 605-8501 (Japan); Tabo, Eizo [Environmental and Technical Affairs Department, Mitsubishi Motors Co., 5-33-8 Shiba Minatoku Tokyo 108-8401 (Japan)

    2007-02-15

    Hydrogen with low spark-energy requirement, wide flammability range and high burning velocity is an important candidate for being used as fuel in spark-ignition engines. It also offers CO{sub 2} and HC free combustion and lean operation resulting in lower NO{sub x} emissions. However, well examined external mixing of hydrogen with intake air causes backfire and knock especially at higher engine loads. In addition, low heating value per unit of volume of hydrogen limits the maximum output power. In this study, attention was paid to full usage of hydrogen advantage employing internal mixing method. Hydrogen was directly injected into cylinder of a single-cylinder test engine using a high-pressure gas injector and effects of injection timing and spark timing on engine performance and NO{sub x} emission were investigated under wide engine loads. The results indicate that direct injection of hydrogen prevents backfire, and that high thermal efficiency and output power can be achieved by hydrogen injection during late compression stroke. Moreover, by further optimization of the injection timing for each engine load, NO{sub x} emission can be reduced under the high engine output conditions. (author)

  10. Combustion characteristics and turbulence modeling of swirling reacting flow in solid fuel ramjet

    Science.gov (United States)

    Musa, Omer; Xiong, Chen; Changsheng, Zhou

    2017-10-01

    This paper reviews the historical studies have been done on the solid-fuel ramjet engine and difficulties associated with numerical modeling of swirling flow with combustible gases. A literature survey about works related to numerical and experimental investigations on solid-fuel ramjet as well as using swirling flow and different numerical approaches has been provided. An overview of turbulence modeling of swirling flow and the behavior of turbulence at streamline curvature and system rotation are presented. A new and simple curvature/correction factor is proposed in order to reduce the programming complexity of SST-CC turbulence model. Finally, numerical and experimental investigations on the impact of swirling flow on SFRJ have been carried out. For that regard, a multi-physics coupling code is developed to solve the problems of multi-physics coupling of fluid mechanics, solid pyrolysis, heat transfer, thermodynamics, and chemical kinetics. The connected-pipe test facility is used to carry out the experiments. The results showed a positive impact of swirling flow on SFRJ along with, three correlations are proposed.

  11. Expansion characteristics of twin combustion gas jets with high pressure in cylindrical filling liquid chamber

    Institute of Scientific and Technical Information of China (English)

    薛晓春; 余永刚; 张琦

    2013-01-01

    To deal with the problem of how to control the interior ballistic stability in the bulk-loaded liquid propellant gun, the expansion and mixing process of the twin combustion-gas jets with high temperature and pressure in a liquid medium is studied in the cylindrical filling liquid chamber. A series of the jet expansion shapes is obtained by using a high-speed photographic system. The influences of the jet pressure on the jet expansion shape are discussed. Based on the experiments, the three-dimensional mathematical model is established. The expansion processes of the twin gas jets in the liquid medium are simulated by means of fluent to get the pressure, density, temperature, velocity contours and evolutionary process of vortices. Results show that the jet external outline and tops are all irregular. The Kelvin-Helmholtz instability is shown in the whole expansion process. The numerical simulation results of the axial displacement of the twin gas jets in liquid agree well with the experiment.

  12. Characteristics of Hydrogen Storage Alloy Mg2Ni Produced by Hydriding Combustion Synthesis

    Institute of Scientific and Technical Information of China (English)

    Qian LI; Qin LIN; Lijun JIANG; Kou-chih CHOU; Feng ZHAN; Qiang ZHENG

    2004-01-01

    A high activity and large capacity of hydrogen storage alloy Mg2Ni by hydriding combustion synthesis was investigatedby means of pressure composition isotherms, X-ray diffraction and scanning electron microscopy. The results showedthat the maximum hydrogen absorption capacity of Mg2Ni is 3.25 mass fraction at 523 K, just after synthesis withoutany activation. The relationships between the equilibrium plateau pressure and the temperature for Mg2Ni were lgp(0.1 Mpa)=3026/T+5.814 (523 K≤ T ≤623 K) for hydriding and Igp (0.1 Mpa)=-3613/T+6.715 (523 K≤T ≤623 K) for dehydriding. The kinetic equation is [-ln(1 - α)]3/2 = kt and the apparent activation energy for thenucleation and growth-controlled hydrogen absorption and desorption were determined to be 64.3±2.31 kJ/(mol.H2)and 59.9±2.99 kJ/(moI.H2) respectively.

  13. Experimental investigation of the catalytic decomposition and combustion characteristics of a non-toxic ammonium dinitramide (ADN)-based monopropellant thruster

    Science.gov (United States)

    Chen, Jun; Li, Guoxiu; Zhang, Tao; Wang, Meng; Yu, Yusong

    2016-12-01

    Low toxicity ammonium dinitramide (ADN)-based aerospace propulsion systems currently show promise with regard to applications such as controlling satellite attitude. In the present work, the decomposition and combustion processes of an ADN-based monopropellant thruster were systematically studied, using a thermally stable catalyst to promote the decomposition reaction. The performance of the ADN propulsion system was investigated using a ground test system under vacuum, and the physical properties of the ADN-based propellant were also examined. Using this system, the effects of the preheating temperature and feed pressure on the combustion characteristics and thruster performance during steady state operation were observed. The results indicate that the propellant and catalyst employed during this work, as well as the design and manufacture of the thruster, met performance requirements. Moreover, the 1 N ADN thruster generated a specific impulse of 223 s, demonstrating the efficacy of the new catalyst. The thruster operational parameters (specifically, the preheating temperature and feed pressure) were found to have a significant effect on the decomposition and combustion processes within the thruster, and the performance of the thruster was demonstrated to improve at higher feed pressures and elevated preheating temperatures. A lower temperature of 140 °C was determined to activate the catalytic decomposition and combustion processes more effectively compared with the results obtained using other conditions. The data obtained in this study should be beneficial to future systematic and in-depth investigations of the combustion mechanism and characteristics within an ADN thruster.

  14. Numerical Study on the Performance Characteristics of Hydrogen Fueled Port Injection Internal Combustion Engine

    Directory of Open Access Journals (Sweden)

    Rosli A. Bakar

    2009-01-01

    Full Text Available This study was focused on the engine performance of single cylinder hydrogen fueled port injection internal combustion engine. GT-Power was utilized to develop the model for port injection engine. One dimensional gas dynamics was represented the flow and heat transfer in the components of the engine model. The governing equations were introduced first, followed by the performance parameters and model description. Air-fuel ratio was varied from stoichiometric limit to a lean limit and the rotational speed varied from 2500 to 4500 rpm while the injector location was considered fixed in the midway of the intake port. The effects of air fuel ratio, crank angle and engine speed are presented in this study. From the acquired results show that the air-fuel ratio and engine speed were greatly influence on the performance of hydrogen fueled engine. It was shown that decreases the Brake Mean Effective Pressure (BMEP and brake thermal efficiency with increases of the engine speed and air-fuel ratio however the increase the Brake Specific Fuel Consumption (BSFC with increases the speed and air-fuel ratio. The cylinder temperature increases with increases of engine speed however temperature decreases with increases of air-fuel ratio. The pressure fluctuations increased substantially with increases of speed at intake port however rise of pressure at the end of the exhaust stroke lead to reverse flow into the cylinder past exhaust valve. The fluctuation amplitude responded to the engine speed in case of exhaust pressure were given less than the intake pressure. The volumetric efficiency increased with increases of engine speed and equivalent ratio. The volumetric efficiency of the hydrogen engines with port injection is a serious problem and reduces the overall performance of the engine. This emphasized the ability of retrofitting the traditional engines with hydrogen fuel with minor modifications.

  15. Turbulent combustion

    Energy Technology Data Exchange (ETDEWEB)

    Talbot, L.; Cheng, R.K. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    Turbulent combustion is the dominant process in heat and power generating systems. Its most significant aspect is to enhance the burning rate and volumetric power density. Turbulent mixing, however, also influences the chemical rates and has a direct effect on the formation of pollutants, flame ignition and extinction. Therefore, research and development of modern combustion systems for power generation, waste incineration and material synthesis must rely on a fundamental understanding of the physical effect of turbulence on combustion to develop theoretical models that can be used as design tools. The overall objective of this program is to investigate, primarily experimentally, the interaction and coupling between turbulence and combustion. These processes are complex and are characterized by scalar and velocity fluctuations with time and length scales spanning several orders of magnitude. They are also influenced by the so-called {open_quotes}field{close_quotes} effects associated with the characteristics of the flow and burner geometries. The authors` approach is to gain a fundamental understanding by investigating idealized laboratory flames. Laboratory flames are amenable to detailed interrogation by laser diagnostics and their flow geometries are chosen to simplify numerical modeling and simulations and to facilitate comparison between experiments and theory.

  16. 含碳偏二甲肼的点火和燃烧特性%Ignition and Combustion Characteristics of UDMH Containing Carbon

    Institute of Scientific and Technical Information of China (English)

    张蒙正; 郝智超; 张玫; 李军

    2012-01-01

    添加碳粉是提高推进剂能量密度的途径之一.为了获得含碳偏二甲肼UDMH的点火特性和高效燃烧室设计方法,设计了撞击式喷注器液体火箭发动机燃烧室,通过实验手段,研究了含碳UDMH的燃烧特性、燃烧室特征长度对燃烧效率的影响以及冷却特性.结果表明,含碳UDMH燃烧室的起动、关机和脉冲性能与液体推进剂相当;在UDMH中添加碳元素将导致推进剂密度比冲增加,燃烧效率降低;增加燃烧室特征长度有利于提高含碳UDMH的燃烧效率;含碳UDMH适应于液膜冷却.%Addition of C to liquid propellant is one of the methods for improving energy density. To obtain the ignition characteristic of UDMH containing carbon and the design method for high-efficiency combustion chamber, liquid rocket engine chamber is designed for the like-on-like injector. The combustion characteristic of UDMH containing carbon, the effect of characteristic chamber length on combustion efficiency and the cooling characteristic are experimentally studied. The results show that effective film cooling can be obtained using UDMH containing carbon are equivalent to those of liquid propellant. It is also shown that the addition of C to UDMH can result in the increase of density specific impulse and the decrease of combustion efficiency, and that with the increase of characteristic length, combustion efficiency increases.

  17. Real-time, adaptive machine learning for non-stationary, near chaotic gasoline engine combustion time series.

    Science.gov (United States)

    Vaughan, Adam; Bohac, Stanislav V

    2015-10-01

    Fuel efficient Homogeneous Charge Compression Ignition (HCCI) engine combustion timing predictions must contend with non-linear chemistry, non-linear physics, period doubling bifurcation(s), turbulent mixing, model parameters that can drift day-to-day, and air-fuel mixture state information that cannot typically be resolved on a cycle-to-cycle basis, especially during transients. In previous work, an abstract cycle-to-cycle mapping function coupled with ϵ-Support Vector Regression was shown to predict experimentally observed cycle-to-cycle combustion timing over a wide range of engine conditions, despite some of the aforementioned difficulties. The main limitation of the previous approach was that a partially acasual randomly sampled training dataset was used to train proof of concept offline predictions. The objective of this paper is to address this limitation by proposing a new online adaptive Extreme Learning Machine (ELM) extension named Weighted Ring-ELM. This extension enables fully causal combustion timing predictions at randomly chosen engine set points, and is shown to achieve results that are as good as or better than the previous offline method. The broader objective of this approach is to enable a new class of real-time model predictive control strategies for high variability HCCI and, ultimately, to bring HCCI's low engine-out NOx and reduced CO2 emissions to production engines.

  18. Influence of EGR compounds on the oxidation of an HCCI-diesel surrogate

    CERN Document Server

    Anderlohr, Jörg; Da Cruz, A Pires; Bounaceur, Roda; Battin-Leclerc, Frédérique; Dagaut, Philippe; Montagne, X; 10.1016/j.proci.2008.06.019

    2009-01-01

    This paper presents an experimental and numerical study of the impact of various additives on the oxidation of a typical automotive surrogate fuel blend, i.e. n-heptane and toluene. It examines the impact of engine re-cycled exhaust has compounds on the control of an Homogeneous Charge Compression-Ignition (HCCI) engine. Series of experiments were performed in a hihly diluted Jet-Stirred Reactor (JDR) at pressures of 1 and 10 atm (1 atm = 101,325 Pa). The chosen thermo-chemical conditions were close to those characteristices of the pre-ignition period in an HCCI engine. The influence of various additives, namely nitric oxide (NO), ethylene (C2H4) and methanol (CH3OH), on the oxidation of a n-heptane/toluene blend was studied over a wide range of temperatures (550-1100 K), including the zone of the Negative Temperature Coefficient (NTC).

  19. Influence of MnC2O4 microadditives on combustion characteristics of CuO/Al nanoenergetics

    Science.gov (United States)

    Painuly, Madhusudan; Patel, Vinay Kumar; Bhattacharya, Shantanu

    2016-05-01

    In this work, we have investigated the catalytic effect of MnC2O4 microrods on combustion characteristics of CuO/nAl nanoenergetic composites. CuO nanorods were prepared by solid state synthesis method using the nonionic surfactant of poly(ethylene)glycol of molecular weight 400 (PEG400). The crystal information and microstructure of CuO/nAl nanoenergetics were studied by X-ray diffractometry and Transmission Electron microscopy. Microrods shaped manganese oxalate (MnC2O4) were fabricated by using mild thermal precipitation and aging process and confirmed by energy dispersive X-ray spectroscopy (EDS). The microstructures of MnC2O4 microrods and the nanoenergetic composites of CuO/nAl/MnC2O4 were characterized by Field emission scanning electron microscopy (FE-SEM) imaging. The addition of MnC2O4 microrods has demonstrated a significant enhancement in dynamic pressure-time characteristics of CuO/nAl nanoenergetics.

  20. Investigation of emissions and combustion characteristics of a CI engine fueled with waste cooking oil methyl ester and diesel blends

    Directory of Open Access Journals (Sweden)

    K. Nantha Gopal

    2014-06-01

    Full Text Available Biodiesel has been identified as a potential alternative fuel for CI engines because use of biodiesel can reduce petroleum diesel consumption as well as engine out emissions. Out of many biodiesel derived from various resources, biodiesel from Waste Cooking Oil (WCO can be prepared economically using usual transesterification process. In the present study, in-depth research and comparative study of blends of biodiesel made from WCO and diesel is carried out to bring out the benefits of its extensive usage in CI engines. The experimental results of the study reveal that the WCO biodiesel has similar characteristics to that of diesel. The brake thermal efficiency, carbon monoxide, unburned hydrocarbon and smoke opacity are observed to be lower in the case of WCO biodiesel blends than diesel. On the other hand specific energy consumption and oxides of nitrogen of WCO biodiesel blends are found to be higher than diesel. In addition combustion characteristics of all biodiesel blends showed similar trends when compared to that of conventional diesel.

  1. Modeling of NO sensitization of IC engines surrogate fuels auto-ignition and combustion

    CERN Document Server

    Anderlohr, Jörg; Bounaceur, Roda; Battin-Leclerc, Frédérique

    2009-01-01

    This paper presents a new chemical kinetic model developed for the simulation of auto-ignition and combustion of engine surrogate fuel mixtures sensitized by the presence of NOx. The chemical mechanism is based on the PRF auto-ignition model (n-heptane/iso-octane) of Buda et al. [1] and the NO/n-butane/n-pentane model of Glaude et al. [2]. The later mechanism has been taken as a reference for the reactions of NOx with larger alcanes (n-heptane, iso-octane). A coherent two components engine fuel surrogate mechanism has been generated which accounts for the influence of NOx on auto-ignition. The mechanism has been validated for temperatures between 700 K and 1100 K and pressures between 1 and 10 atm covering the temperature and pressure ranges characteristic of engine post-oxidation thermodynamic conditions. Experiments used for validation include jet stirred reactor conditions for species evolution as a function of temperature, as well as diesel HCCI engine experiments for auto-ignition delay time measurements...

  2. Progressive combustion in SI-Engines—Experimental investigation on influence of combustion related parameters

    Indian Academy of Sciences (India)

    R Harish Kumar; A J Antony

    2008-12-01

    The fuel heat release rate which virtually controls the combustion process is dependent on the ‘Mass-Fraction-Burnt (MFB)’. In the present research work, a ‘logistic model with conditional variability in MFB’, has been developed for precise simulation of combustion in SI engines as the model has built in routines to take into account such factors as location of spark plug, single/dual spark plugs, intake generated swirl, combustion chamber geometry (associated with Bore/Stroke ratio), etc. A major contribution of this paper is that new and improved models for the ‘overall combustion duration’, and ‘ignition delay/flame development angle’, taking into account primarily the influence of compression ratio on the overall combustion process in SI engine have been developed. Taylor’s original equation for estimating the overall combustion duration has been modified by including a logistic equation for the error term and incorporating it in the original equation. Ignition delay as proposed by Keck et al has been modified by incorporating a polynomial of 3rd order into the original equation. The empirical correlations that have been proposed in this paper may serve to be the starting point for simulation of ‘photodetonation concept’ to simulate HCCI combustion which is presently the hot research work in the area of pre-mixed combustion. A program in Turbo-C++ has been developed for the complete simulation of SI engine combustion, taking into account the conditional variability effect, variable specific heats of burnt gases, dissociation of gases at high temperatures, progressive combustion phenomena, heat transfer (based on Woschni‘s equation), gas exchange process based on 1D-steady gas flow equation employing Taylor’s mach index of 0·6 for valve design.

  3. Trend and characteristics of atmospheric emissions of Hg, As, and Se from coal combustion in China, 1980–2007

    Directory of Open Access Journals (Sweden)

    H. Z. Tian

    2010-09-01

    Full Text Available Emissions of hazardous trace elements in China are of great concern because of their negative impacts on local air quality as well as on regional environmental health and ecosystem risks. In this paper, the atmospheric emissions of mercury (Hg, arsenic (As, and selenium (Se from coal combustion in China for the period 1980–2007 are estimated on the basis of coal consumption data and emission factors, which are specified by different categories of combustion facilities, coal types, and the equipped air pollution control devices configuration (Dust collectors, FGD, etc.. Specifically, multi-year emission inventories of Hg, As, and Se from 30 provinces and 4 economic sectors (thermal power, industry, residential use, and others are evaluated and analyzed in detail. Furthermore, the gridded distribution of provincial-based Hg, As, and Se emissions in 2005 at a resolution of 1°×1° is also plotted. It shows that the calculated national total atmospheric emissions of Hg, As, and Se from coal combustion have rapidly increased from 73.59 t, 635.57 t, and 639.69 t in 1980 to 305.95 t, 2205.50 t, and 2352.97 t in 2007, at an annually averaged growth rate of 5.4%, 4.7%, and 4.9%, respectively. The industrial sector is the largest source for Hg, As, and Se, accounting for about 50.8%, 61.2%, and 56.2% of the national totals, respectively. The share of power plants is 43.3% for mercury, 24.9% for arsenic, and 33.4% for selenium, respectively. Also, it shows remarkably different regional contribution characteristics of these 3 types of trace elements, the top 5 provinces with the heaviest mercury emissions in 2007 are Shandong (34.40 t, Henan (33.63 t, Shanxi (21.14 t, Guizhou (19.48 t, and Hebei (19.35 t; the top 5 provinces with the heaviest arsenic emissions in 2007 are Shandong (219.24 t, Hunan (213.20 t, Jilin (141.21 t, Hebei (138.54 t, and Inner Mongolia (127.49 t; while the top 5 provinces with the heaviest selenium emissions in 2007 are Shandong

  4. Trend and characteristics of atmospheric emissions of Hg, As, and Se from coal combustion in China, 1980-2007

    Science.gov (United States)

    Tian, H. Z.; Wang, Y.; Xue, Z. G.; Cheng, K.; Qu, Y. P.; Chai, F. H.; Hao, J. M.

    2010-12-01

    Emissions of hazardous trace elements in China are of great concern because of their negative impacts on local air quality as well as on regional environmental health and ecosystem risks. In this paper, the atmospheric emissions of mercury (Hg), arsenic (As), and selenium (Se) from coal combustion in China for the period 1980-2007 are estimated on the basis of coal consumption data and emission factors, which are specified by different categories of combustion facilities, coal types, and the equipped air pollution control devices configuration (Dust collectors, FGD, etc.). Specifically, multi-year emission inventories of Hg, As, and Se from 30 provinces and 4 economic sectors (thermal power, industry, residential use, and others) are evaluated and analyzed in detail. Furthermore, the gridded distribution of provincial-based Hg, As, and Se emissions in 2005 at a resolution of 1° × 1° is also plotted. It shows that the calculated national total atmospheric emissions of Hg, As, and Se from coal combustion have rapidly increased from 73.59 t, 635.57 t, and 639.69 t in 1980 to 305.95 t, 2205.50 t, and 2352.97 t in 2007, at an annually averaged growth rate of 5.4%, 4.7%, and 4.9%, respectively. The industrial sector is the largest source for Hg, As, and Se, accounting for about 50.8%, 61.2%, and 56.2% of the national totals, respectively. The share of power plants is 43.3% for mercury, 24.9% for arsenic, and 33.4% for selenium, respectively. Also, it shows remarkably different regional contribution characteristics of these 3 types of trace elements, the top 5 provinces with the heaviest mercury emissions in 2007 are Shandong (34.40 t), Henan (33.63 t), Shanxi (21.14 t), Guizhou (19.48 t), and Hebei (19.35 t); the top 5 provinces with the heaviest arsenic emissions in 2007 are Shandong (219.24 t), Hunan (213.20 t), Jilin (141.21 t), Hebei (138.54 t), and Inner Mongolia (127.49 t); while the top 5 provinces with the heaviest selenium emissions in 2007 are Shandong (289

  5. Fast Pyrolysis of Biomass in a Spout-fluidized Bed Reactor--Analysis of Composition and Combustion Characteristics of Liquid Product from Biomass

    Institute of Scientific and Technical Information of China (English)

    陈明强; 王君; 王新运; 张学才; 张素平; 任铮伟; 颜涌捷

    2006-01-01

    In order to gain insight into the fast pyrolysis mechanism of biomass and the relationship between bio-oil composition and pyrolysis reaction conditions, to assess the possibility for the raw bio-oil to be used as fuel, and to evaluate the concept of spout-fluidized bed reactor as the reactor for fast pyrolysis of biomass to prepare fuel oil, the composition and combustion characteristics of bio-oil prepared in a spout-fluidized bed reactor with a designed maximum capacity 5 kg/h of sawdust as feeding material, were investigated by GC-MS and thermogravimetry. 14 aromatic series chemicals were identified. The thermogravimetric analysis indicated that the bio-oil was liable to combustion, the combustion temperature increased with the heating rate, and only minute ash was generated when it burned. The kinetics of the combustion reaction was studied and the kinetic parameters were calculated by both Ozawa-Flynn-Wall and Popsecu methods. The results agree well with each other. The most probable combustion mechanism functions determined by Popescu method are f(α)=k(1-α)2(400~406 ℃), f(α)=1/2k(1-α)3 (406~416 ℃) and f( α)=2k(1-α)3/2 (416~430 ℃) respectively.

  6. Occurrence mode of chlorine in solid products from co-pyrolysis of coal and waste plastic and its emission characteristic during combustion

    Energy Technology Data Exchange (ETDEWEB)

    Li Zheng; Liu Ze-chang; Zhao Ying; Shi Yu-miao [Chemical and Environmental Engineering College of Shandong University of Science and Technology, Qingdao (China)

    2006-12-15

    The occurrence mode of chlorine in solid products from co-pyrolysis of coal and waste plastic was studied by IR and TG-MS. In addition, the emission characteristic of those solid products during combustion was studied. The results indicates that when co-pyrolysis temperature is below 600{sup o}C, there are some organic as well as inorganic chlorine compounds in coke; when the temperature is above 600{sup o}C, there is only inorganic one in the coke. The emission ratio of chlorine is relative to combustion temperature, the co-pyrolysing temperature as well as the percentage of PVC. The emission ratio of chlorine increases with the rising temperature of combustion. When the combustion temperature is 900{sup o}C, the emission ratio is up to 94%. On the contrary, the emission ratio is lower for the solid product from higher co-pyrolysis temperature as the combustion temperature is the same. The highest chlorine emission ratio from pyrolysis at 400{sup o}C is 99.86%, but that from 1000{sup o}C pyrolysis is 94.35%. 7 refs., 7 figs., 1 tab.

  7. COMBUSTION CHARACTERISTICS OF TORREFIED WOOD SAMPLES OF PINUS CARREBEA AND LEUCAENA LEUCOCEPHALA GROWN IN NIGERIA

    Directory of Open Access Journals (Sweden)

    Joseph Adeola FUWAPE

    2016-12-01

    Full Text Available Torrefaction of selected wood samples of Pinus Carrebea and Leucaena Leucocephala were carried out at temperatures ranging from 200 to 300°C to improve the energy parameters of biomass and to determine the effect of torrefication temperature on the physical and combustion properties of wood selected from Pinus carrebea and Leuceanea leucocephala grown in Nigeria. In this process the biomass hemicellulose is degraded, maintaining its cellulose and lignin content. The samples were dried and heated to 225, 250, 275, and 300°C. Then the torrefied mass was subjected to basic property testing on proximate analysis and heating value was calculated in order to understand the differences between raw material and its torrefied products. Specifically, the wood blocks changed from light brown to black, stemming from the partial carbonization at the wood surface. When the temperature is 225°C, the color of the wood is between dark brown and once the torrefaction temperatures are 250 and 275°C, the colors of the wood become dark and darker respectively. The results of the proximate analysis also showed that increasing of torrefied temperature; volatile fraction was reduced while fixed carbon was increased with increase in temperature from 21.34 to 52.74 and 18.58 to 56.83 for Leucaena leucocephala and Pinus carreabeanus respectively at 225 to 300°C. The volatile content is decreased from 78.58% to 62.76% with increase in temperature. Ash content of were within 1.57-3.41% of torrefied wood. It could be observed that the High calorific value (HCV for pine ranged between 19.80 and 28.06MJ/Kg for the top, 19.93and 24.96MJ/kg for middle with 19.72and 25.96MJ/Kg for base. The values recorded for raw sample and at 275°C been the lowest and highest respectively. The High calorific value (HCV were found to be on the increase and nose dive at 300°C for the tree parts used in this research. The result revealed that for Leuceana the value increased from raw up to

  8. Laser-assisted homogeneous charge ignition in a constant volume combustion chamber

    Science.gov (United States)

    Srivastava, Dhananjay Kumar; Weinrotter, Martin; Kofler, Henrich; Agarwal, Avinash Kumar; Wintner, Ernst

    2009-06-01

    Homogeneous charge compression ignition (HCCI) is a very promising future combustion concept for internal combustion engines. There are several technical difficulties associated with this concept, and precisely controlling the start of auto-ignition is the most prominent of them. In this paper, a novel concept to control the start of auto-ignition is presented. The concept is based on the fact that most HCCI engines are operated with high exhaust gas recirculation (EGR) rates in order to slow-down the fast combustion processes. Recirculated exhaust gas contains combustion products including moisture, which has a relative peak of the absorption coefficient around 3 μm. These water molecules absorb the incident erbium laser radiations ( λ=2.79 μm) and get heated up to expedite ignition. In the present experimental work, auto-ignition conditions are locally attained in an experimental constant volume combustion chamber under simulated EGR conditions. Taking advantage of this feature, the time when the mixture is thought to "auto-ignite" could be adjusted/controlled by the laser pulse width optimisation, followed by its resonant absorption by water molecules present in recirculated exhaust gas.

  9. Impact of the Flame-Holder Heat-Transfer Characteristics on the Onset of Combustion Instability

    KAUST Repository

    Hong, Seunghyuck

    2013-10-03

    In this article, we investigate the impact of heat transfer between the flame and the flameholder on the dynamic stability characteristics of a 50-kW backward-facing step combustor. We conducted a series of tests where two backward step blocks were used, made of ceramic and stainless steel, whose thermal conductivities are 1.06 and 12 W/m/K, respectively. Stability characteristics of the two flame-holder materials were examined using measurements of the dynamic pressure and flame chemiluminescence over a range of operating conditions. Results show that with the ceramic flameholder, the onset of instability is significantly delayed in time and, for certain operating conditions, disappears altogether, whereas with the higher conductivity material, the combustor becomes increasingly unstable over a range of operating conditions. We explain these trends using the heat flux through the flameholder and the change in the burning velocity near the step wall. Results suggest a potential approach using low-thermal-conductivity material near the flame-holder as passive dynamics suppression methods. Copyright © Taylor & Francis Group, LLC.

  10. The effects of hydrous ethanol gasoline on combustion and emission characteristics of a port injection gasoline engine

    Directory of Open Access Journals (Sweden)

    Xiaochen Wang

    2015-09-01

    Full Text Available Comparative experiments were conducted on a port injection gasoline engine fueled with hydrous ethanol gasoline (E10W, ethanol gasoline (E10 and pure gasoline (E0. The effects of the engine loads and the additions of ethanol and water on combustion and emission characteristics were analyzed deeply. According to the experimental results, compared with E0, E10W showed higher peak in-cylinder pressure at high load. Increases in peak heat release rates were observed for E10W fuel at all the operating conditions. The usage of E10W increased NOX emissions at a wide load range. However, at low load conditions, E10W reduced HC, CO and CO2 emissions significantly. E10W also produced slightly less HC and CO emissions, while CO2 emissions were not significantly affected at higher operating points. Compared with E10, E10W showed higher peak in-cylinder pressures and peak heat release rates at the tested operating conditions. In addition, decreases in NOX emissions were observed for E10W from 5 Nm to 100 Nm, while HC, CO and CO2 emissions were slightly higher at low and medium load conditions. From the results, it can be concluded that E10W fuel can be regarded as a potential alternative fuel for gasoline engine applications.

  11. Influence of Coal nature and Structure on Ash Size Formation Characteristic and Related pollutant Emissions During CFB Combustion

    Institute of Scientific and Technical Information of China (English)

    MinQIAN; YongjieNA; 等

    2000-01-01

    The size distribution of coal particles in a Circulating Fluidized Bed(CFB) boiler plays a crucial role in the complicated combustion,heat exchange and pollutant emissions in such a plant.Therefore,it is fundamental to study the different factors having influence on the size distribution of coal particles.Above all,the coal itself and in particular,the coal comminution phenomenon is a very influent factor.In the frame of this work,the coal nature (eleentary compostion) and coal internal structure (mineral componeents) are studied in detail.At this intermediary stage,experients on three typical Chinese coals on a 1.5 MWt CFBC pilot plant have been made.Some primary fragmentation test hae also been made in a small lab scale fluidized bed reactor.The resutls from the hot pilot test show i)the variation of coal ash distributions and other CFB performance data due to the cyclone and the coal characteristics and ii) the variation of desulfurization efficiency with limestone.Whereas the bench scale primary fragmentation test,likely linked to the caking propriety of a coal,does not seem to change considerable the char size distribution.

  12. Characteristics of ammonia emission during thermal drying of lime sludge for co-combustion in cement kilns.

    Science.gov (United States)

    Liu, Wei; Xu, Jingcheng; Liu, Jia; Cao, Haihua; Huang, Xiang-Feng; Li, Guangming

    2015-01-01

    Thermal drying was used to reduce sludge moisture content before co-combustion in cement kilns. The characteristics of ammonia (NH3) emission during thermal drying of lime sludge (LS) were investigated in a laboratory-scale tubular dry furnace under different temperature and time conditions. As the temperature increased, the NH3 concentration increased in the temperature range 100-130°C, decreased in the temperature range 130-220°C and increased rapidly at >220°C. Emission of NH3 also increased as the lime dosage increased and stabilized at lime dosages>5%. In the first 60 min of drying experiments, 55% of the NH3 was released. NH3 accounted for about 67-72% of the change in total nitrogen caused by the release of nitrogen-containing volatile compounds (VCs) from the sludge. X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy revealed that the main forms of nitrogen in sludge were amides and amines. The addition of lime (CaO) could cause conversion of N-H, N-O or C-N containing compounds to NH3 during the drying process.

  13. Comparative Study of Performance and Combustion Characteristics of Conventional and Low Heat Rejection (Mullite Coated) Diesel Engines

    Science.gov (United States)

    Patond, S. B.; Chaple, S. A.; Shrirao, P. N.; Shaikh, P. I.

    2013-06-01

    Tests were performed on a single cylinder, four stroke, direct injection, diesel engine whose piston crown, cylinder head and valves were coated with a 0.5 mm thickness of 3Al2O3·2SiO2 (mullite) (Al2O3 = 60%, SiO2 = 40%) over a 150 μm thickness of NiCrAlY bond coat. The working conditions for the conventional engine (without coating) and LHR (mullite coated) engine were kept exactly same to ensure a comparison between the two configurations of the engine. This paper is intended to emphasis on performance and combustion characteristics of conventional and LHR (Mullite coated) diesel engines under identical conditions. Tests were carried out at same operational constraints i.e. air-fuel ratio and engine speed conditions for both conventional engine (without coating) and LHR (mullite coated) engines. The results showed that, there was as much as 1.8 % increasing on brake power for LHR (mullite coated) engine compared to conventional engine (without coating) at full load The average decrease in brake specific fuel consumption in the LHR engine compared with the conventional engine was 1.76 % for full engine load. However, there was increasing on cylinder gas pressure and net heat release rate for LHR engine compared to conventional engine. Also the results revealed that, there was as much as 22% increasing on exhaust gas temperature for LHR engine compared to conventional engine at full engine load.

  14. Structural, electrical and magnetic characteristics of nickel substituted cobalt ferrite nano particles, synthesized by self combustion method

    Energy Technology Data Exchange (ETDEWEB)

    Sontu, Uday Bhasker, E-mail: sontuudaybhasker@yahoo.co.in; Yelasani, Vijayakumar; Musugu, Venkata Ramana Reddy

    2015-01-15

    Nickel-substituted cobalt ferrite nano-particles are synthesized using a self-combustion method. Aqueous metal nitrates and citric acid form the precursors. No external oxidizing agents are used to change the pH of the precursors; this resulted in a more environment friendly synthesis. Structural, magnetic and electrical characteristics of the nano ferrites are verified using X-ray diffractometer (XRD), VSM and impedance analyzer respectively. Phase formation, particle size, lattice parameter, X-ray density, saturation magnetization, coercivity, dielectric constant and electrical activation energy as function of nickel substitution in cobalt ferrite are studied. It is shown here that the magnetic and electrical properties can be tuned by varying the nickel concentration. - Highlights: • Environmentally less polluting and simple, industrially scalable method of nano-ferrite synthesis. • Repeatability of the method is self-evident from consistent particle size. • Electrical and magnetic properties are tunable due to nickel substitution. • Nickel substitution increases dielectric constant value and also improves electrical resistivity. • Higher concentration of Ni introduces phase impurity into the cubic spinel ferrite.

  15. Experimental study on the effects of the number of heat exchanger modules on thermal characteristics in a premixed combustion system

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Byeonghun; Lee, Chang-Eon [Inha University, Incheon (Korea, Republic of); Kum, Sung Min [Halla University, Wonju (Korea, Republic of); Lee, Seungro [Chonbuk National University, Jeonju (Korea, Republic of)

    2016-01-15

    The effects of the number of heat exchanger modules on thermal characteristics were experimentally studied in a premixed combustion system with a cross-flow staggered-tube heat exchanger. The various heat exchanger modules, from 4 to 8, combined with a premixed burner were tested to investigate the performance of the heat exchanger through the surface area of the heat exchanger at various equivalence ratios. Additionally, the performance of the heat exchanger was analyzed by applying entropy generation theory to the heat exchanger system. As a result, although the heat transfer rate increases with the increase of the equivalence ratio, the NOx and CO concentrations also increase due to the increasing flame temperature. In addition, the entropy generation increases with an increase of the equivalence ratio. Furthermore, the heat transfer rate and the effectiveness are increased with the increase of the number of the heat exchanger modules. Also, the effectiveness is sharply increased when the number of the heat exchanger modules is increased from 4 to 5. Consequently, the optimal operating conditions regarding pollutant emission, effectiveness and entropy generation in this experimental range are 0.85 for the equivalence ratio and 8 for the number of heat exchanger modules.

  16. EFFECTS OF ETHANOL-DIESEL EMULSIONS ON THE PERFORMANCE, COMBUSTION AND EMISSION CHARACTERISTICS OF DI DIESEL ENGINE

    Directory of Open Access Journals (Sweden)

    R. Parthasarathi

    2014-01-01

    Full Text Available The main objective of this study is to analyze the different ratio of emulsified fuels on the performance, emission and combustion characteristics of four stroke single cylinder kirloskar TV-I direct injection compression ignition engine and compared with diesel fuel under different engine loads with constant engine speed of 1500 rpm. Four kinds of test fuels were prepared namely 80% diesel, 10% ethanol and 10% surfactant (Identified as D80E10; 70% diesel, 20% ethanol and 10% surfactant (denoted as D70 E20; 60% diesel 30% ethanol and 10% surfactant (denoted as D60 E30; 50% diesel, 40% ethanol and 10% surfactant (denoted as D50 E40 by volume respectively. In this test, Benzal konium chloride is added as an emulsifier to the diesel-ethanol blend to prevent layer formation and to make it a homogeneous blend. At maximum brake power, the comparison of best emulsified fuel ratio with diesel fuel results showed improvement in brake thermal efficiency with decrease in specific fuel consumption and smoke. The NOX, HC, CO2, cylinder pressure and heat release rate for D50 E40 emulsions are higher when compared to diesel fuel.

  17. Analysis of the Effect of the Swirl Flow Intensity on Combustion Characteristics in Liquid Fuel Powered Confined Swirling Flames

    Directory of Open Access Journals (Sweden)

    Marko Klancisar

    2016-01-01

    Full Text Available This article examines the implementation of CFD technology in the design of the industrial liquid fuel powered swirl flame burner. The coupling between the flow field and the combustion model is based on the eddy dissipation model. The choice of the LES (Large Eddy Simulation turbulence model over standard RANS (Reynolds Averaged Navier-Stokes offers a possibility to improve the quality of the combustion-flow field interaction. The Wall Adapting Local Eddy-Viscosity (WALE sub-grid model was used. The reaction chemistry is a simple infinitely fast one step global irreversible reaction. The computational model was setup with the Ansys-CFX software. Through the detailed measurements of industrial size burner, it was possible to determine the natural operational state of the burner according to the type of fuel used. For the inlet conditions, axial and radial velocity components were calculated from known physical characteristics of both the fuel and air input, with the initial tangential velocity of the fuel assumed as18% of the initial axial fuel velocity. Different swirl number (S values were studied. Addition of a surplus (in comparison to conventional flame stabilization of tangential air velocity component (W, the rotational component increases itself with a considerably high magnitude, contributing to the overall flame stabilization. The level of S especially influences the turbulent energy, its dissipation rate and turbulent (Reynolds stresses. In the case of high swirl number values (S > 0,65 it is possible to divide the flow field in three principle areas: mixing area (fuel-air, where exothermal reactions are taking place, central recirculation area and outer recirculation area, which primarily contains the flow of burnt flue gases. The described model was used to determine the flow and chemical behavior, whereas the liquid atomization was accounted for by LISA (Linear Instability Sheet Atomization model incorporating also the cavitation

  18. Improving the performance and emission characteristics of a single cylinder diesel engine having reentrant combustion chamber using diesel and Jatropha methyl esters.

    Science.gov (United States)

    Premnath, S; Devaradjane, G

    2015-11-01

    The emissions from the Compression ignition (CI) engines introduce toxicity to the atmosphere. The undesirable carbon deposits from these engines are realized in the nearby static or dynamic systems such as vehicles, inhabitants, etc. The objective of this research work is to improve the performance and emission characteristics of a diesel engine in the modified re-entrant combustion chamber using a diesel and Jatropha methyl ester blend (J20) at three different injection pressures. From the literature, it is revealed that the shape of the combustion chamber and the fuel injection pressure have an impact on the performance and emission parameters of the CI engine. In this work, a re-entrant combustion chamber with three different fuel injection pressures (200, 220 and 240bars) has been used in the place of the conventional hemispherical combustion chamber for diesel and J20. From the experimental results, it is found that the re-entrant chamber improves the brake thermal efficiency of diesel and J20 in all the tested conditions. It is also found that the 20% blend of Jatropha methyl ester showed 4% improvement in the brake thermal efficiency in the re-entrant chamber at the maximum injection pressure. Environmental safety directly relates to the reduction in the undesirable effects on both living and non-living things. Currently environmental pollution is of major concern. Even with the stringent emission norms new methods are required to reduce the harmful effects from automobiles. The toxicity of carbon monoxide (CO) is well known. In the re-entrant combustion chamber, the amount of CO emission is reduced by 26% when compared with the conventional fuel operation of the engine. Moreover, the amount of smoke is reduced by 24% and hydrocarbons (HC) emission by 24%. Thus, the modified re-entrant combustion chamber reduces harmful pollutants such as unburned HC and CO as well as toxic smoke emissions.

  19. Numerical and Experimental Study on the Combustion and Emission Characteristics of a Dimethyl Ether (DME Fueled Compression Ignition Engine Études numériques et expérimentales sur les caractéristiques de combustion et d’émissions d’un éther diméthylique (EDM- moteur à auto-allumage rempli de combustible

    Directory of Open Access Journals (Sweden)

    Kim Hyung Jun

    2012-05-01

    Full Text Available A numerical investigation was carried out to study on the combustion and emission characteristics of dimethyl ether (DME with wide ranges of injection timings in compression ignition engines. In order to simulate DME combustion processes, a KIVA-3V code coupled with a chemistry solver was used to solve the detailed chemical kinetics model of DME oxidation. In addition, the Kelvin-Helmholtz-Rayleigh-Taylor (KH-RT hybrid breakup model and Renormalization Group (RNG k-ε  models were applied to analyze the spray characteristics and turbulent flow, respectively. To predict the NOx formation during DME combustion, a reduced Gas Research Institute (GRI NO mechanism was used. From these results on the combustion and emission, the calculated results were compared with experimental ones for the same operating conditions. In the combustion characteristics, the calculated combustion pressure and heat release rates agreed well with experimental results. The levels of experimental NOx emissions was reduced as the start of the injection timing retarded, and also these trends appeared in calculated emission characteristics. Additionally, the calculated CO and HC emissions show an increasing trend as the start of the injection is retarded. Dans cette étude, nous considérons la simulation de la combustion du dimethyl ether (DME dans un moteur à allumage par compression. Les caractéristiques de la combustion ainsi que les émissions polluantes sont analysées sur une large gamme d’avance à l’injection. Afin de simuler le processus de combustion du EDM, le code KIVA-3V couplé à un solveur chimique a été utilisé pour résoudre la cinétique détaillée de l’oxydation du EDM. Le modèle de rupture de Kelvin-Helmholtz-Rayleigh- Taylor (KH-RT ainsi que le modèle de turbulence k-ε  RNG ont été appliqués pour analyser respectivement les caractéristiques du jet et l’écoulement turbulent. Pour prévoir la formation de NOx pendant la combustion

  20. Conditions and Characteristics of the Ignition of a Typical Vegetable Combustible Material by a Local Energy Source

    Science.gov (United States)

    Baranovskii, N. V.; Zakharevich, A. V.

    2016-11-01

    This paper presents the results of experimental studies of the ignition of a typical vegetable combustible material (dry grass) by a single particle heated to high temperatures. The ignition conditions correspond to the rather typical conditions of the action on a vegetable combustible. The dependence of the ignition delay time of dry grass on the initial temperature of the particle has been obtained, and the limiting temperatures of combustion initiation have been determined. A hypothesis on the mechanism of heat transfer in a heated bed of the material during the induction period has been formulated.

  1. Sensitivity of combustion and ignition characteristics of the solid-fuel charge of the microelectromechanical system of a microthruster to macrokinetic and design parameters

    Science.gov (United States)

    Futko, S. I.; Ermolaeva, E. M.; Dobrego, K. V.; Bondarenko, V. P.; Dolgii, L. N.

    2012-07-01

    We have developed a sensitivity analysis permitting effective estimation of the change in the impulse responses of a microthrusters and in the ignition characteristics of the solid-fuel charge caused by the variation of the basic macrokinetic parameters of the mixed fuel and the design parameters of the microthruster's combustion chamber. On the basis of the proposed sensitivity analysis, we have estimated the spread of both the propulsive force and impulse and the induction period and self-ignition temperature depending on the macrokinetic parameters of combustion (pre-exponential factor, activation energy, density, and heat content) of the solid-fuel charge of the microthruster. The obtained results can be used for rapid and effective estimation of the spread of goal functions to provide stable physicochemical characteristics and impulse responses of solid-fuel mixtures in making and using microthrusters.

  2. Characteristics of natural gas lean combustion through the compression of quiescent charge in a rapid compression combustor; Kyusoku asshuku nensho sochinai seishi yokongoki asshuku ni okeru tennen gas no kihaku nensho tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Kataoka, K. [Okayama University of Science, Okayama (Japan); Segawa, D.; Kadota, T.; Hirooka, S. [University of Osaka Prefecture, Osaka (Japan). Faculty of Engineering; Higashino, K. [Osaka Gas Co. Ltd., Osaka (Japan)

    1997-04-25

    In order to develop a natural gas fueled spark ignition engine with high thermal efficiency and clean exhaust gases, combustion characteristics of natural gas and air mixtures were examined using a rapid compression combustor. We concentrated on lean mixtures because of their potential for high efficiency and low pollutant emissions. To elucidate the effect of compression-induced physical aspects on the combustion process, the charge was kept quiescent before the start of the compression process. The results showed that an increased charge pressure increased the time required for combustion. A high compression ratio or piston speed tended to shorten the combustion time, but their effects were rather weak. An increased humidity in mixtures measurably increased the combustion time. The stratified charge, which was examined using the soap bubble method, markedly improved the combustion process of lean mixtures. 7 refs., 15 figs., 1 tab.

  3. Properties of chicken manure pyrolysis bio-oil blended with diesel and its combustion characteristics in RCEM, Rapid Compression and Expansion Machine

    Directory of Open Access Journals (Sweden)

    Sunbong Lee

    2014-06-01

    Full Text Available Bio-oil (bio-oil was produced from chicken manure in a pilot-scale pyrolysis facility. The raw bio-oil had a very high viscosity and sediments which made direct application to diesel engines difficult. The bio-oil was blended with diesel fuel with 25% and 75% volumetric ratio at the normal temperature, named as blend 25. A rapid compression and expansion machine was used for a combustion test under the experimental condition corresponding to the medium operation point of a light duty diesel engine using diesel fuel, and blend 25 for comparison. The injection related pressure signal and cylinder pressure signal were instantaneously picked up to analyze the combustion characteristics in addition to the measurement of NOx and smoke emissions. Blend 25 resulted in reduction of the smoke emission by 80% and improvements of the apparent combustion efficiency while the NOx emission increased by 40%. A discussion was done based on the analysis results of combustion.

  4. Effect of fuel-to-nitrate ratio on the powder characteristics of nanosized CeO{sub 2} synthesized by mixed fuel combustion method

    Energy Technology Data Exchange (ETDEWEB)

    Palneedi, Haribabu; Mangam, Venu; Das, Siddhartha [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur 721302 (India); Das, Karabi, E-mail: karabi@metal.iitkgp.ernet.in [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur 721302 (India)

    2011-10-13

    Highlights: > Preparation of nanosized ceria powder by mixed fuel combustion synthesis. > Effect of variation of fuel-to-nitrate ratio on the powder characteristics. > Correlation between the results of XRD, Raman spectroscopy, and BET surface analysis. - Abstract: Synthesis of nanocrystalline ceria powders is carried out through the mixed fuel combustion approach by using different combinations of glycine and citric acid. The powders obtained with different fuel-to-nitrate (F/N) ratios are characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), BET surface area analysis, and Raman spectroscopy. TGA and FTIR spectroscopy studies have revealed the presence of carbonaceous species and residual volatiles in the combustion synthesized ceria powders. It is observed that the variation of fuel-to-nitrate ratio has a profound influence on the carbonaceous residues from combustion, crystallite size (11-44 nm), surface area (9-39 m{sup 2}/g) and morphology of the resultant powders. The Raman spectroscopy results on the variation of particle size with F/N ratio are consistent with the conclusions made from X-ray line broadening and BET surface area analysis.

  5. Comparing Spray Characteristics from Reynolds Averaged Navier-Stokes (RANS) National Combustion Code (NCC) Calculations Against Experimental Data for a Turbulent Reacting Flow

    Science.gov (United States)

    Iannetti, Anthony C.; Moder, Jeffery P.

    2010-01-01

    Developing physics-based tools to aid in reducing harmful combustion emissions, like Nitrogen Oxides (NOx), Carbon Monoxide (CO), Unburnt Hydrocarbons (UHC s), and Sulfur Dioxides (SOx), is an important goal of aeronautics research at NASA. As part of that effort, NASA Glenn Research Center is performing a detailed assessment and validation of an in-house combustion CFD code known as the National Combustion Code (NCC) for turbulent reacting flows. To assess the current capabilities of NCC for simulating turbulent reacting flows with liquid jet fuel injection, a set of Single Swirler Lean Direct Injection (LDI) experiments performed at the University of Cincinnati was chosen as an initial validation data set. This Jet-A/air combustion experiment operates at a lean equivalence ratio of 0.75 at atmospheric pressure and has a 4 percent static pressure drop across the swirler. Detailed comparisons of NCC predictions for gas temperature and gaseous emissions (CO and NOx) against this experiment are considered in a previous work. The current paper is focused on detailed comparisons of the spray characteristics (radial profiles of drop size distribution and at several radial rakes) from NCC simulations against the experimental data. Comparisons against experimental data show that the use of the correlation for primary spray break-up implemented by Raju in the NCC produces most realistic results, but this result needs to be improved. Given the single or ten step chemical kinetics models, use of a spray size correlation gives similar, acceptable results

  6. Combustion characteristics of paper mill sludge in a lab-scale combustor with internally cycloned circulating fluidized bed.

    Science.gov (United States)

    Shin, D; Jang, S; Hwang, J

    2005-01-01

    After performing a series of batch type experiments using a lab-scale combustor, consideration was given to the use of an internally cycloned circulating fluidized bed combustor (ICCFBC) for a paper mill sludge. Operation parameters including water content, feeding mass of the sludge, and secondary air injection ratio were varied to understand their effects on combustion performance, which was examined in terms of carbon conversion rate (CCR) and the emission rates of CO, C(x)H(y) and NO(x). The combustion of paper mill sludge in the ICCFBC was compared to the reaction mechanisms of a conventional solid fuel combustion, characterized by kinetics limited reaction zone, diffusion limited reaction zone, and transition zone. The results of the parametric study showed that a 35% water content and 60 g feeding mass generated the best condition for combustion. Meanwhile, areal mass burning rate, which is an important design and operation parameter at an industrial scale plant, was estimated by a conceptual equation. The areal mass burning rate corresponding to the best combustion condition was approximately 400 kg/hm(2) for 35% water content. The secondary air injection generating swirling flow enhanced the mixing between the gas phase components as well as the solid phase components, and improved the combustion efficiency by increasing the carbon conversion rate and reducing pollutant emissions.

  7. The Effect of Hydrogen Addition on the Combustion Characteristics of RP-3 Kerosene/Air Premixed Flames

    Directory of Open Access Journals (Sweden)

    Wen Zeng

    2017-07-01

    Full Text Available Experimental studies have been performed to investigate the effects of hydrogen addition on the combustion characteristics of Chinese No.3 jet fuel (RP-3 kerosene/air premixed flames. Experiments were carried out in a constant volume chamber and the influences of the initial temperatures of 390 and 420 K, initial pressures of 0.1 and 0.3 MPa, equivalence ratios of 0.6–1.6 and hydrogen additions of 0.0–0.5 on the laminar burning velocities, and Markstein numbers of Hydrogen (H2/RP-3/air mixtures were investigated. The results show that the flame front surfaces of RP-3/air mixtures remain smooth throughout the entire flame propagation process at a temperature of 390 K, pressure of 0.3 MPa, equivalence ratio of 1.3 and without hydrogen addition, but when the hydrogen addition increases from 0.0 to 0.5 under the same conditions, flaws and protuberances occur at the flame surfaces. It was also found that with the increase of the equivalence ratio from 0.9 to 1.5, the laminar burning velocities of the mixtures increase at first and then decrease, and the highest laminar burning velocity was measured at an equivalence ratio of 1.2. Meanwhile, with the increase of hydrogen addition, laminar burning velocities of H2/RP-3/air mixtures increase. However, the Markstein numbers of H2/RP-3/air mixtures decrease with the increase of hydrogen addition, which means that the flames of H2/RP-3/air mixtures become unstable with the increase of hydrogen addition.

  8. Internal combustion engine report: Spark ignited ICE GenSet optimization and novel concept development

    Energy Technology Data Exchange (ETDEWEB)

    Keller, J.; Blarigan, P. Van [Sandia National Labs., Livermore, CA (United States)

    1998-08-01

    In this manuscript the authors report on two projects each of which the goal is to produce cost effective hydrogen utilization technologies. These projects are: (1) the development of an electrical generation system using a conventional four-stroke spark-ignited internal combustion engine generator combination (SI-GenSet) optimized for maximum efficiency and minimum emissions, and (2) the development of a novel internal combustion engine concept. The SI-GenSet will be optimized to run on either hydrogen or hydrogen-blends. The novel concept seeks to develop an engine that optimizes the Otto cycle in a free piston configuration while minimizing all emissions. To this end the authors are developing a rapid combustion homogeneous charge compression ignition (HCCI) engine using a linear alternator for both power take-off and engine control. Targeted applications include stationary electrical power generation, stationary shaft power generation, hybrid vehicles, and nearly any other application now being accomplished with internal combustion engines.

  9. The effects of ethanol addition with waste pork lard methyl ester on performance, emission and combustion characteristics of a diesel engine

    Directory of Open Access Journals (Sweden)

    John Panneer Selvam Dharmaraj

    2014-01-01

    Full Text Available In the recent research, as a result of depletion of world petroleum reserves, considerable attention has been focused on the use of different alternative fuels in diesel engines. The present work aims to ensure the possibility of adding ethanol as an additive with animal fat biodiesel that is tested as an alternative fuel for diesel in a CI engine. In this study, biodiesel is obtained from waste pork lard by base-catalyzed transesterification with methanol when potassium hydroxide as catalyst. 2.5%, 5% and 7.5% by volume of ethanol is blended with neat biodiesel in order to improve performance and combustion characteristics of a diesel engine. The experimental work is carried out in a 3.7 kW, single cylinder, naturally aspirated, water cooled, direct injection diesel engine for different loads and at a constant speed of 1500 rpm. The performance, emission and combustion characteristics of biodiesel-ethanol blends are investigated by comparing them with neat biodiesel and standard diesel. The experimental test results showed that the combustion and performance characteristics improved with the increase in percentage of ethanol addition with biodiesel. When compared to neat biodiesel and standard diesel, an increase in brake thermal efficiency of 5.8% and 4.1% is obtained for BEB7.5 blend at full load of the engine. With the increase in percentage of ethanol fraction in the blends, peak cylinder pressure and the corresponding heat release rate are increased. Biodiesel-ethanol blends exhibit longer ignition delay and shorter combustion duration when compared to neat biodiesel. Optimum reduction in carbon monoxide, unburned hydrocarbon and smoke emission are attained while using BEB5 blend at full load of the engine. However, there is an adverse effect in case of nitrogen oxide emission.

  10. Performance, emission and combustion characteristics of a semi-adiabatic diesel engine using cotton seed and neem kernel oil methyl esters

    Directory of Open Access Journals (Sweden)

    Basavaraj M. Shrigiri

    2016-03-01

    Full Text Available The performance, emission and combustion characteristics of a diesel engine are investigated using two methyl esters: One obtained from cotton seed oil and other from neem kernel oil. These two oils are transesterified using methanol and alkaline catalyst to produce the cotton seed oil methyl ester (CSOME and neem kernel oil methyl ester (NKOME respectively. These biodiesels are used as alternative fuels in low heat rejection engine (LHR, in which the combustion chamber temperature is increased by thermal barrier coating on piston face. Experimental investigations are conducted with CSOME and NKOME in a single cylinder, four stroke, direct injection LHR engine. It is found that, at peak load the brake thermal efficiency is lower by 5.91% and 7.07% and BSFC is higher by 28.57% and 10.71% for CSOME and NKOME in LHR engine, respectively when compared with conventional diesel fuel used in normal engine. It is also seen that there is an increase in NOx emission in LHR engine along with slight increase in CO, smoke and HC emissions. From the combustion characteristics, it is found that the values of cylinder pressure for CSOME and NKOME in LHR engine are near to the diesel fuel in normal engine.

  11. Numerical Analysis of the Combustion and Emission Characteristics of Diesel Engines with Multiple Injection Strategies Using a Modified 2-D Flamelet Model

    Directory of Open Access Journals (Sweden)

    Gyujin Kim

    2017-08-01

    Full Text Available The multiple injection strategy has been widely used in diesel engines to reduce engine noise, NOx and soot formation. Fuel injection developments such as the common-rail and piezo-actuator system provide more precise control of the injection quantity and time under higher injection pressures. As various injection strategies become accessible, it is important to understand the interaction of each fuel stream and following combustion process under the multiple injection strategy. To investigate these complex processes quantitatively, numerical analysis using CFD is a good alternative to overcome the limitation of experiments. A modified 2-D flamelet model is further developed from previous work to model multi-fuel streams with higher accuracy. The model was validated under various engine operating conditions and captures the combustion and emissions characteristics as well as several parametric variations. The model is expected to be used to suggest advanced injection strategies in engine development processes.

  12. Numerical Analysis of Autoignition and Combustion of n-Butane and Air Mixture in Homogeneous-Charge Compression-Ignition Engine Using Elementary Reactions

    Science.gov (United States)

    Yamasaki, Yudai; Iida, Norimasa

    The present study focuses on clarifying the combustion mechanism of the homogeneous-charge compression-ignition (HCCI) engine in order to control ignition and combustion as well as to reduce HC and CO emissions and to maintain high combustion efficiency by calculating the chemical kinetics of elementary reactions. For the calculations, n-butane was selected as fuel since it is a fuel with the smallest carbon number in the alkane family that shows two-stage autoignition (heat release with low-temperature reaction (LTR) and with high-temperature reaction (HTR)) similarly to higher hydrocarbons such as gasoline. The CHEMKIN code was used for the calculations assuming zero dimensions in the combustion chamber and adiabatic change. The results reveal the heat release mechanism of the LTR and HTR, the control factor of ignition timing and combustion speed, and the condition need to reduce HC and CO emissions and to maintain high combustion efficiency.

  13. Optical Engines as Representative Tools in the Development of New Combustion Engine Concepts Moteurs transparents comme outils représentatifs dans le développement de nouveaux concepts des moteurs à combustion interne

    Directory of Open Access Journals (Sweden)

    Kashdan J.

    2011-11-01

    (EGR. A comparison has been made between simulated EGR (using pure nitrogen with real EGR under Diesel LTC conditions. Finally, “pure”, single component fuels are often employed in optical Diesel engines due to laser diagnostic constraints. However, these fuels generally differ from standard Diesel fuel in terms of cetane number and fuel volatility which can significantly influence the combustion and emissions characteristics in optical engines. These aspects have also been investigated within the present study. An improved understanding of the differences between optical and all-metal engines has allowed us to develop appropriate strategies to compensate for these differences on the optical engine. It is shown here that combustion phasing (and engine-out emissions matching between optical and all-metal engines can be achieved even for advanced LTC Diesel combustion strategies. The ability to ensure fully representative combustion and emissions behaviour of optical engines ultimately increases the value of optical engine data, highlighting the importance of using such engines as research tools for the further development of innovative, low emission combustion concepts. Les moteurs monocylindres transparents sont employés comme outils de recherche et de développement des moteurs à combustion interne. Ils permettent l’utilisation de techniques de diagnostics non-intrusifs (qualitatifs et quantitatifs pour étudier des phénomènes comme l’aérodynamique interne, la préparation du mélange, la combustion et la formation de polluants. Ces données expérimentales sont importantes pour la validation des modèles numériques et permettent également d’obtenir une compréhension détaillée des phénomènes physiques se déroulant dans la chambre. Les données recueillies aident au développement des nouvelles stratégies de combustion telles que la combustion homogène (HCCI et la combustion Diesel à basse température (LTC. Dans ce contexte, il est important

  14. Combustion Characteristics and Performance of Low-Swirl Injectors with Natural Gas and Alternative Fuels At Elevated Pressures and Temperatures

    Science.gov (United States)

    Beerer, David Joseph

    Stationary power-generating gas turbines in the United States have historically been fueled with natural gas, but due to its increasing price and the need to reduce carbon emissions, interest in alternative fuels is increasing. In order to effectively operate engines with these fuels their combustion characteristics need be well understood, especially at elevated pressures and temperatures. In this dissertation, the performance of blends of natural gas / methane with hydrogen and carbon dioxide, to simulate syngas and biogas, are evaluated in a model low-swirl stabilized combustor inside an optically accessible high-pressure vessel. The flashback and lean blow out limits, along with pollutant emissions, flow field, and turbulent displacement flame speeds, are measured as a function of fuel composition, pressure, inlet temperature, firing temperature, and flow rate in the range from 1 to 8 atm, 294 to 600K, 1350 to 1950K, and 20 to 60 m/s, respectively. These properties are quantified as a function of the inlet parameters. The lean blow-out limits are independent of pressure and inlet temperature but are weakly dependent on velocity. NOX emissions for both fuels were found to be exponentially dependent upon firing temperature, but emissions for the high-hydrogen flames were consistently higher than those of natural gas flames. The flashback limits for a 90%/10% (by volume) hydrogen/methane mixture increase with velocity and inlet temperature, but decrease with pressure. Correspondingly, the flame position progresses toward the combustor nozzle with increasing pressure and flame temperature, but away with increasing inlet temperature and velocity. Flashback occurred when the leading edge of the flame entered the nozzle. Local displacement turbulent flame speeds scale linearly with the turbulent fluctuating velocities, u', at the leading edge of the flame. Turbulent flame speeds for high-hydrogen fuels are twice that of natural gas for the same inlet conditions. The

  15. Internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Helmich, M.J.; Hoagland, M.C.; Hubbard, R.L.; Schaub, F.S.

    1981-12-22

    A method of combusting natural gas fuel in a two cycle, turbocharged internal combustion engine substantially reduces the production of nitrogen-oxygen emissions. An improved turbocharger design provides increased air charging pressure, produces a controlled lean air/fuel mixture and lowers peak combustion temperatures. A jet cell ignition device ensures uniform, reliable ignition of the lean air/fuel mixture under all operating conditions and the lean air/fuel mixture in turn encourages complete fuel combustion and provides excellent combustion characteristics with methane, ethane and heavier paraffinic hydrocarbon fuels. These structural modifications and adjustment of other operating parameters combine to reduce nitric oxide (NO) and nitrogen dioxide (NO/sub 2/) emissions by as much as 75% while effecting only a negligible increase in fuel consumption.

  16. Physical and combustion characteristics of biomass particles prepared by different milling processes for suspension firing in utility boilers

    DEFF Research Database (Denmark)

    Yin, Chungen; Momenikouchaksaraei, Maryam; Kær, Søren Knudsen

    2016-01-01

    close to suspension-fired boilers. The ignition, devolatilization and burnout times of the milled particles under different combustion conditions are analysed. A one-dimensional transient model, properly accounting for the particle-ambient flow interaction and appropriately addressing the key sub...

  17. Estimation of trapped mass by in-cylinder pressure resonance in HCCI engines

    Science.gov (United States)

    Luján, José Manuel; Guardiola, Carlos; Pla, Benjamín; Bares, Pau

    2016-01-01

    High pressure gradients at homogeneous charge compression ignition (HCCI) engines heavily excite the pressure resonance. The pressure resonant frequency depends on speed of sound in the cylinder, and thus on the bulk gas temperature. Present paper profits this relation estimating the trapped mass inside the cylinder. In contrast to other estimation methods in the literature, the presented method is based on the trace of the in-cylinder pressure during the cycle; therefore, it permits a cycle-to-cycle mass estimation, and avoids errors associated with other assumptions, such as heat transfer during compression or initial temperature of the in-cylinder gases. The proposed strategy only needs the pressure signal, a volume estimation and a composition assumption to obtain several trapped mass estimates during one cycle. These estimates can be later combined for providing an error estimate of the measurement, with the assumption of negligible blow-by. The method is demonstrated in two HCCI engines of different size, showing good performance in steady operation and presenting great potential to control transient operation.

  18. Homojen Karışımlı Sıkıştırma Ateşlemeli (HCCI bir motorun tek-bölgeli modelleme yöntemi kullanılarak analizi

    Directory of Open Access Journals (Sweden)

    Halit Yaşar

    2016-12-01

    Full Text Available HCCI motorların modellenmesinde sıfır-boyutlu modeller yaygın olarak kullanılmaktadır. Bu modeller tek veya çok bölge içerebilirler. Bununla birlikte, en basit yaklaşım yanmış ve yanmamış gazı içeren tek bölge yaklaşımıdır. Bu tip sıfır-boyutlu modellerde yanma olayı Wiebe fonksiyonu ile modellenmektedir. Bu makalede, HCCI prensibine göre çalışan tek silindirli bir Ricardo Hydra motoru tek bölge yaklaşımı kullanılarak modellenmiştir. Analiz çalışmalarında SPICE (Simulated Petrol Internal Combustion Engine yazılımının modifiye edilmiş bir versiyonu olan TRICE yazılımı kullanılmıştır. Yanma analizlerinde, HCCI yanma modellerinde standart Wiebe fonksiyonu kullanımının maksimum silindir basıncının yüksek olarak tahmin edilmesi sonucunu doğurması nedeniyle, standart Wiebe fonksiyonunun modifiye edilmiş bir şekli olan Double-Wiebe fonksiyonu kullanılmıştır. Analizler, n-Heptan-Toluen karışımı için üç hava fazlalık katsayısı değerinde gerçekleştirilmiş ve elde edilen sonuçlar bir Avrupa Komisyonu Marie Curie destek programı (FP-6 projesi kapsamında Shell Araştırma Merkezine ait motor test laboratuvarında ölçülen deneysel verilerle karşılaştırılmıştır.

  19. 某重型燃气轮机的燃烧特性分析%Analysis on Combustion Characteristics of a Heavy Duty Gas Turbine

    Institute of Scientific and Technical Information of China (English)

    王力军; 杨海峰; 孙远伟; 阴松凯

    2014-01-01

    为了深入研究某重型燃气轮机燃烧室的燃烧性能,在燃烧性能试验基础上,本文建立了包括扩压器、旋流器、火焰筒等部件在内的环管燃烧室全尺寸UG模型和数学模型。用Realizable k-ε湍流模型模拟气相湍流流动,离散项(DPM)模型用以模拟柴油雾化颗粒的随机运动,燃烧化学反应与湍流间的耦合采用EDC多步反应模型预测,压力与速度耦合计算采用SIMPLE算法。在与试验相同的操作条件下,对环管燃烧室的两相流流动、燃烧、传热过程以及燃烧性能进行了3种负荷状态下的CFD数值模拟。计算结果与试验值相符合。对比分析所得结论为改进燃烧室设计和燃烧室性能改善提供了依据。%For intensive studying combustion characteristics of a heavy-duty gas turbine combustor, full-scale UG and mathematics models of one-tube combustor are developed including components of gas turbine diffuser , swirler and flame tube based on its combus-tion performance trail.Realizable k-εturbulence model is used to simulate turbulent gas flow , DPM model is employed in modeling at-omized particles random movement of light diesel , EDC multistep reaction model is adopted for the coupling prediction of combustion reaction and turbulence, and SIMPLE algorithm is used for coupling calculation of pressure and velocity .The process of two-phase flow, combustion, heat transfer and combustion performance of three load types are CFD simulated under the same operating conditions with the trail.Calculated results are consistent with the experiment .The conclusions by comparing analysis give the basis of combustor design and its combustion performance improvement .

  20. Numerical Simulation of Combustion Characteristics of a 300 MW Blast Furnace Gas/Pulverized Coal Combined Combustion Boiler%300MW煤粉/高炉煤气混燃锅炉燃烧特性数值模拟

    Institute of Scientific and Technical Information of China (English)

    王春波; 魏建国; 盛金贵; 李艳奇

    2012-01-01

    Blast furnace gas(BFG) produced from steel mill is a low heat value fuel,which combined with pulverized coal to combust in boiler is one of effective ways.However,the combustion characteristics would be changed greatly when compared with only pulverized coal combustion.For example,superheaters and reheaters are easy to excess rated temperatures and carbon content in fly ash will become higher,etc.All these problems lead to its limited application today.Take a 300MW BFG/pulverized coal boiler for example,the combustion characteristics were simulated by means of two mixture fractions way.The pure coal condition and three BFG ratio: 10%,20% and 30% conditions were investigated.It shows the temperature level in boiler is lowered obviously when BFG was mixed into boiler.For example,the maximal temperature is lowered about 81K when BFG ratio is 10% for a boiler section.Also,the temperature becomes lower with the BFG ratio.When BFG was mixed into boiler the flue gases volume would be increased.So,the actual stay time for pulverized coal in boiler will be shortened and it is more difficulty for coal to combust completely.Aslo,it is helpfully for control NO emission when BFG was mixed into boiler.%钢厂高炉煤气是一种低热值燃料,它和煤粉在炉内掺烧是其一种有效的利用途径。但煤粉掺烧高炉煤气后燃烧特性与纯煤粉燃烧有很大不同,掺烧过程中易发生过/再热器超温、飞灰含碳量过高等问题,导致其在大型锅炉上的应用很少。针对某钢厂300MW四角切圆煤粉/高炉煤气混燃锅炉,使用二混合分数法对其燃烧特性进行数值模拟。对比研究了纯燃煤工况和高炉煤气掺烧量分别为10%、20%、30%的工况,发现掺烧高炉煤气时炉内温度水平有明显下降(如,掺烧10%高炉煤气时截面最高温度降低81K),且随着掺烧量的增加而加剧,但下降的趋势变缓。掺烧高炉煤气后产生烟气量增多,炉膛出口烟速有明显增加,

  1. Modeling of scalar dissipation rates in flamelet models for low temperature combustion engine simulations

    CERN Document Server

    Gupta, Saurabh; Pal, Pinaki; Im, Hong G

    2014-01-01

    The flamelet approach offers a viable framework for combustion modeling of homogeneous charge compression ignition (HCCI) engines under stratified mixture conditions. Scalar dissipation rate acts as a key parameter in flamelet-based combustion models which connects the physical mixing space to the reactive space. The aim of this paper is to gain fundamental insights into turbulent mixing in low temperature combustion (LTC) engines and investigate the modeling of scalar dissipation rate. Three direct numerical simulation (DNS) test cases of two-dimensional turbulent auto-ignition of a hydrogen-air mixture with different correlations of temperature and mixture fraction are considered, which are representative of different ignition regimes. The existing models of mean and conditional scalar dissipation rates, and probability density functions (PDFs) of mixture fraction and total enthalpy are a priori validated against the DNS data.

  2. Examining flow-flame interaction and the characteristic stretch rate in vortex-driven combustion dynamics using PIV and numerical simulation

    KAUST Repository

    Hong, Seunghyuck

    2013-08-01

    In this paper, we experimentally investigate the combustion dynamics in lean premixed flames in a laboratory scale backward-facing step combustor in which flame-vortex driven dynamics are observed. A series of tests was conducted using propane/hydrogen/air mixtures for various mixture compositions at the inlet temperature ranging from 300K to 500K and at atmospheric pressure. Pressure measurements and high speed particle image velocimetry (PIV) are used to generate pressure response curves and phase-averaged vorticity and streamlines as well as the instantaneous flame front, respectively, which describe unsteady flame and flow dynamics in each operating regime. This work was motivated in part by our earlier study where we showed that the strained flame consumption speed Sc can be used to collapse the pressure response curves over a wide range of operating conditions. In previous studies, the stretch rate at which Sc was computed was determined by trial and error. In this study, flame stretch is estimated using the instantaneous flame front and velocity field from the PIV measurement. Independently, we also use computed strained flame speed and the experimental data to determine the characteristic values of stretch rate near the mode transition points at which the flame configuration changes. We show that a common value of the characteristic stretch rate exists across all the flame configurations. The consumption speed computed at the characteristic stretch rate captures the impact of different operating parameters on the combustor dynamics. These results suggest that the unsteady interactions between the turbulent flow and the flame dynamics can be encapsulated in the characteristic stretch rate, which governs the critical flame speed at the mode transitions and thereby plays an important role in determining the stability characteristics of the combustor. © 2013 The Combustion Institute.

  3. Combustion characteristics in a municipal solid waste incinerator. 1st Report. ; Field test and computer simulation for combustion characterization. Toshi gomi shokyakuro ni okeru nensho tokusei. 1. ; Nensho jotai haaku no tame no jikken to simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ishimi, T.; Higashimura, K. (Kubota Corp., Osaka (Japan)); Koyama, M.; Hirayama, N. (Chiba Institute of Technology, Chiba (Japan))

    1994-05-25

    For suppressing and controlling the emission of dioxins in the flue gas from the city garbage incinerator, it is necessary to perform the complete combustion. The combustion state in the incinerator was investigated to understand the influence of combustion factors on the combustion. A computer simulation analysis on the gas flow in the incinerator was also carried out. The concentration of CO and O2 in the combustion gas leaving the incinerator and the temperature distribution in the incinerator were measured. The results showed that the atmosphere in the incinerator was distinctly separated into two zones, i.e., the high temperature zone where the O2 concentration was extremely low while the CO concentration exhibited its peak value and the low temperature zone where the CO concentration was relatively low and O2 concentration was excessively high. The effect of combustion gas temperature on the combustion reaction of unburnt gas was found to be high. When the combustion gas temperature was elevated, the CO concentration in the exhaust gas leaving the electrostatic precipitator was exponentially decreased. The relationship between the CO concentration and the O2 concentration could be expressed in a quadratic equation. There was a certain optimum O2 optimal concentration range for reducing the CO concentration. The O2 concentration was an important factor for controlling the combustion. The result of computer simulation proved to be shown well the combustion gas flow in the incinerator. 8 refs., 10 figs., 4 tabs.

  4. Emission characteristics of double swirl combustion system in diesel engine%柴油机双卷流燃烧系统的排放特性

    Institute of Scientific and Technical Information of China (English)

    孙柏刚; 谢均; 柴国英; 赵建辉; 李向荣

    2013-01-01

    The emission of diesel engines, to some extent, restricted the development of the diesel engine industry. Due to the importance of the combustion system of the diesel engine, there is a growing concern to reduce harmful emissions by improving the combustion system. Many factors influence on the engine performance and emissions, but the shape of the combustion chamber of direct injection diesel engine has a very important influence on the combustion process and the generation of harmful emissions. For Double Swirl Combustion System research focuses on reducing the detonation pressure, fuel consumption and the numerical simulation of spray mixing mechanism, and its emission characteristics of a few. To take Test and CFD simulation method to explore the fuel injection system, fuel injection timing, nozzle diameter, spray angle and swirl ratio to influence of emission characteristics of double swirl combustion system (DSCS). The results show that:with the increase of the fuel injection advance angle and the nozzle diameter decreases, NOx production increases, soot formation was reduced. Because the ignition delay period of cylinder mixture was increased with the increase in injection advance angle, the oil and gas mixing quality is improved with the increase in the ignition delay period, thus making the cylinder to an increase in the maximum combustion temperature. The temperature of the main factors of NOx generated, so NOx formation increases with the increase in injection advance angle. The reasons for the reduction of soot are the increase of the ignition delay period such that the cylinder fuel mixture better, reducing soot generation. With the increase in the diameter of the spray hole, the cylinder fuel quality deterioration, resulting in insufficient combustion produce soot emissions. With the increases in the angle of spray, soot formation was reduced, the amount of NOx first increases and then decreased. Excessively large spray angle and arc ridge, resulting

  5. Influence of temperature conditions in outer space on the macrokinetic characteristics of ignition and combustion of the solid-fuel charge of the microthruster of a microelectromechanical system

    Science.gov (United States)

    Futko, S. I.; Bondarenko, V. P.; Dolgii, L. N.

    2012-03-01

    On the basis of macrokinetic calculations, the influence of the initial temperature on the impulse responses of the processes of ignition and combustion of the solid-fuel charge of the microelectromechanical system (MEMS) microthruster burning the solid fuel glycidyl azide polymer (GAP)/RDX has been investigated. It has been established that fuel heating/cooling in a wide range of temperature values from 150 to 450 K characteristic of the conditions of a satellite in orbital flight markedly affects both the thrust and the total impulse of the MEMS microthruster. In so doing, an increase in the initial temperature leads to a marked decrease in the induction period and an increase in the critical flux of fuel ignition. The influence of the change in the initial temperature on the self-ignition temperature of GAP can be neglected. To obtain stable characteristics of the microthruster, it seems expedient to use a thermostating system.

  6. Combustion Characteristics and Road Test of Diesel/Methanol Compound Combustion%柴油/甲醇组合燃烧特性及道路试验研究

    Institute of Scientific and Technical Information of China (English)

    魏立江; 姚春德; 刘军恒; 姚安仁

    2012-01-01

    在一台单缸增压中冷试验发动机上,研究了高转速下柴油/甲醇组合燃烧(DMCC)模式的缸内燃烧特性,结果表明DMCC模式具有预混燃烧比例成倍增加,燃烧持续时间大大缩短的特点;另外,DMCC模式的放热中心时刻提前,排气温度降低,热效率相比纯柴油模式得到大比例提高。在一辆重型卡车上进行了DMCC模式的道路试验,发现DMCC模式甲醇对柴油的替代率达到了28.28%,替换比仅为1.36,百公里平均燃料效率提高了11.15%。%The combustion characteristics of diesel/methanol compound combustion(DMCC) mode at high engine speed were investigated on a single cylinder turbocharged and intercooled testingengine. The research found that the DMCC mode had the following characteristics:the proportion of premixed combustion increased double,and the duration of burning became shorter.Besides,the centre of the heat release rate curve moved near to TDC,the exhaust temperature decreased when DMCC mode was applied,and the thermal efficiency was significantly improved compared to pure diesel mode.Road tests of DMCC mode were also carried out on a heavy truck.The test results showed that the substitution ratio of methanol to diesel reached to 28.28%,the exchange ratio was just 1.36,and the mean fuel efficiency per 100 km was improved by 11.15%.

  7. Quantifying of the Thermal Dynamic Characteristics of the Combustion System for Underground Coal Fire and its Impact on Environment in Xinjiang region, China

    Science.gov (United States)

    ZENG, Qiang; Tiyip, Tashpolat; Wuttke, Manfred; NIE, Jing; PU, Yan

    2015-04-01

    Underground Coal fire (UCF) is one disaster associated with coal mining activities around the world. The UCF not only burns up the coal reservoir, but also causes serious environmental problems, such as the pollution to air, the damage to soils, and the contamination to surface and underground water and consequently the health problem to human beings. In the present paper, the authors attempts to quantify the thermal dynamic characteristics of the combustion system for UCF and its impact on environment by modeling, including delineating the physical boundary of UCF zone, modeling of the capacity of the oxygen supply to UCF, modeling the intensity of heat generation from UCF and modeling the process of heat transfer within UCF and its surrounding environment. From this research, results were obtained as follows: First of all, based on the rock control theory, a model was proposed to depict the physical boundary of UCF zone which is important for coal fire research. Secondly, with analyzing the characteristics of air and smoke flow within UCF zone, an air/smoke flow model was proposed and consequently a method was put forward to calculate the capacity of oxygen supply to the UCF. Thirdly, with analyzing the characteristics of coal combustion within UCF zone, a method of calculating the intensity of heat generation from UCF, i.e., the heat source models, was established. Heat transfer with UCF zone includes the heat conductivity within UCF zone, the heat dissipation by radiation from the surface of fire zone, and the heat dissipation by convection as well as the heat loss taken away by mass transport. The authors also made an effort to depict the process of heat transfer by quantitative methods. Finally, an example of Shuixigou coal fire was given to illustrate parts of above models. Further more, UCF's impact on environment, such as the heavy metals contamination to surface soil of fire zone and the characteristics of gaseous pollutants emission from the UCF also was

  8. 混合生物质颗粒燃料的燃烧特性%Combustion characteristics of composite biomass pellets

    Institute of Scientific and Technical Information of China (English)

    矫振伟; 赵武子; 王瀚平; 苏俊林

    2012-01-01

    The purpose of this study is to optimize the raw material composition of biomass pellets from cornstalk and rice husk by means of experimental optimization design and analysis, based on two key targets of ash melting characteristic and heat value. The optimum residue mixtures heighten the softening temperature over 1 400 ℃, which effectively improves the ashresidue properties of cornstalk pellets. Several types of analysis have been investigated in the paper by thermo -gravimetric experiment, combustion mechanism and dynamic characteristic for composite biomass pellets, the results show that composite biomass pellets are apt to ignite and have better performance of single peak pyrolysis and combustion characteristic. The results obtained here can be very useful for biomass fuel to improve the combustion characteristic, and can direct further development and application of biomass energy.%从生物质燃料的灰熔融性和热值两个关键性的特性指标着手,以玉米秸秆和水稻稻壳作为主要原料,用试验优化设计和分析的方法,寻求混合生物质颗粒燃料的优化配方,提高混合生物质颗粒的软化温度ST>1400℃,有效地解决了玉米秸秆颗粒结渣问题.对混合生物质颗粒进行了热重试验研究和燃烧机理、动力学特性分析,结果表明:混合生物质颗粒具有易着火和单峰值热解特性,燃烧性能良好.此研究为改善单一成分生物质燃料的燃烧性能,推广利用生物质能提供指导性建议.

  9. Computational Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C K; Mizobuchi, Y; Poinsot, T J; Smith, P J; Warnatz, J

    2004-08-26

    Progress in the field of computational combustion over the past 50 years is reviewed. Particular attention is given to those classes of models that are common to most system modeling efforts, including fluid dynamics, chemical kinetics, liquid sprays, and turbulent flame models. The developments in combustion modeling are placed into the time-dependent context of the accompanying exponential growth in computer capabilities and Moore's Law. Superimposed on this steady growth, the occasional sudden advances in modeling capabilities are identified and their impacts are discussed. Integration of submodels into system models for spark ignition, diesel and homogeneous charge, compression ignition engines, surface and catalytic combustion, pulse combustion, and detonations are described. Finally, the current state of combustion modeling is illustrated by descriptions of a very large jet lifted 3D turbulent hydrogen flame with direct numerical simulation and 3D large eddy simulations of practical gas burner combustion devices.

  10. Effect of diesel-biodiesel-ethanol blend on combustion, performance, and emissions characteristics on a direct injection diesel engine

    Directory of Open Access Journals (Sweden)

    Jamrozik Arkadiusz

    2017-01-01

    Full Text Available The paper presents results of co-combustion of diesel-biodiesel-ethanol fuel blend in direct injection Diesel engine. Test was performed at constant rotational speed at three commonly used loads of this engine: 100%, 85%, and 70% of load. During the test hydrated ethanol was used at a concentration of 89% of alcohol. In this study, the ethanol fuel was added to diesel-biodiesel fuel blend with concentrations up to 50% with the increment of 5%. The biodiesel was used as an additive to pre-vent the stratification of ethanol and diesel blends. Thermodynamic parameters of engine were analyzed, and combustion process and exhaust emission were characterized. It turned out that with the increase in engine load is possible to utilize larger ethanol fraction in blend. With the increase of ethanol fuel in blend the in-crease in ignition delay (38.5% for full load was observed, but burning duration decreased (49% for full load. The ethanol fuel share in blend generally causes the increase in NOx emission (42% for full load due to higher oxygen content and higher in-cylinder temperatures. It turned out that, at full load the unrepeatability of indicated mean effective pressure was near the same up to 50% of ethanol fuel in blend (about 2%. In case of partial load at higher ethanol fuel fraction the in-crease in indicated mean effective pressure un-repeatability was observed.

  11. EFFECTS OF SOME IMPREGNATION CHEMICALS ON COMBUSTION CHARACTERISTICS OF LAMINATED VENEER LUMBER (LVL PRODUCED WITH OAK AND POPLAR VENEERS

    Directory of Open Access Journals (Sweden)

    Seref Kurt

    2010-02-01

    Full Text Available The objective of this research was to investigate the effects of impregnation chemicals on the combustion properties of 3-ply laminated veneer lumber (LVL made of Oak (Quercus petraea subsp. İberica and Poplar (Populus tremula L.. For this purpose, oak wood was used as the outer ply and poplar used for the core ply in LVL. Borax (BX, boric acid (BA, borax+boric acid (BX+BA, and di-ammonium phosphate (DAP were used as impregnation chemicals, and urea formaldehyde (UF, phenol formaldehyde (PF, and melamine-urea-formaldehyde (MUF adhesives as bonding agent were used to produce LVLs. The vacuum – pressure method was used for the impregnation process. The combustion test was performed according to the procedure defined in the ASTM–E 69 standards, and during the test the mass reduction, temperature, and released gas (CO, O2 were determined for each 30 seconds. As a result, di-ammonium phosphate was found to be the most successful fire retardant chemical in LVL with MUF adhesive. LVL produced from a combination of oak and poplar veneers with MUF adhesive and impregnated with DAP can be recommended to be used as a fire resistant building material where required.

  12. Analysis of the characteristics of eight kinds of biomass pellet combustion%八种生物质颗粒燃烧特征分析

    Institute of Scientific and Technical Information of China (English)

    任敏娜; 崔永章; 李晓; 曲云霞; 张林华

    2012-01-01

    生物质成型颗粒燃料具有易储存、运输及使用方便、清洁环保、燃烧效率高等优点.本文通过实验得到八种生物质颗粒燃料的工业分析值,结合傅—张着火指标和缪岩燃烧特性指标分别计算出FZ和ZM值,得出装饰纸的着火温度最低,稻壳的着火温度最高.通过观察燃料燃烧后焚烧灰的形貌,指出在740~920℃温度范围内,生物质颗粒燃料燃烧后的灰颜色由黑逐渐变白,硬度由软逐渐变硬,甚至结焦渣.%The biomass pellet fuel is easy to store and transport, convenient to use, clean and helpful to environmental protection, and of high combustion efficiency. The study obtained the industry analysis values of eight kinds of biomass pellet fuels by experiment. Combined with fire indicator of Fu-Zhang and combustion characteristics indicator of Yan Niu, the study calculated the values of FZ and ZM and shows that the decorative paper has the minimum ignition temperature, while the rice husk has the highest ignition temperature. Finally, through the observation of the morphology of ash after the burning of fuel combustion, it is pointed out that with the increase of temperature from 740℃ to 920℃ , gray color of pellet fuel became gradually from black to white and hardness gradually hardened, even coke residue.

  13. Influence of the overfire air ratio on the NO(x) emission and combustion characteristics of a down-fired 300-MW(e) utility boiler.

    Science.gov (United States)

    Ren, Feng; Li, Zhengqi; Chen, Zhichao; Fan, Subo; Liu, Guangkui

    2010-08-15

    Down-fired boilers used to burn low-volatile coals have high NO(x) emissions. To find a way of solving this problem, an overfire air (OFA) system was introduced on a 300 MW(e) down-fired boiler. Full-scale experiments were performed on this retrofitted boiler to explore the influence of the OFA ratio (the mass flux ratio of OFA to the total combustion air) on the combustion and NO(x) emission characteristics in the furnace. Measurements were taken of gas temperature distributions along the primary air and coal mixture flows, average gas temperatures along the furnace height, concentrations of gases such as O(2), CO, and NO(x) in the near-wall region and carbon content in the fly ash. Data were compared for five different OFA ratios. The results show that as the OFA ratio increases from 12% to 35%, the NO(x) emission decreases from 1308 to 966 mg/Nm(3) (at 6% O(2) dry) and the carbon content in the fly ash increases from 6.53% to 15.86%. Considering both the environmental and economic effect, 25% was chosen as the optimized OFA ratio.

  14. Morphology and luminescence characteristics of combustion synthesized Y{sub 2}O{sub 3}: (Eu, Dy, Tb) nanoparticles with various amino-acid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, S.; Sudarsan, V. [Chemistry Division Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Sastry, P.U.; Patra, A.K. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Tyagi, A.K., E-mail: aktyagi@barc.gov.in [Chemistry Division Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2014-01-15

    Y{sub 2}O{sub 3} nanoparticles doped with Dy{sup 3+}, Eu{sup 3+} and Tb{sup 3+} together were prepared by the gel combustion method using a variety of amino acids namely, glycine, phenyl alanine, arginine, glutamic and aspartic acids. Number of carboxylate groups present in the amino acids used for combustion reaction was found to have strong influence on powder characteristics as well as luminescence from the samples. Based on small angle X-ray scattering studies, it is inferred that the nanoparticles prepared by using glycine and arginine as the fuels have smooth surface compared to those prepared using other amino acids. For the nanoparticles prepared using glutamic and aspartic acids, there exist a diffused pore-grain interface due to the lesser extent of heat generated in the reaction which leads to smaller particle size, poor crystallinity and improper burning of the organic materials. Lower surface area and smooth surface of the nanoparticles prepared using glycine leads to their improved luminescence properties. -- Highlights: • Surface smoothness of Y{sub 2}O{sub 3} (Dy, Eu, Tb) nanoparticles vary with amino acids. • Optimum luminescence intensity is observed when glycine is used as the fuel. • Diffused pore grain interface when glutamic and aspartic acids are used as fuels.

  15. Experimental study on effects of particle shape and operating conditions on combustion characteristics of single biomass particles

    DEFF Research Database (Denmark)

    Momenikouchaksaraei, Maryam; Yin, Chungen; Kær, Søren Knudsen

    2013-01-01

    An experimental study is performed to investigate the ignition, devolatilization, and burnout of single biomass particles of various shapes and sizes under process conditions that are similar to those in an industrial combustor. A charge-coupled device (CCD) camera is used to record the whole...... combustion process. For the particles with similar volume (mass), cylindrical particles are found to lose mass faster than spherical particles and the burnout time is shortened by increasing the particle aspect ratio (surface area). The conversion times of cylindrical particles with almost the same surface...... area/volume ratio are very close to each other. The ignition, devolatilization, and burnout times of cylindrical particles are also affected by the oxidizer temperature and oxygen concentration, in which the oxygen concentration is found to have a more pronounced effect on the conversion times at lower...

  16. Experimental Study on Effects of Particle Shape and Operating Conditions on Combustion Characteristics of Single Biomass Particles

    DEFF Research Database (Denmark)

    Momeni, M.; Yin, Chungen; Kær, Søren Knudsen

    2013-01-01

    An experimental study is performed to investigate the ignition, devolatilization, and burnout of single biomass particles of various shapes and sizes under process conditions that are similar to those in an industrial combustor. A chargecoupled device (CCD) camera is used to record the whole...... combustion process. For the particles with similar volume (mass), cylindrical particles are found to lose mass faster than spherical particles and the burnout time is shortened by increasing the particle aspect ratio (surface area). The conversion times of cylindrical particles with almost the same surface...... area/volume ratio are very close to each other. The ignition, devolatilization, and burnout times of cylindrical particles are also affected by the oxidizer temperature and oxygen concentration, in which the oxygen concentration is found to have a more pronounced effect on the conversion times at lower...

  17. PERFORMANCE, EMISSION AND COMBUSTION CHARACTERISTICS OF A METHYL ESTER SUNFLOWER OILEUCALYPTUS OIL IN A SINGLE CYLINDER AIR COOLED AND DIRECT INJECTION DIESEL ENGINE

    Directory of Open Access Journals (Sweden)

    TAMILVENDHAN.D,

    2011-03-01

    Full Text Available Biomass derived fuels are preferred as alternative fuels for IC engine due to its abundant availability and renewable nature. In the present work the performance, emission and combustion characteristics of a single cylinder constant speed , direct injection diesel engine using methyl ester of sun flower oil – eucalyptus oil blend as an alternative fuel were studied and the results are compared with thestandard diesel fuel operation. Result indicated that 50% reduction in smoke, 34% reduction in HC emission and a 37.5% reduction in CO emission for the MeS50Eu50 blend with 2.8 % increase in NOx emission at full load. Brake thermal efficiency was increased 2.7 % for eS50Eu50 blend.

  18. 城市生活垃圾燃烧特性研究%Study on Combustion Characteristic of Urban Domestic Refuse

    Institute of Scientific and Technical Information of China (English)

    陈国艳; 曾纪进; 段翠九

    2013-01-01

    By using the electricity and heat stove of fixed bed, the paper makes a study of combustion characteristic on urban domestic refuse. The study covers the paper, textile, kitchen surplus, tree branch, plastic and rubber etc. When the composed refuse pro rata are combusted, the flue gas characteristic changes with the change of temperature and excessive air coefficient. The result shows that the content of NOx increases fast, basical y moving up in line;the content of SO2 shows increasing trend gradual y. The increasing speed of NOx content sees slowness with the increase of excessive air coefficient, basical y moving up in line;and the content of SO2 shows decreasing trend gradual y.%  利用固定床电加热炉,对城市生活垃圾进行燃烧特性研究。研究由纸张、织物、厨余、树枝、塑料、橡胶等典型组分按比例组成的垃圾燃烧时,烟气特性随温度、过量空气系数的变化规律。结果表明:随着温度的升高,NOx的含量增加速度较快,基本上成直线上升;SO2的含量基本上也是呈逐步增加的趋势。随着过量空气系数的增加,NOx的含量增加速度较缓慢,基本上成直线上升;SO2的含量基本上呈逐步减少的趋势。

  19. HCCI发动机燃用MTBE/正庚烷混合燃料的燃烧和排放特性的研究%The Effect of MTBE Addition on the Combustion and Emission Characteristics of HCCI Engine with N-heptane Fuel

    Institute of Scientific and Technical Information of China (English)

    侯玉春; 吕兴才; 俎琳琳; 黄震

    2006-01-01

    对正庚烷及其与不同比例甲基叔丁基醚(MTBE)的混合燃料在高速4缸柴油机上进行单缸HCCI燃烧排放试验.试验结果表明,随着MTBE比例的增加,混合燃料的HCCI燃烧低温反应弱化并延迟,进而导致整个HCCI高温阶段燃烧被抑制,燃烧相位延迟,因而MTBE添加具有拓展正庚烷HCCI燃烧负荷的潜力.

  20. 某蒸发式稳定器燃烧特性及供油匹配数值研究%Numerical investigation on combustion characteristics and fuel supply matching for an evaporative flame-holder

    Institute of Scientific and Technical Information of China (English)

    丁兆波; 金捷

    2012-01-01

    为了研究一种适用于亚燃冲压发动机燃烧室的蒸发式火焰稳定器方案,采用PDF燃烧模型对其燃烧特性及供油匹配进行了流动及两相燃烧数值模拟与分析,重点研究了不同主燃区/局部供油匹配以及不同主燃区供油浓度分布等对燃烧性能的影响,获得了燃气温度峰值与均匀性相对优化的供油方案。%To study an evaporative flame-holder suitable for the ramjet combustor, the numerical simulation and analysis of two-phase combustion flow field for combustion characteristics and the fuel supply matching was carried out based on PDF combustion model. The influence of different main combustion zone / local fuel-feeding matching and fuel-feeding density distribution in different main combustion zone on the combustion performance were studied emphatically. An optimization fu- el-feeding scheme for peak value and uniformity of gas temperature were obtained. The calculation result of the scheme is rational. It has an important significance for the optimization design for the fuel-feeding scheme of the evaporative flame-holder.

  1. Flow characteristics of various swirl-can module designs. [exhaust flow simulation, flow characteristics, and combustion efficiency of jet engine fuels

    Science.gov (United States)

    Mularz, E. J.

    1975-01-01

    Flow measurements were performed on each of six swirl-can combustor module designs under simulated combustor operating conditions to find the design which exhibited a small recirculation zone, intense air mixing, and good fuel distribution in its wake. Conditions that are favorable for producing low oxides of nitrogen emissions and high combustion efficiency were investigated. The recirculation zone, the turbulence intensity and the fuel distribution pattern are obtained in the wake region of the center module of a three module array. The most promising swirl-can module design incorporates two air swirlers which discharge air in opposite directions (contraswirl), mixes the fuel and air upstream of the inner swirler, and has a flow area blockage of 64.3% for the three module array.

  2. Pooled effect of injection pressure and turbulence inducer piston on performance, combustion, and emission characteristics of a DI diesel engine powered with biodiesel blend.

    Science.gov (United States)

    Isaac JoshuaRamesh Lalvani, J; Parthasarathy, M; Dhinesh, B; Annamalai, K

    2016-12-01

    In this study, the effect of injection pressure on combustion, performance, and emission characteristics of a diesel engine powered with turbulence inducer piston was studied. Engine tests were executed using conventional diesel and 20% blend of adelfa biodiesel [A20]. The results acquired from renewable fuel A20 in the conventional engine showed reduction in brake thermal efficiency being the result of poor air fuel mixing characteristics and the higher viscosity of the tested fuel. This prompted further research aiming at the improvement of turbulence for better air fuel mixing by a novel turbulence inducer piston [TIP]. The investigation was carried out to study the combined effect of injection pressure and turbulence inducer piston. Considerable improvement in the emission characteristics like hydrocarbon, carbon monoxide, smoke was acheived as a result of optimised injection pressure. Nevertheless, the nitrogen oxide emissions were slightly higher than those of the conventional unmodified engine. The engine with turbulence inducer piston shows the scope for reducing the major pollution and thus ensures environmental safety.

  3. DOE Project 18546, AOP Task 1.1, Fuel Effects on Advanced Combustion Engines

    Energy Technology Data Exchange (ETDEWEB)

    Bunting, Bruce G [ORNL; Bunce, Michael [ORNL

    2012-01-01

    Research in 2011 was focused on diesel range fuels and diesel combustion and fuels evaluated in 2011 included a series of oxygenated biofuels fuels from University of Maine, oxygenated fuel compounds representing materials which could be made from sewage, oxygenated marine diesel fuels for low emissions, and a new series of FACE fuel surrogates and FACE fuels with detailed exhaust chemistry and particulate size measurements. Fuels obtained in late 2011, which will be evaluated in 2012, include a series of oil shale derived fuels from PNNL, green diesel fuel (hydrotreated vegetable oil) from UOP, University of Maine cellulosic biofuel (levulene), and pyrolysis derived fuels from UOP pyrolysis oil, upgraded at University of Georgia. We were able to demonstrate, through a project with University of Wisconsin, that a hybrid strategy for fuel surrogates provided both accurate and rapid CFD combustion modeling for diesel HCCI. In this strategy, high molecular weight compounds are used to more accurately represent physical processes and smaller molecular weight compounds are used for chemistry to speed chemical calculations. We conducted a small collaboration with sp3H, a French company developing an on-board fuel quality sensor based on near infrared analysis to determine how to use fuel property and chemistry information for engine control. We were able to show that selected outputs from the sensor correlated to both fuel properties and to engine performance. This collaboration leveraged our past statistical analysis work and further work will be done as opportunity permits. We conducted blending experiments to determine characteristics of ethanol blends based on the gasoline characteristics used for blending. Results indicate that much of the octane benefits gained by high level ethanol blending can be negated by use of low octane gasoline blend stocks, as allowed by ASTM D5798. This may limit ability to optimize engines for improved efficiency with ethanol fuels

  4. Combustion and emission characteristics of a dual fuel engine operated with mahua oil and liquefied petroleum gas

    Directory of Open Access Journals (Sweden)

    Nadar Kapilan N.

    2008-01-01

    Full Text Available For the present work, a single cylinder diesel engine was modified to work in dual fuel mode. To study the feasibility of using methyl ester of mahua oil as pilot fuel, it was used as pilot fuel and liquefied petroleum gas was used as primary fuel. In dual fuel mode, pilot fuel quantity and injector opening pressure are the few variables, which affect the performance and emission of dual fuel engine. Hence, in the present work, pilot fuel quantity and injector opening pressure were varied. From the test results, it was observed that the pilot fuel quantity of 5 mg per cycle and injector opening pressure of 200 bar results in higher brake thermal efficiency. Also the exhaust emissions such as smoke, unburnt hydrocarbon and carbon monoxide are lower than other pressures and pilot fuel quantities. The higher injection pressure and proper pilot fuel quantity might have resulted in better atomization, penetration of methyl ester of mahua oil and better combustion of fuel.

  5. A Study on Performance, Combustion and Emission Characteristics of Compression Ignition Engine Using Fish Oil Biodiesel Blends

    Science.gov (United States)

    Ramesha, D. K.; Thimmannachar, Rajiv K.; Simhasan, R.; Nagappa, Manjunath; Gowda, P. M.

    2012-07-01

    Bio-fuel is a clean burning fuel made from natural renewable energy resource; it operates in C. I. engine similar to the petroleum diesel. The rising cost of diesel and the danger caused to the environment has led to an intensive and desperate search for alternative fuels. Among them, animal fats like the fish oil have proven to be a promising substitute to diesel. In this experimental study, A computerized 4-stroke, single cylinder, constant speed, direct injection diesel engine was operated on fish oil-biodiesel of different blends. Three different blends of 10, 20, and 30 % by volume were used for this study. Various engine performance, combustion and emission parameters such as Brake Thermal Efficiency, Brake Specific Fuel Consumption, Heat Release Rate, Peak Pressure, Exhaust Gas Temperature, etc. were recorded from the acquired data. The data was recorded with the help of an engine analysis software. The recorded parameters were studied for varying loads and their corresponding graphs have been plotted for comparison purposes. Petroleum Diesel has been used as the reference. From the properties and engine test results it has been established that fish oil biodiesel is a better replacement for diesel without any engine modification.

  6. Structural, Optical, and Compactness Characteristics of Nanocrystalline CaNb2O6 Synthesized through an Autoigniting Combustion Method

    Directory of Open Access Journals (Sweden)

    K. C. Mathai

    2014-01-01

    Full Text Available Nanoparticles of calcium metaniobate compound are prepared by an autoigniting combustion technique and its structural, optical, and dielectric properties are investigated. The X-ray diffraction, Fourier-transform Raman, and infrared studies reveal that calcium metaniobate possesses phase pure orthorhombic columbite structure with space group of Pbcn. The average particle size of the as-prepared nanoparticles obtained from both the Scherrer formula and transmission electron microscopy is ~37 nm. The optical band gap calculated from Tauc's Plot is 3.25 eV. Photoluminescence studies reveal that Calcium metaniobate can be used as an idealphotoluminarmaterial. The powders are pelletised and sintered at an optimized temperature of 1350∘C in a short duration of two hours, yielding a high density. The morphology of the sintered pellet is further examined using scanning electron microscopy. The dielectric constant and loss factor values measured at 5 MHz for a well-sintered Calcium metaniobate pellet are found to be 27.6 and 5.3×10−4 respectively, at room temperature.

  7. Reduced chemical reaction mechanisms: experimental and HCCI modelling investigations of autoignition processes of iso-octane in internal combustion engines

    OpenAIRE

    Machrafi, Hatim; Lombaert, K.; Cavadias, S; Guibert, P.; Amouroux, J

    2005-01-01

    A semi-reduced (70 species, 210 reactions) and a skeletal (27 species, 29 reactions) chemical reaction mechanism for iso-octane are constructed from a semi-detailed iso-octane mechanism (84 species, 412 reactions) of the Chalmers University of Technology in Sweden. The construction of the reduced mechanisms is performed by using reduction methods such as the quasi-steady-state assumption and the partial equilibrium assumption. The obtained reduced iso-octane mechanisms show, at the mentioned ...

  8. Combustion Diagnostics by Pure Rotational Coherent Anti-Stokes Raman Scattering

    Science.gov (United States)

    Leipertz, Alfred; Seeger, Thomas

    Since its first use in Richard Chang's laboratory in 1982 in a comparative study with vibrational coherent anti-Stokes Raman scattering (VCARS) in a flame, pure rotational coherent anti-Stokes Raman scattering (RCARS) has gained tremendous importance for gas temperature and relative species concentration measurements in combustion diagnostics. The field of application covers basic studies on diagnostics development and on flame research as well as its use in technical combustion systems, e.g., for the determination of the gas-phase temperature in the vaporizing spray of a gasoline direct injection (GDI) injector or for the simultaneous measurement of gas temperature and exhaust-gas-recirculation rate (EGR rate) in a homogeneous charge compression ignition (HCCI) engine. An overview is given on the fundamentals of the technique and on its most important technical applications.

  9. Effects of Port Shape on Steady Flow Characteristics in an SI Engine with Semi-Wedge Combustion Chamber (2) - Velocity Distribution (2)

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Inkyoung; Ohm, Inyong [Seoul Nat’l Univ. of Science and Technology, Seoul (Korea, Republic of)

    2017-02-15

    This study is the second investigation on the steady flow characteristics of an SI engine with a semi-edge combustion chamber as a function of the port shape with varying evaluation positions. For this purpose, the planar velocity profiles were measured from 1.75B, 1.75 times of bore position apart from the bottom of head, to 6.00B positions using particle – image velocimetry. The flow patterns were examined with both a straight and a helical port. The velocity profiles, streamlines, and centers of swirl were almost the same at the same valve lift regardless of the measuring position, which is quite different from the case of the pent-roof combustion chamber. All the eccentricity values of the straight port were out of distortion criterion 0.15 through the lifts and the position. However, the values of the helical port exceeded the distortion criterion by up to 4 mm lift, but decreased rapidly above the 3.00B position and the 5 mm lift. There always existed a relative offset effect in the evaluation of the swirl coefficient using the PIV method due to the difference of the ideal impulse swirl meter velocity profile assumption, except for the cylinder-center-base estimation that was below 4 mm of the straight port. Finally, it was concluded that taking the center as an evaluation basis and the assumption about the axial velocity profile did not have any qualitative effect on swirl evaluation, but affected the value owing to the detailed profile.

  10. Combustion physics

    Science.gov (United States)

    Jones, A. R.

    1985-11-01

    Over 90% of our energy comes from combustion. By the year 2000 the figure will still be 80%, even allowing for nuclear and alternative energy sources. There are many familiar examples of combustion use, both domestic and industrial. These range from the Bunsen burner to large flares, from small combustion chambers, such as those in car engines, to industrial furnaces for steel manufacture or the generation of megawatts of electricity. There are also fires and explosions. The bountiful energy release from combustion, however, brings its problems, prominent among which are diminishing fuel resources and pollution. Combustion science is directed towards finding ways of improving efficiency and reducing pollution. One may ask, since combustion is a chemical reaction, why physics is involved: the answer is in three parts. First, chemicals cannot react unless they come together. In most flames the fuel and air are initially separate. The chemical reaction in the gas phase is very fast compared with the rate of mixing. Thus, once the fuel and air are mixed the reaction can be considered to occur instantaneously and fluid mechanics limits the rate of burning. Secondly, thermodynamics and heat transfer determine the thermal properties of the combustion products. Heat transfer also plays a role by preheating the reactants and is essential to extracting useful work. Fluid mechanics is relevant if work is to be performed directly, as in a turbine. Finally, physical methods, including electric probes, acoustics, optics, spectroscopy and pyrometry, are used to examine flames. The article is concerned mainly with how physics is used to improve the efficiency of combustion.

  11. Applied combustion

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-12-31

    From the title, the reader is led to expect a broad practical treatise on combustion and combustion devices. Remarkably, for a book of modest dimension, the author is able to deliver. The text is organized into 12 Chapters, broadly treating three major areas: combustion fundamentals -- introduction (Ch. 1), thermodynamics (Ch. 2), fluid mechanics (Ch. 7), and kinetics (Ch. 8); fuels -- coal, municipal solid waste, and other solid fuels (Ch. 4), liquid (Ch. 5) and gaseous (Ch. 6) fuels; and combustion devices -- fuel cells (Ch. 3), boilers (Ch. 4), Otto (Ch. 10), diesel (Ch. 11), and Wankel (Ch. 10) engines and gas turbines (Ch. 12). Although each topic could warrant a complete text on its own, the author addresses each of these major themes with reasonable thoroughness. Also, the book is well documented with a bibliography, references, a good index, and many helpful tables and appendices. In short, Applied Combustion does admirably fulfill the author`s goal for a wide engineering science introduction to the general subject of combustion.

  12. Investigation of the particle size distribution and particle density characteristics of Douglas fir hogged fuel fly ash collected under known combustion conditions. Technical Progress Report No. 2

    Energy Technology Data Exchange (ETDEWEB)

    Lang, A.J.; Junge, D.C.

    1978-12-01

    The increased interest in wood as a fuel source, coupled with the increasing demand to control the emission generated by wood combustion, has created a need for information characterizing the emissions that occur for given combustion conditions. This investigation characterizes the carbon char and inorganic fly ash size and density distribution for each of thirty-eight Douglas fir bark samples collected under known conditions of combustion.

  13. A comprehensive fractal char combustion model☆

    Institute of Scientific and Technical Information of China (English)

    Yuting Liu; Rong He

    2016-01-01

    The char combustion mechanisms were analyzed and a comprehensive fractal char combustion model was developed to give a better understanding and better predictions of the char combustion characteristics. Most of the complex factors affecting the char combustion were included, such as the coupling effects between the pore diffusion and the chemical reactions, the evolution of the char pore structures and the variation of the apparent reaction order during combustion, the CO/CO2 ratio in the combustion products and the correction for oxy-char combustion. Eleven different chars were then combusted in two drop tube furnaces with the conversions of the partly burned char samples measured by thermogravimetric analysis. The combustion processes of these chars were simulated with the predicted char conversions matching very well with the measured data which shows that this char combustion model has good accuracy. The apparent reaction order of the char combustion decreases, stabilizes and then increases during the combustion process. The combustion rates in the oxy-mode are general y slower than in the air-mode and the effect of the char-CO2 gasification reac-tion becomes obvious only when the temperature is relatively high and the O2 concentration is relatively low.

  14. Bifurcation Characteristics Analysis of Methane Combustion Process in CSTR%CSTR系统中甲烷燃烧过程的分岔特性分析

    Institute of Scientific and Technical Information of China (English)

    梁运涛; 曾文

    2011-01-01

    Bifurcation characteristics analysis of the combustion process of methane in a continuously-flow well-stirred tank reactor (CSTR) was carried out. The detailed chemical reaction mechanism of methane was adopted. The effects of system pressure, excessive air coefficient, system temperature and residence time on the bifurcation characteristics of the combustion process were discussed with system temperature and residence time as bifurcation parameters, respectively. There are two ignition points, namely partial ignition point and full ignition point, and three stages, including ignited branch, full ignited branch and extinguished branch, in the whole combustion process. When system temperature is adopted as bifurcation parameter, with the increase of system pressure, residence time gets prolonged, excessive air coefficient increasing, full ignition temperature decreases. When residence time is adopted as bifurcation parameter, with the increase of system pressure and temperature, residence time of full ignition is shortened. However, excessive air coefficient has little effect on residence time.%运用分岔理论对连续流动均匀搅拌反应器(CSTR)中甲烷燃烧过程的分岔特性进行了详细分析,采用了甲烷的详细化学反应机理.分别以系统温度、滞留时间为分岔参数,详细讨论了CSTR系统的各种工况(系统压力、混合气过量空气系数、系统温度及滞留时间)对甲烷燃烧过程分岔特性的影响.结果表明,在甲烷的整个燃烧过程中,出现了双着火点,即部分着火点和完全着火点;同时,出现了3个阶段,即部分着火阶段、完全着火阶段和熄火阶段.当以系统温度为分岔参数时,随着系统压力的升高、滞留时间的延长、过量空气系数的增加,甲烷的完全着火温度也随之降低.当以滞留时间为分岔参数时,随着系统温度、系统压力的升高,甲烷发生完全着火所需要的滞留时问随之缩短

  15. Experimental research on biomass particle combustion characteristics based on oxygen-enriched conditions%基于富氧条件的生物质颗粒燃烧特性实验研究

    Institute of Scientific and Technical Information of China (English)

    朱艳艳; 张林华; 崔永章; 李凯; 吕文超

    2013-01-01

    Oxygen-enriched combustion is an important method to solve the low temperature problem of biomass pellet fuel direct combustion. In order to study the combustion characteristics of biomass pellet fuel in the oxygen-enrich conditions, the paper utilizes thermal gravimetric analysis method to carry out combustion characteristics test about com stalks, cotton stalks and sawdust. Through the analysis of TG-DTG curves of three straws in different oxygen concentrations, we study the effect of oxygen-enriched conditions on combustion characteristics index of the three typical biomass pellet fuels. The results show that the burnout temperature interval of three biomass pellet fuels in the oxygen-enriched conditions reduced nearly 100 ℃ than that in the air, and fixed carbon combustion maximum rate is 2 -2. 75 times that in the air. In addition, fuel combustion characteristic index rises rapidly in the oxygen-enriched conditions, and the increase margin of corn stalk is the largest, so the promoting role of corn stalk is the strongest.%富氧燃烧是解决生物质能源直接燃烧温度低问题的重要方法.文章采用热重分析法分别对玉米、棉秆以及木屑进行燃烧特性试验,通过分析不同氧气浓度下三种秸秆的TG-DTG曲线,研究富氧条件对三种典型生物质颗粒燃料燃烧特性指数的影响.结果表明:富氧条件下三种生物质颗粒燃料燃尽温度区间比空气中减少近100℃,挥发分最大析出速率是空气中的2 ~2.75倍;富氧条件下,燃料的燃烧特性指数迅速上升,且玉米杆的上升幅度最大,表明富氧对玉米杆促进作用最强.

  16. Biofuels combustion.

    Science.gov (United States)

    Westbrook, Charles K

    2013-01-01

    This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly.

  17. Comparative study of the combustion characteristics of slot burner%缝隙式燃烧器燃烧特性对比研究分析

    Institute of Scientific and Technical Information of China (English)

    刘艳领; 陈玉忠

    2012-01-01

    The paper introduced varies of typical construction characteristics of the slot burner. Through comparative analysis of the stability, combustion economy, slagging property of the W - type flame boiler in different slot burner, the paper presented the improving direction of the slot burner, which layout the exhaust steam in the second tuyere near the center of the furnace health and layout the anti - slagging second wind in the primary wind front and rear wall side.%介绍了几种典型的缝隙式燃烧器的结构特点,通过对不同缝隙式燃烧器“W”火焰锅炉的燃烧稳定性、燃烧经济性、结渣特性的对比分析,指出了缝隙式燃烧器的改进方向,即乏汽应布置于靠炉膛中心侧的二次风喷口处,在一次风靠前后墙侧布置防结渣的二次风。

  18. The impact of combustion characteristics and flame structure on soot formation in oxy-enhanced and oxy-fuel diffusion flames

    Institute of Scientific and Technical Information of China (English)

    GUO; Zhe; LOU; Chun; LIU; ZhengDong; ZHOU; HuaiChun

    2013-01-01

    Based on a detailed chemical mechanism, impacts of combustion characteristics and flame structure on soot formation in opposed-flow diffusion ethylene flames was studied with different stoichiometric mixture fractions in O2/N2and O2/CO2atmospheres. The results showed the followings. 1) In both atmospheres, with the increase of stoichiometric mixture fraction, the flame structure changed significantly. The stagnation plane shifted toward the oxidizer side. Furthermore, there were less C2H2 but more O and OH to occur in the soot inception zone, therefore the amount of soot in the flame decreased. 2) Compared withN2, CO2had a suppression effect on soot formation, which was mainly due to thermal and direct chemical interaction effects of CO2. This is because the specific heat capacity of CO2is higher than that of N2, which will cause the flame temperature to drop,and mole fractions of C2H2, H, O, OH and main PAHs to decrease. Soot oxidation played a dominant role, while soot surface growth was attributed to the secondary position. Meanwhile, when CO2 abounded in the flame, OH concentration was increased through the backward reaction of CO+OH=CO2+H, and this would be conducive to the oxidation of soot precursor and incipient soot particles. In addition, the results of maximum particle density indicated the thermal effect of CO2on soot for-mation is more important than the direct chemical interaction effect.

  19. MODELING AND ANALYSIS OF PERFORMANCE, COMBUSTION AND EMMISSION CHARACTERISTICS OF JATROPHA METHYL ESTER BLEND DIESEL FOR CI ENGINE WITH VARIABLE COMPRESSION RATIO

    Directory of Open Access Journals (Sweden)

    S.ABINAV VISWANATH

    2012-07-01

    Full Text Available An experimental study was conducted on a four stroke single cylinder compression ignition engine to determine the performance, combustion and exhaust emission characteristics under different compression ratio using an alternate fuel. The raw oil from the jatropha seed was subjected to transesterification process and is supplied to the engine as jatropha methyl ester (JME blended with diesel. The blends used in our paper are 10%, 20% and 30%. We found that the performance of the engine under VCR is maximum at 20% blend for CR18. The fuelconsumption is also found to be increased with, a higher proportion of jatropha curcas oil in the blend. But BSFC is low at 20% JME-D. Emission was found to be optimum at CR18 for all blends of the methyl ester. At high engine load, the peak cylinder pressure was found to be higher for 20% JME-D under compression ratio 18. Using STAR CD software, three dimensional simulations are deployed and the results generated are compared against experimental output.

  20. Experimental investigation into effects of addition of zinc oxide on performance, combustion and emission characteristics of diesel-biodiesel-ethanol blends in CI engine

    Directory of Open Access Journals (Sweden)

    B. Prabakaran

    2016-12-01

    Full Text Available This study is to investigate the effect of zinc oxide nano particle addition to diesel-biodiesel-ethanol blends. Solubility tests were done for the fuels at three different temperatures. Out of eighteen blends, six blends were stable at 5 °C, 15 °C and above 25 °C. Out of the six blends, two blends were checked for properties as per ASTM standards. One of them was chosen for testing the performance, combustion and emission characteristics in a diesel engine. In the same blend, zinc oxide was added in the amount of 250 ppm. Property testing of the blended fuel indicated that there was an increase in calorific value due to addition of nano particle. The performance tests were conducted on a single cylinder four stroke direct injection diesel engine at a constant speed of 1500 rpm. For the blend containing zinc oxide, there was an increase in BSFC, HRR and cylinder pressure. Also, there was a decrease in BTE, NOx and smoke, as compared to diesel. The addition of zinc oxide nano particles increased the BTE and decreased the BSFC as compared with the biodiesel diesel ethanol blend at full load. This study gives a direction to utilize the renewable fuel to reduce the consumption of fossil fuel.

  1. Methods of Assessing the Resource of the Crankshaft Bearing of Internal Combustion Engine Based on the Calculation of Hydro-Mechanical Characteristics

    Directory of Open Access Journals (Sweden)

    I.G. Levanov

    2015-09-01

    Full Text Available The purpose of the article is to develop a tool to assess the theoretical resource crankshaft bearings of internal combustion engine. As a result, two methods for evaluating of the theoretical resource crankshaft bearings have been developed on the basis of the calculation of hydro-mechanical characteristics of bearings: the minimum film thickness and the extent of the zone of boundary friction. Under the theoretical resource of crankshaft bearing it is understood that during his work an increase of the radial clearance in the area of potential exposure (boundary friction is over the limit. The first technique is based on the bearing life dependence on the ratio between the minimum film thickness and its maximum allowable value. The second technique is based on the molecular-mechanical theory of friction and wear fatigue theory. Thus, these techniques may be used to estimate the resource of the crankshaft journal bearings at the design and finishing stage. However, some parameters of mathematical models have to be determined from the experimental test. The use of molecular-mechanical theory of friction and wear fatigue theory takes into account the influence of the physical and mechanical properties of a bearing material on his life.

  2. 氧体积分数对木质和玉米秸秆燃烧特性的影响%Effect of volume fraction of oxygen on combustion characteristics of wood pellets and corn stalks

    Institute of Scientific and Technical Information of China (English)

    彭好义; 姚昆; 蒋绍坚; 王育青; 彭福来

    2014-01-01

    采用TG-DTG-DSC联用技术对木质颗粒和玉米秸秆颗粒的燃烧特性进行了实验,考察了在不同含氧气氛中两种生物质的可燃特性、着火特性、燃烧稳定性、燃尽特性及综合燃烧特性的影响,计算了燃烧动力学参数。结果表明:随着氧体积分数的增大,两种生物质的着火温度和燃尽温度降低,燃烧稳定性判别指数、可燃性指数和综合燃烧特性指数增大;木质颗粒的着火温度和前期燃尽指数高于玉米秸秆,后期燃尽指数低于玉米秸秆,木质颗粒比玉米秸秆颗粒更难热分解,氧气体积分数对玉米秸秆颗粒燃烧特性影响要大于木质颗粒;生物质在低温阶段的活化能要大于高温阶段的活化能,两阶段的活化能随着氧气体积分数的增大而减小。%Thermo gravimetric experiments of corn stalks and wood pellets were performed by using TG-DTG-DSC thermal analysis technology. The effect of oxygen concentration on combustible characteristics,ignition characteristics,combustion stability characteristics,burn-out characteristics and synthetic combustion characteristics were discussed,and the combustion kinetics parameters were identified.Results show that with increase of oxygen concentration the ignition temperature,burn-out temperature decreased,the j udgement index of combustion stability,the combustible characteristics index and synthetic combustion characteristics index increased;the ignition temperature and the prophase burn-out characteristics index of wood pellets are higher than that of corn stalks,the later burn-out characteristics index is smaller than corn stalks,the wood pellets are more difficult to pyrolysis than corn stalks,the combustion characteristics of corn stalks is evidently affected by oxygen content.The corresponding reaction activation energy is larger at the low temperature phase than that at high temperature phase,the reaction activation energy of two stage decrease

  3. Control of Ignition and Combustion of Dimethyl Ether in Homogeneous Charge Compression Ignition Engine

    Science.gov (United States)

    Kim, Kyoung-Oh; Azetsu, Akihiko; Oikawa, Chikashi

    A homogeneous charge compression ignition (HCCI) engine is known to have high thermal efficiency and low nitrogen oxide emission. However, the control of ignition timing and its combustion period over a wide range of engine speeds and loads is one of the barriers to the realization of the engine. On the lean side of the equivalence ratio, control of ignition is difficult due to its long delay of ignition, and there is knocklike problem under high load. In both computations and experiments of HCCI engine operated on dimethyl ether, the operable range (the possible range of fuel input from just ignitable to knock-occurring state) shifted to the rich side with decreasing intake temperature and amount of mixing of carbon dioxide. The range of fuel input was reduced at low intake temperatures, because the hot flame onset angle advanced more quickly than it did at high intake temperatures. However, the mixing of CO2