WorldWideScience

Sample records for compressor unit failure

  1. Failure of the CAPS compressor(s). Final unusual occurrence report

    International Nuclear Information System (INIS)

    Kuechle, J.D.

    1981-01-01

    Acceptance testing of the CAPS compressors (4) was in progress which required periodic running of these units. Some vibration problems had occurred which required compressor shutdown for visual inspection and repair. During the performance of this visual inspection, it was decided to remove the crank case covers and to inspect the lower section of the cylinder liners for wear. The inspection revealed excessive scoring of the vertical cylinder liners on two of the four compressors that were opened. Acceptance testing of the CAPS compressors was suspended, pending further evaluation and repair

  2. Centrifugal Compressor Unit-based Heat Energy Recovery at Compressor Stations

    Directory of Open Access Journals (Sweden)

    V. S. Shadrin

    2016-01-01

    Full Text Available About 95% of the electricity consumed by air compressor stations around the world, is transformed into thermal energy, which is making its considerable contribution to global warming. The present article dwells on the re-use (recovery of energy expended for air compression.The article presents the energy analysis of the process of compressing air from the point of view of compressor drive energy conversion into heat energy. The temperature level of excess heat energy has been estimated in terms of a potential to find the ways of recovery of generated heat. It is shown that the temperature level formed by thermal energy depends on the degree of air compression and the number of stages of the compressor.Analysis of technical characteristics of modern equipment from leading manufacturers, as well as projects of the latest air compressor stations have shown that there are two directions for the recovery of heat energy arising from the air compression: Resolving technological problems of compressor units. The use of the excess heat generation to meet the technology objectives of the enterprise. This article examines the schematic diagrams of compressor units to implement the idea of heat recovery compression to solve technological problems: Heating of the air in the suction line during operation of the compressor station in winter conditions. Using compression heat to regenerate the adsorbent in the dryer of compressed air.The article gives an equity assessment of considered solutions in the total amount of heat energy of compressor station. Presented in the present work, the analysis aims to outline the main vectors of technological solutions that reduce negative impacts of heat generation of compressor stations on the environment and creating the potential for reuse of energy, i.e. its recovery.

  3. Study Improving Performance of Centrifugal Compressor In Paiton Coal Fired Power Plant Unit 1 And 2

    Science.gov (United States)

    Kusuma, Yuriadi; Permana, Dadang S.

    2018-03-01

    The compressed air system becomes part of a very important utility system in a Plant, including the Steam Power Plant. In PLN’S coal fired power plant, Paiton units 1 and 2, there are four Centrifugal air compressor types, which produce compressed air as much as 5.652 cfm and with electric power capacity of 1200 kW. Electricity consumption to operate centrifugal compressor is 7.104.117 kWh per year. This study aims to measure the performance of Centrifugal Compressors operating in Paiton’s coal fired power plant units 1 and 2. Performance Compressor is expressed by Specific Power Consumption (SPC) in kW/100 cfm. For this purpose, we measure the compressed air flow rate generated by each compressor and the power consumed by each compressor. The result is as follows Air Compressor SAC 2B : 15.1 kW/100 cfm, Air Compressor SAC 1B : 15.31 kW/100 cfm,Air Compressor SAC 1A : 16.3 kW/100 cfm and air Compressor SAC 2C : 18.19 kW/100 cfm. From the measurement result, air compressor SAC 2B has the best performance that is 15.1 kW / 100 cfm. In this study we analyze efforts to improve the performance of other compressors to at least match the performance of the SAC 2B air compressor. By increasing the Specific Power Consumption from others Compressor, it will get energy saving up to 284,165 kWh per year.

  4. Review on stress corrosion and corrosion fatigue failure of centrifugal compressor impeller

    Science.gov (United States)

    Sun, Jiao; Chen, Songying; Qu, Yanpeng; Li, Jianfeng

    2015-03-01

    Corrosion failure, especially stress corrosion cracking and corrosion fatigue, is the main cause of centrifugal compressor impeller failure. And it is concealed and destructive. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to the anodic dissolution (AD), the hydrogen-induced cracking (HIC), and the combined AD and HIC mechanisms. The corrosion behavior and the mechanism of corrosion fatigue in the crack propagation stage are similar to stress corrosion cracking. The effects of stress ratio, loading frequency, and corrosive medium on the corrosion fatigue crack propagation rate are analyzed and summarized. The corrosion behavior and the mechanism of stress corrosion cracking and corrosion fatigue in corrosive environments, which contain sulfide, chlorides, and carbonate, are analyzed. The working environments of the centrifugal compressor impeller show the behavior and the mechanism of stress corrosion cracking and corrosion fatigue in different corrosive environments. The current research methods for centrifugal compressor impeller corrosion failure are analyzed. Physical analysis, numerical simulation, and the fluid-structure interaction method play an increasingly important role in the research on impeller deformation and stress distribution caused by the joint action of aerodynamic load and centrifugal load.

  5. Refrigeration system with a compressor-pump unit and a liquid-injection desuperheating line

    Science.gov (United States)

    Gaul, Christopher J.

    2001-01-01

    The refrigeration system includes a compressor-pump unit and/or a liquid-injection assembly. The refrigeration system is a vapor-compression refrigeration system that includes an expansion device, an evaporator, a compressor, a condenser, and a liquid pump between the condenser and the expansion device. The liquid pump improves efficiency of the refrigeration system by increasing the pressure of, thus subcooling, the liquid refrigerant delivered from the condenser to the expansion device. The liquid pump and the compressor are driven by a single driving device and, in this regard, are coupled to a single shaft of a driving device, such as a belt-drive, an engine, or an electric motor. While the driving device may be separately contained, in a preferred embodiment, the liquid pump, the compressor, and the driving device (i.e., an electric motor) are contained within a single sealable housing having pump and driving device cooling paths to subcool liquid refrigerant discharged from the liquid pump and to control the operating temperature of the driving device. In another aspect of the present invention, a liquid injection assembly is included in a refrigeration system to divert liquid refrigerant from the discharge of a liquid pressure amplification pump to a compressor discharge pathway within a compressor housing to desuperheat refrigerant vapor to the saturation point within the compressor housing. The liquid injection assembly includes a liquid injection pipe with a control valve to meter the volume of diverted liquid refrigerant. The liquid injection assembly may also include a feedback controller with a microprocessor responsive to a pressure sensor and a temperature sensor both positioned between the compressor to operate the control valve to maintain the refrigerant at or near saturation.

  6. A Study on Estimating the Next Failure Time of Compressor Equipment in an Offshore Plant

    Directory of Open Access Journals (Sweden)

    SangJe Cho

    2016-01-01

    Full Text Available The offshore plant equipment usually has a long life cycle. During its O&M (Operation and Maintenance phase, since the accidental occurrence of offshore plant equipment causes catastrophic damage, it is necessary to make more efforts for managing critical offshore equipment. Nowadays, due to the emerging ICTs (Information Communication Technologies, it is possible to send health monitoring information to administrator of an offshore plant, which leads to much concern on CBM (Condition-Based Maintenance. This study introduces three approaches for predicting the next failure time of offshore plant equipment (gas compressor with case studies, which are based on finite state continuous time Markov model, linear regression method, and their hybrid model.

  7. Condensing Unit with a Scroll Compressor (UB series)

    Energy Technology Data Exchange (ETDEWEB)

    Editor, [Korea Energy Management Corporation, Yongin (Korea)

    2002-05-01

    Condensing unit, which is selected as a heat reservoir of grocery store or refrigerating warehouse, has increased its electricity consumption due to high annual operating ratio and large-sized stores. As the requirement of temperature management on freezing and storage has become strict for maintenance of food quality, the number of companies that import HACCP has increased for a few years. Accordingly, the requirement of high performance and reliability on a condensing unit has also risen more than it did. To meet the requirement, Mitsubishi Electric developed and sold condensing unit UB series, which has high reliability in energy saving. The company also has a plan to sell UPB series for the substitute refrigerant gas from fall of 2001. 5 figs., 2 tabs.

  8. Theoretical evaluation of the efficiency of gas single-stage reciprocating compressor medium pressure units

    Science.gov (United States)

    Busarov, S. S.; Vasil'ev, V. K.; Busarov, I. S.; Titov, D. S.; Panin, Ju. N.

    2017-08-01

    Developed earlier and tested in such working fluid as air, the technology of calculating the operating processes of slow-speed long-stroke reciprocating stages let the authors to obtain successful results concerning compression of gases to medium pressures in one stage. In this connection, the question of the efficiency of the application of slow-speed long-stroke stages in various fields of technology and the national economy, where the working fluid is other gas or gas mixture, is topical. The article presents the results of the efficiency evaluation of single-stage compressor units on the basis of such stages for cases when ammonia, hydrogen, helium or propane-butane mixture is used as the working fluid.

  9. Transient modeling of an air conditioner with a rapid cycling compressor and multi-indoor units

    International Nuclear Information System (INIS)

    Zhang Weijiang; Zhang Chunlu

    2011-01-01

    Rapid cycling the compressor is an alternative of the variable speed compressor to modulate the capacity of refrigeration systems for the purpose of energy saving at part-load conditions. The multi-evaporator air conditioner combined with the rapid cycling compressor brings difficulties in control design because of the sophisticated system physics and dynamics. In this paper the transient model of a multi-split air conditioner with a digital scroll compressor is developed for predicting the system transients under performance modulations. The predicted cycling dynamics are in good agreement with the experimental data. Based on the validated model, the impact of compressor idle power and cycle period to the part load performance is discussed.

  10. Transient modeling of an air conditioner with a rapid cycling compressor and multi-indoor units

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei-Jiang [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Zhang, Chun-Lu [College of Mechanical Engineering, Tongji University, 4800 Cao An Highway, Shanghai 201804 (China)

    2011-01-15

    Rapid cycling the compressor is an alternative of the variable speed compressor to modulate the capacity of refrigeration systems for the purpose of energy saving at part-load conditions. The multi-evaporator air conditioner combined with the rapid cycling compressor brings difficulties in control design because of the sophisticated system physics and dynamics. In this paper the transient model of a multi-split air conditioner with a digital scroll compressor is developed for predicting the system transients under performance modulations. The predicted cycling dynamics are in good agreement with the experimental data. Based on the validated model, the impact of compressor idle power and cycle period to the part load performance is discussed. (author)

  11. Transient modeling of an air conditioner with a rapid cycling compressor and multi-indoor units

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Weijiang [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Zhang Chunlu, E-mail: chunlu.zhang@carrier.utc.co [College of Mechanical Engineering, Tongji University, 4800 Cao An Highway, Shanghai 201804 (China)

    2011-01-15

    Rapid cycling the compressor is an alternative of the variable speed compressor to modulate the capacity of refrigeration systems for the purpose of energy saving at part-load conditions. The multi-evaporator air conditioner combined with the rapid cycling compressor brings difficulties in control design because of the sophisticated system physics and dynamics. In this paper the transient model of a multi-split air conditioner with a digital scroll compressor is developed for predicting the system transients under performance modulations. The predicted cycling dynamics are in good agreement with the experimental data. Based on the validated model, the impact of compressor idle power and cycle period to the part load performance is discussed.

  12. Insuring unit failures in electricity markets

    International Nuclear Information System (INIS)

    Pineda, S.; Conejo, A.J.; Carrion, M.

    2010-01-01

    An electric energy producer participates in futures markets in the hope of hedging the risk of trading in the pool. However, this producer is required to supply the energy associated with all its signed forward contracts even if some of its units are forced out due to unexpected failures. In this case, the producer must purchase some of the energy needed to meet its futures market commitments in the pool, which may result in high losses if the pool prices happen to be higher than the forward contract prices. To mitigate these losses, the producer can take out insurance against the forced outages of its units. Using a stochastic programming model, this paper analyzes the convenience of signing an insurance against unit failure by an electric energy producer and its impact on forward contracting decisions. Results from a realistic case study are provided and analyzed.

  13. Integrated Testing of a 4-Bed Molecular Sieve, Air-Cooled Temperature Swing Adsorption Compressor, and Sabatier Engineering Development Unit

    Science.gov (United States)

    Knox, James C.; Miller, Lee; Campbell, Melissa; Mulloth, Lila; Varghese, Mini

    2006-01-01

    Accumulation and subsequent compression of carbon dioxide that is removed from the space cabin are two important processes involved in a closed-loop air revitalization scheme of the International Space Station (ISS). The 4-Bed Molecular Sieve (4BMS) of ISS currently operates in an open loop mode without a compressor. The Sabatier Engineering Development Unit (EDU) processes waste CO2 to provide water to the crew. This paper reports the integrated 4BMS, air-cooled Temperature Swing Adsorption Compressor (TSAC), and Sabatier EDU testing. The TSAC prototype was developed at NASA Ames Research Center (ARC). The 4BMS was modified to a functionally flight-like condition at NASA Marshall Space Flight Center (MSFC). Testing was conducted at MSFC. The paper provides details of the TSAC operation at various CO2 loadings and corresponding performance of the 4BMS and Sabatier.

  14. Performance estimation of an oil-free linear compressor unit for a new compact 2K Gifford-McMahon cryocooler

    Science.gov (United States)

    Hiratsuka, Y.; Bao, Q.; Y Xu, M.

    2017-12-01

    Since 2012, a new, compact Gifford-McMahon (GM) cryocooler for cooling superconducting single photon detectors (SSPD) has been developed and reported by Sumitomo Heavy Industries, Ltd. (SHI). Also, it was reported that National Institute of Information and Communications Technology (NICT) developed a multi-channel, conduction-cooled SSPD system. However, the size and power consumption reduction becomes indispensable to apply such a system to the optical communication of AdHoc for a mobile system installed in a vehicle. The objective is to reduce the total height of the expander by 33% relative to the existing RDK-101 GM expander and to reduce the total volume of the compressor unit by 50% relative to the existing CNA-11 compressor. In addition, considering the targeted cooling application, we set the design cooling capacity targets of the first and the second stages 1 W at 60 K and 20 mW at 2.3 K respectively. In 2016, Hiratsuka et al. reported that an oil-free compressor was developed for a 2K GM cryocooler. The cooling performance of a 2K GM expander driven by an experimental unit of the linear compressor was measured. No-load temperature less than 2.1 K and the cooling capacity of 20 mW at 2.3 K were successfully achieved with an electric input power of only 1.1 kW. After that, the compressor capsule and the heat exchanger, etc. were assembled into one enclosure as a compressor unit. The total volume of the compressor unit and electrical box was significantly reduced to about 38 L, which was close to the target of 35 L. Also, the sound noise, vibration characteristics, the effect of the compressor unit inclination and the ambient temperature on the cooling performance, were evaluated. The detailed experimental results are discussed in this paper.

  15. Non-contact control of the working condition of mechanical units of the steam compressor for desalination plant

    Science.gov (United States)

    Danilin, A. I.; Chernyavsky, A. Zh.; Danilin, S. A.; Neverov, V. V.; Voroh, D. A.; Blagin, E. V.

    2018-03-01

    New methods and means for monitoring working condition of the rotating elements of steam compressor unit such as blade ring of the impeller and gears of multiplier are considered. Blade control is carried out by the signalling device of pre-emergency deformation of impeller blades. Control of the gears condition is carried out by apparatus system which allows to analyse change of the signal form caused by the gears wear. Influence of the wear types on the typical information parameters of the analysed signals is described. Technical characteristics of the devices and experimental research results are presented. Described control systems allow to detect deviations equal to 1-2% from initial condition. Application of such systems gives the opportunity to improve fault diagnosis and maintenance in 2-3 times.

  16. ANALYSIS AND PARAMETRIC OPTIMIZATION OF ENERGY-AND-TECHNOLOGY UNITS ON THE BASIS OF THE POWER EQUIPMENT OF COMPRESSOR PLANTS OF MAIN GAS PIPELINES

    Directory of Open Access Journals (Sweden)

    V. A. Sednin

    2017-01-01

    Full Text Available On the basis of the gas compressor units of compressor plants of a main gas pipeline mathematical models of the macro-level were generated for analysis and parametric optimization of combined energy-and-technology units. In continuation of the study these models was applied to obtain the regression dependencies. For this purpose, a numerical experiment was used which had been designed with the use of regression analysis mathematical tool, which assumes that the test results should represent independent, normally distributed, random variables with approximately equal variance. Herewith we study the dependence of the optimization criterion on the value of control parameters (factors. Planning, conducting and processing of results of the experiment was conducted in the following sequence: choice of the optimization criteria, selection of control parameters (factors, encoding factors, the matrix of experiment compiling, assessing significance of regression coefficients, testing the adequacy of the model and reproducibility of the experiments. As the optimization criteria the electricity capacity and efficiency of combined energy-technology units were adopted. As control parameters for the installation with a gas-expansion-and-generator machine the temperature of the fuel gas before the expander, the pressure of the fuel gas after the expander and the temperature of the air supplied to the compressor of the engine were adopted, while for the steam turbine the adopted optimization criteria were compression in the compressor of the engine, the steam consumption for the technology and the temperature of the air supplied to the compressor of the engine. The application of the outlined methodological approach makes it possible to obtain a simple polynomial dependence, which significantly simplify the procedures of analysis, parametric optimization and evaluation of efficiency in the feasibility studies of the options of construction of the energy

  17. Centrifugal compressor case study

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, B.

    2010-10-15

    Three centrifugal compressors at a pipeline station were retrofitted with higher head impellers in 2008. The owners of the station experienced vibration problems over the following 2 years that caused transmitter and position failures that were assumed to be flow-induced pulsations. A vibration and pulsation analysis indicated that the shell mode piping vibration excited by the blade pass pulsation was responsible for the failures. This study outlined factors that contributed to the vibration problem. Interferences between the compressor and shell mode piping natural frequencies were predicted, and potential excitation sources were examined. The study demonstrated how centrifugal vibration analyses can be used during the design phase to avoid costly adjustments. Recommendations included the addition of stiffeners to alter the shell modes, and the addition of constrained layer damping material to reduce resonant responses. 2 refs., 1 tab., 12 figs.

  18. Сomplex and protection vibrokontrolyu gas compressor units "visa-pc"

    Directory of Open Access Journals (Sweden)

    Е.П. Ясиніцький

    2006-01-01

    Full Text Available  Writers wanted to introduce and develop complex “Viza-PC” which meant for dimensioning and reflecting operation vibrofactors, forming the signal for tolerance buildup in system automatic control gascompressor unit.

  19. Observation unit management of acute decompensated heart failure.

    Science.gov (United States)

    Schrock, Jon W; Emerman, Charles L

    2009-01-01

    Acute decompensated heart failure (ADHF) is a common illness presenting to the emergency department (ED) that is amenable to observation unit (OU) treatment. As the number of baby boomers continues to grow and the incidence of heart failure increases, the financial implications of ADHF treatment will become more prominent. Obtaining institutional support and developing a good working relationship with cardiology colleagues is vital to creating workable ADHF protocols for whichever type of OU an institution decides to use.

  20. High frequency dynamics in centrifugal compressors

    NARCIS (Netherlands)

    Twerda, A.; Meulendijks, D.; Smeulers, J.P.M.; Handel, R. van den; Lier, L.J. van

    2008-01-01

    Problems with centrifugal compressors relating to high frequency, i.e. Blade passing frequency (BPF) are increasing. Pulsations and vibrations generated in centrifugal compressors can lead to nuisance, due to strong tonal noise, and even breakdown. In several cases the root cause of a failure or a

  1. Harmattan gas plant compressor conversion

    Energy Technology Data Exchange (ETDEWEB)

    Temple, K. [Altagas Ltd., Calgary, AB (Canada)

    2009-07-01

    The Harmattan Gas Plant located near the town of Didsbury, Alberta has typical processing units such as amine treating, sulfur recovery, refrigeration, and dehydration. In 1999, a deep cut turbo expander train was added for the extraction of ethane and in 2003 a spec carbon dioxide unit was added. Since its construction in 1961, the plant has undergone many modifications. As such, the plant is a mix of new and old equipment. A 3500 kW Solar Centaur 50LS gas turbine compressor with waste heat recovery was installed at the plant in 2008. This paper reviewed the project from concept to execution and demonstrated how reciprocating compressors were economically replaced with a gas turbine. Altagas had an incentive to invest in the project to lower operating and maintenance costs. Altagas was able to economically replace aging reciprocating compressors with a single turbine driving a centrifugal compressor without any producer subsidies or contract revisions. 2 tabs., 5 figs.

  2. Itegrated Test and Evaluation of a 4-Bed Molecular Sieve (4BMS) Carbon Dioxide Removtal System (CDRA), Mechanical Compressor Engineering Development Unit (EDU), and Sabitier Engineering Development Unit (EDU)

    Science.gov (United States)

    Knox, James C.; Campbell, Melissa; Murdoch, Karen; Miller, Lee A.; Jeng, Frank

    2005-01-01

    Currently on the International Space Station s (ISS) U.S. Segment, carbon dioxide (CO2) scrubbed from the cabin by a 4-Bed Molecular Sieve (4BMS) Carbon Dioxide Removal Assembly (CDRA) is vented overboard as a waste product. Likewise, the product hydrogen (H2) that will be generated by the Oxygen Generation Assembly (OGA) planned for installation will also be vented. A flight experiment has been proposed that will take the waste CO2 removed from the cabin, and via the catalytic Sabatier process, reduce it with waste H2 to generate water and methane. The water produced may provide cost and logistics savings for ISS by reducing the amount of water periodically re-supplied to orbit. To make this concept viable, a mechanical piston compressor and accumulator were developed for collecting and storing the CO2 from the CDRA. The compressor, accumulator and Sabatier system would be packaged together as one unit and referred to as the Carbon Dioxide Reduction Assembly (CRA). Testing was required to evaluate the performance of a 4BMS CDRA, compressor, accumulator, and Sabatier performance along with their operating rules when integrated together. This had been numerically modeled and simulated; however, testing was necessary to verify the results from the engineering analyses. Testing also allowed a better understanding of the practical inefficiencies and control issues involved in a fully integrated system versus the theoretical ideals in the model. This paper presents and discusses the results of an integrated engineering development unit test.

  3. Supersonic compressor

    Science.gov (United States)

    Roberts, II, William Byron; Lawlor, Shawn P.; Breidenthal, Robert E.

    2016-04-12

    A supersonic compressor including a rotor to deliver a gas at supersonic conditions to a diffuser. The diffuser includes a plurality of aerodynamic ducts that have converging and diverging portions, for deceleration of gas to subsonic conditions and then for expansion of subsonic gas, to change kinetic energy of the gas to static pressure. The aerodynamic ducts include vortex generating structures for controlling boundary layer, and structures for changing the effective contraction ratio to enable starting even when the aerodynamic ducts are designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of in excess of two to one, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

  4. Corrective Action Decision Document/Closure Report for Corrective Action Unit 559: T Tunnel Compressor/Blower Pad, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2010-03-15

    This Corrective Action Decision Document (CADD)/Closure Report (CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 559, T-Tunnel Compressor/Blower Pad. This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada, the U.S. Department of Energy, and the U.S. Department of Defense. Corrective Action Unit 559 is comprised of one Corrective Action Site (CAS): • 12-25-13, Oil Stained Soil and Concrete The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure in place with use restrictions for CAU 559.

  5. PURDU-WINCOF: A computer code for establishing the performance of a fan-compressor unit with water ingestion

    Science.gov (United States)

    Leonardo, M.; Tsuchiya, T.; Murthy, S. N. B.

    1982-01-01

    A model for predicting the performance of a multi-spool axial-flow compressor with a fan during operation with water ingestion was developed incorporating several two-phase fluid flow effects as follows: (1) ingestion of water, (2) droplet interaction with blades and resulting changes in blade characteristics, (3) redistribution of water and water vapor due to centrifugal action, (4) heat and mass transfer processes, and (5) droplet size adjustment due to mass transfer and mechanical stability considerations. A computer program, called the PURDU-WINCOF code, was generated based on the model utilizing a one-dimensional formulation. An illustrative case serves to show the manner in which the code can be utilized and the nature of the results obtained.

  6. Centrifugal Compressor Surge Controlled

    Science.gov (United States)

    Skoch, Gary J.

    2003-01-01

    It shows the variation in compressor mass flow with time as the mass flow is throttled to drive the compressor into surge. Surge begins where wide variations in mass flow occur. Air injection is then turned on to bring about a recovery from the initial surge condition and stabilize the compressor. The throttle is closed further until surge is again initiated. Air injection is increased to again recover from the surge condition and stabilize the compressor.

  7. Miniature Centrifugal Compressor

    Science.gov (United States)

    Sixsmith, Herbert

    1989-01-01

    Miniature turbocompressor designed for reliability and long life. Cryogenic system includes compressor, turboexpander, and heat exchanger provides 5 W of refrigeration at 70 K from 150 W input power. Design speed of machine 510,000 rpm. Compressor has gas-lubricated journal bearings and magnetic thrust bearing. When compressor runs no bearing contact and no wear.

  8. Development of ZL400 Mine Cooling Unit Using Semi-Hermetic Screw Compressor and Its Application on Local Air Conditioning in Underground Long-Wall Face

    Science.gov (United States)

    Chu, Zhaoxiang; Ji, Jianhu; Zhang, Xijun; Yan, Hongyuan; Dong, Haomin; Liu, Junjie

    2016-12-01

    Aiming at heat injuries occurring in the process of deep coal mining in China, a ZL400 mine-cooling unit employing semi-hermetic screw compressor with a cooling capacity of 400 kW is developed. This paper introduced its operating principle, structural characteristics and technical indexes. By using the self-built testing platform, some parameters for indication of its operation conditions were tested on the ground. The results show that the aforementioned cooling unit is stable in operation: cooling capacity of the unit was 420 kW underground-test conditions, while its COP (coefficient of performance) reached 3.4. To address the issue of heat injuries existing in No. 16305 U-shaped long-wall ventilation face of Jining No. 3 coal mine, a local air conditioning system was developed with ZL400 cooling unit as the system's core. The paper presented an analysis of characteristics of the air current flowing in the air-mixing and cooling mode of ZL400 cooling unit used in air intake way. Through i-d patterns we described the process of the airflow treatment, such as cooling, mixing and heating, etc. The cooling system decreased dry bulb temperature on working face by 3°C on average and 3.8°C at most, while lowered the web bulb temperature by 3.6°C on average and 4.8°C at most. At the same time, it reduced relative humidity by 5% on average and 8.6% at most. The field application of the ZL400 cooling unit had gain certain effects in air conditioning and provided support for the solution of mine heat injuries in China in terms of technology and equipment.

  9. Magentically actuated compressor

    Science.gov (United States)

    Evans, J.; Studer, P. A. (Inventor)

    1985-01-01

    A vibration free fluid compressor particularly adapted for Stirling cycle cryogenic refrigeration apparatus comprises a pair of identical opposing ferromagnetic pistons located in a housing and between a gas spring including a sealed volume of a working fluid such as gas under pressure. The gas compresses and expands in accordance with movement of the pistons to generate a compression wave which can be vented to other apparatus, for example, a displacer unit in a Stirling cycle engine. The pistons are urged outwardly due to the pressure of the gas; however, a fixed electromagnetic coil assembly located in the housing adjacent the pistons, is periodically energized to produce a magnetic field which interlinks the pistons in such a fashion that the pistons are mutually attracted to one another. The mass of the pistons, in conjunction with the compressed gas between them, form a naturally resonant system which, when the pistons are electromagnetically energized, produces an oscillating compression wave in the entrapped fluid medium.

  10. Compressors selection and sizing

    CERN Document Server

    Brown, Royce N

    2005-01-01

    This practical reference provides in-depth information required to understand and properly estimate compressor capabilities and to select the proper designs. Engineers and students will gain a thorough understanding of compression principles, equipment, applications, selection, sizing, installation, and maintenance. The many examples clearly illustrate key aspects to help readers understand the ""real world"" of compressor technology.Compressors: Selection and Sizing, third edition is completely updated with new API standards. Additions requested by readers include a new section on di

  11. The Compressor Recycle System

    OpenAIRE

    Barstad, Bjørn Ove

    2010-01-01

    The compressor recycle system is the main focus of this thesis. When the mass flow through a compressor becomes too low, the compressor can plunge into surge. Surge is a term that is used for axisymmetric oscillation through a compressor and is highly unwanted. The recycle system feeds compressed gas back to the intake when the mass flow becomes too low, and thereby act as a safety system.A mathematical model of the recycle system is extended and simulated in SIMULINK. The mathematical model ...

  12. High Efficiency Centrifugal Compressor for Rotorcraft Applications

    Science.gov (United States)

    Medic, Gorazd; Sharma, Om P.; Jongwook, Joo; Hardin, Larry W.; McCormick, Duane C.; Cousins, William T.; Lurie, Elizabeth A.; Shabbir, Aamir; Holley, Brian M.; Van Slooten, Paul R.

    2017-01-01

    A centrifugal compressor research effort conducted by United Technologies Research Center under NASA Research Announcement NNC08CB03C is documented. The objectives were to identify key technical barriers to advancing the aerodynamic performance of high-efficiency, high work factor, compact centrifugal compressor aft-stages for turboshaft engines; to acquire measurements needed to overcome the technical barriers and inform future designs; to design, fabricate, and test a new research compressor in which to acquire the requisite flow field data. A new High-Efficiency Centrifugal Compressor stage -- splittered impeller, splittered diffuser, 90 degree bend, and exit guide vanes -- with aerodynamically aggressive performance and configuration (compactness) goals were designed, fabricated, and subquently tested at the NASA Glenn Research Center.

  13. Real-time trend monitoring of gas compressor stations

    Energy Technology Data Exchange (ETDEWEB)

    Van Hardeveld, T. (Nova, an Alberta Corp., AB (Canada))

    1991-02-01

    The authors' company has developed a machinery health monitoring system (MHealth) for short-term and long-term historical trending and analysis of data from its 40 gas compressor stations. The author discusses the benefits of real-time trending in troubleshooting operations, in preventative maintenance scheduling and cites specific applications in the startup operations of several new gas compressor/centrifugal compressor units.

  14. High ratio recirculating gas compressor

    Science.gov (United States)

    Weinbrecht, J.F.

    1989-08-22

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

  15. Displacement compressors - acceptance tests

    CERN Document Server

    International Organization for Standardization. Geneva

    1996-01-01

    ISO 1217:2009 specifies methods for acceptance tests regarding volume rate of flow and power requirements of displacement compressors. It also specifies methods for testing liquid-ring type compressors and the operating and testing conditions which apply when a full performance test is specified.

  16. Reliability modelling for wear out failure period of a single unit system

    OpenAIRE

    Arekar, Kirti; Ailawadi, Satish; Jain, Rinku

    2012-01-01

    The present paper deals with two time-shifted density models for wear out failure period of a single unit system. The study, considered the time-shifted Gamma and Normal distributions. Wear out failures occur as a result of deterioration processes or mechanical wear and its probability of occurrence increases with time. A failure rate as a function of time deceases in an early failure period and it increases in wear out period. Failure rates for time shifted distributions and expression for m...

  17. [Lubricant-free piston compressors for mechanized medical instruments].

    Science.gov (United States)

    Sabitov, V Kh; Repin, V A; Kil'kinov, A A

    1988-01-01

    Piston compressor without lubrication with air blow to packing rings by plunger, disposed in subpiston space, is recommended as the basic scheme of construction of a power supply unit for medical pneumatic tooling. The construction reduces a leak of the compressive medium, increasing the efficiency of a compressor and seal reliability.

  18. Development of the virtual experimental bench on the basis of modernized research centrifugal compressor stage test unit with the 3D impeller.

    Science.gov (United States)

    Aksenov, A. A.; Danilishin, A. M.; Dubenko, A. M.; Kozhukov, Y. V.

    2017-08-01

    Design modernization of the centrifugal compressor stage test bench with three dimensional impeller blades was carried out for the possibility of holding a series of experimental studies of different 3D impeller models. The studies relates to the problem of joint work of the impeller and the stationary channels of the housing when carrying out works on modernization with the aim of improving the parameters of the volumetric capacity or pressure in the presence of design constraints. The object of study is the experimental single end centrifugal compressor stage with the 3D impeller. Compressor stage consists of the 3D impeller, vaneless diffuser (VLD), outlet collector - folded side scroll and downstream pipe. The drive is a DC motor 75 kW. The increase gear (multiplier) was set between the compressor and DC motor, gear ratio is i = 9.8. To obtain the characteristics of the compressor and the flow area the following values were measured: total pressure, static pressure, direction (angles) of the stream in different cross sections. Additional pneumometric probes on the front wall of the VLD of the test bench have been installed. Total pressure probes and foster holes for the measurement of total and static pressure by the new drainage scheme. This allowed carrying out full experimental studies for two elements of centrifugal compressor stage. After the experimental tests the comprehensive information about the performance of model stage were obtained. Was measured geometric parameters and the constructed virtual model of the experimental bench flow part with the help of Creo Parametric 3.0 and ANSYS v. 16.2. Conducted CFD calculations and verification with experimental data. Identifies the steps for further experimental and virtual works.

  19. Tests of cold helium compressors at Fermilab

    International Nuclear Information System (INIS)

    Peterson, T.J.; Fuerst, J.D.

    1988-01-01

    Fermilab has tested two compressors for possible installation in the satellite refrigerator buildings of the Tevatron cryogenic system. Both Creare Inc. and Cryogenic Consultants Inc. have supplied units for evaluation. The Creare machine, a high speed centrifugal pump/compressor, yielded 60% adiabatic efficiency but had difficulty withstanding two-phase flow. Cryogenic Consultants provided a reciprocating unit which achieved 59% efficiency and, although lacking the operating characteristics of the turbomachine, endured throughout testing and was insensitive to two-phase flow. Test results are discussed

  20. Failure investigation of stem of valve disc in reactor recirculation system of TAPS Unit-1

    International Nuclear Information System (INIS)

    Ramadasan, E.; Bahl, J.K.; Sivaramakrishnan, K.S.

    1986-01-01

    Failure analysis was carried out of failed 17-4 PH stainless steel stem of the valve disc in reactor recirculation system of Unit-1 of Tarapur Atomic Power Station. The examination revealed that the stem failed due to fatigue, accelerated by corrosion. Recommendations have been made to avoid such failures. (author)

  1. Evaluation of the european heart failure self-care behaviour scale in a united kingdom population

    NARCIS (Netherlands)

    Shuldham, Caroline; Theaker, Chris; Jaarsma, Tiny; Cowie, Martin R.

    2007-01-01

    Title. Evaluation of the European Heart Failure Self-care Behaviour Scale in a United Kingdom population Aim. This paper is a report of a study to test the internal consistency, reliability and validity of the 12-item European Heart Failure Self-care Behaviour Scale in an English-speaking sample in

  2. Classification and Quality Standards of Heart Failure Units: Scientific Consensus of the Spanish Society of Cardiology.

    Science.gov (United States)

    Anguita Sánchez, Manuel; Lambert Rodríguez, José Luis; Bover Freire, Ramón; Comín Colet, Josep; Crespo Leiro, María G; González Vílchez, Francisco; Manito Lorite, Nicolás; Segovia Cubero, Javier; Ruiz Mateas, Francisco; Elola Somoza, Francisco Javier; Íñiguez Romo, Andrés

    2016-10-01

    The prevalence of heart failure remains high and represents the highest disease burden in Spain. Heart failure units have been developed to systematize the diagnosis, treatment, and clinical follow-up of heart failure patients, provide a structure to coordinate the actions of various entities and personnel involved in patient care, and improve prognosis and quality of life. There is ample evidence on the benefits of heart failure units or programs, which have become widespread in Spain. One of the challenges to the analysis of heart failure units is standardization of their classification, by determining which "programs" can be identified as heart failure "units" and by characterizing their complexity level. The aim of this article was to present the standards developed by the Spanish Society of Cardiology to classify and establish the requirements for heart failure units within the SEC-Excellence project. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  3. Probabilistic analysis of Millstone Unit 3 ultimate containment failure probability given high pressure: Chapter 14

    International Nuclear Information System (INIS)

    Bickel, J.H.

    1983-01-01

    The quantification of the containment event trees in the Millstone Unit 3 Probabilistic Safety Study utilizes a conditional probability of failure given high pressure which is based on a new approach. The generation of this conditional probability was based on a weakest link failure mode model which considered contributions from a number of overlapping failure modes. This overlap effect was due to a number of failure modes whose mean failure pressures were clustered within a 5 psi range and which had uncertainties due to variances in material strengths and analytical uncertainties which were between 9 and 15 psi. Based on a review of possible probability laws to describe the failure probability of individual structural failure modes, it was determined that a Weibull probability law most adequately described the randomness in the physical process of interest. The resultant conditional probability of failure is found to have a median failure pressure of 132.4 psia. The corresponding 5-95 percentile values are 112 psia and 146.7 psia respectively. The skewed nature of the conditional probability of failure vs. pressure results in a lower overall containment failure probability for an appreciable number of the severe accident sequences of interest, but also probabilities which are more rigorously traceable from first principles

  4. Failure analysis of storage tank component in LNG regasification unit using fault tree analysis method (FTA)

    Science.gov (United States)

    Mulyana, Cukup; Muhammad, Fajar; Saad, Aswad H.; Mariah, Riveli, Nowo

    2017-03-01

    Storage tank component is the most critical component in LNG regasification terminal. It has the risk of failure and accident which impacts to human health and environment. Risk assessment is conducted to detect and reduce the risk of failure in storage tank. The aim of this research is determining and calculating the probability of failure in regasification unit of LNG. In this case, the failure is caused by Boiling Liquid Expanding Vapor Explosion (BLEVE) and jet fire in LNG storage tank component. The failure probability can be determined by using Fault Tree Analysis (FTA). Besides that, the impact of heat radiation which is generated is calculated. Fault tree for BLEVE and jet fire on storage tank component has been determined and obtained with the value of failure probability for BLEVE of 5.63 × 10-19 and for jet fire of 9.57 × 10-3. The value of failure probability for jet fire is high enough and need to be reduced by customizing PID scheme of regasification LNG unit in pipeline number 1312 and unit 1. The value of failure probability after customization has been obtained of 4.22 × 10-6.

  5. Hermetically Sealed Compressor

    Science.gov (United States)

    Holtzapple, Mark T.

    1994-01-01

    Proposed hermetically sealed pump compresses fluid to pressure up to 4,000 atm (400 MPa). Pump employs linear electric motor instead of rotary motor to avoid need for leakage-prone rotary seals. In addition, linear-motor-powered pump would not require packings to seal its piston. Concept thus eliminates major cause of friction and wear. Pump is double-ended diaphragm-type compressor. All moving parts sealed within compressor housing.

  6. Bruce NGS A Unit 4 preheater divider plate failure

    International Nuclear Information System (INIS)

    Landridge, M.; McInnes, D.

    1995-01-01

    On May 19, 1995, without any prior operational indications, Bruce A discovered preheater divider plate damage in Unit 4 that had the potential to have a major impact on the continued safe operation of the station. Further investigations indicated that Unit 4 may have been operating with this damage for as long as ten years. In the two months following the discovery, Bruce A has procured and replaced the 4 divider plates, located most of the missing pieces, retrieved pieces from the PHT system, investigated historical operational information, performed detailed analytical investigations, investigated root cause, performed in-situ and mock-up testing, updated operational procedures and installed DP monitoring equipment

  7. Cooled spool piston compressor

    Science.gov (United States)

    Morris, Brian G. (Inventor)

    1993-01-01

    A hydraulically powered gas compressor receives low pressure gas and outputs a high pressure gas. The housing of the compressor defines a cylinder with a center chamber having a cross-sectional area less than the cross-sectional area of a left end chamber and a right end chamber, and a spool-type piston assembly is movable within the cylinder and includes a left end closure, a right end closure, and a center body that are in sealing engagement with the respective cylinder walls as the piston reciprocates. First and second annual compression chambers are provided between the piston enclosures and center housing portion of the compressor, thereby minimizing the spacing between the core gas and a cooled surface of the compressor. Restricted flow passageways are provided in the piston closure members and a path is provided in the central body of the piston assembly, such that hydraulic fluid flows through the piston assembly to cool the piston assembly during its operation. The compressor of the present invention may be easily adapted for a particular application, and is capable of generating high gas pressures while maintaining both the compressed gas and the compressor components within acceptable temperature limits.

  8. Leak-tight compressor

    International Nuclear Information System (INIS)

    Bogomolova, L.K.; Vasilenko, A.T.

    1974-01-01

    The publication describes the construction and operating principle of the sealed uniflow compressor. This compressor insures against substantial contamination of the medium handled. Use of the slot-type sealing of the piston and rejection of the sliding bearings result in insuring high purity of the medium handled. The compressor performance is as follows: maximum air throughput - 262.6 1/h at 24 deg C and absolute outlet pressure being 1.14 kgf/cm 2 , minimum air throughput - 82.6 1/h at 24 deg C and absolute outlet pressure being 1.4 kgf/cm 2 ; inlet pressure equals 1 kgf/cm 2 . The compressor is provided with a solenoid-operated drive. The prototype has been in service for 6 months, with accumulated service time amounting to 500 h. The compressor has given a good account of itself within this period. The compressor is to be used in the gas purification circuit when this gas is used as a working medium in the spark or streamer chambers

  9. Investigation of a Rise in Obstetric Acute Renal Failure in the United States, 1999-2011.

    Science.gov (United States)

    Mehrabadi, Azar; Dahhou, Mourad; Joseph, K S; Kramer, Michael S

    2016-05-01

    To estimate whether the reported increase in obstetric acute renal failure in the United States was attributable to a concurrent rise in postpartum hemorrhage, a change in other risk factors, or changes in the diagnosis of acute renal failure. We conducted a retrospective cohort study to quantify temporal trends in acute renal failure among 10,969,263 hospital deliveries in the United States from 1999 to 2011 using data from the Nationwide Inpatient Sample. Dialysis and maternal death were used as markers of severe acute renal failure. Logistic regression was used to determine whether changes in risk factors explained the temporal rise in acute renal failure. Obstetric acute renal failure rose from 2.4 to 6.3 per 10,000 deliveries between 1999-2001 and 2010-2011, a 10% yearly increase (95% confidence interval [CI] 8-11%) and adjustment for risk factors only partially explained the rise (adjusted yearly increase 6%, 95% CI 5-8%). The overall severity of acute renal failure decreased, although acute renal failure with dialysis rose from 0.27 to 0.36 per 10,000 deliveries (P for trend=.01), and acute renal failure associated with maternal death increased from 0.13 to 0.23 per 10,000 deliveries (P for trend=.01). The temporal increase in acute renal failure with dialysis was abolished by adjustment for chronic kidney disease and chronic hypertension. Changes in diagnosis or ascertainment have led to substantial increases in obstetric acute renal failure, whereas increases in chronic kidney disease and chronic hypertension among pregnant women have resulted in modest but significant increases in acute renal failure with dialysis.

  10. Active compressor engine silencer reduces exhaust noise

    International Nuclear Information System (INIS)

    Denenberg, J.N.; Miller, S.K.; Jay, M.A.

    1994-01-01

    An active industrial silencer on a compressor engine at a Tenneco Gas station has reduced low-frequency 'rumbling' noise by 8 dB during trials while lowering backpressure about 90$. This 8 dB reduction of the piston firing frequency corresponds to a more than 80% decrease in emitted acoustic power. The silencing unit, installed on one of six engines at the station near Eden, N.Y., continues in operation. Based on the results, the manufacturer is identifying additional compressor sites for further tests. This paper reviews this project

  11. Analysis of Millstone Unit 1 system failure and maintenance data

    International Nuclear Information System (INIS)

    Bickel, J.H.; Beveridge, R.L.; Jain, N.K.; Owens, D.B.; Radder, J.A.

    1985-01-01

    As a result of a task force plan developed four years ago at Northeast Utilities, plant-specific probabilistic safety analysis models are being developed for all Northeast Utilities operating nuclear plants. An essential feature of these models is their reliance on plant-specific reliability information to the maximum extent possible. This assures that future design efforts and decisions on backfitting or procedure changes are made with full knowledge of existing plant reliability. The use of plant-specific reliability data assures that the impacts of problem components are given appropriate attention and that proper credit is given for those components, which because of plant-specific maintenance practices, have exhibited better than industry average performance. A case study of a portion of the Millstone-1 cooling system demonstrates differing results obtained by fault tree analysis and a reliability analysis using plant-specific failure data. When risk assessment techniques are being applied in resource allocation, usage of plant data clearly becomes essential for sound decision making

  12. Assessment of corrosion failure in copper tube of refrigerator unit

    International Nuclear Information System (INIS)

    Mohd Harun; Hafizal Yazid; Zaiton Selamat; Mohd Shariff Sattar; Muhamamd Jalil

    2007-01-01

    The copper tubes of the refrigerator unit have been coated with red and white color paints. According to the date of purchase and complaint recorded, the tube leaked after operation about one year. It was observed that the tubes became black and green in color at U-bend of the tube. No corrosion occurred on the internal surface of the tube. The leaking started at outer surface of the tube. The leaking started at outer surface and propagated to the internal surface of the tubes. The leaking damage was caused by corrosive species either from atmospheric corrosion or the paint contained chloride and sulfur elements. The corrosive species of sulfur and chlorine were a main factor in pitting corrosion. (author)

  13. Oil-Free Compressor

    Science.gov (United States)

    Fitzjerrell, D. G.; Belver, T. L.; Moore, H. E.

    1986-01-01

    Compressor pistons moved by eccentric shaft need no lubricants. Compressor has shaft, middle section is eccentric in relation to end sections. Driven by brushless dc motor, shaft turns inner races of set of four cam bearings. Outer cam-bearing races in turn actuate four pistons spaced equally apart, around and along shaft. Each outer bearing race held in position by pressure exerted on it by piston. Because no frictional motion between piston and outer bearing race, lubricant between them unnecessary. Cam bearings themselves contain potted internal lubricant. Originally proposed for use in space, new compressor for refrigerators or freezers does not depend on pool of oil for lubricating its pistons. Operated in any orientation.

  14. Electrochemical Hydrogen Compressor

    Energy Technology Data Exchange (ETDEWEB)

    Lipp, Ludwig [FuelCell Energy, Inc., Torrington, CT (United States)

    2016-01-21

    Conventional compressors have not been able to meet DOE targets for hydrogen refueling stations. They suffer from high capital cost, poor reliability and pose a risk of fuel contamination from lubricant oils. This project has significantly advanced the development of solid state hydrogen compressor technology for multiple applications. The project has achieved all of its major objectives. It has demonstrated capability of Electrochemical Hydrogen Compression (EHC) technology to potentially meet the DOE targets for small compressors for refueling sites. It has quantified EHC cell performance and durability, including single stage hydrogen compression from near-atmospheric pressure to 12,800 psi and operation of EHC for more than 22,000 hours. Capital cost of EHC was reduced by 60%, enabling a path to meeting the DOE cost targets for hydrogen compression, storage and delivery ($2.00-2.15/gge by 2020).

  15. Modal characteristics and fatigue strength of compressor blades

    International Nuclear Information System (INIS)

    Kim, Kyung Kook; Lee, Young Shin

    2014-01-01

    High-cycle fatigue (HCF) has been identified as one of the primary causes of gas turbine engine failure. The modal characteristics and endurance strength of a 5 MW gas turbine engine blade developed by Doosan Heavy Industries and Construction Co., Ltd. in HCF fracture were verified through analysis and tests to determine the reliability of the compressor blade. A compressor blade design procedure that considers HCF life was performed in the following order: airfoil and blade profile design, modal analysis, stress distribution test, stress endurance limit test, and fatigue life verification. This study analyzed the Campbell diagram and estimated resonance risk on the basis of the natural frequency analysis and modal test of the compressor blade to guarantee safe and operational reliability. In addition, the maximum stress point of the compressor blade was determined through stress distribution analysis and test. The bonding point of the strain gage was determined by using fatigue test. Stress endurance limit test was performed based on the results of these tests. This research compared and verified the modal characteristics and endurance strengths of the compressor blades to prevent HCF fracture, which is among the major causes of gas turbine engine damage. A fatigue life design procedure of compressor blades was established. The 5 MW class gas turbine compressor blade is well designed in terms of resonance stability and fatigue endurance limit.

  16. Modal characteristics and fatigue strength of compressor blades

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Kook [Doosan Heavy Industries and Construction, Changwon (Korea, Republic of); Lee, Young Shin [Chungnam National University, Daejeon (Korea, Republic of)

    2014-04-15

    High-cycle fatigue (HCF) has been identified as one of the primary causes of gas turbine engine failure. The modal characteristics and endurance strength of a 5 MW gas turbine engine blade developed by Doosan Heavy Industries and Construction Co., Ltd. in HCF fracture were verified through analysis and tests to determine the reliability of the compressor blade. A compressor blade design procedure that considers HCF life was performed in the following order: airfoil and blade profile design, modal analysis, stress distribution test, stress endurance limit test, and fatigue life verification. This study analyzed the Campbell diagram and estimated resonance risk on the basis of the natural frequency analysis and modal test of the compressor blade to guarantee safe and operational reliability. In addition, the maximum stress point of the compressor blade was determined through stress distribution analysis and test. The bonding point of the strain gage was determined by using fatigue test. Stress endurance limit test was performed based on the results of these tests. This research compared and verified the modal characteristics and endurance strengths of the compressor blades to prevent HCF fracture, which is among the major causes of gas turbine engine damage. A fatigue life design procedure of compressor blades was established. The 5 MW class gas turbine compressor blade is well designed in terms of resonance stability and fatigue endurance limit.

  17. Fuel failure at the Laguna Verde unit 1- during Cycle 4

    International Nuclear Information System (INIS)

    Espinosa Vega, Juan Manuel

    1996-01-01

    The present work describes the event occurred at the Laguna Verde nuclear power plants Unit 1 during its fourth cycle ensembles; the first failure, by means of a test of power suppression, and the second one, during the sipping accomplished in the four refuelling of the unit. Also it describes the re-evaluation of the event accomplished by the licenser, the manufacturer and the Mexican agency

  18. Heart failure services in the United Kingdom: rethinking the machine bureaucracy.

    Science.gov (United States)

    Hawkins, Nathaniel M; Wright, David J; Capewell, Simon

    2013-01-20

    Poor outcomes and poor uptake of evidence based therapies persist for patients with heart failure in the United Kingdom. We offer a strategic analysis of services, defining the context, organization and objectives of the service, before focusing on implementation and performance. Critical flaws in past service development and performance are apparent, a consequence of failed performance management, policy and political initiative. The barriers to change and potential solutions are common to many health care systems. Integration, information, financing, incentives, innovation and values: all must be challenged and improved if heart failure services are to succeed. Modern healthcare requires open adaptive systems, continually learning and improving. The system also needs controls. Performance indicators should be simple, clinically relevant, and outcome focused. Heart failure presents one of the greatest opportunities to improve symptoms and survival with existing technology. To do so, heart failure services require radical reorganization. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  19. RF Energy Compressor

    International Nuclear Information System (INIS)

    Farkas, Z.D.

    1980-02-01

    The RF Energy Compressor, REC described here, transforms cw rf into periodic pulses using an energy storage cavity, ESC, whose charging is controlled by 180 0 bi-phase modulation, PSK, and external Q switching, βs. Compression efficiency, C/sub e/, of 100% can be approached at any compression factor C/sub f/

  20. A helium regenerative compressor

    International Nuclear Information System (INIS)

    Swift, W.L.; Nutt, W.E.; Sixsmith, H.

    1994-01-01

    This paper discusses the design and performance of a regenerative compressor that was developed primarily for use in cryogenic helium systems. The objectives for the development were to achieve acceptable efficiency in the machine using conventional motor and bearing technology while reducing the complexity of the system required to control contamination from the lubricants. A single stage compressor was built and tested. The compressor incorporates aerodynamically shaped blades on a 218 mm (8.6 inches) diameter impeller to achieve high efficiency. A gas-buffered non-contact shaft seal is used to oppose the diffusion of lubricant from the motor bearings into the cryogenic circuit. Since it is a rotating machine, the flow is continuous and steady, and the machine is very quiet. During performance testing with helium, the single stage machine has demonstrated a pressure ratio of 1.5 at a flow rate of 12 g/s with measured isothermal efficiencies in excess of 30%. This performance compares favorably with efficiencies generally achieved in oil flooded screw compressors

  1. ACUTE RENAL FAILURE IN THE NEWBORNS HOSPITALIZED AT THE INTENSIVE CARE UNIT, UNIVERSITY CLINICAL CENTRE TUZLA

    Directory of Open Access Journals (Sweden)

    Zulić Evlijana

    2015-03-01

    Full Text Available Introduction: Reasons for acute renal failure in hospitalized infants were sepsis, hypovolemia, asphyxia, respiratory distress syndrome, surgical interventions and congenital heart defects. The aim of this study was to determine the frequency and and main etiologies, and early outcome of neonatal acute renal failure. Materials and Methods: At Intensive Care Unit, Clinical Center Tuzla, from 15. 01. 2013 to 15. 01. 2015 in 21 newborn was diagnosed renal failure, based on the amount of excreted urine and serum creatinine. Results: The prevalence of renal failure was 6.84%, with a higher incidence of female. 33.3% of infants were term neonates. Oliguria was diagnosed in 71.4% of newborns. Sepsis was the most common predisposing factor for the development of renal failure, associated with high mortality. Other causes of renal failure were perinatal hypoxia, RDS, surgical interventions and congenital heart defects. There was a positive correlation between the gestational age of the newborn and serum creatinine. Discussion: Early prevention of risk factors with rapid diagnosis and effective treatment, can affect further outcome of acute renal failure in infants.

  2. Developing a Model for Identifying Students at Risk of Failure in a First Year Accounting Unit

    Science.gov (United States)

    Smith, Malcolm; Therry, Len; Whale, Jacqui

    2012-01-01

    This paper reports on the process involved in attempting to build a predictive model capable of identifying students at risk of failure in a first year accounting unit in an Australian university. Identifying attributes that contribute to students being at risk can lead to the development of appropriate intervention strategies and support…

  3. Commissioning experience of BHEL compressors at HWP, Manuguru (Paper No. 5.1)

    International Nuclear Information System (INIS)

    Joshi, P.V.; Venugopal, M.

    1992-01-01

    Five numbers of gas booster compressors forming heart of each system of exchange units of HWP (Manuguru) are used to make up the pressure loss in circulating the H 2 S through the exchange unit towers. For X.U.-I, these machines are designed and supplied by M/s BHEL, Hyderabad. This paper highlights the commissioning activities and the problems faced during the commissioning such as seal oil flow into the lube oil system, excessive HP oil flow rate, disengagement and failure of the rubber bladders of the seal oil accumulators, excessive failure of annunciator cards of the local panel of the boosters and the problems faced during assembly and disassembly. (author). 2 figs

  4. Modelica-based modeling and simulation of a twin screw compressor for heat pump applications

    International Nuclear Information System (INIS)

    Chamoun, Marwan; Rulliere, Romuald; Haberschill, Philippe; Peureux, Jean-Louis

    2013-01-01

    A new twin screw compressor has been developed by SRM (Svenska Rotor Maskiner) for use in a new high temperature heat pump using water as refrigerant. This article presents a mathematical model of the thermodynamic process of compression in twin screw compressors. Using a special discretization method, a transient twin screw compressor model has been developed using Modelica in order to study the dry compression cycle of this machine at high temperature levels. The pressure and enthalpy evolution in the control volumes of the model are calculated as a function of the rotational angle of the male rotor using energy and continuity equations. In addition, associated processes encountered in real machines such as variable fluid leakages, water injection and heat losses are modeled and implemented in the main compressor model. A comparison is performed using the model developed, demonstrating the behavior of the compressor and the evolution of its different parameters in different configurations with and without water injection. This comparison shows the need for water injection to avoid compressor failure and improve its efficiency. -- Highlights: • Difficulties related to the compressor limit the development of a high temperature heat pump using water as refrigerant. • A new water vapor double screw compressor has been developed to overcome compression problems. • A dynamic model of this compressor has been developed and simulated using Modelica. • The behavior of the compressor has been identified all along the compression cycle and efficiencies have been calculated

  5. Failure mode and effect analysis: improving intensive care unit risk management processes.

    Science.gov (United States)

    Askari, Roohollah; Shafii, Milad; Rafiei, Sima; Abolhassani, Mohammad Sadegh; Salarikhah, Elaheh

    2017-04-18

    Purpose Failure modes and effects analysis (FMEA) is a practical tool to evaluate risks, discover failures in a proactive manner and propose corrective actions to reduce or eliminate potential risks. The purpose of this paper is to apply FMEA technique to examine the hazards associated with the process of service delivery in intensive care unit (ICU) of a tertiary hospital in Yazd, Iran. Design/methodology/approach This was a before-after study conducted between March 2013 and December 2014. By forming a FMEA team, all potential hazards associated with ICU services - their frequency and severity - were identified. Then risk priority number was calculated for each activity as an indicator representing high priority areas that need special attention and resource allocation. Findings Eight failure modes with highest priority scores including endotracheal tube defect, wrong placement of endotracheal tube, EVD interface, aspiration failure during suctioning, chest tube failure, tissue injury and deep vein thrombosis were selected for improvement. Findings affirmed that improvement strategies were generally satisfying and significantly decreased total failures. Practical implications Application of FMEA in ICUs proved to be effective in proactively decreasing the risk of failures and corrected the control measures up to acceptable levels in all eight areas of function. Originality/value Using a prospective risk assessment approach, such as FMEA, could be beneficial in dealing with potential failures through proposing preventive actions in a proactive manner. The method could be used as a tool for healthcare continuous quality improvement so that the method identifies both systemic and human errors, and offers practical advice to deal effectively with them.

  6. Fairchild 7B compressor model

    International Nuclear Information System (INIS)

    Foster, R.E.; Neely, R.S.

    1987-01-01

    The Fairchild 7B centrifugal compressor used in the X-326 isotopic ''top'' cascade at the Portsmouth Gaseous Diffusion Plant has been modeled using a proprietary computer code called COMPAL by Concepts E.T.I., Inc. of Norwich, VT. The 7B compressor is described and some results of the modeling calculations are presented. Performance characteristics curves (PR/sub b/vs. flow and PR/sub a/) are included for UF 6 gas for two compressor inlet temperatures

  7. Common-cause failure analysis of McGuire Unit 2 auxiliary feedwater system

    International Nuclear Information System (INIS)

    Rasmuson, D.M.; Shepherd, J.C.; Fowler, R.D.; Summitt, R.L.; Logan, B.W.

    1982-01-01

    A powerful method for qualitative common cause failure analysis (CCFA) of nuclear power plant systems was developed by EG and G Idaho at the Idaho National Engineering Laboratory. As a cooperative project to demonstrate and evaluate the usefulness of the method, the Duke Power Company agreed to allow a CCFA of the auxiliary feedwater system (AFWS) in their McGuire Nuclear Station Unit 2. The results of the CCFA are the subject of this discussion

  8. Non-traditional vibration mitigation methods for reciprocating compressor system

    NARCIS (Netherlands)

    Eijk, A.; Lange, T.J. de; Vreugd, J. de; Slis, E.J.P.

    2016-01-01

    Reciprocating compressors generate vibrations caused by pulsation-induced forces, mechanical (unbalanced) free forces and moments, crosshead guide forces and cylinder stretch forces. The traditional way of mitigating the vibration and cyclic stress levels to avoid fatigue failure of parts of the

  9. Failure mechanisms of additively manufactured porous biomaterials: Effects of porosity and type of unit cell.

    Science.gov (United States)

    Kadkhodapour, J; Montazerian, H; Darabi, A Ch; Anaraki, A P; Ahmadi, S M; Zadpoor, A A; Schmauder, S

    2015-10-01

    Since the advent of additive manufacturing techniques, regular porous biomaterials have emerged as promising candidates for tissue engineering scaffolds owing to their controllable pore architecture and feasibility in producing scaffolds from a variety of biomaterials. The architecture of scaffolds could be designed to achieve similar mechanical properties as in the host bone tissue, thereby avoiding issues such as stress shielding in bone replacement procedure. In this paper, the deformation and failure mechanisms of porous titanium (Ti6Al4V) biomaterials manufactured by selective laser melting from two different types of repeating unit cells, namely cubic and diamond lattice structures, with four different porosities are studied. The mechanical behavior of the above-mentioned porous biomaterials was studied using finite element models. The computational results were compared with the experimental findings from a previous study of ours. The Johnson-Cook plasticity and damage model was implemented in the finite element models to simulate the failure of the additively manufactured scaffolds under compression. The computationally predicted stress-strain curves were compared with the experimental ones. The computational models incorporating the Johnson-Cook damage model could predict the plateau stress and maximum stress at the first peak with less than 18% error. Moreover, the computationally predicted deformation modes were in good agreement with the results of scaling law analysis. A layer-by-layer failure mechanism was found for the stretch-dominated structures, i.e. structures made from the cubic unit cell, while the failure of the bending-dominated structures, i.e. structures made from the diamond unit cells, was accompanied by the shearing bands of 45°. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Cooled-Spool Piston Compressor

    Science.gov (United States)

    Morris, Brian G.

    1994-01-01

    Proposed cooled-spool piston compressor driven by hydraulic power and features internal cooling of piston by flowing hydraulic fluid to limit temperature of compressed gas. Provides sufficient cooling for higher compression ratios or reactive gases. Unlike conventional piston compressors, all parts of compressed gas lie at all times within relatively short distance of cooled surface so that gas cooled more effectively.

  11. Low-Vibration Oscillating Compressor

    Science.gov (United States)

    Studer, P. A.

    1984-01-01

    Oscillating compressor momentum compensated: produces little vibration in its supporting structure. Compressure requires no lubrication and virtually free of wear. Compresses working fluids such as helium, nitrogen or chlorfluorocarbons for Stirling-cycle refrigeration or other purposes. Compressor includes two mutually opposed ferromagnetic pistons of same shape and mass. Electromagnetic flux links both pistons, causing magnetic attraction between them.

  12. NASA low speed centrifugal compressor

    Science.gov (United States)

    Hathaway, Michael D.

    1990-01-01

    The flow characteristics of a low speed centrifugal compressor were examined at NASA Lewis Research Center to improve understanding of the flow in centrifugal compressors, to provide models of various flow phenomena, and to acquire benchmark data for three dimensional viscous flow code validation. The paper describes the objectives, test facilities' instrumentation, and experiment preliminary comparisons.

  13. Centrifugal-reciprocating compressor

    Science.gov (United States)

    Higa, W. H. (Inventor)

    1984-01-01

    A centrifugal compressor is described which includes at least one pair of cylinders arranged in coaxial alignment and supported for angular displacement about a common axis of rotation normally disecting a common longitudinal axis of symmetry for the cylinders. The cylinders are characterized by ported closures located at the mutually remote ends thereof through which the cylinders are charged and discharged, and a pair of piston heads seated within the cylinders and supported for floating displacement in compressive strokes in response to unidirectional angular displacement imparted to the cylinders.

  14. Modeling of scroll compressors - Improvements

    Energy Technology Data Exchange (ETDEWEB)

    Duprez, Marie-Eve; Dumont, Eric; Frere, Marc [Thermodynamics Department, Universite de Mons - Faculte Polytechnique, 31 bd Dolez, 7000 Mons (Belgium)

    2010-06-15

    This paper presents an improvement of the scroll compressors model previously published by. This improved model allows the calculation of refrigerant mass flow rate, power consumption and heat flow rate that would be released at the condenser of a heat pump equipped with the compressor, from the knowledge of operating conditions and parameters. Both basic and improved models have been tested on scroll compressors using different refrigerants. This study has been limited to compressors with a maximum electrical power of 14 kW and for evaporation temperatures ranging from -40 to 15 C and condensation temperatures from 10 to 75 C. The average discrepancies on mass flow rate, power consumption and heat flow rate are respectively 0.50%, 0.93% and 3.49%. Using a global parameter determination (based on several refrigerants data), this model can predict the behavior of a compressor with another fluid for which no manufacturer data are available. (author)

  15. The constant failure rate model for fault tree evaluation as a tool for unit protection reliability assessment

    International Nuclear Information System (INIS)

    Vichev, S.; Bogdanov, D.

    2000-01-01

    The purpose of this paper is to introduce the fault tree analysis method as a tool for unit protection reliability estimation. The constant failure rate model applies for making reliability assessment, and especially availability assessment. For that purpose an example for unit primary equipment structure and fault tree example for simplified unit protection system is presented (author)

  16. Comprehensive 3D-elastohydrodynamic simulation of hermetic compressor crank drive

    Science.gov (United States)

    Posch, S.; Hopfgartner, J.; Berger, E.; Zuber, B.; Almbauer, R.; Schöllauf, P.

    2017-08-01

    Mechanical, electrical and thermodynamic losses form the major loss mechanisms of hermetic compressors for refrigeration application. The present work deals with the investigation of the mechanical losses of a hermetic compressor crank drive. Focus is on 3d-elastohydrodynamic (EHD) modelling of the journal bearings, piston-liner contact and piston secondary motion in combination with multi-body and structural dynamics of the crank drive elements. A detailed description of the model development within the commercial software AVL EXCITE Power Unit is given in the work. The model is used to create a comprehensive analysis of the mechanical losses of a hermetic compressor. Further on, a parametric study concerning oil viscosity and compressor speed is carried out which shows the possibilities of the usage of the model in the development process of hermetic compressors for refrigeration application. Additionally, the usage of the results in an overall thermal network for the determination of the thermal compressor behaviour is discussed.

  17. Deaths Due to Accidental Air Conditioner Compressor Explosion: A Case Series.

    Science.gov (United States)

    Behera, Chittaranjan; Bodwal, Jatin; Sikary, Asit K; Chauhan, Mohit Singh; Bijarnia, Manjul

    2017-01-01

    In an air-conditioning system, the compressor is a large electric pump that pressurizes the refrigerant gas as part of the process of turning it back into a liquid. The explosion of an air conditioner (AC) compressor is an uncommon event, and immediate death resulted from the blast effect is not reported in forensic literature. We report three such cases in which young AC mechanics were killed on the spot due to compressor blast, while repairing the domestic split AC unit. The autopsy findings, the circumstances leading to the explosion of the compressor, are discussed in this study. © 2016 American Academy of Forensic Sciences.

  18. The design and development of an oil-free compressor for Spacelab Refrigerator/Freezer

    Science.gov (United States)

    Hye, A.

    1984-01-01

    Design features and test results of an oil-free compressor developed for Spacelab Mission-4 Refrigerator/Freezer are detailed. The compressor has four identical pistons activated by a common eccentric shaft, operated by a brushless dc motor at 1300 rpm. The stroke of each piston is 0.28 cm, with the piston ends connected to the shaft by means of sealed needle bearings, eliminating the ned for oil. The mass flow rates produced by the compressor are by over 100 percent higher compared to the original Amfridge unit. Test results show that the compressor can meet the Spacelab refrigerator/freezer requirements.

  19. New Compressor Added to Glenn's 450- psig Combustion Air System

    Science.gov (United States)

    Swan, Jeffrey A.

    2000-01-01

    In September 1999, the Central Process Systems Engineering Branch and the Maintenance and the Central Process Systems Operations Branch, released for service a new high pressure compressor to supplement the 450-psig Combustion Air System at the NASA Glenn Research Center at Lewis Field. The new compressor, designated C-18, is located in Glenn s Central Air Equipment Building and is remotely operated from the Central Control Building. C-18 can provide 40 pounds per second (pps) of airflow at pressure to our research customers. This capability augments our existing system capacity (compressors C 4 at 38 pps and C-5 at 32 pps), which is generated from Glenn's Engine Research Building. The C-18 compressor was originally part of Glenn's 21-Inch Hypersonic Tunnel, which was transferred from the Jet Propulsion Laboratory to Glenn in the mid-1980's. With the investment of construction of facilities funding, the compressor was modified, new mechanical and electrical support equipment were purchased, and the unit was installed in the basement of the Central Air Equipment Building. After several weeks of checkout and troubleshooting, the new compressor was ready for long-term, reliable operations. With a total of 110 pps in airflow now available, Glenn is well positioned to support the high-pressure air test requirements of our research customers.

  20. Centrifugal Compressor Aeroelastic Analysis Code

    Science.gov (United States)

    Keith, Theo G., Jr.; Srivastava, Rakesh

    2002-01-01

    Centrifugal compressors are very widely used in the turbomachine industry where low mass flow rates are required. Gas turbine engines for tanks, rotorcraft and small jets rely extensively on centrifugal compressors for rugged and compact design. These compressors experience problems related with unsteadiness of flowfields, such as stall flutter, separation at the trailing edge over diffuser guide vanes, tip vortex unsteadiness, etc., leading to rotating stall and surge. Considerable interest exists in small gas turbine engine manufacturers to understand and eventually eliminate the problems related to centrifugal compressors. The geometric complexity of centrifugal compressor blades and the twisting of the blade passages makes the linear methods inapplicable. Advanced computational fluid dynamics (CFD) methods are needed for accurate unsteady aerodynamic and aeroelastic analysis of centrifugal compressors. Most of the current day industrial turbomachines and small aircraft engines are designed with a centrifugal compressor. With such a large customer base and NASA Glenn Research Center being, the lead center for turbomachines, it is important that adequate emphasis be placed on this area as well. Currently, this activity is not supported under any project at NASA Glenn.

  1. Characterization of Multiflux Axial Compressors

    International Nuclear Information System (INIS)

    Brasnarof, Daniel; Kyung Kyu-Hyung; Rivarola, Martin; Gonzalez Jose; Florido, Pablo; Orellano, Pablo; Bergallo, Juan

    2003-01-01

    In the present work the results of analytical models of performance are compared with experimental data acquired in the multi flux axial compressor test facility, built in The Pilcaniyeu Technological Complex for the SIGMA project.We describe the experimental circuit and the data of the dispersion inside the axial compressor obtained using a tracer gas through one of the annular inlets.The attained results can be used to validate the design code for the multi flux axial compressors and SIGMA industrial plant

  2. Compressor performance aerodynamics for the user

    CERN Document Server

    Gresh, Theodore

    2001-01-01

    Compressor Performance is a reference book and CD-ROM for compressor design engineers and compressor maintenance engineers, as well as engineering students. The book covers the full spectrum of information needed for an individual to select, operate, test and maintain axial or centrifugal compressors. It includes basic aerodynamic theory to provide the user with the ""how's"" and ""why's"" of compressor design. Maintenance engineers will especially appreciate the troubleshooting guidelines offered. Includes many example problems and reference data such as gas propert

  3. A review of linear compressors for refrigeration

    OpenAIRE

    Liang, Kun

    2017-01-01

    Linear compressor has no crank mechanism compared with conventional reciprocating compressor. This allows higher efficiency, oil-free operation, lower cost and smaller size when linear compressors are used for vapour compression refrigeration (VCR) system. Typically, a linear compressor consists of a linear motor (connected to a piston) and suspension springs, operated at resonant frequency. This paper presents a review of linear compressors for refrigeration system. Different designs and mod...

  4. Bayesian framework for prediction of future number of failures from a single group of units in the field

    International Nuclear Information System (INIS)

    Ebrahimi, Nader

    2009-01-01

    This paper considers prediction of unknown number of failures in a future inspection of a group of in-service units based on number of failures observed from an earlier inspection. We develop a flexible Bayesian model and calculate Bayesian estimator for this unknown number and other quantities of interest. The paper also includes an illustration of our method in an example about heat exchanger. A main advantage of our approach is in its nonparametric nature. By nonparametric here we simply mean that no assumption is required about the failure time distribution of a unit

  5. Free piston inertia compressor

    Science.gov (United States)

    Richards, W.D.C.; Bilodeau, D.; Marusak, T.; Dutram, L. Jr.; Brady, J.

    A free piston inertia compressor comprises a piston assembly including a connecting rod having pistons on both ends, the cylinder being split into two substantially identical portions by a seal through which the connecting rod passes. Vents in the cylinder wall are provided near the seal to permit gas to escape the cylinder until the piston covers the vent whereupon the remaining gas in the cylinder functions as a gas spring and cushions the piston against impact on the seal. The connecting rod has a central portion of relatively small diameter providing free play of the connecting rod through the seal and end portions of relatively large diameter providing a limited tolerance between the connecting rod and the seal. Finally, the seal comprises a seal ring assembly consisting of a dampener plate, a free floating seal at the center of the dampener plate and a seal retainer plate in one face of the dampener plate.

  6. Dual capacity reciprocating compressor

    Science.gov (United States)

    Wolfe, Robert W.

    1984-01-01

    A multi-cylinder compressor 10 particularly useful in connection with northern climate heat pumps and in which different capacities are available in accordance with reversing motor 16 rotation is provided with an eccentric cam 38 on a crank pin 34 under a fraction of the connecting rods, and arranged for rotation upon the crank pin between opposite positions 180.degree. apart so that with cam rotation on the crank pin such that the crank throw is at its normal maximum value all pistons pump at full capacity, and with rotation of the crank shaft in the opposite direction the cam moves to a circumferential position on the crank pin such that the overall crank throw is zero. Pistons 24 whose connecting rods 30 ride on a crank pin 36 without a cam pump their normal rate with either crank rotational direction. Thus a small clearance volume is provided for any piston that moves when in either capacity mode of operation.

  7. A cryogenic axial-centrifugal compressor for superfluid helium refrigeration

    CERN Document Server

    Decker, L; Schustr, P; Vins, M; Brunovsky, I; Lebrun, P; Tavian, L

    1997-01-01

    CERN's new project, the Large Hadron Collider (LHC), will use superfluid helium as coolant for its high-field superconducting magnets and therefore require large capacity refrigeration at 1.8 K. This may only be achieved by subatmospheric compression of gaseous helium at cryogenic temperature. To stimulate development of this technology, CERN has procured from industry prototype Cold Compressor Units (CCU). This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating under low-pressure helium at ambient temperature. The machine has been commissioned and is now in operation. After describing basic constructional features of the compressor, we report on measured performance.

  8. A Case of Biotinidase Deficiency in an Adult with Respiratory Failure in the Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Zerrin Demirtürk

    2016-10-01

    Full Text Available Background: Biotinidase deficiency (BD is a rare, inherited autosomal recessive disorder that is treatable within childhood. We present a patient with pneumonia and respiratory acidosis who was not diagnosed with any systemic disorders; the patient was finally diagnosed as BD. Case Report: A thirty-year-old woman was admitted to the emergency department with respiratory failure that had persisted for a few days and progressively weakening over the previous six months. Then, the patient was admitted to the intensive care unit with marked respiratory acidosis, respiratory failure and alterations in consciousness. At the follow-up, the patient was not diagnosed with a systematic disorder. Rather, the patient’s historical clinical findings suggested a metabolic disorder. Finally, the patient was diagnosed with biotinidase deficiency. Conclusion: Even though biotinidase deficiency is not frequently seen in the intensive care unit, metabolic syndromes such as biotinidase deficiency should be considered. Patients should be evaluated holistically with attention to medical history, family history and clinical findings.

  9. Low emissions system featured on compressor drive

    International Nuclear Information System (INIS)

    Curtis, T.

    1995-01-01

    A high speed power turbine is offered as an option with direct drive capability for pipeline compressors and other high-speed applications. As developed, it features ease of maintenance with rotor and nozzle assembly in a single cartridge to allow quick change-out or replacement of parts on site. The new compressor drive builds extensively on proven technology and is expected to provide lower installed and life-cycle costs per unit horsepower than previous units. During its development stages, M ampersand IE preformed cost and risk assessment of several design configurations and concluded that a derivative approach based on the standard unit was an optimal solution in the 39,000 shp range. A two-shaft gas turbine is expected to be applied in the industrial and commercial marine markets, including 50- and 60-Hertz power generation applications, pipeline compression, gas injection, and fast ferry commercial marine uses. Emissions controls for the system will include water or steam injection using a standard combustor or M and IE's DLE combustion system

  10. Concept and methodology for evaluating core damage frequency considering failure correlation at multi units and sites and its application

    Energy Technology Data Exchange (ETDEWEB)

    Ebisawa, K.; Teragaki, T.; Nomura, S. [Former Incorporated Administrative Agency, Japan Nuclear Safety Organization (Japan); Abe, H., E-mail: Hiroshi_abe@nsr.go.jp [Former Incorporated Administrative Agency, Japan Nuclear Safety Organization (Japan); Shigemori, M.; Shimomoto, M. [Mizuho Information & Research Institute, 2-3, Kanda-Nishikicho, Chiyoda-ku, Tokyo (Japan)

    2015-07-15

    Highlights: • We develop a method to evaluate CDF considering failure correlation at multi units. • We develop a procedure to evaluate correlation coefficient between multi components. • We evaluate CDF at two different BWR units using correlation coefficients. • We confirm the validity of method and correlation coefficient through the evaluation. - Abstract: The Tohoku earthquake (Mw9.0) occurred on March 11, 2011 and caused a large tsunami. The Fukushima Daiichi Nuclear Power Plant with six units were overwhelmed by the tsunami and core damage occurred. Authors proposed the concept and method for evaluating core damage frequency (CDF) considering failure correlation at the multi units and sites. Based on the above method, one of authors developed the procedure for evaluating the failure correlation coefficient and response correlation coefficient between the multi components under the strong seismic motion. These method and failure correlation coefficients were applied to two different BWR units and their CDF was evaluated by seismic probabilistic risk assessment technology. Through this quantitative evaluation, the validity of the method and failure correlation coefficient was confirmed.

  11. Concept and methodology for evaluating core damage frequency considering failure correlation at multi units and sites and its application

    International Nuclear Information System (INIS)

    Ebisawa, K.; Teragaki, T.; Nomura, S.; Abe, H.; Shigemori, M.; Shimomoto, M.

    2015-01-01

    Highlights: • We develop a method to evaluate CDF considering failure correlation at multi units. • We develop a procedure to evaluate correlation coefficient between multi components. • We evaluate CDF at two different BWR units using correlation coefficients. • We confirm the validity of method and correlation coefficient through the evaluation. - Abstract: The Tohoku earthquake (Mw9.0) occurred on March 11, 2011 and caused a large tsunami. The Fukushima Daiichi Nuclear Power Plant with six units were overwhelmed by the tsunami and core damage occurred. Authors proposed the concept and method for evaluating core damage frequency (CDF) considering failure correlation at the multi units and sites. Based on the above method, one of authors developed the procedure for evaluating the failure correlation coefficient and response correlation coefficient between the multi components under the strong seismic motion. These method and failure correlation coefficients were applied to two different BWR units and their CDF was evaluated by seismic probabilistic risk assessment technology. Through this quantitative evaluation, the validity of the method and failure correlation coefficient was confirmed

  12. DETECTION OF CLAMPING FORCES ON MOUNTING A CONSTRUCTION VIA NEURAL NETWORK FOR THE FINITE-ELEMENT MODEL OF COMPRESSOR-CONDENSING UNIT

    Directory of Open Access Journals (Sweden)

    S. V. Krasnovskaya

    2017-01-01

    Full Text Available The article provides a brief review of a condensing unit and problems of mathematic simulation. It examines the influence of pretension on the strain-stress state of a construction by means of finiteelement modeling. The arrangement of a set of input-output data for neural network is also considered. The article investigates a possibility to predict mounting precision via neural networks; by analogy with the above calculations it examines the option to detect clamping forces on mounting compressorcondensing unit

  13. Screening and treatment for heritable thrombophilia in pregnancy failure: inconsistencies among UK early pregnancy units.

    Science.gov (United States)

    Norrie, Gillian; Farquharson, Roy G; Greaves, Mike

    2009-01-01

    The significance of heritable thrombophilia in pregnancy failure is controversial. We surveyed all UK Early Pregnancy Units and 70% responded. The majority test routinely for heritable thrombophilias; 80%, 76% and 88% undertook at least one screening test in late miscarriage, recurrent miscarriage and placental abruption, respectively. The range of thrombophilias sought is inconsistent: testing for proteins C and S deficiency and F5 R506Q (factor V Leiden) is most prevalent. Detection of heritable thrombophilia frequently leads to administration of antithrombotics in subsequent pregnancies. Thus, thrombophilia testing and use of antithrombotics are widespread in the UK despite controversies regarding the role of heritable thrombophilia in the pathogenesis of pregnancy complications, and the lack of robust evidence for the efficacy of antithrombotic therapy.

  14. Factors associated with variations in hospital expenditures for acute heart failure in the United States.

    Science.gov (United States)

    Ziaeian, Boback; Sharma, Puza P; Yu, Tzy-Chyi; Johnson, Katherine Waltman; Fonarow, Gregg C

    2015-02-01

    Relatively little contemporary data are available that describe differences in acute heart failure (AHF) hospitalization expenditures as a function of patient and hospital characteristics, especially from a population-based investigation. This study aimed to evaluate factors associated with variations in hospital expenditures for AHF in the United States. A cross-sectional analysis using discharge data from the 2011 Nationwide Inpatient Sample, Healthcare Cost and Utilization Project, was conducted. Discharges with primary International Classification of Diseases, Ninth Revision, Clinical Modification, diagnosis codes for AHF in adults were included. Costs were estimated by converting Nationwide Inpatient Sample charge data using the Healthcare Cost and Utilization Project Cost-to-Charge Ratio File. Discharges with highest (≥80th percentile) versus lowest (≤20th percentile) costs were compared for patient characteristics, hospital characteristics, utilization of procedures, and outcomes. Of the estimated 1 million AHF hospital discharges, the mean cost estimates were $10,775 per episode. Younger age, higher percentage of obesity, atrial fibrillation, pulmonary disease, fluid/electrolyte disturbances, renal insufficiency, and greater number of cardiac/noncardiac procedures were observed in stays with highest versus lowest costs. Highest-cost discharges were more likely to be observed in urban and teaching hospitals. Highest-cost AHF discharges also had 5 times longer length of stay, were 9 times more costly, and had higher in-hospital mortality (5.6% vs 3.5%) compared with discharges with lowest costs (all P heart failure hospitalizations are costly. Expenditures vary markedly among AHF hospitalizations in the United States, with substantial differences in patient and hospital characteristics, procedures, and in-hospital outcomes among discharges with highest compared with lowest costs. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Management of hypoxaemic respiratory failure in a Respiratory High-dependency Unit.

    Science.gov (United States)

    Hukins, Craig; Wong, Mimi; Murphy, Michelle; Upham, John

    2017-07-01

    There are limited data on outcomes of hypoxaemic respiratory failure (HRF), especially in non-intensive care unit (ICU) settings. To assess outcomes in HRF (without multi-system disease and not requiring early intubation) of patients directly admitted to a Respiratory High-dependency Unit (R-HDU). This is a retrospective cohort study of HRF compared to hypercapnic respiratory failure (HCRF) in a R-HDU (2007-2011). Patient characteristics (age, gender, pre-morbid status, diagnoses) and outcomes (non-invasive ventilation (NIV) use, survival, ICU admission) were assessed. There were 1207 R-HDU admissions in 2007-2011, 205 (17%) with HRF and 495 (41%) with HCRF. The proportion with HRF increased from 12.2% in 2007 to 20.1% in 2011 (P < 0.05). HRF patients were younger, more often male and had better pre-morbid performance. Compared to HCRF, HRF was more frequently associated with lung consolidation (61% vs 15%, P < 0.001), interstitial lung disease (12% vs 1%, P < 0.001) and pulmonary hypertension (7% vs 0%, P < 0.001) and less frequently with chronic obstructive pulmonary disease (24% vs 65%, P < 0.001) and obstructive sleep apnoea (8% vs 26%, P < 0.001). Fewer patients with HRF were treated with NIV (28% vs 87%, P < 0.001), but NIV was discontinued early more often (28% vs 7%, P < 0.001). A total of 18% with HRF was transferred to ICU compared to 6% with HCRF (P = 0.06). More patients with HRF died (19.5% vs 12.3%, P = 0.02). Interstitial lung disease, consolidation, shock, malignancy and poorer pre-morbid function were associated with increased mortality. Initial R-HDU management is an effective option in selected HRF to reduce ICU demand, although mortality and clinical deterioration despite NIV are more common than in HCRF. © 2017 Royal Australasian College of Physicians.

  16. Fuel efficiency, availability and compressor station configuration

    Energy Technology Data Exchange (ETDEWEB)

    Lubomirsky, Matt; Kurz, Rainer [Solar Turbines Inc., San Diego, CA (United States); Klimov, Pavel [Intergas Central Asia, Astana (Kazakhstan)

    2009-12-19

    Compressor stations play a very important role in the success of a gas pipeline design and a careful selection of centrifugal compressors and drivers are key aspects for the success of the project. The state of the art design available today for this equipment provides overall high thermodynamic performance and consequently minimizes installed power requirements and energy usage with significant savings on operating expenses during the economic life of the project For any application of machinery in a pipeline compression station, one of the key questions to answer is the number of units to install to meet the flow requirements of the pipeline. Depending on the load profile of the pipeline, the answers may look different. Other factors to consider include the fact that gas turbines can produce a significant amount of additional power at lower ambient temperatures. So, even for constant load of the pipeline, the relative load of the driver changes. In this paper, a typical transcontinental pipeline with multiple compressor stations is evaluated. The determination of the exact hydraulic behavior of the pipeline is part of the modeling effort. The site ambient conditions, with a significant swing in ambient temperatures are considered. The issue discussed in this paper evolves around the availability that can be achieved with various configurations, based on actually achieved reliability and availability numbers. The other large impact on operating costs, fuel consumption will be discussed. Here, the choice of the number of installed units has a distinct impact on annual fuel consumption, as well as the capacity of the pipeline during various scenarios. (author)

  17. Common cause failure analysis of the rodded scram system of the Arkansas Nuclear One-Unit 1 Plant

    International Nuclear Information System (INIS)

    Montague, D.F.; Campbell, D.J.; Flanagan, G.F.

    1986-10-01

    This study demonstrates the use of a formal method for common cause failure analysis in a reliability analysis of the Arkansas Nuclear One - Unit 1 rodded scram system. The scram system failure of interest is loss of capability of the system to shut the reactor down when required. The results of this analysis support the ATWS program sponsored by the US Nuclear Regulatory Commission. The methods used in this analysis support the NRC's Risk Methods Integration and Evaluation Program (RMIEP)

  18. Failure Mode Estimation of Wolsong Unit 1 Containment Building with respect to Severe Accident Condition

    International Nuclear Information System (INIS)

    Hahm, Dae Gi; Choi, In Kil

    2009-01-01

    The containment buildings in a nuclear power plant (NPP) are final barriers against the exposure of harmful radiation materials at severe accident condition. Since the accident at Three Mile Island nuclear plant in 1979, it has become necessary to evaluate the internal pressure capacity of the containment buildings for the assessment of the safety of nuclear power plants. According to this necessity, many researchers including Yonezawa et al. and Hu and Lin analyzed the ultimate capacity of prestressed concrete containments subjected to internal pressure which can be occurred at sever accident condition. Especially in Wolsong nuclear power plant, the Unit 1 containment structures were constructed in the late 1970 to early 1980, so that the end of its service life will be reached in near future. Since that the complete decommission and reconstruction of the NPP may cause a huge expenses, an extension of the service time can be a cost-effective alternative. To extend the service time of NPP, an overall safety evaluation of the containment building under severe accident condition should be performed. In this study, we assessed the pressure capacity of Wolsong Unit 1 containment building under severe accident, and estimated the responses at all of the probable critical areas. Based on those results, we found the significant failure modes of Wolsong Unit 1 containment building with respect to the severe accident condition. On the other hand, for the aged NPP, the degradation of their structural performance must also be explained in the procedure of the internal pressure capacity evaluation. Therefore, in this study, we performed a parametric study on the degradation effects and evaluated the internal pressure capacity of Wolsong Unit 1 containment building with considering aging and degradation effects

  19. Age and admission times as predictive factors for failure of admissions to discharge-stream short-stay units.

    Science.gov (United States)

    Shetty, Amith L; Shankar Raju, Savitha Banagar; Hermiz, Arsalan; Vaghasiya, Milan; Vukasovic, Matthew

    2015-02-01

    Discharge-stream emergency short-stay units (ESSU) improve ED and hospital efficiency. Age of patients and time of hospital presentations have been shown to correlate with increasing complexity of care. We aim to determine whether an age and time cut-off could be derived to subsequently improve short-stay unit success rates. We conducted a retrospective audit on 6703 (5522 inclusions) patients admitted to our discharge-stream short-stay unit. Patients were classified as appropriate or inappropriate admissions, and deemed successful if discharged out of the unit within 24 h; and failures if they needed inpatient admission into the hospital. We calculated short-stay unit length of stay for patients in each of these groups. A 15% failure rate was deemed as acceptable key performance indicator (KPI) for our unit. There were 197 out of 4621 (4.3%, 95% CI 3.7-4.9%) patients up to the age of 70 who failed admission to ESSU compared with 67 out of 901 (7.4%, 95% CI 5.9-9.3%, P 70 years of age have higher rates of failure after admission to discharge-stream ESSU. Although in appropriately selected discharge-stream patients, no age group or time-band of presentation was associated with increased failure rate beyond the stipulated KPI. © 2014 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  20. DUSTMS-D: DISPOSAL UNIT SOURCE TERM - MULTIPLE SPECIES - DISTRIBUTED FAILURE DATA INPUT GUIDE.

    Energy Technology Data Exchange (ETDEWEB)

    SULLIVAN, T.M.

    2006-01-01

    Performance assessment of a low-level waste (LLW) disposal facility begins with an estimation of the rate at which radionuclides migrate out of the facility (i.e., the source term). The focus of this work is to develop a methodology for calculating the source term. In general, the source term is influenced by the radionuclide inventory, the wasteforms and containers used to dispose of the inventory, and the physical processes that lead to release from the facility (fluid flow, container degradation, wasteform leaching, and radionuclide transport). Many of these physical processes are influenced by the design of the disposal facility (e.g., how the engineered barriers control infiltration of water). The complexity of the problem and the absence of appropriate data prevent development of an entirely mechanistic representation of radionuclide release from a disposal facility. Typically, a number of assumptions, based on knowledge of the disposal system, are used to simplify the problem. This has been done and the resulting models have been incorporated into the computer code DUST-MS (Disposal Unit Source Term-Multiple Species). The DUST-MS computer code is designed to model water flow, container degradation, release of contaminants from the wasteform to the contacting solution and transport through the subsurface media. Water flow through the facility over time is modeled using tabular input. Container degradation models include three types of failure rates: (a) instantaneous (all containers in a control volume fail at once), (b) uniformly distributed failures (containers fail at a linear rate between a specified starting and ending time), and (c) gaussian failure rates (containers fail at a rate determined by a mean failure time, standard deviation and gaussian distribution). Wasteform release models include four release mechanisms: (a) rinse with partitioning (inventory is released instantly upon container failure subject to equilibrium partitioning (sorption) with

  1. Vibration signature analysis of compressors in the gaseous diffusion process for uranium enrichment

    International Nuclear Information System (INIS)

    Harbarger, W.B.

    1975-01-01

    Continuous operation of several thousand axial-flow and centrifugal compressors is vital to the gaseous diffusion process for uranium enrichment. Vibration signature analysis using a minicomputer-based Fast Fourier Transform Analyzer is being applied to the evaluation and surveillance of compressor performance at the Portsmouth Gaseous Diffusion Plant. Three areas of application include: (1) new blade design and prototype compressor evaluation; (2) corrective and preventive maintenance of machinery components; and (3) evaluation of machinery health. The present system is being used to monitor signals from accelerometers mounted on the load-bearing housings of 16 on-line compressors. These signals are transmitted by hard-wire to the analyzer for daily monitoring. A program for expansion of this system to monitor more than a thousand compressors and automation of the signature comparison process is planned for all three gaseous diffusion plants operated for the United States Energy Research and Development Administration. (auth)

  2. Empirical Design Considerations for Industrial Centrifugal Compressors

    Directory of Open Access Journals (Sweden)

    Cheng Xu

    2012-01-01

    Full Text Available Computational Fluid Dynamics (CFD has been extensively used in centrifugal compressor design. CFD provides further optimisation opportunities for the compressor design rather than designing the centrifugal compressor. The experience-based design process still plays an important role for new compressor developments. The wide variety of design subjects represents a very complex design world for centrifugal compressor designers. Therefore, some basic information for centrifugal design is still very important. The impeller is the key part of the centrifugal stage. Designing a highly efficiency impeller with a wide operation range can ensure overall stage design success. This paper provides some empirical information for designing industrial centrifugal compressors with a focus on the impeller. A ported shroud compressor basic design guideline is also discussed for improving the compressor range.

  3. Tests of cold helium compressors at Fermilab

    International Nuclear Information System (INIS)

    Peterson, T.J.; Fuerst, J.D.

    1987-10-01

    Fermilab has tested two cold helium compressors for possible installation in the satellite refrigerator buildings of the Tevatron cryogenic system. Operating conditions required to obtain an overall Tevatron energy upgrade from 900 to 1000 GeV are (for each of 24 machines): 52 g/s mass flow rate, 0.7 atm inlet pressure, 1.4 atm exhaust pressure. Acceptable efficiency is in the 60% range. Both Creare, Inc., and Cryogenic Consultants, Inc. (CCI), have supplied units for evaluation. The Creare machine is a high speed centrifugal pump/compressor which yielded 60% adiabatic efficiency (including an approximately 20 watt heat leak) with a 1.0 atm inlet pressure and 55 g/s flow rate. Certain mechanical difficulties were present, chiefly the device's inability to withstand two-phase flow. CCI supplied a reciprocating unit which, after initial testing and modification, achieved 59% efficiency with an approximate 35 watt heat leak at a 0.7 atm inlet pressure and 48 g/s flow rate. Although the device lacks the smooth, quiet operating characteristics of a turbomachine, it has endured mechanically throughout testing and is entirely insensitive to two-phase flow

  4. Development of a linear compressor for compact 2 K Gifford- McMahon cryocoolers

    International Nuclear Information System (INIS)

    Hiratsuka, Y

    2015-01-01

    Recently, a new, compact Gifford-McMahon (GM) cryocooler for cooling superconducting single photon detectors (SSPD) has been developed at Sumitomo Heavy Industries, Ltd. (SHI) [1, 2]. The objective is to reduce the total height of the expander by 33% relative to the existing RDK-101 GM expander and to reduce the total volume of the compressor unit by 50% relative to the existing CNA-11 compressor. In addition, considering the targeted cooling application, we set the design temperature targets of the first and the second stages to 1 W and 20 mW of heat load at 60 K and 2.3 K, respectively. Although optimization of the internal components is one way to miniaturize the volume of the compressor unit, major design changes are required because the volume of the adsorber and the oil separator is almost the same as the volume of the compressor capsule. Thus, one approach is to develop a non-lubricated compressor, such as a valved linear compressor. An experimental unit of a valved linear compressor was designed and built, and preliminary experiments were conducted. Under no-load condition, a low temperature of 2.19 K has been achieved. With 1 W and 14 mW heat load, the temperature is 48 K at the first stage and 2.3 K at the second stage, with an input power of about 1.2 KW. The detailed experimental results will be discussed in this paper. (paper)

  5. 原料气压缩机组检修技术总结%Technical summary of maintenance of air compressor unit

    Institute of Scientific and Technical Information of China (English)

    罗伟雄; 符和穗

    2015-01-01

    the raw material pressure reducing unit is the synthetic equipment of 800000 t chemical fertilizer plant in Hainan base of CNOOC chemical Limited by Share Ltd.Since the commissioning of the equipment maintenance tasks have been outside the Commission other chemical inspection unit is responsible for the overhaul of the equipment in 2015 the first time by the company to bear,I encountered in the process of maintenance problems and treatment measures to express, for maintenance or technical personnel to provide reference.%原料气压缩机组为中海油化学股份有限公司海南基地80万 t 化肥装置合成设备。自投产以来该设备的维修任务一直都外委其他化工检修单位负责,2015年该设备的大修首次由本公司独自承担,本人就检修过程中遇到的问题及处理措施进行表述,为检修或技术人员提供参考。

  6. 40 CFR 63.1012 - Compressor standards.

    Science.gov (United States)

    2010-07-01

    ... is equipped with a system to capture and transport leakage from the compressor drive shaft seal to a... in the referencing subpart. (b) Seal system standard. Each compressor shall be equipped with a seal..., except as provided in § 63.1002(b) and paragraphs (e) and (f) of this section. Each compressor seal...

  7. 40 CFR 63.164 - Standards: Compressors.

    Science.gov (United States)

    2010-07-01

    ... from the compressor drive shaft seal back to a process or a fuel gas system or to a control device that... compressor shall be equipped with a seal system that includes a barrier fluid system and that prevents... paragraphs (h) and (i) of this section. (b) Each compressor seal system as required in paragraph (a) of this...

  8. Numerical analysis on centrifugal compressor with membrane type dryer

    Science.gov (United States)

    Razali, M. A.; Zulkafli, M. F.; Mat Isa, N.; Subari, Z.

    2017-09-01

    Moisture content is a common phenomenon in industrial processes especially in oil and gas industries. This contaminant has a lot of disadvantages which can lead to mechanical failure DEC (Deposition, Erosion & Corrosion) problems. To overcome DEC problem, this study proposed to design a centrifugal compressor with a membrane type dryer to reduce moisture content of a gas. The effectiveness of such design has been analyzed in this study using Computational Fluid Dynamics (CFD) approach. Numerical scheme based on multiphase flow technique is used in ANSYS Fluent software to evaluate the moisture content of the gas. Through this technique, two kind of centrifugal compressor, with and without membrane type dryer has been tested. The results show that the effects of pressure on dew point temperature of the gas change the composition of its moisture content, where high value lead more condensation to occur. However, with the injection of cool dry gas through membrane type dryer in the centrifugal compressor, the pressure and temperature of moisture content as well as mass fraction of H2O in centrifugal compressor show significant reduction.

  9. Trend and pattern analysis of failures of main feedwater system components in United States commercial nuclear power plants

    International Nuclear Information System (INIS)

    Gentillon, C.D.; Meachum, T.R.; Brady, B.M.

    1987-01-01

    The goal of the trend and pattern analysis of MFW (main feedwater) component failure data is to identify component attributes that are associated with relatively high incidences of failure. Manufacturer, valve type, and pump rotational speed are examples of component attributes under study; in addition, the pattern of failures among NPP units is studied. A series of statistical methods is applied to identify trends and patterns in failures and trends in occurrences in time with regard to these component attributes or variables. This process is followed by an engineering evaluation of the statistical results. In the remainder of this paper, the characteristics of the NPRDS that facilitate its use in reliability and risk studies are highlighted, the analysis methods are briefly described, and the lessons learned thus far for improving MFW system availability and reliability are summarized (orig./GL)

  10. Peritoneal dialysis in the neonatal intensive care unit. Management of acute renal failure after a severe subgaleal hemorrhage.

    Science.gov (United States)

    Coe, Kristi; Lail, Candace

    2007-08-01

    Acute renal failure is common in the neonatal intensive care unit but is often not recognized in its early phases, when it is potentially reversible. The typical patient with acute renal failure is premature, but many term infants are also at risk. One such group is those with severe bleeding, such as a subgaleal hemorrhage. In these cases, hypovolemia can quickly progress to ischemia, which affects many organs but has profound effects on the kidney. In term infants, acute renal failure is most commonly diagnosed in those with perinatal depression. This article presents a unique case of an infant with subgaleal and intracranial bleeding that resulted in acute renal failure requiring peritoneal dialysis in the hopes of the eventual restoration of kidney function.

  11. New technology of subsea and offshore compressor

    Energy Technology Data Exchange (ETDEWEB)

    Almasi, Amin

    2012-09-15

    Subsea compressor is a hot topic. Subsea compressor offers tremendous potentials, but also some obstacles. Active magnetic bearings installed inside the process gas allow the elimination of lubrication and seal systems. High-speed permanent- magnet motor directly drives centrifugal compressor to meet optimum speed, eliminating gear box. This design offers inherent machinery health monitoring features and very compact and reliable train. New technology of hermitically sealed direct drive centrifugal compressor for offshore and subsea applications are discussed and case studies for horizontal and vertical compressor train arrangements are presented. (orig.)

  12. Environmental management at the Grand Rapids Generating Station following the Unit No.1 headcover failure

    International Nuclear Information System (INIS)

    Windsor, D.C.

    1993-01-01

    Failure of the headcover of Unit 1 in the Grand Rapids generating station in March, 1992 caused the station to flood, releasing several thousand gallons of oil and removing the station from service for several weeks. Environmental considerations were a considerable part of the station restoration activities, reservoir and flow management programs and responses to public concerns arising from the accident. A major oil spill containment and cleanup program was undertaken, with station cleanup and debris disposal carried out in a manner acceptable to environmental authorities. Reservoir spillage was necessitated by the station shutdown. The spill recreated fish habitat in the spillway and walleye spawning were documented. A compensation program was developed to respond to problems caused by debris flushed from the spillway channel. On spill termination, a fish salvage program removed fish from a scour hole in the spillway channel. A proactive program of public information provided local residents with the facts about the incident and response program, and allayed concerns about public safety. 4 refs., 2 figs

  13. Part load efficiency of packaged air-cooled water chillers with inverter driven scroll compressors

    International Nuclear Information System (INIS)

    Cecchinato, Luca

    2010-01-01

    In this paper different packaged air-cooled systems, operating on scroll compressors, are experimentally analysed from the point of view of the relation between energy efficiency and actual capacity. Single compressor, double compressors and double compressors with uneven volumetric capacity units are tested. Experimental tests demonstrated that cooling capacity control by means of variation of rotational speed is an suitable solution for improving the part load efficiency of these systems. Step capacity units obtained by splitting the system volumetric capacity between two compressors are also effective solutions. Nevertheless they appear to be more efficient than single inverter driven chillers only for part load conditions lower than 60%. In the analysed cooling capacity range (25-50 kW), tandem compressors chillers with one inverter driven compressor appear the most efficient solution combining rotational speed with step capacity control. Seasonal energy efficiency ratios were obtained with prEN 14825 calculation method confirming reduced energy consumption associated to continuous and step cooling capacity control.

  14. Numerical investigation of refrigeration machine compressor operation considering single-phase electric motor dynamic characteristics

    Science.gov (United States)

    Baidak, Y.; Smyk, V.

    2017-08-01

    Using as the base the differential equations system which was presented in relative units for generalized electric motor of hermetic refrigeration compressor, mathematical model of the software for dynamic performance calculation of refrigeration machine compressors drive low-power asynchronous motors was developed. Performed on its ground calculations of the basic model of two-phase electric motor drive of hermetic compressor and the proposed newly developed model of the motor with single-phase stator winding, which is an alternative to the industrial motor winding, have confirmed the benefits of the motor with innovative stator winding over the base engine. Given calculations of the dynamic characteristics of compressor drive motor have permitted to determine the value of electromagnetic torque swinging for coordinating compressor and motor mechanical characteristics, and for taking them into consideration in choosing compressor elements construction materials. Developed and used in the process of investigation of refrigeration compressor drive asynchronous single-phase motor mathematical and software can be considered as an element of computer-aided design system for design of the aggregate of refrigeration compression unit refrigerating machine.

  15. Heat flows in piston compressors

    NARCIS (Netherlands)

    Lekic, U.; Kok, J.B.W.; van der Meer, T.H.; van Steenhoven, A.A.; Stoffels, G.G.M.

    2008-01-01

    Piston compressors are widely used in today's engineering applications. Among the most important applications is however the compression of thermal carrier gas in Rankine and Stirling refrigeration cycles. Fluids used in these cycles are commonly Ammonia and Helium. In order to improve the design

  16. Piping failures in United States nuclear power plants 1961-1995

    International Nuclear Information System (INIS)

    Bush, S.H.; Do, M.J.; Slavich, A.L.; Chockie, A.D.

    1996-01-01

    Over 1500 reported piping failures were identified and summarized based on an extensive review of tens of thousands of event reports that have been submitted to the US regulatory agencies over the last 35 years. The data base contains only piping failures; failures in vessels, pumps, valves and steam generators or any cracks that were not through-wall are not included. It was observed that there has been a marked decrease in the number of failures after 1983 for almost all sizes of pipes. This is likely due to the changes in the reporting requirements at that time and the corrective actions taken by utilities to minimize fatigue failures of small lines and IGSCC in BWRs. One failure mechanism that continues to occur is erosion-corrosion, which accounts for most of the ruptures reported and probably is responsible for the absence of downward trends in ruptures. Fatigue-vibration is also a significant contributor to piping failures. However, most of such events occur in lines approx. one inch or less in diameter. Together, erosion-corrosion and fatigue-vibration account for over 43 per cent of the failures. The overwhelming majority of failures have been leaks, over half the failures occurred in pipes with a diameter of one inch or less. Included in the report is a listing of the number of welds in various systems in LWRs

  17. Performance test of 100 W linear compressor

    Energy Technology Data Exchange (ETDEWEB)

    Ko, J; Ko, D. Y.; Park, S. J.; Kim, H. B.; Hong, Y. J.; Yeom, H. K. [Korea Institute of Machinery and Materials, Daejeon(Korea, Republic of)

    2013-09-15

    In this paper, we present test results of developed 100 W class linear compressor for Stirling-type pulse tube refrigerator. The fabricated linear compressor has dual-opposed configuration, free piston and moving magnet type linear motor. Power transfer, efficiency and required pressure waveform are predicted with designed and measured specifications. In experiments, room temperature test with flow impedance is conducted to evaluate performance of developed linear compressor. Flow impedance is loaded to compressor with metering valve for flow resistance, inertance tube for flow inertance and buffer volumes for flow compliance. Several operating parameters such as input voltage, current, piston displacement and pressure wave are measured for various operating frequency and fixed input current level. Behaviors of dynamics and performance of linear compressor as varying flow impedance are discussed with measured experimental results. The developed linear compressor shows 124 W of input power, 86 % of motor efficiency and 60 % of compressor efficiency at its resonant operating condition.

  18. Comprehensive model of a hermetic reciprocating compressor

    Science.gov (United States)

    Yang, B.; Ziviani, D.; Groll, E. A.

    2017-08-01

    A comprehensive simulation model is presented to predict the performance of a hermetic reciprocating compressor and to reveal the underlying mechanisms when the compressor is running. The presented model is composed of sub-models simulating the in-cylinder compression process, piston ring/journal bearing frictional power loss, single phase induction motor and the overall compressor energy balance among different compressor components. The valve model, leakage through piston ring model and in-cylinder heat transfer model are also incorporated into the in-cylinder compression process model. A numerical algorithm solving the model is introduced. The predicted results of the compressor mass flow rate and input power consumption are compared to the published compressor map values. Future work will focus on detailed experimental validation of the model and parametric studies investigating the effects of structural parameters, including the stroke-to-bore ratio, on the compressor performance.

  19. Using helical compressors for coke gas condensation

    Energy Technology Data Exchange (ETDEWEB)

    Privalov, V E; Rezunenko, Yu I; Lelyanov, N V; Zarnitzkii, G Eh; Gordienko, A A; Derebenko, I F; Venzhega, A G; Leonov, N P; Gorokhov, N N

    1982-08-01

    Coke oven gas compression is discussed. Presently used multilevel piston compressors are criticized. The paper recommends using helical machines which combine advantages of using volume condensing compressors and compact high-efficiency centrifugal machines. Two kinds of helical compressors are evaluated: dry and oil-filled; their productivities and coke oven gas chemical composition are analyzed. Experiments using helical compressors were undertaken at the Yasinovskii plant. Flowsheet of the installation is shown. Performance results are given in a table. For all operating conditions content of insolubles in oil compounds is found to be lower than the acceptable value (0.08%). Compressor productivity measurements with variable manifold pressure are evaluated. Figures obtained show that efficient condensation of raw coke oven gas is possible. Increasing oil-filled compressor productivity is recommended by decreasing amount of oil injected and simultaneously increasing rotation speed. The dry helical compressor with water seal is found to be most promising for raw coke oven gas condensation. (10 refs.)

  20. An exergy method for compressor performance analysis

    Energy Technology Data Exchange (ETDEWEB)

    McGovern, J A; Harte, S [Trinity Coll., Dublin (Ireland)

    1995-07-01

    An exergy method for compressor performance analysis is presented. The purpose of this is to identify and quantify defects in the use of a compressor`s shaft power. This information can be used as the basis for compressor design improvements. The defects are attributed to friction, irreversible heat transfer, fluid throttling, and irreversible fluid mixing. They are described, on a common basis, as exergy destruction rates and their locations are identified. The method can be used with any type of positive displacement compressor. It is most readily applied where a detailed computer simulation program is available for the compressor. An analysis of an open reciprocating refrigeration compressor that used R12 refrigerant is given as an example. The results that are presented consist of graphs of the instantaneous rates of exergy destruction according to the mechanisms involved, a pie chart of the breakdown of the average shaft power wastage by mechanism, and a pie chart with a breakdown by location. (author)

  1. Meridional Considerations of the Centrifugal Compressor Development

    Directory of Open Access Journals (Sweden)

    C. Xu

    2012-01-01

    Full Text Available Centrifugal compressor developments are interested in using optimization procedures that enable compressor high efficiency and wide operating ranges. Recently, high pressure ratio and efficiency of the centrifugal compressors require impeller design to pay attention to both the blade angle distribution and the meridional profile. The geometry of the blades and the meridional profile are very important contributions of compressor performance and structure reliability. This paper presents some recent studies of meridional impacts of the compressor. Studies indicated that the meridional profiles of the impeller impact the overall compressor efficiency and pressure ratio at the same rotational speed. Proper meridional profiles can improve the compressor efficiency and increase the overall pressure ratio at the same blade back curvature.

  2. Pulse compressor with aberration correction

    Energy Technology Data Exchange (ETDEWEB)

    Mankos, Marian [Electron Optica, Inc., Palo Alto, CA (United States)

    2015-11-30

    In this SBIR project, Electron Optica, Inc. (EOI) is developing an electron mirror-based pulse compressor attachment to new and retrofitted dynamic transmission electron microscopes (DTEMs) and ultrafast electron diffraction (UED) cameras for improving the temporal resolution of these instruments from the characteristic range of a few picoseconds to a few nanoseconds and beyond, into the sub-100 femtosecond range. The improvement will enable electron microscopes and diffraction cameras to better resolve the dynamics of reactions in the areas of solid state physics, chemistry, and biology. EOI’s pulse compressor technology utilizes the combination of electron mirror optics and a magnetic beam separator to compress the electron pulse. The design exploits the symmetry inherent in reversing the electron trajectory in the mirror in order to compress the temporally broadened beam. This system also simultaneously corrects the chromatic and spherical aberration of the objective lens for improved spatial resolution. This correction will be found valuable as the source size is reduced with laser-triggered point source emitters. With such emitters, it might be possible to significantly reduce the illuminated area and carry out ultrafast diffraction experiments from small regions of the sample, e.g. from individual grains or nanoparticles. During phase I, EOI drafted a set of candidate pulse compressor architectures and evaluated the trade-offs between temporal resolution and electron bunch size to achieve the optimum design for two particular applications with market potential: increasing the temporal and spatial resolution of UEDs, and increasing the temporal and spatial resolution of DTEMs. Specialized software packages that have been developed by MEBS, Ltd. were used to calculate the electron optical properties of the key pulse compressor components: namely, the magnetic prism, the electron mirror, and the electron lenses. In the final step, these results were folded

  3. Rotor-to-stator rub vibration in centrifugal compressor

    Science.gov (United States)

    Gao, J. J.; Qi, Q. M.

    1985-01-01

    One example of excessive vibration encountered during loading of a centrifugal compressor train (H type compressor with HP casing) is discussed. An investigation was made of the effects of the dynamic load on the bearing stiffness and the rotor-bearing system critical speed. The high vibration occurred at a "threshold load," but the machine didn't run smoothly due to rubs even when it had passed through the threshold load. The acquisition and discussion of the data taken in the field as well as a description of the case history which utilizes background information to identify the malfunction conditions is presented. The analysis shows that the failures, including full reverse precession rub and exact one half subharmonic vibration, were caused by the oversize bearings and displacement of the rotor center due to foundation deformation and misalignment between gear shafts, etc. The corrective actions taken to alleviate excessive vibration and the problems which remain to be solved are also presented.

  4. 20 CFR 404.450 - Required reports of work outside the United States or failure to have care of a child.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Required reports of work outside the United States or failure to have care of a child. 404.450 Section 404.450 Employees' Benefits SOCIAL SECURITY... Nonpayments of Benefits § 404.450 Required reports of work outside the United States or failure to have care...

  5. IEMDC IN-LINE ELECTRIC MOTOR DRIVEN COMPRESSOR

    Energy Technology Data Exchange (ETDEWEB)

    Michael J. Crowley; Prem N. Bansal

    2004-10-01

    This report contains the final project summary and deliverables required by the award for the development of an In-line Electric Motor Driven Compressor (IEMDC). Extensive work was undertaken during the course of the project to develop the motor and the compressor section of the IEMDC unit. Multiple design iterations were performed to design an electric motor for operation in a natural gas environment and to successfully integrate the motor with a compressor. During the project execution, many challenges were successfully overcome in order to achieve the project goals and to maintain the system design integrity. Some of the challenges included limiting the magnitude of the compressor aerodynamic loading for appropriate sizing of the magnetic bearings, achieving a compact motor rotor size to meet the rotor dynamic requirements of API standards, devising a motor cooling scheme using high pressure natural gas, minimizing the impact of cooling on system efficiency, and balancing the system thrust loads for the magnetic thrust bearing. Design methods that were used on the project included validated state-of-the-art techniques such as finite element analysis and computational fluid dynamics along with the combined expertise of both Curtiss-Wright Electro-Mechanical Corporation and Dresser-Rand Company. One of the most significant areas of work undertaken on the project was the development of the unit configuration for the system. Determining the configuration of the unit was a significant step in achieving integration of the electric motor into a totally enclosed compression system. Product review of the IEMDC unit configuration was performed during the course of the development process; this led to an alternate design configuration. The alternate configuration is a modular design with the electric motor and compressor section each being primarily contained in its own pressure containing case. This new concept resolved the previous conflict between the aerodynamic flow

  6. Flow Range of Centrifugal Compressor Being Extended

    Science.gov (United States)

    Skoch, Gary J.

    2001-01-01

    General Aviation will benefit from turbine engines that are both fuel-efficient and reliable. Current engines fall short of their potential to achieve these attributes. The reason is compressor surge, which is a flow stability problem that develops when the compressor is subjected to conditions that are outside of its operating range. Compressor surge can occur when fuel flow to the engine is increased, temporarily back pressuring the compressor and pushing it past its stability limit, or when the compressor is subjected to inlet flow-field distortions that may occur during takeoff and landing. Compressor surge can result in the loss of an aircraft. As a result, engine designers include a margin of safety between the operating line of the engine and the stability limit line of the compressor. Unfortunately, the most efficient operating line for the compressor is usually closer to its stability limit line than it is to the line that provides an adequate margin of safety. A wider stable flow range will permit operation along the most efficient operating line of the compressor, improving the specific fuel consumption of the engine and reducing emissions. The NASA Glenn Research Center is working to extend the stable flow range of the compressor. Significant extension has been achieved in axial compressors by injecting air upstream of the compressor blade rows. Recently, the technique was successfully applied to a 4:1 pressure ratio centrifugal compressor by injecting streams of air into the diffuser. Both steady and controlled unsteady injection were used to inject air through the diffuser shroud surface and extend the range. Future work will evaluate the effect of air injection through the diffuser hub surface and diffuser vanes with the goal of maximizing the range extension while minimizing the amount of injected air that is required.

  7. Development of Performance Analysis Program for an Axial Compressor with Meanline Analysis

    International Nuclear Information System (INIS)

    Park, Jun Young; Park, Moo Ryong; Choi, Bum Suk; Song, Je Wook

    2009-01-01

    Axial-flow compressor is one of the most important parts of gas turbine units with axial turbine and combustor. Therefore, precise prediction of performance is very important for development of new compressor or modification of existing one. Meanline analysis is a simple, fast and powerful method for performance prediction of axial-flow compressors with different geometries. So, Meanline analysis is frequently used in preliminary design stage and performance analysis for given geometry data. Much correlations for meanline analysis have been developed theoretically and experimentally for estimating various types of losses and flow deviation angle for long time. In present study, meanline analysis program was developed to estimate compressor losses, incidence angles, deviation angles, stall and surge conditions with many correlations. Performance prediction of one stage axial compressors is conducted with this meanline analysis program. The comparison between experimental and numerical results show a good agreement. This meanline analysis program can be used for various types of single stage axial-flow compressors with different geometries, as well as multistage axial-flow compressors

  8. Clinical risk analysis with failure mode and effect analysis (FMEA) model in a dialysis unit.

    Science.gov (United States)

    Bonfant, Giovanna; Belfanti, Pietro; Paternoster, Giuseppe; Gabrielli, Danila; Gaiter, Alberto M; Manes, Massimo; Molino, Andrea; Pellu, Valentina; Ponzetti, Clemente; Farina, Massimo; Nebiolo, Pier E

    2010-01-01

    The aim of clinical risk management is to improve the quality of care provided by health care organizations and to assure patients' safety. Failure mode and effect analysis (FMEA) is a tool employed for clinical risk reduction. We applied FMEA to chronic hemodialysis outpatients. FMEA steps: (i) process study: we recorded phases and activities. (ii) Hazard analysis: we listed activity-related failure modes and their effects; described control measures; assigned severity, occurrence and detection scores for each failure mode and calculated the risk priority numbers (RPNs) by multiplying the 3 scores. Total RPN is calculated by adding single failure mode RPN. (iii) Planning: we performed a RPNs prioritization on a priority matrix taking into account the 3 scores, and we analyzed failure modes causes, made recommendations and planned new control measures. (iv) Monitoring: after failure mode elimination or reduction, we compared the resulting RPN with the previous one. Our failure modes with the highest RPN came from communication and organization problems. Two tools have been created to ameliorate information flow: "dialysis agenda" software and nursing datasheets. We scheduled nephrological examinations, and we changed both medical and nursing organization. Total RPN value decreased from 892 to 815 (8.6%) after reorganization. Employing FMEA, we worked on a few critical activities, and we reduced patients' clinical risk. A priority matrix also takes into account the weight of the control measures: we believe this evaluation is quick, because of simple priority selection, and that it decreases action times.

  9. Universal failure model for multi-unit systems with shared functionality

    International Nuclear Information System (INIS)

    Volovoi, Vitali

    2013-01-01

    A Universal Failure Model (UFM) is proposed for complex systems that rely on a large number of entities for performing a common function. Economy of scale or other considerations may dictate the need to pool resources for common purpose, but the resulting strong coupling precludes the grouping of those components into modules. Existing system-level failure models rely on modularity for reducing modeling complexity, so the UFM will fill an important gap in constructing efficient system-level models. Conceptually, the UFM resembles cellular automata (CA) infused with realistic failure mechanisms. Components’ behavior is determined based on the balance between their strength (capacity) and their load (demand) share. If the load exceeds the components’ capacity, the component fails and its load share is distributed among its neighbors (possibly with a time delay and load losses). The strength of components can degrade with time if the load exceeds an elastic threshold. The global load (demand) carried by the system can vary over time, with the peak values providing shocks to the system (e.g., wind loads in civil structures, electricity demand, stressful activities to human bodies, or drought in an ecosystem). Unlike the models traditionally studied by CA, the focus of the presented model is on the system reliability, and specifically on the study of time-to-failure distributions, rather than steady-state patterns and average time-to-failure characteristics. In this context, the relationships between the types of failure distributions and the parameters of the failure model are discussed

  10. Double-yoke balanced compressor

    International Nuclear Information System (INIS)

    Durenec, P.

    1981-01-01

    A double-yoke balanced compressor for a cryogenic cooler that has only linear motion imparted to balanced piston and cylinder masses. A piston yoke is driven in the linear stroke direction by a piston axially offset crankshaft cam and a cylinder yoke is driven linearly by a cylinder axially offset crankshaft cam that is exactly offset 180 0 from the other cam. A large circular bushing in the compressor housing covers the entire outer cylinder head during linear operation to prevent blow by and to guide the cylinder linearly. The lower portion of the piston and cylinder connecting rods fit into linear guides that are further comprised of low molecular weight gas filled cavities to provide additional air bearing smoothness to the linear motion of the piston and cylinder

  11. Centrifugal and axial compressor control

    CERN Document Server

    McMillan, Gregory K

    2009-01-01

    Control engineers, mechanical engineers and mechanical technicians will learn how to select the proper control systems for axial and centrifugal compressors for proper throughput and surge control, with a particular emphasis on surge control. Readers will learn to understand the importance of transmitter speed, digital controller sample time, and control valve stroking time in helping to prevent surge. Engineers and technicians will find this book to be a highly valuable guide on compressor control schemes and the importance of mitigating costly and sometimes catastrophic surge problems. It can be used as a self-tutorial guide or in the classroom with the book's helpful end-of-chapter questions and exercises and sections for keeping notes.

  12. Magnetic power piston fluid compressor

    Science.gov (United States)

    Gasser, Max G. (Inventor)

    1994-01-01

    A compressor with no moving parts in the traditional sense having a housing having an inlet end allowing a low pressure fluid to enter and an outlet end allowing a high pressure fluid to exit is described. Within the compressor housing is at least one compression stage to increase the pressure of the fluid within the housing. The compression stage has a quantity of magnetic powder within the housing, is supported by a screen that allows passage of the fluid, and a coil for selectively providing a magnetic field across the magnetic powder such that when the magnetic field is not present the individual particles of the powder are separated allowing the fluid to flow through the powder and when the magnetic field is present the individual particles of the powder pack together causing the powder mass to expand preventing the fluid from flowing through the powder and causing a pressure pulse to compress the fluid.

  13. All-optical fiber compressor

    International Nuclear Information System (INIS)

    Ivanov, Luben M.

    2015-01-01

    A simple all-optical fiber compressor, based on an idea of dispersion management using a fiber of positive dispersion in the first part and of negative dispersion in the second one at the working wavelength, is investigated. The method allows a combination of the advantages of the classic fiber-grating and of the multisoliton compression. It is possible to improve substantially the quality of the compressed pulse compared to the multisoliton compression. The compression factor could be increased up to 2-2.5 times when the fraction of the input pulse energy appearing within the compressed pulse enhances more than 2 times. Thus, the peak power of the compressed pulse is able to increase about 5 times and the quality of the obtained pulses should be comparable with those obtained by the fiber-grating compressor

  14. Favorable bed utilization and readmission rates for emergency department observation unit heart failure patients.

    Science.gov (United States)

    Schrager, Justin; Wheatley, Matthew; Georgiopoulou, Vasiliki; Osborne, Anwar; Kalogeropoulos, Andreas; Hung, Olivia; Butler, Javed; Ross, Michael

    2013-06-01

    The objective was to compare readmission rates and hospital bed-days between acute decompensated heart failure (AHF) patients admitted or discharged following accelerated treatment protocol (ATP)-driven care in an emergency department observation unit (OU). This was a retrospective cohort study conducted at two urban university-affiliated hospitals. A total of 358 selected AHF patients received treatment on an ATP in the OU between October 1, 2007, and June 30, 2011. The comparison of interest was admission or discharge following OU treatment. The outcome of interest was readmission within 30 and 90 days of hospital discharge following care in the OU. We also examined resource use (inpatient, inpatient plus outpatient-days) between the admitted and discharged groups. Time to readmission analysis was performed with Cox proportional hazards regression. Discharged and admitted patients were similar with respect to age, race, sex, ED length of stay (LOS), and OU LOS. Patients admitted from the OU had a higher median B-type natriuretic peptide (BNP; 1,063 pg/mL [interquartile range {IQR} = 552 to 2,067 pg/mL] vs. 708 pg/mL [IQR = 254 to 1,683 pg/mL]; p = 0.002) and blood urea nitrogen (BUN; 19 mg/dL [IQR = 14 to 26 mg/dL] vs. 17 mg/dL [IQR = 13 to 23 mg/dL]) than those discharged (p = 0.04) and a lower median ejection fraction (EF; 22.5% [15% to 43%] vs. 35% [IQR 20% to 55%]; p = 0.002). In models controlling for age, race, sex, clinical site, BNP, BUN, creatinine, and EF, the 30-day readmission rate (13.8% in the study population as a whole) was not significantly different between the patients discharged or admitted following OU care (hazard ratio [HR] = 0.99; 95% confidence interval [CI] = 0.47 to 2.10). The readmission rates were also not significantly different at 90 days (HR = 1.07; 95% CI = 0.65 to 1.77). Within 30 days of discharge from the OU, patients spent a median of 1.7 days (IQR = 0.0 to 5.1 days) as inpatients, compared to 3.5 days (IQR = 2.3 to 5.8 days

  15. Axial-Centrifugal Compressor Program

    Science.gov (United States)

    1975-10-01

    Assembly . .. . .... ..... 33 5 Tie Bolt...... .. .. .. .. . *.. .. .. .. .. .. ... 34 6 Axial Compressor Rotor Assembly Runouts . . .. . 34 7 CCV Blow...1.796 Impeller Slip Factor ’Ce2/U 2 ) .91 Impeller Wheel Speed ft/sec 1992.2 Impellet ’.ip Radius in. 3.780 Blade Tip Metal Angle- deg 0 Numbec of Blades...test item to the next Phase V component test. The test vehicle final balance levels and rotor runouts were normal at teardown, and no rubsI were

  16. Algorithm for Controlling a Centrifugal Compressor

    Science.gov (United States)

    Benedict, Scott M.

    2004-01-01

    An algorithm has been developed for controlling a centrifugal compressor that serves as the prime mover in a heatpump system. Experimental studies have shown that the operating conditions for maximum compressor efficiency are close to the boundary beyond which surge occurs. Compressor surge is a destructive condition in which there are instantaneous reversals of flow associated with a high outlet-to-inlet pressure differential. For a given cooling load, the algorithm sets the compressor speed at the lowest possible value while adjusting the inlet guide vane angle and diffuser vane angle to maximize efficiency, subject to an overriding requirement to prevent surge. The onset of surge is detected via the onset of oscillations of the electric current supplied to the compressor motor, associated with surge-induced oscillations of the torque exerted by and on the compressor rotor. The algorithm can be implemented in any of several computer languages.

  17. Experimental investigation of hinged and spring loaded rolling piston compressors pertaining to a turbo rotary engine

    International Nuclear Information System (INIS)

    Okur, Melih; Akmandor, Ibrahim Sinan

    2011-01-01

    Hinged rolling piston compressor of a new thermodynamic cycle Pars engine promises high performance figures such as single stage high compression levels and higher volume flow discharge with competitively low input power and torque. The pumping characteristic of the present engine compressor unit has been increased by the implementation of a spring less vane configuration. The reciprocating vane which is usually operated by spring compression in air conditioning and refrigeration unit has been replaced by a hinge vane mechanism. At high speeds, the conventional spring loaded vane which is forced against the eccentrically moving rotor periphery does disconnect and starts rocking. With the new configuration, this mishap has been eliminated and subsequently resulting compressor pressure leaks have been avoided. Compressor experiments have been carried out at predetermined rotor speeds and compressed volume flow amounts and required shaft powers have been measured and derived accordingly. Experimentally determined pressure-volume relations have been compared with isentropic, isothermal, isochoric compressions as well as isobaric process. It is seen that at lower speeds, hinged vane compression is half way between isentropic and isochoric compressions whereas at high speed the compression process approaches further isochoric compression behavior. The isentropic compression efficiency of the hinged vane compressor is around 85% for pressures reaching 9 atm. - Research highlights: → Volume flow rate of rotary vane compressor unit has been increased by a hinged vane mechanism. → Hinged compressor pressure output is almost twice the performance of a spring loaded compressor. → The slipping and rocking of the spring loaded vane against the rolling piston have been eliminated.

  18. Reliability and Maintainability Analysis of a High Air Pressure Compressor Facility

    Science.gov (United States)

    Safie, Fayssal M.; Ring, Robert W.; Cole, Stuart K.

    2013-01-01

    This paper discusses a Reliability, Availability, and Maintainability (RAM) independent assessment conducted to support the refurbishment of the Compressor Station at the NASA Langley Research Center (LaRC). The paper discusses the methodologies used by the assessment team to derive the repair by replacement (RR) strategies to improve the reliability and availability of the Compressor Station (Ref.1). This includes a RAPTOR simulation model that was used to generate the statistical data analysis needed to derive a 15-year investment plan to support the refurbishment of the facility. To summarize, study results clearly indicate that the air compressors are well past their design life. The major failures of Compressors indicate that significant latent failure causes are present. Given the occurrence of these high-cost failures following compressor overhauls, future major failures should be anticipated if compressors are not replaced. Given the results from the RR analysis, the study team recommended a compressor replacement strategy. Based on the data analysis, the RR strategy will lead to sustainable operations through significant improvements in reliability, availability, and the probability of meeting the air demand with acceptable investment cost that should translate, in the long run, into major cost savings. For example, the probability of meeting air demand improved from 79.7 percent for the Base Case to 97.3 percent. Expressed in terms of a reduction in the probability of failing to meet demand (1 in 5 days to 1 in 37 days), the improvement is about 700 percent. Similarly, compressor replacement improved the operational availability of the facility from 97.5 percent to 99.8 percent. Expressed in terms of a reduction in system unavailability (1 in 40 to 1 in 500), the improvement is better than 1000 percent (an order of magnitude improvement). It is worthy to note that the methodologies, tools, and techniques used in the LaRC study can be used to evaluate

  19. Dense-plasma research using ballistic compressors

    International Nuclear Information System (INIS)

    Hess, H.

    1986-01-01

    An introduction is given to research on dense (or nonideal) plasmas which can be generated to advantage by ballistic compressors. Some properties of ballistic compressors are discussed especially in comparison with shock tubes. A short review is given on the history of these devices for high-pressure plasma generation. The present state of the art is reported including research on the two ZIE (Central Institute for Electron Physics) ballistic compressors. (author)

  20. Numerical simulation of radial compressor stage

    Science.gov (United States)

    Syka, T.; Luňáček, O.

    2013-04-01

    Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  1. Numerical simulation of radial compressor stage

    OpenAIRE

    Luňáček O.; Syka T.

    2013-01-01

    Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  2. Numerical simulation of radial compressor stage

    Directory of Open Access Journals (Sweden)

    Luňáček O.

    2013-04-01

    Full Text Available Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  3. Design features of fans, blowers, and compressors

    Science.gov (United States)

    Cheremisinoff, N. P.; Cheremisinoff, P. N.

    Fan engineering and compression machines are discussed. Basic aspects of fan performance and design are reviewed, and the design and performance characteristics of radial-flow fans, axial-flow fans, and controllable pitch fans are examined in detail. Air-conditioning systems are discussed, and noise, vibration, and mechanical considerations in fans are extensively examined. The thermodynamic principles governing compression machines are reviewed, and piston compressors, rotary compressors, blowers, and centrifugal compressors are discussed.

  4. Approach to novel design of CO2 based centrifugal compressor

    Directory of Open Access Journals (Sweden)

    Kura Tomasz

    2016-01-01

    Full Text Available Even though turbomachinery design issues have been investigated almost since the beginning of engineering, its optimization process is still important. With the development of refrigeration devices and ORC based distributed generation facilities, a need for efficient and low-energy compressors and turbines became even more demanding. Such machines working with typical fluid, like air, are well described, but there is a room regarding the fluids like CO2, vapour of organic fluids, etc. The main objective of present studies is to propose a numerical model of the centrifugal compressor, with CO2 as the working fluid. Such unit may be a part of refrigeration cycle. Commonly, the scroll or piston compressors are used in such cases, however some discussed disadvantages show that the novel designs should be looked for. Properly designed centrifugal compressors can have higher efficiency than the presently used. Three dimensional analyses of proposed geometries were conducted – using a model including heat, mass and momentum conservation laws as well as ideal gas law. Verification of the proposed mesh and results was performed in the basis of values obtained using theoretical and empirical equations. With about 700 000 control volumes in the validated model, error of the results was no higher than 5%, with only about 1% in regards to the thermal parameters. Two design proposals were analysed, with performance maps as the main comparison factor. Apart from performance characteristics, the pressure and velocity fields were presented, showing the process of flow structure optimization. The main goal was to reduce negative effects of pressure and velocity gradients on the performance. Proposed precursory design might be a good starting point for further development of compressors. The results of numerical analysis were promising and shows the possibility of proposed design usage in practical applications, however to obtain deep understanding of the

  5. Technical analysis of utilization suitability of various wind rotor’s types for compressor’s power driving

    Directory of Open Access Journals (Sweden)

    Radim Rybár

    2005-03-01

    Full Text Available Conception is from the converting of wind energy, which flows across the wind turbine in mechanic work needed for compressor working. The wind motor one part of energy transform into mechanical work, part of energy is unused and part of energy of stead flow is transformed into eddy after wind rotor.The aim was rendering of technical analysis for equipment, which would use the wind with parameters for chosen area and whole unit would supply power in peak demand. Unit consists of wind turbine, which pushes compressor. Compressor pumps air into the compressed air storage. The air is used for power producing in time of peak demand.

  6. Decision 99-27 application 1029022 - Petro-Canada Oil and Gas application to install compressors at the Wilson Creek gas plant and at LSD 3-19-43-4 W5M, Wilson Creek Field

    International Nuclear Information System (INIS)

    1999-11-01

    Petro-Canada Oil and Gas applied to the Alberta Energy and Utilities Board (EUB) for approval to add two new compressors at the existing Wilson Creek sour gas processing facility, and to construct and operate a new sour gas compressor station in Alberta. The application was made pursuant to Section 26 (1)(b) of the Oil and Gas Conservation Act and Sections 7.001, 9.020, and 15.050 of the Oil and Gas Conservation Regulations. The applications and interventions were considered at a hearing at the Last West Hall, Rimbley, Alberta, commencing 7 April 1999. The issues concerning the applications were: the need for and location of the compressors, plant life, emissions, sulphur recovery, and noise. Petro-Canada will proceed with its commitment to local landowners to install and commission a sulphur recovery unit within 16 months of the date of this report. The sulphur recovery capability of the facility will meet guidelines defined in IL 88-13 for new sour gas plants based on either the current or an acceptable maximum daily inlet sulphur rate. Continuous-vent gas streams, including glycol regenerator, produced-water tank, and hydrocarbon condensate tank vents, at both the 3-29 compressor and at the Wilson Creek plant site will be burned in a flare or incinerator. Flare stacks at the 3-19 compressor site will be equipped with a suitable pilot and automatic igniter. The Wilson Creek plant flare system will be equipped with a suitable pilot, as well as automatic igniter and/or flame failure detection system. Petro-Canada will implement local ambient air quality monitoring and sound level monitoring consistent with its commitments to local landowners and regulatory requirements

  7. 5-year operation experience with the 1.8 K refrigeration units of the LHC cryogenic system

    CERN Document Server

    Ferlin, G; Claudet, S; Pezzetti, M

    2015-01-01

    Since 2009, the Large Hadron Collider (LHC) is in operation at CERN. The LHC superconducting magnets distributed over eight sectors of 3.3-km long are cooled at 1.9 K in pressurized superfluid helium. The nominal operating temperature of 1.9 K is produced by eight 1.8-K refrigeration units based on centrifugal cold compressors (3 or 4 stages depending to the vendor) combined with warm volumetric screw compressors with sub-atmospheric suction. After about 5 years of continuous operation, we will present the results concerning the availability for the final user of these refrigeration units and the impact of the design choice on the recovery time after a system trip. We will also present the individual results for each rotating machinery in terms of failure origin and of Mean Time between Failure (MTBF), as well as the consolidations and upgrades applied to these refrigeration units.

  8. 5-year operation experience with the 1.8 K refrigeration units of the LHC cryogenic system

    Science.gov (United States)

    Ferlin, G.; Tavian, L.; Claudet, S.; Pezzetti, M.

    2015-12-01

    Since 2009, the Large Hadron Collider (LHC) is in operation at CERN. The LHC superconducting magnets distributed over eight sectors of 3.3-km long are cooled at 1.9 K in pressurized superfluid helium. The nominal operating temperature of 1.9 K is produced by eight 1.8-K refrigeration units based on centrifugal cold compressors (3 or 4 stages depending to the vendor) combined with warm volumetric screw compressors with sub-atmospheric suction. After about 5 years of continuous operation, we will present the results concerning the availability for the final user of these refrigeration units and the impact of the design choice on the recovery time after a system trip. We will also present the individual results for each rotating machinery in terms of failure origin and of Mean Time between Failure (MTBF), as well as the consolidations and upgrades applied to these refrigeration units.

  9. Engineering task plan for BX/BY compressor upgrade

    International Nuclear Information System (INIS)

    Strand, R.G.

    1995-01-01

    This Engineering Task Plan outlines the remaining work to be completed for the BX/BY Instrument Air upgrade. Initial work efforts were guided by Engineering Work Plan, ''BX-BY Compressor Upgrade'' dated 1-25-93 (see Attachment A) which is provided for information. The overall engineering task is to provide a permanent replacement for the instrument air supply system for the 241-BX/BY Tank Farms. The existing system consists of a 25 horsepower Worthington non-lube compressor and an Oriad air dryer. The existing equipment is dated, requires high maintenance and is located in a contaminated zone making it unusable. The BX/BY instrument air replacement unit will be one of the 100 SCFM generic air stations. This station will be permanently sited with the addition of drawing changes to provide a concrete foundation, air piping to existing lines and electrical power supply tie-ins

  10. 30 CFR 75.344 - Compressors.

    Science.gov (United States)

    2010-07-01

    ... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.344 Compressors. (a) Except compressors that are...), shall be equipped with a heat activated fire suppression system meeting the requirements of 75.1107-3...

  11. 40 CFR 63.1031 - Compressors standards.

    Science.gov (United States)

    2010-07-01

    ... the compressor drive shaft seal to a process or a fuel gas system or to a closed vent system that... specified in the referencing subpart. (b) Seal system standard. Each compressor shall be equipped with a seal system that includes a barrier fluid system and that prevents leakage of process fluid to the...

  12. Air compressor efficiency in a Vietnamese enterprise

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming [3E and T International, Suite 1506, Building No. 10, Luo Ma Shi Street, Xuan Wu District, Beijing 100052 (China)

    2009-06-15

    Compressed air systems in a Vietnamese footwear manufacturing enterprise consume about 10% of enterprise's total electric power supply. Energy efficiency of these air compressor systems, either equipped with new and efficient compressors or old and inefficient ones, can only reach between 5% and 10%. In other words, regardless whatever air compressors were installed, energy loss from the compressor systems was over 80%. This study discovered that energy loss was due to non-optimized operations of the air compressor systems and air leakages. The objectives of the paper are to uncover energy saving potential in Vietnamese air compressor systems, demonstrate methodologies used in the auditing and assessment, share auditing and assessment results, and serve a guide on how to analyze energy efficiency in a compressed air system. This paper concludes that energy efficiency investment in air compressor systems in the Vietnamese enterprise could be extremely cost-effective. If the enterprise invests USD 84,000 in the air compressors to improve efficiency performance, the investment capital will be recovered in about six months. The net present value of the investment will be about USD 864,000 at a discount rate of 12%. (author)

  13. Air compressor efficiency in a Vietnamese enterprise

    Energy Technology Data Exchange (ETDEWEB)

    Yang Ming [3E and T International, Suite 1506, Building No. 10, Luo Ma Shi Street, Xuan Wu District, Beijing 100052 (China)], E-mail: ming.yang7@gmail.com

    2009-06-15

    Compressed air systems in a Vietnamese footwear manufacturing enterprise consume about 10% of enterprise's total electric power supply. Energy efficiency of these air compressor systems, either equipped with new and efficient compressors or old and inefficient ones, can only reach between 5% and 10%. In other words, regardless whatever air compressors were installed, energy loss from the compressor systems was over 80%. This study discovered that energy loss was due to non-optimized operations of the air compressor systems and air leakages. The objectives of the paper are to uncover energy saving potential in Vietnamese air compressor systems, demonstrate methodologies used in the auditing and assessment, share auditing and assessment results, and serve a guide on how to analyze energy efficiency in a compressed air system. This paper concludes that energy efficiency investment in air compressor systems in the Vietnamese enterprise could be extremely cost-effective. If the enterprise invests USD 84,000 in the air compressors to improve efficiency performance, the investment capital will be recovered in about six months. The net present value of the investment will be about USD 864,000 at a discount rate of 12%.

  14. Air compressor efficiency in a Vietnamese enterprise

    International Nuclear Information System (INIS)

    Yang Ming

    2009-01-01

    Compressed air systems in a Vietnamese footwear manufacturing enterprise consume about 10% of enterprise's total electric power supply. Energy efficiency of these air compressor systems, either equipped with new and efficient compressors or old and inefficient ones, can only reach between 5% and 10%. In other words, regardless whatever air compressors were installed, energy loss from the compressor systems was over 80%. This study discovered that energy loss was due to non-optimized operations of the air compressor systems and air leakages. The objectives of the paper are to uncover energy saving potential in Vietnamese air compressor systems, demonstrate methodologies used in the auditing and assessment, share auditing and assessment results, and serve a guide on how to analyze energy efficiency in a compressed air system. This paper concludes that energy efficiency investment in air compressor systems in the Vietnamese enterprise could be extremely cost-effective. If the enterprise invests USD 84,000 in the air compressors to improve efficiency performance, the investment capital will be recovered in about six months. The net present value of the investment will be about USD 864,000 at a discount rate of 12%.

  15. A high pressure centrifugal oxygen compressor

    International Nuclear Information System (INIS)

    Larsen, L.P.

    1986-01-01

    The application of a centrifugal compressor train to 5860 kPa(g) (850 psig) for a coal gasification plant is discussed. Special considerations in the application, installation, and operation of the equipment are presented. Discussion includes such topics as compressor controls, machinery protection, noise, personnel safety, and operation of the equipment

  16. Modeling and control of compressor flow instabilities

    NARCIS (Netherlands)

    Willems, F.P.T.; Jager, de A.G.

    1999-01-01

    Compressors are widely used for the pressurization of fluids. Applications involve air compression for use in aircraft engines and pressurization and transportation of gas in the process and chemical industries. The article focuses on two commonly used types of continuous flow compressors: the axial

  17. Regulatory analysis for the resolution of Generic Issue 130: Essential service water system failures at multi-unit sites

    International Nuclear Information System (INIS)

    Leung, V.; Basdekas, D.; Mazetis, G.

    1991-06-01

    The essential service water system (ESWS) is required to provide cooling in nuclear power plants during normal operation and accident conditions. The ESWS typically supports component cooling water heat exchangers, containment spray heat exchangers, high-pressure injection pump oil coolers, emergency diesel generators, and auxiliary building ventilation coolers. Failure of the ESWS function could lead to severe consequences. This report presents the regulatory analysis for GI-130, ''Essential Service Water System Failures at Multi-Unit Sites.'' The risk reduction estimates, cost/benefit analyses, and other insights gained during this effort have shown that implementation of the recommendations will significantly reduce risk and that these improvements are warranted in accordance with the backfit rule, 10 CFR 50.109(a)(3). 19 refs., 16 tabs

  18. Fast reversible wavelet image compressor

    Science.gov (United States)

    Kim, HyungJun; Li, Ching-Chung

    1996-10-01

    We present a unified image compressor with spline biorthogonal wavelets and dyadic rational filter coefficients which gives high computational speed and excellent compression performance. Convolutions with these filters can be preformed by using only arithmetic shifting and addition operations. Wavelet coefficients can be encoded with an arithmetic coder which also uses arithmetic shifting and addition operations. Therefore, from the beginning to the end, the while encoding/decoding process can be done within a short period of time. The proposed method naturally extends form the lossless compression to the lossy but high compression range and can be easily adapted to the progressive reconstruction.

  19. Refrigeration system having standing wave compressor

    Science.gov (United States)

    Lucas, Timothy S.

    1992-01-01

    A compression-evaporation refrigeration system, wherein gaseous compression of the refrigerant is provided by a standing wave compressor. The standing wave compressor is modified so as to provide a separate subcooling system for the refrigerant, so that efficiency losses due to flashing are reduced. Subcooling occurs when heat exchange is provided between the refrigerant and a heat pumping surface, which is exposed to the standing acoustic wave within the standing wave compressor. A variable capacity and variable discharge pressure for the standing wave compressor is provided. A control circuit simultaneously varies the capacity and discharge pressure in response to changing operating conditions, thereby maintaining the minimum discharge pressure needed for condensation to occur at any time. Thus, the power consumption of the standing wave compressor is reduced and system efficiency is improved.

  20. Centrifugal compressor design for electrically assisted boost

    International Nuclear Information System (INIS)

    Yang, M Y; Martinez-Botas, R F; Zhuge, W L; Qureshi, U; Richards, B

    2013-01-01

    Electrically assisted boost is a prominent method to solve the issues of transient lag in turbocharger and remains an optimized operation condition for a compressor due to decoupling from turbine. Usually a centrifugal compressor for gasoline engine boosting is operated at high rotational speed which is beyond the ability of an electric motor in market. In this paper a centrifugal compressor with rotational speed as 120k RPM and pressure ratio as 2.0 is specially developed for electrically assisted boost. A centrifugal compressor including the impeller, vaneless diffuser and the volute is designed by meanline method followed by 3D detailed design. Then CFD method is employed to predict as well as analyse the performance of the design compressor. The results show that the pressure ratio and efficiency at design point is 2.07 and 78% specifically

  1. Application of failure mode and effect analysis in managing catheter-related blood stream infection in intensive care unit.

    Science.gov (United States)

    Li, Xixi; He, Mei; Wang, Haiyan

    2017-12-01

    In this study, failure mode and effect analysis (FMEA), a proactive tool, was applied to reduce errors associated with the process which begins with assessment of patient and ends with treatment of complications. The aim of this study is to assess whether FMEA implementation will significantly reduce the incidence of catheter-related bloodstream infections (CRBSIs) in intensive care unit.The FMEA team was constructed. A team of 15 medical staff from different departments were recruited and trained. Their main responsibility was to analyze and score all possible processes of central venous catheterization failures. Failure modes with risk priority number (RPN) ≥100 (top 10 RPN scores) were deemed as high-priority-risks, meaning that they needed immediate corrective action. After modifications were put, the resulting RPN was compared with the previous one. A centralized nursing care system was designed.A total of 25 failure modes were identified. High-priority risks were "Unqualified medical device sterilization" (RPN, 337), "leukopenia, very low immunity" (RPN, 222), and "Poor hand hygiene Basic diseases" (RPN, 160). The corrective measures that we took allowed a decrease in the RPNs, especially for the high-priority risks. The maximum reduction was approximately 80%, as observed for the failure mode "Not creating the maximal barrier for patient." The averaged incidence of CRBSIs was reduced from 5.19% to 1.45%, with 3 months of 0 infection rate.The FMEA can effectively reduce incidence of CRBSIs, improve the security of central venous catheterization technology, decrease overall medical expenses, and improve nursing quality. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

  2. Technical evaluation report on the seven main transformer failures at the North Anna Power Station, Units 1 and 2 (Docket Nos. 50-338, 50-339)

    International Nuclear Information System (INIS)

    Dalton, K.J.; Kresser, J.V.; Savage, J.W.; Selan, J.C.

    1984-01-01

    This report documents technical evaluations on various aspects pertaining to the seven main transformer failures at the North Anna Power Station, Units 1 and 2. These reports cover the subjects of Probability Risk Assessment (PRA), Failure Modes and Effects Analysis (FMEA), Root Causes, Protection Systems, Modifications, Failure Statistics, and Generic Aspects. The PRA determined that the contribution from a main transformer failure affecting plant safety systems so as to increase the risk to the public health and safety is negligible. The FMEA determined that a main transformer failure can have primary and secondary effects on plant safety system operation. The evaluation of the Root Causes found that no single common cause contributed to the seven failures. Each failure was found to have specific circumstances for initiating the failure. Both the generator and transformer primary protection systems were found to perform correctly and were designed within industry standards and practices. The proposed modifications resulting from the analyses of the failures will improve system reliability and integrity, and will reduce potentially damaging effects. The failure statistic survey found very limited data bases from which a meaningful correlation could be ascertained. The statistical comparison found no appreciable anomalies with the NAPS failures. The evaluation of all the available information and the results of the separate reports on the main transformer failures found that several generic concerns exist

  3. Failure in Success; An Assessment of Agricultural Extension in the United States.

    Science.gov (United States)

    Carlson, Robert A.

    The United States formalized its cooperative national support program for agricultural extension in 1941. The hope was to increase agricultural production and to help maintain a rural way of life in the United States. The Cooperative Extension Service was unable to strike a balance between these two goals, emphasizing increased production to such…

  4. Positive predictive value and impact of misdiagnosis of a heart failure diagnosis in administrative registers among patients admitted to a University Hospital cardiac care unit

    DEFF Research Database (Denmark)

    Mard, Shan; Nielsen, Finn Erland

    2010-01-01

    To evaluate the positive predictive value (PPV) of a diagnosis of heart failure (HF) in the Danish National Registry of Patients (NRP) among patients admitted to a University Hospital cardiac care unit, and to evaluate the impact of misdiagnosing HF.......To evaluate the positive predictive value (PPV) of a diagnosis of heart failure (HF) in the Danish National Registry of Patients (NRP) among patients admitted to a University Hospital cardiac care unit, and to evaluate the impact of misdiagnosing HF....

  5. Cold War Agency: The United States and the Failure of the DIEM Experiment

    Science.gov (United States)

    2017-03-01

    the United States by complying with Western norms of democratic leadership , only later developing into an autocratic tyrant; or was Diem’s...2000s to establish democratic regimes in Afghanistan and Iraq reflect an American foreign policy tradition that began at the end of World War II. The...would eventually serve in Vietnam in a failed effort to prevent the Democratic Republic of Vietnam from uniting the country under a communist regime

  6. 33 CFR 154.826 - Vapor compressors and blowers.

    Science.gov (United States)

    2010-07-01

    ...) Excessive shaft bearing temperature. (d) If a centrifugal compressor, fan, or lobe blower handles vapor in... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vapor compressors and blowers....826 Vapor compressors and blowers. (a) Each inlet and outlet to a compressor or blower which handles...

  7. Success/Failure Prediction of Noninvasive Mechanical Ventilation in Intensive Care Units. Using Multiclassifiers and Feature Selection Methods.

    Science.gov (United States)

    Martín-González, Félix; González-Robledo, Javier; Sánchez-Hernández, Fernando; Moreno-García, María N

    2016-05-17

    This paper addresses the problem of decision-making in relation to the administration of noninvasive mechanical ventilation (NIMV) in intensive care units. Data mining methods were employed to find out the factors influencing the success/failure of NIMV and to predict its results in future patients. These artificial intelligence-based methods have not been applied in this field in spite of the good results obtained in other medical areas. Feature selection methods provided the most influential variables in the success/failure of NIMV, such as NIMV hours, PaCO2 at the start, PaO2 / FiO2 ratio at the start, hematocrit at the start or PaO2 / FiO2 ratio after two hours. These methods were also used in the preprocessing step with the aim of improving the results of the classifiers. The algorithms provided the best results when the dataset used as input was the one containing the attributes selected with the CFS method. Data mining methods can be successfully applied to determine the most influential factors in the success/failure of NIMV and also to predict NIMV results in future patients. The results provided by classifiers can be improved by preprocessing the data with feature selection techniques.

  8. Conceptual Design of Automotive Compressor for Integrated Portable Air Conditioning System

    Directory of Open Access Journals (Sweden)

    Ishak Muhammad Ikman

    2017-01-01

    Full Text Available This study introduces a new concept of portable air conditioner which integrated with some available components in automotive air conditioning system. This new idea intends to solve the storage problems as well as to reduce the price of current portable air conditioner since some devices could directly be used from the automotive air conditioning system. The primary emphasis of this study was on the modification of automotive compressor design so as the system may alternately be operated. The length of conventional compressor shaft is extended to place an additional clutch pulley, a drive plate and a clutch coil. The new concept particularly the shaft and pulley were analysed through slope deflection and computational finite element analyses. The result of engineering analyses exhibited that the new design of compressor shaft and clutch pulleys promote a low risk of failure as the data values recorded are lower than the critical value for each criterion investigated.

  9. Meteorological Satellites (METSAT) and Earth Observing System (EOS) Advanced Microwave Sounding Unit-A (AMSU-A) Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL)

    Science.gov (United States)

    1996-01-01

    This Failure Modes and Effects Analysis (FMEA) is for the Advanced Microwave Sounding Unit-A (AMSU-A) instruments that are being designed and manufactured for the Meteorological Satellites Project (METSAT) and the Earth Observing System (EOS) integrated programs. The FMEA analyzes the design of the METSAT and EOS instruments as they currently exist. This FMEA is intended to identify METSAT and EOS failure modes and their effect on spacecraft-instrument and instrument-component interfaces. The prime objective of this FMEA is to identify potential catastrophic and critical failures so that susceptibility to the failures and their effects can be eliminated from the METSAT/EOS instruments.

  10. High-energy pulse compressor using self-defocusing spectral broadening in anomalously dispersive media

    DEFF Research Database (Denmark)

    2015-01-01

    (3) with a net positive dispersion. Furthermore, the net positive dispersion in the dispersive unit at least partially compensates for the negative nonlinear phase variation and the negative group-velocity dispersion produced by the bulk quadratic nonlinear medium when the optical pulse passes......A method and a pulse compressor (1) for compressing an optical pulse, wherein the pulse compressor comprising a bulk quadratic nonlinear medium (2) adapted for generating a negative nonlinear phase variation on the optical pulse and having a negative group-velocity dispersion, and a dispersive unit...

  11. Persistence and failure of mean-field approximations adapted to a class of systems of delay-coupled excitable units

    Science.gov (United States)

    Franović, Igor; Todorović, Kristina; Vasović, Nebojša; Burić, Nikola

    2014-02-01

    We consider the approximations behind the typical mean-field model derived for a class of systems made up of type II excitable units influenced by noise and coupling delays. The formulation of the two approximations, referred to as the Gaussian and the quasi-independence approximation, as well as the fashion in which their validity is verified, are adapted to reflect the essential properties of the underlying system. It is demonstrated that the failure of the mean-field model associated with the breakdown of the quasi-independence approximation can be predicted by the noise-induced bistability in the dynamics of the mean-field system. As for the Gaussian approximation, its violation is related to the increase of noise intensity, but the actual condition for failure can be cast in qualitative, rather than quantitative terms. We also discuss how the fulfillment of the mean-field approximations affects the statistics of the first return times for the local and global variables, further exploring the link between the fulfillment of the quasi-independence approximation and certain forms of synchronization between the individual units.

  12. Respiratory failure in tetanic patient: maintenance of airway problem in intensive care unit setting

    Science.gov (United States)

    Utami, I. N.; Arifin; Susilo, R. S. B.; Redhono, D.; Sumandjar, T.

    2018-03-01

    Tetanus is a toxin-mediated disease caused by Clostridium tetani resulting in muscular stiffness and painful spasm. The case fatality rates are high (10-80%), and the most frequent cause of mortality is airway problem that results in respiratory failure. A 52-year-old malecame to the hospital with lockjaw, rhesussardonicus, opisthotonus, and seizure for the last 12 hours, diagnosed with tetanus grade II. We placed the patient in an isolation room, gave 3000U tetanus immunoglobulin, 20mg diazepam in 500ml dextrose 5%/8 hours, and 500mg/6hrs metronidazole. On the seventh day, seizure became frequent, respiratory rate increased with crackles found on the auscultation, and the blood gas analysis showed respiratory failure type II (PCO2 53mmHg). The patientwas immediately sent to the ICU, intubated and given ventilator support. The patientwas sedated with continuous injection of midazolam 3 mg/h, morphine 10mcg/kgBW/h and also levofloxacin 750mg/24hours. Bronchoalveolar lavage culture was positive for Acinetobacter baumanii, so we changed the antibiotic to amikacin injection 500 mg/8hrs. After four days, we extubated the ventilator and transferred from HCU three days later. The patient was fully recovered and discharged after eighteen days of hospitalization.

  13. Investigation of axial positioning for flexural compressors

    Science.gov (United States)

    Riggle, Peter

    1991-01-01

    The testing of the research compressor is presented. The research compressor was assembled and disassembled in order to show the consistency in which the piston and rod could be aligned with a .0004 inch radial gap around the piston. A full set of tests was completed for the first assembly, which is referred to as assembly no. 1. The compressor was disassembled and assembled a second time (assembly no. 2). Assembly no. 2 was only tested statically due to the time constraint. Results are discussed.

  14. Compressor Has No Moving Macroscopic Parts

    Science.gov (United States)

    Gasser, Max

    1995-01-01

    Compressor containing no moving macroscopic parts functions by alternating piston and valve actions of successive beds of magnetic particles. Fabricated easily because no need for precisely fitting parts rotating or sliding on each other. Also no need for lubricant fluid contaminating fluid to be compressed. Compressor operates continuously, eliminating troublesome on/off cycling of other compressors, and decreasing consumption of energy. Phased cells push fluid from bottom to top, adding increments of pressure. Each cell contains magnetic powder particles loose when electromagnet coil deenergized, but tightly packed when coil energized.

  15. Compressor Part I: Measurement and Design Modeling

    Directory of Open Access Journals (Sweden)

    Thomas W. Bein

    1999-01-01

    method used to design the 125-ton compressor is first reviewed and some related performance curves are predicted based on a quasi-3D method. In addition to an overall performance measurement, a series of instruments were installed on the compressor to identify where the measured performance differs from the predicted performance. The measurement techniques for providing the diagnostic flow parameters are also described briefly. Part II of this paper provides predictions of flow details in the areas of the compressor where there were differences between the measured and predicted performance.

  16. Compressor ported shroud for foil bearing cooling

    Science.gov (United States)

    Elpern, David G [Los Angeles, CA; McCabe, Niall [Torrance, CA; Gee, Mark [South Pasadena, CA

    2011-08-02

    A compressor ported shroud takes compressed air from the shroud of the compressor before it is completely compressed and delivers it to foil bearings. The compressed air has a lower pressure and temperature than compressed outlet air. The lower temperature of the air means that less air needs to be bled off from the compressor to cool the foil bearings. This increases the overall system efficiency due to the reduced mass flow requirements of the lower temperature air. By taking the air at a lower pressure, less work is lost compressing the bearing cooling air.

  17. Rotary Compressor Noise Analysis Using Mechanisms and Electromagnetics Coupled Approach

    OpenAIRE

    Chung, Jinah; Lee, Uiyoon; Lee, Jeongbae; Lee, Unseop; Han, Eunsil; Yoon, Jinhwan

    2016-01-01

    This research is conducted to investigate noise source and design low noise compressors. For improving energy efficiency, the rotary compressor with variable speed brushless DC motor is increasingly adopted for appliances. However brushless DC motor makes more compressor vibration than constant speed motor compressor at high speed operating condition. Therefore it is necessary to reduce noise and vibration for improving air conditioner quality. In this study, compressor’s noise and vibrat...

  18. Dependence of the mean time to failure of a hydraulic balancing machine unit on different factors for sectional pumps of the Alrosa JSC

    Science.gov (United States)

    Ovchinnikov, N. P.; Portnyagina, V. V.; Sobakina, M. P.

    2017-12-01

    This paper presents factors that have a greater impact on the mean time to failure of a hydraulic balancing machine unit working in underground kimberlite mines of the Alrosa JSC, the hydraulic balancing machine unit being the least reliable structural elements in terms of error-free operation. In addition, a multifactor linear dependence of mean time to failure of a hydraulic balancing machine unit is shown regarding it being parts of stage sectional pumps in the underground kimberlite mines of the Alrosa JSC. In prospect, this diagram can allow us to predict the durability of the least reliable structural element of a sectional pump.

  19. Copenhagen failure : a rhetorical treatise of how speeches unite and divide mankind

    OpenAIRE

    Kortetmäki, Teea

    2010-01-01

    The purpose of this treatise is to analyse five of the Copenhagen Climate Convention's main speeches to see how they supported or weakened the agreement possibilities in the convention. Particular focus will be on the elements that divide or unite negotiators and whether the summit's failing outcome is already built in the pre-planned speeches held at the main podium. Theoretically, the study builds on Kenneth Burke's identification thesis and Elizabeth L. Malone's climate change debate an...

  20. The United States Government Interagency Process and the Failure of Institution Building in Iraq

    Science.gov (United States)

    2008-06-12

    warehouses they were amazed to find pallets and pallets full of medical equipment from floor to ceiling that had had been in the warehouses for some... glass broken; and books and documents strewn about?”27 24 Durch, William ed. “Twenty-First-Century Peace Operations.” United States Institute of...health) to actors that potentially threaten domestic or international order (e.g., Egypt, Palestinian Authority, Lebanon ) Exploitation of legal

  1. 40 CFR 65.112 - Standards: Compressors.

    Science.gov (United States)

    2010-07-01

    ... the compressor stuffing box pressure at all times (except during periods of start-up, shutdown, or... process stream. (c) Barrier fluid system. The barrier fluid shall not be in light liquid service. Each...

  2. 40 CFR 265.1053 - Standards: Compressors.

    Science.gov (United States)

    2010-07-01

    ...) Operated with the barrier fluid at a pressure that is at all times greater than the compressor stuffing box... purges the barrier fluid into a hazardous waste stream with no detectable emissions to atmosphere. (c...

  3. 40 CFR 264.1053 - Standards: Compressors.

    Science.gov (United States)

    2010-07-01

    ... with the barrier fluid at a pressure that is at all times greater than the compressor stuffing box... purges the barrier fluid into a hazardous waste stream with no detectable emissions to atmosphere. (c...

  4. Turbofan compressor dynamics during afterburner transients

    Science.gov (United States)

    Kurkov, A. P.

    1976-01-01

    The effects of afterburner light-off and shut-down transients on the compressor stability are investigated. The reported experimental results are based on detailed high response pressure and temperature measurements on the TF30-P-3 turbofan engine. The tests were performed in an altitude test chamber simulating high altitude engine operation. It is shown that during both types of transients, flow breaks down in the forward part of the fan bypass duct. At a sufficiently low engine inlet pressure this resulted in a compressor stall. Complete flow breakdown within the compressor was preceded by a rotating stall. At some locations in the compressor, rotating stall cells initially extended only through part of the blade span. For the shutdown transient the time between first and last detected occurrence of rotating stall is related to the flow Reynolds number. An attempt was made to deduce the number and speed of propagation of rotating stall cells.

  5. Environmental risk assessment of low density polyethylene unit using the method of failure mode and effect analysis

    Directory of Open Access Journals (Sweden)

    Salati Parinaz

    2012-01-01

    Full Text Available The ninth olefin plan of Arya Sasol Petrochemical Company (A.S.P.C. is regarded the largest gas Olefin Unit located on Pars Special Economic Energy Zone (P.S.E.E.Z. Considering the importance of the petrochemical unit, its environmental assessment seems necessary to identify and reduce potential hazards. For this purpose, after determining the scope of the study area, identification and measurement of the environmental parameters, environmental risk assessment of the unit was carried out using Environment Failure Mode and Effect Analysis (EFMEA. Using the noted method, sources causing environmental risks were identified, rated and prioritized. Beside, the impacts of the environmental aspects derived from the unit activities as well as their consequences were also analyzed. Furthermore, the identified impacts were prioritized based on Risk Priority Number (RPN and severity level of the consequences imposed on the affected environment. After performing statistical calculations, it was found that the environmental aspects owing the risk priority number higher than 15 have a high level of risk. Results obtained from Low Density Polyethylene Unit revealed that the highest risk belongs to the emergency vent system with risk priority number equal to 48. It is occurred due to imperfect performance of the reactor safety system leading to the emissions of ethylene gas, particles, and radioactive steam as well as air and noise pollutions. Results derived from secondary assessment of the environmental aspects, through difference in calculated RPN and activities risk levels showed that employing modern methods and risk assessment are have remarkably reduced the severity of risk and consequently detracted the damages and losses incurred on the environment.

  6. Milrinone in advanced heart failure: dose and therapeutic monitor outside intensive care unit.

    Science.gov (United States)

    Charisopoulou, Dafni; Leaver, Neil; Banner, Nicholas R

    2014-04-01

    Advanced chronic heart failure (ACHF) patients often require inotropes before transplantation or ventricular assist device implantation. Milrinone, an inotrope and vasodilator, may accumulate in cardiorenal syndrome with serious adverse effects. We investigated the potential for therapeutic drug monitoring of milrinone levels using High Performance Liquid Chromatography Mass Spectrometry (HPLC-MS). 22 ACHF patients (15 males, 49±9 years) received milrinone 50 µg/kg intravenously (i.v.) during heart catheterization. Milrinone levels were 216±71 ng/ml (within the reported therapeutic range: 100-300 ng/ml), followed by improvements in cardiac index, pulmonary artery and wedge pressures (p milrinone (5-26 days) at 0.1-0.2 µg/kg/min, titrated according to plasma milrinone levels. No adverse events occurred. Therapeutic levels were achieved with doses of 0.2±0.06 µg/Kg/min, below those recommended in Summary of Product Characteristics. Milrinone therapy can be noninvasively monitored by HPLC-MS, while avoiding toxicity in ACHF.

  7. Optimizing Management of Heart Failure by Using Echo and Natriuretic Peptides in the Outpatient Unit.

    Science.gov (United States)

    Dini, Frank Lloyd; Bajraktari, Gani; Zara, Cornelia; Mumoli, Nicola; Rosa, Gian Marco

    2018-01-28

    Chronic heart failure (HF) is an important public health problem and is associated with high morbidity, high mortality, and considerable healthcare costs. More than 90% of hospitalizations due to worsening HF result from elevations of left ventricular (LV) filling pressures and fluid overload, which are often accompanied by the increased synthesis and secretion of natriuretic peptides (NPs). Furthermore, persistently abnormal LV filling pressures and a rise in NP circulating levels are well known indicators of poor prognosis. Frequent office visits with the resulting evaluation and management are most often needed. The growing pressure from hospital readmissions in HF patients is shifting the focus of interest from traditionally symptom-guided care to a more specific patient-centered follow-up care based on clinical findings, BNP and echo. Recent studies supported the value of serial NP measurements and Doppler echocardiographic biomarkers of elevated LV filling pressures as tools to scrutinize patients with impending clinically overt HF. Therefore, combination of echo and pulsed-wave blood-flow and tissue Doppler with NPs appears valuable in guiding ambulatory HF management, since they are potentially useful to distinguish stable patients from those at high risk of decompensation.

  8. Review and evaluation of the Millstone Unit 3 probabilistic safety study. Containment failure modes, radiological source - terms and offsite consequences

    International Nuclear Information System (INIS)

    Khatib-Rahbar, M.; Pratt, W.; Ludewig, H.

    1985-09-01

    A technical review and evaluation of the Millstone Unit 3 probabilistic safety study has been performed. It was determined that; (1) long-term damage indices (latent fatalities, person-rem, etc.) are dominated by late failure of the containment, (2) short-term damage indices (early fatalities, etc.) are dominated by bypass sequences for internally initiated events, while severe seismic sequences can also contribute significantly to early damage indices. These overall estimates of severe accident risk are extremely low compared with other societal sources of risk. Furthermore, the risks for Millstone-3 are comparable to risks from other nuclear plants at high population sites. Seismically induced accidents dominate the severe accident risks at Millstone-3. Potential mitigative features were shown not to be cost-effective for internal events. Value-impact analysis for seismic events showed that a manually actuated containment spray system might be cost-effective

  9. Transformer failure and common-mode loss of instrument power at Nine Mile Point Unit 2 on August 13, 1991

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

    On August 13, 1991, at Nine Mile Point Unit 2 nuclear power plant, located near Scriba, New York, on Lake Ontario, the main transformer experienced an internal failure that resulted in degraded voltage which caused the simultaneous loss of five uninterruptible power supplies, which in turn caused the loss of several nonsafety systems, including reactor control rod position indication, some reactor power and water indication, control room annunciators, the plant communications system, the plant process computer, and lighting at some locations. The reactor was subsequently brought to a safe shutdown. Following this event, the US Nuclear Regulatory Commission dispatched an Incident Investigation Team to the site to determine what happened, to identify the probable causes, and to make appropriate findings and conclusions. This report describes the incident, the methodology used by the team in its investigation, and presents and the team's findings and conclusions. 59 figs., 14 tabs.

  10. Transformer failure and common-mode loss of instrument power at Nine Mile Point Unit 2 on August 13, 1991

    International Nuclear Information System (INIS)

    1991-10-01

    On August 13, 1991, at Nine Mile Point Unit 2 nuclear power plant, located near Scriba, New York, on Lake Ontario, the main transformer experienced an internal failure that resulted in degraded voltage which caused the simultaneous loss of five uninterruptible power supplies, which in turn caused the loss of several nonsafety systems, including reactor control rod position indication, some reactor power and water indication, control room annunciators, the plant communications system, the plant process computer, and lighting at some locations. The reactor was subsequently brought to a safe shutdown. Following this event, the US Nuclear Regulatory Commission dispatched an Incident Investigation Team to the site to determine what happened, to identify the probable causes, and to make appropriate findings and conclusions. This report describes the incident, the methodology used by the team in its investigation, and presents and the team's findings and conclusions. 59 figs., 14 tabs

  11. Failure analysis of cracked head spray piping from the Dresden Unit 2 Boiling Water Reactor

    International Nuclear Information System (INIS)

    Diercks, D.R.; Dragel, G.M.

    1983-07-01

    Several sections of Type 304 stainless steel head spray piping, 6.25 cm (2.5 in.) in diameter, from the Dresden Unit 2 Boiling Water Reactor were examined to determine the nature and causes of coolant leakages detected during hydrostatic tests. Extensive pitting was observed on the outside surface of the piping, and three cracks, all located at a helical stripe apparently rubbed onto the outer surface of the piping, were also noted. Metallographic examination revealed that the cracking had initiated at the outer surface of the pipe, and showed it to be transgranular and highly branched, characteristic of chloride stress corrosion cracking. The surface pitting also appeared to have been caused by chlorides. A scanning electron microprobe x-ray analysis of the corrosion product in the cracks confirmed the presence of chlorides and also indicated the presence of calcium

  12. Step on the gas : Calgary-based firm increases efficiency of compressor fleets

    Energy Technology Data Exchange (ETDEWEB)

    Cope, G.

    2005-11-01

    Many operators are reluctant to run their compressors close to optimum efficiency due to concerns that a frozen well or other problems will push units over their limit, and gas limited areas also cause the machines to be run at partial capacity. This article suggested that the key to compressor optimization lies in the correct identification of deficiencies. Petroleum companies gather thousands of compressor data points every day, ranging from temperature and pressure to control valve position and compressor volume flow, but there is no easy way of analyzing the information. A software prototype called Production Equipment Performance Reporting (PEPR) is capable of disseminating log data and model compressor performance, as well as reporting results for an entire fleet. Raw operating data is gathered for the entire fleet and compressor utilization is ranked to show which compressors are being used efficiently and which ones are lagging. Data is processed from selected points per unit and then divided into key performance indicators (KPI), such as power utilization. To experienced operators, KPIs offer concise information and a range of changes they can make to improve the efficiency of their fleets. It was noted that Devon ran PEPR at one of its major gas fields, and was so satisfied with the results that it has now applied the system to the company's entire fleet. PEPR Inc. was formed in August 2004 to commercially market the production optimization software. In addition to optimizing compressor utilization, the software also handles other important functions, such as asset management, as well as generating downtime reports. While it only takes a day to install the software and a day to train, documenting basic data for each compressor can take several months for a large fleet. It was concluded that PEPR plans to configure its software to other production-related equipment. The system is capable of using operating parameters to calculate emissions instead of

  13. Calculation characteristics of centrifugal compressor operates on a mixture of gases

    Science.gov (United States)

    Novitskiy, B. B.; Arbekov, A. N.

    2016-10-01

    The creation of Closed Brayton Cycle (CBC) unit is impossible without developing the basic knots. This work is devoted to determining the characteristics of a centrifugal compressor when operating at various working bodies with the help of experimental and numerical studies.

  14. Design and Development of an air-cooled Temperature-Swing Adsorption Compressor for Carbon Dioxide

    Science.gov (United States)

    Mulloth, Lila M.

    2003-01-01

    The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. We have a developed a temperature-swing adsorption compressor (TSAC) for performing these tasks that is energy efficient, quiet, and has no wearing parts. This paper discusses the design features of a TSAC hardware that uses air as the cooling medium and has Space Station application.

  15. Performance test for the compressor of 100kW APU

    International Nuclear Information System (INIS)

    Lim, Byeung Jun; Cha, Bong Jun; Yang, Soo Seok; Lee, Kyoung Jin; Baik, Ki Young

    2001-01-01

    The performance test of a centrifugal compressor for APU(Auxiliary Power Unit) which is developed by the collaborative research of KARI and Samsung TechWin has been conducted. The investigated compressor consists of a curved inlet, a centrifugal impeller, a channel diffuser and a plenum chamber. The experiments were carried out in an open-loop centrifugal compressor test rig driven by a turbine. For three different diffusers, overall performance data were obtained at 80%, 90% and 97% of design speed. For the initially designed wedge-type diffuser, test results showed that the compressor was operated at a higher mass flow rate than the design requirement. By reducing the diffuser throat area, the compressor operating range was shifted to lower mass flow rate range. The test result of redesigned wedge-type diffuser showed high pressure loss. To reduce the diffuser loss, diffuser inlet radius was increased and airfoil-type of diffuser was adopted. This airfoil-type diffuser showed reasonal results in terms of design requirement

  16. Orbiting compressor for residential air-conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Jin; Kim, Woo Young; Ahn, Jong Min [Department of Mechanical Engineering, University of Incheon, 12-1 Songdo-dong, Yeonsu-gu, Incheon 406-840 (Korea)

    2010-01-15

    A new type of compressor, called an orbiting compressor, is introduced in this paper. The orbiting compressor is characterized by an orbiting piston, and the piston or orbiter consists of a circular base plate and a ring type vane protruding vertically from the base plate. The orbiter is made to orbit in an annular space formed between two concentric circular walls via an Oldham-ring mechanism, producing two sealed gas pockets on both sides of the vane wrap with a 180 phase difference. This operating mechanism leads to alternating compression and discharge processes, which results in low torque variation. The orbiting compressor has been designed for an R410A residential air conditioner with a cooling capacity of 10.0 kW. The performance of the orbiting compressor model has been analytically investigated, where the volumetric, adiabatic and mechanical efficiencies were calculated to be 94.8%, 90.4% and 93.4%, respectively for the ARI condition. The EER was estimated to be about 10.86 with a motor efficiency of 89%. (author)

  17. Experimental Investigation of Centrifugal Compressor Stabilization Techniques

    Science.gov (United States)

    Skoch, Gary J.

    2003-01-01

    Results from a series of experiments to investigate techniques for extending the stable flow range of a centrifugal compressor are reported. The research was conducted in a high-speed centrifugal compressor at the NASA Glenn Research Center. The stabilizing effect of steadily flowing air-streams injected into the vaneless region of a vane-island diffuser through the shroud surface is described. Parametric variations of injection angle, injection flow rate, number of injectors, injector spacing, and injection versus bleed were investigated for a range of impeller speeds and tip clearances. Both the compressor discharge and an external source were used for the injection air supply. The stabilizing effect of flow obstructions created by tubes that were inserted into the diffuser vaneless space through the shroud was also investigated. Tube immersion into the vaneless space was varied in the flow obstruction experiments. Results from testing done at impeller design speed and tip clearance are presented. Surge margin improved by 1.7 points using injection air that was supplied from within the compressor. Externally supplied injection air was used to return the compressor to stable operation after being throttled into surge. The tubes, which were capped to prevent mass flux, provided 9.3 points of additional surge margin over the baseline surge margin of 11.7 points.

  18. Identifying lubricant options for compressor bearing designs

    Science.gov (United States)

    Karnaz, J.; Seeton, C.; Dixon, L.

    2017-08-01

    Today’s refrigeration and air conditioning market is not only driven by the environmental aspects of the refrigerants, but also by the energy efficiency and reliability of system operation. Numerous types of compressor designs are used in refrigeration and air conditioning applications which means that different bearings are used; and in some cases, multiple bearing types within a single compressor. Since only one lubricant is used, it is important to try to optimize the lubricant to meet the various demands and requirements for operation. This optimization entails investigating different types of lubricant chemistries, viscosities, and various formulation options. What makes evaluating these options more challenging is the refrigerant which changes the properties of the lubricant delivered to the bearing. Once the lubricant and refrigerant interaction are understood, through various test methods, then work can start on collaborating with compressor engineers on identifying the lubricant chemistry and formulation options. These interaction properties are important to the design engineer to make decisions on the adequacy of the lubricant before compressor tests are started. This paper will discuss the process to evaluate lubricants for various types of compressors and bearing design with focus on what’s needed for current refrigerant trends. In addition, the paper will show how the lubricant chemistry choice can be manipulated through understanding of the bearing design and knowledge of interaction with the refrigerant to maximize performance. Emphasis will be placed on evaluation of synthetic lubricants for both natural and synthetic low GWP refrigerants.

  19. Compressor Surge Control Design Using Linear Matrix Inequality Approach

    OpenAIRE

    Uddin, Nur; Gravdahl, Jan Tommy

    2017-01-01

    A novel design for active compressor surge control system (ASCS) using linear matrix inequality (LMI) approach is presented and including a case study on piston-actuated active compressor surge control system (PAASCS). The non-linear system dynamics of the PAASCS is transformed into linear parameter varying (LPV) system dynamics. The system parameters are varying as a function of the compressor performance curve slope. A compressor surge stabilization problem is then formulated as a LMI probl...

  20. Kinetics of a gas adsorption compressor

    International Nuclear Information System (INIS)

    Chan, C.K.; Elleman, D.D.; Tward, E.

    1984-01-01

    This chapter uses a two-phase model to analyze the transients of a gas adsorption compressor. The modeling of the adsorption process is based on complete thermal and mechanical equilibrium between the gaseous phase and the adsorbed gas phase. The theories and techniques that have been developed for a two-phase system are used to predict the pressure, the temperature and the mass flow transients in a gas sorption compressor. The analytical solutions are then compared with the performance of a laboratory gas adsorption compressor. A computer code was written to solve the governing equations, using a standard forward marching predictor-corrector method. It is found that while the analytical model overpredicts the pressure and the temperature transient, it predicts the general trend of the transient profile and the existence of the turning point

  1. Sorption compressor/mechanical expander hybrid refrigeration

    Science.gov (United States)

    Jones, J. A.; Britcliffe, M.

    1987-01-01

    Experience with Deep Space Network (DSN) ground-based cryogenic refrigerators has proved the reliability of the basic two-stage Gifford-McMahon helium refrigerator. A very long life cryogenic refrigeration system appears possible by combining this expansion system or a turbo expansion system with a hydride sorption compressor in place of the usual motor driven piston compressor. To test the feasibility of this system, a commercial Gifford-McMahon refrigerator was tested using hydrogen gas as the working fluid. Although no attempt was made to optimize the system for hydrogen operation, the refrigerator developed 1.3 W at 30 K and 6.6 W at 60 K. The results of the test and of theoretical performances of the hybrid compressor coupled to these expansion systems are presented.

  2. Compressor airfoil tip clearance optimization system

    Science.gov (United States)

    Little, David A.; Pu, Zhengxiang

    2015-08-18

    A compressor airfoil tip clearance optimization system for reducing a gap between a tip of a compressor airfoil and a radially adjacent component of a turbine engine is disclosed. The turbine engine may include ID and OD flowpath boundaries configured to minimize compressor airfoil tip clearances during turbine engine operation in cooperation with one or more clearance reduction systems that are configured to move the rotor assembly axially to reduce tip clearance. The configurations of the ID and OD flowpath boundaries enhance the effectiveness of the axial movement of the rotor assembly, which includes movement of the ID flowpath boundary. During operation of the turbine engine, the rotor assembly may be moved axially to increase the efficiency of the turbine engine.

  3. Cold Climate Heat Pumps Using Tandem Compressors

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [ORNL; Abdelaziz, Omar [ORNL; Rice, C Keith [ORNL; Baxter, Van D [ORNL

    2016-01-01

    In cold climate zones, e.g. ASHRAE climate regions IV and V, conventional electric air-source heat pumps (ASHP) do not work well, due to high compressor discharge temperatures, large pressure ratios and inadequate heating capacities at low ambient temperatures. Consequently, significant use of auxiliary strip heating is required to meet the building heating load. We introduce innovative ASHP technologies as part of continuing efforts to eliminate auxiliary strip heat use and maximize heating COP with acceptable cost-effectiveness and reliability. These innovative ASHP were developed using tandem compressors, which are capable of augmenting heating capacity at low temperatures and maintain superior part-load operation efficiency at moderate temperatures. Two options of tandem compressors were studied; the first employs two identical, single-speed compressors, and the second employs two identical, vapor-injection compressors. The investigations were based on system modeling and laboratory evaluation. Both designs have successfully met the performance criteria. Laboratory evaluation showed that the tandem, single-speed compressor ASHP system is able to achieve heating COP = 4.2 at 47 F (8.3 C), COP = 2.9 at 17 F (-8.3 C), and 76% rated capacity and COP = 1.9 at -13 F (-25 C). This yields a HSPF = 11.0 (per AHRI 210/240). The tandem, vapor-injection ASHP is able to reach heating COP = 4.4 at 47 F, COP = 3.1 at 17 F, and 88% rated capacity and COP = 2.0 at -13 F. This yields a HSPF = 12.0. The system modeling and further laboratory evaluation are presented in the paper.

  4. 49 CFR 178.337-15 - Pumps and compressors.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pumps and compressors. 178.337-15 Section 178.337... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.337-15 Pumps and compressors. (a) Liquid pumps or gas compressors, if used, must be of suitable design, adequately protected...

  5. 49 CFR 178.338-17 - Pumps and compressors.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pumps and compressors. 178.338-17 Section 178.338... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.338-17 Pumps and compressors. (a) Liquid pumps and gas compressors, if used, must be of suitable design, adequately protected...

  6. [Ten-year evolution of mechanical ventilation in acute respiratory failure in the hematogical patient admitted to the intensive care unit].

    Science.gov (United States)

    Belenguer-Muncharaz, A; Albert-Rodrigo, L; Ferrandiz-Sellés, A; Cebrián-Graullera, G

    2013-10-01

    A comparison was made between invasive mechanical ventilation (IMV) and noninvasive positive pressure ventilation (NPPV) in haematological patients with acute respiratory failure. A retrospective observational study was made from 2001 to December 2011. A clinical-surgical intensive care unit (ICU) in a tertiary hospital. Patients with hematological malignancies suffering acute respiratory failure (ARF) and requiring mechanical ventilation in the form of either IMV or NPPV. Analysis of infection and organ failure rates, duration of mechanical ventilation and ICU and hospital stays, as well as ICU, hospital and mortality after 90 days. The same variables were analyzed in the comparison between NPPV success and failure. Forty-one patients were included, of which 35 required IMV and 6 NPPV. ICU mortality was higher in the IMV group (100% vs 37% in NPPV, P=.006). The intubation rate in NPPV was 40%. Compared with successful NPPV, failure in the NPPV group involved more complications, a longer duration of mechanical ventilation and ICU stay, and greater ICU and hospital mortality. Multivariate analysis of mortality in the NPPV group identified NPPV failure (OR 13 [95%CI 1.33-77.96], P=.008) and progression to acute respiratory distress syndrome (OR 10 [95%CI 1.95-89.22], P=.03) as prognostic factors. The use of NPPV reduced mortality compared with IMV. NPPV failure was associated with more complications. Copyright © 2012 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  7. Positive predictive value and impact of misdiagnosis of a heart failure diagnosis in administrative registers among patients admitted to a University Hospital cardiac care unit

    DEFF Research Database (Denmark)

    Mard, Shan; Nielsen, Finn Erland

    2010-01-01

    OBJECTIVE: To evaluate the positive predictive value (PPV) of a diagnosis of heart failure (HF) in the Danish National Registry of Patients (NRP) among patients admitted to a University Hospital cardiac care unit, and to evaluate the impact of misdiagnosing HF. DESIGN: The NRP was used to identify...

  8. Centrifugal compressor design options for small turbochargers

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, C. [ITC, San Diego (United States)

    1998-07-01

    Evolutionary development of the small turbocharger centrifugal compressor over the past four decades has resulted in a finely honed turbomachinery component satisfying both thermodynamic and economic constraints. At this penultimate stage of development an appraisal was considered timely of the remaining design options that exist to enhance the performance characteristics and cost reduction features. This paper presents the results of an analytical study of various small centrifugal compressor design options, assessed in merit of both aerodynamic and manufacturing cost attributes, together with recommendations for future research avenues. (author)

  9. Low-temperature centrifugal helium compressor

    International Nuclear Information System (INIS)

    Kawada, M.; Togo, S.; Akiyama, Y.; Wada, R.

    1974-01-01

    A centrifugal helium compressor with gas bearings, which can be operated at the temperature of liquid nitrogen, has been investigated. This compressor has the advantages that the compression ratio should be higher than the room temperature operation and that the contamination of helium could be eliminated. The outer diameter of the rotor is 112 mm. The experimental result for helium gas at low temperature shows a flow rate of 47 g/s and a compression ratio of 1.2 when the inlet pressure was 1 ata and the rotational speed 550 rev/s. The investigation is now focused on obtaining a compression ratio of 1.5. (author)

  10. Routine Ultrasound Quality Assurance in a Multi-Unit Radiology Department: A Retrospective Evaluation of Transducer Failures.

    Science.gov (United States)

    Vitikainen, Anne-Mari; Peltonen, Juha I; Vartiainen, Eija

    2017-09-01

    The importance of quality assurance (QA) in medical ultrasound (US) has been widely recognized and recommendations concerning technical QA have been published over the years. However, the demonstrated impact of a properly working QA protocol on clinical routine has been scarce. We investigated the transducer write-off causes for a 5-y period in a multi-unit radiology department with an annual average of 230 transducers in demanding diagnostic use. The transducer faults and the initial observers of the faults leading to transducer write-offs were traced and categorized. The most common cause of transducer write-off was an image uniformity problem or element failure. Mechanical faults or excessive leakage current and defects in the lens constituted smaller yet substantial shares. Our results suggest that a properly working routine QA program can detect majority of the faults before they are reported by users. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  11. Intensive symptom control of opioid-refractory dyspnea in congestive heart failure: Role of milrinone in the palliative care unit.

    Science.gov (United States)

    Silvestre, Julio; Montoya, Maria; Bruera, Eduardo; Elsayem, Ahmed

    2015-12-01

    We describe an exemplary case of congestive heart failure (CHF) symptoms controlled with milrinone. We also analyze the benefits and risks of milrinone administration in an unmonitored setting. We describe the case of a patient with refractory leukemia and end-stage CHF who developed severe dyspnea after discontinuation of milrinone. At that point, despite starting opioids, she had been severely dyspneic and anxious, requiring admission to the palliative care unit (PCU) for symptom control. After negotiation with hospital administrators, milrinone was administered in an unmonitored setting such as the PCU. A multidisciplinary team approach was also provided. Milrinone produced a dramatic improvement in the patient's symptom scores and performance status. The patient was eventually discharged to home hospice on a milrinone infusion with excellent symptom control. This case suggests that milrinone may be of benefit for short-term inpatient administration for dyspnea management, even in unmonitored settings and consequently during hospice in do-not-resuscitate (DNR) patients. This strategy may reduce costs and readmissions to the hospital related to end-stage CHF.

  12. Compressor Foundation Analysis Tool(COFANTO)

    NARCIS (Netherlands)

    Eijk, A.; Lentzen, S.S.K; Zuada Coelho, B.E.; Galanti, F.M.B.

    2012-01-01

    Reciprocating compressors are generally supported on a heavy concrete foundation. In spite of the large inertia and stiffness of the foundation, problems can occur due to interaction between the mechanical installation and the foundation. Two types of problems may occur. In the first type, the

  13. Computational analysis of a multistage axial compressor

    Science.gov (United States)

    Mamidoju, Chaithanya

    Turbomachines are used extensively in Aerospace, Power Generation, and Oil & Gas Industries. Efficiency of these machines is often an important factor and has led to the continuous effort to improve the design to achieve better efficiency. The axial flow compressor is a major component in a gas turbine with the turbine's overall performance depending strongly on compressor performance. Traditional analysis of axial compressors involves throughflow calculations, isolated blade passage analysis, Quasi-3D blade-to-blade analysis, single-stage (rotor-stator) analysis, and multi-stage analysis involving larger design cycles. In the current study, the detailed flow through a 15 stage axial compressor is analyzed using a 3-D Navier Stokes CFD solver in a parallel computing environment. Methodology is described for steady state (frozen rotor stator) analysis of one blade passage per component. Various effects such as mesh type and density, boundary conditions, tip clearance and numerical issues such as turbulence model choice, advection model choice, and parallel processing performance are analyzed. A high sensitivity of the predictions to the above was found. Physical explanation to the flow features observed in the computational study are given. The total pressure rise verses mass flow rate was computed.

  14. Energy saving screw compressor technology; Energiebesparende schroefcompressortechnologie

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, A. [RefComp, Lonigo (Italy); Neus, M. [Delta Technics Engineering, Breda (Netherlands)

    2011-03-15

    Smart solutions to reduce the energy consumption are continuously part of investigation in the refrigeration technology. This article subscribed the technology on which way energy can be saved at the operation of screw compressors which are used in air conditioners and refrigerating machinery. The combination of frequency control and Vi-control (intrinsic volumetric ratio) such as researched in the laboratory of RefComp is for the user attractive because the energy efficiency during part load operation is much better. Smart uses of thermodynamics, electric technology and electronic control are the basics of these applications. According to the manufacturer's information it is possible with these new generation screw compressors to save approx. 26% energy in comparison with the standard screw compressor. [Dutch] In dit artikel wordt de technologie omschreven waarmee veel energie bespaard kan worden bij schroefcompressoren die worden gebruikt in airconditioningsystemen en koel- en vriesinstallaties. De combinatie van frequentieregeling en Vi- regeling (Vi is de intrinsieke volumetrische verhouding) zoals onderzocht in het laboratorium van RefComp biedt de gebruiker veel voordelen doordat de energie-efficintie van de compressor tijdens deellast enorm wordt verbeterd. Slim gebruik van thermodynamika, elektrotechniek en elektronica vormen de basis van deze toepassing. Volgens de fabrikant kan met deze nieuwe generatie schroefcompressoren circa 26 procent op het energiegebruik tijdens deellast worden bespaard in vergelijking met de standaard serie schroefcompressoren.

  15. Energy saving potential in existing industrial compressors

    International Nuclear Information System (INIS)

    Vittorini, Diego; Cipollone, Roberto

    2016-01-01

    The Compressed Air Sector accounts for a mean 10% worldwide electricity consumption, which ensures about its importance, when energy saving and CO_2 emissions reduction are in question. Since the compressors alone account for 15% overall industry electricity consumption, it appears vital to pay attention to machine performances. The paper presents an overview of present compressor technology and focuses on saving directions for screw and sliding vanes machines, according to data provided by the Compressed Air and Gas Institute and PNEUROP. Data were processed to obtain consistency with fixed reference pressures and organized as a function of main operating parameters. Each sub-term, contributing to the overall efficiency (adiabatic, volumetric, mechanical, electric, organic), was considered separately: the analysis showed that the thermodynamic improvement during compression achievable by splitting the compression in two stages, with a lower compression ratio, opens the way to significantly reduce the energy specific consumption. - Highlights: • Compressors technology overview in industrial compressed air systems. • Market compressors efficiency baseline definition. • Energy breakdown and evaluation of main efficiency terms. • Assessment of air cooling-related energy saving potential. • Energy specific consumption reduction through dual stage compression.

  16. Composite hub/metal blade compressor rotor

    Science.gov (United States)

    Yao, S.

    1978-01-01

    A low cost compressor rotor was designed and fabricated for a small jet engine. The rotor hub and blade keepers were compression molded with graphite epoxy. Each pair of metallic blades was held in the hub by a keeper. All keepers were locked in the hub with circumferential windings. Feasibility of fabrication was demonstrated in this program.

  17. Positive feedback stabilization of centrifugal compressor surge

    NARCIS (Netherlands)

    Willems, Frank; Heemels, W.P.M.H.; de Jager, Bram; Stoorvogel, Antonie Arij

    Stable operation of axial and centrifugal compressors is limited towards low mass flows due to the occurrence of surge. The stable operating region can be enlarged by active control. In this study, we use a control valve which is fully closed in the desired operating point and only opens to

  18. Positive feedback stabilization of centrifugal compressor surge

    NARCIS (Netherlands)

    Willems, F.P.T.; Heemels, W.P.M.H.; Jager, de A.G.; Stoorvogel, A.A.

    2002-01-01

    Stable operation of axial and centrifugal compressors is limited towards low mass flows due to the occurrence of surge. The stable operating region can be enlarged by active control. In this study, we use a control valve which is fully closed in the desired operating point and only opens to

  19. Centrifugal compressor tip clearance and impeller flow

    Energy Technology Data Exchange (ETDEWEB)

    Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari [Laboratory of Fluid Dynamics, LUT School of Energy Systems, Lappeenranta University of Technology, Lappeenranta (Finland); Engeda, Abraham [Turbomachinery Laboratory, Dept. of Mechanical Engineering, Michigan State University, East Lansing (United States)

    2016-11-15

    Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease.

  20. Centrifugal compressor tip clearance and impeller flow

    International Nuclear Information System (INIS)

    Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari; Engeda, Abraham

    2016-01-01

    Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease

  1. Configuration and testing of a saturated vapor helium compressor

    International Nuclear Information System (INIS)

    Ludwigsen, J.L.; Iwasa, Y.; Smith, J.L.

    1986-01-01

    A saturated vapor helium compressor was designed and tested as a component of a helium-temperature refrigeration cycle. The use of the cold compressor allows reduction of both the precooling heat exchanger area and main compressor size compared to a conventional cycle due to increased pressure of the return gas. The compressor tested was a single-piston reciprocating device which was controlled with programmable hydraulic/pneumatic logic. The compressor was mounted at the cold end of a CTI Model 1400 helium liquefier. An average compression ratio of 2.4 was obtained and an average efficiency of 82% was achieved. In computing compressor efficiency, external heat leaks to the compressor were neglected

  2. Fault detection and diagnosis for refrigerator from compressor sensor

    Science.gov (United States)

    Keres, Stephen L.; Gomes, Alberto Regio; Litch, Andrew D.

    2016-12-06

    A refrigerator, a sealed refrigerant system, and method are provided where the refrigerator includes at least a refrigerated compartment and a sealed refrigerant system including an evaporator, a compressor, a condenser, a controller, an evaporator fan, and a condenser fan. The method includes monitoring a frequency of the compressor, and identifying a fault condition in the at least one component of the refrigerant sealed system in response to the compressor frequency. The method may further comprise calculating a compressor frequency rate based upon the rate of change of the compressor frequency, wherein a fault in the condenser fan is identified if the compressor frequency rate is positive and exceeds a condenser fan fault threshold rate, and wherein a fault in the evaporator fan is identified if the compressor frequency rate is negative and exceeds an evaporator fan fault threshold rate.

  3. Development of a Committee of Artificial Neural Networks for the Performance Testing of Compressors for Thermal Machines in Very Reduced Times

    Directory of Open Access Journals (Sweden)

    Coral Rodrigo

    2015-03-01

    Full Text Available This paper presents a new test method able to infer - in periods of less than 7 seconds - the refrigeration capacity of a compressor used in thermal machines, which represents a time reduction of approximately 99.95% related to the standardized traditional methods. The method was developed aiming at its application on compressor manufacture lines and on 100% of the units produced. Artificial neural networks (ANNs were used to establish a model able to infer the refrigeration capacity based on the data collected directly on the production line. The proposed method does not make use of refrigeration systems and also does not require using the compressor oil.

  4. Acute renal failure requiring renal replacement therapy in the intensive care unit: impact on prognostic assessment for shared decision making.

    Science.gov (United States)

    Johnson, Robert F; Gustin, Jillian

    2011-07-01

    A 69-year-old female was receiving renal replacement therapy (RRT) for acute renal failure (ARF) in an intensive care unit (ICU). Consultation was requested from the palliative medicine service to facilitate a shared decision-making process regarding goals of care. Clinician responsibility in shared decision making includes the formulation and expression of a prognostic assessment providing the necessary perspective for a spokesperson to match patient values with treatment options. For this patient, ARF requiring RRT in the ICU was used as a focal point for preparing a prognostic assessment. A prognostic assessment should include the outcomes of most importance to a discussion of goals of care: mortality risk and survivor functional status, in this case including renal recovery. A systematic review of the literature was conducted to document published data regarding these outcomes for adult patients receiving RRT for ARF in the ICU. Forty-one studies met the inclusion criteria. The combined mean values for short-term mortality, long-term mortality, renal-function recovery of short-term survivors, and renal-function recovery of long-term survivors were 51.7%, 68.6%, 82.0%, and 88.4%, respectively. This case example illustrates a process for formulating and expressing a prognostic assessment for an ICU patient requiring RRT for ARF. Data from the literature review provide baseline information that requires adjustment to reflect specific patient circumstances. The nature of the acute primary process, comorbidities, and severity of illness are key modifiers. Finally, the prognostic assessment is expressed during a family meeting using recommended principles of communication.

  5. Characteristics and in-hospital outcomes of patients with acute coronary syndromes and heart failure in the United Arab Emirates.

    Science.gov (United States)

    Shehab, Abdulla; Al-Dabbagh, Bayan; Almahmeed, Wael; Bustani, Nazar; Nagelkerke, Nicolaas; Yusufali, Afzal; Wassef, Adel; Ibrahim, Mohamed; Brek, Azan Bin

    2012-09-26

    Heart failure (HF) is a serious complication of acute coronary syndromes (ACS), and is associated with high in-hospital mortality and poor long-term survival. The aims of this study were to describe the clinical characteristics, management and in-hospital outcomes of coronary syndrome (ACS) patients with HF in the United Arab Emirates. The study was selected from the Gulf Registry of Acute Coronary Events (Gulf RACE), a prospective multi-national, multicenter registry of patients hospitalized with ACS in six Middle East countries. The present analysis was focused on participants admitted to various hospitals in the UAE with a diagnosis of ACS in 2007 and were analyzed in terms of HF (Killip class II/III and IV) on admission. Of 1691 patients (mean age: 52.6 ± 11.7 years; 210 Females, 1481 Males) with ACS, 356 (21%) had an admission diagnosis of HF (Killip class II/III and IV). HF patients were less frequently males (19.2% vs. 34.3%; P < 0.001). HF was more frequently associated with hypertension (64.3% vs. 43.9%; P < 0.001), hyperlipidemia (49.4% vs. 31.8%; P < 0.001) and diabetes mellitus (DM) (51.1% vs. 36.2%; P < 0.001). HF was significantly associated with in-hospital mortality (OR = 11.821; 95% CI: 5.385-25.948; P < 0.001). In multivariate logistic regression, age, hyperlipidemia, heart rate and DM were associated with higher in-hospital HF. HF is observed in about 1 in 5 patients with ACS in the UAE and is associated with a significant increase in in-hospital mortality and other adverse outcomes.

  6. Automatic pumpdown of the 2K cold compressors for the CEBAF central helium liquefier

    International Nuclear Information System (INIS)

    Bevins, B.S.; Chronis, W.C.; Keesee, M.S.

    1996-01-01

    The 2K system at CEBAF includes four stages of centrifugal cold compressors that operate between a suction pressure of 0.031 atm and a discharge of ∼1 atm. Starting the cold compressors and pumping the system down to operating pressure is a complex and time consuming operation. Many months of rigorous testing were required to develop a reliable startup procedure. This procedure has been automated through the development of an Autopumpdown program that intelligently coordinates the necessary steps across the boundaries of the existing cryogenic and accelerator control systems. this program has greatly reduced both the time and effort required to recover from failures and restart the system. The paper describes the requirements addressed by the program, the steps it takes while operating, the historical development of the program, the spin-off benefits, and the course of anticipated future developments

  7. Automatic pumpdown of the 2K cold compressors for the CEBAF central helium liquefier

    International Nuclear Information System (INIS)

    Bevins, B.S.; Chronis, W.C.; Keesee, M.S.

    1996-01-01

    The 2K system at CEBAF includes four stages of centrifugal cold compressors that operate between a suction pressure of 0.031 atm and a discharge of ∼1 atm. Starting the cold compressors and pumping the system down to operating pressure is a complex and time consuming operation. Many months of rigorous testing were required to develop a reliable startup procedure. This procedure has been automated through the development of an Autopumpdown program that intelligently coordinates the necessary steps across the boundaries of the existing cryogenic and accelerator control systems. This program has greatly reduced both the time and effort required to recover from failures and restart the system. The paper describes the requirements addressed by the program, the steps it takes while operating, the historical development of the program, the spin-off benefits, and the course of anticipated future developments

  8. Operation Test of the Supercritical CO{sub 2} Compressor Supported with Active Magnetic Bearing

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jae Eun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, Seong Kuk; Lee, Jeong IK [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    In this paper, the operation test status of the SCIEL sCO{sub 2} AMB Compressor is briefly described. The Supercritical CO{sub 2} Brayton Cycle Integral Experiment Loop (SCIEL) has been installed in Korea Atomic Energy Research Institute (KAERI) to develop the element technologies for the sCO{sub 2} cycle power generation system. The operation of the SCIEL has mainly focused on sCO{sub 2} compressor development and establishing sCO{sub 2} system control logic. The installation of the SCIEL low compression loop was finished in December 2014 and research team succeeded in generating electric power on the supercritical state of the CO{sub 2} in May 2015. The SCIEL has been built in KAERI to develop the element technologies and the system control logics for the sCO{sub 2} cycle power conversion unit of the next generation reactor. For the stable operation of the sCO{sub 2} compressor under high rotational speed, the AMB sCO{sub 2} compressor was developed and achieved the maximum 40,000 rpm.

  9. Nitric oxide-to-nitrogen dioxide conversion rates at a natural gas compressor station

    International Nuclear Information System (INIS)

    Gibbons, T.H.; Gebhart, D.H.

    1992-01-01

    An ambient air quality measurements program collected NO x data for a year at a natural gas compressor station located in the southwestern United States. This monitoring program had the unique characteristic of measuring ambient NO x concentrations at a remote location that was virtually free of NO sources other than the compressor station. These measurements indicate that the only source of NO x emissions in the area comes from the combustion of natural gas by the compressor station turbines. Thus, increases in NO 2 calculation of NO-to-NO 2 conversion rates. These results indicate 22 percent of the compressor station NO x emissions were converted to NO 2 in the near field. Regulatory modeling methods often assume that all NO x emissions exist as NO 2 . In an environment where ozone concentrations are relatively low, however, NO 2 concentrations are commonly calculated using the ozone limiting method (OLM), wherein NO conversion to NO 2 is limited by the amount of ozone present. Results from the measurement program show that the OLM generally overpredicts NO 2 concentrations in the near field. A partial conversion method is more suitable for predicting NO 2 concentrations for low-level natural gas combustion sources

  10. Modelling and measurement of a moving magnet linear compressor performance

    International Nuclear Information System (INIS)

    Liang, Kun; Stone, Richard; Davies, Gareth; Dadd, Mike; Bailey, Paul

    2014-01-01

    A novel moving magnet linear compressor with clearance seals and flexure bearings has been designed and constructed. It is suitable for a refrigeration system with a compact heat exchanger, such as would be needed for CPU cooling. The performance of the compressor has been experimentally evaluated with nitrogen and a mathematical model has been developed to evaluate the performance of the linear compressor. The results from the compressor model and the measurements have been compared in terms of cylinder pressure, the ‘P–V’ loop, stroke, mass flow rate and shaft power. The cylinder pressure was not measured directly but was derived from the compressor dynamics and the motor magnetic force characteristics. The comparisons indicate that the compressor model is well validated and can be used to study the performance of this type of compressor, to help with design optimization and the identification of key parameters affecting the system transients. The electrical and thermodynamic losses were also investigated, particularly for the design point (stroke of 13 mm and pressure ratio of 3.0), since a full understanding of these can lead to an increase in compressor efficiency. - Highlights: • Model predictions of the performance of a novel moving magnet linear compressor. • Prototype linear compressor performance measurements using nitrogen. • Reconstruction of P–V loops using a model of the dynamics and electromagnetics. • Close agreement between the model and measurements for the P–V loops. • The design point motor efficiency was 74%, with potential improvements identified

  11. The results of pre-design studies on the development of a new design of gas turbine compressor package of GPA-C-16 type

    Science.gov (United States)

    Smirnov, A. V.; Chobenko, V. M.; Shcherbakov, O. M.; Ushakov, S. M.; Parafiynyk, V. P.; Sereda, R. M.

    2017-08-01

    The article summarizes the results of analysis of data concerning the operation of turbocompressor packages at compressor stations for the natural gas transmission system of Ukraine. The basic requirements for gas turbine compressor packages used for modernization and reconstruction of compressor stations are considered. Using a 16 MW gas turbine package GPA-C-16S/76-1,44M1 as an example, the results of pre-design studies and some technical solutions that improve the energy efficiency of gas turbine compressor packages and their reliability, as well as its environmental performance are given. In particular, the article deals with the matching of performance characteristics of a centrifugal compressor (hereinafter compressor) and gas turbine drive to reduce fuel gas consumption; as well as application of energy efficient technologies, in particular, exhaust gas heat recovery units and gas-oil heat exchangers in turbocompressor packages oil system; as well as reducing emissions of carbon monoxide into the atmosphere using a catalytic exhaust system. Described technical solutions can be used for development of other types of gas turbine compressor packages.

  12. A recursive framework for time-dependent characteristics of tested and maintained standby units with arbitrary distributions for failures and repairs

    International Nuclear Information System (INIS)

    Vaurio, Jussi K.

    2015-01-01

    The time-dependent unavailability and the failure and repair intensities of periodically tested aging standby system components are solved with recursive equations under three categories of testing and repair policies. In these policies, tests or repairs or both can be minimal or perfect renewals. Arbitrary distributions are allowed to times to failure as well as to repair and renewal durations. Major preventive maintenance is done periodically or at random times, e.g. when a true demand occurs. In the third option process renewal is done if a true demand occurs or when a certain mission time has expired since the previous maintenance, whichever occurs first. A practical feature is that even if a repair can renew the unit, it does not generally renew the alternating process. The formalism updates and extends earlier results by using a special backward-renewal equation method, by allowing scheduled tests not limited to equal intervals and accepting arbitrary distributions and multiple failure types and causes, including failures caused by tests, human errors and true demands. Explicit solutions are produced to integral equations associated with an age-renewal maintenance policy. - Highlights: • Time-dependent unavailability, failure count and repair count for a standby system. • Free testing schedule and distributions for times to failure, repair and maintenance. • Multiple failure modes; tests or repairs or both can be minimal or perfect renewals. • Process renewals periodically, randomly or based on the process age or an initiator. • Backward renewal equations as explicit solutions to Volterra-type integral equations

  13. Serum 1H-NMR metabolomic fingerprints of acute-on-chronic liver failure in intensive care unit patients with alcoholic cirrhosis.

    Directory of Open Access Journals (Sweden)

    Roland Amathieu

    Full Text Available INTRODUCTION: Acute-on-chronic liver failure is characterized by acute deterioration of liver function in patients with compensated or decompensated, but stable, cirrhosis. However, there is no accurate definition of acute-on-chronic liver failure and physicians often use this term to describe different clinical entities. Metabolomics investigates metabolic changes in biological systems and identifies the biomarkers or metabolic profiles. Our study assessed the metabolomic profile of serum using proton nuclear magnetic resonance ((1H-NMR spectroscopy to identify metabolic changes related to acute-on-chronic liver failure. PATIENTS: Ninety-three patients with compensated or decompensated cirrhosis (CLF group but stable liver function and 30 patients with cirrhosis and hospitalized for the management of an acute event who may be responsible of acute-on-chronic liver failure (ACLF group, were fully analyzed. Blood samples were drawn at admission, and sera were separated and stored at -80°C until (1H-NMR spectral analysis. Using orthogonal projection to latent-structure discriminant analyses, various metabolites contribute to the complete separation between these both groups. RESULTS: The predictability of the model was 0.73 (Q(2 Y and the explained variance was 0.63 (R(2 Y. The main metabolites that had increased signals related to acute-on-chronic liver failure were lactate, pyruvate, ketone bodies, glutamine, phenylalanine, tyrosine, and creatinine. High-density lipids were lower in the ALCF group than in CLF group. CONCLUSION: A serum metabolite fingerprint for acute-on-chronic liver failure, obtained with (1H-NMR, was identified. Metabolomic profiling may aid clinical evaluation of patients with cirrhosis admitted into intensive care units with acute-on-chronic liver failure, and provide new insights into the metabolic processes involved in acute impairment of hepatic function.

  14. Incidence of the acute renal failure in the intensive care unit at the General Hospital of Mexico: Risk factors and associated morbidity and mortality

    OpenAIRE

    Herrera-Méndez, J.; Sánchez-Velázquez, L.D.; González-Chávez, A.; Rodríguez-Terán, G.

    2015-01-01

    Background: The acute renal failure (ARF) contributes to a longer hospital stay, morbidity, mortality and use of resources in critical patients. The estimate of its incidence was difficult, mainly due to the lack of a generally accepted definition. Objective: To determine the incidence, risk factors and effects of the ARF in critical patients. Material and methods: Study of prospective cohort. Patients hospitalised in the Intensive Care Unit (ICU) were included. The population was di...

  15. Numerical Simulation and Experimental Study on Temperature Distribution of Self-Lubricating Packing Rings in Reciprocating Compressors

    Directory of Open Access Journals (Sweden)

    Jia Xiaohan

    2016-01-01

    Full Text Available The nonuniform abrasion failure and high-temperature thermal failure of packing rings have a significant influence on compressor reliability, particularly that of oil-free compressors. In this study, a test rig was constructed to measure the dynamic temperature of packing rings under different operational conditions in an oil-free reciprocating compressor. The dynamic axial and radial temperature distributions of the packing rings were obtained using an innovative internal temperature testing device that kept the thermocouples and packing box relatively static during compressor operation. A three-dimensional heat transfer model was also developed to analyze the temperature distribution of the packing boxes, piston rod, and cylinder during such operation. Good agreement was observed between the simulation results and experimental data, which showed an average relative error of less than 2.35%. The results indicate that the pressure ratio exerts a significant effect on the axial temperature distribution and determines which packing ring reaches the maximum temperature. They also show the average temperature to rise with an increase in the rotational speed and to fall with an improvement in the external cooling conditions. Finally, the material of the packing rings was found to affect the temperature gradient from their inner to outer surface.

  16. Compressor blade setting angle accuracy study, volume 1

    Science.gov (United States)

    Holman, F. F.; Kidwell, J. R.

    1976-01-01

    The aerodynamic test of a small, single stage, highly loaded, axial flow transonic compressor is covered. The stage was modified by fabricating a 24 blade rotor with mis-set blades in a repeating pattern - two degrees closed from nominal, two degrees open from nominal and nominal. The unit was instrumented to determine overall performance and average blade element data. High-response, dynamic pressure probes were installed to record pressure patterns at selected points in the flowpath. Testing was conducted at speeds from 70 to 94% of design equivalent speed with a conventional casing and also with circumferential grooves over the rotor tip. Testing indicated severe performance penalties were incurred as a result of the mis-set blading. Lower flow, pressure ratio, and efficiency were observed for the stage with or without casing treatment. Periodic pressure variations were detected at every location where high response pressure sensors were located and were directly related to blading geometry.

  17. Operational Experience with a Cryogenic Axial-Centrifugal Compressor

    CERN Document Server

    Decker, L; Löhlein, K; Purtschert, W; Ziegler, B L; Lebrun, P; Tavian, L; Brunovsky, I; Tucek, L

    1998-01-01

    The Large Hadron Collider (LHC), presently under construction at CERN, requires large refrigeration capacity at 1.8 K. Compression of gaseous helium at cryogenic temperatures is therefore inevitable. Together with subcontractors, Linde Kryotechnik has developed a prototype machine. This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating at ambient temperature. Integrated in a test facility for superconducting magnets the machine has been commissioned without major problems and successfully gone through the acceptance test in autumn 1995. Subsequent steps were initiated to improve efficiency of this prototype. This paper describes operating experience gained so far and reports on measured performance prior to and after constructional modifications.

  18. Modification of a compressor performance test bench for liquid slugging observation in refrigeration compressors

    Science.gov (United States)

    Ola, Max; Thomas, Christiane; Hesse, Ullrich

    2017-08-01

    Compressor performance test procedures are defined by the standard DIN EN 13771, wherein a variety of possible calorimeter and flow rate measurement methods are suggested. One option is the selection of two independent measurement methods. The accuracies of both selected measurement methods are essential. The second option requires only one method. However the measurement accuracy of the used device has to be verified and recalibrated on a regular basis. The compressor performance test facility at the Technische Universitaet Dresden uses a calibrated flow measurement sensor, a hot gas bypass and a mixed flow heat exchanger. The test bench can easily be modified for tests of various compressor types at different operating ranges and with various refrigerants. In addition, the modified test setup enables the investigation of long term liquid slug and its effects on the compressor. The modification comprises observational components, adjustments of the control system, safety measures and a customized oil recirculation system for compressors which do not contain an integrated oil sump or oil level regulation system. This paper describes the setup of the test bench, its functional principle, the key modifications, first test results and an evaluation of the energy balance.

  19. Kinetics of a gas adsorption compressor

    Science.gov (United States)

    Chan, C. K.; Tward, E.; Elleman, D. D.

    1984-01-01

    Chan (1981) has suggested that a process based on gas adsorption could be used as a means to drive a Joule-Thomson (J-T) device. The resulting system has several advantages. It is heat powered, it has no sealing, there are no mechanical moving parts, and no active control is required. In the present investigation, a two-phase model is used to analyze the transients of a gas adsorption compressor. The modeling of the adsorption process is based on a consideration of complete thermal and mechanical equilibrium between the gaseous phase and the adsorbed gas phase. The experimental arrangement for two sets of kinetic tests is discussed, and data regarding the experimental results are presented in graphs. For a theoretical study, a two-phase model was developed to predict the transient behavior of the compressor. A computer code was written to solve the governing equations with the aid of a standard forward marching predictor-corrector method.

  20. Rotating flux compressor for energy conversion

    International Nuclear Information System (INIS)

    Chowdhuri, P.; Linton, T.W.; Phillips, J.A.

    1983-01-01

    The rotating flux compressor (RFC) converts rotational kinetic energy into an electrical output pulse which would have higher energy than the electrical energy initially stored in the compressor. An RFC has been designed in which wedge-shaped rotor blades pass through the air gaps between successive turns of a solenoid, the stator. Magnetic flux is generated by pulsing the stator solenoids when the inductance is a maximum, i.e., when the flux fills the stator-solenoid volume. Connecting the solenoid across a load conserves the flux which is compressed within the small volume surrounding the stator periphery when the rotor blades cut into the free space between the stator plates, creating a minimum-inductance condition. The unique features of this design are: (1) no electrical connections (brushes) to the rotor; (2) no conventional windings; and (3) no maintenance. The device has been tested up to 5000 rpm of rotor speed

  1. High stability design for new centrifugal compressor

    Science.gov (United States)

    Kanki, H.; Katayama, K.; Morii, S.; Mouri, Y.; Umemura, S.; Ozawa, U.; Oda, T.

    1989-01-01

    It is essential that high-performance centrifugal compressors be free of subsynchronous vibrations. A new high-performance centrifugal compressor has been developed by applying the latest rotordynamics knowledge and design techniques: (1) To improve the system damping, a specially designed oil film seal was developed. This seal attained a damping ratio three times that of the conventional design. The oil film seal contains a special damper ring in the seal cartridge. (2) To reduce the destabilizing effect of the labyrinth seal, a special swirl canceler (anti-swirl nozzle) was applied to the balance piston seal. (3) To confirm the system damping margin, the dynamic simulation rotor model test and the full load test applied the vibration exciting test in actual load conditions.

  2. Centrifugal Compressors, Flow Phenomena and Performance.

    Science.gov (United States)

    1980-11-01

    r2 = 1.975 situated near diffuser exit/ collector entrance. Total temperature measure- ments have been performed at the compressor inlet and exit...non-square mesh is used in a two-dimensional flow calculation. In fact, this term is compounded of the product of a constant coefficient multiplying the...terms of the finite difference equations are evaluated from the zeroth approximation, i.e., the solution of Katsanis and McNally (1), while parabolic

  3. Advanced Compressor for Long Life Space Cryocoolers

    Science.gov (United States)

    1994-11-01

    625 and 718, or beryllium copper. When both high-yield and high- fatigue strength are required, Inconel 718 is usually the material of choice. As shown...with wear debris and life in the case of rubbing seals, and long-term stability and alignment in the case of precision noncontacting clearance seals, are...the bearings’ wear pv, and hence increased life, with decreasing stroke. In summary, the results of the compressor optimization studies showed that a

  4. Analysis of performance for centrifugal steam compressor

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Seung Hwan; Ryu, Chang Kook; Ko, Han Seo [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-12-15

    In this study, mean streamline and Computational fluid dynamics (CFD) analyses were performed to investigate the performance of a small centrifugal steam compressor using a latent heat recovery technology. The results from both analysis methods showed good agreement. The compression ratio and efficiency of steam were found to be related with those of air by comparing the compression performances of both gases. Thus, the compression performance of steam could be predicted by the compression performance of air using the developed dimensionless parameters.

  5. Analysis of performance for centrifugal steam compressor

    International Nuclear Information System (INIS)

    Kang, Seung Hwan; Ryu, Chang Kook; Ko, Han Seo

    2016-01-01

    In this study, mean streamline and Computational fluid dynamics (CFD) analyses were performed to investigate the performance of a small centrifugal steam compressor using a latent heat recovery technology. The results from both analysis methods showed good agreement. The compression ratio and efficiency of steam were found to be related with those of air by comparing the compression performances of both gases. Thus, the compression performance of steam could be predicted by the compression performance of air using the developed dimensionless parameters

  6. Axial forces in centrifugal compressor couplings

    Science.gov (United States)

    Ivanov, A. N.; Ivanov, N. M.; Yun, V. K.

    2017-08-01

    The article presents the results of the theoretical and experimental investigation of axial forces arising in the toothed and plate couplings of centrifugal compressor shaft lines. Additional loads on the thrust bearing are considered that can develop in the toothed couplings as a result of coupled rotors misalignment. Design relationships to evaluate the level of axial forces and recommendations for their reduction in the operating conditions are given.

  7. New concept single screw compressors and their manufacture technology

    Science.gov (United States)

    Feng, Q.; Liu, F.; Chang, L.; Feng, C.; Peng, C.; Xie, J.; van den Broek, M.

    2017-08-01

    Single screw compressors were generally acknowledged as one of the nearly perfect machines by compressor researchers and manufacturers. However the rapid wear of the star-wheel in a single screw compressor during operation is a key reason why it hasn’t previously joined the main current compressors’ market. After more than ten years of effective work, the authors of this paper have proposed a new concept single screw compressor whose mesh-couple profile is enveloped with multi-column. Also a new design method and manufacture equipment for this kind of compressor have been developed and are described in this paper. A lot of prototype tests and a long period of industrial operations under full loading conditions have shown that the mesh-couple profiles of the new concept single compressors have excellent anti-wearness.

  8. Separation of compressor oil from helium

    International Nuclear Information System (INIS)

    Strauss, R.; Perrotta, K.A.

    1982-01-01

    Compression of helium by an oil-sealed rorary screw compressor entrains as much as 4000 parts per million by weight of liquid and vapor oil impurities in the gas. The reduction below about 0.1 ppm for cryogenic applications is discussed. Oil seperation equipment designed for compressed air must be modified significantly to produce the desired results with helium. The main differences between air and helium filtration are described. A description of the coalescers is given with the continuous coalescing of liquid mist from air or other gas illustrated. Oil vapor in helium is discussed in terms of typical compressor oils, experimental procedure for measuring oil vapor concentration, measured volatile hydrocarbons in the lubricants, and calculated concentration of oil vapor in Helium. Liquid oil contamination in helium gas can be reduced well below 0.1 ppm by a properly designed multiple state coalescing filter system containing graded efficiency filter elements. The oil vapor problem is best attached by efficiently treating the oil to remove most of the colatiles before charging the compressor

  9. The analysis on centrifugal compressor rotating stall

    International Nuclear Information System (INIS)

    Kim, Ji Hwan; Kim, Kwang Ho; Shin, You Hwan

    2003-01-01

    In the present study, the performance characteristics and the number of stall cell during rotating stall of a centrifugal air compressor were experimentally investigated. Rotating stall in the vaneless diffuser were investigated by measuring unsteady pressure fluctuations at several different diffuser radius using a high frequency pressure transducer. The number of stall cell and their rotational speeds are distinctive features of the rotating stall phenomenon. The present study is mainly forced on the analysis for the stall cell number and its propagation speed unstable operating region of the compressor. The interpretation method of visualization is based on the pressure distribution in the circumference pressure fields while plotting the pressure and its harmonics variations in time in polar coordinates. To obtain the visualize the existence rotating stall, auto-correlation function and the frequency spectra of the pressure fluctuations were measured at r/r2=1.52. When the flow coefficient is lower than 0.150, the static pressure at impeller inlet is higher than that at inlet duct of the compressor. And the flow coefficient is lower than 0.086, several stall cell groups of discrete frequencies are observed

  10. Rotor-generated unsteady aerodynamic interactions in a 1½ stage compressor

    Science.gov (United States)

    Papalia, John J.

    Because High Cycle Fatigue (HCF) remains the predominant surprise failure mode in gas turbine engines, HCF avoidance design systems are utilized to identify possible failures early in the engine development process. A key requirement of these analyses is accurate determination of the aerodynamic forcing function and corresponding airfoil unsteady response. The current study expands the limited experimental database of blade row interactions necessary for calibration of predictive HCF analyses, with transonic axial-flow compressors of particular interest due to the presence of rotor leading edge shocks. The majority of HCF failures in aircraft engines occur at off-design operating conditions. Therefore, experiments focused on rotor-IGV interactions at off-design are conducted in the Purdue Transonic Research Compressor. The rotor-generated IGV unsteady aerodynamics are quantified when the IGV reset angle causes the vane trailing edge to be nearly aligned with the rotor leading edge shocks. A significant vane response to the impulsive static pressure perturbation associated with a shock is evident in the point measurements at 90% span, with details of this complex interaction revealed in the corresponding time-variant vane-to-vane flow field data. Industry wide implementation of Controlled Diffusion Airfoils (CDA) in modern compressors motivated an investigation of upstream propagating CDA rotor-generated forcing functions. Whole field velocity measurements in the reconfigured Purdue Transonic Research Compressor along the design speedline reveal steady loading had a considerable effect on the rotor shock structure. A detached rotor leading edge shock exists at low loading, with an attached leading edge and mid-chord suction surface normal shock present at nominal loading. These CDA forcing functions are 3--4 times smaller than those generated by the baseline NACA 65 rotor at their respective operating points. However, the IGV unsteady aerodynamic response to the CDA

  11. Modern high pressure gas injection centrifugal compressor for enhanced oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Almasi, Amin [Worley Parsons Services Pty Ltd, Brisbane, NSW (Australia). Mechanical Dept.

    2011-12-15

    This article covers different design, manufacturing, performance and reliability aspects of modern high pressure gas re-injection centrifugal compressor units. Advances and recent technologies on critical areas such as rotor dynamics, anti-surge system, rotating stall prevention, auxiliary systems, material selection, shop performance tests and gas sealing are studied. Three different case studies for modern re-injection machines including 12 MW, 15 MW and 32 MW trains are presented. (orig.)

  12. Method and refrigerants for replacing existing refrigerants in centrifugal compressors

    International Nuclear Information System (INIS)

    Kopko, W.L.

    1991-01-01

    This patent describes a method for replacing an existing refrigerant in a centrifugal compressor. It comprises selecting a desired impeller Mach number for the centrifugal compressor; selecting a base refrigerant constituent; combining at least one additive refrigerant constituent with the base refrigerant constituent to form a replacement refrigerant having at least one physical or chemical property different from the existing refrigerant and substantially providing the desired impeller Mach number in the centrifugal compressor; and replacing the existing refrigerant with the replacement refrigerant

  13. Experimental Pressure-Volume diagrams of scroll compressors

    OpenAIRE

    Picavet, Alain; Ginies, Pierre

    2014-01-01

    This paper presents the results of tests led with scroll compressors to establish pressure-volume diagrams. Two compressors were thinly instrumented with pressure and displacement sensors so as to follow the whole compression process, from suction to exhaust. A gear coder was set to mark off the closing and opening of gas pockets, and to study the speed variations occurring during a single rotation. These tests help to understand the various phenomena met in a compressor, such as back-flow, o...

  14. An alternative compressor. A study; Alternativ kompressor. En udredning

    Energy Technology Data Exchange (ETDEWEB)

    Dall, O.; Jensen, F.; Danig, P.O.; Ritchie, E.; Kierkegaard, P.

    1997-10-01

    A linear compressor would be suitable for refrigerating systems with small effect. A computerized control system can be used to control the speed of a linear engine. A new compressor/engine with much improved energy efficiency can be designed to operate oil-free. The novel design of a compressor with smaller piston displacement is smaller than the existing models and thus more suitable for the future refrigerators. (EG) EFP-97. 71 refs.

  15. Variable speed gas engine-driven air compressor system

    Science.gov (United States)

    Morgan, J. R.; Ruggles, A. E.; Chen, T. N.; Gehret, J.

    1992-11-01

    Tecogen Inc. and Ingersoll-Rand Co. as a subcontractor have designed a nominal 150-hp gas engine-driven air compressor utilizing the TECODRIVE 8000 engine and the Ingersoll-Rand 178.5-mm twin screw compressor. Phase 1 included the system engineering and design, economic and applications studies, and a draft commercialization plan. Phase 2 included controls development, laboratory prototype construction, and performance testing. The testing conducted verified that the compressor meets all design specifications.

  16. Economics of water injected air screw compressor systems

    OpenAIRE

    Madhav, K. V.; Kovacevic, A.

    2015-01-01

    There is a growing need for compressed air free of entrained oil to be used in industry. In many cases it can be supplied by oil flooded screw compressors with multi stage filtration systems, or by oil free screw compressors. However, if water injected screw compressors can be made to operate reliably, they could be more efficient and therefore cheaper to operate. Unfortunately, to date, such machines have proved to be insufficiently reliable and not cost effective. This paper describes an in...

  17. Air-Cooled Design of a Temperature-Swing Adsorption Compressor for Closed-Loop Air Revitalization Systems

    Science.gov (United States)

    Mulloth, Lila M.; Affleck, Dave L.; Rosen, Micha; LeVan, M. Douglas; Wang, Yuan; Cavalcante, Celio L.

    2004-01-01

    The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. We have a developed a temperature-swing adsorption compressor (TSAC) for performing these tasks that is energy efficient, quiet, and has no rapidly moving parts. This paper discusses the mechanical design and the results of thermal model validation tests of a TSAC that uses air as the cooling medium.

  18. Aspirated Compressors for High Altitude Engines, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Aurora Flight Sciences proposes to incorporate aspirated compressor technology into a high altitude, long endurance (HALE) concept engine. Aspiration has been proven...

  19. Economics of water injected air screw compressor systems

    Science.gov (United States)

    Venu Madhav, K.; Kovačević, A.

    2015-08-01

    There is a growing need for compressed air free of entrained oil to be used in industry. In many cases it can be supplied by oil flooded screw compressors with multi stage filtration systems, or by oil free screw compressors. However, if water injected screw compressors can be made to operate reliably, they could be more efficient and therefore cheaper to operate. Unfortunately, to date, such machines have proved to be insufficiently reliable and not cost effective. This paper describes an investigation carried out to determine the current limitations of water injected screw compressor systems and how these could be overcome in the 15-315 kW power range and delivery pressures of 6-10 bar. Modern rotor profiles and approach to sealing and cooling allow reasonably inexpensive air end design. The prototype of the water injected screw compressor air system was built and tested for performance and reliability. The water injected compressor system was compared with the oil injected and oil free compressor systems of the equivalent size including the economic analysis based on the lifecycle costs. Based on the obtained results, it was concluded that water injected screw compressor systems could be designed to deliver clean air free of oil contamination with a better user value proposition than the oil injected or oil free screw compressor systems over the considered range of operations.

  20. Possibility of Thermomechanical Compressor Application in Desalination Plants

    Science.gov (United States)

    Blagin, E. V.; Shimanov, A. A.; Uglanov, D. A.; Korneev, S. S.

    2018-01-01

    This article deals with estimation of thermocompressor operating possibility in desalination plant with mechanical vapour compressor. In this plant thermocompressor is used instead of commonly used centrifugal compressor. Preliminary analysis shows that such plant is able to operate, however, power consumption is 3.5-6.5 higher in comparison with traditional MVC plant. In turn, utilization of thermocompressor allows avoiding usual high-frequency drive of centrifugal compressor. Drives with frequency of 50 Hz are enough for thermocompressor when centrifugal compressor requires drives with frequency up to 500 Hz and higher. Approximate thermocompressor dimensions are estimated.

  1. Rotating stall simulation for axial and centrifugal compressors

    Science.gov (United States)

    Halawa, Taher; Gadala, Mohamed S.

    2017-05-01

    This study presents a numerical simulation of the rotating stall phenomenon in axial and centrifugal compressors with detailed descriptions of stall precursors and its development with time. Results showed that the vaneless region of the centrifugal compressor is the most critical location affected by stall. It was found that the tip leakage flow and the back flow impingement are the main cause of the stall development at the impeller exit area for centrifugal compressors. The results of the axial compressor simulations indicated that the early separated flow combined with the tip leakage flow can block the impeller passages during stall.

  2. Design of small centrifugal compressor test model for a supercritical CO2 compressor in the fast reactor power plant

    International Nuclear Information System (INIS)

    Muto, Y.; Ishizuka, T.; Aritomi, M.

    2008-01-01

    In order to clarify the CO 2 compressor performance in the vicinity of critical point, a research project has been started in Tokyo Institute of Technology based on Japanese government fund. This paper describes how fundamental parameters were selected and sizing of a small and high speed impeller of the test centrifugal compressor. The concept of canned type compressor structures provided with high speed electric motor and preliminary aerodynamic performance prediction are also given. (authors)

  3. Relevance of chest sonography in the diagnosis of acute respiratory failure: Comparison with current diagnostic tools in intensive care units

    Directory of Open Access Journals (Sweden)

    Rasha Daabis

    2014-10-01

    Conclusions: Lung ultrasound provided an immediate diagnosis of the underlying etiology of acute respiratory failure in most cases; it can therefore be added to the armamentarium of ICU where urgent decisions are needed for rapid diagnosis and management of patients with ARF.

  4. Energy and exergy recovery in a natural gas compressor station – A technical and economic analysis

    International Nuclear Information System (INIS)

    Kostowski, Wojciech J.; Kalina, Jacek; Bargiel, Paweł; Szufleński, Paweł

    2015-01-01

    Highlights: • Energy and exergy flow in a natural gas compressor station. • Operational efficiency only 18.3% vs. 35.1% nominal. • 3 energy/exergy recovery systems proposed. • Up to 168.9 GW h/y electricity and 6.5 GW h/y heat recoverable. • Legal obstacles: operators not allowed to produce electricity. - Abstract: The paper presents possible solutions to improve the thermodynamic performance of a natural gas compressor station equipped with various type of compressor units and operated at part-load conditions. A method for setting a simplified energy and exergy balance based on the available metering information has been presented. For a case study plant, it has been demonstrated that the current part-load operation leads to a significant decrease in energy and exergy efficiency compared to the nominal state of machinery. Three alternative improvement strategies have been proposed: (1) installation of a heat recovery hot water generator for covering the existing heat demand of the plant; (2) installation of a heat recovery thermal oil heater for covering the existing heat demand and driving an organic Rankine cycle (ORC) for electricity generation; (3) installation of a heat recovery thermal oil heater with and ORC and gas expanders for switching into full-load operation of the gas turbine unit. Energy and exergy performance of the proposed strategies as well as their economic feasibility have been analyzed. The second scenario involving an ORC unit provides the highest local energy savings, however, its economic feasibility is not achieved under the current part-load operating conditions. A hypothetic scenario of the same station operated at full-load due to an increased gas transmission capacity demonstrate the economic feasibility (possible under optimistic price conditions). Finally, it has been shown that the possibility of waste energy recovery from natural gas transmission systems (in particular, from compressor stations) depends on legal

  5. STATISTICAL ANALYSIS OF DAMAGEABILITY OF THE BYPASS ENGINES COMPRESSOR BLADES

    Directory of Open Access Journals (Sweden)

    Boris A. Chichkov

    2018-01-01

    Full Text Available Aircraft gas turbine engines during the operation are exposed to damage of flowing parts. The elements of the engine design, appreciably determining operational characteristics are rotor blades. Character of typical damages for various types of engines depends on appointment and a geographical place of the aircraft operation on which one or another engine is installed. For example, the greatest problem for turboshaft engines operated in the dusty air conditions is erosive wear of a rotor blade airfoil. Among principal causes of flowing parts damages of bypass engine compressors are foreign object damages. Independently there are the damages caused by fatigue of a rotor blade material at dangerous blade mode. Pieces of the ice formed in the input unit, birds and the like can also be a source of danger. The foreign objects getting into the engine from runway are nuts, bolts, pieces of tire protectors, lock-wire, elements from earlier flying off aircraft, etc. The entry of foreign objects into the engine depends on both an operation mode (during the operation on the ground, on takeoff, on landing roll using the reverse and so on, and the aircraft engine position.Thus the foreign objects entered into the flowing path of bypass engine damage blade cascade of low and high pressure. Foreign objects entered into the flowing part of the engine with rotor blades result in dents on edges and blade shroud, deformations of edges, breakage, camber of peripheral parts and are distributed "nonlinear" on path length (steps. The article presents the results of the statistical analysis of three types engine compressors damageability over the period of more than three years. Damages are divided according to types of engines in whole and to their separate steps, depths and lengths, blades damage location. The results of the analysis make it possible to develop recommendations to carry out the optical-visual control procedures.

  6. WE-H-BRC-01: Failure Mode and Effects Analysis of Skin Electronic Brachytherapy Using Esteya Unit

    International Nuclear Information System (INIS)

    Ibanez-Rosello, B; Bautista-Ballesteros, J; Bonaque, J; Lliso, F; Carmona, V; Gimeno, J; Ouhib, Z; Perez-Calatayud, J

    2016-01-01

    Purpose: A failure mode and effect analysis (FMEA) of skin lesions treatment process using Esteya™ device (Elekta Brachyterapy, Veenendaal, The Netherlands) was performed, with the aim of increasing the quality of the treatment and reducing the likelihood of unwanted events. Methods: A multidisciplinary team with experience in the treatment process met to establish the process map, which outlines the flow of various stages for such patients undergoing skin treatment. Potential failure modes (FM) were identified and the value of severity (S), frequency of occurrence (O), and lack of detectability (D) of the proposed FM were scored individually, each on a scale of 1 to 10 following TG-100 guidelines of the AAPM. These failure modes were ranked according to our risk priority number (RPN) and S scores. The efficiency of existing quality management tools was analyzed through a reassessment of the O and D made by consensus. Results: 149 FM were identified, 43 of which had RPN ≥ 100 and 30 had S ≥ 7. After introduction of the tools of quality management, only 3 FM had RPN ≥ 100 and 22 FM had RPN ≥ 50. These 22 FM were thoroughly analyzed and new tools for quality management were proposed. The most common cause of highest RPN FM was associated with the heavy patient workload and the continuous and accurate applicator-patient skin contact during the treatment. To overcome this second item, a regular quality control and setup review by a second individual before each treatment session was proposed. Conclusion: FMEA revealed some of the FM potentials that were not predicted during the initial implementation of the quality management tools. This exercise was useful in identifying the need of periodic update of the FMEA process as new potential failures can be identified.

  7. WE-H-BRC-01: Failure Mode and Effects Analysis of Skin Electronic Brachytherapy Using Esteya Unit

    Energy Technology Data Exchange (ETDEWEB)

    Ibanez-Rosello, B; Bautista-Ballesteros, J; Bonaque, J; Lliso, F; Carmona, V; Gimeno, J [Hospital La Fe, Valencia, Valencia (Spain); Ouhib, Z [Lynn Regional Cancer Center, Delray Beach, FL (United States); Perez-Calatayud, J [Hospital La Fe, Valencia, Valencia (Spain); Clinica Benidorm, Benidorm, Alicante (Spain)

    2016-06-15

    Purpose: A failure mode and effect analysis (FMEA) of skin lesions treatment process using Esteya™ device (Elekta Brachyterapy, Veenendaal, The Netherlands) was performed, with the aim of increasing the quality of the treatment and reducing the likelihood of unwanted events. Methods: A multidisciplinary team with experience in the treatment process met to establish the process map, which outlines the flow of various stages for such patients undergoing skin treatment. Potential failure modes (FM) were identified and the value of severity (S), frequency of occurrence (O), and lack of detectability (D) of the proposed FM were scored individually, each on a scale of 1 to 10 following TG-100 guidelines of the AAPM. These failure modes were ranked according to our risk priority number (RPN) and S scores. The efficiency of existing quality management tools was analyzed through a reassessment of the O and D made by consensus. Results: 149 FM were identified, 43 of which had RPN ≥ 100 and 30 had S ≥ 7. After introduction of the tools of quality management, only 3 FM had RPN ≥ 100 and 22 FM had RPN ≥ 50. These 22 FM were thoroughly analyzed and new tools for quality management were proposed. The most common cause of highest RPN FM was associated with the heavy patient workload and the continuous and accurate applicator-patient skin contact during the treatment. To overcome this second item, a regular quality control and setup review by a second individual before each treatment session was proposed. Conclusion: FMEA revealed some of the FM potentials that were not predicted during the initial implementation of the quality management tools. This exercise was useful in identifying the need of periodic update of the FMEA process as new potential failures can be identified.

  8. Dual-worm screw compressors; Compresseurs bi-vis

    Energy Technology Data Exchange (ETDEWEB)

    Baleydier, J P [Bitzer France, 69 - Lyon (France)

    1998-12-31

    Low power worm-screw moto-compressors are used in any king of refrigerating machineries and more and more in air conditioning systems. This paper presents the principle of dual-screw moto-compressors: worm-screw technology, role of oil (lubrication, tightness, cooling), compression, internal pressure, power reduction, lubrication, economizer, operation, model selection and accessories. (J.S.)

  9. Sound reduction of air compressors using a systematic approach

    Science.gov (United States)

    Moylan, Justin Tharp

    The noise emitted by portable electric air compressors can often be a nuisance or potentially hazardous to the operator or others nearby. Therefore, reducing the noise of these air compressors is desired. This research focuses on compressors with a reciprocating piston design as this is the most common type of pump design for portable compressors. An experimental setup was developed to measure the sound and vibration of the air compressors, including testing inside a semi-anechoic chamber. The design of a quiet air compressor was performed in four stages: 1) Teardown and benchmarking of air compressors, 2) Identification and isolation of noise sources, 3) Development of individual means to quiet noise sources, 4) Selection and testing of integrated solutions. The systematic approach and results for each of these stages will be discussed. Two redesigned solutions were developed and measured to be approximately 65% quieter than the previous unmodified compressor. An additional analysis was performed on the solutions selected by the participants involved in the selection process. This analysis involved determining which of the design criteria each participant considered most important when selecting solutions. The results from each participant were then compared to their educational background and experience and correlations were identified. The correlations discovered suggest that educational background and experience may be key determinants for the preference models developed.

  10. 78 FR 1162 - Cardiovascular Devices; Reclassification of External Cardiac Compressor

    Science.gov (United States)

    2013-01-08

    .... FDA-2012-N-1173] Cardiovascular Devices; Reclassification of External Cardiac Compressor AGENCY: Food... external cardiac compressors as class III requiring premarket approval. The Cardiovascular Device... on CPR and emergency cardiovascular care (Ref. 1) conclude that ``real-time CPR prompting and...

  11. 46 CFR 154.534 - Cargo pumps and cargo compressors.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo pumps and cargo compressors. 154.534 Section 154.534 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES... Equipment Cargo and Process Piping Systems § 154.534 Cargo pumps and cargo compressors. Cargo pumps and...

  12. Dual-worm screw compressors; Compresseurs bi-vis

    Energy Technology Data Exchange (ETDEWEB)

    Baleydier, J.P. [Bitzer France, 69 - Lyon (France)

    1997-12-31

    Low power worm-screw moto-compressors are used in any king of refrigerating machineries and more and more in air conditioning systems. This paper presents the principle of dual-screw moto-compressors: worm-screw technology, role of oil (lubrication, tightness, cooling), compression, internal pressure, power reduction, lubrication, economizer, operation, model selection and accessories. (J.S.)

  13. Experiments with Liquid Propellant Jet Ignition in a Ballistic Compressor

    National Research Council Canada - National Science Library

    Birk, Avi

    1998-01-01

    .... The apparatus consists of an inline ballistic compressor and LP injector. The rebound of the ballistic compressor piston was arrested, trapping 40 to 55 MPa of 750 to 8500 C argon for ignition of circular jets in a windowed test chamber...

  14. Analysis of ideal sorption compressor cycles operating with gas mixtures

    NARCIS (Netherlands)

    Tzabar, N.; ter Brake, H.J.M.

    2018-01-01

    Sorption-based compressors are thermally driven and because of the absence of moving parts they are vibration free, and have the potential for long life. Sorption-based compressors have been reported to operate Joule–Thomson (JT) cryogenic coolers with pure working fluids. However, using mixed

  15. High Efficiency Pneumatic Systems Compressors Hydrodynamics and Termodynamics Process Research

    Directory of Open Access Journals (Sweden)

    Paulius Bogdevičius

    2016-12-01

    Full Text Available The paper analyzes pneumatic system, which consists of three piston compressors, pipes and reciever. Designed two cylinder piston compressor with an asynchronous electric motor mathematical model. In the mathematical model has been estimated rod mechanism geometry and kinematic parameters also hudrodynamics and thermodynamic processes going in the cylinders. Also there were made mathematical experiment and presented the results of it.

  16. Transient analysis of a variable speed rotary compressor

    International Nuclear Information System (INIS)

    Park, Youn Cheol

    2010-01-01

    A transient simulation model of a rolling piston type rotary compressor is developed to predict the dynamic characteristics of a variable speed compressor. The model is based on the principles of conservation, real gas equations, kinematics of the crankshaft and roller, mass flow loss due to leakage, and heat transfer. For the computer simulation of the compressor, the experimental data were obtained from motor performance tests at various operating frequencies. Using the developed model, re-expansion loss, friction loss, mass flow loss and heat transfer loss is estimated as a function of the crankshaft speed in a variable speed compressor. In addition, the compressor efficiency and energy losses are predicted at various compressor-operating frequencies. Since the transient state of the compressor strongly depends on the system, the developed model is combined with a transient system simulation program to get transient variations of the compression process in the system. Motor efficiency, mechanical efficiency, motor torque and volumetric efficiency are calculated with respect to variation of the driving frequency in a rotary compressor.

  17. Air Compressor Driving with Synchronous Motors at Optimal Parameters

    Directory of Open Access Journals (Sweden)

    Iuliu Petrica

    2010-10-01

    Full Text Available In this paper a method of optimal compensation of the reactive load by the synchronous motors, driving the air compressors, used in mining enterprises is presented, taking into account that in this case, the great majority of the equipment (compressors, pumps are generally working a constant load.

  18. Axial and Centrifugal Compressor Mean Line Flow Analysis Method

    Science.gov (United States)

    Veres, Joseph P.

    2009-01-01

    This paper describes a method to estimate key aerodynamic parameters of single and multistage axial and centrifugal compressors. This mean-line compressor code COMDES provides the capability of sizing single and multistage compressors quickly during the conceptual design process. Based on the compressible fluid flow equations and the Euler equation, the code can estimate rotor inlet and exit blade angles when run in the design mode. The design point rotor efficiency and stator losses are inputs to the code, and are modeled at off design. When run in the off-design analysis mode, it can be used to generate performance maps based on simple models for losses due to rotor incidence and inlet guide vane reset angle. The code can provide an improved understanding of basic aerodynamic parameters such as diffusion factor, loading levels and incidence, when matching multistage compressor blade rows at design and at part-speed operation. Rotor loading levels and relative velocity ratio are correlated to the onset of compressor surge. NASA Stage 37 and the three-stage NASA 74-A axial compressors were analyzed and the results compared to test data. The code has been used to generate the performance map for the NASA 76-B three-stage axial compressor featuring variable geometry. The compressor stages were aerodynamically matched at off-design speeds by adjusting the variable inlet guide vane and variable stator geometry angles to control the rotor diffusion factor and incidence angles.

  19. Management of kyphoscoliosis patients with respiratory failure in the intensive care unit and during long term follow up

    Directory of Open Access Journals (Sweden)

    Adıgüzel Nalan

    2012-09-01

    Full Text Available Abstract Background We aimed to evaluate the ICU management and long-term outcomes of kyphoscoliosis patients with respiratory failure. Methods A retrospective observational cohort study was performed in a respiratory ICU and outpatient clinic from 2002–2011. We enrolled all kyphoscoliosis patients admitted to the ICU and followed-up at regular intervals after discharge. Reasons for acute respiratory failure (ARF, ICU data, mortality, length of ICU stay and outpatient clinic data, non-invasive ventilation (NIV device settings, and compliance were recorded. NIV failure in the ICU and the long term effect of NIV on pulmonary performance were analyzed. Results Sixty-two consecutive ICU kyphoscoliosis patients with ARF were enrolled in the study. NIV was initially applied to 55 patients, 11 (20% patients were intubated, and the majority had sepsis and septic shock (p  Conclusions We strongly discourage the use of NIV in the case of septic shock in ICU kyphoscoliosis patients with ARF. Pulmonary performance improved with NIV during long term follow up.

  20. Piston-Skirt Lubrication System For Compressor

    Science.gov (United States)

    Schroeder, Edgar C.; Burzynski, Marion, Jr.

    1994-01-01

    Piston-skirt lubrication system provides steady supply of oil to piston rings of gas compressor. No need for oil-filled crankcase or external oil pump. Instead, part of each piston acts as its own oil pump circulating oil from reservoir. Annular space at bottom of piston and cylinder constitutes working volume of small oil pump. Depending on application, reservoir open to atmosphere, or sealed and pressurized in bellows to prevent contact between oil and atmosphere. Filter removes particles worn away from piston rings and cylinder wall during normal operation.

  1. DESIGN PARAMETERS OF CENTRIFUGAL COMPRESSOR INDUCER

    Directory of Open Access Journals (Sweden)

    Saim KOÇAK

    1998-03-01

    Full Text Available Design characteristics of centrifugal compressor impellers working with compressible fluids are analyzed, and the design parameters of inducer are defined. The effects of incidence, deviation and deflection angles, relative eddy, rotating stall and Mach number are investigated. The relation between minimum relative Mach number of inducer and flow angle is investigated and it is observed that the minimum Mach number occurs for flow angle values between -680 and -520 . In the design, the effect of a 100 difference in flow angle is found to be less than 1 % on minimum relative Mach number.

  2. Retrofitting compressor engines to reduce emissions

    International Nuclear Information System (INIS)

    Collison, Melanie

    2011-01-01

    Cenovus Energy Inc. is upgrading its natural gas compression facilities at 37 sites it operates in Alberta. The project itself consists of a retrofit of the natural-fas fired engines that power the compressors that fill its natural gas sales pipe-line. Piping to capture fugitive natural gas will also be installed. These emissions will be used as fuel. The efficiency rating of such engine will be the same as a new fuel-injected engine. One of the challenge in the design of the parts of these engines ss to to ensure the least possible downtime to minimize production losses.

  3. Thermal modelling of a dry revolving vane compressor

    Science.gov (United States)

    Ooi, K. T.; Aw, K. T.

    2017-08-01

    The lubricant used in compressors serves to lubricate, to seal the gaps to reduce internal leakage and to a certain extent, to cool. However, a lubricant free compressor is attractive if lubricants become a source of contaminant, or in areas where the compressor needs be placed under any orientation, such as those in military or portable computing. In this paper, a thermal model for a dry revolving vane compressor is presented. This thermal model sets out to predict the steady-state operating temperatures of the compressor components. The lumped thermal conductance method was employed. The results of the components temperature will be presented and discussed. A high potential for overheating is observed at the shaft bearings.

  4. Safe and efficient operation of multistage cold compressor systems

    International Nuclear Information System (INIS)

    Kauschke, M.; Haberstroh, C.; Quack, H.

    1996-01-01

    Large refrigeration rates in the temperature range of super fluid helium can only be obtained with the help of centrifugal cold compressors. For the large 2 K systems, four compression stages are necessary to reach atmospheric pressure. Centrifugal cold compressors are quite sensitive to mass flow and suction temperature variations; but these have to be expected in a real system. The first step in the systems design is to find safe and efficient quasi-stationary modes of operation. The system which is being proposed for the TESLA refrigerators relies on two features. The first is to allow the room temperature screw compressor, downstream of the cold compressors to work occasionally with a subatmospheric suction pressure. The second is to stabilize the suction temperature of the third stage of compression at about 10 K. With these features it is possible, that in all modes of operation all four compressor stages operate exactly at their design point

  5. Combined cold compressor/ejector helium refrigerator cycle

    International Nuclear Information System (INIS)

    Schlafke, A.P.; Brown, D.P.; Wu, K.C.

    1984-01-01

    This chapter demonstrates how the use of a cold compressor in series with an ejector is an effective way to produce the desired low pressure in a helium refrigeration system. The cold compressor is tentatively located at the low pressure side below the J-T heat exchanger. The ejector is the first stage and the cold compressor is the second stage of the two-stage pumping system. A centrifugal, oil-bearing type compressor was installed on the R and D refrigerator at the Brookhaven National Laboratory. It is determined that the combined cold compressor and ejector system produces a lower temperature on the same load or more cooling at the same temperature compared with a system which uses an ejector alone. Results of the test showed a gain of 20%

  6. IC ENGINE SUPERCHARGING AND EXHAUST GAS RECIRCULATION USING JET COMPRESSOR

    Directory of Open Access Journals (Sweden)

    Adhimoulame Kalaisselvane

    2010-01-01

    Full Text Available Supercharging is a process which is used to improve the performance of an engine by increasing the specific power output whereas exhaust gas recirculation reduces the NOx produced by engine because of supercharging. In a conventional engine, supercharger functions as a compressor for the forced induction of the charge taking mechanical power from the engine crankshaft. In this study, supercharging is achieved using a jet compressor. In the jet compressor, the exhaust gas is used as the motive stream and the atmospheric air as the propelled stream. When high pressure motive stream from the engine exhaust is expanded in the nozzle, a low pressure is created at the nozzle exit. Due to this low pressure, atmospheric air is sucked into the expansion chamber of the compressor, where it is mixed and pressurized with the motive stream. The pressure of the mixed stream is further increased in the diverging section of the jet compressor. A percentage volume of the pressurized air mixture is then inducted back into the engine as supercharged air and the balance is let out as exhaust. This process not only saves the mechanical power required for supercharging but also dilutes the constituents of the engine exhaust gas thereby reducing the emission and the noise level generated from the engine exhaust. The geometrical design parameters of the jet compressor were obtained by solving the governing equations using the method of constant rate of momentum change. Using the theoretical design parameters of the jet compressor, a computational fluid dinamics analysis using FLUENT software was made to evaluate the performance of the jet compressor for the application of supercharging an IC engine. This evaluation turned out to be an efficient diagnostic tool for determining performance optimization and design of the jet compressor. A jet compressor was also fabricated for the application of supercharging and its performance was studied.

  7. Novel Long Stroke Reciprocating Compressor for Energy Efficient Jaggery Making

    Science.gov (United States)

    Rane, M. V.; Uphade, D. B.

    2017-08-01

    Novel Long Stroke Reciprocating Compressor is analysed for jaggery making while avoiding burning of bagasse for concentrating juice. Heat of evaporated water vapour along with small compressor work is recycled to enable boiling of juice. Condensate formed during heating of juice is pure water, as oil-less compressor is used. Superheat of compressor is suppressed by flow of superheated vapours through condensate. It limits heating surface temperature and avoids caramelization of sugar. Thereby improves quality of jaggery and eliminates need to use chemicals for colour improvement. Stroke to bore ratio is 0.6 to 1.2 in conventional reciprocating drives. Long stroke in reciprocating compressors enhances heat dissipation to surrounding by providing large surface area and increases isentropic efficiency by reducing compressor outlet temperature. Longer stroke increases inlet and exit valve operation timings, which reduces inertial effects substantially. Thereby allowing use of sturdier valves. This enables handling liquid along with vapour in compressors. Thereby supressing the superheat and reducing compressor power input. Longer stroke increases stroke to clearance ratios which increases volumetric efficiency and ability of compressor to compress through higher pressure ratios efficiently. Stress-strain simulation is performed in SolidWorks for gear drive. Long Stroke Reciprocating Compressor is developed at Heat Pump Laboratory, stroke/bore 292 mm/32 mm. It is operated and tested successfully at different speeds for operational stability of components. Theoretical volumetric efficiency is 93.9% at pressure ratio 2.0. Specific energy consumption is 108.3 kWhe/m3 separated water, considering free run power.

  8. Potential of flow pre-whirl at the compressor inlet of automotive engine turbochargers to enlarge surge margin and overcome packaging limitations

    International Nuclear Information System (INIS)

    Galindo, J.; Serrano, J.R.; Margot, X.; Tiseira, A.; Schorn, N.; Kindl, H.

    2007-01-01

    Due to the packaging constraints to which turbocharged engines are submitted in passenger cars, the inlet duct of the centrifugal compressor often requires a 90 o bend. The compressor inlet perpendicular to its axis disturbs the flow and reduces the compressor performance. This paper presents an interesting solution based on a specifically designed inlet swirl-generator device (SGD) that palliates these negative effects. In addition, the SGD can be used to extend the surge margin of the compressor if the position of the SGD blades is modified in function of the reciprocating engine operation conditions. The paper describes how the swirl level and the pressure losses generated by the device have been characterized in a continuous flow test rig. After this the SGD plus a centrifugal compressor from a turbocharger unit have been tested in a specific turbocharger test bench. The results obtained show the influence of the SGD blades position on the compressor performance. In order to better understand the influence of the SGD on the turbocharger behaviour, the flow velocity triangles near the inducer have been reconstructed using an approach based on CFD calculations

  9. Safety Management of a Clinical Process Using Failure Mode and Effect Analysis: Continuous Renal Replacement Therapies in Intensive Care Unit Patients.

    Science.gov (United States)

    Sanchez-Izquierdo-Riera, Jose Angel; Molano-Alvarez, Esteban; Saez-de la Fuente, Ignacio; Maynar-Moliner, Javier; Marín-Mateos, Helena; Chacón-Alves, Silvia

    2016-01-01

    The failure mode and effect analysis (FMEA) may improve the safety of the continuous renal replacement therapies (CRRT) in the intensive care unit. We use this tool in three phases: 1) Retrospective observational study. 2) A process FMEA, with implementation of the improvement measures identified. 3) Cohort study after FMEA. We included 54 patients in the pre-FMEA group and 72 patients in the post-FMEA group. Comparing the risks frequencies per patient in both groups, we got less cases of under 24 hours of filter survival time in the post-FMEA group (31 patients 57.4% vs. 21 patients 29.6%; p FMEA, there were several improvements in the management of intensive care unit patients receiving CRRT, and we consider it a useful tool for improving the safety of critically ill patients.

  10. Failure study of helium-cooled tungsten divertor plasma-facing units tested at DEMO relevant steady-state heat loads

    International Nuclear Information System (INIS)

    Ritz, G; Pintsuk, G; Linke, J; Hirai, T; Norajitra, P; Reiser, J; Giniyatulin, R; Makhankov, A; Mazul, I

    2009-01-01

    Tungsten was selected as armor material for the helium-cooled divertor in future DEMO-type fusion reactors and fusion power plants. After realizing the design and testing of them under cyclic thermal loads of up to ∼14 MW m -2 , the tungsten divertor plasma-facing units were examined by metallography; they revealed failures such as cracks at the thermal loaded and as-machined surfaces, as well as degradation of the brazing layers. Furthermore, in order to optimize the machining processes, the quality of tungsten surfaces prepared by turning, milling and using a diamond cutting wheel were examined. This paper presents a metallographic examination of the tungsten plasma-facing units as well as technical studies and the characterization on machining of tungsten and alternative brazing joints.

  11. Failure study of helium-cooled tungsten divertor plasma-facing units tested at DEMO relevant steady-state heat loads

    Science.gov (United States)

    Ritz, G.; Hirai, T.; Norajitra, P.; Reiser, J.; Giniyatulin, R.; Makhankov, A.; Mazul, I.; Pintsuk, G.; Linke, J.

    2009-12-01

    Tungsten was selected as armor material for the helium-cooled divertor in future DEMO-type fusion reactors and fusion power plants. After realizing the design and testing of them under cyclic thermal loads of up to ~14 MW m-2, the tungsten divertor plasma-facing units were examined by metallography; they revealed failures such as cracks at the thermal loaded and as-machined surfaces, as well as degradation of the brazing layers. Furthermore, in order to optimize the machining processes, the quality of tungsten surfaces prepared by turning, milling and using a diamond cutting wheel were examined. This paper presents a metallographic examination of the tungsten plasma-facing units as well as technical studies and the characterization on machining of tungsten and alternative brazing joints.

  12. Evaluation of the Implementation of an educational intervention nurse in patients treated at the Heart Failure Unit at the University Hospital Puerta de Hierro

    Directory of Open Access Journals (Sweden)

    Aurora Hernández Rivas

    2012-11-01

    Full Text Available Objective: To evaluate the effectiveness of the implementation of a nurse educational intervention in patients with heart failure in relation to the level of knowledge about their disease, level of self-care, treatment adherence, perceived satisfaction, fewer hospital readmissions and improved quality of life. Methods: Quasi-experimental study with two groups: control group (consisting of patients treated according to standard practice and experimental group (consisting of patients who will apply the nursing educational intervention proposal. It included all patients (= 18 years, good cognitive, literacy, sign informed consent with a diagnosis of heart failure (HF of recent (3-6 months or new onset, coming first in the Heart Failure Unit of Hospital Universitario Puerta de Hierro from May 2008. Sample: 68 patients per group. Nurse educational intervention will consist of four teaching sessions of 20 minutes before discharge, will be given a boost educational DVD, complete with brochures and explanatory guide, it will reinforce the information a month by telephone. Monitoring: baseline visit (inclusion and follow-up after 15 days, at 3 and 6 months. Outcomes/Instruments: demographic and clinical/exploration and medical history; quality of life, knowledge, self-care and medication adherence/validated questionnaires. Analysis: measures of central tendency and dispersion. Analysis by treatment assignment.

  13. Unsteady flow measurements in centrifugal compressors

    International Nuclear Information System (INIS)

    Bammert, K.; Mobarak, A.; Rautenberg, M.

    1976-01-01

    Centrifugal compressors and blowers are often used for recycling the coolant gas in gas-cooled reactors. To achieve the required high pressure ratios, highly loaded centrifugal compressors are built. The paper deals with unsteady flow measurements on highly loaded centrifugal impellers. Measurements of the approaching flow have been done with hot wires. The method of measurement enabled us to get the velocity distribution across the pitch ahead of the inducer. The static pressure signals along the shroud line has been discussed on the basis of some theoretical considerations. Accordingly the form of flow in the impeller and the wave flow or separation zones in the impeller can now be better interpreted. The importance of the unsteady nature of the relative flow, especially at impeller exit, is clearly demonstrated. Measurements with high responsive total pressure probes in the vicinity of impeller exit and the subsequent calculations have shown, that the instantaneous energy transfer at a certain point after the impeller may differ by more than 30% from the Euler work. Lastly, unsteady pressure measurements along the shroud line have been performed during surge and rotating stall. The surge signal have been analyzed in more detail and the mechanism of flow rupture and pressure recovery during a surge cycle is thoroughly discussed. (orig.) [de

  14. Compressor Part II: Volute Flow Predictions

    Directory of Open Access Journals (Sweden)

    Yu-Tai Lee

    1999-01-01

    Full Text Available A numerical method that solves the Reynolds-averaged Navier-Stokes equations is used to study an inefficient component of a shipboard air-conditioning HCFC-124 compressor system. This high-loss component of the centrifugal compressor was identified as the volute through a series of measurements given in Part I of the paper. The predictions were made using three grid topologies. The first grid closes the connection between the cutwater and the discharge diffuser. The other two grids connect the cutwater area with the discharge diffuser. Experiments were performed to simulate both the cutwater conditions used in the predictions. Surface pressures along the outer wall and near the inlet of the volute were surveyed for comparisons with the predictions. Good agreements between the predicted results and the measurements validate the calculations. Total pressure distributions and flow stream traces from the prediction results support the loss distribution through the volute. A modified volute configuration is examined numerically for further loss comparison.

  15. Failure of action potential propagation in sensory neurons: mechanisms and loss of afferent filtering in C-type units after painful nerve injury.

    Science.gov (United States)

    Gemes, Geza; Koopmeiners, Andrew; Rigaud, Marcel; Lirk, Philipp; Sapunar, Damir; Bangaru, Madhavi Latha; Vilceanu, Daniel; Garrison, Sheldon R; Ljubkovic, Marko; Mueller, Samantha J; Stucky, Cheryl L; Hogan, Quinn H

    2013-02-15

    The T-junction of sensory neurons in the dorsal root ganglion (DRG) is a potential impediment to action potential (AP) propagation towards the CNS. Using intracellular recordings from rat DRG neuronal somata during stimulation of the dorsal root, we determined that the maximal rate at which all of 20 APs in a train could successfully transit the T-junction (following frequency) was lowest in C-type units, followed by A-type units with inflected descending limbs of the AP, and highest in A-type units without inflections. In C-type units, following frequency was slower than the rate at which AP trains could be produced in either dorsal root axonal segments or in the soma alone, indicating that the T-junction is a site that acts as a low-pass filter for AP propagation. Following frequency was slower for a train of 20 APs than for two, indicating that a cumulative process leads to propagation failure. Propagation failure was accompanied by diminished somatic membrane input resistance, and was enhanced when Ca(2+)-sensitive K(+) currents were augmented or when Ca(2+)-sensitive Cl(-) currents were blocked. After peripheral nerve injury, following frequencies were increased in axotomized C-type neurons and decreased in axotomized non-inflected A-type neurons. These findings reveal that the T-junction in sensory neurons is a regulator of afferent impulse traffic. Diminished filtering of AP trains at the T-junction of C-type neurons with axotomized peripheral processes could enhance the transmission of activity that is ectopically triggered in a neuroma or the neuronal soma, possibly contributing to pain generation.

  16. 14 CFR 33.27 - Turbine, compressor, fan, and turbosupercharger rotors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turbine, compressor, fan, and... Turbine, compressor, fan, and turbosupercharger rotors. (a) Turbine, compressor, fan, and... affect turbine, compressor, fan, and turbosupercharger rotor structural integrity will not be exceeded in...

  17. Modeling of surge in free-spool centrifugal compressors : experimental validation

    NARCIS (Netherlands)

    Gravdahl, J.T.; Willems, F.P.T.; Jager, de A.G.; Egeland, O.

    2004-01-01

    The derivation of a compressor characteristic, and the experimental validation of a dynamic model for a variable speed centrifugal compressor using this characteristic, are presented. The dynamic compressor model of Fink et al. is used, and a variable speed compressor characteristic is derived by

  18. Failure analysis of the Ringhals unit 3 EDM surfaces removed from the RPV outlet nozzle to safe end weld

    International Nuclear Information System (INIS)

    Efsing, Pal; Embring, Goeran; Forssgren, Bjoern; Kroes, Bert; Lundstroem, Roger

    2006-09-01

    During the 2000 RFO (Re-Fueling Outage) In-Service Inspection of the nozzle to safe end weld of the Hot Leg Reactor Pressure Vessel Nozzles in Ringhals 3 and 4, axially oriented defects in the Alloy 182 weld metal were detected. In the case of Ringhals 3, the defects were initially considered as being embedded and thus left for future consideration, whereas the defects in Ringhals 4 were judged as being surface breaking and removed by EDM (Electro Discharge Machining). During the RFO 2001, the defects in Ringhals 3 were also removed by EDM without applying any surface treatment subsequent to the sampling. The cavities were inspected using a standard ET technique for manufacturing control before the plant was allowed to return to service. After one cycle of operation, the cavities resulting from the boat sampling were inspected by ET and UT techniques and indications of renewed, shallow cracking were identified. The indications were pre-dominantly axially oriented, of limited depth and with surface breaking lengths varying from 4 to 18 mm. To investigate the cause of this cracking, it was decided to remove a second series of small boat samples from the areas with indications, prior to implementation of a permanent repair. To minimize the impact on the RFO schedule and the material loss that would have resulted from EDM boat sample removal, mini samples were removed manually, using a small axial grinder. The sampling was performed after nozzle decontamination and used a dry nozzle access system that had been specifically developed for the nozzle repair. The sample removal was completed in approximately two hours and a total of three samples were shipped to the Studsvik hot cell laboratories for failure analysis. The failure analysis revealed a typical surface morphology, resulting from the EDM process and confirmed that numerous micro-fissures may result from the process if it is utilized without proper optimization and care. On one of the boat samples, surface areas

  19. Numerical simulation investigation on centrifugal compressor performance of turbocharger

    International Nuclear Information System (INIS)

    Li, Jie; Yin, Yuting; Li, Shuqi; Zhang, Jizhong

    2013-01-01

    In this paper, the mathematical model of the flow filed in centrifugal compressor of turbocharger was studied. Based on the theory of computational fluid dynamics (CFD), performance curves and parameter distributions of the compressor were obtained from the 3-D numerical simulation by using CFX. Meanwhile, the influences of grid number and distribution on compressor performance were investigated, and numerical calculation method was analyzed and validated, through combining with test data. The results obtained show the increase of the grid number has little influence on compressor performance while the grid number of single-passage is above 300,000. The results also show that the numerical calculation mass flow rate of compressor choke situation has a good consistent with test results, and the maximum difference of the diffuser exit pressure between simulation and experiment decrease to 3.5% with the assumption of 6 kPa additional total pressure loss at compressor inlet. The numerical simulation method in this paper can be used to predict compressor performance, and the difference of total pressure ratio between calculation and test is less than 7%, and the total-to-total efficiency also have a good consistent with test.

  20. Core compressor exit stage study. 1: Aerodynamic and mechanical design

    Science.gov (United States)

    Burdsall, E. A.; Canal, E., Jr.; Lyons, K. A.

    1979-01-01

    The effect of aspect ratio on the performance of core compressor exit stages was demonstrated using two three stage, highly loaded, core compressors. Aspect ratio was identified as having a strong influence on compressors endwall loss. Both compressors simulated the last three stages of an advanced eight stage core compressor and were designed with the same 0.915 hub/tip ratio, 4.30 kg/sec (9.47 1bm/sec) inlet corrected flow, and 167 m/sec (547 ft/sec) corrected mean wheel speed. The first compressor had an aspect ratio of 0.81 and an overall pressure ratio of 1.357 at a design adiabatic efficiency of 88.3% with an average diffusion factor or 0.529. The aspect ratio of the second compressor was 1.22 with an overall pressure ratio of 1.324 at a design adiabatic efficiency of 88.7% with an average diffusion factor of 0.491.

  1. Numerical simulation investigation on centrifugal compressor performance of turbocharger

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jie [China Iron and Steel Research Institute Group, Beijing (China); Yin, Yuting [China North Engine Research Institute, Datong (China); Li, Shuqi; Zhang, Jizhong [Science and Technology Diesel Engine Turbocharging Laboratory, Datong (China)

    2013-06-15

    In this paper, the mathematical model of the flow filed in centrifugal compressor of turbocharger was studied. Based on the theory of computational fluid dynamics (CFD), performance curves and parameter distributions of the compressor were obtained from the 3-D numerical simulation by using CFX. Meanwhile, the influences of grid number and distribution on compressor performance were investigated, and numerical calculation method was analyzed and validated, through combining with test data. The results obtained show the increase of the grid number has little influence on compressor performance while the grid number of single-passage is above 300,000. The results also show that the numerical calculation mass flow rate of compressor choke situation has a good consistent with test results, and the maximum difference of the diffuser exit pressure between simulation and experiment decrease to 3.5% with the assumption of 6 kPa additional total pressure loss at compressor inlet. The numerical simulation method in this paper can be used to predict compressor performance, and the difference of total pressure ratio between calculation and test is less than 7%, and the total-to-total efficiency also have a good consistent with test.

  2. Pressure field study of the Tevatron cold compressors

    International Nuclear Information System (INIS)

    Klebaner, A.L.; Martinez, A.; Soyars, W.M.; Theilacker, J.C.; Fermilab

    2003-01-01

    The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, manufactured by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations [1]. The compressor is designed to pump 60 g/sec of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/sec. Operating speeds are between 40 and 95 krpm, with a speed of 80 krpm at the design point. Different heat loads and magnet quench performance of each of the twenty-four satellite refrigerators dictates different process pressure and flow rates of the cold compressors. Reducing the process flow rate can cause the centrifugal cold compressor to stop pumping and subsequently surge. Tests have been conducted at the Cryogenic Test Facility at Fermilab to map the pressure field and appropriate efficiency of the IHI hydrodynamic cold compressor. The information allows tuning of each of the twenty-four Tevatron satellite refrigerators to avoid cold compressor operation near the surge and choke lines. A new impeller has also been tested. The Tevatron cold compressor pressure field and efficiency data with the new impeller are presented in this paper

  3. Pressure Field Study of the Tevatron Cold Compressors

    International Nuclear Information System (INIS)

    Klebaner, A.L.; Martinez, A.; Soyars, W.M.; Theilacker, J.C.

    2004-01-01

    The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, manufactured by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations. The compressor is designed to pump 60 g/sec of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/sec. Operating speeds are between 40,000 and 95,000 rpm, with a speed of 80,000 rpm at the design point. Different heat loads and magnet quench performance of each of the twenty-four satellite refrigerators dictates different process pressure and flow rates of the cold compressors. Reducing the process flow rate can cause the centrifugal cold compressor to stop pumping and subsequently surge. Tests have been conducted at the Cryogenic Test Facility at Fermilab to map the pressure field and appropriate efficiency of the IHI hydrodynamic cold compressor. The information allows tuning of each of the twenty-four Tevatron satellite refrigerators to avoid cold compressor operation near the surge and choke lines. A new impeller has also been tested. The Tevatron cold compressor pressure field and efficiency data with the new impeller are presented in this paper

  4. Surge recovery techniques for the Tevatron cold compressors

    International Nuclear Information System (INIS)

    Martinez, A.; Klebaner, A.L.; Makara, J.N.; Theilacker, J.C.; Fermilab

    2006-01-01

    The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, made by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations [1]. The compressor is designed to pump 60 g/s of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/s and operating speeds between 40 and 95 krpm. Since initial commissioning in 1993, Tevatron transient conditions such as quench recovery have led to multiple-location machine trips as a result of the cold compressors entering the surge regime. Historically, compressors operating at lower inlet pressures and higher speeds have been especially susceptible to these machine trips and it was not uncommon to have multiple compressor trips during large multiple-house quenches. In order to cope with these events and limit accelerator down time, surge recovery techniques have been implemented in an attempt to prevent the compressors from tripping once the machine entered this surge regime. This paper discusses the different methods of surge recovery that have been employed. Data from tests performed at the Cryogenic Test Facility at Fermilab as well as actual Tevatron operational data were utilized. In order to aid in the determination of the surge region, a full mapping study was undertaken to characterize the entire pressure field of the cold compressor. These techniques were then implemented and tested at several locations in the Tevatron with some success

  5. Controlling output pulse and prepulse in a resonant microwave pulse compressor

    International Nuclear Information System (INIS)

    Shlapakovski, A.; Artemenko, S.; Chumerin, P.; Yushkov, Yu.

    2013-01-01

    A resonant microwave pulse compressor with a waveguide H-plane-tee-based energy extraction unit was studied in terms of its capability to produce output pulses that comprise a low-power long-duration (prepulse) and a high-power short-duration part. The application of such combined pulses with widely variable prepulse and high-power pulse power and energy ratios is of interest in the research area of electronic hardware vulnerability. The characteristics of output radiation pulses are controlled by the variation of the H-plane tee transition attenuation at the stage of microwave energy storage in the compressor cavity. Results of theoretical estimations of the parameters tuning range and experimental investigations of the prototype S-band compressor (1.5 MW, 12 ns output pulse; ∼13.2 dB gain) are presented. The achievable maximum in the prepulse power is found to be about half the power of the primary microwave source. It has been shown that the energy of the prepulse becomes comparable with that of the short-duration (nanosecond) pulse, while the power of the latter decreases insignificantly. The possible range of variation of the prepulse power and energy can be as wide as 40 dB. In the experiments, the prepulse level control within the range of ∼10 dB was demonstrated.

  6. Experimental Study for Reduction of Noises and Vibrations in Hermetic Type Compressor

    Science.gov (United States)

    Sano, Kiyoshi; Kawahara, Sadao; Akazawa, Teruyuki; Ishii, Noriaki

    A brushless DC motor with a permanent magnet rotor has been adopted for a scroll compressor for domestic-use air-conditioners because of a demand for compressor high efficiency. A waveform of the driving voltage in the inverter power supply unit is chopped by the PWM signal. Its duty ratio is increased/decreased to control the DC voltage in order to provide a wide range of rotation frequencies for the compressor. The driving voltage includes the carrier frequency and its harmonic components, which produce an electro-magnetic force in the moter, resulting in high electro-magnetic noise. In the present report, the author clarifies the relationships between the noise and the waveform of driving voltage and frequency response function of the motor. A method to improve the frequency response function by changing the stator shape in order to reduce electro-magnetic noise is presented. Subsequently, the influence on electro-magnetic noise from the waveform of driving voltage is examined. Furthermore, the electro-magnetic noises during inverter driving of an induction motor are presented.

  7. Expert system for compressor maintenance support; Sistema especialista para apoio a manutencao de compressores

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jonny Carlos da [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica; Caletti, Luciano [KEOHPS - Knowledge Engineering on Hydraulic and Pneumatic System, SC (Brazil); Luna, Paulo de T.M. [Universidade Regional de Blumenau - FURB, SC (Brazil)

    2004-07-01

    The performance of critical machines in industrial processes, such as compressors used in industrial plants, is fundamental for overall company operation. In this context, it becomes strategic the application of methods and tools to support the operation and maintenance of the most relevant process equipment. Among these computational tools are the Expert Systems, which aim to emulate the decision making process of human experts in a specific knowledge domain. In Oil and Gas domain, an example of such tools is the SEGRED project, which combines expert system techniques with dynamic simulation of transport and distribution natural gas networks. The SECOMP project, Expert System for Compressor Maintenance, is considered a spin-off of the SEGRED. Its objective is to develop an expert system to support maintenance activities, aiming to increase reliability, improve performance and reduce maintenance and operational costs. This article presents the first phase of the SECOMP project, which is related to the development of an expert system prototype for corrective maintenance of natural gas reciprocating compressors. The paper discusses the context of this knowledge domain, the prototype development and its potential contribution in an industrial environment. (author)

  8. An Investigation of Backflow Phenomenon in Centrifugal Compressors

    Science.gov (United States)

    Benser, William A; Moses, Jason J

    1945-01-01

    Report presents the results of an investigation conducted to determine the nature and the extent of the reversal of flow, which occurs at the inlet of centrifugal compressors over a considerable portion of the operating range. Qualitative studies of this flow reversal were made by lampblack patterns taken on a mixed-flow-type impeller and by tuft studies made on a conventional centrifugal compressor. Quantitative studies were made on a compressor specially designed to enable survey of angularity of flow, static and total pressures, and temperatures to be taken very close to the impeller front housing.

  9. Turbine Engine with Differential Gear Driven Fan and Compressor

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Pagluica, Gino J. (Inventor); Duong, Loc Quang (Inventor); Portlock, Lawrence E. (Inventor)

    2013-01-01

    A gas turbine engine provides a differential gear system coupling the turbine to the bypass fan and the compressor. In this manner, the power/speed split between the bypass fan and the compressor can be optimized under all conditions. In the example shown, the turbine drives a sun gear, which drives a planet carrier and a ring gear in a differential manner. One of the planet carrier and the ring gear is coupled to the bypass fan, while the other is coupled to the compressor.

  10. Study of compressor systems for a gas-generator engine

    Science.gov (United States)

    Sather, Bernard I; Tauschek, Max J

    1950-01-01

    Various methods of providing compressor-capacity and pressure-ratio control in the gas-generator type of compound engine over a range of altitudes from sea level to 50,000 feet are presented. The analytical results indicate that the best method of control is that in which the first stage of compression is carried out in a variable-speed supercharger driven by a hydraulic slip coupling. The constant-speed second stage could be either a mixed-flow rotary compressor or a piston-type compressor. A variable-area turbine nozzle is shown to be unnecessary for cruising operation of the engine.

  11. Screw compressor analysis from a vibration point-of-view

    Science.gov (United States)

    Hübel, D.; Žitek, P.

    2017-09-01

    Vibrations are a very typical feature of all compressors and are given great attention in the industry. The reason for this interest is primarily the negative influence that it can have on both the operating staff and the entire machine's service life. The purpose of this work is to describe the methodology of screw compressor analysis from a vibration point-of-view. This analysis is an essential part of the design of vibro-diagnostics of screw compressors with regard to their service life.

  12. Design Method for Channel Diffusers of Centrifugal Compressors

    Directory of Open Access Journals (Sweden)

    Mykola Kalinkevych

    2013-01-01

    Full Text Available The design method for channel diffusers of centrifugal compressors, which is based on the solving of the inverse problem of gas dynamics, is presented in the paper. The concept of the design is to provide high pressure recovery of the diffuser by assuming the preseparation condition of the boundary layer along one of the channel surfaces. The channel diffuser was designed with the use of developed method to replace the vaned diffuser of the centrifugal compressor model stage. The numerical simulation of the diffusers was implemented by means of CFD software. Obtained gas dynamic characteristics of the designed diffuser were compared to the base vaned diffuser of the compressor stage.

  13. Aging of control and service air compressors and dryers used in nuclear power plants

    International Nuclear Information System (INIS)

    Moyers, J.C.

    1990-07-01

    This report was produced under the Detection of Defects and Degradation Monitoring of Nuclear Plant Safety Equipment element of the Nuclear Plant Aging Research Program. This element includes the identification of practical and cost-effective methods for detecting, monitoring, and assessing the severity of time-dependent degradation (aging) of control and service air compressors and dryers in nuclear power plants. These methods are to provide capabilities for establishing degradation trends prior to failure and developing guidance for effective maintenance. The topics of this Phase 1 assessment report are failure modes and causes resulting from aging, manufacturer--recommended maintenance and surveillance practices, and measurable parameters (including functional indicators) for use in assessing operational readiness, establishing degradation trends, and detecting incipient failure. the results presented are based on information derived from operating experience records, manufacturer-supplied information, and input from plant operators. For each failure mode, failure causes are listed by subcomponent, and parameters potentially useful for detecting degradation that could lead to failure are identified. 13 refs., 9 figs., 16 tabs

  14. Performance Characteristics of a Refrigerator-Freezer with Parallel Evaporators using a Linear Compressor

    OpenAIRE

    Min, Byungchae; Song, Sangjin; Noh, Kiyoul; Kim, Geonwoo; Yoon, Teaseung; Na, Sangkyung; Song, Sanghoon; Yang, Jangsik; Choi, Gyungmin; Kim, Duckjool

    2016-01-01

    A linear compressor for a domestic refrigerator-freezer has energy saving potential compared with a reciprocating compressor because of a low friction loss and free piston system. A linear compressor can control the piston stroke since it does not have mechanical restriction of piston movement. Therefore, the energy consumption of a domestic refrigerator-freezer using a linear compressor can be reduced by changing the cooling capacity of the compressor. In order to investigate the performance...

  15. Textiles, Guano and Railroads: The Role of the United States in the Early Development Failures of Peru, 1818-1876

    OpenAIRE

    Bollinger, William

    2012-01-01

    Peru's importance to the United States in the nineteenth century has been underappreciated because there were few instances of sharp conflict between the two nations. But, beginning with U.S. export of coarse cloth from new cotton mills just after Peruvian independence, continuing during the influence of Peruvian guano on U.S. "scientific agriculture," and then in the period of Peru's extraordinary effort to build trans-Andean railways, Peru exercised important influence on U.S. economy and ...

  16. Retrofitting reciprocating compressors for noise control

    International Nuclear Information System (INIS)

    Frank, L.; Qualfe, R.

    1992-01-01

    The Alberta Energy Resources Conservation Board recently enacted their noise control directive ID 88-1. The effects of this regulation on the operation of an oil and gas facility are discussed, and a specific case history is presented to provide a disciplined strategy for noise attenuation retrofits. An investigation was carried out into sound sources at a reciprocating compressor gas plant, revealing several sound sources: engine exhaust stacks, engine exhaust silencer shells, direct-drive fan cooler inlets, direct drive fan cooler outlets, aerial cooler inlets and aerial cooler outlets. Details are presented of the investigative techniques and order-ranking of sources by decibel level. When controlling engine exhaust noise, silencers or mufflers are the preferred treatment. Choice of type (reactive or absorptive) and specification of acoustical performance of a silencer are discussed. The gas plant achieved noise reductions of 6-13 dB, measured at affected residences, through the use of engine exhaust silencers. 4 figs., 2 tabs

  17. Gas turbine engine with supersonic compressor

    Science.gov (United States)

    Roberts, II, William Byron; Lawlor, Shawn P.

    2015-10-20

    A gas turbine engine having a compressor section using blades on a rotor to deliver a gas at supersonic conditions to a stator. The stator includes one or more of aerodynamic ducts that have converging and diverging portions for deceleration of the gas to subsonic conditions and to deliver a high pressure gas to combustors. The aerodynamic ducts include structures for changing the effective contraction ratio to enable starting even when designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of two to one (2:1) or more, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

  18. Demonstration of PIV in a Transonic Compressor

    Science.gov (United States)

    Wernet, Mark P.

    1998-01-01

    Particle Imaging Velocimetry (PIV) is a powerful measurement technique which can be used as an alternative or complementary approach to Laser Doppler Velocimetry (LDV) in a wide range of research applications. PIV data are measured simultaneously at multiple points in space, which enables the investigation of the non-stationary spatial structures typically encountered in turbomachinery. Many of the same issues encountered in the application of LDV techniques to rotating machinery apply in the application of PIV. Preliminary results from the successful application of the standard 2-D PIV technique to a transonic axial compressor are presented. The lessons learned from the application of the 2-D PIV technique will serve as the basis for applying 3-component PIV techniques to turbomachinery.

  19. Coatings for Fuel Cell Propulsion Compressor Bearings, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Fuel cell air handling systems require clean and contaminant-free inlet air, which dictates that oil-free, motorized, compressor/expander systems should be used....

  20. Virtual Training of Compressor Control Room, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — MYMIC will analyze, design, develop and evaluate the Virtual Control Room – Compressor Station (VCoR-CS) training system. VCoR-CS will provide procedural training to...

  1. Vapor Compressor Driven Hybrid Two-Phase Loop, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will demonstrate a vapor compressor driven hybrid two-phase loop technology. The hybrid two-phase loop...

  2. Development of throughflow calculation code for axial flow compressors

    International Nuclear Information System (INIS)

    Kim, Ji Hwan; Kim, Hyeun Min; No, Hee Cheon

    2005-01-01

    The power conversion systems of the current HTGRs are based on closed Brayton cycle and major concern is thermodynamic performance of the axial flow helium gas turbines. Particularly, the helium compressor has some unique design challenges compared to the air-breathing compressor such as high hub-to-tip ratios throughout the machine and a large number of stages due to the physical property of the helium and thermodynamic cycle. Therefore, it is necessary to develop a design and analysis code for helium compressor that can estimate the design point and off-design performance accurately. KAIST nuclear system laboratory has developed a compressor design and analysis code by means of throughflow calculation and several loss models. This paper presents the outline of the development of a throughflow calculation code and its verification results

  3. Development Of A Centrifugal Hydrogen Pipeline Gas Compressor

    Energy Technology Data Exchange (ETDEWEB)

    Di Bella, Francis A. [Concepts NREC, White River Junction, VY (United States)

    2015-04-16

    Concepts NREC (CN) has completed a Department of Energy (DOE) sponsored project to analyze, design, and fabricate a pipeline capacity hydrogen compressor. The pipeline compressor is a critical component in the DOE strategy to provide sufficient quantities of hydrogen to support the expected shift in transportation fuels from liquid and natural gas to hydrogen. The hydrogen would be generated by renewable energy (solar, wind, and perhaps even tidal or ocean), and would be electrolyzed from water. The hydrogen would then be transported to the population centers in the U.S., where fuel-cell vehicles are expected to become popular and necessary to relieve dependency on fossil fuels. The specifications for the required pipeline hydrogen compressor indicates a need for a small package that is efficient, less costly, and more reliable than what is available in the form of a multi-cylinder, reciprocating (positive displacement) compressor for compressing hydrogen in the gas industry.

  4. 40 CFR 61.242-3 - Standards: Compressors.

    Science.gov (United States)

    2010-07-01

    ... at a pressure that is greater than the compressor stuffing box pressure; or (2) Equipped with a...) Equipped with a system that purges the barrier fluid into a process stream with zero VHAP emissions to...

  5. 40 CFR 60.482-3a - Standards: Compressors.

    Science.gov (United States)

    2010-07-01

    ...) Operated with the barrier fluid at a pressure that is greater than the compressor stuffing box pressure; or... § 60.482-10a; or (3) Equipped with a system that purges the barrier fluid into a process stream with...

  6. Computational Analysis of Flow Through a Transonic Compressor Rotor

    National Research Council Canada - National Science Library

    Bochette, Nikolaus J

    2005-01-01

    .... In examining this problem two Computational Fluid Dynamic (CFD) codes have been used by the Naval Postgraduate School to predict the performance of a transonic compressor rotor that is being tested with steam ingestion...

  7. Small variable speed hermetic reciprocating compressors for domestic refrigerators

    DEFF Research Database (Denmark)

    Rasmussen, Bjarne D.

    1996-01-01

    This paper contains both a theoretical and experimental investigation of some of the fundamental characteristics of a smal variable speed hermetic reciprocating compressor intended for application in domestic refrigeration. The results of a previously published simulation model for variable speed...

  8. Numerical research on the scroll compressor with refrigeration injection

    International Nuclear Information System (INIS)

    Wang Baolong; Shi Wenxing; Li Xianting; Yan Qisen

    2008-01-01

    A general model for a scroll compressor with refrigerant injection is established in this paper. The model can be used to predict the macro performance and inner compression process of the injected scroll compressor. A series of experiments are conducted to validate the accuracy of the model. The results show that the model can precisely predict not only the general performance of the compressor but also the inner compression with or without refrigerant injection. Based on the thermodynamic model and the test bench, the injection process of the scroll compressor has been investigated and the thermodynamic essence is revealed. It is found that the refrigerant injection process can be considered as a continual parameter-varying 'adiabatic throttling + isobaric mixture' time-varying process

  9. Compensating effect of the coherent synchrotron radiation in bunch compressors

    Science.gov (United States)

    Jing, Yichao; Hao, Yue; Litvinenko, Vladimir N.

    2013-06-01

    Typical bunch compression for a high-gain free-electron laser (FEL) requires a large compression ratio. Frequently, this compression is distributed in multiple stages along the beam transport line. However, for a high-gain FEL driven by an energy recovery linac (ERL), compression must be accomplished in a single strong compressor located at the beam line’s end; otherwise the electron beam would be affected severely by coherent synchrotron radiation (CSR) in the ERL’s arcs. In such a scheme, the CSR originating from the strong compressors could greatly degrade the quality of the electron beam. In this paper, we present our design for a bunch compressor that will limit the effect of CSR on the e-beam’s quality. We discuss our findings from a study of such a compressor, and detail its potential for an FEL driven by a multipass ERL developed for the electron-Relativistic Heavy Ion Collider.

  10. WWER identification and analysis of dominant factors affecting the fuel failure rates in WWER-1000 units in Czech Republic, Bulgaria, Ukraine and Russia

    International Nuclear Information System (INIS)

    Evdokimov, I.; Likhanskii, V.; Afanasieva, E.; Kanukova, V.; Kozhakin, A.; Maslova, L.; Chernetskiy, M.; Zborovskii, V.; Sorokin, A.

    2015-01-01

    The paper reviews the major findings of the study in the frame of the “Zero Failure Rate” project for WWER. The study included analysis and systematization of available data on leaking fuel assemblies found in 2003 through 2014 in WWER-1000 nuclear units in Russia, Ukraine, Czech Republic and Bulgaria. The study was intended to be used in preparation of recommendations and elaboration of corrective measures for enhancement of reliability and decrease of the failure rates for the WWER-1000 fuel. One of the key areas in successful implementation of the industry ‘zero failure’ goal is a challenge of significant increase of inspections of WWER-1000 fuel assemblies. It may be reasonable (with account taken for international experience) to think of development of more effective equipment for prompt fuel inspections & repair in WWER-1000 spent fuel pool. Another challenge is the elaboration of unified fuel inspection guidelines to ensure that limited industry resources are spent in the most productive way. In the frame of this work it may be helpful to implement in practice the criteria for safe removal of defective fuel rods from the leaking FA under repair

  11. Hubungan antara Rasio Neutrofil-Limfosit dan Skor Sequencial Organ Failure Assesment pada Pasien yang Dirawat di Ruang Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Adi Nugroho

    2013-12-01

    Full Text Available Physiological response of immune system against systemic inflammation involves an increased level of neutrophils and a reduction of lymphocyte or an increase of neutrophil-lymphocyte ratio (RNL. The aim of this study was to identify the relationship between systemic inflammation, characterized by increasing in RNL on organ malfunction, assessed by Sequential Organ Failure Assessment (SOFA score in Intensive Care Unit (ICU patients. This study was a observational study with cross sectional design. This study was conducted by observing RNL and SOFA score at 0, 24th and 48th hour of 78 patients treated in the ICU Dr. Hasan Sadikin General Hospital Bandung in December 2012–February 2013. Patients were divided into 3 categories of sepsis A, B and C. This study showed that there was a relationship between RNL, SOFA scores and sepsis categories (p<0.001. Pearson Correlation Test showed that there was relationship between RNL and SOFA scores (p<0.05, R= 0.63. In conclusion, there is a relationship between systemic inflammatory condition, characterized by RNL and organ failure, characterized by the SOFA score, in patients treated in the ICU Dr. Hasan Sadikin General Hospital Bandung

  12. The Study of Vibration Processes in Oil Flooded Screw Compressors

    Directory of Open Access Journals (Sweden)

    I. V. Filippov

    2014-01-01

    Full Text Available Vibration processes that accompany most of machines and mechanisms are of interest to the researcher, as a source of information about the technical condition and the nature of the business processes flow. Vibration-based diagnostics of oil flooded screw compressors allows us to estimate the deviation of their operation from the main mode in accordance with changing the settings of vibration processes.The oil flooded screw compressor transition from the main mode of operation to the abnormal one is accompanied by complex gas-dynamic phenomena i.e. the initial gaps and their decays. This leads to changes in the nature of vibration processes, prompting suggestions that there is a relationship to a change of vibration parameters and mode of compressor operation.Studies were conducted by combined method using an analytical calculation of the decay parameters of the initial discontinuity and an experimental one based on the measurement of acceleration on the body of the real oil flooded screw compressor. A virtually adequate reaction of the decay parameters of the initial gap and the peak values of vibration acceleration to the change of operation mode of oil flooded screw compressor has been received. The peak value of the vibration acceleration was selected by the method of Gating being time-coinciding with the beginning discharge phase of the oil flooded screw compressor, and therefore, with the decay time of the initial discontinuity.This indicates a large degree of hypothesis likelihood on an existing initial break in oil flooded screw compressor when operating in abnormal conditions. This work contains the study results of vibration processes and their relationship to the operating mode of the oil flooded screw compressor, which distinguish it from the other works studied vibration processes in reciprocating compressors. The vibration parameters control of operating oil flooded screw compressor allows us to create an automatic capacity control

  13. Investigation of the compressor part-load behaviour and its effects on the per annum energy consumption of the air conditioner; Untersuchung des Kompressor-Teillastverhaltens im Hinblick auf den Jahresverbrauch der Klimaanlage

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Klaus; Lechner, Bernhard [Virtual Vehicle. Kompetenzzentrum - Das virtuelle Fahrzeug Forschungsgesellschaft mbH (ViF), Graz (Austria); Rieberer, Rene [Technische Univ. Graz (Austria); Moenkediek, Thomas [Audi AG, Ingolstadt (Germany)

    2010-07-01

    The air conditioning system is one of the most important ancillary units of a motor vehicle. Energetic optimization of air conditioners has been a key issue of research at AUDI AG during the past few years. As a rule, the cooling capacity of the air conditioner is controlled by adapting the compressor lift if the compressor is driven by the car engine and control via the rotational speed is not possible. As air conditioners ted to be designed for extreme conditions, the compressor will work at part load in most operating conditions. Optimization of the energetic efficiency of the air conditioner also means to look at the part-load behaviour of the compressor. Simulations have been used successfully by AUDI AG for many years now; the have helped to shorten development times and improve the product quality. The contribution describes an advanced model of a swivel plate compressor of a R134a cooling cycle with particular consideration of part-lift operation. The simulation model is based on measurements with continous recording of the piston lift. The focus is on the influence of reduced lift on the compressor efficiency. Another point of interest is the successful integration of the compressor model in the overall refrigerating cycle model which will be used for simulations of system performance and efficiency and for further optimization of the air conditioner. (orig.)

  14. Compressor with pump recycling for isotopic separation through gaseous scattering

    International Nuclear Information System (INIS)

    Plotkowiak, J.; Quillevere, H.A.

    1984-01-01

    A compressor which compresses a principal flow at low pressure and recompresses a secondary flow at medium pressure to deliver a common flow at high pressure is disclosed. The compressor includes, in addition to compression devices for the principal flow, static devices forming an induction nozzle housed in the scatterer and devices to introduce therein the secondary flow, the principal flow constituting the drive flow

  15. Control optimization of the cryoplant warm compressor station for EAST

    International Nuclear Information System (INIS)

    Zhuang, M.; Hu, L. B.; Zhou, Z. W.; Xia, G. H.

    2014-01-01

    The cryogenic control system for EAST (Experimental Advanced Superconducting Tokamak) was designed based on DeltaV DCS of Emerson Corporation. The automatic control of the cryoplant warm compressors has been implemented. However, with ever-degrading performance of critical equipment, the cryoplant operation in the partial design conditions makes the control system fluctuate and unstable. In this paper, the warm compressor control system was optimized to eliminate the pressure oscillation based on the expert PID theory

  16. Hyper dispersion pulse compressor for chirped pulse amplification systems

    Science.gov (United States)

    Barty, Christopher P. J.

    2011-11-29

    A grating pulse compressor configuration is introduced for increasing the optical dispersion for a given footprint and to make practical the application for chirped pulse amplification (CPA) to quasi-narrow bandwidth materials, such as Nd:YAG. The grating configurations often use cascaded pairs of gratings to increase angular dispersion an order of magnitude or more. Increased angular dispersion allows for decreased grating separation and a smaller compressor footprint.

  17. Experimental Study on Noise Characteristic of Centrifugal Compressor Surge

    OpenAIRE

    Yang, Qichao; Zhao, Yuanyang; SHU, Yue; LI, Xiaosa; LI, Liansheng

    2016-01-01

    The centrifugal air compressor test rig is was designed and established. The experimental study was carried out on the surge characteristics of centrifugal compressor including the pressure in the pipe and the noise characteristics under different rotation speed. The tested results showed that both the suction pressure and discharge pressure fluctuation increase under surge condition and the amplitude of discharge pressure fluctuation is significantly higher than that of suction pressure. In ...

  18. Internal combustion engine for natural gas compressor operation

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, Christopher; Babbitt, Guy

    2016-12-27

    This application concerns systems and methods for compressing natural gas with an internal combustion engine. In a representative embodiment, a method is featured which includes placing a first cylinder of an internal combustion engine in a compressor mode, and compressing a gas within the first cylinder, using the cylinder as a reciprocating compressor. In some embodiments a compression check valve system is used to regulate pressure and flow within cylinders of the engine during a compression process.

  19. Maintenance problems on reciprocating compressors [Paper No.: VA-3

    International Nuclear Information System (INIS)

    Lakshminarayan, S.

    1981-01-01

    The Heavy Water Plant at Baroda has a number of reciprocting compressors for handling synthesis gas, refrigeration ammonia and air for instrumentation. As these compressors are running continuously, their parts are subjected to wear and tear. Problems generally come up in bearings, valves, stuffing box packings, piston rings and similar such components. These problems and methods of tackling them are discussed. (M.G.B.)

  20. ADVANCED COMPRESSOR ENGINE CONTROLS TO ENHANCE OPERATION, RELIABILITY AND INTEGRITY

    Energy Technology Data Exchange (ETDEWEB)

    Gary D. Bourn; Jess W. Gingrich; Jack A. Smith

    2004-03-01

    This document is the final report for the ''Advanced Compressor Engine Controls to Enhance Operation, Reliability, and Integrity'' project. SwRI conducted this project for DOE in conjunction with Cooper Compression, under DOE contract number DE-FC26-03NT41859. This report addresses an investigation of engine controls for integral compressor engines and the development of control strategies that implement closed-loop NOX emissions feedback.

  1. Opposed piston linear compressor driven two-stage Stirling Cryocooler for cooling of IR sensors in space application

    Science.gov (United States)

    Bhojwani, Virendra; Inamdar, Asif; Lele, Mandar; Tendolkar, Mandar; Atrey, Milind; Bapat, Shridhar; Narayankhedkar, Kisan

    2017-04-01

    A two-stage Stirling Cryocooler has been developed and tested for cooling IR sensors in space application. The concept uses an opposed piston linear compressor to drive the two-stage Stirling expander. The configuration used a moving coil linear motor for the compressor as well as for the expander unit. Electrical phase difference of 80 degrees was maintained between the voltage waveforms supplied to the compressor motor and expander motor. The piston and displacer surface were coated with Rulon an anti-friction material to ensure oil less operation of the unit. The present article discusses analysis results, features of the cryocooler and experimental tests conducted on the developed unit. The two-stages of Cryo-cylinder and the expander units were manufactured from a single piece to ensure precise alignment between the two-stages. Flexure bearings were used to suspend the piston and displacer about its mean position. The objective of the work was to develop a two-stage Stirling cryocooler with 2 W at 120 K and 0.5 W at 60 K cooling capacity for the two-stages and input power of less than 120 W. The Cryocooler achieved a minimum temperature of 40.7 K at stage 2.

  2. Multi-Temperature Heat Pump with Cascade Compressor Connection

    Directory of Open Access Journals (Sweden)

    Sit M.L.

    2017-08-01

    Full Text Available The object of the study is a multifunctional heat pump with several evaporators and condensers designed for simultaneous provision of technological processes with heat and cold. The aim of the work is the development and study of the scheme for this type of heat pumps, which ensures minimum irreversibility in the "compressor-gas coolers" chain, without the use of adjustable ejectors installed after evaporators and used as flow mixers. The obtained technical solution ensures the stabilization of the heat pump coefficient of performance (COP and prescribed thermal regimes of heat exchangers at a variable flow rate of the refrigerant. The novelty of the elaboration is inclusion a compressor of the first stage with a serially connected intermediate heat exchanger and a control valve that are located before the compressor inlet of the second stage of the heat pump, which allows to establish a rational pressure after the first stage of the compressors. A scheme is proposed for regulating the temperature at the inlet of the first stage compressors by regulating the flow through the primary circuits of the recuperative heat exchangers. The first stage compressor control system allows providing the required modes of operation of the heat pump. It is established, because of the exergetic analysis of the sections of the hydraulic circuit of heat pump located between the evaporators and gas coolers that the reduction of irreversible losses in the heat pump is ensured due to the optimal choice of the superheat value of the gas after the evaporators.

  3. Towards Large Eddy Simulation of gas turbine compressors

    Science.gov (United States)

    McMullan, W. A.; Page, G. J.

    2012-07-01

    With increasing computing power, Large Eddy Simulation could be a useful simulation tool for gas turbine axial compressor design. This paper outlines a series of simulations performed on compressor geometries, ranging from a Controlled Diffusion Cascade stator blade to the periodic sector of a stage in a 3.5 stage axial compressor. The simulation results show that LES may offer advantages over traditional RANS methods when off-design conditions are considered - flow regimes where RANS models often fail to converge. The time-dependent nature of LES permits the resolution of transient flow structures, and can elucidate new mechanisms of vorticity generation on blade surfaces. It is shown that accurate LES is heavily reliant on both the near-wall mesh fidelity and the ability of the imposed inflow condition to recreate the conditions found in the reference experiment. For components embedded in a compressor this requires the generation of turbulence fluctuations at the inlet plane. A recycling method is developed that improves the quality of the flow in a single stage calculation of an axial compressor, and indicates that future developments in both the recycling technique and computing power will bring simulations of axial compressors within reach of industry in the coming years.

  4. The New Performance Calculation Method of Fouled Axial Flow Compressor

    Directory of Open Access Journals (Sweden)

    Huadong Yang

    2014-01-01

    Full Text Available Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. In the previous research, it is very difficult to accurately model the fouled axial flow compressor. This paper develops a new performance calculation method of fouled multistage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. The first section includes the first 50% stages which reflect the fouling level, and the second section includes the last 50% stages which are viewed as the clean stage because of less deposits. In this model, the performance of the first section is obtained by combining scaling law method and linear progression model with traditional stage stacking method; simultaneously ambient conditions and engine configurations are considered. On the other hand, the performance of the second section is calculated by averaged infinitesimal stage method which is based on Reynolds’ law of similarity. Finally, the model is successfully applied to predict the 8-stage axial flow compressor and 16-stage LM2500-30 compressor. The change of thermodynamic parameters such as pressure ratio, efficiency with the operating time, and stage number is analyzed in detail.

  5. Prediction of active control of subsonic centrifugal compressor rotating stall

    Science.gov (United States)

    Lawless, Patrick B.; Fleeter, Sanford

    1993-01-01

    A mathematical model is developed to predict the suppression of rotating stall in a centrifugal compressor with a vaned diffuser. This model is based on the employment of a control vortical waveform generated upstream of the impeller inlet to damp weak potential disturbances that are the early stages of rotating stall. The control system is analyzed by matching the perturbation pressure in the compressor inlet and exit flow fields with a model for the unsteady behavior of the compressor. The model was effective at predicting the stalling behavior of the Purdue Low Speed Centrifugal Compressor for two distinctly different stall patterns. Predictions made for the effect of a controlled inlet vorticity wave on the stability of the compressor show that for minimum control wave magnitudes, on the order of the total inlet disturbance magnitude, significant damping of the instability can be achieved. For control waves of sufficient amplitude, the control phase angle appears to be the most important factor in maintaining a stable condition in the compressor.

  6. Impact of inlet coherent motions on compressor performance

    Science.gov (United States)

    Forlese, Jacopo; Spoleti, Giovanni

    2017-08-01

    Automotive engine induction systems may be characterized by significant flow angularity and total pressure distortion at the compressor inlet. The impact of the swirl on compressor performance should be quantified to guide the design of the induction systems. In diesel engines, the presence of a valve for flow reduction and control of low pressure EGR recirculation could generate coherent motion and influence the performance of the compressor. Starting from experimental map, the compressor speed-lines have been simulated using a 3D CFD commercial code imposing different concept motion at the inlet. The swirl intensity, the direction and the number of vortices have been imposed in order to taking into account some combinations. Finally, a merit function has been defined to evaluate the performance of the compressor with the defined swirl concepts. The aim of the current work is to obtain an indication on the effect of a swirling motion at the compressor inlet on the engine performance and provide a guideline to the induction system design.

  7. Insulation system in an integrated motor compressor

    Energy Technology Data Exchange (ETDEWEB)

    Sihvo, V.

    2010-07-01

    A high-speed and high-voltage solid-rotor induction machine provides beneficial features for natural gas compressor technology. The mechanical robustness of the machine enables its use in an integrated motor-compressor. The technology uses a centrifugal compressor, which is mounted on the same shaft with the high-speed electrical machine driving it. No gearbox is needed as the speed is determined by the frequency converter. The cooling is provided by the process gas, which flows through the motor and is capable of transferring the heat away from the motor. The technology has been used in the compressors in the natural gas supply chain in the central Europe. New areas of application include natural gas compressors working at the wellheads of the subsea gas reservoir. A key challenge for the design of such a motor is the resistance of the stator insulation to the raw natural gas from the well. The gas contains water and heavy hydrocarbon compounds and it is far harsher than the sales gas in the natural gas supply network. The objective of this doctoral thesis is to discuss the resistance of the insulation to the raw natural gas and the phenomena degrading the insulation. The presence of partial discharges is analyzed in this doctoral dissertation. The breakdown voltage of the gas is measured as a function of pressure and gap distance. The partial discharge activity is measured on small samples representing the windings of the machine. The electrical field behavior is also modeled by finite element methods. Based on the measurements it has been concluded that the discharges are expected to disappear at gas pressures above 4 - 5 bar. The disappearance of discharges is caused by the breakdown strength of the gas, which increases as the pressure increases. Based on the finite element analysis, the physical length of a discharge seen in the PD measurements at atmospheric pressure was approximated to be 40 - 120 mum. The chemical aging of the insulation when exposed to raw

  8. Fermilab satellite refrigerator compressors with the oil- and moisture-removal systems

    International Nuclear Information System (INIS)

    Satti, J.A.; Andrews, R.A.

    1983-08-01

    We have designed and tested a helium purification system for the Energy Doubler and the experimental areas. A purification system is installed after each screw compressor in the satellite refrigerators. The purification system removes oil mist, oil vapor, water vapor, and particulate from the compressed helium. The units were designed with consideration of modularity and necessary redundancy (i.e., guard purification). Test results which led to the final configuration are presented, along with achieved performance of the oil removal in the operating system

  9. Central oxygen pipeline failure

    African Journals Online (AJOL)

    surgical intensive care unit (ICU), with two patients on full ventilation and ... uncertainty around the cause of the failure and the restoration, .... soon as its level also falls below three tons. Should ... (properly checked and closed prior to each anaesthetic). ... in use at the time of the central oxygen pipeline failure at Tygerberg.

  10. Managing Postoperative Analgesic Failure: Tramadol Versus Morphine for Refractory Pain in the Post-Operative Recovery Unit.

    Science.gov (United States)

    Byrne, Kelly; Nolan, Aoife; Barnard, John; Tozer, Megan; Harris, David; Sleigh, Jamie

    2017-02-01

    This study aimed to discover whether co-analgesia with tramadol or additional morphine was more effective for patients who still had severe pain despite being given 10 mg intravenous morphine in the post-anesthesia care unit (PACU). All eligible patients were consented and recruited to the trial pre-operatively, but only a small subgroup – whose pain was not successfully controlled (pain score 6/10 or more) after receiving 10 mg of morphine in the PACU—were then randomized to enter the trial and receive, in a double blinded fashion, the analgesic study drug; which consisted of either a further 10 mg of morphine, or 100 mg of tramadol, titrated intravenously to control their pain. The groups were compared as to: the time to readiness for discharge, the patient’s pain scores over time, and the presence of side effects. There was no statistically significant difference in any of the outcomes measured. The time to readiness for discharge from PACU was 119 minutes in the morphine group and 120 minutes in the tramadol group. However in approximately half the cases who entered the trial (i.e., where pain had not been controlled with the pre-enrollment baseline 10 mg of morphine in PACU) neither a further 10 mg of morphine nor 100 mg of tramadol effectively relieved the patient’s pain. We found no difference between additional morphine and co-analgesia with tramadol in this study. Patients who don’t respond to reasonable doses of opioids in PACU are very likely to be unresponsive to further opioids, and other non-opioid analgesic techniques (such as regional anesthesia) should be considered early in this group of patients.

  11. Increase of Gas-Turbine Plant Efficiency by Optimizing Operation of Compressors

    Science.gov (United States)

    Matveev, V.; Goriachkin, E.; Volkov, A.

    2018-01-01

    The article presents optimization method for improving of the working process of axial compressors of gas turbine engines. Developed method allows to perform search for the best geometry of compressor blades automatically by using optimization software IOSO and CFD software NUMECA Fine/Turbo. The calculation of the compressor parameters was performed for work and stall point of its performance map on each optimization step. Study was carried out for seven-stage high-pressure compressor and three-stage low-pressure compressors. As a result of optimization, improvement of efficiency was achieved for all investigated compressors.

  12. Small axial compressor technology, volume 1

    Science.gov (United States)

    Holman, F. F.; Kidwell, J. R.; Ware, T. C.

    1976-01-01

    A scaled single-stage, highly-loaded, axial-flow transonic compressor was tested at speeds from 70 to 110% design equivalent speed to evaluate the effects of scaling compromises and the individual and combined effects of rotor tip running clearance and rotor shroud casing treatment on the overall and blade element performance. At design speed and 1% tip clearance the stage demonstrated an efficiency of 83.2% at 96.4% design flow and a pressure ratio of 1.865. Casing treatment increased design speed surge margin 2.0 points to 12.8%. Overall performance was essentially unchanged. An increase in rotor running clearance to 2.2%, with smooth casing, reduced design speed peak efficiency 5.7 points, flow by 7.4%, pressure ratio to 1.740, and surge margin to 5.4%. Reinstalling casing treatment regained 3.5 points in design speed peak efficiency, 4.7% flow, increased pressure ratio to 1.800 and surge margin to 8.7%.

  13. Wave Augmented Diffuser for Centrifugal Compressor

    Science.gov (United States)

    Skoch, Gary J. (Inventor); Paxson, Daniel E. (Inventor)

    2001-01-01

    A wave augmented diffuser for a centrifugal compressor surrounds the outlet of an impeller that rotates on a drive shaft having an axis of rotation. The impeller brings flow in in an axial direction and imparts kinetic energy to the flow discharging it in radial and tangential directions. The flow is discharged into a plurality of circumferentially disposed wave chambers. The wave chambers are periodically opened and closed by a rotary valve such that the flow through the diffuser is unsteady. The valve includes a plurality of valve openings that are periodically brought into and out of fluid communication with the wave chambers. When the wave chambers are closed, a reflected compression wave moves upstream towards the diffuser bringing the flow into the wave chamber to rest. This action recovers the kinetic energy from the flow and limits any boundary layer growth. The flow is then discharged in an axial direction through an opening in the valve plate when the valve plate is rotated to an open position. The diffuser thus efficiently raises the static pressure of the fluid and discharges an axially directed flow at a radius that is predominantly below the maximum radius of the diffuser.

  14. Wave Augmented Diffusers for Centrifugal Compressors

    Science.gov (United States)

    Paxson, Daniel E.; Skoch, Gary J.

    1998-01-01

    A conceptual device is introduced which would utilize unsteady wave motion to slow and turn flows in the diffuser section of a centrifugal compressor. The envisioned device would substantially reduce the size of conventional centrifugal diffusers by eliminating the relatively large ninety degree bend needed to turn the flow from the radial/tangential to the axial direction. The bend would be replaced by a wall and the flow would instead exit through a series of rotating ports located on a disk, adjacent to the diffuser hub, and fixed to the impeller shaft. The ports would generate both expansion and compression waves which would rapidly transition from the hub/shroud (axial) direction to the radial/tangential direction. The waves would in turn induce radial/tangential and axial flow. This paper presents a detailed description of the device. Simplified cycle analysis and performance results are presented which were obtained using a time accurate, quasi-one-dimensional CFD code with models for turning, port flow conditions, and losses due to wall shear stress. The results indicate that a periodic wave system can be established which yields diffuser performance comparable to a conventional diffuser. Discussion concerning feasibility, accuracy, and integration follow.

  15. Variation in critical care unit admission rates and outcomes for patients with acute coronary syndromes or heart failure among high- and low-volume cardiac hospitals.

    Science.gov (United States)

    van Diepen, Sean; Bakal, Jeffrey A; Lin, Meng; Kaul, Padma; McAlister, Finlay A; Ezekowitz, Justin A

    2015-02-27

    Little is known about cross-hospital differences in critical care units admission rates and related resource utilization and outcomes among patients hospitalized with acute coronary syndromes (ACS) or heart failure (HF). Using a population-based sample of 16,078 patients admitted to a critical care unit with a primary diagnosis of ACS (n=14,610) or HF (n=1467) between April 1, 2003 and March 31, 2013 in Alberta, Canada, we stratified hospitals into high (>250), medium (200 to 250), or low (<200) volume based on their annual volume of all ACS and HF hospitalization. The percentage of hospitalized patients admitted to critical care units varied across low, medium, and high-volume hospitals for both ACS and HF as follows: 77.9%, 81.3%, and 76.3% (P<0.001), and 18.0%, 16.3%, and 13.0% (P<0.001), respectively. Compared to low-volume units, critical care patients with ACS and HF admitted to high-volume hospitals had shorter mean critical care stays (56.6 versus 95.6 hours, P<0.001), more critical care procedures (1.9 versus 1.2 per patient, <0.001), and higher resource-intensive weighting (2.8 versus 1.5, P<0.001). No differences in in-hospital mortality (5.5% versus 6.2%, adjusted odds ratio 0.93; 95% CI, 0.61 to 1.41) were observed between high- and low-volume hospitals; however, 30-day cardiovascular readmissions (4.6% versus 6.8%, odds ratio 0.77; 95% CI, 0.60 to 0.99) and cardiovascular emergency-room visits (6.6% versus 9.5%, odds ratio 0.80; 95% CI, 0.69 to 0.94) were lower in high-volume compared to low-volume hospitals. Outcomes stratified by ACS or HF admission diagnosis were similar. Cardiac patients hospitalized in low-volume hospitals were more frequently admitted to critical care units and had longer hospitals stays despite lower resource-intensive weighting. These findings may provide opportunities to standardize critical care utilization for ACS and HF patients across high- and low-volume hospitals. © 2015 The Authors. Published on behalf of the American

  16. Aging and service wear of air compressors and dryers in nuclear power plants

    International Nuclear Information System (INIS)

    Moyers, J.C.

    1989-01-01

    Compressed air systems and their associated compressors and dryers as incorporated in LWR power plants usually are not classified as safety related systems and components because their continued operation is not required to bring the plant to a safe shutdown condition. However, control air is a vital requirement for maintaining stable plant operation and its loss often results in a reactor trip and, on occasion, the actuation of engineered safety feature systems. Concerns caused by repeated instances of failures in air systems resulted in the high-priority ranking of Generic Issue No. 43, ''Reliability of Air Systems'' by the NRC. In support of the Nuclear Plant Aging Research (NPAR) Program, the Oak Ridge National Laboratory is carrying out a Phase I aging assessment of air compressors and dryers used in LWR power plants. The objectives of this study include: (1) determination of the types and ratings of equipment utilized in typical plants; (2) identification of aging and service wear stressors imposed on the machines; (3) evaluation of operating experience with the machines; (4) comparison of user and manufacturer-recommended inspection, surveillance, and monitoring (ISM) methods; and (5) the identification of any improved ISM methods that might lead to longer, more reliable, service. 2 refs

  17. NASA Glenn's Single-Stage Axial Compressor Facility Upgraded

    Science.gov (United States)

    Brokopp, Richard A.

    2004-01-01

    NASA Glenn Research Center's Single-Stage Axial Compressor Facility was upgraded in fiscal year 2003 to expand and improve its research capabilities for testing high-speed fans and compressors. The old 3000-hp drive motor and gearbox were removed and replaced with a refurbished 7000-hp drive motor and gearbox, with a maximum output speed of 21,240 rpm. The higher horsepower rating permits testing of fans and compressors with higher pressure ratio or higher flow. A new inline torquemeter was installed to provide an alternate measurement of fan and compressor efficiency, along with the standard pressure and temperature measurements. A refurbished compressor bearing housing was also installed with bidirectional rotation capability, so that a variety of existing hardware could be tested. Four new lubrication modules with backup capability were installed for the motor, gearbox, torquemeter, and compressor bearing housing, so that in case the primary pump fails, the backup will prevent damage to the rotating hardware. The combustion air supply line for the facility inlet air system was activated to provide dry air for repeatable inlet conditions. New flow conditioning hardware was installed in the facility inlet plenum tank, which greatly reduced the inlet turbulence. The new inlet can also be easily modified to accommodate 20- or 22-in.-diameter fans and compressors, so a variety of existing hardware from other facilities (such as Glenn's 9- by 15-Foot Low-Speed Wind Tunnel) can be tested in the Single-Stage Axial Compressor Facility. An exhaust line was also installed to provide bleed capability to remove the inlet boundary layer. To improve the operation and control of the facility, a new programmable logic controller (PLC) was installed to upgrade from hardwired relay logic to software logic. The PLC also enabled the usage of human-machine interface software to allow for easier operation of the facility and easier reconfiguration of the facility controls when

  18. Noise evaluation of automotive A/C compressor

    Energy Technology Data Exchange (ETDEWEB)

    Metwally, Sameh M.; Khalil, Mohamed I.; Abouel-seoud, Shawki A. [Automotive and Tractors Dept., Faculty of Engineering, Helwan University, Cairo (Egypt)

    2011-07-01

    Passenger compartment's interior noise and thermal performance are essential criteria for the driving comfort of vehicles. The air-conditioning system influences both field of comfort. It creates comfortable thermal conditions. On the other hand, the noise radiation of the air-condition system's components can be annoying. The blower, the air distribution ducts and the registers affect air rush noise. In some cases, the refrigerant flow creates hissing noise. Such noise has a great influence on vehicle acoustical comfort and on overall quality perception of a vehicle Therefore, the acoustic performance of air-condition compressors become more important for passenger comfort. At engine idling and at extreme temperatures the air-condition compressor can be audible as the significant sound source. However, the aim of this paper is to quantify air-borne noise characteristics of vehicle air-condition compressor. A simulated experimental model comprises a small wooden box with dimensions of 0.5 x 0.5 x 0.5 m represented the principle of hemi-anechoic room was designed and acoustic characteristics of the sound field inside the box were determined. The air-condition compressor characteristics parameters considered in this paper are fan position and electric motor speed. In addition, a single number of the air column natural frequency is calculated. The results indicate that significant information can be obtained in order to investigate the vehicle air-condition compressor and consequently improve the vehicle interior quietness.

  19. CFD analysis of linear compressors considering load conditions

    Science.gov (United States)

    Bae, Sanghyun; Oh, Wonsik

    2017-08-01

    This paper is a study on computational fluid dynamics (CFD) analysis of linear compressor considering load conditions. In the conventional CFD analysis of the linear compressor, the load condition was not considered in the behaviour of the piston. In some papers, behaviour of piston is assumed as sinusoidal motion provided by user defined function (UDF). In the reciprocating type compressor, the stroke of the piston is restrained by the rod, while the stroke of the linear compressor is not restrained, and the stroke changes depending on the load condition. The greater the pressure difference between the discharge refrigerant and the suction refrigerant, the more the centre point of the stroke is pushed backward. And the behaviour of the piston is not a complete sine wave. For this reason, when the load condition changes in the CFD analysis of the linear compressor, it may happen that the ANSYS code is changed or unfortunately the modelling is changed. In addition, a separate analysis or calculation is required to find a stroke that meets the load condition, which may contain errors. In this study, the coupled mechanical equations and electrical equations are solved using the UDF, and the behaviour of the piston is solved considering the pressure difference across the piston. Using the above method, the stroke of the piston with respect to the motor specification of the analytical model can be calculated according to the input voltage, and the piston behaviour can be realized considering the thrust amount due to the pressure difference.

  20. A CFD study of Screw Compressor Motor Cooling Analysis

    Science.gov (United States)

    Branch, S.

    2017-08-01

    Screw compressors use electric motors to drive the male screw rotor. They are cooled by the suction refrigerant vapor that flows around the motor. The thermal conditions of the motor can dramatically influence the performance and reliability of the compressor. The more optimized this flow path is, the better the motor performance. For that reason it is important to understand the flow characteristics around the motor and the motor temperatures. Computational fluid dynamics (CFD) can be used to provide a detailed analysis of the refrigerant’s flow behavior and motor temperatures to identify the undesirable hot spots in the motor. CFD analysis can be used further to optimize the flow path and determine the reduction of hot spots and cooling effect. This study compares the CFD solutions of a motor cooling model to a motor installed with thermocouples measured in the lab. The compressor considered for this study is an R134a screw compressor. The CFD simulation of the motor consists of a detailed breakdown of the stator and rotor components. Orthotropic thermal conductivity material properties are used to represent the simplified motor geometry. In addition, the analysis includes the motor casings of the compressor to draw heat away from the motor by conduction. The study will look at different operating conditions and motor speeds. Finally, the CFD study will investigate the predicted motor temperature change by varying the vapor mass flow rates and motor speed. Recommendations for CFD modeling of such intricate heat transfer phenomenon have thus been proposed.

  1. Performance enhancement of hermetic compressor using phase change materials

    Science.gov (United States)

    Mahmoud, I. M.; Rady, M. A.; Huzayyin, A. S.

    2015-08-01

    The present study is motivated by the need for the research of simple measures for increasing energy efficiency of hermetic compressor. The measure is the application of phase change materials for performance enhancement. The first experimental study should be guide for choice of PCM. It has been performed to investigate the effects of thermostat setting temperature on the performance of hermetic compressor. The effects of thermostat setting temperature with and without load on power consumption have been analyzed. Performance enhancement using phase change materials (PCMs) has been studied by employing a phase change material Rubitherm-42 (RT-42) on the top surface of compressor. Choice of PCM material is based on basic compressor performance measured in the first part of the present study. Experiments have been carried out for different load values and different quantities of PCM. The quantity and phase change characteristic of PCM are essential parameters that determine the percentage of performance enhancement in term of energy consumption. Reduction of energy consumption of about 10% has been achieved in the present study by using PCM. The present study shows that how to reduce the electrical power consumption to enhance compressor heat dissipation method to improve efficiency.

  2. Analysis of steam-generator tube-rupture events combined with auxiliary-feedwater control-system failure for Three Mile Island-Unit 1 and Zion-Unit 1 pressurized water reactors

    International Nuclear Information System (INIS)

    Nassersharif, B.

    1986-01-01

    A steam-generator tube-rupture (SGTR) event combined with loss of all offsite alternating-current power and failure of the auxiliary-feedwater (AFW) control system has been investigated for the Three Mile Island-Unit 1 (TMI-1) and Zion-Unit 1 (Zion-1) pressurized water reactors. The Transient Reactor Analysis Code was used to simulate the accident sequence for each plant. The objectives of the study were to predict the plant transient response with respect to tube-rupture flow termination, extent of steam generator overfill, and thermal-hydraulic conditions in the steam lines. Two transient cases were calculated: (1) a TMI-1 SGTR and runaway-AFW transient, and (2) a Zion-1 SGTR and runaway-AFW transient. Operator actions terminated the tube-rupture flow by 1342 s (22.4 min) and 1440 s (24.0 min) for TMI-1 and Zion-1, respectively, but AFW injection was continued. The damaged steam generator (DSG) overfilled by 1273 s (21.2 min) for the TMI-1 calculation and by 1604 s (26.7 min) for the Zion-1 calculation. The DSG steam lines were completely filled by 1500 s (25 min) and 2000 s (33.3 min) for TMI-1 and Zion-1, respectively. The maximum subcooling in the steam lines was approx.63 K (approx.113 0 F) for TMI-1 and approx.44 K (approx.80 0 F) for Zion-1

  3. Probabilistic analysis of manufacturing uncertainties for an automotive turbocharger centrifugal compressor using numerical and experimental methods

    NARCIS (Netherlands)

    Javed, A.; Kamphues, E.; Hartuc, T.; Pecnik, R.; Van Buijtenen, J.P.

    2015-01-01

    The compressor impellers for mass-produced turbochargers are generally die-casted and machined to their final configuration. Manufacturing uncertainties are inherently introduced as stochastic dimensional deviations in the impeller geometry. These deviations eventually propagate into the compressor

  4. Experimental study of flow through compressor Cascade

    Directory of Open Access Journals (Sweden)

    Satyam Panchal

    2017-09-01

    Full Text Available The objective of this research work is to study the behaviour of flow at the inlet, within the blade passage and at the exit of a compressor cascade. For this purpose, a cascade with six numbers of aerofoil blades was designed and constructed. The cascade was fitted on the cascade test tunnel. Out of six blades two were instrumented for measuring the pressure distribution on the pressure and suction surface. The blades had a parabolic camber line, with a maximum camber position at 40% of the chord from the leading edge of the blade. The profile of the blade was C4, height of the blade was 160 mm, chord length was 80 mm, camber angle was 45° and stagger angle was 30°. Similarly, the length of the cascade was 300 mm, span was 160 mm, pitch was 60 mm, the actual chord of the cascade was 80 mm, the axial chord of the cascade was 70 mm, the stagger angle of the cascade was 30° and the pitch-chord ratio was 0.75. The data was taken and analyzed at −500% of the axial chord before the cascade, −25% of the axial chord before the leading edge, 25%, 50%, 75% and 150% of the axial chord from the leading edge of the blade. The readings were taken from the cascade wall to the mid span position along the pitch wise direction. The angle of incidence was also changed during the experiment and varied from i=−50°, −30°, −10° to 5°.

  5. Development and Testing of a Temperature-swing Adsorption Compressor for Carbon Dioxide in Closed-loop Air Revitalization Systems

    Science.gov (United States)

    Mulloth, Lila M.; Rosen, Micha; Affleck, David; LeVan, M. Douglas; Wang, Yuan

    2005-01-01

    The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby dosing the air-loop. We have developed a temperature-swing adsorption compressor (TSAC) that is energy efficient, quiet, and has no rapidly moving parts for performing these tasks. The TSAC is a solid-state compressor that has the capability to remove CO2 from a low- pressure source, and subsequently store, compress, and deliver at a higher pressure as required by a processor. The TSAC is an ideal interface device for CO2 removal and reduction units in the air revitalization loop of a spacecraft for oxygen recovery. This paper discusses the design and testing of a TSAC for carbon dioxide that has application in the ISS and future spacecraft for closing the air revitalization loop.

  6. Effects of casing treatment on a small, transonic axial-flow compressor

    Science.gov (United States)

    Holman, F. F.; Kidwell, J. R.

    1975-01-01

    Improved axial compressor surge margin through effective rotor casing treatment has been identified from test results on large axial compressors. A modified scale of a large compressor was built and tested to determine if similar improvements in surge margin could be duplicated in small-size turbomachinery. In addition, the effects of rotor radial running clearance, both with and without casing treatment, were investigated and are discussed. Test results of the scale configuration are presented and compared to the parent compressor.

  7. Characteristics and Outcomes of Pediatric Heart Failure-Related Emergency Department Visits in the United States: A Population-Based Study.

    Science.gov (United States)

    Mejia, Erika J; O'Connor, Matthew J; Lin, Kimberly Y; Song, Lihai; Griffis, Heather; Mascio, Christopher E; Shamszad, Pirouz; Donoghue, Aaron; Ravishankar, Chitra; Shaddy, Robert E; Rossano, Joseph W

    2018-02-01

    To describe the frequency, characteristics, and outcomes of heart failure-related emergency department (ED) visits in pediatric patients. We aimed to test the hypothesis that these visits are associated with higher admission rates, mortality, and resource utilization. A retrospective analysis of the Nationwide Emergency Department Sample for 2010 of patients ≤18 years of age was performed to describe ED visits with and without heart failure. Cases were identified using International Classification of Disease, Ninth Revision, Clinical Modification codes and assessed for factors associated with admission, mortality, and resource utilization. Among 28.6 million pediatric visits to the ED, there were 5971 (0.02%) heart failure-related cases. Heart failure-related ED patients were significantly more likely to be admitted (59.8% vs 4.01%; OR 35.3, 95% CI 31.5-39.7). Among heart failure-related visits, admission was more common in patients with congenital heart disease (OR 5.0, 95% CI 3.3-7.4) and in those with comorbidities including respiratory failure (OR 78.3, 95% CI 10.4-591) and renal failure (OR 7.9, 95% CI 1.7-36.3). Heart failure-related cases admitted to the hospital had a higher likelihood of death than nonheart failure-related cases (5.9% vs 0.32%, P failure (OR 4.5, 95% CI 2.2-9.2) and renal failure (OR 7.8, 95% CI 2.9-20.7). Heart failure-related ED visits were more expensive than nonheart failure-related ED visits ($1460 [IQR $861-2038] vs $778 [IQR $442-1375] [P failure-related visits represent a minority of pediatric ED visits but are associated with increased hospital admission and resource utilization. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Analysis of dose-incidence relationships for marrow failure in different species, in terms of radiosensitivity of tissue-rescuing units

    International Nuclear Information System (INIS)

    Hendry, J.H.; Roberts, S.A.

    1990-01-01

    The analysis of 68 published sets of dose-incidence data for marrow failure in different species, using a double-log mortality function, indicates: (a) There is more heterogeneity, i.e. greater sums-of-squares per degree of freedom, within the data sets for mouse than for larger species (monkey, dog, sheep, goat, pig). (b) For mice the curves for acute doses are characterized by a D0 of about 100 cGy for tissue-rescuing units (or target cells), which are depleted at most to about 3 x 10(-4) at LD50. (c) Larger species are much less tolerant to target-cell depletion, the corresponding level being consistently in the range of 10(-2)-10(-3) at LD50. Also, the D0 is often lower (approximately 55 cGy), which is compatible in the dog with such a value for hemopoietic progenitor cells. (d) With larger species there is an unexpected reduction in heterogeneity when the dose rate is lower, which gives a D0 lower than expected and a higher extrapolate. It is concluded that the position and slope of the dose-incidence curves are compatible with interpretations based primarily on target-cell number and survival characteristics, modified by additional heterogeneity factors

  9. Supercritical CO2 Compressor with Active Magnetic Bearing

    International Nuclear Information System (INIS)

    Cha, Jae Eun; Cho, Seong Kuk; Lee, JeKyoung; Lee, Jeong Ik

    2016-01-01

    For the stable operation of the sCO 2 integral test facility SCIEL, KAERI prepared Active Magnetic Bearing sCO 2 compressor for the 70,000RPM operation. Power generation test with AMB compressor will be finished within first half year of 2016 under supercritical state. The principal advantages of the sCO 2 Cycle are high efficiency at moderate temperature range, compact components size, simple cycle configuration, and compatibility with various heat sources. The Supercritical CO 2 Brayton Cycle Integral Experiment Loop (SCIEL) has been installed in Korea Atomic Energy Research Institute (KAERI) to develop the base technologies for the sCO 2 cycle power generation system. The operation of the SCIEL has mainly focused on sCO 2 compressor development and establishing sCO 2 system control logic

  10. Comparison of heat transfer models for reciprocating compressor

    International Nuclear Information System (INIS)

    Tuhovcak, J.; Hejcik, J.; Jicha, M.

    2016-01-01

    Highlights: • Comparison of integral heat transfer models. • Influence of heat transfer model on volumetric and isentropic efficiency. • Various gases used as working fluid. - Abstract: One of the main factors affecting the efficiency of reciprocating compressor is heat transfer inside the cylinder. An analysis of heat transfer could be done using numerical models or integral correlations developed mainly from approaches used in combustion engines; however their accuracy is not completely verified due to the complicated experimental set up. The goal of this paper is to analyse the effect of heat transfer on compressor efficiency. Various integral correlations were compared for different compressor settings and fluids. CoolProp library was used in the code to obtain the properties of common coolants and gases. A comparison was done using the in-house code developed in Matlab, based on 1st Law of Thermodynamics.

  11. Performance prediction of rotary compressor with hydrocarbon refrigerant mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Park, M.W.; Chung, Y.G. [Hanyang University Graduate School, Seoul (Korea); Park, K.W. [LG Industrial System Corporation Limited (Korea); Park, H.Y. [Hanyang University, Seoul (Korea)

    1999-04-01

    This paper presents the modeling approach that can be predicted transient behavior of rotary compressor. Mass and energy conservation laws are applied to the control volume, and real gas state equation is used to obtain thermodynamic properties of refrigerant. The valve equation is solved to analyze discharge process also. Dynamic analysis of vane and roller is carried out to gain friction work. From above modeling, the performance of rotary compressor with radial clearance and friction loss is investigated numerically. The performance of each refrigerant and the possibility of using the hydrocarbon refrigerant mixtures in an existing rotary compressor are estimated by applying R12, R134a, R290/R600a mixture also. (author). 6 refs., 13 figs., 1 tab.

  12. Mode change design for capacity modulation in reciprocating compressor

    International Nuclear Information System (INIS)

    Bae, Young Ju; Kim, Jin Kook; Kim, Jong Bong; Chang, Young June

    2008-01-01

    Due to environmental issues, the development of low energy consumption products has become one of the main topics in the home appliance industry. The energy consumption of a refrigerator depends on the efficiency of its compressor as well as on the refrigerator cycle design, such as the capacity modulation. This study features the design of a novel capacity modulation reciprocating compressor, i.e., two-step capacity modulation (TCM). In a TCM compressor, capacity modulation is achieved by changing the dead volume in the cylinder. Instead of a concentric sleeve, an eccentric sleeve is used to change the dead volume for the clockwise and counterclockwise rotation of a motor. For stable capacity modulation, a new latching system with a key, a spring, and an eccentric sleeve is introduced, and the mode change reliability is verified by dynamic analysis

  13. Supercritical CO{sub 2} Compressor with Active Magnetic Bearing

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jae Eun [KAERI, Daejeon (Korea, Republic of); Cho, Seong Kuk; Lee, JeKyoung; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    For the stable operation of the sCO{sub 2} integral test facility SCIEL, KAERI prepared Active Magnetic Bearing sCO{sub 2} compressor for the 70,000RPM operation. Power generation test with AMB compressor will be finished within first half year of 2016 under supercritical state. The principal advantages of the sCO{sub 2} Cycle are high efficiency at moderate temperature range, compact components size, simple cycle configuration, and compatibility with various heat sources. The Supercritical CO{sub 2} Brayton Cycle Integral Experiment Loop (SCIEL) has been installed in Korea Atomic Energy Research Institute (KAERI) to develop the base technologies for the sCO{sub 2} cycle power generation system. The operation of the SCIEL has mainly focused on sCO{sub 2} compressor development and establishing sCO{sub 2} system control logic.

  14. Effect of piping systems on surge in centrifugal compressors

    International Nuclear Information System (INIS)

    Tamaki, Hideaki

    2008-01-01

    There is a possibility that the exchange of the piping system may change the surge characteristic of a compressor. The piping system of a plant is not always the same as that of a test site. Then it is important to evaluate the effect of piping systems on surge characteristics in centrifugal compressors. Several turbochargers combined with different piping systems were tested. The lumped parameter model which was simplified to be solved easily was applied for the prediction of surge point. Surge lines were calculated with the linearlized lumped parameter model. The difference between the test and calculated results was within 10 %. Trajectory of surge cycle was also examined by solving the lumped parameter model. Mild surge and deep surge were successfully predicted. This study confirmed that the lumped parameter model was a very useful tool to predict the effect of piping systems on surge characteristics in centrifugal compressors, even though that was a simple model

  15. Internal flow measurement in transonic compressor by PIV technique

    Science.gov (United States)

    Wang, Tongqing; Wu, Huaiyu; Liu, Yin

    2001-11-01

    The paper presents some research works conducted in National Key Laboratory of Aircraft Engine of China on the shock containing supersonic flow measurement as well as the internal flow measurement of transoijc compressor by PIC technique. A kind of oil particles in diameter about 0.3 micrometers containing in the flow was discovered to be a very good seed for the PIV measurement of supersonic jet flow. The PIV measurement in over-expanded supersonic free jet and in the flow over wages show a very clear shock wave structure. In the PIV internal flow measurement of transonic compressor a kind of liquid particle of glycol was successful to be used as the seed. An illumination periscope with sheet forming optics was designed and manufactured, it leaded the laser shot generated from an integrate dual- cavity Nd:YAG laser of TSI PIV results of internal flow of an advanced low aspect ratio transonic compressor were shown and discussed briefly.

  16. Preventive maintenance basis: Volume 19 -- HVAC -- chillers and compressors. Final report

    International Nuclear Information System (INIS)

    Worledge, D.; Hinchcliffe, G.

    1997-12-01

    US nuclear power plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This document provides a program of preventive maintenance tasks suitable for application to HVAC -- Chillers and Compressors. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used in conjunction with material from other sources, to develop a complete PM program or to improve an existing program

  17. Development of a High Efficiency Compressor/Expander for an Air Cycle Air Conditioning System.

    Science.gov (United States)

    1982-11-15

    bearing, lb PHUB - Hub pressure (initial guess), psia RLG - Rotor length 1 ’B-2 RPM - Rotational speed, RPM R - Gas constant, lb -ft/lb - R CP - Specific...Compressor discharge port pressure ratio (PCD/PC2).:- CDP - Compressor pressure change, PCD-PCl PHUB - Pressure in compressor hub (acting on base of vanes

  18. More Options for the NLC Bunch Compressors (LCC-0035)

    International Nuclear Information System (INIS)

    Emma, P.

    2004-01-01

    The present bunch compressor design for the NLC allows control of the final bunch length by way of changes to the horizontal betatron phase advance of the 180 o -turnaround arc. This adjustability requirement significantly constrains the design and cost optimization of the system and excludes the possibility of using permanent magnet quadrupoles in the arc. To relieve this constraint, and to avoid the very strong arc focusing required at the upper limits of the bunch length range, we explore an option of bunch length control using the first compressor stage, with the arc optics fixed

  19. Chicane and wiggler based bunch compressors for future linear colliders

    International Nuclear Information System (INIS)

    Raubenheimer, T.O.; Emma, P.; Kheifets, S.

    1993-05-01

    In this paper, we discuss bunch compressors for future linear colliders. In the past, the bunch compression optics has been based upon achromatic cells using strong sextupoles to correct the dispersive and betatron chromaticity. To preserve the very small emittances required in most future collider designs, these schemes tend to have very tight alignment tolerances. Here, we describe bunch compressors based upon magnetic chicanes or wigglers which do need sextupoles to correct the chromatic emittance dilution. The dispersive chromaticity cancels naturally and the betatron chromaticity is not a significant source of emittance dilution. Thus, these schemes allow for substantially reduced alignment tolerances. Finally, we present a detailed design for the NLC linear collider

  20. Parametric optimization of the MVC desalination plant with thermomechanical compressor

    Science.gov (United States)

    Blagin, E. V.; Biryuk, V. V.; Anisimov, M. Y.; Shimanov, A. A.; Gorshkalev, A. A.

    2018-03-01

    This article deals with parametric optimization of the Mechanical Vapour Compression (MVC) desalination plant with thermomechanical compressor. In this plants thermocompressor is used instead of commonly used centrifugal compressor. Influence of two main parameters was studied. These parameters are: inlet pressure and number of stages. Analysis shows that it is possible to achieve better plant performance in comparison with traditional MVC plant. But is required reducing the number of stages and utilization of low or high initial pressure with power consumption maximum at approximately 20-30 kPa.

  1. Elements for modeling and design of centrifugal compressor housings

    International Nuclear Information System (INIS)

    Magoia, J.E.; Calderon, T.

    1990-01-01

    Various aspects of the structural analysis of centrifugal compressor housings are studied. These are usually used in different kinds of nuclear sites. Multiple areas of the analysis are evaluated with elastic models based on finite elements: sensitivity to different variables, quality of models on facing theoretical solutions and performed measurements. The development of an excentric bar element improved for the rigidized plate model, is included. The definition of criteria for a more efficient structural analysis as well as recommendations for the design of centrifugal compressor housings concludes the work. (Author) [es

  2. Associations between nursing home performance and hospital 30-day readmissions for acute myocardial infarction, heart failure and pneumonia at the healthcare community level in the United States.

    Science.gov (United States)

    Pandolfi, Michelle M; Wang, Yun; Spenard, Ann; Johnson, Florence; Bonner, Alice; Ho, Shih-Yieh; Elwell, Timothy; Bakullari, Anila; Galusha, Deron; Leifheit-Limson, Erica; Lichtman, Judith H; Krumholz, Harlan M

    2017-12-01

    To evaluate community-specific nursing home performance with community-specific hospital 30-day readmissions for Medicare patients discharged with acute myocardial infarction, heart failure or pneumonia. Cross-sectional study using 2009-2012 hospital risk-standardised 30-day readmission data for Medicare fee-for-service patients hospitalised for all three conditions and nursing home performance data from the Centers for Medicare & Medicaid Services Five-Star Quality Rating System. Medicare-certified nursing homes and acute care hospitals. 12,542 nursing homes and 3,039 hospitals treating 30 or more Medicare fee-for-service patients for all three conditions across 2,032 hospital service areas in the United States. Community-specific hospital 30-day risk-standardised readmission rates. Community-specific nursing home performance measures: health inspection, staffing, Registered Nurses and quality performance; and an aggregated performance score. Mixed-effects models evaluated associations between nursing home performance and hospital 30-day risk-standardised readmission rates for all three conditions. The relationship between community-specific hospital risk-standardised readmission rates and community-specific overall nursing home performance was statistically significant for all three conditions. Increasing nursing home performance by one star resulted in decreases of 0.29% point (95% CI: 0.12-0.47), 0.78% point (95% CI: 0.60-0.95) and 0.46% point (95% CI: 0.33-0.59) of risk-standardised readmission rates for AMI, HF and pneumonia, respectively. Among the specific measures, higher performance in nursing home overall staffing and Registered Nurse staffing measures was statistically significantly associated with lower hospital readmission rates for all three conditions. Notable geographic variation in the community-specific nursing home performance was observed. Community-specific nursing home performance is associated with community-specific hospital 30-day

  3. Development of an Experimental Data Base to Validate Compressor-Face Boundary Conditions Used in Unsteady Inlet Flow Computations

    Science.gov (United States)

    Sajben, Miklos; Freund, Donald D.

    1998-01-01

    The ability to predict the dynamics of integrated inlet/compressor systems is an important part of designing high-speed propulsion systems. The boundaries of the performance envelope are often defined by undesirable transient phenomena in the inlet (unstart, buzz, etc.) in response to disturbances originated either in the engine or in the atmosphere. Stability margins used to compensate for the inability to accurately predict such processes lead to weight and performance penalties, which translate into a reduction in vehicle range. The prediction of transients in an inlet/compressor system requires either the coupling of two complex, unsteady codes (one for the inlet and one for the engine) or else a reliable characterization of the inlet/compressor interface, by specifying a boundary condition. In the context of engineering development programs, only the second option is viable economically. Computations of unsteady inlet flows invariably rely on simple compressor-face boundary conditions (CFBC's). Currently, customary conditions include choked flow, constant static pressure, constant axial velocity, constant Mach number or constant mass flow per unit area. These conditions are straightforward extensions of practices that are valid for and work well with steady inlet flows. Unfortunately, it is not at all likely that any flow property would stay constant during a complex system transient. At the start of this effort, no experimental observation existed that could be used to formulate of verify any of the CFBC'S. This lack of hard information represented a risk for a development program that has been recognized to be unacceptably large. The goal of the present effort was to generate such data. Disturbances reaching the compressor face in flight may have complex spatial structures and temporal histories. Small amplitude disturbances may be decomposed into acoustic, vorticity and entropy contributions that are uncoupled if the undisturbed flow is uniform. This study

  4. Theoretical study of a novel refrigeration compressor - Part II: Performance of a rotating discharge valve in the revolving vane (RV) compressor

    Energy Technology Data Exchange (ETDEWEB)

    Teh, Y.L.; Ooi, K.T. [Thermal and Fluids Engineering Division, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, S639798 (Singapore); Djamari, D. Wibowo [Engineering Mechanics Division, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, S639798 (Singapore)

    2009-08-15

    A new refrigeration compressor, named 'Revolving Vane (RV) compressor', has been introduced in Part I of this paper series. For a first time in refrigeration compressors, a rotating discharge valve is employed in the RV compressor mainly due to the rotation of the entire cylinder. This paper presents a theoretical investigation on the dynamic behavior of a reed-type discharge valve undergoing rotatory motion, with the primary objective of elucidating the applicability of such valves in refrigeration compressors. Under the application of the Euler-Bernoulli beam theory, a mathematical model of the rotating valve is formulated and the transient response of the valve under centrifugal loads in addition to pressure forces is analyzed. Results have shown that under careful design considerations, the performance as well as the reliability of the rotating discharge valve can be enhanced as compared to a non-rotating valve that has been used in all refrigeration compressors currently. (author)

  5. Long-Duration Testing of a Temperature-Swing Adsorption Compressor for Carbon Dioxide for Closed-Loop Air Revitalization Systems

    Science.gov (United States)

    Rosen, Micha; Mulloth, Lila; Varghese, Mini

    2005-01-01

    This paper describes the results of long-duration testing of a temperature-swing adsorption compressor that has application in the International Space Station (ISS) and future spacecraft for closing the air revitalization loop. The air revitalization system of the ISS operates in an open loop mode and relies on the resupply of oxygen and other consumables from Earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. The TSAC is a solid-state compressor that has the capability to remove CO2 from a low-pressure source, and subsequently store, compress, and deliver at a higher pressure as required by a processor. The TSAC is an ideal interface device for CO2 removal and reduction units in the air revitalization loop of a spacecraft for oxygen recovery. The TSAC was developed and its operation was successfully verified in integration tests with the flight-like Carbon Dioxide Removal Assembly (CDRA) at Marshall Space Flight Center prior to the long-duration tests. Long-duration tests reveal the impacts of repeated thermal cycling on the compressor components and the adsorbent material.

  6. Ultrapure hydrogen thermal compressor based on metal hydrides for fuel cells and hybrid vehicles

    International Nuclear Information System (INIS)

    Almasan, V.; Biris, A.; Coldea, I.; Lupu, D.; Misan, I.; Popeneciu, G.; Ardelean, O.

    2007-01-01

    Full text: In hydrogen economy, efficient compressors are indispensable elements in the storage, transport and distribution of the produced hydrogen. Energetic efficient technologies can contribute to H 2 pipelines transport to the point of use and to distribute H 2 by refuelling stations. Characteristic for metal hydrides systems is the wide area of possibilities to absorb hydrogen at low pressure from any source of hydrogen, to store and deliver it hydrogen at high pressure (compression ratio more than 30). On the basis of innovative concepts and advanced materials for H 2 storage/compression (and fast thermal transfer), a fast mass (H 2 ) and heat transfer unit will be developed suitable to be integrated in a 3 stage thermal compressor. Metal hydrides used for a three stage hydrogen compression system must have different equilibrium pressures, namely: for stage 1, low pressure H 2 absorption and resistant to poisoning with impurities of hydrogen, for stage 2, medium pressure H 2 absorption and for stage 3, high pressure hydrogen delivery (120 bar). In the case of compression device based on metallic hydrides the most important properties are the hydrogen absorption/desorption rate, a smaller process enthalpy and a great structural stability on long term hydrogen absorption/desorption cycling. These properties require metal hydrides with large differences between the hydrogen absorption and desorption pressures at equilibrium, within a rather small temperature range. The main goal of this work is to search and develop metal hydride integrated systems for hydrogen purification, storage and compression. After a careful screening three hydrogen absorbing alloys will be selected. After selection, the work up of the alloys composition on the bases of detailed solid state studies, new multi-component alloys will be developed, with suitable thermodynamic and kinetic properties for a hydrogen compressor. The results of the study are the following: new types of hydrogen

  7. The design of a small linear-resonant, split Stirling cryogenic refrigerator compressor

    Science.gov (United States)

    Ackermann, R. A.

    1985-01-01

    The development of a small linear-resonant compressor for use in a 1/4-watt, 78K, split Stirling cryogenic refrigerator is discussed. The compressor contains the following special features: (1) a permanent-magnet linear motor; (2) resonant dynamics; (3) dynamic balancing; and (4) a close-clearance seal between the compressor piston and cylinder. This paper describes the design of the compressor, and presents component test data and system test data for the compressor driving a 1/4-watt expander.

  8. Respiratory Failure

    Science.gov (United States)

    Respiratory failure happens when not enough oxygen passes from your lungs into your blood. Your body's organs, ... brain, need oxygen-rich blood to work well. Respiratory failure also can happen if your lungs can' ...

  9. Experimental study of enhancing heating performance of the air-source heat pump by using a novel heat recovery device designed for reusing the energy of the compressor shell

    International Nuclear Information System (INIS)

    Huang, Bi; Jian, Qifei; Luo, Lizhong; Zhao, Jing

    2017-01-01

    Highlights: • A novel heat recovery device was designed and tested. • Aiming at avoiding liquid slugging in cold areas. • Recovery of the waste energy of compressor housing. • Refrigerant is heated with the energy recovered before it is sucked into the compressor. • Requires no extra power while the recovery system is operating. - Abstract: A novel heat recovery device designed to recover the heat that is released from the outer surface of heat pump compressors, and to enhance the performance of heat pumps in cold areas was made and tested in this study. The novel heat recovery device consists of three fundamental units: a heat absorption unit, a heat emission unit and heat pipes. An amount of work focused on recovering the heat of compressors through oil system, but few studies concentrated on the housing. The main advantage of the heat recovery device is no need for extra energy consumption for its only driving force is the temperature difference between the compressor shell and the working fluid inside the suction line. The experimental results were obtained from a series of tests with a R410A air-source heat pump. Effects of the device are analyzed with respect of the suction temperature, temperature distribution among the housing, input power and exergy destruction. Moreover, the impact on the heating capacity is also discussed. Further, direction for improvement is also given based on the analysis.

  10. Crack Propagation in Compressor Rotor Blade

    Science.gov (United States)

    2012-08-01

    Aerospace: Research and Development 86 Blenheim Crescent Ruislip, Middlesex HA4 7HB United Kingdom October 20, 2010 Distribution... Middlesex HA4 7HB United Kingdom April 20, 2011 Distribution A: Approved for public release; distribution is unlimited...September 2010, (Grant FA8655-10-1-3062), European Office of Aerospace: Research and Development, 86 Blenheim Crescent, Ruislip, Middlesex HA4 7HB

  11. Heart Failure

    Science.gov (United States)

    Heart failure is a condition in which the heart can't pump enough blood to meet the body's needs. Heart failure does not mean that your heart has stopped ... and shortness of breath Common causes of heart failure are coronary artery disease, high blood pressure and ...

  12. Development, field testing and implementation of automated hydraulically controlled, variable volume loading systems for reciprocating compressors

    Energy Technology Data Exchange (ETDEWEB)

    Hickman, Dwayne A. [ACI Services, Inc., Cambridge, OH (United States); Slupsky, John [Kvaerner Process Systems, Calgary, Alberta (Canada); Chrisman, Bruce M.; Hurley, Tom J. [Cooper Energy Services, Oklahoma City, OK (United States). Ajax Division

    2003-07-01

    Automated, variable volume unloaders provide the ability to smoothly load/unload reciprocating compressors to maintain ideal operations in ever-changing environments. Potential advantages provided by this load control system include: maximizing unit capacity, optimizing power economy, maintaining low exhaust emissions, and maintaining process suction and discharge pressures. Obstacles foreseen include: reliability, stability, serviceability and automation integration. Results desired include: increased productivity for the compressor and its operators, increased up time, and more stable process control. This presentation covers: system design features with descriptions of how different types of the devices were developed, initial test data, and how they can be effectively operated; three actual-case studies detailing the reasons why automated, hydraulically controlled, variable volume, head-end unloaders were chosen over other types of unloading devices; sophisticated software used in determining the device sizing and predicted performance; mechanical and field considerations; installation, serviceability and operating considerations; device control issues, including PC and PLC considerations; monitoring of actual performance and comparison of such with predicted performance; analysis of mechanical reliability and stability; and preliminary costs versus return on investment analysis. (author)

  13. Decimal multiplication using compressor based-BCD to binary converter

    Directory of Open Access Journals (Sweden)

    Sasidhar Mukkamala

    2018-02-01

    Full Text Available The objective of this work is to implement a scalable decimal to binary converter from 8 to 64 bits (i.e 2-digit to 16-digit using parallel architecture. The proposed converters, along with binary coded decimal (BCD adder and binary to BCD converters, are used in parallel implementation of Urdhva Triyakbhyam (UT-based 32-bit BCD multiplier. To increase the performance, compressor circuits were used in converters and multiplier. The designed hardware circuits were verified by behavioural and post layout simulations. The implementation was carried out using Virtex-6 Field Programmable Gate Array (FPGA and Application Specific Integrated Circuit (ASIC with 90-nm technology library platforms. The results on FPGA shows that compressor based converters and multipliers produced less amount of propagation delay with a slight increase of hardware resources. In case of ASIC implementation, a compressor based converter delay is equivalent to conventional converter with a slight increase of gate count. However, the reduction of delay is evident in case of compressor based multiplier.

  14. On the compressor ring for the JAERI neutron science project

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, Isao [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1997-11-01

    (1), As long as a 1.5 GeV-8 MW linear accelerator is constructed in the JAERI neutron science center, it is quite reasonable to construct a 5 MW compressor ring as a driver of a high intensity spallation neutron source to generate pulsed neutron beams. (2), Suppression of beam loss around the compressor ring to an acceptable level is the most crucial subject to be coped with in designing a MW-class compressor ring. This subject should be successfully cleared by carefully studying and designing the overall system of accelerator and tunnel. (3), The `PSR instability` was comprehensively discussed in the NSNS workshop held at Santa Fe in March, 1997, as a remaining problem of a high intensity proton compressor ring. People of Los Alamos attributed it to an e-p instability. But some questions like the cause that makes some part of protons leak away from a beam bunch to a bunch gap are yet left open. (4), A new scheme of two step H{sup 0} injection is proposed to remove defects of the conventional one of Los Alamos PSR. (author)

  15. Data compressor designed to improve recognition of magnetic phases

    Science.gov (United States)

    Vogel, E. E.; Saravia, G.; Cortez, L. V.

    2012-02-01

    Data compressors available in the web have been used to determine magnetic phases for two-dimensional (2D) systems [E. Vogel, G. Saravia, F. Bachmann, B. Fierro, J. Fischer, Phase transitions in Edwards-Anderson model by means of information theory, Physica A 388 2009 4075-4082]. In the present work, we push this line forward along four different directions. First, the compressor itself: we design a new data compressor, named wlzip, optimized for the recognition of information having physical (or scientific) information instead of the random digital information usually compressed. Second, for the first time we extend the data compression analysis to the 3D Ising ferromagnetic model using wlzip. Third, we discuss the tuning possibilities of wlzip in terms of the number of digits considered in the compression to yield maximum definition; in this way, the transition temperature of both 2D and 3D Ising ferromagnets can be reported with very good resolution. Fourth, the extension of the time window through which the data file is actually compressed is also considered to get optimum accuracy. The paper is focused on the new compressor, its algorithm in general and the way to apply it. Advantages and disadvantages of wlzip are discussed. Toward the end, we mention other possible applications of this technique to recognize stable and unstable regimes in the evolution of variables in meteorology (such as pollution content or atmospheric pressure), biology (blood pressure) and econophysics (prices of the stock market).

  16. Modulation method of scroll compressor based on suction gas bypass

    International Nuclear Information System (INIS)

    Wang Baolong; Han Linjun; Shi Wenxing; Li Xianting

    2012-01-01

    The air conditioners and heat pumps tend to work in much mild environments and part load situations rather than provide the rated full capacity under severe rated testing conditions. Both the capacity and inner compression ratio of the compressor should be regulated according to the working condition for higher energy efficiency and occupants’ comfort. A potential modulating technology of the scroll compressor, suction gas bypass, is investigated in this paper. The principle and operation method are illuminated and the adaptability is validated by experiments and simulations. As a conclusion, an appropriate suction gas bypass can reduce the inner compression loss of the scroll compressor under over compression conditions, enhance the system COP and also largely decrease the heating/cooling capacity of the refrigeration/heat pump system. - Highlights: ► Suction gas bypass (SGB) is an effective regulating method of scroll compressor. ► SGB reduces the inner compression loss under over compression conditions. ► SGB largely decreases the heating/cooling capacity of the refrigeration system.

  17. On the design of lubricant free piston compressors

    NARCIS (Netherlands)

    Owczarek, P.

    2010-01-01

    This thesis describes the development on long lifetime and an efficient piston compressor operating in a clean environment where oil lubrication must be excluded. Particularly in cooling systems including cryocoolers the presence of oil is a well known problem. A growing number of applications of

  18. Variable speed hermetic reciprocating compressors for domestic refrigerators

    DEFF Research Database (Denmark)

    Rasmussen, Bjarne D.

    1998-01-01

    This article describes the results of a both theoretical and experimental investigation of the performance of variable speed hermetic reciprocating compressors for domestic refrigerators. The investigation was performed as a part of a larger research project with the objective of reducing...

  19. Computational Method for Ice Crystal Trajectories in a Turbofan Compressor

    NARCIS (Netherlands)

    Grift, E.J.; Norde, Ellen; van der Weide, Edwin Theodorus Antonius; Hoeijmakers, Hendrik Willem Marie

    2015-01-01

    In this study the characteristics of ice crystals on their trajectory in a single stage of a turbofan engine compressor are determined. The particle trajectories are calculated with a Lagrangian method employing a classical fourth-order Runge-Kutta time integration scheme. The air flow field is

  20. Satellite refrigerator compressors with the oil and moisture removal systems

    International Nuclear Information System (INIS)

    Satti, J.A.

    1983-08-01

    There are twenty-eight compressors installed around the Main Accelerator Ring in seven locations. Drawing 9140-ME-129720 shows the piping and the components schematic for four Mycom compressor skids per building with each having an independent oil and moisture removal system. The Mycom skids each consist of an oil injected screw compressor of 750 SCFM capacity with a 350 hp motor, oil pump, oil cooler, and oil separator. Helium gas returning from the heat exchanger train is compressed from 1 atm to 20 atm in the compressor. The compressed gas is then passed through the three coalescer de-mister where oil mist is separated from the helium gas. The helium gas then flows through the charcoal adsorber and molecular sieve where any residual oil vapor and water vapor are removed. The final stage of purification is the final filter which removes any remaining particulates from the compressed helium gas. The end product of this system is compressed and purified helium gas ready to be cooled down to cryogenic temperatures

  1. Control and data acquisition system for rotary compressor

    Directory of Open Access Journals (Sweden)

    Buczaj Marcin

    2017-01-01

    Full Text Available The rotary compressor (crimping machine is a machine designed for making hollow forgings. The rotary compressor is a prototype device designed and built at the Technical University of Lublin. The compressor is dedicated to perform laboratory tests related to the hollow forgings of various shapes using different materials. Since the rotary compressor is an experimental device, there is no control and acquisition data system available. The article presents the concept and the capabilities of the computer control and data acquisition system supporting rotary compressing process. The main task of software system is acquisition of force and kinetic parameters related to the analysed process of the rotary forging compression. The software allows the user to declare the course of the forming forgings. This system allows current recording and analysis of four physical values: feed rate (speed of working head movement, hydraulic oil pressure at inlet and outlet of hydraulic cylinder and the torque of engine. Application functions can be divided into three groups: the configuration of the pressing process, the acquisition and analysis of data from the pressing process and the recording and presentation of stored results. The article contains a detailed description about hardware and software implementation of mentioned functions.

  2. Robust Stabilization of Jet Engine Compressor In The Presence of ...

    African Journals Online (AJOL)

    Compressors for jet engines in operation experience disturbances such as variations in the states of the system, mass flow, and pressure. These disturbances sometimes result in instabilities due to surge and stall, which adversely affect performance. In this work, first we modify the Moore and Grietzer three-state model for ...

  3. Gas compressor with side branch absorber for pulsation control

    Science.gov (United States)

    Harris, Ralph E [San Antonio, TX; Scrivner, Christine M [San Antonio, TX; Broerman, III, Eugene L.

    2011-05-24

    A method and system for reducing pulsation in lateral piping associated with a gas compressor system. A tunable side branch absorber (TSBA) is installed on the lateral piping. A pulsation sensor is placed in the lateral piping, to measure pulsation within the piping. The sensor output signals are delivered to a controller, which controls actuators that change the acoustic dimensions of the SBA.

  4. Reliability Approach of a Compressor System using Reliability Block ...

    African Journals Online (AJOL)

    pc

    2018-03-05

    Mar 5, 2018 ... This paper presents a reliability analysis of such a system using reliability ... Keywords-compressor system, reliability, reliability block diagram, RBD .... the same structure has been kept with the three subsystems: air flow, oil flow and .... and Safety in Engineering Design", Springer, 2009. [3] P. O'Connor ...

  5. Design and test of a high pressure centrifugal compressor

    International Nuclear Information System (INIS)

    Choi, Jae Ho; Han, Chak Heui; Paeng, Ki Seok; Chen, Seung Bae; Kim, Yong Ryun

    2005-01-01

    This paper presents an aerodynamic design, flow analysis and performance test of a pressure ratio 4:1 centrifugal compressor for gas turbine engine. The compressor is made up of a centrifugal impeller, a two-stage diffuser consisted of radial and axial types. The impeller has a 45 degree backswept angle and the design running tip clearance is 5% of impeller exit height. Three-dimensional numerical analysis is performed to analyze the flows in the impeller, diffuser and deswirler considering the impeller tip clearance. Test module and rig facilities for the compressor stage performance test are designed and fabricated. The overall compressor stage performances as well as the static pressure fields on the impeller and diffuser are measured. Two diffusers of wedge and airfoil types are tested with an impeller. The calculation and test results show that flow fields downstream the deswirler at the design and off-design points are highly nonuniform and the airfoil diffuser has the better aerodynamic characteristics than those of wedge diffuser

  6. Surge control of the electrically driven centrifugal compressor

    NARCIS (Netherlands)

    Boinov, K.O.; Lomonova, E.A.; Vandenput, A.J.A.; Tyagounov, A.

    2006-01-01

    This paper presents a method of the energy efficiency and the operational performance improvement of the electrically driven air compression system. The key innovation of the proposed method-the active surge suppression of the centrifugal compressor by means of the speed control of the electrical

  7. Machine characteristics, system arrangement, driver and operation effects on surge of dynamic compressor in oil and gas plants

    Energy Technology Data Exchange (ETDEWEB)

    Almasi, Amin

    2012-12-15

    Working in the surge area will result in an unstable compressor operation, exposing the dynamic compressor (centrifugal compressor or axial compressor) to destructive stress, high vibration and other damaging effects. The destructive power of the surge is enormous, ranging from changes in clearances, which result in a penalty in the compressor efficiency, to destruction of parts leading to bearing, rotor or seal replacements. The effects of compressor characteristics, driver type, compressor accessories, vent valve, check valve, trip delay and operation details on surge events and anti-surge system designs are studied. A case study is also discussed. (orig.)

  8. Oil flow at the scroll compressor discharge: visualization and CFD simulation

    Science.gov (United States)

    Xu, Jiu; Hrnjak, Pega

    2017-08-01

    Oil is important to the compressor but has other side effect on the refrigeration system performance. Discharge valves located in the compressor plenum are the gateway for the oil when leaving the compressor and circulate in the system. The space in between: the compressor discharge plenum has the potential to separate the oil mist and reduce the oil circulation ratio (OCR) in the system. In order to provide information for building incorporated separation feature for the oil flow near the compressor discharge, video processing method is used to quantify the oil droplets movement and distribution. Also, CFD discrete phase model gives the numerical approach to study the oil flow inside compressor plenum. Oil droplet size distributions are given by visualization and simulation and the results show a good agreement. The mass balance and spatial distribution are also discussed and compared with experimental results. The verification shows that discrete phase model has the potential to simulate the oil droplet flow inside the compressor.

  9. Modeling and investigation of refrigeration system performance with two-phase fluid injection in a scroll compressor

    Science.gov (United States)

    Gu, Rui

    Vapor compression cycles are widely used in heating, refrigerating and air-conditioning. A slight performance improvement in the components of a vapor compression cycle, such as the compressor, can play a significant role in saving energy use. However, the complexity and cost of these improvements can block their application in the market. Modifying the conventional cycle configuration can offer a less complex and less costly alternative approach. Economizing is a common modification for improving the performance of the refrigeration cycle, resulting in decreasing the work required to compress the gas per unit mass. Traditionally, economizing requires multi-stage compressors, the cost of which has restrained the scope for practical implementation. Compressors with injection ports, which can be used to inject economized refrigerant during the compression process, introduce new possibilities for economization with less cost. This work focuses on computationally investigating a refrigeration system performance with two-phase fluid injection, developing a better understanding of the impact of injected refrigerant quality on refrigeration system performance as well as evaluating the potential COP improvement that injection provides based on refrigeration system performance provided by Copeland.

  10. Compressor Calorimeter Test of R-410A Alternative: R-32/134a Mixture Using a Scroll Compressor

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, Som S [ORNL; Sharma, Vishaldeep [ORNL; Abdelaziz, Omar [ORNL

    2014-02-01

    As a contribution to the AHRI Low-GWP Alternative Refrigerants Evaluation Program (AREP), this study compares the performance of lower-GWP alternative refrigerant R-32 + R-134a mixture, to that of refrigerant R-410A (baseline) in a scroll compressor designed for air-conditioning and heat pump applications. These comparisons were carried out via compressor calorimeter tests performed on a compressor designed for refrigerant R-410A and having a nominal rated capacity of 21,300 Btu/hr. Tests were conducted over a suction dew point temperature range of 10 F to 55 F in 5 F increments and a discharge dew point temperature range of 70 F to 140 F in 10 F increments. All the tests were performed with 20 F superheat, 40 F superheat, and 65 F suction temperature. A liquid subcooling level of 15 F was maintained for all the test conditions. The tests showed that the discharge temperature of the alternative refrigerant was higher than that of R-410A at all test conditions. Also, the energy efficiency ratio (EER) and cooling capacity of compressor using the alternative refrigerant were slightly lower in comparison to that of R-410A.

  11. Experimental Investigation of Inlet Distortion in a Multistage Axial Compressor

    Science.gov (United States)

    Rusu, Razvan

    The primary objective of this research is to present results and methodologies used to study total pressure inlet distortion in a multi-stage axial compressor environment. The study was performed at the Purdue 3-Stage Axial Compressor Facility (P3S) which models the final three stages of a production turbofan engine's high-pressure compressor (HPC). The goal of this study was twofold; first, to design, implement, and validate a circumferentially traversable total pressure inlet distortion generation system, and second, to demonstrate data acquisition methods to characterize the inter-stage total pressure flow fields to study the propagation and attenuation of a one-per-rev total pressure distortion. The datasets acquired for this study are intended to support the development and validation of novel computational tools and flow physics models for turbomachinery flow analysis. Total pressure inlet distortion was generated using a series of low-porosity wire gauze screens placed upstream of the compressor in the inlet duct. The screens are mounted to a rotatable duct section that can be precisely controlled. The P3S compressor features fixed instrumentation stations located at the aerodynamic interface plane (AIP) and downstream and upstream of each vane row. Furthermore, the compressor features individually indexable stator vanes which can be traverse by up to two vane passages. Using a series of coordinated distortion and vane traverses, the total pressure flow field at the AIP and subsequent inter-stage stations was characterized with a high circumferential resolution. The uniformity of the honeycomb carrier was demonstrated by characterizing the flow field at the AIP while no distortion screens where installed. Next, the distortion screen used for this study was selected following three iterations of porosity reduction. The selected screen consisted of a series of layered screens with a 100% radial extent and a 120° circumferential extent. A detailed total

  12. A study on flow development in an APU-style inlet and its effect on centrifugal compressor performance

    Science.gov (United States)

    Lou, Fangyuan

    The objectives of this research were to investigate the flow development inside an APU-style inlet and its effect on centrifugal compressor performance. The motivation arises from the increased applications of gas turbine engines installed with APU-style inlets such as unmanned aerial vehicles, auxiliary power units, and helicopters. The inlet swirl distortion created from these complicated inlet systems has become a major performance and operability concern. To improve the integration between the APU-style inlet and gas turbine engines, better understanding of the flow field in the APU-style inlet and its effect on gas turbine is necessary. A research facility for the purpose of performing an experimental investigation of the flow field inside an APU-style inlet was developed. A subcritical air ejector is used to continuously flow the inlet at desired corrected mass flow rates. The facility is capable of flowing the APU inlet over a wide range of corrected mass flow rate that matches the same Mach numbers as engine operating conditions. Additionally, improvement in the system operational steadiness was achieved by tuning the pressure controller using a PID control method and utilizing multi-layer screens downstream of the APU inlet. Less than 1% relative unsteadiness was achieved for full range operation. The flow field inside the rectangular-sectioned 90? bend of the APU-style inlet was measured using a 3-Component LDV system. The structures for both primary flow and the secondary flow inside the bend were resolved. Additionally, the effect of upstream geometry on the flow development in the downstream bend was also investigated. Furthermore, a Single Stage Centrifugal Compressor research facility was developed at Purdue University in collaboration with Honeywell to operate the APU-style inlet at engine conditions with a compressor. To operate the facility, extensive infrastructure for facility health monitoring and performance control (including lubrication

  13. Contraceptive failure

    DEFF Research Database (Denmark)

    Rasch, Vibeke

    2002-01-01

    Most studies focusing on contraceptive failure in relation to pregnancy have focused on contraceptive failure among women having induced abortions, thereby neglecting those women who, despite contraceptive failure, accept the pregnancy and intend to carry the fetus to term. To get a more complete...... picture of the problem of contraceptive failure, this study focuses on contraceptive failure among women with diverse pregnancy outcomes. In all, 3520 pregnant women attending Odense University Hospital were included: 373 had induced abortions, 435 had spontaneous abortions, 97 had ectopic pregnancies......, and 2614 received antenatal care. The variables studied comprise age, partner relationship, number of births, occupational and economical situation, and contraceptive use.Contraceptive failure, defined as contraceptive use (condom, diaphragm, IUD, oral contraception, or another modern method...

  14. Heart Failure

    OpenAIRE

    McMurray, John; Ponikowski, Piotr

    2011-01-01

    Heart failure occurs in 3% to 4% of adults aged over 65 years, usually as a consequence of coronary artery disease or hypertension, and causes breathlessness, effort intolerance, fluid retention, and increased mortality. The 5-year mortality in people with systolic heart failure ranges from 25% to 75%, often owing to sudden death following ventricular arrhythmia. Risks of cardiovascular events are increased in people with left ventricular systolic dysfunction (LVSD) or heart failure.

  15. Air compressor multi-pattern smart monitor

    Science.gov (United States)

    Zhao, Qiancheng; Qin, Yejun; Dai, Juchuan; Huang, Geng

    2011-12-01

    The device is controlled by TMS320F2812 microprocessor. It mainly includes signal acquisition circuit, keyboard circuit, Chinese / English LCD display circuit, the calendar clock circuits, alarm circuits, relay output circuit, communications interface circuits, DI / DO circuit, power circuit and CPU circuit and so on. In addition, the device integrates a sensor transmission circuit, so it can directly connect with temperature pressure sensors to achieve high-precision measurement and monitoring. According to needs of users, it can work in different modes without the additional controller respectively. The equipment can communicate with each other by CAN bus or RS485. It mainly can realize the control and analysis of equipment status, failure predication and diagnosis, information management, etc.

  16. The mechanical design of a vapor compressor for a heat pump to be used in space

    Science.gov (United States)

    Berner, F.; Oesch, H.; Goetz, K.; Savage, C. J.

    1982-01-01

    A heat pump developed for use in Spacelab as a stand-alone refrigeration unit as well as within a fluid loop system is discussed. It will provide an active thermal control for payloads. Specifications for the heat pump were established: (1) heat removal rates at the source; (2) heat source temperatures from room temperature; (3) heat-sink fluid temperatures at condenser inlet; and (4) minimum power consumption. A reversed Carnot cycle heat pump using Freon 12 as working fluid incorporating a one-cylinder reciprocating compressor was selected. The maximum crankshaft speed was fixed relatively high at 100 rpm. The specified cooling rates then made it necessary to select a cylinder volume of 10 cu cm, which was obtained with a bore of 40 mm and a stroke of 8 mm.

  17. Aerodynamic optimization of supersonic compressor cascade using differential evolution on GPU

    Energy Technology Data Exchange (ETDEWEB)

    Aissa, Mohamed Hasanine; Verstraete, Tom [Von Karman Institute for Fluid Dynamics (VKI) 1640 Sint-Genesius-Rode (Belgium); Vuik, Cornelis [Delft University of Technology 2628 CD Delft (Netherlands)

    2016-06-08

    Differential Evolution (DE) is a powerful stochastic optimization method. Compared to gradient-based algorithms, DE is able to avoid local minima but requires at the same time more function evaluations. In turbomachinery applications, function evaluations are performed with time-consuming CFD simulation, which results in a long, non affordable, design cycle. Modern High Performance Computing systems, especially Graphic Processing Units (GPUs), are able to alleviate this inconvenience by accelerating the design evaluation itself. In this work we present a validated CFD Solver running on GPUs, able to accelerate the design evaluation and thus the entire design process. An achieved speedup of 20x to 30x enabled the DE algorithm to run on a high-end computer instead of a costly large cluster. The GPU-enhanced DE was used to optimize the aerodynamics of a supersonic compressor cascade, achieving an aerodynamic loss minimization of 20%.

  18. Comparative assessment of characteristic part-load performances of screw compressors and turbo-compressors; Vergleich der charakteristischen Teillastwirkungsgrade von Schrauben- und Turboverdichtern

    Energy Technology Data Exchange (ETDEWEB)

    Brasz, J.J.; Hartmann, K. [Carrier Corp., Syracuse, NY (United States)]|[Carrier Corp., Muenchen (Germany)

    2006-07-01

    The relative part-load performance of screw compressors and radial compressors is compared. Compressor part load is represented by a 2D characteristic field with the pressure on the vertical axis as a function of mass flow on the horizontal axis, with efficiencies given for any possible combination of pressure and mass flow. While this manner of representation is common for radial compressors, it is new for screw compressors. In the comparison of compression efficiencies, the focus is on vapour compression. For a valid comparative assessment of total compression, also the mechanical and/or electric loss through bearings, transmission, drive and (in case of variable-speed drives) frequency converters must be taken into account. (orig.)

  19. Active magnetic bearing for use in compressors and other turbomachinery

    International Nuclear Information System (INIS)

    Hennau, J.N.

    1989-01-01

    Active magnetic bearings and dry gas seals are now in operation on quite a number of compressors, turbines and generators, proving than an oil-free system is actually working and that furthermore, it has merits in energy savings, rotor dynamic monitoring and improved reliability. The technology of active magnetic bearing has been developed mainly in France after the Second World War for space application, but soon there appeared the large possibilities in industrial applications starting with the vacuum industry (turbomolecular pump), followed by the machine tool industry (high power and high speed milling and grinding spindles) and the large turbomachinery field (centrifugal compressors, blowers, steam and gas turbines, turbogenerators). Merits of the active magnetic bearing vary from one application to another, but they all derive from the fact that we have no contact between the rotor and the stator and that the electronic control of the bearings can cope with the rotor dynamics and provide useful information on the operating conditions

  20. Active surge control for variable speed axial compressors.

    Science.gov (United States)

    Lin, Shu; Yang, Chunjie; Wu, Ping; Song, Zhihuan

    2014-09-01

    This paper discusses active surge control in variable speed axial compressors. A compression system equipped with a variable area throttle is investigated. Based on a given compressor model, a fuzzy logic controller is designed for surge control and a proportional speed controller is used for speed control. The fuzzy controller uses measurements of the change of pressure rise as well as the change of mass flow to determine the throttle opening. The presented approach does not require the knowledge of system equilibrium or the surge line. Numerical simulations show promising results. The proposed fuzzy logic controller performs better than a backstepping controller and is capable to suppress surge at different operating points. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  1. Compressor noise control begins with design--Part 2

    International Nuclear Information System (INIS)

    Frank, L.

    1993-01-01

    Reduction of noise pollution at gas compressor stations associated with natural gas pipelines and distribution systems, has long been a complex problem. Specified noise levels of individual components tell nothing of the overall system when it is installed and placed in a site-specific setting. Further, testing for compliance performance guarantees is virtually impossible to conduct at a distant location because one cannot distinguish among various contributing noise sources. This paper develops a plan for calculating an estimate of sound generation from a compressor station and the methods for controlling and measuring sounds of individual components. It also classifies the types of noise and gives various methods of dealing with each noise type

  2. Simplified Model and Response Analysis for Crankshaft of Air Compressor

    Science.gov (United States)

    Chao-bo, Li; Jing-jun, Lou; Zhen-hai, Zhang

    2017-11-01

    The original model of crankshaft is simplified to the appropriateness to balance the calculation precision and calculation speed, and then the finite element method is used to analyse the vibration response of the structure. In order to study the simplification and stress concentration for crankshaft of air compressor, this paper compares calculative mode frequency and experimental mode frequency of the air compressor crankshaft before and after the simplification, the vibration response of reference point constraint conditions is calculated by using the simplified model, and the stress distribution of the original model is calculated. The results show that the error between calculative mode frequency and experimental mode frequency is controlled in less than 7%, the constraint will change the model density of the system, the position between the crank arm and the shaft appeared stress concentration, so the part of the crankshaft should be treated in the process of manufacture.

  3. Numerical Simulation and Performance Analysis of Twin Screw Air Compressors

    Directory of Open Access Journals (Sweden)

    W. S. Lee

    2001-01-01

    Full Text Available A theoretical model is proposed in this paper in order to study the performance of oil-less and oil-injected twin screw air compressors. Based on this model, a computer simulation program is developed and the effects of different design parameters including rotor profile, geometric clearance, oil-injected angle, oil temperature, oil flow rate, built-in volume ratio and other operation conditions on the performance of twin screw air compressors are investigated. The simulation program gives us output variables such as specific power, compression ratio, compression efficiency, volumetric efficiency, and discharge temperature. Some of the above results are then compared with experimentally measured data and good agreement is found between the simulation results and the measured data.

  4. Improvement in oil seal performance of gas compressor in HTTR

    International Nuclear Information System (INIS)

    Oyama, Sunao; Hamamoto, Shimpei; Nemoto, Takahiro; Sekita, Kenji; Isozaki, Minoru; Emori, Kouichi; Ohta, Yukimaru; Mizushima, Toshihiko; Kaneshiro, Noriyuki; Ito, Yoshiteru; Yamamoto, Hideo

    2007-08-01

    High-Temperature engineering Test Reactor (HTTR) built by Japan Atomic Energy Agency (JAEA) has reciprocating compressor commonly used to extract and discharge helium gas into primary/secondary coolant helium loop from helium purification system. Piston rod seal of the compressor consist of several components to prevent coolant leak. However, rod seal system has weak reliability during long term operation due to repeated leakage of seal oil in operation. As a result of investigations, leakage's root is found in that seal were used in a range beyond limit sliding properties of seal material. For this reason, a lip of the seal was worn and transformed itself and was not able to sustain a seal function. Therefore, through tests using facility actual equipment for endurance of candidate materials, one seal material were chosen for long term operation. (author)

  5. Basic Study on Engine with Scroll Compressor and Expander

    Science.gov (United States)

    Morishita, Etsuo; Kitora, Yoshihisa; Nishida, Mitsuhiro

    Scroll compressors are becoming popular in air conditioning and refrigeration. This is primarily due to their higher efficiency and low noise/vibration characteristics. The scroll principle can be applied also to the steam expander and the Brayton cycle engine,as shown in the past literature. The Otto cycle spark-ignition engine with a scroll compressor and expander is studied in this report. The principle and basic structure of the scroll engine are explained,and the engine characteristic are calculated based on the idealized cycles and processes. A prototype model has been proposed and constructed. The rotary type engine has always had a problem with sealing. The scroll engine might overcome this shortcoming with its much lower rubbing speed compared to its previous counterparts,and is therefore worth investigating.

  6. Reverse-Tangent Injection in a Centrifugal Compressor

    Science.gov (United States)

    Skoch, Gary J.

    2007-01-01

    Injection of working fluid into a centrifugal compressor in the reverse tangent direction has been invented as a way of preventing flow instabilities (stall and surge) or restoring stability when stall or surge has already commenced. The invention applies, in particular, to a centrifugal compressor, the diffuser of which contains vanes that divide the flow into channels oriented partly radially and partly tangentially. In reverse-tangent injection, a stream or jet of the working fluid (the fluid that is compressed) is injected into the vaneless annular region between the blades of the impeller and the vanes of the diffuser. As used here, "reverse" signifies that the injected flow opposes (and thereby reduces) the tangential component of the velocity of the impeller discharge. At the same time, the injected jet acts to increase the radial component of the velocity of the impeller discharge.

  7. Noise Reduction Design of the Volute for a Centrifugal Compressor

    Science.gov (United States)

    Song, Zhen; Wen, Huabing; Hong, Liangxing; Jin, Yudong

    2017-08-01

    In order to effectively control the aerodynamic noise of a compressor, this paper takes into consideration a marine exhaust turbocharger compressor as a research object. According to the different design concept of volute section, tongue and exit cone, six different volute models were established. The finite volume method is used to calculate the flow field, whiles the finite element method is used for the acoustic calculation. Comparison and analysis of different structure designs from three aspects: noise level, isentropic efficiency and Static pressure recovery coefficient. The results showed that under the concept of volute section model 1 yielded the best result, under the concept of tongue analysis model 3 yielded the best result and finally under exit cone analysis model 6 yielded the best results.

  8. Numerical Calculation of the Flow in a Centrifugal Compressor Volute

    International Nuclear Information System (INIS)

    Seong, Seon Mo; Kang, Shin Hyoung; Cho, Kyung Seok; Kim, Woo June

    2007-01-01

    Flows in the centrifugal compressor volute with circular cross section are numerically investigated. The computational domain contained inlet passage, impeller, radial and axial diffuser, and volute. The volute grid for the calculation utilized a multi-block arrangement to form a butterfly grid and flow calculations are performed using commercial CFD software, CFX-TASCflow. The centrifugal compressor of this study has the inlet passage like steps and axial diffuser after radial diffuser because of the shape of the motor cooling fins and installation constraints. Due to this feature the swirling flow pattern is different from the other investigations. The loss in through the inlet passage was considerable and the flow inside volute is very complex and three dimensional with strong vortex and recirculation through volute tongue

  9. Performance Improvement of a Centrifugal Compressor by Passive Means

    Directory of Open Access Journals (Sweden)

    N. Sitaram

    2012-01-01

    Full Text Available The present experimental investigation deals with performance improvement of a low-speed centrifugal compressor by inexpensive passive means such as turbulence generator placed at different positions and partial shroud near the rotor blade tip. The experiments are carried out at three values of tip clearance, namely 2.2%, 5.1%, and 7.9% of rotor blade height at the exit. Performance tests are carried out for a total of 13 configurations. From these measurements, partial shroud is found to give the best performance. The improvement in the compressor performance may be due to the reduction of tip leakage flows by the small extension of partial shroud (2 mm on the pressure surface side. Although there is nominal change in performance due to turbulence generator (TG, TG has beneficial effect of increased operating range.

  10. A High Reliability Gas-driven Helium Cryogenic Centrifugal Compressor

    CERN Document Server

    Bonneton, M; Gistau-Baguer, Guy M; Turcat, F; Viennot, P

    1998-01-01

    A helium cryogenic compressor was developed and tested in real conditions in 1996. The achieved objective was to compress 0.018 kg/s Helium at 4 K @ 1000 Pa (10 mbar) up to 3000 Pa (30 mbar). This project was an opportunity to develop and test an interesting new concept in view of future needs. The main features of this new specific technology are described. Particular attention is paid to the gas bearing supported rotor and to the pneumatic driver. Trade off between existing technologies and the present work are presented with special stress on the bearing system and the driver. The advantages are discussed, essentially focused on life time and high reliability without maintenance as well as non pollution characteristic. Practical operational modes are also described together with the experimental performances of the compressor. The article concludes with a brief outlook of future work.

  11. Linear Gain for the Microbunching Instability in an RF Compressor

    International Nuclear Information System (INIS)

    Venturini, M.; Migliorati, M.; Ronsivalle, C.; Vaccarezza, C.

    2009-01-01

    Velocity (or rf) compression has been suggested as a technique for bunch compression complementary to the more established technique involving magnetic chicanes and represents an important research item being investigated at the SPARC test facility. One of the aspects of this technique still not sufficiently understood is its possible impact on the microbunching instability. The purpose of this report is to present the analytical framework for investigating this instability in rf compressors. We use methods similar to those successfully applied to magnetic compressors and derive some integral equations yielding the gain for the instability in linear approximation. The focus here is on the derivation of the relevant equations. Although examples of solutions to these equations are provided we defer a more comprehensive discussion of their implication to a future report. The present study is part of a larger effort for a more comprehensive investigation that eventually will include macroparticle simulations and experiments.

  12. Device for covering a string of pump-compressor pipes

    Energy Technology Data Exchange (ETDEWEB)

    Sharafutdinov, I.G.; Prokopov, O.I.; Rastorgyev, M.A.

    1982-01-01

    The invention refers to oil field equipment, and more specifically to devices for automatic coverage of the flow of gusher oil and gas wells during the development of a fire near the well. A device is described for covering the string of pump-compressor pipes which includes a housing with piston connected to the string of pump-compressor pipes, shoe, seat and assembly for fixing the piston in the upper position with heat-sensitive substance. It is distinguished by the fact that in order to improve reliability of its triggering when a fire develops, the assembly for fixing the piston is equipped with hydraulic cylinders whose rods are connected to the piston, and the heat sensitive substance is placed in the vessels whose cavities are connected to the above-piston cavities of the hydraulic cylinders and are connected by a common collector.

  13. Multi-bunch energy compensation in the NLC bunch compressor

    International Nuclear Information System (INIS)

    Zimmermann, F.; Raubenheimer, T.O.; Thomson, K.A.

    1996-06-01

    The task of the NLC bunch compressor is to reduce the length of each bunch in a train of 90 bunches from 4 mm, at extraction from the damping ring, to about 100 μm, suitable for injection into the X-band main linac. This task is complicated by longitudinal long-range wake fields and the multi-bunch beam loading in the various accelerating sections of the compressor. One possible approach to compensate the multi-bunch beam loading is to add two RF systems with slightly different frequencies (' Δf' scheme) to each accelerating section, as first proposed by Kikuchi. This paper summarizes the choice of parameters for three such compensating sections, and presents simulation results of combined single- and multi-bunch dynamics for four different NLC versions. The multi-bunch energy compensation is shown to be straightforward and its performance to be satisfactory

  14. Dedicated monitoring and machinery protection systems on reciprocating compressors

    Energy Technology Data Exchange (ETDEWEB)

    Grande, Alvaro; Wenisch, Markus [Hoerbiger Ventilwerke GmbH and Co KG, Wien (Austria); Jacobs, Denis [HOERBIGER do Brasil Industria de Equipamentos, Cajamar, SP (Brazil)

    2012-07-01

    Growing demands on reciprocating compressors (recips) in the process gas industry require particular solutions for machinery protection and performance monitoring systems. Compared to rotating equipment, monitoring systems for recips have to consider the special mechanical and physical characteristics, such as oscillating masses, variable vibration behaviour and varying operating conditions. Furthermore, they provide valuable information about the performance of cylinder related components allowing the operator the optimization of efficiency and availability, and therefore increase production. (author)

  15. Aero-Mechanical Coupling in a High-Speed Compressor

    Science.gov (United States)

    2010-02-01

    freedom mass-spring- damper system as χ = ς 2 √ κµ . (51) ς represents the viscous damping, κ is the system stiffness and µ the system mass. χ expresses...between the fluid and structures which are common in modern, high-speed axial compressors. There were two major areas of focus. The first was the...development of measurement technique specifically for the study of these phenomena, termed Blade Image Velocimetry (BIV). The technique can measure fluid and

  16. Modernization of the Transonic Axial Compressor Test Rig

    Science.gov (United States)

    2017-12-01

    Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202- 4302, and to the Office of Management and Budget, Paperwork... maintenance requirements in the system by replacing the turbine drive with an electric drive train. The replacement of the turbine is the first phase in...stage compressor that consumes 1 MW of electric power. This work seeks improved efficiency and decreased maintenance requirements in the system by

  17. CFD Modelling in Screw Compressors With Complex Multi Rotor Configurations

    OpenAIRE

    Rane, Sham Ramchandra; Kovacevic, Ahmed; Kethidi, Madhulika

    2012-01-01

    Computational Fluid Dynamics (CFD) of screw compressors is challenging due to the positive displacement nature of the process, existence of very fine fluid leakage paths, coexistence of working fluid and lubricant or coolant, fluid injection and most importantly the lack of methodologies available to generate meshes required for the full three dimensional transient simulations. In this paper, currently available technology of grid remeshing has been used to demonstrate the CFD simulations of ...

  18. Flow and pressure characteristics within a screw compressor

    Science.gov (United States)

    Guerrato, D.; Nouri, J. M.; Stosic, N.; Arcoumanis, C.

    2007-10-01

    The angle-resolved mean and turbulence characteristics of the axial air flow inside a screw compressor with both male and female rotors have been measured, using a laser Doppler velocimeter (LDV) with high spatial and temporal resolution at different radial and axial locations for speeds of 800-1600 rpm, discharge pressures of 1-1.6 bar and discharge temperatures of 33-90°C. The velocity measurements were performed through a special transparent window fixed near the discharge port. The results confirmed the ability of the LDV technique to characterise the flow inside the compressor working chamber; an angular resolution of 1.5° was able to fully describe the velocity field within the machine. The flow variation between the different working chambers was established as well as the spatial variation of the axial mean velocity and turbulence velocity fluctuation within the working chamber. The effect of discharge port opening on the axial mean and RMS velocities was found to be significant near the leading edge of the rotors causing an increase in the mean and RMS velocities of the order of 4.2Vp in mean (where Vp is the axial pitched velocity) for male rotor and 5.4Vp for, female rotor and this effect is less pronounced on the flow near the root of the rotor. Moreover, to obtain a better understanding of the flow motion, a high sampling rate pressure transducer was used to provide the internal angular static pressure variation. These measurements are used to validate the in-house CFD model of the fluid flow within twin screw compressors which, in turn, allows reliable optimisation of various compressor designs.

  19. Flow and pressure characteristics within a screw compressor

    Energy Technology Data Exchange (ETDEWEB)

    Guerrato, D; Nouri, J M; Stosic, N; Arcoumanis, C [Centre for Energy and the Environment, School of Engineering and Mathematical Sciences, City University, Northampton Square, London, EC1V OHB (United Kingdom)

    2007-10-15

    The angle-resolved mean and turbulence characteristics of the axial air flow inside a screw compressor with both male and female rotors have been measured, using a laser Doppler velocimeter (LDV) with high spatial and temporal resolution at different radial and axial locations for speeds of 800-1600 rpm, discharge pressures of 1-1.6 bar and discharge temperatures of 33-90{sup 0}C. The velocity measurements were performed through a special transparent window fixed near the discharge port. The results confirmed the ability of the LDV technique to characterise the flow inside the compressor working chamber; an angular resolution of 1.5{sup 0} was able to fully describe the velocity field within the machine. The flow variation between the different working chambers was established as well as the spatial variation of the axial mean velocity and turbulence velocity fluctuation within the working chamber. The effect of discharge port opening on the axial mean and RMS velocities was found to be significant near the leading edge of the rotors causing an increase in the mean and RMS velocities of the order of 4.2V{sub p} in mean (where V{sub p} is the axial pitched velocity) for male rotor and 5.4V{sub p} for, female rotor and this effect is less pronounced on the flow near the root of the rotor. Moreover, to obtain a better understanding of the flow motion, a high sampling rate pressure transducer was used to provide the internal angular static pressure variation. These measurements are used to validate the in-house CFD model of the fluid flow within twin screw compressors which, in turn, allows reliable optimisation of various compressor designs.

  20. Flow and pressure characteristics within a screw compressor

    International Nuclear Information System (INIS)

    Guerrato, D; Nouri, J M; Stosic, N; Arcoumanis, C

    2007-01-01

    The angle-resolved mean and turbulence characteristics of the axial air flow inside a screw compressor with both male and female rotors have been measured, using a laser Doppler velocimeter (LDV) with high spatial and temporal resolution at different radial and axial locations for speeds of 800-1600 rpm, discharge pressures of 1-1.6 bar and discharge temperatures of 33-90 0 C. The velocity measurements were performed through a special transparent window fixed near the discharge port. The results confirmed the ability of the LDV technique to characterise the flow inside the compressor working chamber; an angular resolution of 1.5 0 was able to fully describe the velocity field within the machine. The flow variation between the different working chambers was established as well as the spatial variation of the axial mean velocity and turbulence velocity fluctuation within the working chamber. The effect of discharge port opening on the axial mean and RMS velocities was found to be significant near the leading edge of the rotors causing an increase in the mean and RMS velocities of the order of 4.2V p in mean (where V p is the axial pitched velocity) for male rotor and 5.4V p for, female rotor and this effect is less pronounced on the flow near the root of the rotor. Moreover, to obtain a better understanding of the flow motion, a high sampling rate pressure transducer was used to provide the internal angular static pressure variation. These measurements are used to validate the in-house CFD model of the fluid flow within twin screw compressors which, in turn, allows reliable optimisation of various compressor designs

  1. Investigations on pneumatically forced-actuated compressor valves

    Science.gov (United States)

    Stöckel, Christian; Thomas, Christiane; Nickl, Jörg; Hesse, Ullrich

    2017-08-01

    In the present paper the performance of a novel designed valve for reciprocating piston machines is investigated, which makes existing compressors utilizable for operating as expander. Three design parameters were identified as critical for the valves performance particularly in forced actuated mode. Within a numerical simulation a study on the crucial geometrical parameters, the influence could be observed. Afterwards the experimental setup for the integral test of the valve design is presented and also additional tests for single valve components.

  2. Numerical study on oil supply system of a rotary compressor

    International Nuclear Information System (INIS)

    Wu, Jianhua; Wang, Gang

    2013-01-01

    The oil supply system is a crucial reliability issue for rotary compressors. This paper provides a general method for analyzing the oil supply system of a rotary compressor by using computational fluid dynamics (CFD). The process includes establishing the physical model, dividing computational grid, setting boundary conditions, calculating leakage rates through the roller end clearances, translating the dynamic issue into the static issue and so on. Validation of the rationality of the oil supply system model has been made by the measurement of the main bearing oil flow rates. The effects of operating conditions of the compressor, the oil level height of the oil sump and the main design parameters of the oil supply system on the oil supply characteristics are analyzed by numerical simulation. It is found that the main bearing oil flow rate varies circularly along with the rotation of the shaft. The shape and inclination angle of the spiral groove also influence the main bearing oil flow rate. The oil leakage rates through the roller end clearances depend largely on the operating conditions. In addition, the oil level height of the oil sump has a huge effect on the total oil flow rate. -- Highlights: • A CFD method for analyzing the oil supply system of rotary compressor is presented. • Leakage through the roller end clearances depends on the operating condition. • Groove shape and inclination angle are the main design parameters of spiral grooves. • A parabolic interface of oil and gas can be formed in the gallery of the shaft. • Single-flow model and steady solver can be applied to the oil supply system

  3. Stability Analysis for Rotating Stall Dynamics in Axial Flow Compressors

    Science.gov (United States)

    1999-01-01

    modes determines collectively local stability of the compressor model. Explicit conditions are obtained for local stability of rotating stall which...critical modes determines the stability for rotating stall collectively . We point out that although in a special case our stability condition for...strict crossing assumption implies that the zero solution changes its stability as ~, crosses ~’c. For instance, odk (yc ) > 0 implies that the zero

  4. Uncertainty analysis of thermal quantities measurement in a centrifugal compressor

    Science.gov (United States)

    Hurda, Lukáš; Matas, Richard

    2017-09-01

    Compressor performance characteristics evaluation process based on the measurement of pressure, temperature and other quantities is examined to find uncertainties for directly measured and derived quantities. CFD is used as a tool to quantify the influences of different sources of uncertainty of measurements for single- and multi-thermocouple total temperature probes. The heat conduction through the body of the thermocouple probe and the heat-up of the air in the intake piping are the main phenomena of interest.

  5. Computational analysis of supercritical carbon dioxide flow around a turbine and compressor BLADE

    International Nuclear Information System (INIS)

    Kim, Tae W.; Kim, Nam H.; Suh, Kune Y.; Kim, Seung O.

    2007-01-01

    The turbine and compressor isentropic efficiencies are one of the major parameters affecting the overall Brayton cycle efficiency. Thus, the optimal turbine and compressor design should contribute to the economics of future nuclear fission and fusion energy systems. A computation analysis was performed utilizing CFX for the supercritical carbon dioxide (SCO 2 ) flow around a turbine and compressor blade to check on the potential efficiency of the turbine and compressor which determine such basic design values as the blade (or impeller) and nozzle (or diffuser) types, blade height, and minimum and maximum radii of the hub and tip. Basic design values of the turbine and compressor blades based on the Argonne National Laboratory (ANL) design code was generated by ANSYS BladeGen TM . The boundary conditions were based on the KALIMER-600 secondary loop. Optimal SCO 2 turbine and compressor blades were developed for high efficiency of 90% by the computational analysis. (author)

  6. Stage-by-Stage and Parallel Flow Path Compressor Modeling for a Variable Cycle Engine

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph W.; Cheng, Larry

    2015-01-01

    This paper covers the development of stage-by-stage and parallel flow path compressor modeling approaches for a Variable Cycle Engine. The stage-by-stage compressor modeling approach is an extension of a technique for lumped volume dynamics and performance characteristic modeling. It was developed to improve the accuracy of axial compressor dynamics over lumped volume dynamics modeling. The stage-by-stage compressor model presented here is formulated into a parallel flow path model that includes both axial and rotational dynamics. This is done to enable the study of compressor and propulsion system dynamic performance under flow distortion conditions. The approaches utilized here are generic and should be applicable for the modeling of any axial flow compressor design.

  7. Characterization and Performance Testing of Natural Gas Compressors for Residential and Commercial Applications

    Science.gov (United States)

    Zhang, Xinye; Groll, Eckhard A.; Bethel, Dylan

    2017-08-01

    Relatively little information is available in the literature with respect to the performance of compressors used during the dynamic charging process of a tank. Therefore, work presented in this paper shows the measurement results of performance testing of a natural gas compressor and analyses the compressor characterization based on the experimental data. Initial tests were conducted using air and carbon dioxide given the thermodynamic similarities between these fluids and natural gas. Finally, a new test stand was specifically designed and built for compressor dynamic testing using pipeline natural gas (NG) and the compressor reliability has been evaluated inside an explosion-proof engine test cell. Reliability tests at standard operating conditions monitored the performance consistency of the compressors over the testing period and the testing consisted of a series of tank charges aimed at evaluating the maximum operating temperature as well as the mass flow rate in the system.

  8. Trends in high performance compressors for petrochemical and natural gas industry in China

    Science.gov (United States)

    Zhao, Yuanyang; Li, Liansheng

    2015-08-01

    Compressors are the key equipment in the petrochemical and natural gas industry system. The performance and reliability of them are very important for the process system. The application status of petrochemical & natural gas compressors in China is presented in this paper. The present status of design and operating technologies of compressors in China are mentioned in this paper. The turbo, reciprocating and twin screw compressors are discussed. The market demands for different structure compressors in process gas industries are analysed. This paper also introduces the research and developments for high performance compressors in China. The recent research results on efficiency improvement methods, stability improvement, online monitor and fault diagnosis will also be presented in details.

  9. Dynamic Model of Centrifugal Compressor for Prediction of Surge Evolution and Performance Variations

    International Nuclear Information System (INIS)

    Jung, Mooncheong; Han, Jaeyoung; Yu, Sangseok

    2016-01-01

    When a control algorithm is developed to protect automotive compressor surges, the simulation model typically selects an empirically determined look-up table. However, it is difficult for a control oriented empirical model to show surge characteristics of the super charger. In this study, a dynamic supercharger model is developed to predict the performance of a centrifugal compressor under dynamic load follow-up. The model is developed using Simulink® environment, and is composed of a compressor, throttle body, valves, and chamber. Greitzer’s compressor model is used, and the geometric parameters are achieved by the actual supercharger. The simulation model is validated with experimental data. It is shown that compressor surge is effectively predicted by this dynamic compressor model under various operating conditions.

  10. Speed and surge control for a lower order centrifugal compressor model

    Directory of Open Access Journals (Sweden)

    Jan T. Gravdahl

    1998-01-01

    Full Text Available A model of a variable speed centrifugal compression system is presented. The model is based on the work of Greitzer (1976, but the compressor characteristic is developed by modelling the losses in the compressor. For surge control, a close coupled valve is employed. This valve is placed immediately downstream of the compressor, and the pressure drop over the valve is used as the control variable. This makes it possible to manipulate the shape of the equivalent compressor, consisting of compressor and valve. The speed of the compressor is controlled with a PI-controller. Semi-global exponential stability of the model with the proposed controllers is proven by the use of Lyapunovs theorem.

  11. Dynamic Model of Centrifugal Compressor for Prediction of Surge Evolution and Performance Variations

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Mooncheong; Han, Jaeyoung; Yu, Sangseok [Chungnam National Univ., Daejeon (Korea, Republic of)

    2016-05-15

    When a control algorithm is developed to protect automotive compressor surges, the simulation model typically selects an empirically determined look-up table. However, it is difficult for a control oriented empirical model to show surge characteristics of the super charger. In this study, a dynamic supercharger model is developed to predict the performance of a centrifugal compressor under dynamic load follow-up. The model is developed using Simulink® environment, and is composed of a compressor, throttle body, valves, and chamber. Greitzer’s compressor model is used, and the geometric parameters are achieved by the actual supercharger. The simulation model is validated with experimental data. It is shown that compressor surge is effectively predicted by this dynamic compressor model under various operating conditions.

  12. Application of Pyrolysis - Gas Chromatography/Mass Spectrometry in Failure Analysis in the Automotive Industry

    OpenAIRE

    Kusch, Peter (Dr.)

    2015-01-01

    This book chapter describes application examples of gas chromatography/mass spectrometry and pyrolysis – gas chromatography/mass spectrometry in failure analysis for the identification of chemical materials like mineral oils and nitrile rubber gaskets. Furthermore, failure cases demanding identification of polymers/copolymers in fouling on the compressor wall of a car air conditioner and identification of fouling on the surface of a bearing race from the automotive industry are demonstr...

  13. Description of Supercritical CO{sub 2} Compressor Experiment Loop

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Je Kyoung; Lee, Jeong Ik; Ahn, Yoonhan; Kim, Seong Gu [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Cha, Je Eun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    The full scope of SCIEL project is to demonstrate high efficiency with simple recuperated cycle layout or recompressing layout, which the final cycle layout will be determined by the obtained compressor performance data. As a part of SCIEL project, S-CO{sub 2} compressor experiment facility has been constructed in KAERI. In this paper, current status of S-CO{sub 2} compressor experiment loop will be reviewed. With the growing interest in developing an advanced nuclear power plant, power conversion cycle innovation has been the part of this effort to secure high economics and enhanced safety. One of the main activities of power conversion cycle innovation is the development of Supercritical CO{sub 2} Brayton cycle technology. S-CO{sub 2} Brayton cycle concept was suggested in 1960s but the development and realization of the technology has been delayed up to now. In Korea, KAIST, KAERI and POSTECH are conducting research and development of Korean S-CO{sub 2} Brayton cycle technology by erecting the Supercritical CO{sub 2} Integral Experiment Loop (SCIEL)

  14. Simulation of Casing Treatments of a Transonic Compressor Stage

    Directory of Open Access Journals (Sweden)

    M. Hembera

    2008-01-01

    Full Text Available This article presents the study of casing treatments on an axial compressor stage for improving stability and enhancing stall margin. So far, many simulations of casing treatments on single rotor or rotor-stator configurations were performed. But as the application of casing treatments in engines will be in a multistage compressor, in this study, the axial slots are applied to a typical transonic first stage of a high-pressure 4.5-stage compressor including an upstream IGV, rotor, and stator. The unsteady simulations are performed with a three-dimensional time accurate Favre-averaged Navier-stokes flow solver. In order to resolve all important flow mechanisms appearing through the use of casing treatments, a computational multiblock grid consisting of approximately 2.4 million nodes was used for the simulations. The configurations include axial slots in 4 different variations with an axial extension ranging into the blade passage of the IGV. Their shape is semicircular with no inclination in circumferential direction. The simulations proved the effectiveness of casing treatments with an upstream stator. However, the results also showed that the slots have to be carefully positioned relative to the stator location.

  15. Centrifugal compressor shape modification using a proposed inverse design method

    International Nuclear Information System (INIS)

    Niliahmadabadi, Mahdi; Poursadegh, Farzad

    2013-01-01

    This paper is concerned with a quasi-3D design method for the radial and axial diffusers of a centrifugal compressor on the meridional plane. The method integrates a novel inverse design algorithm, called ball-spine algorithm (BSA), and a quasi-3D analysis code. The Euler equation is solved on the meridional plane for a numerical domain, of which unknown boundaries (hub and shroud) are iteratively modified under the BSA until a prescribed pressure distribution is reached. In BSA, unknown walls are composed of a set of virtual balls that move freely along specified directions called spines. The difference between target and current pressure distributions causes the flexible boundary to deform at each modification step. In validating the quasi-3D analysis code, a full 3D Navier-Stokes code is used to analyze the existing and designed compressors numerically. Comparison of the quasi-3D analysis results with full 3D analysis results shows viable agreement. The 3D numerical analysis of the current compressor shows a huge total pressure loss on the 90 .deg. bend between the radial and axial diffusers. Geometric modification of the meridional plane causes the efficiency to improve by about 10%.

  16. A new Wankel-type compressor and vacuum pump

    Science.gov (United States)

    Garside, D. W.

    2017-08-01

    When the Wankel principles were first published in the early 1950s most of the initial work was aimed at developing a compressor . At that time many of the characteristics appeared to promise a superior machine than hitherto known. However, all the early designs resulted in a high value for the minimum clearance volume (CV) and this problem was never overcome. Knowledge now gained from the development and manufacture of the Wankel engine has enabled the evolution of a new compressor concept where the rotor flank, radially very close-fitting over its central area, provides gas sealing with the housing bore. The rotor has an increased radial clearance towards the apices which makes the machine practical to manufacture. The ‘nesting’ of the rotor flank with the housing bore at the end of the exhaust stroke results in an extremely small CV. This machine promises to possess an exceptional combination of all the attributes which are important in achieving high energy efficiency in positive-displacement compressors and vacuum pumps: - near-zero CV - low mechanical friction losses - low internal gas leakage (assisted via oil flooding) - high volumetric efficiency. In addition it is compact, lightweight, vibration-free, consists of few components, and can be built in any chamber size. The Paper discusses the features and characteristics of the design.

  17. Minimisation of pressure pulsations in the screw compressor discharge piping

    Energy Technology Data Exchange (ETDEWEB)

    Zaytsev, D. [Grasso GmbH Refrigeration Technology, Berlin (Germany). R and D Screw Compressors

    2006-07-01

    A problem of noise and vibration in the piping between the screw compressor and oil separator arises if the natural gas pulsations in the piping get in the resonance with the pulsations sent by the compressor. Several typical piping geometries such as a short and a long pipe with the open end and a short pipe with agglomerator have been studied to evaluate the natural frequency of the gas column. It was found that because of the wave reflection from the open pipe end the gas in such a pipe has several natural frequencies dependent on the sound speed and on the pipe length. Since the sound speed of various refrigerants differs significantly, the resonance pipe length will also vary strongly from one refrigerant to another. Hence, to avoid the resonance a separate examination for each refrigerant would be required at the compressor package design stage. Unlike open ended pipes, in the pipe with agglomerator the wave reflection at the agglomerator side is reduced. This allows using of one standard discharge pipe geometry resonance-free independent on the refrigerant. (orig.)

  18. Experimental investigation on a high subsonic compressor cascade flow

    Directory of Open Access Journals (Sweden)

    Zhang Haideng

    2015-08-01

    Full Text Available With the aim of deepening the understanding of high-speed compressor cascade flow, this paper reports an experimental study on NACA-65 K48 compressor cascade with high subsonic inlet flow. With the increase of passage pressurizing ability, endwall boundary layer behavior is deteriorated, and the transition zone is extended from suction surface to the endwall as the adverse pressure gradient increases. Cross flow from endwall to midspan, mixing of corner boundary layer and the main stream, and reversal flow on the suction surface are caused by corner separation vortex structures. Passage vortex is the main corner separation vortex. During its movement downstream, the size grows bigger while the rotating direction changes, forming a limiting circle. With higher incidence, corner separation is further deteriorated, leading to higher flow loss. Meanwhile, corner separation structure, flow mixing characteristics and flow loss distribution vary a lot with the change of incidence. Compared with low aspect-ratio model, corner separation of high aspect-ratio model moves away from the endwall and is more sufficiently developed downstream the cascade. Results obtained present details of high-speed compressor cascade flow, which is rare in the relating research fields and is beneficial to mechanism analysis, aerodynamic optimization and flow control design.

  19. Static analysis of triple-effect adsorption refrigeration with compressor

    Directory of Open Access Journals (Sweden)

    Fumi Watanabe

    2017-03-01

    Full Text Available In order to improve the efficiency of the adsorption refrigeration cycle, this study proposes a triple-effect adsorption refrigeration cycle equipped with a compressor. This cycle can run in order to create a large variation in adsorbent concentration range by the compressor, even if there is little temperature variation in the desorption and adsorption processes. The objective of this study is to clarify the effect that regulating adsorption pressure using a compressor has on the adsorption refrigeration cycle, and to that end cycle efficiency was calculated using a static analysis based on a state of equilibrium. As a results from the simulation, the triple-effect cycles can operate by regulating adsorption pressure. Both COP and exergy efficiency can be improved by a factor of 1.2 if the cycled is regulated the adsorption pressure of each cycle rather than using a shared adsorption pressure. For heat sources in the temperature range of 70–100 °C, this method is superior in terms of COP and exergy efficiency. COP values of approximately 1.7–1.8 can be obtained, which is three times higher than single-effect cycles. The triple-effect cycles have one-third the SCE of single-effect cycles but about the same SCE as double-effect cycles.

  20. Optimization Design of IGV Profile in Centrifugal Compressor

    Directory of Open Access Journals (Sweden)

    Qi Sun

    2017-01-01

    Full Text Available Variable inlet guide vane (IGV is used to control the mass flow and generate prewhirl in centrifugal compressors. The efficient operation of IGV is limited to the range of aerodynamic characteristics of their vane profiles. In order to find out the best vane profile for IGV regulation, the modern optimization method was adopted to optimize the inlet guide vane profile. The main methodology idea was to use artificial neural network for continuous fitness evaluation and use genetic algorithm for global optimization. After optimization, the regulating performance of IGV has improved significantly, the prewhirl ability has been enhanced greatly, and the pressure loss has been reduced. The mass flow and power of compressor reduced by using the optimized guide vane at large setting angles, and the efficiency increased significantly; the flow field distribution has been improved obviously, since the nonuniform distribution of flow and flow separation phenomenon greatly weakened or even completely disappeared. The achievement of this research can effectively improve the regulation ability of IGV and the performance of compressor.

  1. Centrifugal compressor shape modification using a proposed inverse design method

    Energy Technology Data Exchange (ETDEWEB)

    Niliahmadabadi, Mahdi [Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Poursadegh, Farzad [Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2013-03-15

    This paper is concerned with a quasi-3D design method for the radial and axial diffusers of a centrifugal compressor on the meridional plane. The method integrates a novel inverse design algorithm, called ball-spine algorithm (BSA), and a quasi-3D analysis code. The Euler equation is solved on the meridional plane for a numerical domain, of which unknown boundaries (hub and shroud) are iteratively modified under the BSA until a prescribed pressure distribution is reached. In BSA, unknown walls are composed of a set of virtual balls that move freely along specified directions called spines. The difference between target and current pressure distributions causes the flexible boundary to deform at each modification step. In validating the quasi-3D analysis code, a full 3D Navier-Stokes code is used to analyze the existing and designed compressors numerically. Comparison of the quasi-3D analysis results with full 3D analysis results shows viable agreement. The 3D numerical analysis of the current compressor shows a huge total pressure loss on the 90 .deg. bend between the radial and axial diffusers. Geometric modification of the meridional plane causes the efficiency to improve by about 10%.

  2. Ultralow temperature helium compressor for Japan Atomic Energy Research Institute

    International Nuclear Information System (INIS)

    Asakura, Hiroshi

    1988-01-01

    Ishikawajima Harima Heavy Industries Co., Ltd. started the development of an ultralow temperature helium compressor for helium liquefaction in 1984 jointly with Japan Atomic Energy Research Institute, and has delivered the first practical machine to the Superconductive Magnet Laboratory of JAERI. For a large superconductive magnet to be used in the stable state for a fusion reactor, conventional superconductive materials (NbTi, NbTi 3 Sn, etc.) must be used, being cooled forcibly with supercritical helium. The supercritical helium which is compressed above the critical pressure of 228 kPa has a stable cooling effect since the thermal conductivity does not change due to the evaporation of liquid helium. In order to maintain the temperature of the supercritical helium below 4 K before it enters a magnet, a heat exchanger is used. The compressor that IHI has developed has the ability to reduce the vapor pressure of liquid helium from atmospheric pressure to 50.7 kPa, and can attain the temperature of 3.5 K. The specification of this single stage centrifugal compressor is: mass flow rate 25 - 64 g/s, speed 80,000 rpm, adiabatic efficiency 62 - 69 %. The structure and the performance are reported. (K.I.)

  3. Modeling of flexible reciprocating compressor considering the crosshead subsidence

    Science.gov (United States)

    Xue, Xiaogang; Liu, Shulin; Sun, Xin

    2018-01-01

    Crank-slider mechanisms are important parts of heavy duty machines, including reciprocating compressors, combustion motors. This paper targets on the dynamic response of the crosshead in a reciprocating compressor, taking into consideration the crosshead deviation from the original level. The traditional model of the compressor is usually a slider-mechanism system without considering the deflection of the crosshead, thus neglecting the influence of the piston rod, which has some flexible features. In this paper, a rigid-flexible model of slider-crank is described theoretically, using the commercial software MATLAB, where the crank, connecting rod and crosshead are treated as rigid bodies, while the piston rod connected to the crosshead is considered as a flexible body. The dynamic response of the mechanism with the crosshead subsidence is discussed detailedly in this paper. After calculated theoretically, the MATLAB simulation showed that the dynamic response of the crosshead will be greatly influenced if the crosshead subsided from the original level. Also, the influence of the crosshead subsidence was also investigated, and some extra vibration of the crosshead arises.

  4. Analytical model for an electrostatically actuated miniature diaphragm compressor

    International Nuclear Information System (INIS)

    Sathe, Abhijit A; Groll, Eckhard A; Garimella, Suresh V

    2008-01-01

    This paper presents a new analytical approach for quasi-static modeling of an electrostatically actuated diaphragm compressor that could be employed in a miniature scale refrigeration system. The compressor consists of a flexible circular diaphragm clamped at its circumference. A conformal chamber encloses the diaphragm completely. The membrane and the chamber surfaces are coated with metallic electrodes. A potential difference applied between the diaphragm and the chamber pulls the diaphragm toward the chamber surface progressively from the outer circumference toward the center. This zipping actuation reduces the volume available to the refrigerant gas, thereby increasing its pressure. A segmentation technique is proposed for analysis of the compressor by which the domain is divided into multiple segments for each of which the forces acting on the diaphragm are estimated. The pull-down voltage to completely zip each individual segment is thus obtained. The required voltage for obtaining a specific pressure rise in the chamber can thus be determined. Predictions from the model compare well with other simulation results from the literature, as well as to experimental measurements of the diaphragm displacement and chamber pressure rise in a custom-built setup

  5. Helium compressor aerodynamic design considerations for MHTGR circulators

    International Nuclear Information System (INIS)

    McDonald, C.F.

    1988-01-01

    Compressor aerodynamic design considerations for both the main and shutdown cooling circulators in the Modular High-Temperature Gas-Cooled Reactor (MHTGR) plant are addressed in this paper. A major selection topic relates to the impeller type (i.e., axial or radial flow), and the aerothermal studies leading to the selection of optimum parameters are discussed. For the conceptual designs of the main and shutdown cooling circulators, compressor blading geometries were established and helium gas flow paths defined. Both circulators are conservative by industrial standards in terms of aerodynamic and structural loading, and the blade tip speeds are particularly modest. Performance characteristics are presented, and the designs embody margin to ensure that pressure-rise growth potential can be accomodated should the circuit resistance possibly increase as the plant design advances. The axial flow impeller for the main circulator is very similar to the Fort St. Vrain (FSV) helium compressor which performs well. A significant technology base exists for the MHTGR plant circulators, and this is highlighted in the paper. (author). 15 refs, 16 figs, 12 tabs

  6. Refrigerator with variable capacity compressor and cycle priming action through capacity control and associated methods

    Science.gov (United States)

    Gomes, Alberto Regio; Litch, Andrew D.; Wu, Guolian

    2016-03-15

    A refrigerator appliance (and associated method) that includes a condenser, evaporator and a multi-capacity compressor. The appliance also includes a pressure reducing device arranged within an evaporator-condenser refrigerant circuit, and a valve system for directing or restricting refrigerant flow through the device. The appliance further includes a controller for operating the compressor upon the initiation of a compressor ON-cycle at a priming capacity above a nominal capacity for a predetermined or calculated duration.

  7. Techno-Economic Analysis of Gas Turbine Compressor Washing to Combat Fouling

    OpenAIRE

    Abass, Kabir Oliade

    2015-01-01

    Among the major deterioration problems a gas turbine encountered while in operation is compressor blade fouling. This is the accumulation and adhesion of dirt and sediment on the compressor blade which contributes between 70 to 85% of gas turbine performance loss. Fouling reduces turbine air mass flow capacity, compressor pressure ratio and overall gas turbine efficiency. In most cases, its effect does not manifest immediately in gas turbine power output and efficiency since they are not meas...

  8. Design, Test, and Evaluation of a Transonic Axial Compressor Rotor with Splitter Blades

    Science.gov (United States)

    2013-09-01

    INTRODUCTION A. MOTIVATION Over the course of turbomachinery history splitter vanes have been used extensively in centrifugal compressors . Axial...TEST, AND EVALUATION OF A TRANSONIC AXIAL COMPRESSOR ROTOR WITH SPLITTER BLADES by Scott Drayton September 2013 Dissertation Co...AXIAL COMPRESSOR ROTOR WITH SPLITTER BLADES 5. FUNDING NUMBERS 6. AUTHOR(S) Scott Drayton 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES

  9. Virtual Refrigerant Mass Flow and Power Sensors for Variable-Speed Compressors

    OpenAIRE

    Kim, Woohyun; Braun, James E.

    2012-01-01

    The use of variable-speed compressors in heat pumps and air conditioners has increased in recent years in order to improve comfort and energy efficiency. At the same time, there is a trend towards embedding more sensors in this type of equipment to facilitate real-time energy monitoring and diagnostics. Although compressor mass flow rate and power consumption are useful indices for performance monitoring and diagnostics, they are expensive to measure. The virtual variable-speed compressor sen...

  10. Performance Characteristics of a 4 × 6 Oil-Free Twin-Screw Compressor

    OpenAIRE

    Sun-Seok Byeon; Jae-Young Lee; Youn-Jea Kim

    2017-01-01

    The screw compressor in the early stage of development is generally known as the oil-injection type. However, escalating environmental problems and advances in electronic components have spurred continuous R & D to minimize the oil content in compressed air. The oil-free twin-screw compressor is continuously compressed by inner volumetric change between rotors and casing. For this reason, in order to predict the overall performance of the screw compressor at the early stage of the design ...

  11. Thirty years of screw compressors for helium; Dreissig Jahre Schraubenkompressoren fuer Helium

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, H. [Kaeser Kompressoren GmbH, Coburg (Germany). Technisches Buero/Auftragskonstruktion

    2007-07-01

    KAESER helium compressors, as well as their other industrial compressors, will be further developed with the intention to improve the availability and reliability of helium liquefaction systems. Further improvement of compressor and control system efficiency will ensure a low and sustainable operating cost. Fast supply of replacement parts with several years of warranty is ensured by a world-wide distribution system and is also worked on continuously. (orig.)

  12. Modelling and Experimental Investigation of Unsteady Behaviour of a Screw Compressor Plant

    OpenAIRE

    Chukanova, Ekatarina; Stosic, Nikola; Kovacevic, Ahmed

    2014-01-01

    Majority of air compressor plants installed worldwide operate permanently under unsteady conditions, however, there is still a lack of published papers which describe the plant dynamics and offer quantification parameters of the phenomenon. An experimental and analytical study of a screw compressor operation under unsteady conditions has been carried out. For this purpose a one dimensional model of the processes within a screw compressor based on the differential equations of conservation of ...

  13. Noise analysis of fluid-valve system in a linear compressor using CAE

    International Nuclear Information System (INIS)

    Lee, Jun Ho; Jeong, Weui Bong; Kim, Dang Ju

    2009-01-01

    A linear compressor in a refrigerator uses piston motion to transfer refrigerant so its efficiency is higher than a previous reciprocal compressor. Because of interaction between refrigerant and valves system in the linear compressor, however, noise has been a main issue. In spite of doing many experimental researches, there is no way to rightly predict the noise. In order to solve this limitation, the CAE analysis is applied. For giving credit to these computational data, all of the data are experimentally validated.

  14. Preliminary Design and Model Assessment of a Supercritical CO2 Compressor

    Directory of Open Access Journals (Sweden)

    Zhiyuan Liu

    2018-04-01

    Full Text Available The compressor is a key component in the supercritical carbon dioxide (SCO2 Brayton cycle. In this paper, the authors designed a series of supercritical CO2 compressors with different parameters. These compressors are designed for 100 MWe, 10 MWe and 1 MWe scale power systems, respectively. For the 100 MWe SCO2 Brayton cycle, an axial compressor has been designed by the Smith chart to test whether an axial compressor is suitable for the SCO2 Brayton cycle. Using a specific speed and a specific diameter, the remaining two compressors were designed as centrifugal compressors with different pressure ratios to examine whether models used for air in the past are applicable to SCO2. All compressors were generated and analyzed with internal MATLAB programs coupled with the NIST REFPROP database. Finally, the design results are all checked by numerical simulations due to the lack of reliable experimental data. Research has found that in order to meet the de Haller stall criterion, axial compressors require a considerable number of stages, which introduces many additional problems. Thus, a centrifugal compressor is more suitable for the SCO2 Brayton cycle, even for a 100 MWe scale system. For the performance prediction model of a centrifugal compressor, the stall predictions are compared with steady numerical calculation, which indicates that past stall criteria may also be suitable for SCO2 compressors, but more validations are needed. However, the accuracy of original loss models is found to be inadequate, particularly for lower flow and higher pressure ratio cases. Deviations may be attributed to the underestimation of clearance loss according to the result of steady simulation. A modified model is adopted which can improve the precision to a certain extent, but more general and reasonable loss models are needed to improve design accuracy in the future.

  15. Design and prototyping of an ionic liquid piston compressor as a new generation of compressors for hydrogen refueling stations

    DEFF Research Database (Denmark)

    Arjomand Kermani, Nasrin

    to investigate the heat transfer phenomena inside the compression chamber; the system performance is evaluated, followed by the design process. The model is developed based on the mass and energy balance of the hydrogen, and liquid bounded by the wall of the compression chamber. Therefore, at each time step...... and positional node, the model estimates the pressure and temperature of the hydrogen and liquid, the temperature of the compression chamber wall, and the amount of heat extracted from the hydrogen directly at the interface between the hydrogen and liquid, and through the wall. The results indicate......, fabrication, and control of the prototype is described in the presented work. The new compressor design has high potential to be used as an alternative to the conventional reciprocating compressors in hydrogen refueling stations, as it provides a simpler design with lower manufacturing costs, higher...

  16. The improvement of screw compressor performance using a newly developed rotor profile

    International Nuclear Information System (INIS)

    Kishi, Takayuki; Nishio, Toshio; Matsui, Akira; Ino, Nobumi

    1994-01-01

    An oil-compression phenomenon occurs at two portions of a conventional oil injected screw compressor that degrades the isothermal efficiency of the screw compressor. Hence a new screw rotor profile and lubricant have been developed in order to avoid the above oil-compression phenomena. Mycom and Fermi National Accelerator Laboratory have measured the performance of a new Mycom compound type screw compressor 2016C using the new profile rotors and the new lubricant. In the experiments, a 33% enhancement rate in the isothermal efficiency of the new screw compressor installed in Fermilab was achieved

  17. Dynamic modelling and PID loop control of an oil-injected screw compressor package

    Science.gov (United States)

    Poli, G. W.; Milligan, W. J.; McKenna, P.

    2017-08-01

    A significant amount of time is spent tuning the PID (Proportional, Integral and Derivative) control loops of a screw compressor package due to the unique characteristics of the system. Common mistakes incurred during the tuning of a PID control loop include improper PID algorithm selection and unsuitable tuning parameters of the system resulting in erratic and inefficient operation. This paper details the design and development of software that aims to dynamically model the operation of a single stage oil injected screw compressor package deployed in upstream oil and gas applications. The developed software will be used to assess and accurately tune PID control loops present on the screw compressor package employed in controlling the oil pressures, temperatures and gas pressures, in a bid to improve control of the operation of the screw compressor package. Other applications of the modelling software will include its use as an evaluation tool that can estimate compressor package performance during start up, shutdown and emergency shutdown processes. The paper first details the study into the fundamental operational characteristics of each of the components present on the API 619 screw compressor package and then discusses the creation of a dynamic screw compressor model within the MATLAB/Simulink software suite. The paper concludes by verifying and assessing the accuracy of the created compressor model using data collected from physical screw compressor packages.

  18. Available pressure amplitude of linear compressor based on phasor triangle model

    Science.gov (United States)

    Duan, C. X.; Jiang, X.; Zhi, X. Q.; You, X. K.; Qiu, L. M.

    2017-12-01

    The linear compressor for cryocoolers possess the advantages of long-life operation, high efficiency, low vibration and compact structure. It is significant to study the match mechanisms between the compressor and the cold finger, which determines the working efficiency of the cryocooler. However, the output characteristics of linear compressor are complicated since it is affected by many interacting parameters. The existing matching methods are simplified and mainly focus on the compressor efficiency and output acoustic power, while neglecting the important output parameter of pressure amplitude. In this study, a phasor triangle model basing on analyzing the forces of the piston is proposed. It can be used to predict not only the output acoustic power, the efficiency, but also the pressure amplitude of the linear compressor. Calculated results agree well with the measurement results of the experiment. By this phasor triangle model, the theoretical maximum output pressure amplitude of the linear compressor can be calculated simply based on a known charging pressure and operating frequency. Compared with the mechanical and electrical model of the linear compressor, the new model can provide an intuitionistic understanding on the match mechanism with faster computational process. The model can also explain the experimental phenomenon of the proportional relationship between the output pressure amplitude and the piston displacement in experiments. By further model analysis, such phenomenon is confirmed as an expression of the unmatched design of the compressor. The phasor triangle model may provide an alternative method for the compressor design and matching with the cold finger.

  19. Thermodynamic properties of UF sub 6 measured with a ballistic piston compressor

    Science.gov (United States)

    Sterritt, D. E.; Lalos, G. T.; Schneider, R. T.

    1973-01-01

    From experiments performed with a ballistic piston compressor, certain thermodynamic properties of uranium hexafluoride were investigated. Difficulties presented by the nonideal processes encountered in ballistic compressors are discussed and a computer code BCCC (Ballistic Compressor Computer Code) is developed to analyze the experimental data. The BCCC unfolds the thermodynamic properties of uranium hexafluoride from the helium-uranium hexafluoride mixture used as the test gas in the ballistic compressor. The thermodynamic properties deduced include the specific heat at constant volume, the ratio of specific heats for UF6, and the viscous coupling constant of helium-uranium hexafluoride mixtures.

  20. Correct integration of compressors and expanders in above ambient heat exchanger networks

    International Nuclear Information System (INIS)

    Fu, Chao; Gundersen, Truls

    2016-01-01

    The Appropriate Placement concept (also referred to as Correct Integration) is fundamental in Pinch Analysis. The placement of reactors, distillation columns, evaporators, heat pumps and heat engines in heat exchanger networks is well established. The placement of pressure changing equipment such as compressors and expanders is complex and less discussed in literature. A major difficulty is that both heat and work (not only heat) are involved. The integration of compressors and expanders separately into heat exchanger networks was recently investigated. A set of theorems were proposed for assisting the design. The problem is even more complex when both compressors and expanders are to be integrated. An important concern is about the sequence of integration with compressors and expanders, i.e. should compressors or expanders be implemented first. This problem is studied and a new theorem is formulated related to the Correct Integration of both compressors and expanders in above ambient heat exchanger networks. The objective is to minimize exergy consumption for the integrated processes. A graphical design methodology is developed for the integration of compressors and expanders into heat exchanger networks above ambient temperature. - Highlights: • The correct integration of compressors and expanders in heat exchanger networks is studied. • A theorem is proposed for heat integration between compressors and expanders. • The total exergy consumption is minimized.

  1. Performance improvement of standard turbo-compressor; Han`yo turbo asshukuki no seino kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Hokari, T.; Hasegawa, K.; Ozaki, S.; Majima, K. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1999-05-01

    Abradable materials are soft and cause no contact damage to the impeller of the turbo-compressor. Using such materials for the inlet casing facing to the impeller allows very small clearances between the impeller and inlet casing, thus improving the compressor efficiency by 10% over conventional types. Changing the area of abradable material applied to the inlet casing identified the optimum area in which decrease of the compressor surge margin is minimized and efficiency is improved by 10%. As a result, turbo-compressors have the best performance when the abradable materials are applied from the impeller outlet to two-thirds of the forward location of the inlet casing. (author)

  2. Determination of Pressure Fluctuations in Rotor Bundle of Centrifugal Compressor at Critical Conditions of Operation

    Science.gov (United States)

    Levashov, V. A.; Lyubchenko, K. Yu

    2017-08-01

    This article describes the physical processes that occur in the stage flow part of the compressor while it is operating and can create conditions for the occurrence of forced vibrations, which in turn can lead to the destruction of the impellers. Critical conditions of compressor operation are determined. To understand that critical condition of operation is cause of the destruction of the impellers, transient CFD analysis was carried for test stage of compressor. The obtained pressure fluctuation amplitudes allow to evaluate the critical conditions of compressor operation.

  3. Fast 4-2 Compressor of Booth Multiplier Circuits for High-Speed RISC Processor

    Science.gov (United States)

    Yuan, S. C.

    2008-11-01

    We use different XOR circuits to optimize the XOR structure 4-2 compressor, and design the transmission gates(TG) 4-2 compressor use single to dual rail circuit configurations. The maximum propagation delay, the power consumption and the layout area of the designed 4-2 compressors are simulated with 0.35μm and 0.25μm CMOS process parameters and compared with results of the synthesized 4-2 circuits, and show that the designed 4-2 compressors are faster and area smaller than the synthesized one.

  4. Dual capacity compressor with reversible motor and controls arrangement therefor

    Science.gov (United States)

    Sisk, Francis J.

    1980-12-02

    A hermetic reciprocating compressor such as may be used in heat pump applications is provided for dual capacity operation by providing the crankpin of the crankshaft with an eccentric ring rotatably mounted thereon, and with the end of the connecting rod opposite the piston encompassing the outer circumference of the eccentric ring, with means limiting the rotation of the eccentric ring upon the crankpin between one end point and an opposite angularly displaced end point to provide different values of eccentricity depending upon which end point the eccentric ring is rotated to upon the crankpin, and a reversible motor in the hermetic shell of the compressor for rotating the crankshaft, the motor operating in one direction effecting the angular displacement of the eccentric ring relative to the crankpin to the one end point, and in the opposite direction effecting the angular displacement of the eccentric ring relative to the crankpin to the opposite end point, this arrangement automatically giving different stroke lengths depending upon the direction of motor rotation. The mechanical structure of the arrangement may take various forms including at least one in which any impact of reversal is reduced by utilizing lubricant passages and chambers at the interface area of the crankpin and eccentric ring to provide a dashpot effect. In the main intended application of the arrangement according to the invention, that is, in a refrigerating or air conditioning system, it is desirable to insure a delay during reversal of the direction of compressor operation. A control arrangement is provided in which the control system controls the direction of motor operation in accordance with temperature conditions, the system including control means for effecting operation in a low capacity direction or alternatively in a high capacity direction in response to one set, and another set, respectively, of temperature conditions and with timer means delaying a restart of the compressor

  5. FOREWORD: 9th International Conference on Compressors and their Systems

    Science.gov (United States)

    Kovacevic, Ahmed, Prof

    2015-08-01

    The 9th International Conference on Compressors and their Systems will be held in London from 5th - 9th September 2015, and as its Chairman, it is my pleasure to welcome you. This series of conferences started in 1999 organised by the Fluid Machinery Group of the Institution of Mechanical Engineers (IMechE) but since 2009 it has been managed by City University London in conjunction with the IMechE and the Institute of Refrigeration, both of which have been very proactive in promoting it. The Organising committee is grateful for their support and continued encouragement. This year, after rigorous reviewing, we have accepted over 80 technical papers for publication, the highest number in the conference history. On behalf of the organising committee I would like to thank the reviewers for their hard work and assistance. In addition to the main technical sessions, this year we have introduced a third day, specifically for Industry, to consider technology, business and market drivers on compressor developments. The traditional series of the short courses is this year continuing prior to the main event with the second short course/forum on Computational Fluid Dynamics in rotating positive displacement machines. I would like to extend my special thanks to our main sponsors, Holroyd PTG, Howden and Kapp Niels for their continuing support for the conference. With their generous contributions we have managed to keep the conference fees at the same level as in 2013, despite extending it to 3 days and holding it outside the University this year. The welcome reception on Sunday 6th September 2015 is dedicated to the celebration of the 20th anniversary of the Centre for Positive Displacement Compressors Technology which was formed at City University in 1995 with support from the Royal Academy of Engineering and Holroyd; its main aim being to assist British manufacturers of screw compressors. The Centre has since made a significant impact on the screw compressor world, far beyond

  6. Evolution of the Power Conversion Unit Design of the GT-MHR

    International Nuclear Information System (INIS)

    Baxi, C.B.; Perez, E.; Shenoy, A.; Kostin, V.I.; Kodochigov, N.G.; Vasyaev, A.V.; Belov, S.E.; Golovko, V.F.

    2006-01-01

    General Atomics in the USA and Experimental Design Bureau of Machine Building (OKBM) in the Russian Federation are jointly developing a gas turbine modular helium reactor (GT-MHR). The 600 MW(t) reactor is cooled by helium at a pressure of 7 MPa. The power conversion unit (PCU) uses the reactor outlet temperature of 850 deg C in a direct Brayton cycle to achieve an efficiency of about 48%. The PCU consists of a gas turbine, a recuperator, a pre-cooler, a low-pressure compressor, an inter-cooler, and a high-pressure compressor. The turbo machine (TM), including the generator, is mounted on a single vertical shaft. The TM rotates at a speed of 4400 rpm. The asynchronous generator is connected to the turbine by a flexible coupling. The required grid frequency is achieved by a converter. All PCU components are enclosed in a single vessel. TM uses radial and axial electromagnetic bearings (EMB) for support. Catcher bearings (CB) are provided as redundant support for the TM rotor in case of EMBs failure. These design features were determined after a comprehensive study carried out over the last 10 years. This paper describes the evolution of the current PCU design and justification for the choices. (authors)

  7. Heart Failure

    Science.gov (United States)

    ... Other diseases. Chronic diseases — such as diabetes, HIV, hyperthyroidism, hypothyroidism, or a buildup of iron (hemochromatosis) or ... transplantation or support with a ventricular assist device. Prevention The key to preventing heart failure is to ...

  8. Investigation on output capacity control strategy of variable refrigerant flow air conditioning system with multi-compressor

    International Nuclear Information System (INIS)

    Tu, Qiu; Zou, Deqiu; Deng, Chenmian; Zhang, Jie; Hou, Lifeng; Yang, Min; Nong, Guicai; Feng, Yuhai

    2016-01-01

    Highlights: • The control model of compressor output capacity has been built. • The control strategy of compressor switching has been presented. • The switching process of standard compressor has been described. • The characteristics of EER and noise have been presented. • The control strategy and model have been proved by experiments. - Abstract: A set of 14 HP variable refrigerant flow air conditioning system (VRF AC) with multi-compressor has been designed, and the output capacity control strategy of compressor(s) including the switching control model of standard compressor has been built. In the output capacity control model, a certain suction pressure is used as the pressure control target to adjust the output capacity of compressors, and a little pressure fluctuation is taken into account to amend the target pressure. Furthermore, in the compressor switching control model, the most favorable operation frequency region is determined on base of the energy efficiency characteristic and noise characteristic of the compressor. And, in order to solve the large fluctuation problem of the system running and frequent ON-OFF action of the standard compressor, the equal output capacity switching principle can be used to determine the thermo-on and thermo-off switched frequency points, and control the switching process of the compressor. Experiments demonstrate the feasibility of this control strategy to ensure the stability and reliability, improve the energy efficiency and reduce the compressor noise.

  9. Design, fabrication, and test plan of a small centrifugal compressor test model for a supercritical CO2 compressor in the fast reactor power plant

    International Nuclear Information System (INIS)

    Muto, Yasushi; Ishizuka, Takao; Aritomi, Masanori

    2009-01-01

    To clarify the CO 2 compressor performance in the vicinity of the critical point, a research project has begun at Tokyo Institute of Technology based on Japanese government funding. This paper describes the design and fabrication results of a small and high-speed centrifugal test compressor. Drawings of compressor structures such as an impeller and a rotor are presented. Numerical analysis results confirm that a desirable fluid flow distribution and structural integrity with respect to both the vane strength and rotor vibration can be expected. (author)

  10. United States Foreign Policy Failures Toward Revolutionary Iran: Miscalculating Tehran’s Power Projection and Ignoring the National Character of the Iranian People

    Science.gov (United States)

    2010-12-01

    position.36 In 1951, Mosaddeq was elected 34 Roger M. Savory , “Religious Dogma and the...42 Pollack, The Persian Puzzle, 42. 43 Yonah Alexander and Allan Nanes, The United States and Iran: A...Alexander, Yonah, and Allan Nanes. The United States and Iran: A Documentary History. Frederick, Md. : University Publication of America, 1980. Al

  11. Analysis of the reasons for failures of the 1500 MW turbines HP diaphragms on the EDF N4 units. Implementation of a solution

    International Nuclear Information System (INIS)

    Franc, J. C.; Franconville, M.

    2002-01-01

    The full text follows. Diaphragms are major components of an impulse type steam turbine since they hold the fixed blades which allow part of the steam expansion (the other part being on the moving blades mounted on the rotor) The 4 impulse type 1500 MW nuclear steam turbines, from the EDF N4 program,were commissioned in 1996 on the CHOOZ and then CIVAUX plants.The diaphragms, located in the HP(high pressure) part of these turbines, have shown signs of failures very soon, due to a cracking of assembly welds,which is dangerous for the machines integrity. These failures questioned a construction mode which had been highly experienced previously. A large campaign of inspections and tests was carried out to feature the ways of failure,on site or in the factory during manufacturing.Site measurements combined with numerical simulations allowed to define excitations, harmful to these components,during operation. Temporary solutions were applied in order to allow immediate restart of the plants.In parallel,a modification of the diaphragms design and assembly method was studied and applied to withstand the various operating stresses. (author)

  12. 1.8 K Refrigeration Units for the LHC: Performance Assessment of Pre-series Units

    CERN Document Server

    Claudet, S; Millet, F; Tavian, L; 20th International Cryogenic Engineering Conference (ICEC20)

    2005-01-01

    The cooling capacity below 2 K for the superconducting magnets of the Large Hadron Collider (LHC), at CERN, will be provided by eight refrigeration units of 2400 W at 1.8 K, each of them coupled to a 4.5 K refrigerator. The two selected vendors have proposed cycles based on centrifugal cold compressors combined with volumetric screw compressors with sub-atmospheric suction, as previously identified by CERN as “reference cycle”. The supply of the series units was linked to successful testing and acceptance of the pre-series temporarily installed in a dedicated test station. The global capacity, the performance of cold compressors and some process specificities have been thoroughly tested and will be presented.

  13. Technical evaluation of the susceptibility of safety-related systems to flooding caused by the failure of non-category 1 systems for the San Onofre Nuclear Power Plant, Unit 1

    International Nuclear Information System (INIS)

    Latorre, V.R.; Victor, R.A.

    1980-11-01

    This report documents the technical evaluation of Southern California Edison Company's San Onofre Nuclear Power Plant, Unit 1, to determine whether the failure of any non-Category 1 (seismic) equipment could result in a condition, such as flooding, that might potentially adversely affect the performance of safety-related equipment required for the safe shutdown of the facility or to mitigate the consequences of an accident. Criteria developed by the US Nuclear Regulatory Commission were used to evaluate the acceptability of the existing protection as well as measures taken by Southern California Edison Company to minimize the danger of flooding and to protect safety-related equipment

  14. Predicting off-design range and performance of refrigeration cycle with two-stage centrifugal compressor and flash intercooler

    Energy Technology Data Exchange (ETDEWEB)

    Turunen-Saaresti, Teemu; Roeyttae, Pekka; Honkatukia, Juha; Backman, Jari [Lappeenranta University of Technology, Institute of Energy Technology, Laboratory of Fluid Dynamics, P.O. Box 20, 53851 Lappeenranta (Finland)

    2010-09-15

    A modern refrigeration process requires constant control to provide required cooling for the user. To properly and economically accommodate this need, a wide operation range of the compressor is necessary. Therefore, it is of interest to investigate the off-design operation of a cooling cycle and compressor. The refrigeration cycle equipped with a two-stage centrifugal compressor and a flash intercooler is studied. The compressor operation maps are generated with two different design codes and the operation values of the compressors are interpolated from the compressor maps in the simulation of the entire cooling cycle. Based on the previous studies of the utilised refrigeration cycle, R245fa is selected as coolant. The aim of this study is to demonstrate the control capacity of the centrifugal compressor and the performance of the cooling loop in off-design conditions. This configuration provides better and wider control over the cooling range than the traditional on-off control of displacement compressors. (author)

  15. The performance test of a modified miniature rotary compressor in upright and inverted modes subjected to microgravity

    International Nuclear Information System (INIS)

    Ma, Rui; Wu, Yu-ting; Du, Chun-xu; Chen, Xia; Zhang, De-lou; Ma, Chong-fang

    2016-01-01

    Highlights: • A miniature rotary compressor by ASPEN company was modified. • The modified compressor can be employed in microgravity. • Performance of upright compressor is superior to inverted mode in most cases. • Performance curves of system with inverted compressor are obtained. • Experimental results of compressor inverted and upright are compared. - Abstract: Vapor compression heat pump is a new concept of thermal control system and refrigerator for future space use. Compressor is a key component in the vapor compression heat pump. Development of compressor capable of operating in both microgravity (10 E-6 g) and lunar (1/6 g) environments is urgently needed for space thermal control systems based on heat pump technique. In this paper, a miniature rotary compressor by ASPEN company was modified to realize acceptable compressor lubrication and oil circulation in microgravity environments. An experimental system was built up to check the performance of the modified compressor subjected to microgravity. A performances comparison of inverted compressor with upright one was made. The influences of operating parameters such as refrigerant charge, cooling water temperature as well as compressor speed on the performances of vapor compression heat pump were investigated. The results show that the modified miniature rotary compressor in inverted mode can operate stably in a long period, which indicates that the modified compressor can be employed in microgravity environments. Compressor discharge temperature increased or decreased while COP changed more obviously with cooling water temperature and speed in microgravity. In most cases, performance of the upright compressor is superior to that of the inverted one. But when the compressor speed is from 1500 rpm to 2500 rpm or the coolant temperature is between 20 and 25 degrees, the performance of inverted compressor is better. The highest discharge temperature of the inverted compressor can be as high

  16. A numerical strategy for modelling rotating stall in core compressors

    Science.gov (United States)

    Vahdati, M.

    2007-03-01

    The paper will focus on one specific core-compressor instability, rotating stall, because of the pressing industrial need to improve current design methods. The determination of the blade response during rotating stall is a difficult problem for which there is no reliable procedure. During rotating stall, the blades encounter the stall cells and the excitation depends on the number, size, exact shape and rotational speed of these cells. The long-term aim is to minimize the forced response due to rotating stall excitation by avoiding potential matches between the vibration modes and the rotating stall pattern characteristics. Accurate numerical simulations of core-compressor rotating stall phenomena require the modelling of a large number of bladerows using grids containing several tens of millions of points. The time-accurate unsteady-flow computations may need to be run for several engine revolutions for rotating stall to get initiated and many more before it is fully developed. The difficulty in rotating stall initiation arises from a lack of representation of the triggering disturbances which are inherently present in aeroengines. Since the numerical model represents a symmetric assembly, the only random mechanism for rotating stall initiation is provided by numerical round-off errors. In this work, rotating stall is initiated by introducing a small amount of geometric mistuning to the rotor blades. Another major obstacle in modelling flows near stall is the specification of appropriate upstream and downstream boundary conditions. Obtaining reliable boundary conditions for such flows can be very difficult. In the present study, the low-pressure compression (LPC) domain is placed upstream of the core compressor. With such an approach, only far field atmospheric boundary conditions are specified which are obtained from aircraft speed and altitude. A chocked variable-area nozzle, placed after the last compressor bladerow in the model, is used to impose boundary

  17. Impact of few failure data on the opportunistic replacement policy for multi-component systems

    International Nuclear Information System (INIS)

    Laggoune, Radouane; Chateauneuf, Alaa; Aissani, Djamil

    2010-01-01

    In continuous operating units, the production loss is often very large during the system shut down. Their economic profitability is conditioned by the implementation of suitable maintenance policy that could increase the availability and reduce the operating costs. In this paper, an opportunistic replacement policy is proposed for multi-component series system in the context of data uncertainty, where the expected total cost per unit time is minimized under general lifetime distribution. When the system is down, either correctively or preventively, the opportunity to replace preventively non-failed components is considered. To deal with the problem of the small size of failure data samples, the Bootstrap technique is applied, in order to model the uncertainties in parameter estimates. The Weibull parameters are considered as random variables rather than just deterministic point estimates. A solution procedure based on Monte Carlo simulations with informative search method is proposed and applied to the optimization of preventive maintenance plan for a hydrogen compressor in an oil refinery.

  18. Design of compressors for FEL pulses using deformable gratings

    Science.gov (United States)

    Bonora, Stefano; Fabris, Nicola; Frassetto, Fabio; Giovine, Ennio; Miotti, Paolo; Quintavalla, Martino; Poletto, Luca

    2017-06-01

    We present the optical layout of soft X-rays compressors using reflective grating specifically designed to give both positive or negative group-delay dispersion (GDD). They are tailored for chirped-pulse-amplification experiments with FEL sources. The optical design originates from an existing compressor with plane gratings already realized and tested at FERMI, that has been demonstrated capable to introduce tunable negative GDD. Here, we discuss two novel designs for compressors using deformable gratings capable to give both negative and positive GDD. Two novel designs are discussed: 1) a design with two deformable gratings and an intermediate focus between the twos, that is demonstrated capable to introduce positive GDD; 2) a design with one deformable grating giving an intermediate focus, followed by a concave mirror and a plane grating, that is capable to give both positive and negative GDD depending on the distance between the second mirror and the second grating. Both the designs are tunable in wavelength and GDD, by acting on the deformable gratings, that are rotated to tune the wavelength and the GDD and deformed to introduce the radius required to keep the spectral focus. The deformable gratings have a laminar profile and are ruled on a thin silicon plane substrate. A piezoelectric actuator is glued on the back of the substrate and is actuated to give a radius of curvature that is varying from infinite (plane) to few meters. The ruling procedure, the piezoelectric actuator and the efficiency measurements in the soft X-rays will be presented. Some test cases are discussed for wavelengths shorter than 12 nm.

  19. The Application of the Probabilistic Collocation Method to a Transonic Axial Flow Compressor

    NARCIS (Netherlands)

    Loeven, G.J.A.; Bijl, H.

    2010-01-01

    In this paper the Probabilistic Collocation method is used for uncertainty quantification of operational uncertainties in a transonic axial flow compressor (i.e. NASA Rotor 37). Compressor rotors are components of a gas turbine that are highly sensitive to operational and geometrical uncertainties.

  20. Extensive optimisation analyses of the piping of two large underground gas storage ariel compressors

    NARCIS (Netherlands)

    Eijk, A.; Korst, H.J.C.; Ploumen, G.; Heyer, D.

    2007-01-01

    Two large identical 6-cylinder Ariel JGB/6 compressors of each 7.5 Mw, are used for the underground gas storage (UGS) plant of Essent in Epe, Germany. The compressors can be operated at a wide range of operating conditions, e.g. variable suction and discharge pressures, 2-stage mode during gas