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Sample records for shell-and-tube heat exchanger

  1. PENGARUH PENGGUNAAN BAFFLE PADA SHELL-AND-TUBE HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    Ekadewi Anggraini Handoyo

    2001-01-01

    Full Text Available Shell-and-tube heat exchanger is a device commonly used to transfer heat. To enhance the heat transfer occurred and to support the tubes inside the shell, baffles are installed. Better heat transfer is obviously expected in a heat exchanger. A research is done to find out the effect of baffle used toward the effectiveness and pressure drop in heat exchanger. The result is that the effectiveness increases when the baffles are installed. Effectiveness increases as the spacing between the baffles is smaller until certain spacing, and then it decreases. Abstract in Bahasa Indonesia : Shell-and-tube heat exchanger merupakan jenis alat penukar panas yang banyak digunakan. Untuk membuat perpindahan panas lebih baik dan untuk menyangga tube yang ada di dalam shell, maka sering dipasang baffle. Perpindahan panas yang lebih baik sangat diharapkan dalam suatu heat exchanger. Penelitian dilakukan untuk mengetahui pengaruh penggunaan baffle terhadap efektifitas dan penurunan tekanan dalam heat exchanger. Dari hasil penelitian didapat bahwa efektifitas meningkat dengan dipasangnya baffle. Efektifitas meningkat seiring dengan mengecilnya jarak antar baffle hingga suatu jarak tertentu, kemudian menurun. Kata kunci: penukar kalor, baffle, efektifitas.

  2. Effect of segmental baffles on the shell-and-tube heat exchanger effectiveness

    OpenAIRE

    Vuki? Mi?a V.; Tomi? Mladen A.; Živkovi? Predrag M.; Ili? Gradimir S.

    2014-01-01

    In this paper, the results of the experimental investigations of fluid flow and heat transfer in laboratory experimental shell-and-tube heat exchanger are presented. Shell-and-tube heat exchanger is with one pass of warm water on the shell side and two passes of cool water in tube bundle. Shell-and-tube heat exchanger is with 24x2 tubes (U-tube) in triangle layout. During each experimental run, the pressure drops and the fluid temperatures on shell side, al...

  3. Design and economic optimization of shell and tube heat exchangers using Artificial Bee Colony (ABC) algorithm

    International Nuclear Information System (INIS)

    Highlights: ? Artificial Bee Colony for shell and tube heat exchanger optimization is used. ? The total cost is minimized by varying design variables. ? This new approach can be applied for optimization of heat exchangers. - Abstract: In this study, a new shell and tube heat exchanger optimization design approach is developed. Artificial Bee Colony (ABC) has been applied to minimize the total cost of the equipment including capital investment and the sum of discounted annual energy expenditures related to pumping of shell and tube heat exchanger by varying various design variables such as tube length, tube outer diameter, pitch size, baffle spacing, etc. Finally, the results are compared to those obtained by literature approaches. The obtained results indicate that Artificial Bee Colony (ABC) algorithm can be successfully applied for optimal design of shell and tube heat exchangers.

  4. A SIMPLIFIED PREDICTIVE CONTROL FOR A SHELL AND TUBE HEAT EXCHANGER

    OpenAIRE

    S.RAJASEKARAN,; Dr.T.KANNADASAN

    2010-01-01

    In this paper a simplified predictive control design is applied for the controlling a temperature of a fluid stream using the shell and tube heat exchanger. The predictive control design based on Dynamic Matrix Control (DMC) involves the complicated inversion computation for higher dimensional matrix. Using DMC for controlling a temperature of the shell and tube heat exchanger, there is still a need for optimization of conversation of energy. The simplified predictive control is based on DMC,...

  5. Simulasi Performansi Heat Exchanger Type Shell And Tube Dengan Double Segmental Baffle Terhadap Helical Baffle

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    Anggareza Adhitiya

    2013-12-01

    Full Text Available Pada heat exchanger type shell and tube, selain pengunaan baffle yang bertujuan untuk mengarahkan aliran pada sisi shell juga bertujuan untuk meningkatkan laju perpindahan panas yang terjadi antara fluida kerja dengan cara menimbulkan olakan aliran di sisi shell. Olakan –olakan ini nantinya yang akan mempengaruhi besarnya perpindahan panas dalam sisi shell. Pada kondisi standart baffle yang digunakan pada tugas akhir ini adalah jenis double segmental. Double segmental baffle mempunyai tingkat pressure drop yang cukup besar. sehingga perlu di ganti dengan baffle jenis helical yang mempunyai pressure drop yang lebih kecil. Untuk mengetahui performansi heat exchanger maka perlu adanya penelitian lebih lanjut simulasi numerik pada baffle heat exchanger type shell and tube. agar didapat pengaruh jenis baffle yang di gunakan terhadap karakteristik aliran dan perpindahan panas dari suatu heat exchanger type shell and tube. Tugas Akhir ini menggunakan program GAMBIT 2.4.6 untuk penggambaran geometri secara tiga dimensi dan program FLUENT 6.3.26 untuk mensimulasi aliran yang terjadi di dalam shell and tube heat exchanger. Pada software FLUENT 6.3.26 digunakan permodelan 3D Steady Flow dengan  memilih k – Epsilon RNG sebagai turbulence modeling serta mengaktifkan persamaan energy. Penelitian dilakukan dengan menggunakan dua variasi heat exchanger dengan jenis baffle yang berbeda .Heat exchanger type shell and tube dengan jenis double segmental baffle mempunyai nilai koefisien konveksi rata-rata = 218.408 w/m2.K. Sedangkan untuk helical baffle sebesar = 171.122 w/m2.K. Temperature outflow pada heat exchanger type shell and tube dengan jenis double segmental baffle = 306.7450K. Di ikuti dengan pressure drop sebesar = 2100 pascal Sedangkan untuk helical baffle mempunyai temperatur outflow sebesar = 307.0220K dengan pressure drop sebesar = 500 pascal.

  6. Thermoeconomic optimization of baffle spacing for shell and tube heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Eryener, Dogan [Department of Mechanical Engineering, Trakya University, Muh. Mim. Fak., 22030 Edirne (Turkey)

    2006-07-15

    Despite the importance of thermoeconomic analysis in shell and tube heat exchanger design, the determination of the optimum baffle spacing by using the thermoeconomic analysis is usually neglected. On the other hand, baffle spacing is one of the most important parameters used in the design of shell and tube heat exchangers, and there is no precise criterion for the determination of baffle spacing in the literature. In this study, thermoeconomic analysis is used to determine the optimum baffle spacing, accompanied by an example of such an optimization of baffle spacing for a shell and tube heat exchanger. The results of this example are then used to demonstrate how the optimum ratio of baffle spacing to shell diameter is determined precisely and affected by the varying values of the geometrical parameters. Finally, the results are compared to those obtained by classical approaches. (author)

  7. A SIMPLIFIED PREDICTIVE CONTROL FOR A SHELL AND TUBE HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    S.RAJASEKARAN,

    2010-12-01

    Full Text Available In this paper a simplified predictive control design is applied for the controlling a temperature of a fluid stream using the shell and tube heat exchanger. The predictive control design based on Dynamic Matrix Control (DMC involves the complicated inversion computation for higher dimensional matrix. Using DMC for controlling a temperature of the shell and tube heat exchanger, there is still a need for optimization of conversation of energy. The simplified predictive control is based on DMC, which reduces the computational complexity by exploring its internal mechanism. Finally the simplified Predictive Control is applied to shell and tube heat exchanger and the results of this control algorithm compared with the conventional PID controller and DMC based PID Controllers.

  8. Comprehensive approach to avoid vibration and fretting in shell-and-tube heat exchangers

    International Nuclear Information System (INIS)

    This paper outlines a comprehensive approach to avoid vibration and fretting-wear problems in shell-and-tube heat exchangers. The approach consists of: avoiding large vibration amplitudes due to excitation mechanisms such as fluid-elastic instability and periodic wake shedding resonace while making sure that low amplitude vibrations due to other sources do not cause excessive tube damage. 15 refs

  9. Flow induced vibration in shell and tube heat exchangers

    International Nuclear Information System (INIS)

    Assessing heat exchanger designs, from the standpoint of flow induced vibration, is becoming increasingly important as shell side flow velocities are increased in a quest for better thermal performance. This paper reviews the state of the art concerning the main sources of vibration excitation, i.e. vortex shedding resonance, turbulent buffeting, fluidelastic instability and acoustic resonance, as well as the structural dynamics of the tubes. It is concluded that there are many areas which require further investigation but there are sufficient data available at present to design, with reasonable confidence, units that will be free from flow induced vibration. Topics which are considered to be key areas for further work are listed

  10. On the optimal design of shell and tube heat exchanger for nuclear applications

    International Nuclear Information System (INIS)

    In nuclear industry, heat exchanger plays an important role in the transfer of heat from reactor core, where heat is generated, to the ultimate heat sink UHS, and then is dissipated. The actual design of heat exchanger not only relies on thermohydraulic considerations but also on economical aspects and radiological safety considerations. For optimal design of heat exchanger for a specific application a compromise should be made for determining the important factors affecting the design. In this paper, an optimization model is presented for shell and tube heat exchanger, which could be considered as a tool for computer aided design. A case study is presented to explore the present adopted model. 3 figs

  11. Design of portable shell and tube heat exchanger for a solar powered water distiller

    International Nuclear Information System (INIS)

    Full text: This study presents theoretical considerations and results of a portable shell and tube heat exchanger in a solar water distiller system. The device is composed of glass heat exchanger which served as a condenser for vapor condensing which were produced in black paint solar absorber. It is also composed of a tank for salt water source and a tank for produced distilled water. Shell and tube was designed and simulated using an implicit numerical scheme. Simulation results showed that accumulated mass water greatly depended on the inlet vapor temperature and volume, heat exchanger material, coolant water temperature and volume. Thus, changing the material from stainless steel to glass in the same condition (vapor temperature, vapor volume, coolant temperature and coolant volume); results comes to an acceptable range. These inexpensive shell and tube heat exchangers with 500 mm length, 19 mm Tube diameter, 100 mm and 200 mm Shell diameters respectively for stainless steel and Pyrex Glass permitted to produce 40 Liter/ day distilled water from vapor with 378 K inlet temperature in atmosphere pressure. If inlet pressure increases, vapor temperature will decline and thereupon, heat exchanger efficiency tangibility will increase. (author)

  12. Performance Analysis of Shell and Tube Heat Exchanger Using Miscible System

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    M. Thirumarimurugan

    2008-01-01

    Full Text Available An experimental investigation on comparative heat transfer study on a solvent and solution were made using 1-1 Shell and Tube Heat Exchanger. Steam is the hot fluid, whereas Water and Acetic acid-Water miscible solution serves as cold fluid. A series of runs were made between steam and water, steam and Acetic acid solution. In addition to, the volume fraction of Acetic acid was varied and the experiment was held. The flow rate of the cold fluid is maintained from 120 to 720 lph and the volume fraction of Acetic acid is varied from 10-50%. Experimental results such as exchanger effectiveness, overall heat transfer coefficients were calculated. A mathematical model was developed for the outlet temperatures of both the Shell and Tube side fluids and was simulated using MATLAB program. The model was compared with the experimental findings and found to be valid.

  13. Thermal effectiveness of multiple shell and tube pass TEMA E heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Pignotti, A. (TECHNIT S.A., Buenos Aires (Argentina)); Tamborenea, P.I. (Fundacion Hermanos, Buenos Aires (Argentina))

    1988-02-01

    The thermal effectiveness of a TEMAE shell-and-tube heat exchanger, with one shell pass and an arbitrary number of tube passes, is determined under the usual simplifying assumptions of perfect transverse mixing of the shell fluid, no phase change, and temperature independence of the heat capacity rates and the heat transfer coefficient. A purely algebraic solution is obtained for the effectiveness as a functions of the heat capacity rate ratio and the number of heat transfer units. The case with M shell passes and N tube passes is easily expressed in terms of the single-shell-pass case.

  14. Shell side CFD analysis of a small shell-and-tube heat exchanger

    International Nuclear Information System (INIS)

    The shell side design of a shell-and-tube heat exchanger; in particular the baffle spacing, baffle cut and shell diameter dependencies of the heat transfer coefficient and the pressure drop are investigated by numerically modeling a small heat exchanger. The flow and temperature fields inside the shell are resolved using a commercial CFD package. A set of CFD simulations is performed for a single shell and single tube pass heat exchanger with a variable number of baffles and turbulent flow. The results are observed to be sensitive to the turbulence model selection. The best turbulence model among the ones considered is determined by comparing the CFD results of heat transfer coefficient, outlet temperature and pressure drop with the Bell-Delaware method results. For two baffle cut values, the effect of the baffle spacing to shell diameter ratio on the heat exchanger performance is investigated by varying flow rate.

  15. Velocity profiles between two baffles in a shell and tube heat exchanger

    Science.gov (United States)

    Chang, Tae-Hyun; Lee, Chang-Hoan; Lee, Hae-Soo; Lee, Kwon-Soo

    2015-06-01

    Heat exchangers are extensively utilized for waste heat recovery, oil refining, chemical processing, and steam generation. In this study, velocity profiles are measured using a 3D particle image velocimetry (PIV) system betweentwo baffles in a shell and tube heat exchanger for parallel and counter flows. The PIV and computational fluid dynamics results show the occurrence of some strong vectors near the bottom. These vectors are assumed due to the clearance between the inner tubes and the front baffle. Therefore, the major parts of the vectors are moved out through the bottom opening of the rear baffle, and other vectors produce a large circle between the two baffles. Numerical simulations are conducted to investigate the effects of the baffle on the heat exchanger using the Fluent software. The k-? turbulence model is employed to calculate the flows along the heat exchanger

  16. Development of a control system for shell and tube heat exchanger in Matlab simulink

    International Nuclear Information System (INIS)

    The main objective of this research is to develop a control system for heat exchanger so that the desired outlet temperature can be achieved by controlling the flow rate. For this purpose, shell and tube heat exchanger was chosen and modeled it by using its mathematical equations in MATLAB (Matrix Laboratory) Simulink and calculated the outlet temperature by NTU (Number of Transfer Units) effectiveness method. For the purpose of Control system, MPC (Model Predictive Controller) was used. This research will open a new way of Modeling Equations instead of transfer functions in MATLAB (Matrix Laboratory) Simulink. Using the model, it was developed; with controller, so as to manipulate the output temperature by simply controlling the flow rate. It can be justified weather the design of a new heat exchanger would be feasible or not for the specific requirements. At last this research is very helpful in Industries for the purpose of designing, development and control of new Heat Exchangers. (author)

  17. PARAMETER IDENTIFICATION AND CONTROL OF A SHELL AND TUBE HEAT EXCHANGER

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    Arun Sivaram

    2013-04-01

    Full Text Available In this work, we discuss about the process parameter identification and control of a Counter Flow Shell and Tube Heat Exchanger using Recursive Least Square Algorithm(RLS and Self Turning controller respectively. Here, we model the process with the help of experimental data using RLS Algorithm. Then an ST controller which comes under adaptive controller is used to control the process.With the help of STC, the tube outlet temperature is controlled by adjusting the flow of cold fluid through the shell side. In conventional way a PID controller is also tuned, and the performance is compared with STC using MATLAB simulations.

  18. Designing shell-and-tube heat exchangers with velocity dependent fouling

    Energy Technology Data Exchange (ETDEWEB)

    Butterworth, D. [AEA Technology Engineering Software, Abingdon, Oxon (United Kingdom)

    2000-08-01

    This paper uses the 'design-envelope' concept to explore the effect of velocity dependent fouling on the design of a shell-and-tube exchanger. A number of tube side fouling scenarios are explored including constant fouling, a step change in fouling at a critical velocity and a continuous variation in fouling with velocity. It is shown that the inclusion of the velocity dependence has a profound effect on the final design result and therefore on the design strategy. The effect of fouling both on heat transfer and pressure drop is considered. Cases are illustrated where there are two separate design envelopes, one for the fouled exchanger and one for the clean exchanger. Conclusions are drawn about the implications which this has on the specification, design and operation of exchangers. (au)

  19. Performance evaluation of a shell and tube heat exchanger operated with oxide based nanofluids

    Science.gov (United States)

    Shahrul, I. M.; Mahbubul, I. M.; Saidur, R.; Khaleduzzaman, S. S.; Sabri, M. F. M.

    2015-08-01

    This study is about the performance evaluation of a shell and tube heat exchanger operated with nanofluid. Thermal conductivity, viscosity, and density of the nanofluids were increased, but the specific heat of the nanofluids was decreased with increasing the concentrations of the particles. The convective heat transfer coefficient was found to be 2-15 % higher than that of water at 50 kg/min of both side fluid. Nevertheless, energy effectiveness has improved about 23-52 % for the above-mentioned nanofluids. As, energy effectiveness (?) is strongly depends on the density and specific heat of the operating fluids therefore, maximum ? has obtained for ZnO-W nanofluid and lowest found for SiO2-W nanofluid.

  20. CACHE: an extended BASIC program which computes the performance of shell and tube heat exchangers

    International Nuclear Information System (INIS)

    An extended BASIC program, CACHE, has been written to calculate steady state heat exchange rates in the core auxiliary heat exchangers, (CAHE), designed to remove afterheat from High-Temperature Gas-Cooled Reactors (HTGR). Computationally, these are unbaffled counterflow shell and tube heat exchangers. The computational method is straightforward. The exchanger is subdivided into a user-selected number of lengthwise segments; heat exchange in each segment is calculated in sequence and summed. The program takes the temperature dependencies of all thermal conductivities, viscosities and heat capacities into account providing these are expressed algebraically. CACHE is easily adapted to compute steady state heat exchange rates in any unbaffled counterflow exchanger. As now used, CACHE calculates heat removal by liquid weight from high-temperature helium and helium mixed with nitrogen, oxygen and carbon monoxide. A second program, FULTN, is described. FULTN computes the geometrical parameters required as input to CACHE. As reported herein, FULTN computes the internal dimensions of the Fulton Station CAHE. The two programs are chained to operate as one. Complete user information is supplied. The basic equations, variable lists, annotated program lists, and sample outputs with explanatory notes are included

  1. Numerical investigation on a novel shell-and-tube heat exchanger with plate baffles and experimental validation

    International Nuclear Information System (INIS)

    Highlights: • A novel shell-and-tube heat exchanger with plate baffles is proposed. • Heat transfer and pressure drop of computational calculations are studied. • Experimental method is carried out to verify the modeling approach. • Path lines, temperature field and pressure field are analyzed. - Abstract: A novel shell-and-tube heat exchanger with new plate baffles is proposed. It is numerically investigated in comparison with a shell-and-tube heat exchanger with rod baffles. Commercial softwares FLUENT 6.3 and GAMBIT 2.3 are adopted for modeling and computational calculations. The modeling approach is verified with experimental approach. The shell-side results of heat transfer, flow performance, and comprehensive performance are analyzed. The Nusselt number for the plate baffles heat exchanger is around 128–139% of that for the rod baffles heat exchanger. The pressure drop for the novel one is about 139–147% of that for the rod baffles heat exchanger. Overall, the novel plate baffles heat exchanger illustrates evidently higher comprehensive performance (115–122%) than the rod baffles one. The temperature field, pressure field, and path lines are analyzed to demonstrate the advantage of the novel shell-and-tube heat exchanger

  2. Effect of Segmental Baffles at Different Orientation on the Performances of Single Pass Shell and Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Neeraj kumar

    2014-09-01

    Full Text Available In present work, experimentation of single pass, counter flow shell and tube heat exchanger containing segmental baffles at different orientations has been conducted to calculate some parameters (heat transfer rate and pressure drop at different Reynolds number in laminar flow. In the present work, an attempt has been made to study the effect of increase in Reynolds number at different angular orientation “?” of the baffles. The range of “?” vary from 0° to 45° (i.e 0°, 15°, 30° and 45° and Reynolds number ranges from 500 to 2000 (i.e 500, 1000, 1500 and 2000. A prototype model of shell and tube type heat exchanger has been fabricated to carry out the experiments. The experiments were performed to determine the effect of baffle orientation on the performance of shell and tube heat exchanger. Water is taken as the working fluid used in both shell and tubes. The objective of the present work is to predict the variation of heat transfer rate, LMTD, heat transfer coefficient, and pressure drop to the shell side with change in range of Reynolds number at different baffle orientations. Based on the experimental result it has been observed that the angular orientation of baffles and the Reynolds number effects the heat transfer rate and pressure drop in the shell and tube heat exchanger. The heat transfer rate increases up to 30° angular orientation of the baffles and after that there is a drop in heat transfer rate at ? = 45°. The pressure drop to the shell sides decreases continuously from 0° to 45° which helps in reducing the pumping cost of the shell and tube heat exchanger.

  3. Comparison of shell-and-tube with plate heat exchangers for the use in low-temperature organic Rankine cycles

    International Nuclear Information System (INIS)

    Highlights: • Binary cycles for low-temperature heat sources are investigated. • Shell-and-tube and plate heat exchangers are modeled. • System optimization of the cycle variables and heat exchanger geometry. • ORCs with plate heat exchangers obtain in most cases higher efficiencies. - Abstract: Organic Rankine cycles (ORCs) can be used for electricity production from low-temperature heat sources. These ORCs are often designed based on experience, but this experience will not always lead to the most optimal configuration. The ultimate goal is to design ORCs by performing a system optimization. In such an optimization, the configuration of the components and the cycle parameters (temperatures, pressures, mass flow rate) are optimized together to obtain the optimal configuration of power plant and components. In this paper, the configuration of plate heat exchangers or shell-and-tube heat exchangers is optimized together with the cycle configuration. In this way every heat exchanger has the optimum allocation of heat exchanger surface, pressure drop and pinch-point-temperature difference for the given boundary conditions. ORCs with plate heat exchangers perform mostly better than ORCs with shell-and-tube heat exchangers, but one disadvantage of plate heat exchangers is that the geometry of both sides is the same, which can result in an inefficient heat exchanger. It is also shown that especially the cooling-fluid inlet temperature and mass flow have a strong influence on the performance of the power plant

  4. Experimental performance investigation of a shell and tube heat exchanger by exergy based sensitivity analysis

    Science.gov (United States)

    Mert, Suha Orçun; Reis, Alper

    2015-07-01

    Heat exchangers are used extensively in many industrial branches, primarily so in chemical and energy sectors. They also have important household usage as they are used in central and local heating systems. Any betterment on heat exchangers will serve greatly in preserving our already dwindling and costly energy resources. Strong approach of exergy analysis -which helps find out where the first steps should be taken in determining sources of inefficiencies and how to remedy them- will be used as a means to this end. The maximum useful work that can be harnessed from systems relationships with its environment is defined as exergy. In this study, the inlet and outlet flow rate values of fluids and temperature of hot stream both on shell and tube parts of a shell-tube heat exchange system have been inspected and their effects on the exergy efficiency of this thermal system have been analyzed. It is seen that the combination of high tube side inlet temperature, low shell side flow rate and high tube side flow rate are found to be the optimum for this experimental system with reaching 75, 65, and 32 % efficiencies respectively. Selecting operating conditions suitable to this behavior will help to increase the overall efficiency of shell-tube heat exchange systems and cause an increment in energy conservation.

  5. CFD Analysis of Shell and Tube Heat Exchanger to Study the Effect of Baffle Cut on the Pressure Drop

    OpenAIRE

    Avinash D Jadhav; Tushar A Koli

    2014-01-01

    The shell side design of a shell and tube heat exchanger; in particular the baffle spacing, baffle cut and shell diameter dependencies of the heat transfer coefficient and the pressure drop are investigated by numerically modelling a small heat exchanger. The flow and temperature fields inside the shell are resolved using a commercial CFD package. A set of CFD simulations is performed for a single shell and single tube pass heat exchanger with a variable number of baffles and turb...

  6. Optimum configuration of shell-and-tube heat exchangers for the use in low-temperature organic Rankine cycles

    OpenAIRE

    Walraven, Daniël; Laenen, Ben; D'haeseleer, William

    2014-01-01

    In this paper, a first step towards a system optimization of organic Rankine cycles (ORCs) is taken by optimizing the cycle parameters together with the configuration of shell-and-tube heat exchangers. In this way every heat exchanger has the optimum allocation of heat-exchanger surface, pressure drop and pinch-point-temperature difference for the given boundary conditions. Different tube configurations are investigated in this paper. It is concluded that the 30°-tube configurations should be...

  7. Optimum configuration of shell-and-tube heat exchangers for the use in low-temperature organic Rankine cycles

    International Nuclear Information System (INIS)

    Highlights: • Binary cycles for low-temperature heat sources are investigated. • Shell-and-tube heat exchangers are modeled. • System optimization of the cycle variables and shell-and-tube geometry. • 30°-tube configuration is optimal for single-phase heat exchangers. • 60°-tube configuration is optimal for two-phase heat exchangers. - Abstract: In this paper, a first step towards a system optimization of organic Rankine cycles (ORCs) is taken by optimizing the cycle parameters together with the configuration of shell-and-tube heat exchangers. In this way every heat exchanger has the optimum allocation of heat-exchanger surface, pressure drop and pinch-point-temperature difference for the given boundary conditions. Different tube configurations are investigated in this paper. It is concluded that the 30°-tube configurations should be used for the single-phase heat exchangers and the 60°-tube configuration for the two-phase heat exchangers. The performance of subcritical cycles can be strongly improved by adding a second pressure level. Recuperated cycles are only useful when the temperature of the heat source after the ORC should be relatively high

  8. Estimated Outlet Temperatures in Shell-and-Tube Heat Exchanger Using Artificial Neural Network Approach Based on Practical Data

    OpenAIRE

    Hisham Hassan Jasim

    2013-01-01

    The objective of this study is to apply Artificial Neural Network for heat transfer analysis of shell-and-tube heat exchangers widely used in power plants and refineries. Practical data was obtained by using industrial heat exchanger operating in power generation department of Dura refinery. The commonly used Back Propagation (BP) algorithm was used to train and test networks by divided the data to three samples (training, validation and testing data) to give more approach data with actual ca...

  9. Experimental Study on Heat Transfer Characteristics of Shell and Tube Heat Exchanger Using Hitran Wire Matrix Turbulators As Tube Inserts.

    Directory of Open Access Journals (Sweden)

    Manoj

    2014-06-01

    Full Text Available Shell and tube heat exchangers are extensively used in boilers, oil coolers, pre-heaters, condensers etc. They are also having special importance in process application as well as refrigeration and air conditioning industries. The present paper emphasizes on heat transfer characteristics of shell and tube heat exchangers with the aid of hiTRAN wire matrix inserts is been studied. Investigations were made on effect of mass flow rate of water on heat transfer characteristics in case of plain tube without inserts. When hiTRAN wire matrix tube inserts are used, which effectively increases the turbulence of tube side flow due to the hydrodynamic and thermal agitation of boundary layer in turns increases additional pressure drop is available in the system. This results in increase in the wall shear, reduced wall temperature which enhances substantial increase in tube side heat transfer characteristics. Heat and cooling processes streams is a standard operation in many industries this operation is often performed in heat exchangers where the heated or cold fluid flows under laminar conditions inside the tubes the mechanisms of under those flow conditions are complex poorly understood since they can involve both forced and natural convection making accurate prediction for heat exchanger. Heat transfer in laminar flow regimes is low by default but can be greatly increased by the use of passive heat transfer enhancement such as tube inserts. The present analysis the hiTRAN wire matrix turbulators were used and increased heat transfer characteristics as expected outcomes.

  10. Design of shell-and-tube heat exchangers when the fouling depends on local temperature and velocity

    Energy Technology Data Exchange (ETDEWEB)

    Butterworth, D. [HTFS, Hyprotech, Didcot (United Kingdom)

    2002-07-01

    Shell-and-tube heat exchangers are normally designed on the basis of a uniform and constant fouling resistance that is specified in advance by the exchanger user. The design process is then one of determining the best exchanger that will achieve the thermal duty within the specified pressure drop constraints. It has been shown in previous papers [Designing shell-and-tube heat exchangers with velocity-dependant fouling, 34th US national Heat Transfer Conference, 20-22 August 2000, Pittsburg, PA; Designing shell-and-tube heat exchangers with velocity-dependant fouling, 2nd Int. Conf. on Petroleum and Gas Phase Behavior and Fouling, 27-31 August 2000, Copenhagen] that this approach can be extended to the design of exchangers where the design fouling resistance depends on velocity. The current paper briefly reviews the main findings of the previous papers and goes on to treat the case where the fouling depends also on the local temperatures. The Ebert-Panchal [Analysis of Exxon crude-oil, slip-stream coking data, Engineering Foundation Conference on Fouling Mitigation of Heat Exchangers, 18-23 June 1995, California] form of fouling rate equation is used to evaluate this fouling dependence. When allowing for temperature effects, it becomes difficult to divorce the design from the way the exchanger will be operated up to the point when the design fouling is achieved. However, rational ways of separating the design from the operation are proposed. (author)

  11. Optimization of shell-and-tube heat exchangers conforming to TEMA standards with designs motivated by constructal theory

    International Nuclear Information System (INIS)

    Highlights: • A design method of heat exchangers motivated by constructal theory is proposed. • A genetic algorithm is applied and the TEMA standards are rigorously followed. • Three cases are studied to illustrate the advantage of the proposed design method. • The design method will reduce the total cost compared to two other methods. - Abstract: A modified optimization design approach motivated by constructal theory is proposed for shell-and-tube heat exchangers in the present paper. In this method, a shell-and-tube heat exchanger is divided into several in-series heat exchangers. The Tubular Exchanger Manufacturers Association (TEMA) standards are rigorously followed for all design parameters. The total cost of the whole shell-and-tube heat exchanger is set as the objective function, including the investment cost for initial manufacture and the operational cost involving the power consumption to overcome the frictional pressure loss. A genetic algorithm is applied to minimize the cost function by adjusting parameters such as the tube and shell diameters, tube length and tube arrangement. Three cases are studied which indicate that the modified design approach can significantly reduce the total cost compared to the original design method and traditional genetic algorithm design method

  12. Experimental Study of Inlet/Outlet Flow Characteristics in Tube-side of Shell and Tube Heat Exchanger

    International Nuclear Information System (INIS)

    The inlet/outlet flow in the tube-side of the shell and tube heat exchanger was experimentally measured to investigate the effect of the porous baffle on uniform flow distribution. A 1/3rd scale-downed model of a heat exchanger was used and particle image velocimetry was applied for measuring the instantaneous velocity vector fields. The absolute errors in the flow rate were calculated and compared for the tube-side with and without the porous baffle, by varying the flow rate from 60 to 90 LPM. The results revealed that the porous baffle can improve flow uniformity and reduce the absolute error in the flow rate of the model with the baffle by about 74%, compared to that without the baffle. This result can be used for improving the performance and design of the shell and tube heat exchanger

  13. Design optimization of shell-and-tube heat exchangers using single objective and multiobjective particle swarm optimization

    International Nuclear Information System (INIS)

    The Particle Swarm Optimization (PSO) algorithm is used to optimize the design of shell-and-tube heat exchangers and determine the optimal feasible solutions so as to eliminate trial-and-error during the design process. The design formulation takes into account the area and the total annual cost of heat exchangers as two objective functions together with operating as well as geometrical constraints. The Nonlinear Constrained Single Objective Particle Swarm Optimization (NCSOPSO) algorithm is used to minimize and find the optimal feasible solution for each of the nonlinear constrained objective functions alone, respectively. Then, a novel Nonlinear Constrained Mult-objective Particle Swarm Optimization (NCMOPSO) algorithm is used to minimize and find the Pareto optimal solutions for both of the nonlinear constrained objective functions together. The experimental results show that the two algorithms are very efficient, fast and can find the accurate optimal feasible solutions of the shell and tube heat exchangers design optimization problem. (orig.)

  14. Two-phase experimental heat transfer studies on a water-diesel system in a shell and tube heat exchanger

    OpenAIRE

    V. Alagesan; Sundaram, S

    2012-01-01

    Two-phase heat transfer involving two immiscible systems is gaining importance in petrochemical and allied industries. Varying compositions of diesel and water were experimentally studied in a 1:2 shell and tube heat exchanger. The data on pure water and diesel were fitted to an equation of the form. h1? = a NmRe.The two-phase multiplier, ? L, was related to the Lockhart Martinelli (L-M) parameter, ?tt², using the two-phase data and a correlation ? L = b+c(?tt²)+d/(&#...

  15. Shell side numerical analysis of a shell and tube heat exchanger considering the effects of baffle inclination angle on fluid flow using CFD

    OpenAIRE

    Raj Karuppa Thundil R.; Ganne Srikanth

    2012-01-01

    In this present study, attempts were made to investigate the impacts of various baffle inclination angles on fluid flow and the heat transfer characteristics of a shell-and-tube heat exchanger for three different baffle inclination angles namely 0°,10° and 20°. The simulation results for various shell and tube heat exchangers, one with segmental baffles perpendicular to fluid flow and two with segmental baffles inclined to the direction of fluid flow are compared for their performance. ...

  16. Validation of the method for determination of the thermal resistance of fouling in shell and tube heat exchangers

    International Nuclear Information System (INIS)

    Highlights: • Heat recovery in a heat exchanger network (HEN). • A novel method for on-line determination of the thermal resistance of fouling is presented. • Details are developed for shell and tube heat exchangers. • The method was validated and sensibility analysis was carried out. • Developed approach allows long-term monitoring of changes in the HEN efficiency. - Abstract: A novel method for on-line determination of the thermal resistance of fouling in shell and tube heat exchangers is presented. It can be applied under the condition that the data on pressure, temperature, mass flowrate and thermophysical properties of both heat-exchanging media are continuously available. The calculation algorithm for use in the novel method is robust and ensures reliable determination of the thermal resistance of fouling even if the operating parameters fluctuate. The method was validated using measurement data retrieved from the operation records of a heat exchanger network connected with a crude distillation unit rated 800 t/h. Sensibility analysis of the method was carried out and the calculated values of the thermal resistance of fouling were critically reviewed considering the results of qualitative evaluation of fouling layers in the exchangers inspected during plant overhaul

  17. Parametric study of gross flow maldistribution in a single-pass shell and tube heat exchanger in turbulent regime

    International Nuclear Information System (INIS)

    Highlights: • A potential means of reducing flow maldistribution in exchangers. • In turbulent flows, maldistribution is but only tube number. • A Gaussian function can also express flow maldistribution in the exchanger. -- Abstract: Uniform distribution of flow in tube bundle of shell and tube heat exchangers is an arbitrary assumption in conventional heat exchanger design. Nevertheless, in practice, flow maldistribution may be an inevitable occurrence which may have severe impacts on thermal and mechanical performance of heat exchangers i.e. fouling. The present models for flow maldistribution in the tube-side deal only with the maximum possible velocity deviation. Other flow maldistribution models propose and recommend the use of a probability distribution, e.g. Gaussian distribution. None of these, nevertheless, estimate quantitatively the number of tubes that suffer from flow maldistribution. This study presents a mathematical model for predicting gross flow maldistribution in the tube-side of a single-pass shell and tube heat exchanger. It can quantitatively estimate the magnitude of flow maldistribution and the number of tubes which have been affected. The validation of the resultant model has been confirmed when compared with similar study using computational fluid dynamics (CFD)

  18. CFD Analysis of Shell and Tube Heat Exchanger to Study the Effect of Baffle Cut on the Pressure Drop

    Directory of Open Access Journals (Sweden)

    Avinash D Jadhav

    2014-07-01

    Full Text Available The shell side design of a shell and tube heat exchanger; in particular the baffle spacing, baffle cut and shell diameter dependencies of the heat transfer coefficient and the pressure drop are investigated by numerically modelling a small heat exchanger. The flow and temperature fields inside the shell are resolved using a commercial CFD package. A set of CFD simulations is performed for a single shell and single tube pass heat exchanger with a variable number of baffles and turbulent flow. The results are observed to be sensitive to the turbulence model selection. The best turbulence model among the ones considered is determined by comparing the CFD results of heat transfer coefficient, outlet temperature and pressure drop with the Bell–Delaware method results. For two baffle cut values, the effect of the baffle spacing to shell diameter ratio on the heat exchanger performance is investigated by varying flow rate.

  19. Optimization of a Finned Shell and Tube Heat Exchanger Using a Multi-Objective Optimization Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Heidar Sadeghzadeh

    2015-08-01

    Full Text Available Heat transfer rate and cost significantly affect designs of shell and tube heat exchangers. From the viewpoint of engineering, an optimum design is obtained via maximum heat transfer rate and minimum cost. Here, an analysis of a radial, finned, shell and tube heat exchanger is carried out, considering nine design parameters: tube arrangement, tube diameter, tube pitch, tube length, number of tubes, fin height, fin thickness, baffle spacing ratio and number of fins per unit length of tube. The “Delaware modified” technique is used to determine heat transfer coefficients and the shell-side pressure drop. In this technique, the baffle cut is 20 percent and the baffle ratio limits range from 0.2 to 0.4. The optimization of the objective functions (maximum heat transfer rate and minimum total cost is performed using a non-dominated sorting genetic algorithm (NSGA-II, and compared against a one-objective algorithm, to find the best solutions. The results are depicted as a set of solutions on a Pareto front, and show that the heat transfer rate ranges from 3517 to 7075 kW. Also, the minimum and maximum objective functions are specified, allowing the designer to select the best points among these solutions based on requirements. Additionally, variations of shell-side pressure drop with total cost are depicted, and indicate that the pressure drop ranges from 3.8 to 46.7 kPa.

  20. Two-phase experimental heat transfer studies on a water-diesel system in a shell and tube heat exchanger

    Scientific Electronic Library Online (English)

    V., Alagesan; S., Sundaram.

    2012-06-01

    Full Text Available Two-phase heat transfer involving two immiscible systems is gaining importance in petrochemical and allied industries. Varying compositions of diesel and water were experimentally studied in a 1:2 shell and tube heat exchanger. The data on pure water and diesel were fitted to an equation of the form [...] . h1? = a NmRe.The two-phase multiplier, ? L, was related to the Lockhart Martinelli (L-M) parameter, ?tt², using the two-phase data and a correlation ? L = b+c(?tt²)+d/(?tt²)² was established. The two-phase heat transfer coefficient was calculated based on the coefficients 'a' and 'm' for pure diesel and pure water along with ?L and the L-M parameter. The calculated values of the two-phase heat transfer coefficient h2? based on pure diesel and pure water suggest that diesel is a better reference fluid since the average error is much smaller compared to pure water as reference.

  1. Two-phase experimental heat transfer studies on a water-diesel system in a shell and tube heat exchanger

    Directory of Open Access Journals (Sweden)

    V. Alagesan

    2012-06-01

    Full Text Available Two-phase heat transfer involving two immiscible systems is gaining importance in petrochemical and allied industries. Varying compositions of diesel and water were experimentally studied in a 1:2 shell and tube heat exchanger. The data on pure water and diesel were fitted to an equation of the form. h1? = a NmRe.The two-phase multiplier, ? L, was related to the Lockhart Martinelli (L-M parameter, ?tt², using the two-phase data and a correlation ? L = b+c(?tt²+d/(?tt²² was established. The two-phase heat transfer coefficient was calculated based on the coefficients 'a' and 'm' for pure diesel and pure water along with ?L and the L-M parameter. The calculated values of the two-phase heat transfer coefficient h2? based on pure diesel and pure water suggest that diesel is a better reference fluid since the average error is much smaller compared to pure water as reference.

  2. Design evaluation of flow-induced vibrations for a large shell and tube type nuclear heat exchanger

    International Nuclear Information System (INIS)

    Increased flow requirements for a large sized shell and tube type nuclear heat exchanger during advanced stage of manufacturing required re-evaluation of the Design to withstand flow-induced vibrations and suggest suitable Design alternatives within the constraints imposed at this advanced stage of manufacturing. Detailed flow-induced vibration analysis was done and two design alternatives offered. The first one consisted in attaching a wire-netted grid mounted alongside the baffle supports and the second considered removal of tubes from the vibration prone double span window region, which was counter-checked for heat-transfer adequacy requirement. Of the two alternatives, the second one was accepted due to its easy application at the advanced manufacturing stage. While the application of the wire-netted grid was not considered in the specific case, this might find application wherever the vibration prone double span tubes cannot be removed due to heat transfer requirements of Design

  3. Design and Development of Shell and Tube Heat Exchanger for Harar Brewery Company Pasteurizer Application (Mechanical and Thermal Design

    Directory of Open Access Journals (Sweden)

    Dawit Bogale

    2014-10-01

    Full Text Available A heat exchanger is a device that is used to transfer thermal energy (enthalpy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures and in thermal contact[1].From different types of heat exchangers the shell and tube heat exchangers with straight tubes and single pass is to be under study. Here the redesign takes place because of temperature fluctuation at the 9th zone of the pasteurizer in the Harar Brewery Company. Thermal and mechanical design is run in order to optimize the output temperature of the cold fluid at the last heat exchanger in which it is sprayed on the beer ready for customer use. In thermal design part geometry optimization is done through trial and error. And for Mechanical design part the natural frequency& vortex shedding of different components of heat exchangers are investigated through governing equations of vibrations under dynamic fluid with in tubes. Using computational fluid dynamics (CFD the heat transfer of the two fluid is investigated using FEM simulation software’s Gambit1.3 and Fluent 6.1and the performance of the STHEx determined in terms of variables such as pressure, temperature, flow rate, energy input/output, mass flow rate and mass transfer rate that are of particular interest in STHEx analysis.

  4. Impacto ecológico de los Intercambiadores de calor de tubo y coraza; Ecological impact of Shell and tube heat exchangers

    Directory of Open Access Journals (Sweden)

    Maida Bárbara Reyes Rodríguez

    2015-04-01

    Full Text Available Los intercambiadores de calor de tubo y coraza son de los equipos más importantes en la industria. Su diseño termodinámico se basa en el coeficiente global de transferencia de calor y la caída de presión total. En 2007 se estableció una nueva propiedad termodinámica denominada “Entransía”, que expresa la capacidad de un cuerpo de transferir calor. A la pérdida de esa capacidad se le denomina “Disipación de Entransía”. Para evaluar el impacto ecológico de las máquinas térmicas, Angulo-Brown creó en 1991 la llamada función ecológica. En el presente trabajo se combinó la disipación de entransía con la función ecológica y se creó una nueva expresión para evaluar el impacto ambiental de los intercambiadores de calor. Se realizó además la optimización muti-objetivo de estos equipos. Fueron utilizadas como funciones objetivo la función ecológica y el costo. Para realizar la optimización se utilizó el método de los Algoritmos Genéticos.Shell and tube heat exchangers are ones the most important equipment in the industry. Their thermodynamic design is based on the global heat transference coefficient and the pressure drop. In 2007 was settled a new thermodynamic property denominated “Entransy”, which expresses the capacity of a body to transfer heat. The loss of this capacity is denominated “Entransy Dissipation”. For evaluating the ecological impact of thermal machines, Angulo-Brown created in 1991 the “ecological function”. In this paper the“entransy dissipation” and the ecological function were combined and a new expression for evaluating the ecological impact of shell and tube heat exchangers was created. A multi-objective optimization of this equipment wasalso realized. The ecological function and the cost wereused as objective functions. For carry out the optimization the method of the Genetic Algorithms was used.

  5. Impacto ecológico de los Intercambiadores de calor de tubo y coraza / Ecological impact of Shell and tube heat exchangers

    Scientific Electronic Library Online (English)

    Maida Bárbara, Reyes Rodríguez; Jorge Laureano, Moya Rodríguez; Oscar Miguel, Cruz Fonticiella.

    2015-04-01

    Full Text Available Los intercambiadores de calor de tubo y coraza son de los equipos más importantes en la industria. Su diseño termodinámico se basa en el coeficiente global de transferencia de calor y la caída de presión total. En 2007 se estableció una nueva propiedad termodinámica denominada "Entransía", que expre [...] sa la capacidad de un cuerpo de transferir calor. A la pérdida de esa capacidad se le denomina "Disipación de Entransía". Para evaluar el impacto ecológico de las máquinas térmicas, Angulo-Brown creó en 1991 la llamada función ecológica. En el presente trabajo se combinó la disipación de entransía con la función ecológica y se creó una nueva expresión para evaluar el impacto ambiental de los intercambiadores de calor. Se realizó además la optimización muti-objetivo de estos equipos. Fueron utilizadas como funciones objetivo la función ecológica y el costo. Para realizar la optimización se utilizó el método de los Algoritmos Genéticos. Abstract in english Shell and tube heat exchangers are ones the most important equipment in the industry. Their thermodynamic design is based on the global heat transference coefficient and the pressure drop. In 2007 was settled a new thermodynamic property denominated "Entransy", which expresses the capacity of a body [...] to transfer heat. The loss of this capacity is denominated "Entransy Dissipation". For evaluating the ecological impact of thermal machines, Angulo-Brown created in 1991 the "ecological function". In this paper the"entransy dissipation" and the ecological function were combined and a new expression for evaluating the ecological impact of shell and tube heat exchangers was created. A multi-objective optimization of this equipment wasalso realized. The ecological function and the cost wereused as objective functions. For carry out the optimization the method of the Genetic Algorithms was used.

  6. Vibration in shell and tube heat exchangers - prediction versus operation (Paper No. 003)

    International Nuclear Information System (INIS)

    The continued demand for improved performance of heat exchangers under serious limitations of cost and space, has led to designs that are more compact with increased flow rates. Though these changes have undoubtedly achieved the improved thermodynamic performance intended, they have at the same time made the heat exchanger tubes susceptible to flow induced vibration. Also, there has been a trend towards higher capacity heat exchangers having increased shell side flow velocities to improve the heat transfer. As a consequence, there has been a significant increase in the incidence of tube failures due to flow induced vibrations. Problems caused by flow induced vibrations like mechanical wear, fatigue failure, acoustic noise and mixing of shell side and tube side fluids are evaluated. (author). 2 figs., 2 tables, 10 refs

  7. Estimated Outlet Temperatures in Shell-and-Tube Heat Exchanger Using Artificial Neural Network Approach Based on Practical Data

    Directory of Open Access Journals (Sweden)

    Hisham Hassan Jasim

    2013-01-01

    Full Text Available The objective of this study is to apply Artificial Neural Network for heat transfer analysis of shell-and-tube heat exchangers widely used in power plants and refineries. Practical data was obtained by using industrial heat exchanger operating in power generation department of Dura refinery. The commonly used Back Propagation (BP algorithm was used to train and test networks by divided the data to three samples (training, validation and testing data to give more approach data with actual case. Inputs of the neural network include inlet water temperature, inlet air temperature and mass flow rate of air. Two outputs (exit water temperature to cooling tower and exit air temperature to second stage of air compressor were taken in ANN.150 sets of data were generated in different days by the reference heat exchanger model to training the network. Regression between desired target and prediction ANN output for training , validation, testing and all samples show reasonably values are equal to one (R=1 . 50 sets of data were generated to test the network and compare between desired and predicated exit temperature (water temp. and air temp. show a good agreement ( .

  8. Techno-economic optimization of a shell and tube heat exchanger by genetic and particle swarm algorithms

    International Nuclear Information System (INIS)

    Highlights: • Calculating pressure drop and heat transfer coefficient by Delaware method. • The accuracy of the Delaware method is more than the Kern method. • The results of the PSO are better than the results of the GA. • The optimization results suggest that yields the best and most economic optimization. - Abstract: The use of genetic and particle swarm algorithms in the design of techno-economically optimum shell-and-tube heat exchangers is demonstrated. A cost function (including costs of the heat exchanger based on surface area and power consumption to overcome pressure drops) is the objective function, which is to be minimized. Selected decision variables include tube diameter, central baffles spacing and shell diameter. The Delaware method is used to calculate the heat transfer coefficient and the shell-side pressure drop. The accuracy and efficiency of the suggested algorithm and the Delaware method are investigated. A comparison of the results obtained by the two algorithms shows that results obtained with the particle swarm optimization method are superior to those obtained with the genetic algorithm method. By comparing these results with those from various references employing the Kern method and other algorithms, it is shown that the Delaware method accompanied by genetic and particle swarm algorithms achieves more optimum results, based on assessments for two case studies

  9. Influence of Ionic Fluid in Counter flow in Shell and Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    N.D.Shirgire

    2014-07-01

    Full Text Available An Ionanofluids are a new and innovative class of heat transfer fluids which exhibit fascinating thermo physical properties compared to their base ionic liquids. In this paper (1-Butyl-3-methylimidazolium chloride (BmimCLionic fluid is used comparison with Distilled Water. Distilled Water is non Ionic form in nature, so, results using (BmimCLis Overall good efficient in heat transfer device, were obtained with experimental work results on thermal conductivity and heat capacity,. As compared to (BmimCL those of their base ionic liquids such as (mineral oils and ethylene glycol etc are less thermophysical properties . as coolants in heat exchanger are also used to access their feasibility and performance in heat transfer devices.

  10. Enhancement of Performance of Shell and Tube Heat Exchanger Using Pertinent Leakage Flow Between Baffle and Tube Bundles

    International Nuclear Information System (INIS)

    In this study, the effects of the leakage flow between the baffle and tube bundles on the performance of a shell and tube heat exchanger (STHE) were examined using the commercial software ANSYS FLUENT v.14. A computational fluid dynamics model was developed for a small STHE with five different cases for the ratio of the leakage cross-sectional area to the baffle cross-sectional area, ranging from 0 to 40%, in order to determine the optimum leakage flow corresponding to the maximum outlet temperature. Using fixed tube wall and inlet temperatures for the shell side of the STHE, the flow and temperature fields were calculated by increasing the Reynolds number from 4952 to 14858. The present results showed that the outlet temperature, pressure drop, and heat transfer coefficient were strongly affected by the leakage flow, as well as the Reynolds number. In contrast with a previous researchers finding that the leakage flow led to simultaneous decreases in the pressure drop and heat transfer rate, the present study found that the pertinent leakage flow provided momentum in the recirculation zone near the baffle plate and thus led to the maximum outlet temperature, a small pressure drop, and the highest heat transfer rate. The optimum leakage flow was shown in the case with a ratio of 20% among the five different cases.

  11. Enhancement of Performance of Shell and Tube Heat Exchanger Using Pertinent Leakage Flow Between Baffle and Tube Bundles

    Energy Technology Data Exchange (ETDEWEB)

    Hap, Nguyen Van; Lee, Geun Sik [Ulsan University, Ulsan (Korea, Republic of)

    2015-03-15

    In this study, the effects of the leakage flow between the baffle and tube bundles on the performance of a shell and tube heat exchanger (STHE) were examined using the commercial software ANSYS FLUENT v.14. A computational fluid dynamics model was developed for a small STHE with five different cases for the ratio of the leakage cross-sectional area to the baffle cross-sectional area, ranging from 0 to 40%, in order to determine the optimum leakage flow corresponding to the maximum outlet temperature. Using fixed tube wall and inlet temperatures for the shell side of the STHE, the flow and temperature fields were calculated by increasing the Reynolds number from 4952 to 14858. The present results showed that the outlet temperature, pressure drop, and heat transfer coefficient were strongly affected by the leakage flow, as well as the Reynolds number. In contrast with a previous researchers finding that the leakage flow led to simultaneous decreases in the pressure drop and heat transfer rate, the present study found that the pertinent leakage flow provided momentum in the recirculation zone near the baffle plate and thus led to the maximum outlet temperature, a small pressure drop, and the highest heat transfer rate. The optimum leakage flow was shown in the case with a ratio of 20% among the five different cases.

  12. Investigation of the effects of baffle orientation, baffle cut and fluid viscosity on shell side pressure drop and heat transfer coefficient in an e-type shell and tube heat exchanger

    OpenAIRE

    Mohammadi, Koorosh

    2011-01-01

    The commercial CFD code FLUENT is used to determine the effect of baffle orientation and baffle cut as well as viscosity of the working fluid on the shell-side heat transfer and pressure drop of a shell and tube heat exchanger. The shell and tube heat exchangers considered follow the TEMA standards. The investigation has been completed in three stages: 1. The shell and tube heat exchanger consists of 660 plain tubes with fixed outside diameter which are arranged in a triangular layout. Hor...

  13. Design Optimization of Shell and Tube Heat Exchanger by Vibration Analysis

    OpenAIRE

    S.H. Gawande; A. A Keste; L. G Navale; M. R. Nandgaonkar; V. J Sonawane; U. B Ubarhande

    2011-01-01

    In this paper a simplified approach to optimize the design of Shell Tube Heat Exchanger [STHE] by flow induced vibration analysis [FVA] is presented. The vibration analysis of STHE helps in achieving optimization in design by prevention of tube failure caused due to flow induced vibration. The main reason for tube failure due to flow induced vibration is increased size of STHE. It is found that in case of increased size of STHE, the surface area and number of tubes increases, thus the underst...

  14. The modelling of particle build up in shell-and-tube heat exchangers due to process cooling water / Christiaan Jacob Ghyoot

    OpenAIRE

    Ghyoot, Christiaan Jacob

    2013-01-01

    Sasol Limited experiences extremely high particulate fouling rates inside shell-and-tube heat exchangers that utilize process cooling water. The water and foulants are obtained from various natural and process sources and have irregular fluid properties. The fouling eventually obstructs flow on the shell side of the heat exchanger to such an extent that the tube bundles have to be replaced every nine months. Sasol requested that certain aspects of this issue be addressed. To...

  15. Shell side numerical analysis of a shell and tube heat exchanger considering the effects of baffle inclination angle on fluid flow using CFD

    Directory of Open Access Journals (Sweden)

    Raj Karuppa Thundil R.

    2012-01-01

    Full Text Available In this present study, attempts were made to investigate the impacts of various baffle inclination angles on fluid flow and the heat transfer characteristics of a shell-and-tube heat exchanger for three different baffle inclination angles namely 0°,10° and 20°. The simulation results for various shell and tube heat exchangers, one with segmental baffles perpendicular to fluid flow and two with segmental baffles inclined to the direction of fluid flow are compared for their performance. The shell side design has been investigated numerically by modeling a small shell-and-tube heat exchanger. The study is concerned with a single shell and single side pass parallel flow heat exchanger. The flow and temperature fields inside the shell are studied using non-commercial CFD software tool ANSYS CFX 12.1. For a given baffle cut of 36 %, the heat exchanger performance is investigated by varying mass flow rate and baffle inclination angle. From the CFD simulation results, the shell side outlet temperature, pressure drop, recirculation near the baffles, optimal mass flow rate and the optimum baffle inclination angle for the given heat exchanger geometry are determined.

  16. A new method to calculate pressure drop and shell-side heat transfer coefficient in a shell-and-tube heat exchanger

    International Nuclear Information System (INIS)

    A new method to calculate pressure drop (?p) and shell-side heat transfer coefficient (h sub(c)) in a shell-and-tube heat exchanger with segmental baffles is presented. The method is based on the solution of the equations of conservation of mass and momentum between two baffles. The calculated distributions of pressure and velocities given respectively, ?p and h sub(c). The values of ?p and h sub(c) are correlated for a given geometry whit the shell side fluid properties and flow rate. The calculated and experimental results agree very well for a U-Tube heat exchanger. (Author)

  17. Cálculo simplificado de vibraciones en los intercambiadores de calor de tubo y coraza con fluidos líquidos / Simplified calculation of vibrations in shell and tube heat exchangers with liquids

    Scientific Electronic Library Online (English)

    Maida Bárbara, Reyes-Rodríguez; Jorge Laureano, Moya-Rodríguez; Rafael, Goytisolo-Espinosa.

    2014-08-01

    Full Text Available Un problema muy serio a tener en cuenta en el diseño mecánico de los intercambiadores de calor de tubo y coraza son las vibraciones inducidas en los tubos por el paso del fluido. La vibración de los tubos de los intercambiadores de calor de tubo y coraza es un factor que limita de manera importante [...] la operación de estos equipos. Los procesos dinámicos de los fluidos no estacionarios que ocurren durante el flujo producen vibraciones. Éstas son pulsaciones turbulentas de la presión (flujo turbulento), iniciación del vórtice y separación de los tubos durante el cruce de las corrientes, interacción hidro elástica de los montajes de los elementos transmisores del calor (tubos) con el flujo, y fenómenos acústicos. En el presente trabajo se describe el procedimiento a seguir para el cálculo de las vibraciones en los intercambiadores de calor de tubo y coraza. Abstract in english A very serious problem to consider in the mechanical design of Shell and Tube Heat Exchangers is the vibrations induced in the tubes by the fluid pass. The vibration of the tubes of the Shell and Tube Heat Exchangers is a factor that limits the operation of these equipments in important way. The dyn [...] amic processes of the nonstationary fluids that happen during the flow produce vibrations. These are turbulent pulsations of the pressure (turbulent flow), initiation of the vortex and separation of the tubes during the crossing of the currents, hydro elastic interaction of the assemblies of the transmitting elements of the heat (tubes) with the flow, and acoustic phenomena. In the present work the procedure for the calculation of the vibrations in Shell and Tube Heat Exchangers is described.

  18. Numerical simulation of vortex induced vibration and related parameters in cross flow shell and tubes heat exchanger: a review

    International Nuclear Information System (INIS)

    This paper presents a brief review of studies on cross flow induced vortices in downside of tubes which leads to vibration. Two types of vibrations have been studied for tubes in cross flow: first vibration of the tube due to vortex shedding which is important primarily in cross flow but this vibration disappears in slug flow or froth flow regions which are important in numerous heat exchangers, secondly fluid elastic excitation which is most dangerous mechanism in heat exchanger tube bundles. The paper also presents the other parameters such as temperature variation on tube, pressure effect, lift and drag generation and their influence on heat exchanger tubes, different models comparison and tube size effect of tubes for vortices. (author)

  19. Automatización y optimización del diseño de intercambiadores de calor de tubo y coraza mediante el método de Taborek / Automatization and optimization of shell and tube heat exchangers design using the method of Taborek

    Scientific Electronic Library Online (English)

    Maida Bárbara, Reyes-Rodríguez; Jorge-Laureano, Moya-Rodríguez; Oscar-Miguel, Cruz-Fonticiella; Eduardo-Miguel, Fírvida-Donéstevez; José-Alberto, Velázquez-Pérez.

    2014-04-01

    Full Text Available Los intercambiadores de calor del tipo de coraza y tubo constituyen la parte más importante de los equipos de transferencia de calor sin combustión en las plantas de procesos químicos. Existen en la literatura numerosos métodos para el diseño de Intercambiadores de calor de tubo y coraza. Entre los [...] más conocidos se encuentran el Método de Kern, el Método de Bell Delaware, el Método de Tinker, el Método de Wills and Johnston y el Método de Taborek. El presente trabajo tiene como objetivo describir y automatizar el método de Taborek. Se realiza además la optimización del Costo del Intercambiador de Calor mediante el método de Recocido Simulado y el método de los algoritmos genéticos. Se puede concluir que la optimización por ambos métodos arroja resultados similares, disminuyendo apreciablemente el costo del intercambiador optimizado. Abstract in english Shell and tube heat exchangers are the most important equipment for heat transfer without combustion in plants of chemical processes.There are many methods for designing shell and tube heat exchangers in literature. Among the most known are the Kern´s Method, the Method of Bell Delaware, the Method [...] of Tinker, the Method of Wills and Johnston and the Method of Taborek. The objective of this paper is to describe and automate the Taborek´s method. It is also realized and optimization of the heat exchanger cost using the genetic algorithm and Simulated Annealing. It can be concluded that the optimization using both methods conduces to similar results, diminishing considerably the optimized exchanger cost

  20. Software para la enseñanza de la dinámica y control de intercambiadores de calor de tubos y coraza / Educational software for the teaching of the dynamics and control of shell and tube heat exchangers

    Scientific Electronic Library Online (English)

    Fiderman, Machuca; Oscar, Urresta.

    2008-06-01

    Full Text Available Este trabajo presenta la estructura de un software desarrollado para la enseñanza y aprendizaje de la dinámica y control de intercambiadores de calor de tubos y coraza. El programa presenta, de manera numérica y gráfica, el comportamiento dinámico en lazo abierto y cerrado del proceso para diferente [...] s parámetros de diseño y condiciones de operación variables. El software permite modificar condiciones tanto de operación como de diseño, por ejemplo, temperatura y caudales de entrada a los tubos y coraza, número y longitud de tubos, número de pasos, diámetro externo e interno de los tubos, diámetro interno de coraza y factor de ensuciamiento. Abstract in english The present work shows the software structure developed for teaching and learning of the dynamics and control of shell and tubes heat exchangers. The program shows (numerical and graphical mode) the dynamic behavior in open and closed loop under different design parameters and variable operations co [...] nditions. The software allows changing operation and design conditions such as temperature and flow inlet in shells and tubes, number and length of tubes, inside and outside diameter of tubes, number of passes, shell outside diameter and fouling factor.

  1. Effect of the sequence of tube rolling in a tube bundle of a shell and tube heat exchanger on the stress-deformed state of the tube sheet

    Science.gov (United States)

    Tselishchev, M. F.; Plotnikov, P. N.; Brodov, Yu. M.

    2015-11-01

    Rolling the tube sheet of a heat exchanger with U-shaped tubes, as exemplified by the vapor cooler GP-24, was simulated. The simulation was performed using the finite element method with account of elas- tic-plastic properties of the tube and tube sheet materials. The simulation consisted of two stages; at the first stage, maximum and residual contact stress in the conjunction of a separate tube and the tube sheet was determined using the "equivalent sleeve" model; at the second stage, the obtained contact stress was applied to the hole surface in the tube sheet. Thus, different tube rolling sequences were simulated: from the center to the periphery of the tube sheet and from the periphery to the center along a spiral line. The studies showed that the tube rolling sequence noticeably influences the value of the tube sheet residual deflection for the same rolling parameters of separate tubes. Residual deflection of the tube sheet in different planes was determined. It was established that the smallest residual deflection corresponds to the tube rolling sequence from the periphery to the center of the tube sheet. The following dependences were obtained for different rolling sequences: maximum deformation of the tube sheet as a function of the number of rolled tubes, residual deformation of the tube sheet along its surface, and residual deflection of the tube sheet as a function of the rotation angle at the periphery. The preferred sequence of tube rolling for minimizing the tube sheet deformation is indicated.

  2. Improving heat transfer efficiency of shell and tube evaporators of marine refrigerating installations

    Directory of Open Access Journals (Sweden)

    Bukin Vladimir Grigorievich

    2013-04-01

    Full Text Available The results of investigations to determine the heat transfer of refrigerant R410A in shell and tube evaporators of marine refrigerating installations are presented. The effect of surface configuration and oil concentration on the nucleate boiling on heat transfer coefficients of different surfaces is investigated. The results of the study allow making a conclusion that the use of tubes with the developed surface geometry provides increase in heat transfer coefficient. It is advisable to replace the standard fins tubes of marine flooded shell and tube evaporator with tubes with enhanced surfaces.

  3. The enhancement of steam condensation heat transfer in a horizontal shell and tube condenser by addition of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Philpott, Chris; Deans, Joe [Auckland Univ., Dept. of Mechanical Engineering, Auckland (New Zealand)

    2004-08-01

    This paper reports on the rates of condensation heat transfer for weak ammonia-water mixtures in a horizontal, shell and tube condenser. It is shown that for inlet ammonia concentrations in the range 0.2-0.9 wt.% the average condensation heat transfer for the condenser was enhanced by up to 14%. Furthermore, local enhancement of the condensation heat transfer of up to 34% occurred at local bulk vapour concentrations between 0.2 and 2 wt.% ammonia. This enhancement was caused by the Marangoni effect which produced a disturbed, turbulent banded condensate film and a corresponding drop in the thermal resistance of the condensate film. (Author)

  4. COMPARATIVEANALYSIS OF ADVANCED CONTROLLERS IN A HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    Mr. P.Sivakumar

    2013-01-01

    Full Text Available Temperature control of the shell and tube heat exchanger is characteristics of nonlinear, time varying and time lag. Since the temperature control with conventional PID controller cannot meet a wide range of precision temperature control requirement, we design temperature control system of the shell and tube heat exchanger by combining fuzzy and PID control methods in this paper. The simulation and experiments are carried out; making a comparison with conventional PID control showing that fuzzy PID strategy can efficiently improve the performance of the shell and tube heat exchanger.

  5. Boiling heat-transfer coefficient variation for R407C inside horizontal tubes of a refrigerating vapour-compression plant's shell-and-tube evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Torrella, Enrique [Department of Applied Thermodynamics, Camino de Vera, 14, Polytechnic University of Valencia, E-46022 Valencia (Spain); Navarro-Esbri, Joaquin; Cabello, Ramon [Department of Technology, Campus de Riu Sec,University Jaume I, E-12071 Castellon (Spain)

    2006-03-01

    The present paper presents experimental results obtained from a refrigerating vapour-compression plant's shell-and-tube (1-2) evaporator working with R407C. Several tests have been carried out to study the influence of the evaporating pressure and the refrigerant's mass flow rate on the refrigerant's boiling heat-transfer coefficient inside horizontal tubes. This work has been performed by analyzing the variations of the evaporator's overall thermal-resistance, computed using the effectiveness-NTU method, considering the influence of pressure drops and glide at the evaporator, and finally transferring the results and conclusions to the boiling heat-transfer coefficient. It has been observed that the variations of the boiling heat-transfer coefficient show a dependence on the evaporating temperature and the refrigerant's mass-flow rate, which has been analyzed in the test range. [Author].

  6. Chapter 11. Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Rafferty, Kevin D.; Culver, Gene

    1998-01-01

    Most geothermal fluids, because of their elevated temperature, contain a variety of dissolved chemicals. These chemicals are frequently corrosive toward standard materials of construction. As a result, it is advisable in most cases to isolate the geothermal fluid from the process to which heat is being transferred. The task of heat transfer from the geothermal fluid to a closed process loop is most often handled by a plate heat exchanger. The two most common types used in geothermal applications are: bolted and brazed. For smaller systems, in geothermal resource areas of a specific character, downhole heat exchangers (DHEs) provide a unique means of heat extraction. These devices eliminate the requirement for physical removal of fluid from the well. For this reason, DHE-based systems avoid entirely the environmental and practical problems associated with fluid disposal. Shell and tube heat exchangers play only a minor role in low-temperature, direct-use systems. These units have been in common use in industrial applications for many years and, as a result, are well understood. For these reasons, shell and tube heat exchangers will not be covered in this chapter.

  7. Optimization of a Shell and Tube Condenser using Numerical Method

    Directory of Open Access Journals (Sweden)

    Pradeep Wagh

    2015-07-01

    Full Text Available The purpose of this study was to investigate the effect of installation of the tube external surfaces, their parameter and variable in a shell-and-tube condenser. Variation of heat transfer coefficient with each variable of shell and tube condenser was measured each test. The optimization tube outside diameter size was analyzed and use extended surface area attached tube with tube material and tube layout and arrangement (Number of tube a triangular or hexagonal arrangement on shell-and tube condenser. The computer programming was used to get faster output in less time. Results suggest that mean heat transfer coefficient in variable condition were mainly at velocity is fixed. And also average additional surfaces and tube layout and the arrangement comparison with the quantity of the heat transfer.

  8. Maintenance experience on process heat exchangers in Dhruva reactor

    International Nuclear Information System (INIS)

    Dhruva a 100 MW (thermal) high flux research reactor has two types of heat exchangers operating in various process system i.e. shell and tube type and plate type. Annexure-1 indicates various heat exchangers in different systems of the reactor. Among the heat exchangers, those used in main coolant system, vault and shield cooling system did not warrant regular overhaul after commissioning but for periodic fastness, tightness checks in view of the high standard of purity and close chemistry control on the process fluids on both the sides of the heat exchangers. In addition, the heat transfer performance of these heat exchangers have been consistent without any degradation. Therefore shell and tube type heat exchangers in process water system and plate type heat exchangers in process water and Spent Fuel Storage Building (SFSB) bay water recirculation systems are typically chosen for highlighting the maintenance experience. Maintenance experience on process heat exchangers is given. 4 ills

  9. Delaware Method Improvement for the Shell and Tubes Heat Exchanger Design

    OpenAIRE

    Miguel Toledo-Velázquez; Pedro Quinto-Diez; Juan C. Alzelmetti-Zaragoza; Sergio R. Galvan; Juan Abugaber-Francis; Arturo Reyes-León

    2014-01-01

    In this paper the Delaware Method published in 1963 is analyzed and upgraded with using correction factors which take into account the undesirable currents of the mean flow. However, this method presents graphically these correction factors which imply an impediment to fulfill the software calculations. Thus, the equations corresponding to the correction factor equations and a Fortran 77 numerical program were established. This system is given to explore ...

  10. Computation of two-dimensional isothermal flow in shell-and-tube heat exchangers

    International Nuclear Information System (INIS)

    A computational procedure is outlined whereby two-dimensional isothermal shell-side flow distributions can be calculated for tube bundles having arbitrary boundaries and flow blocking devices, such as sealing strips, defined in arbitrary locations. The procedure is described in some detail and several computed results are presented to illustrate the robustness and generality of the method

  11. Study on flow-induced vibration and anti-vibration measures of nuclear heat exchanger

    International Nuclear Information System (INIS)

    Nuclear heat exchanger is the important equipment of nuclear power plant. Shell-and-tube is the ordinary style used in heat exchanger structure. Unreasonable design will make tubes vibrate and maybe lead tubes broken. Then the running safety of nuclear power plant is influenced. The flow-induced vibration mechanism is studied. Based on structure characteristic of shell-and-tube heat exchange, the failure modes of heat exchange caused by flow-induced vibration are analyzed roundly. Specific approaches are presented to prevent nuclear heat exchange from vibration. (authors)

  12. Flow and vibration analysis to upgrade a CANDU heat exchanger

    International Nuclear Information System (INIS)

    This paper presents an example to illustrate the use of two-dimensional flow calculations to optimize the location of sealing strips and rods in a shell-and-tube heat exchanger. This is done to minimize flow maldistribution and potential flow-induced vibration damage without significantly de-rating the unit. The calculations are carried out for an existing design

  13. Heat exchanger with intermediate evaporating and condensing fluid

    International Nuclear Information System (INIS)

    A shell and tube-type heat exchanger, such as a liquid sodium-operated steam generator for use in nuclear reactors, comprises a shell containing a primary fluid tube bundle, a secondary fluid tube bundle at higher elevation, and an intermediate fluid vaporizing at the surface of the primary fluid tubes and condensing at the surface of the secondary fluid tubes

  14. Studying the Thermal and Hydraulic Characteristics of a Shell-and-Tube Water Heater Equipped with Dimpled Heat-Transfer Tubes to Enhance Heat Transfer

    Science.gov (United States)

    Balunov, B. F.; Gotovskii, M. A.; Permyakov, V. A.; Permyakov, K. V.; Shcheglov, A. A.; Il'in, V. A.; Saikova, E. N.; Sal'nikov, V. V.

    2008-01-01

    Results of a thermal-hydraulic investigation of a steam-water heater equipped with dimpled heat-transfer tubes are presented. It is shown that heat transfer on the internal dimpled surface has risen by 60% with their drag increased by a factor of 2.1.

  15. Experimental Investigation Of Heat Transfer Characteristics Of Nanofluid Using Parallel Flow, Counter Flow And Shell And Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Dharmalingam R.

    2015-12-01

    Full Text Available Ch?odzenie jest niezb?dne dla w?a?ciwego funkcjonowania i niezawodno?ci ró?norodnych produktów, jak urz?dzenia elektroniczne, komputery, samochody, systemy laserowe wielkiej mocy, itp. W sytuacji wzrostu obci??enia cieplnego i strumieni ciep?a wytwarzanych przez urz?dzenia przemys?owe, ch?odzenie jest jednym z najwa?niejszych wyzwa? wyst?puj?cych w ró?nych ga??ziach przemys?u, transporcie, mikroelektronice, itp. P?ynami, które zwykle s? u?ywane do odprowadzania ciep?a z tych urz?dze? s? woda, glikol etylenowy i oleje. Nanop?yny, opracowane w ostatnim czasie, wykazuj? generalnie lepsze charakterystyki przewodnictwa cieplnego ni? woda. Przedstawiona praca stanowi podsumowanie bada? do?wiadczalnych nad wymuszonym, konwekcyjnym odprowadzaniem ciep?a i charakterystykami przep?ywu nanop?ynu sk?adaj?cego si? z wody i cz?steczek Al2O3 (w 1% st??eniu obj?to?ciowym w warunkach laminarnego przep?ywu wspó?pr?dowego i przeciwpr?dowego w p?aszczowych i rurowych wymiennikach ciep?a. W przedstawionych badaniach u?yto cz?stek Al2O3 o ?rednicy ok. 50 nm. Wybrano trzy ró?ne pr?dko?ci przep?ywu masy, opisano wyniki eksperymentów. Wyniki te wskazuj?, ?e ca?kowity wspó?czynnik odprowadzania ciep?a i bezwymiarowa liczba Nusselta nanop?ynu s?, przy tej samej pr?dko?ci przep?ywu masy i temperaturze na wlocie, nieznacznie wy?sze, ni? dla samego p?ynu bazowego. Z wyników do?wiadczalnych wynika, ?e ca?kowity wspó?czynnik odprowadzania ciep?a wzrasta wraz z pr?dko?ci? przep?ywu masy. Pokazano, ?e gdy wzrasta pr?dko?? przep?ywu masy, ca?kowity wspó?czynnik odprowadzania ciep?a wraz z bezwymiarow? liczb? Nusselta ostatecznie wzrastaj?, niezale?nie od kierunku przep?ywu. Stwierdzono tak?e, ?e ze wzrostem pr?dko?ci przep?ywu masy warto?? LMTD (?redniej logarytmicznej ró?nicy temperatur ostatecznie maleje, niezale?nie od kierunku przep?ywu.

  16. Joint economic optimization of heat exchanger design and maintenance policy

    OpenAIRE

    Antonio C. Caputo; Pelagagge, Pacifico M.; Salini, Paolo

    2011-01-01

    In this paper a new approach to shell and tube heat exchanger optimization is presented based on the minimization of the life-cycle cost. The method allows the joint optimization of both the equipment design and the cleaning policy. Economic savings resulting from the proposed design procedure are relevant especially when large sized equipment is involved or when a large number of small sized units are installed. At first, a thermal design procedure defines the heat transfer area as well as f...

  17. Thermal analysis of baffled shell and tube type EGR cooler for different types of tubes using CFD

    OpenAIRE

    Ibrahim Hussain Shah; , Avinash Kumar Namdeo*2

    2014-01-01

    Exhaust Gas Recirculation (EGR) technique using EGR cooler reduces the NOx content from the tailpipe emission of Diesel engines. Commercial computational fluid dynamics (CFD) code is used to solve and simulate the flow-fields and temperature distribution of fluids inside the EGR cooler. In this investigation two models (model-a and model-b) of EGR coolers are developed using Pro/Engineer Wildfire 4.0 software. Model-a is a single pass baffled shell and tube heat exchanger with...

  18. A Simple Tubesheet Layout Program for Heat Exchangers

    OpenAIRE

    Murali, S; Y. B. Rao

    2008-01-01

    The development of tubesheet layout program for shell and tube heat exchangers is presented in this study. Program is written in AutoLISP language, which provides standard tubesheet layout drawing as per standard codes and non standard tubsheet in AutoCAD Environment. The program computes the optimal number of tube count and lays out drawing with respecting constraints, including the shell ID, number of passes, center to center distance of tubes and tube outer diameter. Tubesheet layout drawi...

  19. The Optimum Selection and Drawing Output Program Development of Shell and Tube Type Oil Cooler

    International Nuclear Information System (INIS)

    Shell and Tube type Oil Cooler is widely used for hydraulic presses, die casting machines, generation equipments, machine tools and construction heavy machinery. Temperature of oil in the hydraulic system changes viscosity and thickness of oil film. They have a bad effect to performance and lubrication of hydraulic machinery, so it is important to know exactly the heat exchanging efficiency of oil cooler for controlling oil temperature. But most Korean manufacturers do not have test equipment for oil cooler, so they cannot carry out the efficiency test of oil cooler and it is impossible to verify its performance. This paper includes information of construction of necessary utilities for oil cooler test and design and manufacture of test equipment. One can select the optimum product by obtaining performance data through tests of various kinds of oil coolers. And also the paper developed a program which can be easily used for design of 2D and 3D drawings of oil cooler

  20. The Optimum Selection and Drawing Output Program Development of Shell and Tube Type Oil Cooler

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. B.; Kim, T. S.; Ko, J. M [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2007-07-01

    Shell and Tube type Oil Cooler is widely used for hydraulic presses, die casting machines, generation equipments, machine tools and construction heavy machinery. Temperature of oil in the hydraulic system changes viscosity and thickness of oil film. They have a bad effect to performance and lubrication of hydraulic machinery, so it is important to know exactly the heat exchanging efficiency of oil cooler for controlling oil temperature. But most Korean manufacturers do not have test equipment for oil cooler, so they cannot carry out the efficiency test of oil cooler and it is impossible to verify its performance. This paper includes information of construction of necessary utilities for oil cooler test and design and manufacture of test equipment. One can select the optimum product by obtaining performance data through tests of various kinds of oil coolers. And also the paper developed a program which can be easily used for design of 2D and 3D drawings of oil cooler.

  1. Application of intensified heat transfer for the retrofit of heat exchanger network

    International Nuclear Information System (INIS)

    Highlights: → Novel design approach for the retrofit of HEN based on intensified heat transfer. → Development of a mathematical model to evaluate shell-and-tube heat exchanger performances. → Identification of the most appropriate heat exchangers requiring heat transfer enhancements in the heat exchanger network. -- Abstract: A number of design methods have been proposed for the retrofit of heat exchanger networks (HEN) during the last three decades. Although considerable potential for energy savings can be identified from conventional retrofit approaches, the proposed solutions have rarely been adopted in practice, due to significant topology modifications required and resulting engineering complexities during implementation. The intensification of heat transfer for conventional shell-and-tube heat exchangers can eliminate the difficulties of implementing retrofit in HEN which are commonly restricted by topology, safety and maintenance constraints, and includes high capital costs for replacing equipment and pipelines. This paper presents a novel design approach to solve HEN retrofit problems based on heat transfer enhancement. A mathematical model has been developed to evaluate shell-and-tube heat exchanger performances, with which heat-transfer coefficients and pressure drops for both fluids in tube and shell sides are obtained. The developed models have been compared with the Bell-Delaware, simplified Tinker and Wills-Johnston methods and tested with the HTRI (registered) and HEXTRAN (registered) software packages. This demonstrates that the new model is much simpler but can give reliable results in most cases. For the debottlenecking of HEN, four heuristic rules are proposed to identify the most appropriate heat exchangers requiring heat transfer enhancements in the HEN. The application of this new design approach allows a significant improvement in energy recovery without fundamental structural modifications to the network.

  2. Heat exchanger

    International Nuclear Information System (INIS)

    Heat exchangers for use in uranium enrichment plant are subject to particularly stringent safety requirements and should be capable of being repaired and maintained quickly. It is proposed to improve a heat exchanger which has a roller type of design consisting of heat exchanger tubes arranged around a core tube, which are connected together in tube floors. According to the invention the tube floors are connected solidly to the outer jacket (possibly via intermadiate pieces), while the heat exchanger tubes end at the side near the inside of the jacket in the tube floors. Manufacture can be further simplified if core tube, roller and outer jacket which are solidly connected form a compact unit. (UWI)

  3. Predicted and measured velocity distribution in a model heat exchanger

    International Nuclear Information System (INIS)

    This paper presents a comparison between numerical predictions, using the porous media concept, and measurements of the two-dimensional isothermal shell-side velocity distributions in a model heat exchanger. Computations and measurements were done with and without tubes present in the model. The effect of tube-to-baffle leakage was also investigated. The comparison was made to validate certain porous media concepts used in a computer code being developed to predict the detailed shell-side flow in a wide range of shell-and-tube heat exchanger geometries

  4. Evaluation Methodology for Advance Heat Exchanger Concepts Using Analytical Hierarchy Process

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Eung Soo Kim

    2012-07-01

    The primary purpose of this study is to aid in the development and selection of the secondary/process heat exchanger (SHX) for power production and process heat application for a Next Generation Nuclear Reactors (NGNR). The potential options for use as an SHX are explored such as shell and tube, printed circuit heat exchanger. A shell and tube (helical coiled) heat exchanger is a recommended for a demonstration reactor because of its reliability while the reactor design is being further developed. The basic setup for the selection of the SHX has been established with evaluation goals, alternatives, and criteria. This study describes how these criteria and the alternatives are evaluated using the analytical hierarchy process (AHP).

  5. Plate type heat exchanger for Reaktor TRIGA PUSPATI

    International Nuclear Information System (INIS)

    The PUSPATI TRIGA reactor (RTP) reached its first criticality status on 28 June 1982 with an installed capacity of 1 MW. After 26 years in operation, the ageing process has set in and many systems in the reactor need maintenance and replacement. Among these systems, the more critical one is the heat exchanger system. Currently, the shell and tube type heat exchanger is being used. It has been observed that the performance of the heat exchanger has dropped significantly over the years. Visual inspections indicate that the tubes are corroded or even to the extent of being totally blocked. With this in mind and also with the setting up of the new Nuclear Power Division, whose mission includes upgrading the present reactor to 3 MW, the heat exchanger system is essential and a critical component. Literature indicates that the use of plate type exchangers are more efficient than the current shell and tube type. This paper will look into the engineering and safety aspects of using the plate type heat exchanger to the current TRIGA PUSPATI reactor. (Author)

  6. Heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Thurley, J.

    1975-11-06

    This heat exchanger, which heats and evaporates a working fluid with the combustion gases of a burner by a heat exchange fluid, is meant to improve the efficiency considerably by including the container containing the heat exchange fluid, as the radiated heat of the burner, which is otherwise lost, is used in this way. As the hottest parts of the burner and the adjacent distribution channel for the combustion gas are cooled by the heat exchange fluid, the cladding of the burner in fire-resisting material becomes unnecessary. The weight and cost are reduced, and the life of the burner and the accesibility of all parts are improved. A horizontal square outer container contains a similar inner container open at the top of half the length and width of the outer container. The two communicating containers are filled to half their height with the primary medium. An upper and lower chamber, both fed axially with fuel, form the burner together with a connected coaxial turbulence chamber. The greater part (of the burner) and the connected horizontal distribution channel are below the level of the cooling primary. The pipe bundle has the combustion gases, rising from the lower distribution channel and the primary fluid heated by these gases flowing through it and is heated by them, where the secondary medium evaporates. The waste gases rising from the primary medium leave the outer container by two chimney openings at the top of the outer container. The maximum heat emitted per hour is stated to be about 100 million KJoules - compared to about 72 million KJoules according to the previous state of technology. The 180kw approx. of blower power previously required to produce the second output is reduced to about 110kw.

  7. Heat exchanger

    International Nuclear Information System (INIS)

    A heat exchanger having primary and secondary conduits in heat-exchanging relationship is described comprising: at least one serpentine tube having parallel sections connected by reverse bends, the serpentine tube constituting one of the conduits; a group of open-ended tubes disposed adjacent to the parallel sections, the open-ended tubes constituting the other of the conduits, and forming a continuous mass of contacting tubes extending between and surrounding the serpentine tube sections; and means securing the mass of tubes together to form a predetermined cross-section of the entirety of the mass of open-ended tubes and tube sections

  8. Efficiency improvement of the indirect supercritical CO2 turbine system for fast reactors by applying micro-channel intermediate heat exchanger

    International Nuclear Information System (INIS)

    Two types of intermediate heat exchanger, shell-and-tube type and microchannel heat exchanger (MCHE) type, have been designed for a Na-cooled fast reactor with an indirect supercritical CO2 turbine. MCHE is a kind of Printed Circuit Heat Exchanger (PCHE) and it uses sinusoidal offset fins that were developed at the Tokyo Institute of Technology (TIT). Its heat transfer and pressure drop correlations were developed based on CFD analysis results, we recommend: Nu equals 0.186*Re0.61*Pr0.4 and friction factor f equals 0.11*Re-0.17. Design results indicate that the value of pressure drop was less than 1% and was very low for the MCHE compared with 8.65% for the shell-and-tube type. In the MCHE, the flow cross-sectional area is large and the CO2 velocity is small. Therefore, it has similar heat transfer area to that of the shell-and-tube type. Nevertheless, the heat transfer volume is only 8% of that for the shell and tube type due to denser arrangement. Consequently, results revealed that cycle thermal efficiency of 45% was achieved in the fast reactor power plant with an MCHE intermediate heat exchanger installed

  9. Various methods to improve heat transfer in exchangers

    Science.gov (United States)

    Pavel, Zitek; Vaclav, Valenta

    2015-05-01

    The University of West Bohemia in Pilsen (Department of Power System Engineering) is working on the selection of effective heat exchangers. Conventional shell and tube heat exchangers use simple segmental baffles. It can be replaced by helical baffles, which increase the heat transfer efficiency and reduce pressure losses. Their usage is demonstrated in the primary circuit of IV. generation MSR (Molten Salt Reactors). For high-temperature reactors we consider the use of compact desk heat exchangers, which are small, which allows the integral configuration of reactor. We design them from graphite composites, which allow up to 1000°C and are usable as exchangers: salt-salt or salt-acid (e.g. for the hydrogen production). In the paper there are shown thermo-physical properties of salts, material properties and principles of calculations.

  10. The Computation And Analysis Of The Correction Factor Of Heat Transfer Coefficient For The Kartini Reactor S Heat Exchanger

    International Nuclear Information System (INIS)

    The computation and analysis of the heat transfer coefficient correction factor the shell and tube type of the Kartini reactor's heat exchanger (HE) has been carried out. The computation of the correction factor was done by measuring of the actual dimension of HE. As known that the shell and tube type of the Kartini reactor's has been opera-ted for more than 15 years. Due to the scraping and rusting occur at the buffle, the total heat transfer coefficient correction factor Ft was decrease. At the later computation, it is found that it's value is 0,4669 or differ of 0,1331 compared to the prediction standard value. So far, if the rusting and scraping of the secondary water coolant to the buffle is linear to the earlier HE's operation time, it is predicted that the function of the buffle will crisis approximately in the year of 2002/2003 or 7,5 years again

  11. A Numerical Algorithm and a Graphical Method to Size a Heat Exchanger

    DEFF Research Database (Denmark)

    Berning, Torsten

    2011-01-01

    This paper describes the development of a numerical algorithm and a graphical method that can be employed in order to determine the overall heat transfer coefficient inside heat exchangers. The method is based on an energy balance and utilizes the spreadsheet application software Microsoft Excel......TM. The application is demonstrated in an example for designing a single pass shell and tube heat exchanger that was developed in the Department of Materials Technology of the Norwegian University of Science and Technology (NTNU) where water vapor is superheated by a secondary oil cycle. This approach can...... be used to reduce the number of hardware iterations in heat exchanger design....

  12. State-of-the-art survey of joinability of materials for OTEC heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Beaver, R. J.

    1978-12-01

    Literature and industrial sources were surveyed to assess, on the basis of apparent economics and reliability, the joinability of both shell-and-tube and compact ocean thermal energy conversion (OTEC) heat exchangers. A no-leak requirement is mandatory to prevent mixing seawater and the ammonia working fluid. The operating temperature range considered is 7 to 28/sup 0/C (45 to 82/sup 0/F). Materials evaluated were aluminum, titanium, copper--nickel, AL-6X austenitic stainless steel, singly and in combination with steel and concrete. Many types of welding and brazing processes, roller expansion, magnaforming, O-ring sealing, and adhesive bonding were considered. The automatic gas tungsten-arc welding process and explosion welding processes are the only two joining processes that now appear to offer the high reliability required of no-leak shell-and-tube heat exchangers. Of these two processes, the gas tungsten-arc welding process appears to be the more economically attractive.

  13. Segmented heat exchanger

    Science.gov (United States)

    Baldwin, Darryl Dean (Lafayette, IN); Willi, Martin Leo (Dunlap, IL); Fiveland, Scott Byron (Metamara, IL); Timmons, Kristine Ann (Chillicothe, IL)

    2010-12-14

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  14. Effectiveness of evolutionary algorithms for optimization of heat exchangers

    International Nuclear Information System (INIS)

    Highlights: • Design optimization of shell and tube heat exchangers. • Comparing performance of three evolutionary optimization algorithms. • Conducting comprehensive simulations for design optimization. • Cuckoo search demonstrates the best performance. - Abstract: This paper comprehensively investigates performance of evolutionary algorithms for design optimization of shell and tube heat exchangers (STHX). Genetic algorithm (GA), firefly algorithm (FA), and cuckoo search (CS) method are implemented for finding the optimal values for seven key design variables of the STHX model. ?-NTU method and Bell-Delaware procedure are used for thermal modeling of STHX and calculation of shell side heat transfer coefficient and pressure drop. The purpose of STHX optimization is to maximize its thermal efficiency. Obtained results for several simulation optimizations indicate that GA is unable to find permissible and optimal solutions in the majority of cases. In contrast, design variables found by FA and CS always lead to maximum STHX efficiency. Also computational requirements of CS method are significantly less than FA method. As per optimization results, maximum efficiency (83.8%) can be achieved using several design configurations. However, these designs are bearing different dollar costs. Also it is found that the behavior of the majority of decision variables remains consistent in different runs of the FA and CS optimization processes

  15. Heat pipe array heat exchanger

    Science.gov (United States)

    Reimann, Robert C. (Lafayette, NY)

    1987-08-25

    A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.

  16. Online performance assessment of heat exchanger using artificial neural networks

    Directory of Open Access Journals (Sweden)

    C. Ahilan, S. Kumanan, N. Sivakumaran

    2011-09-01

    Full Text Available Heat exchanger is a device in which heat is transferred from one medium to another across a solid surface. The performance of heat exchanger deteriorates with time due to fouling on the heat transfer surface. It is necessary to assess periodically the heat exchanger performance, in order to maintain at high efficiency level. Industries follow adopted practices to monitor but it is limited to some degree. Online monitoring has an advantage to understand and improve the heat exchanger performance. In this paper, online performance monitoring system for shell and tube heat exchanger is developed using artificial neural networks (ANNs. Experiments are conducted based on full factorial design of experiments to develop a model using the parameters such as temperatures and flow rates. ANN model for overall heat transfer coefficient of a design/ clean heat exchanger system is developed using a feed forward back propagation neural network and trained. The developed model is validated and tested by comparing the results with the experimental results. This model is used to assess the performance of heat exchanger with the real/fouled system. The performance degradation is expressed using fouling factor (FF, which is derived from the overall heat transfer coefficient of design system and real system. It supports the system to improve the performance by asset utilization, energy efficient and cost reduction interms of production loss.

  17. Online performance assessment of heat exchanger using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Ahilan, C.; Kumanan, S. [Department of Production Engineering, National Institute of Technology Tiruchirappalli (India); Sivakumaran, N. [Department of Instrumentation and Control Engineering, National Institute of Technology Tiruchirappalli (India)

    2011-07-01

    Heat exchanger is a device in which heat is transferred from one medium to another across a solid surface. The performance of heat exchanger deteriorates with time due to fouling on the heat transfer surface. It is necessary to assess periodically the heat exchanger performance, in order to maintain at high efficiency level. Industries follow adopted practices to monitor but it is limited to some degree. Online monitoring has an advantage to understand and improve the heat exchanger performance. In this paper, online performance monitoring system for shell and tube heat exchanger is developed using artificial neural networks (ANNs). Experiments are conducted based on full factorial design of experiments to develop a model using the parameters such as temperatures and flow rates. ANN model for overall heat transfer coefficient of a design/ clean heat exchanger system is developed using a feed forward back propagation neural network and trained. The developed model is validated and tested by comparing the results with the experimental results. This model is used to assess the performance of heat exchanger with the real/fouled system. The performance degradation is expressed using fouling factor (FF), which is derived from the overall heat transfer coefficient of design system and real system. It supports the system to improve the performance by asset utilization, energy efficient and cost reduction interms of production loss.

  18. An experimental and numerical study of a jetfire stop material and a new helical flow heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Austegard, Anders

    1997-12-31

    This thesis consists of two parts. Part 1: Experimental and numerical study of jetfire stop, and Part 2: Experimental and numerical study of a new kind of shell and tube heat exchanger with helical flow on shell side. Part 1 describes the development of the model for simulation of the temperature development through Viking jetfirestop. A simulation program is developed that calculates the temperature development through Viking jetfire stop. In the development of the model, measurements of reaction energy, pyrolysis and heat conductivity at low temperatures are made. The conductivity at higher temperatures and when pyrolysis reactions are going on is estimated experimentally and by numerical calculations. Full-scale jet fire test and small-scale xenon lamp experiments are made to test the simulation model. Part 2 contains the development of a model that simulate the fluid flow and heat transfer in a helical flow shell and tube heat exchanger. It consists of the development of a porosity model and a model for pressure drop and heat transfer as well as experiments in non-standard tube layouts. Results from the simulation program are compared with experiments on a helical flow shell and tube heat exchanger. There is a separate appendix volume. 62 refs., 152 figs., 22 tabs.

  19. Materials experience and selection for nuclear materials production reactor heat exchangers

    International Nuclear Information System (INIS)

    The primary coolant systems for the heavy-water nuclear materials production reactors at the Savannah River Site are coupled to the secondary coolant systems through shell and tube heat exchangers. The head, shell, and tube sheets of these heat exchangers are fabricated from AISI Type 304 grades of austenitic stainless steel. The 8,957 tubes in each heat exchanger were originally fabricated from Type 304 stainless steel, but service experience has lead to the use of Sea Cure tubing in newer systems. The design includes double tube sheets, core rods, and 33,410 square feet of heat transfer surface. Tubes are rolled into the tube sheets and seal welded after rolling. The tubes contain Type 304 stainless steel rods which are positioned in the center of each tube axis to increase the fraction of the cooling water contacting the heat transfer surface. Each reactor utilizes twelve heat exchangers; thus the 120+ reactor-years of operating experience provide approximately 1,440 heat exchanger-years of service. Fatigue, stress corrosion cracking, crevice corrosion, and pitting have been observed during the service life. This paper describes the observed degradation processes and uses the operational experience to recommend materials for the Heavy Water -- New Production Reactor (HW-NPR)

  20. Woven heat exchanger

    Science.gov (United States)

    Piscitella, R.R.

    1984-07-16

    This invention relates to a heat exchanger for waste heat recovery from high temperature industrial exhaust streams. In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.

  1. A Simple Tubesheet Layout Program for Heat Exchangers

    Directory of Open Access Journals (Sweden)

    S. Murali

    2008-01-01

    Full Text Available The development of tubesheet layout program for shell and tube heat exchangers is presented in this study. Program is written in AutoLISP language, which provides standard tubesheet layout drawing as per standard codes and non standard tubsheet in AutoCAD Environment. The program computes the optimal number of tube count and lays out drawing with respecting constraints, including the shell ID, number of passes, center to center distance of tubes and tube outer diameter. Tubesheet layout drawing can be used as template for actual tubesheet. Furthermore the program is validated with open literature and shown good agreement with it. Besides the tubesheet for Heat exchangers this method can be extended to the tube counts of sheave plates and perforated plates of distillation column and Cooling Towers.

  2. Optimasi Desain Heat Exchanger dengan Menggunakan Metode Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Rifnaldi Veriyawan

    2014-09-01

    Full Text Available Industri proses terutama perminyakan adalah salah satu industri membutuhkan energi panas dengan jumlah kapasitas besar. Dengan berjalan perkembangan teknologi dibutuhkannya proses perpindahan panas dalam jumlah besar. Tetapi dengan besarnya penukaran panas yang diberikan maka besar pula luas permukaan. Dibutuhkannya optimasi pada desain heat exchanger terutama shell-and-tube¬. Dalam tugas akhir ini, Algoritma particle swarm optimization (PSO digunakan untuk mengoptimasikan nilai koefesien perpindahan panas keseluruhan dengan mendapatkan nilai terbaik. Perumusan fungsi tujuan nilai perpindahan panas keseluruhan (U, dan luas permukaan (A yang digunakan untuk mencari nilai fungsi objektif pada PSO. Partikel dalam PSO menyatakan sebagai posisi atau solusi dari hasil optimasi didapatnya nilai perpindahan panas maksimal dengan luas permukaan dan pressure drop dibawah data desain atau datasheet. Partikel tersebut dalam pemodelan berupa rentang nilai minimal dan maksimal dari diameter luar diantara (do dan jumlah baffle (Nb. Dari hasil optimasi pada tiga HE didapatkan nilai U dan A secara berturut-turut; HE E-1111 472 W/m2C dan 289 m2 ;pada HE E-1107 174 W/m2C dan 265 m2 ; dan HE E-1102 618 W/m2C dan 574 m2. Nilai perpindahan panas keseluruhan yang telah dioptimasi sesuai dengan fungsi objektif dapat dikatakan HE shell-and-tube mencapai titik optimal.

  3. Parallel tube heat exchanger

    International Nuclear Information System (INIS)

    An improved heat exchanger for use in liquid metal cooled nuclear reactors, is described, which consists of a bundle of spaced, parallel tube assemblies for immersion in a primary heat exchange fluid. Each assembly defines flow and counterflow paths for a secondary heat exchange fluid in successive passes. Insulation reduces heat transfer between the flows of successive passes. (U.K.)

  4. Creep-fatigue damage evaluation of sodium to air heat exchanger in sodium test loop facility

    International Nuclear Information System (INIS)

    Highlights: ? A sodium test loop facility, STELLA, has two heat exchangers; AHX and DHX. ? Full 3D FE analyses for sodium-to-air heat exchanger (AHX) were performed. ? Stress levels at tubesheet joints based on full 3D analyses were not severe. ? Creep-fatigue damage was evaluated as per elevated temperature codes. ? ASME Section III Subsection NH was more conservative than RCC-MRx for AHX. - Abstract: A high temperature design and evaluation of creep-fatigue damage for a sodium-to-air heat exchanger, AHX, has been conducted according to the recent versions of the high temperature design codes based on a full three-dimensional finite element analysis. AHX is a shell- and tube-type heat exchanger with 36 helical tubes, and has an outer diameter of 1.59 m and height of 6.5 m. AHX was installed in a sodium test loop facility, STELLA (Sodium integral effect test loop for safety simulation and assessment) recently constructed at the KAERI site. The materials of the shell and tube in AHX are 304SS and 316SS, respectively. Evaluations of creep-fatigue damage based on 3D finite element analyses were conducted at several critical locations of AHX according to the recent elevated temperature design codes of ASME-NH and RCC-MR, and the evaluation results of the two codes were compared. Based on the high temperature damage evaluation, the AHX design has been finalized, and fabrication of the component was conducted.

  5. Appendix to the thesis an experimental and numerical study of a jetfire stop material and a new helical flow heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Austegard, Anders

    1997-12-31

    This thesis consists of two parts. Part 1: Experimental and numerical study of jetfire stop, and Part 2: Experimental and numerical study of a new kind of shell and tube heat exchanger with helical flow on shell side. Part 1 describes the development of the model for simulation of the temperature development through Viking jetfirestop. A simulation program is developed that calculates the temperature development through Viking jetfirestop. In the development of the model, measurements of reaction energy, pyrolysis and heat conductivity at low temperatures are made. The conductivity at higher temperatures and when pyrolysis reactions are going on is estimated experimentally and by numerical calculations. Full-scale jet fire test and small-scale xenon lamp experiments are made to test the simulation model. Part 2 contains the development of a model that simulate the fluid flow and heat transfer in a helical flow shell and tube heat exchanger. It consists of the development of a porosity model and a model for pressure drop and heat transfer as well as experiments in non-standard tube layouts. Results from the simulation program are compared with experiments on a helical flow shell and tube heat exchanger. This is a separate appendix volume, including computer codes and simulated results. 316 figs., 11 tabs.

  6. Studi Numerik Pengaruh Baffle Inclination Pada Alat Penukar Kalor Tipe Shell And Tube Terhadap Aliran Fluida Dan Perpindahan Panas

    Directory of Open Access Journals (Sweden)

    Rezky Fadil Arnaw

    2014-09-01

    Full Text Available Heat exchanger atau alat penukar kalor merupakan suatu peralatan yang digunakan untuk memindahkan sejumlah energi dalam bentuk panas dari satu fluida ke fluida yang lain. Perpindahan panas tersebut terjadi dari suatu fluida yang suhunya lebih tinggi ke fluida lain yang suhunya lebih rendah. Pada tugas akhir ini akan dilakukan penelitian tentang pengaruh baffle inclination terhadap aliran fluida dan perpindahan panas pada alat penukar kalor tipe shell and tube. Dalam penelitian ini akan dilakukan tiga variasi sudut baffle inclination yaitu 0º, 10° dan 20° dengan besar laju aliran massa yang divariasikan yaitu sebesar 0.5 kg/s, 1 kg/s dan 2 kg/s. Tipe baffle yang digunakan adalah single segmental baffle dengan baffle cut sebesar 36% dan menggunakan arah aliran jenis parallel. Hasil analisa simulasi menunjukkan bahwa laju aliran massa yang meningkat akan menyebabkan kenaikan pressure drop yang cukup drastis dan penurunan temperatur outlet. Alat penukar kalor dengan baffle inclination 0° memiliki nilai perpindahan panas terbaik jika dibandingkan dengan baffle inclination 10° dan 20°.

  7. Direct fired heat exchanger

    Science.gov (United States)

    Reimann, Robert C. (Lafayette, NY); Root, Richard A. (Spokane, WA)

    1986-01-01

    A gas-to-liquid heat exchanger system which transfers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine, to a liquid, generally an absorbent solution. The heat exchanger system is in a counterflow fluid arrangement which creates a more efficient heat transfer.

  8. Heat Exchanger Design Options and Tritium Transport Study for the VHTR System

    Energy Technology Data Exchange (ETDEWEB)

    Chang H. Oh; Eung S. Kim

    2008-09-01

    This report presents the results of a study conducted to consider heat exchanger options and tritium transport in a very high temperature reactor (VHTR) system for the Next Generation Nuclear Plant Project. The heat exchanger options include types, arrangements, channel patterns in printed circuit heat exchangers (PCHE), coolant flow direction, and pipe configuration in shell-and-tube designs. Study considerations include: three types of heat exchanger designs (PCHE, shell-and-tube, and helical coil); single- and two-stage unit arrangements; counter-current and cross flow configurations; and straight pipes and U-tube designs in shell-and-tube type heat exchangers. Thermal designs and simple stress analyses were performed to estimate the heat exchanger options, and the Finite Element Method was applied for more detailed calculations, especially for PCHE designs. Results of the options study show that the PCHE design has the smallest volume and heat transfer area, resulting in the least tritium permeation and greatest cost savings. It is theoretically the most reliable mechanically, leading to a longer lifetime. The two-stage heat exchanger arrangement appears to be safer and more cost effective. The recommended separation temperature between first and second stages in a serial configuration is 800oC, at which the high temperature unit is about one-half the size of the total heat exchanger core volume. Based on simplified stress analyses, the high temperature unit will need to be replaced two or three times during the plant’s lifetime. Stress analysis results recommend the off-set channel pattern configuration for the PCHE because stress reduction was estimated at up to 50% in this configuration, resulting in a longer lifetime. The tritium transport study resulted in the development of a tritium behavior analysis code using the MATLAB Simulink code. In parallel, the THYTAN code, previously performed by Ohashi and Sherman (2007) on the Peach Bottom data, was revived and verified. The 600 MWt VHTR core input file developed in preparation for the transient tritium analysis of VHTR systems was replaced with the original steady-state inputs for future calculations. A Finite Element Method analysis was performed using COMSOL Multiphysics software to accurately predict tritium permeation through the PCHE type heat exchanger walls. This effort was able to estimate the effective thickness for tritium permeations and develop a correlation for general channel configurations, which found the effective thickness to be much shorter than the average channel distance because of dead spots on the channel side.

  9. Dynamic friction modelling in heat exchanger tube simulations

    International Nuclear Information System (INIS)

    A force-balance friction model has been developed to describe dynamic friction phenomena in multi-degree of freedom vibration systems and validated for a two degree-of-freedom (2dof) lumped mass vibration system. It has been implemented into VIBIC, a finite element code for the vibration of beams with intermittent contact, to improve the prediction of tube wear rate in the simulation of shell-and-tube heat exchangers. The friction model has been tailored for VIBIC for various kinds of supports: circular, semi-circular scallop-bar, and arbitrary flat-bar supports. Simulations for single fuel pin vibration have been compared with experimental data on wear work rate for different test conditions, gaps and preloads

  10. Design of a Sulfur-trioxide Decomposer Exchanging Heat between N2 and Sulfuric-acid

    International Nuclear Information System (INIS)

    The High Temperature Gas Cooled Reactor (HTGR) with outlet coolant temperature up to 950 .deg. C is considered as an efficient reactor to be coupled with thermo-chemical SI(Sulfur Iodine) cycle for the hydrogen production. The small scale test loop of 10kW capacity was installed at Korea Atomic Energy Research Institute (KAERI) facility to confirm the integrity of the sulfur-trioxide decomposer, one of the key components, under actual HTGR operating conditions In this paper, the sulfur-trioxide decomposer was simulated with a chemical process simulator. A standard shell-and-tube heat exchanger model in the simulator was chosen for the simulation

  11. 46 CFR 59.10-20 - Patches in shells and tube sheets.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Patches in shells and tube sheets. 59.10-20 Section 59... § 59.10-20 Patches in shells and tube sheets. (a) Unreinforced openings in the shells or drums of... vessels are met. (b) Portions of tube sheets which have deteriorated may be renewed by replacing...

  12. Wound tube heat exchanger

    Science.gov (United States)

    Ecker, Amir L. (Duncanville, TX)

    1983-01-01

    What is disclosed is a wound tube heat exchanger in which a plurality of tubes having flattened areas are held contiguous adjacent flattened areas of tubes by a plurality of windings to give a double walled heat exchanger. The plurality of windings serve as a plurality of effective force vectors holding the conduits contiguous heat conducting walls of another conduit and result in highly efficient heat transfer. The resulting heat exchange bundle is economical and can be coiled into the desired shape. Also disclosed are specific embodiments such as the one in which the tubes are expanded against their windings after being coiled to insure highly efficient heat transfer.

  13. Microplate Heat Exchanger Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a microplate heat exchanger for cryogenic cooling systems used for continuous flow distributed cooling systems, large focal plane arrays, multiple...

  14. Optimization of Heat Exchangers

    International Nuclear Information System (INIS)

    The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics (pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger design.

  15. Optimization of Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Ivan Catton

    2010-10-01

    The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics )pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger disign.

  16. Nature's Heat Exchangers.

    Science.gov (United States)

    Barnes, George

    1991-01-01

    Discusses the heat-transfer systems of different animals. Systems include heat conduction into the ground, heat transferred by convection, heat exchange in lizards, fish and polar animals, the carotid rete system, electromagnetic radiation from animals and people, and plant and animal fiber optics. (MDH)

  17. High pressure ceramic heat exchanger. Phase I: deadhead experimental verification. [For externally fired gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    1979-02-20

    A recognized alternative for firing gas turbines with ash bearing fuels is the externally fired cycle. An essential component for such a cycle is a gas-to-gas heat exchanger capable of tolerating temperatures up to 2300/sup 0/F. Shell and tube heat exchangers having extended surface geometry have been developed for low pressure applications. Several units are presently in industrial service as air-preheaters for high temperature forge furnaces. The ability of the basic heat exchanger technology to withstand typical industrial gas turbine pressures was confirmed in the laboratory several years ago. In order to interest prospective manufacturers or users of the exhaust fired cycle, a pressure retention verification test emerged as an essential step. The execution and results of such an experiment are described.

  18. Active microchannel heat exchanger

    Science.gov (United States)

    Tonkovich, Anna Lee Y. (Pasco, WA) [Pasco, WA; Roberts, Gary L. (West Richland, WA) [West Richland, WA; Call, Charles J. (Pasco, WA) [Pasco, WA; Wegeng, Robert S. (Richland, WA) [Richland, WA; Wang, Yong (Richland, WA) [Richland, WA

    2001-01-01

    The present invention is an active microchannel heat exchanger with an active heat source and with microchannel architecture. The microchannel heat exchanger has (a) an exothermic reaction chamber; (b) an exhaust chamber; and (c) a heat exchanger chamber in thermal contact with the exhaust chamber, wherein (d) heat from the exothermic reaction chamber is convected by an exothermic reaction exhaust through the exhaust chamber and by conduction through a containment wall to the working fluid in the heat exchanger chamber thereby raising a temperature of the working fluid. The invention is particularly useful as a liquid fuel vaporizer and/or a steam generator for fuel cell power systems, and as a heat source for sustaining endothermic chemical reactions and initiating exothermic reactions.

  19. Evaluation of ORC modules performance adopting commercial plastic heat exchangers

    International Nuclear Information System (INIS)

    Highlights: • Application of plastic heat exchangers in Organic Rankine Cycle module. • Low temperature heat recovery. • Design of a 20 kW regenerative ORC adopting commercial plastic heat exchangers. • Electricity cost comparable with ORC modules with typical carbon steel components. • Economic benefit from plastic evaporator adoption with corrosive heat source media. - Abstract: In this paper the possible replacement of conventional metallic heat exchangers with plastic components is investigated with reference to low size Organic Rankine Cycles, aiming at a reduction of the plant investment cost. A thermodynamic optimization of a 20 kW regenerative ORC plant, representative of a low temperature (<140 °C) heat recovery application, has been carried out according to the presently available data for plastic shell and tubes heat exchangers offered on the market. N-heptane was selected as the working fluid, thanks to the capability to operate within the pressure limits for evaporation and condensation processes imposed by the adoption of plastic components. Finally, the potential economic benefit of the plastic solution in comparison with conventional heat exchangers made of carbon steel was evaluated for the whole plant; the case of enhanced materials adoption, which is mandatory for the evaporator in presence of corrosive heat source media, was also considered. It turns out that advantages of the proposed solution become appreciable whenever the presence of corrosive heat source media requires the use of materials other than carbon steel. For instance, for a plant availability of 5000 h/year and discount rate of 10%, we obtain a cost of the produced electricity of 94.8 $/MW h, 95.4 $/MW h, 101.5 $/MW h, and 118.9 $/MW h respectively for plastic, carbon steel, stainless steel and titanium solutions

  20. Heat exchangers: operation problems

    International Nuclear Information System (INIS)

    The main operation problems for heat exchangers are fouling, corrosion, vibrations and mechanical resistance. Fouling and corrosion lead to an over dimensioning, energy consumption increase, corroded pieces change, shutdown costs. Vibrations are taken in account during the dimensioning phase of the heat exchangers. Mechanical resistance problems are, for the classical ones, described in regulation texts. (A.B.). 5 figs., 4 tabs

  1. Heat and mass exchanger

    Science.gov (United States)

    Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc J. (Princeton, NJ); Miller, Jeffrey A. (Hopewell, NJ); Tonon, Thomas (Princeton, NJ)

    2011-06-28

    A mass and heat exchanger includes at least one first substrate with a surface for supporting a continuous flow of a liquid thereon that either absorbs, desorbs, evaporates or condenses one or more gaseous species from or to a surrounding gas; and at least one second substrate operatively associated with the first substrate. The second substrate includes a surface for supporting the continuous flow of the liquid thereon and is adapted to carry a heat exchange fluid therethrough, wherein heat transfer occurs between the liquid and the heat exchange fluid.

  2. Support for heat exchangers

    International Nuclear Information System (INIS)

    The very large heat exchangers which are typical of many nuclear power plants place great demands on their supports. The support here described is for a vertical heat exchanger. A convex Lubrit plate allows a certain amount of transverse and rotational movement of the heat exhanger relative to the foundation. Taps engaging in the support surface of the heat exchanger and between the support box and the concrete foundation ensure that relative movement is restricted to those surfaces where it is intended. A steel box structure embedded in the concrete foundation dissipates heat transferred through the support system and avoids overheating the concrete. Horizontal stays support the heat exchanger against the concrete walls. (JIW)

  3. Thermoelectric heat exchange element

    Science.gov (United States)

    Callas, James J. (Peoria, IL); Taher, Mahmoud A. (Peoria, IL)

    2007-08-14

    A thermoelectric heat exchange module includes a first substrate including a heat receptive side and a heat donative side and a series of undulatory pleats. The module may also include a thermoelectric material layer having a ZT value of 1.0 or more disposed on at least one of the heat receptive side and the heat donative side, and an electrical contact may be in electrical communication with the thermoelectric material layer.

  4. Damping in heat exchanger tube bundles. A review

    International Nuclear Information System (INIS)

    Damping is a major concern in the design and operation of tube bundles with loosely supported tubes in baffles for process shell and tube heat exchangers and steam generators which are used in nuclear, process and power generation industries. System damping has a strong influence on the amplitude of vibration. Damping depends upon the mechanical properties of the tube material, geometry of intermediate supports and the physical properties of shell-side fluid. Type of tube motion, number of supports, tube frequency, vibration amplitude, tube mass or diameter, side loads, support thickness, higher modes, shell-side temperature etc., affect damping in tube bundles. The importance of damping is further highlighted due to current trend of larger exchangers with increased shell-side velocities in modern units. Various damping mechanisms have been identified (Friction damping, Viscous damping, Squeeze film damping, Support damping. Two-Phase damping, and very recent-Thermal damping), which affect the performance of process exchangers and steam generators with respect to flow induced vibration design, including standard design guidelines. Damping in two-phase flow is very complex and highly void fraction, and flow-regime dependent. The current paper focuses on the various known damping mechanisms subjected to both single and two-phase cross-flow in process heat exchangers and steam generators and formulates the design guidelines for safer design. (author)

  5. Overall heat transfer coefficient and pressure drop in a typical tubular exchanger employing alumina nano-fluid as the tube side hot fluid

    Science.gov (United States)

    Kabeel, A. E.; Abdelgaied, Mohamed

    2015-08-01

    Nano-fluids are used to improve the heat transfer rates in heat exchangers, especially; the shell-and-tube heat exchanger that is considered one of the most important types of heat exchangers. In the present study, an experimental loop is constructed to study the thermal characteristics of the shell-and-tube heat exchanger; at different concentrations of Al2O3 nonmetallic particles (0.0, 2, 4, and 6 %). This material concentrations is by volume concentrations in pure water as a base fluid. The effects of nano-fluid concentrations on the performance of shell and tube heat exchanger have been conducted based on the overall heat transfer coefficient, the friction factor, the pressure drop in tube side, and the entropy generation rate. The experimental results show that; the highest heat transfer coefficient is obtained at a nano-fluid concentration of 4 % of the shell side. In shell side the maximum percentage increase in the overall heat transfer coefficient has reached 29.8 % for a nano-fluid concentration of 4 %, relative to the case of the base fluid (water) at the same tube side Reynolds number. However; in the tube side the maximum relative increase in pressure drop has recorded the values of 12, 28 and 48 % for a nano-material concentration of 2, 4 and 6 %, respectively, relative to the case without nano-fluid, at an approximate value of 56,000 for Reynolds number. The entropy generation reduces with increasing the nonmetallic particle volume fraction of the same flow rates. For increase the nonmetallic particle volume fraction from 0.0 to 6 % the rate of entropy generation decrease by 10 %.

  6. Heat exchanger design handbook

    CERN Document Server

    Thulukkanam, Kuppan

    2013-01-01

    Completely revised and updated to reflect current advances in heat exchanger technology, Heat Exchanger Design Handbook, Second Edition includes enhanced figures and thermal effectiveness charts, tables, new chapter, and additional topics--all while keeping the qualities that made the first edition a centerpiece of information for practicing engineers, research, engineers, academicians, designers, and manufacturers involved in heat exchange between two or more fluids.See What's New in the Second Edition: Updated information on pressure vessel codes, manufacturer's association standards A new c

  7. Plate-Type Heat Exchanger

    International Science & Technology Center (ISTC)

    Conduction of Experimental Studies of Heat Exchange Element of Plate-Type Heat Exchanger Aiming at Enhancement of its Effectiveness Owing to Design Improvement and Optimization of Used Heat Exchange Intensifiers

  8. Microtube Strip Heat Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Doty, F.D.

    1990-12-27

    Doty Scientific (DSI) believes their Microtube-Strip Heat Exchanger will contribute significantly to (a) the closed Brayton cycles being pursued at MIT, NASA, and elsewhere; (b) reverse Brayton cycle cryocoolers, currently being investigated by NASA for space missions, being applied to MRI superconducting magnets; and (c) high-efficiency cryogenic gas separation schemes for CO{sub 2} removal from exhaust stacks. The goal of this current study is to show the potential for substantial progress in high-effectiveness, low-cost, gas-to-gas heat exchangers for diverse applications at temperatures from below 100 K to above 1000 K. To date, the highest effectiveness measured is about 98%, and relative pressure drops below 0.1% with a specific conductance of about 45 W/kgK are reported. During the pre-award period DSI built and tested a 3-module heat exchanger bank using 103-tube microtube strip (MTS) modules. To add to their analytical capabilities, DSI has acquired computational fluid dynamics (CFD) software. This report describes the pre-award work and the status of the ten tasks of the current project, which are: analyze flow distribution and thermal stresses within individual modules; design a heat exchanger bank of ten modules with 400 microtube per module; obtain production quality tubestrip die and AISI 304 tubestrips; obtain production quality microtubing; construct revised MTS heat exchanger; construct dies and fixtures for prototype heat exchanger; construct 100 MTS modules; assemble 8-10 prototype MTS heat exchangers; test prototype MTS heat exchanger; and verify test through independent means. 7 refs., 9 figs. 1 tab. (CK)

  9. Microtube strip heat exchanger

    Science.gov (United States)

    Doty, F. D.

    1990-12-01

    Doty Scientific (DSI) believes their microtube-strip heat exchanger will contribute significantly to the following: (1) the closed Brayton cycles being pursued at MIT, NASA, and elsewhere; (2) reverse Brayton cycle cryocoolers, currently being investigated by NASA for space missions, being applied to MRI superconducting magnets; and (3) high-efficiency cryogenic gas separation schemes for CO2 removal from exhaust stacks. The goal of this current study is to show the potential for substantial progress in high-effectiveness, low-cost, gas-to-gas heat exchangers for diverse applications at temperatures from below 100 K to above 1000 K. To date, the highest effectiveness measured is about 98 percent and relative pressure drops below 0.1 percent with a specific conductance of about 45 W/kgK are reported. During the pre-award period DSI built and tested a 3-module heat exchanger bank using 103-tube microtube strip (MTS) modules. To add to their analytical capabilities, DSI has acquired computational fluid dynamics (CFD) software. This report describes the pre-award work and the status of the ten tasks of the current project, which are: analyze flow distribution and thermal stresses within individual modules; design a heat exchanger bank of ten modules with 400 microtube per module; obtain production quality tubestrip die and AISI 304 tubestrips; obtain production quality microtubing; construct revised MTS heat exchanger; construct dies and fixtures for prototype heat exchanger; construct 100 MTS modules; assemble 8 to 10 prototype MTS heat exchangers; test prototype MTS heat exchanger; and verify test through independent means.

  10. Radial flow heat exchanger

    Science.gov (United States)

    Valenzuela, Javier (Hanover, NH)

    2001-01-01

    A radial flow heat exchanger (20) having a plurality of first passages (24) for transporting a first fluid (25) and a plurality of second passages (26) for transporting a second fluid (27). The first and second passages are arranged in stacked, alternating relationship, are separated from one another by relatively thin plates (30) and (32), and surround a central axis (22). The thickness of the first and second passages are selected so that the first and second fluids, respectively, are transported with laminar flow through the passages. To enhance thermal energy transfer between first and second passages, the latter are arranged so each first passage is in thermal communication with an associated second passage along substantially its entire length, and vice versa with respect to the second passages. The heat exchangers may be stacked to achieve a modular heat exchange assembly (300). Certain heat exchangers in the assembly may be designed slightly differently than other heat exchangers to address changes in fluid properties during transport through the heat exchanger, so as to enhance overall thermal effectiveness of the assembly.

  11. Counterflow Regolith Heat Exchanger

    Science.gov (United States)

    Zubrin, Robert; Jonscher, Peter

    2013-01-01

    A problem exists in reducing the total heating power required to extract oxygen from lunar regolith. All such processes require heating a great deal of soil, and the heat energy is wasted if it cannot be recycled from processed material back into new material. The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat exchanger with internal and external augers attached to the inner rotating tube to move the regolith. Hot regolith in the outer tube is moved in one direction by a right-hand - ed auger, and the cool regolith in the inner tube is moved in the opposite direction by a left-handed auger attached to the inside of the rotating tube. In this counterflow arrangement, a large fraction of the heat from the expended regolith is transferred to the new regolith. The spent regolith leaves the heat exchanger close to the temperature of the cold new regolith, and the new regolith is pre-heated close to the initial temperature of the spent regolith. Using the CoRHE can reduce the heating requirement of a lunar ISRU system by 80%, reducing the total power consumption by a factor of two. The unique feature of this system is that it allows for counterflow heat exchange to occur between solids, instead of liquids or gases, as is commonly done. In addition, in variants of this concept, the hydrogen reduction can be made to occur within the counterflow heat exchanger itself, enabling a simplified lunar ISRU (in situ resource utilization) system with excellent energy economy and continuous nonbatch mode operation.

  12. Development of multi-dimensional thermal hydraulic analysis code AMADEUS for intermediate heat exchanger and hydraulic modeling in crossflow field

    International Nuclear Information System (INIS)

    A multi-dimensional thermal hydraulic analysis code AMADEUS has been developed for the shell-and-tube type Intermediate Heat Exchanger (IHX) of Fast Breeder Reactor. The code was characterized with incorporating an advanced porous body model: the dynamic porous body model taking into consideration the recirculating flow region behind the tubes to enhance accuracy in simulating momentum and pressure field. The advantage of the dynamic porous body model was demonstrated through the comparison between experiments and calculations. And it was indicated that the dynamic porous body model was applicable to the detailed assessment of the IHX thermal hydraulic design. (author)

  13. Method to design shell-side pressure drop constrained tubular heat exchangers

    International Nuclear Information System (INIS)

    In shell and tube heat exchangers, the triple segmental baffle arrangement has been infrequently used, even though the potential of this baffle system for high thermal effectiveness with low pressure drop is generally known. This neglect seems to stem from the lack of published design guidelines on the subject. Lately, however, with the rapid growth in the size of nuclear heat exchangers, the need to develop unconventional baffling pattern has become increasingly important. A method to utilize effectively the triple segmental concept to develop economical designs is presented herein. The solution technique given in this paper is based on a flow model named ''Piecewise Continuous Cosine Model.'' The solution procedure easily lends itself to detailed analysis to determine safety against flow-induced vibrations. 20 refs

  14. Vibration damping of heat exchanger tube bundles in two-phase flow

    International Nuclear Information System (INIS)

    Two-phase flow exists in many shell-and-tube heat exchangers such as condensers, evaporators and nuclear steam generators. To avoid flow-induced vibration problems, it is necessary to have some information on tube damping mechanisms. This report pertains to the development of a model to formulate damping in two-phase cross-flow. This formulation is based on information available in the literature and particularly on the results of a recently completed experimental program. The compilation of a data base, the development of a semi-empirical model and the formulation of design guidelines are discussed in this report. The calculation of heat exchanger tube damping in two-phase cross-flow is illustrated by an example

  15. Microtube strip heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Doty, F.D.

    1992-07-09

    The purpose of this contract has been to explore the limits of miniaturization of heat exchangers with the goals of (1) improving the theoretical understanding of laminar heat exchangers, (2) evaluating various manufacturing difficulties, and (3) identifying major applications for the technology. A low-cost, ultra-compact heat exchanger could have an enormous impact on industry in the areas of cryocoolers and energy conversion. Compact cryocoolers based on the reverse Brayton cycle (RBC) would become practical with the availability of compact heat exchangers. Many experts believe that hardware advances in personal computer technology will rapidly slow down in four to six years unless lowcost, portable cryocoolers suitable for the desktop supercomputer can be developed. Compact refrigeration systems would permit dramatic advances in high-performance computer work stations with conventional'' microprocessors operating at 150 K, and especially with low-cost cryocoolers below 77 K. NASA has also expressed strong interest in our MTS exchanger for space-based RBC cryocoolers for sensor cooling. We have demonstrated feasibility of higher specific conductance by a factor of five than any other work in high-temperature gas-to-gas exchangers. These laminar-flow, microtube exchangers exhibit extremely low pressure drop compared to alternative compact designs under similar conditions because of their much shorter flow length and larger total flow area for lower flow velocities. The design appears to be amenable to mass production techniques, but considerable process development remains. The reduction in materials usage and the improved heat exchanger performance promise to be of enormous significance in advanced engine designs and in cryogenics.

  16. Microtube strip heat exchanger

    Science.gov (United States)

    Doty, F. D.

    1992-07-01

    The purpose of this contract has been to explore the limits of miniaturization of heat exchangers with the goals of (1) improving the theoretical understanding of laminar heat exchangers, (2) evaluating various manufacturing difficulties, and (3) identifying major applications for the technology. A low-cost, ultra-compact heat exchanger could have an enormous impact on industry in the areas of cryocoolers and energy conversion. Compact cryocoolers based on the reverse Brayton cycle (RBC) would become practical with the availability of compact heat exchangers. Many experts believe that hardware advances in personal computer technology will rapidly slow down in four to six years unless lowcost, portable cryocoolers suitable for the desktop supercomputer can be developed. Compact refrigeration systems would permit dramatic advances in high-performance computer work stations with 'conventional' microprocessors operating at 150 K, and especially with low-cost cryocoolers below 77 K. NASA has also expressed strong interest in our MTS exchanger for space-based RBC cryocoolers for sensor cooling. We have demonstrated feasibility of higher specific conductance by a factor of five than any other work in high-temperature gas-to-gas exchangers. These laminar-flow, microtube exchangers exhibit extremely low pressure drop compared to alternative compact designs under similar conditions because of their much shorter flow length and larger total flow area for lower flow velocities. The design appears to be amenable to mass production techniques, but considerable process development remains. The reduction in materials usage and the improved heat exchanger performance promise to be of enormous significance in advanced engine designs and in cryogenics.

  17. Monogroove liquid heat exchanger

    Science.gov (United States)

    Brown, Richard F. (Inventor); Edelstein, Fred (Inventor)

    1990-01-01

    A liquid supply control is disclosed for a heat transfer system which transports heat by liquid-vapor phase change of a working fluid. An assembly (10) of monogroove heat pipe legs (15) can be operated automatically as either heat acquisition devices or heat discharge sources. The liquid channels (27) of the heat pipe legs (15) are connected to a reservoir (35) which is filled and drained by respective filling and draining valves (30, 32). Information from liquid level sensors (50, 51) on the reservoir (35) is combined (60) with temperature information (55) from the liquid heat exchanger (12) and temperature information (56) from the assembly vapor conduit (42) to regulate filling and draining of the reservoir (35), so that the reservoir (35) in turn serves the liquid supply/drain needs of the heat pipe legs (15), on demand, by passive capillary action (20, 28).

  18. Heat exchanger restart evaluation

    International Nuclear Information System (INIS)

    On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4kA was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summarized herein

  19. Preliminary Evaluation of PGSFR DHR Heat Exchangers Performance Using STELLA-1 Facility

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jonggan; Eoh, Jae-Hyuk; Yeom, Sujin; Lee, Jewhan; Kim, Tae-Joon; Hwang, Inkoo; Cho, Chungho; Kim, Jong-Man; Cho, Youngil; Jung, Min-Hwan; Gam, Da-Young; Jeong, Ji-Young [Korean Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The STELLA program for PGSFR decay heat removal (DHR) performance demonstration is in progress at KAERI. As the first phase of the program, the STELLA-1 facility has been constructed and separate effect tests for heat exchangers of DHRS have been conducted. Two kinds of heat exchangers including a shell-and-tube type sodium-to-sodium heat exchanger (DHX) and a helical-tube type sodium-to-air heat exchanger (AHX) were tested for design codes V-V, e.g. SHXSA and AHXSA. In this paper, firstly, overall characteristics of the STELLA-1 facility are described briefly. Secondly, the performance tests of the DHX and AHX rely on a steady-state result of a heat transfer experiment. Thus experimental procedures to obtain the steady-state result are described and steady-state conditions for the heat exchanger performance test are clearly defined. Lastly, experimental results and calculation results obtained from the design codes are also compared as a preliminary work for the design code V-V. The PGSFR DHR heat exchangers performance was experimentally demonstrated using the STELLA-1 facility, and the experimental results and the prediction of the design code were compared as a preliminary work for the design code V-V. The experimental results of the DHX and AHX were in good agreement with the estimation of the SHXSA and AHXSA codes, respectively.

  20. Modular heat exchanger

    International Nuclear Information System (INIS)

    A heat exchanger for use in nuclear reactors is disclosed which includes a heat exchange tube bundle formed from similiar modules each having a hexagonal shroud containing a large number of thermally conductive tubes which are connected with inlet and outlet headers at opposite ends of each module, the respective headers being adapted for interconnection with suitable inlet and outlet manifold means. In order to adapt the heat exchanger for operation in a high temperature and high pressure environment and to provide access to all tube ports at opposite ends of the tube bundle, a spherical tube sheet is arranged in sealed relation across the chamber with an elongated duct extending outwardly therefrom to provide manifold means for interconnection with the opposite end of the tube bundle

  1. Creep-fatigue damage evaluation of sodium to air heat exchanger in sodium test loop facility

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeong-Yeon, E-mail: hylee@kaeri.re.kr [Korea Atomic Energy Research Institute, Deadeok-daero 989-111, Yusong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Jong-Bum [Korea Atomic Energy Research Institute, Deadeok-daero 989-111, Yusong-gu, Daejeon 305-353 (Korea, Republic of); Park, Hong-Yune [AD-Solution Co., Ltd., 1101 Hanjin Officetel 535-5, Bongmyoung-dong Yusong-gu, Daejeon 305-301 (Korea, Republic of)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer A sodium test loop facility, STELLA, has two heat exchangers; AHX and DHX. Black-Right-Pointing-Pointer Full 3D FE analyses for sodium-to-air heat exchanger (AHX) were performed. Black-Right-Pointing-Pointer Stress levels at tubesheet joints based on full 3D analyses were not severe. Black-Right-Pointing-Pointer Creep-fatigue damage was evaluated as per elevated temperature codes. Black-Right-Pointing-Pointer ASME Section III Subsection NH was more conservative than RCC-MRx for AHX. - Abstract: A high temperature design and evaluation of creep-fatigue damage for a sodium-to-air heat exchanger, AHX, has been conducted according to the recent versions of the high temperature design codes based on a full three-dimensional finite element analysis. AHX is a shell- and tube-type heat exchanger with 36 helical tubes, and has an outer diameter of 1.59 m and height of 6.5 m. AHX was installed in a sodium test loop facility, STELLA (Sodium integral effect test loop for safety simulation and assessment) recently constructed at the KAERI site. The materials of the shell and tube in AHX are 304SS and 316SS, respectively. Evaluations of creep-fatigue damage based on 3D finite element analyses were conducted at several critical locations of AHX according to the recent elevated temperature design codes of ASME-NH and RCC-MR, and the evaluation results of the two codes were compared. Based on the high temperature damage evaluation, the AHX design has been finalized, and fabrication of the component was conducted.

  2. Tube vibration in industrial size test heat exchanger

    International Nuclear Information System (INIS)

    Tube vibration data from tests of a specially built and instrumented, industrial-type, shell-and-tube heat exchanger are reported. The heat exchanger is nominally 0.6 m (2 ft) in dia and 3.7 m (12 ft) long. Both full tube and no-tubes-in-window bundles were tested for inlet/outlet nozzles of different sizes and with the tubes supported by seven, equally-spaced, single-segmental baffles. Prior to water flow testing, natural frequencies and damping of representative tubes were measured in air and water. Flow testing was accomplished by increasing the flow rates in stepwise fashion and also by sweeping through a selected range of flow rates. The primary variables measured and reported are tube accelerations and/or displacements and pressure drop through the bundle. Tests of the full tube bundle configuration revealed tube rattling to occur at intermediate flow rates, and fluidelastic instability, with resultant tube impacting, to occur when the flow rate exceeded a threshold level; principally, the four-span tubes were involved in the regions immediately adjacent to the baffle cut. For the range of flow rates tested, fluidelastic instability was not achieved in the no-tubes-in-window bundle; in this configuration the tubes are supported by all seven baffles and are, therefore, stiffer

  3. Tube boiler heat exchanger

    International Nuclear Information System (INIS)

    The tube boiler heat exchanger has been designed for use in a steam generator circuit of a sodium cooled fast breeder reactor. U-type heat exchanger tubes with legs of different lengths are suspended within the boiler. They are made of steel with 9% chrome content. Each tube is passed through an opening in the tube wall with some clearance and then tightly sealed to the tube wall by means of a sleeve. This seal is achieved by a brazed connection using Nicrobraz 135 brazing metal (nickel base alloy) applied by means of a high frequency induction technique. (GL/DG)

  4. Heat exchange apparatus

    Science.gov (United States)

    Degtiarenko, Pavel V.

    2003-08-12

    A heat exchange apparatus comprising a coolant conduit or heat sink having attached to its surface a first radial array of spaced-apart parallel plate fins or needles and a second radial array of spaced-apart parallel plate fins or needles thermally coupled to a body to be cooled and meshed with, but not contacting the first radial array of spaced-apart parallel plate fins or needles.

  5. Robust multi-objective optimization of state feedback controllers for heat exchanger system with probabilistic uncertainty

    Science.gov (United States)

    Lotfi, Babak; Wang, Qiuwang

    2013-07-01

    The performance of thermal control systems has, in recent years, improved in numerous ways due to developments in control theory and information technology. The shell-and-tube heat exchanger (STHX) is a medium where heat transfer process occurred. The accuracy of the heat exchanger depends on the performance of both elements. Therefore, both components need to be controlled in order to achieve a substantial result in the process. For this purpose, the actual dynamics of both shell and tube of the heat exchanger is crucial. In this paper, optimal reliability-based multi-objective Pareto design of robust state feedback controllers for a STHX having parameters with probabilistic uncertainties. Accordingly, the probabilities of failure of those objective functions are also considered in the reliability-based design optimization (RBDO) approach. A new multi-objective uniform-diversity genetic algorithm (MUGA) is presented and used for Pareto optimum design of linear state feedback controllers for STHX problem. In this way, Pareto front of optimum controllers is first obtained for the nominal deterministic STHX using the conflicting objective functions in time domain. Such Pareto front is then obtained for STHX having probabilistic uncertainties in its parameters using the statistical moments of those objective functions through a Hammersley Sequence Sampling (HSS) approach. It is shown that multi-objective reliability-based Pareto optimization of the robust state feedback controllers using MUGA includes those that may be obtained by various crisp threshold values of probability of failures and, thus, remove the difficulty of selecting suitable crisp values. Besides, the multi-objective Pareto optimization of such robust feedback controllers using MUGA unveils some very important and informative trade-offs among those objective functions. Consequently, some optimum robust state feedback controllers can be compromisingly chosen from the Pareto frontiers.

  6. A minichannel aluminium tube heat exchanger - Pt. 1: Evaluation of single-phase heat transfer coefficients by the Wilson plot method

    Energy Technology Data Exchange (ETDEWEB)

    Fernando, Primal; Palm, Bjoern; Ameel, Tim; Lundqvist, Per; Granryd, Eric [Department of Energy Technology, Division of Applied Thermodynamics and Refrigeration, Royal Institute of Technology (KTH), Stockholm (Sweden)

    2008-06-15

    A prototype liquid-to-refrigerant heat exchanger was developed with the aim of minimizing the refrigerant charge in small systems. To allow correct calculation of the refrigerant side heat transfer, the heat exchanger was first tested for liquid-to-liquid (water-to-water) operation in order to determine the single-phase heat transfer performance. These single-phase tests are reported in this paper. The heat exchanger was made from extruded multiport aluminium tubes and was designed similar to a shell-and-tube heat exchanger. The heat transfer areas of the shell-side and tube-side were approximately 0.82 m{sup 2} and 0.78 m{sup 2}, respectively. There were six rectangular-shaped parallel channels in a tube. The hydraulic diameter of the tube-side was 1.42 mm and of the shell-side 3.62 mm. Tests were conducted with varying water flow rates, temperature levels and heat fluxes on both the tube and shell sides at Reynolds numbers of approximately 170-6000 on the tube-side and 1000-5000 on the shell-side, respectively. The Wilson plot method was employed to investigate the heat transfer on both the shell and tube sides. In the Reynolds number range of 2300-6000, it was found that the Nusselt numbers agreed with those predicted by the Gnielinski correlation within {+-}5% accuracy. In the Reynolds number range of 170-1200 the Nusselt numbers gradually increased from 2.1 to 3.7. None of the previously reported correlations for laminar flow predicted the Nusselt numbers well in this range. The shell-side Nusselt numbers were found to be considerably higher than those predicted by correlations from the literature. (author)

  7. Double barrier heat exchanger

    International Nuclear Information System (INIS)

    This invention concerns a double barrier heat exchanger, between a radioactive primary fluid and a secondary fluid, enabling a possible leak of primary fluid in the exchanger to be detected in particular. As the primary fluid flows through a primary ducting and the secondary fluid through a secondary ducting, a joint matrix is placed between the primary and secondary ductings and in contact with them. The matrix includes at least on element, for example silver, able to be made radioactive when it diffuses in the primary fluid which carries it to an activation source. The application concerns sampling systems of water cooled nuclear reactors

  8. Electrostatic enhancement of heat transfer in gas-to-gas heat exchangers. Final report, June 1987-March 1991

    Energy Technology Data Exchange (ETDEWEB)

    Ohadi, M.M.

    1991-06-01

    Basic study of electrohydrodynamic (EHD) enhancement of heat transfer in heat exchangers has been the subject of an experimental investigation in the project. The authors efforts over the three-year project time period can be categorized into three consecutive phases. In phase I, EHD heat transfer enhancements and pressure drop characteristics for conventional pipe flows as a function of electric field potential, field polarity and number of electrodes (single or double configurations), and flow regime (Reynolds number ranging from fully laminar to fully turbulent conditions) were studied. Study of heat transfer enhancements and pressure drop characteristics in a shell-and-tube, gas-to-gas heat exchanger were performed in Phase II of the project. To address the applicability of EHD technique under operating conditions of gas-fired equipment, the role of various working fluid properties were studied in Phase III of the project. Specifically, effects of working fluid humidity, temperature, pressure, and impurity level on magnitude and nature of the EHD heat transfer enhancements were studied. A maximum of 322% heat transfer enhancement with only 112% increase in pressure drops was achieved under simultaneous excitation of the tube and shell sides of the heat exchanger in the study. With optimized electric and flow field parameters much higher enhancements can be expected.

  9. Electrostatic enhancement of heat transfer in a gas-to-gas heat exchanger. Final report, July 1991-June 1992

    Energy Technology Data Exchange (ETDEWEB)

    Ohadi, M.M.; Ansari, A.I.

    1992-07-01

    This is the final report on the last phase of a four-year GRI-sponsored experimental effort on heat transfer enhancement in gas-to-gas heat exchangers utilizing the electrostatic (or electrohydrodynamic, EHD) technique. The feasibility of the technique and the role of various controlling parameters for basic pipe flows and in a double-pipe heat exchanger were addressed in the first three phases of the project. In the current, and last, phase the feasibility of the electrostatic technique as a compound heat transfer augmentation methodology and its use in multi-tube heat exchangers was investigated. The compound enhancement experiments were performed on a commercially available finned tube by performing experiments on a micro-finned tube in the presence of electric field. Next, to address some of the practical problems that may be associated with the EHD technique, a multi-tube shell-and-tube heat exchanger was designed, fabricated, and experimentally tested. It is demonstrated that the EHD effect when used in conjunction with a low-fin or enhanced tube can yield additional enhancements to the already enhanced configuration as much as 80% in the present experiments technique.

  10. ASME code considerations for the compact heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Nestell, James [MPR Associates Inc., Alexandria, VA (United States); Sham, Sam [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-31

    The mission of the U.S. Department of Energy (DOE), Office of Nuclear Energy is to advance nuclear power in order to meet the nation's energy, environmental, and energy security needs. Advanced high temperature reactor systems such as sodium fast reactors and high and very high temperature gas-cooled reactors are being considered for the next generation of nuclear reactor plant designs. The coolants for these high temperature reactor systems include liquid sodium and helium gas. Supercritical carbon dioxide (sCO₂), a fluid at a temperature and pressure above the supercritical point of CO₂, is currently being investigated by DOE as a working fluid for a nuclear or fossil-heated recompression closed Brayton cycle energy conversion system that operates at 550°C (1022°F) at 200 bar (2900 psi). Higher operating temperatures are envisioned in future developments. All of these design concepts require a highly effective heat exchanger that transfers heat from the nuclear or chemical reactor to the chemical process fluid or the to the power cycle. In the nuclear designs described above, heat is transferred from the primary to the secondary loop via an intermediate heat exchanger (IHX) and then from the intermediate loop to either a working process or a power cycle via a secondary heat exchanger (SHX). The IHX is a component in the primary coolant loop which will be classified as "safety related." The intermediate loop will likely be classified as "not safety related but important to safety." These safety classifications have a direct bearing on heat exchanger design approaches for the IHX and SHX. The very high temperatures being considered for the VHTR will require the use of very high temperature alloys for the IHX and SHX. Material cost considerations alone will dictate that the IHX and SHX be highly effective; that is, provide high heat transfer area in a small volume. This feature must be accompanied by low pressure drop and mechanical reliability and robustness. Classic shell and tube designs will be large and costly, and may only be appropriate in steam generator service in the SHX where boiling inside the tubes occurs. For other energy conversion systems, all of these features can be met in a compact heat exchanger design. This report will examine some of the ASME Code issues that will need to be addressed to allow use of a Code-qualified compact heat exchanger in IHX or SHX nuclear service. Most effort will focus on the IHX, since the safety-related (Class A) design rules are more extensive than those for important-to-safety (Class B) or commercial rules that are relevant to the SHX.

  11. Manufacture of heat exchangers

    International Nuclear Information System (INIS)

    A tube bundle for use in a heat exchanger has a series of spaced parallel tubes supported by tube plates and is manufactured by depositing welding material around the end of each tube, machining the deposited material to form an annular flange around the end of the tube and welding the flange into apertures in the tube plate. Preferably the tubes have a length which is slightly less than the distance between the outer surfaces of the tube plates and the deposited material is deposited so that it overlaps and protects the end surfaces of the tubes. A plug may be inserted in the bore of the tubes during the welding material deposition which, as described, is effected by manual metal arc welding. One use of heat exchangers incorporating a tube bundle manufactured as above is in apparatus for reducing the volume of, and recovering nitric acid from, radioactive effluents from a nuclear reprocessing plant. (author)

  12. Tubed heat exchanger

    International Nuclear Information System (INIS)

    A tubed heat exchanger is described, which has at least one tube with transverse flow over it. The invention concerns the improvement of efficiency by avoiding thick boundary layers on the tube. It has transverse ribs set on it with special projections, which, according to the invention lie only on one side of the main plane of the ribs. Eight pictures illustrate the proposal. (RW)

  13. Heat exchanger tube tool

    International Nuclear Information System (INIS)

    Certain types of heat-exchangers have tubes opening through a tube sheet to a manifold having an access opening offset from alignment with the tube ends. A tool for inserting a device, such as for inspection or repair, is provided for use in such instances. The tool is formed by a flexible guide tube insertable through the access opening and having an inner end provided with a connector for connection with the opening of the tube in which the device is to be inserted, and an outer end which remains outside of the chamber, the guide tube having adequate length for this arrangement. A flexible transport hose for internally transporting the device slides inside of the guide tube. This hose is long enough to slide through the guide tube, into the heat-exchanger tube, and through the latter to the extent required for the use of the device. The guide tube must be bent to reach the end of the heat-exchanger tube and the latter may be constructed with a bend, the hose carrying anit-friction elements at interspaced locations along its length to make it possible for the hose to negotiate such bends while sliding to the location where the use of the device is required

  14. A chaotic quantum-behaved particle swarm approach applied to optimization of heat exchangers

    International Nuclear Information System (INIS)

    Particle swarm optimization (PSO) method is a population-based optimization technique of swarm intelligence field in which each solution called “particle” flies around in a multidimensional problem search space. During the flight, every particle adjusts its position according to its own experience, as well as the experience of neighboring particles, using the best position encountered by itself and its neighbors. In this paper, a new quantum particle swarm optimization (QPSO) approach combined with Zaslavskii chaotic map sequences (QPSOZ) to shell and tube heat exchanger optimization is presented based on the minimization from economic view point. The results obtained in this paper for two case studies using the proposed QPSOZ approach, are compared with those obtained by using genetic algorithm, PSO and classical QPSO showing the best performance of QPSOZ. In order to verify the capability of the proposed method, two case studies are also presented showing that significant cost reductions are feasible with respect to traditionally designed exchangers. Referring to the literature test cases, reduction of capital investment up to 20% and 6% for the first and second cases, respectively, were obtained. Therefore, the annual pumping cost decreased markedly 72% and 75%, with an overall decrease of total cost up to 30% and 27%, respectively, for the cases 1 and 2, respectively, showing the improvement potential of the proposed method, QPSOZ. - Highlights: ? Shell and tube heat exchanger is minimized from economic view point. ? A new quantum particle swarm optimization (QPSO) combined with Zaslavskii chaotic map sequences (QPSOZ) is proposed. ? Reduction of capital investment up to 20% and 6% for the first and second cases was obtained. ? Annual pumping cost decreased 72% and 75%, with an overall decrease of total cost up to 30% and 27% using QPSOZ.

  15. A minichannel aluminium tube heat exchanger - Pt. 3: Condenser performance with propane

    Energy Technology Data Exchange (ETDEWEB)

    Fernando, Primal; Palm, Bjoern; Ameel, Tim; Lundqvist, Per; Granryd, Eric [Department of Energy Technology, Division of Applied Thermodynamics and Refrigeration, Royal Institute of Technology (KTH), Stockholm (Sweden)

    2008-06-15

    This paper reports heat transfer results obtained during condensation of refrigerant propane inside a minichannel aluminium heat exchanger vertically mounted in an experimental setup simulating a water-to-water heat pump. The condenser was constructed of multiport minichannel aluminium tubes assembled as a shell-and-tube heat exchanger. Propane vapour entered the condenser tubes via the top end and exited sub-cooled from the bottom. Coolant water flowed upward on the shell-side. The heat transfer areas of the tube-side and the shell-side of the condenser were 0.941 m{sup 2} and 0.985 m{sup 2}, respectively. The heat transfer rate between the two fluids was controlled by varying the evaporation temperature while the condensation temperature was fixed. The applied heat transfer rate was within 3900-9500 W for all tests. Experiments were performed at constant condensing temperatures of 30{sup o}C, 40{sup o}C and 50{sup o}C, respectively. The cooling water flow rate was maintained at 11.90 l min{sup -1} for all tests. De-superheating length, two-phase length, sub-cooling length, local heat transfer coefficients and average heat transfer coefficients of the condenser were calculated. The experimental heat transfer coefficients were compared with predictions from correlations found in the literature. The experimental heat transfer coefficients in the different regions were higher than those predicted by the available correlations. (author)

  16. Experimental investigation on performances of trisection helical baffled heat exchangers for oil/water–water heat transfer

    International Nuclear Information System (INIS)

    Highlights: • Oil/water–water heat transfer performance tests of different schemes were conducted. • 12–28° incline angled helical baffle heat exchangers and segment one were studied. • Smaller incline angle is, higher are the shell side ho, ?po and comprehensive index. • Both ho and ho/?po of 12° helical scheme are 50% higher than those of segment one. • Correlations formulae of shell side Nuo and Euzo for cothSTHXs are presented. - Abstract: The trisection helical baffled shell-and-tube heat exchangers have structural features of more suitable to the equilateral triangular tube layouts and less baffle parts. In particular the circumferential overlap trisection helical baffled shell-and-tube heat exchangers are of anti-shortcut structure that accommodates one row tubes in each circumferential overlapped zone between adjacent baffles for dampening shortcut leakage. The performance tests were conducted on both oil–water and water–water heat transfer in heat exchangers with equilateral triangle tube layout of 16 tubes including five helical baffle schemes with incline angles of 12°, 16°, 20°, 24°, 28° and a segmental baffled one for comparison. The test results show that both the shell side heat transfer coefficient ho and pressure drop ?po increase but the comprehensive index ho/?po decreases with the increase of the mass flow rate of all schemes; and that the shell side heat transfer coefficient, pressure drop and the comprehensive index ho/?po decrease with the increase of the baffle incline angle at certain mass flow rate, except that the curves of comprehensive index ho/?po of 12° and 16° helical baffle schemes are almost coincide. The average values of shell side heat transfer coefficient, the comprehensive index ho/?po of the 12° helical baffled scheme are about 50% higher than those of the segmental one with almost same pressure drop. The correlation equations for shell side Nusselt number and axial Euler number are presented varying with axial Reynolds number, Prandtl number and helical baffle incline angle

  17. Bifunctional thermoelectric tube made of tilted multilayer material as an alternative to standard heat exchangers.

    Science.gov (United States)

    Takahashi, Kouhei; Kanno, Tsutomu; Sakai, Akihiro; Tamaki, Hiromasa; Kusada, Hideo; Yamada, Yuka

    2013-01-01

    Enormously large amount of heat produced by human activities is now mostly wasted into the environment without use. To realize a sustainable society, it is important to develop practical solutions for waste heat recovery. Here, we demonstrate that a tubular thermoelectric device made of tilted multilayer of Bi(0.5)Sb(1.5)Te3/Ni provides a promising solution. The Bi(0.5)Sb(1.5)Te3/Ni tube allows tightly sealed fluid flow inside itself, and operates in analogy with the standard shell and tube heat exchanger. We show that it achieves perfect balance between efficient heat exchange and high-power generation with a heat transfer coefficient of 4.0 kW/m(2)K and a volume power density of 10 kW/m(3) using low-grade heat sources below 100°C. The Bi(0.5)Sb(1.5)Te3/Ni tube thus serves as a power generator and a heat exchanger within a single unit, which is advantageous for developing new cogeneration systems in factories, vessels, and automobiles where cooling of excess heat is routinely carried out. PMID:23511347

  18. Process heat transfer principles, applications and rules of thumb

    CERN Document Server

    Serth, Robert W

    2014-01-01

    Process Heat Transfer is a reference on the design and implementation of industrial heat exchangers. It provides the background needed to understand and master the commercial software packages used by professional engineers in the design and analysis of heat exchangers. This book focuses on types of heat exchangers most widely used by industry: shell-and-tube exchangers (including condensers, reboilers and vaporizers), air-cooled heat exchangers and double-pipe (hairpin) exchangers. It provides a substantial introduction to the design of heat exchanger networks using pinch technology, the mos

  19. Compact cryocooler heat exchangers

    International Nuclear Information System (INIS)

    Compact heat exchangers are subject to different constraints as a room temperature gas is cooled down by a cold stream returning from a JT valve (or a similar cryoprocess component). In particular, the optimization of exchangers for liquid helium systems has to cover a wide range in temperature and density of the fluid. In the present work we address the following thermodynamic questions: 1. The optimization of intermediate temperatures which optimize stage operation (a stage is assumed to have a constant cross section); 2. The optimum temperature difference available for best overall economic performance values. The results are viewed in the context of porous media concepts applied to rather low speeds of fluid flow in narrow passages. In this paper examples of fluid/solid constraints imposed in this non-classical low temperature area are presented

  20. Counterflow Regolith Heat Exchanger Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat...

  1. Cryogenic regenerative heat exchangers

    CERN Document Server

    Ackermann, Robert A

    1997-01-01

    An in-depth survey of regenerative heat exchangers, this book chronicles the development and recent commercialization of regenerative devices for cryogenic applications. Chapters cover historical background, concepts, practical applications, design data, and numerical solutions, providing the latest information for engineers to develop advanced cryogenic machines. The discussions include insights into the operation of a regenerator; descriptions of the cyclic and fluid temperature distributions in a regenerator; data for various matrix geometries and materials, including coarse and fine bronze, stainless steel-woven wire mesh screens, and lead spheres; and unique operating features of cryocoolers that produce deviations from ideal regenerator theory.

  2. Dynamic characteristics of heat exchanger tubes vibrating in a tube support plate inactive mode

    International Nuclear Information System (INIS)

    Tubes in shell-and-tube heat exchangers, including nuclear plant steam generators, derive their support from longitudinally positioned tube support plates (TSPs). Typically, there is a clearance between the tube and TSP hole. Depending on design and fabrication tolerances, the tube may or may not contact all of the TSPs. Non-contact results in an inactive TSP which can lead to detrimental flow-induced tube vibrations under certain conditions dependent on the resulting tube-TSP interaction dynamics and the fluid excitation forces. The purpose of this study is to investigate the tube-TSP interaction dynamics. Results of an experimental study of damping and natural frequency as functions of tube-TSP diametral clearance and TSP thickness are reported. Calculated values damping ratio and frequency of a tube vibrating within an inactive TSP are also presented together with a comparison of calculated and experimental quantities

  3. Dynamic characteristics of heat exchanger tubes vibrating in a tube support plate inactive mode

    International Nuclear Information System (INIS)

    Tubes in shell-and-tube heat exchangers, including nuclear plant steam generators, derive their support from longitudinally positioned tube support plates (TSPs). Typically there is a clearance between the tube and TSP hole. Depending on design and fabrication tolerances, the tube may or may not contact all of the TSPs. Noncontact results in an inactive TSP which can lead to detrimental flow induced tube vibrations under certain conditions dependent on the resulting tube-TSP interaction dynamics and the fluid excitation forces. The purpose of this study is to investigate the tube-TSP interaction dynamics. Results of an experimental study of damping and natural frequency as functions of tube-TSP diametral clearance and TSP thickness are reported. Calculated values of damping ratio and frequency of a tube vibrating within an inactive TSP are also presented together with a comparison of calculated and experimental quantities

  4. Dynamic characteristics of heat exchanger tubes vibrating in a tube support plate inactive mode

    International Nuclear Information System (INIS)

    Tubes in shell-and-tube heat exchangers, including nuclear plant steam generators, derive their support from longitudinally positioned tube support plates (TSPs). Typically there is a clearance between the tube and TSP hole. Depending on design and fabrication tolerances, the tube may or may not contract all of the TSPs. Noncontact results in an inactive TSP which can lead to detrimental flow induced tube vibrations under certain conditions dependent on the resulting tube-TSP interaction dynamics and the fluid excitation forces. The purpose of this study is to investigate the tube-TSP interaction dynamics. Results of an experimental study of damping and natural frequency as functions of tube-TSP diametral clearance and TSP thickness are reported. Calculated values of damping ratio and frequency of a tube vibrating within an inactive TSP are also presented together with a comparison of calculated and experimental quantities

  5. Heat exchanger performance monitoring guidelines

    International Nuclear Information System (INIS)

    Fouling can occur in many heat exchanger applications in a way that impedes heat transfer and fluid flow and reduces the heat transfer or performance capability of the heat exchanger. Fouling may be significant for heat exchanger surfaces and flow paths in contact with plant service water. This report presents guidelines for performance monitoring of heat exchangers subject to fouling. Guidelines include selection of heat exchangers to monitor based on system function, safety function and system configuration. Five monitoring methods are discussed: the heat transfer, temperature monitoring, temperature effectiveness, delta P and periodic maintenance methods. Guidelines are included for selecting the appropriate monitoring methods and for implementing the selected methods. The report also includes a bibliography, example calculations, and technical notes applicable to the heat transfer method

  6. Heat exchange assembly

    Science.gov (United States)

    Lowenstein, Andrew; Sibilia, Marc; Miller, Jeffrey; Tonon, Thomas S.

    2004-06-08

    A heat exchange assembly comprises a plurality of plates disposed in a spaced-apart arrangement, each of the plurality of plates includes a plurality of passages extending internally from a first end to a second end for directing flow of a heat transfer fluid in a first plane, a plurality of first end-piece members equaling the number of plates and a plurality of second end-piece members also equaling the number of plates, each of the first and second end-piece members including a recessed region adapted to fluidly connect and couple with the first and second ends of the plate, respectively, and further adapted to be affixed to respective adjacent first and second end-piece members in a stacked formation, and each of the first and second end-piece members further including at least one cavity for enabling entry of the heat transfer fluid into the plate, exit of the heat transfer fluid from the plate, or 180.degree. turning of the fluid within the plate to create a serpentine-like fluid flow path between points of entry and exit of the fluid, and at least two fluid conduits extending through the stacked plurality of first and second end-piece members for providing first fluid connections between the parallel fluid entry points of adjacent plates and a fluid supply inlet, and second fluid connections between the parallel fluid exit points of adjacent plates and a fluid discharge outlet so that the heat transfer fluid travels in parallel paths through each respective plate.

  7. Next Generation Microchannel Heat Exchangers

    CERN Document Server

    Ohadi, Michael; Dessiatoun, Serguei; Cetegen, Edvin

    2013-01-01

    In Next Generation Microchannel Heat Exchangers, the authors’ focus on the new generation highly efficient heat exchangers and presentation of novel data and technical expertise not available in the open literature.  Next generation micro channels offer record high heat transfer coefficients with pressure drops much less than conventional micro channel heat exchangers. These inherent features promise fast penetration into many mew markets, including high heat flux cooling of electronics, waste heat recovery and energy efficiency enhancement applications, alternative energy systems, as well as applications in mass exchangers and chemical reactor systems. The combination of up to the minute research findings and technical know-how make this book very timely as the search for high performance heat and mass exchangers that can cut costs in materials consumption intensifies.

  8. Study on pull-out force in tube-and-shell heat exchangers with finite element method

    International Nuclear Information System (INIS)

    Using the finite element method to shell-and-tube multiple fixed-tube plate heat exchanger in three kinds of cases, the pull-out force for a heat exchanger and tube-sheets under the different temperature distribution are calculated. The results show that the pull-out force have a bigger difference in the different locations of a heat exchanger tube for multiple exchangers. According to the allowable value of ASME, the pull-out force of all heat exchanger tubes and tube-sheet joint for case 3 can meet the requirements, but the pull-out force of the joints with 56 heat exchanger tubes and tube-sheets for case 1 and with 22 heat exchanger tubes and tube-sheets for case 2 are over the allowable values. Therefore, under the co-action of vibration, corrosion and so on caused by the flow of the medium,it is easy for these joints to rupture and leak. (authors)

  9. Preliminary Thermal Stress Analysis for Intermediate Heat Exchanger of Prototype SFR

    International Nuclear Information System (INIS)

    They are a shell-and-tube type heat exchanger with counter-current flow heat exchanger mechanism. Each IHX is rated at 98.175 MWt to accommodate the core heat load of 392.6 MWt. For the interactive heat exchange within the IHX, the secondary sodium (non-radioactive sodium) of 324 .deg. C goes into the IHX inner cylinder from a steam generator and the primary sodium (radioactive sodium) of 545 .deg. C enters into the outside of tube bundle from the hot pool. Due to the temperature difference between the primary sodium and secondary sodium, the thermal expansion differences inevitably occurs so that it is necessary to introduce a bellows so as to absorb the thermal expansion. In this study, we investigated a problem for the structural integrity of the IHX which is conceptually designed by using the thermal and structural analysis. In addition we proposed acceptable design concept, and confirmed its structural integrity following the same procedure. In this paper, the structural integrity about the conceptual design of IHX was reviewed and the design should be changed because of its high stress concentration in the upper tubesheet. In new design, the maximum stress decreases up to a reasonable level in virtue of the thermal shield cylinder to protect the heat transfer from the upper tubesheet to IHX inner cylinder. Also, the design requirement of a bellows for accommodating the thermal expansion of the IHX was developed

  10. Preliminary issues associated with the next generation nuclear plant intermediate heat exchanger design.

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Moisseytsev, A.; Majumdar, S.; Shankar, P. S.; Nuclear Engineering Division

    2007-04-05

    The Next Generation Nuclear Plant (NGNP), which is an advanced high temperature gas reactor (HTGR) concept with emphasis on production of both electricity and hydrogen, involves helium as the coolant and a closed-cycle gas turbine for power generation with a core outlet/gas turbine inlet temperature of 900-1000 C. In the indirect cycle system, an intermediate heat exchanger is used to transfer the heat from primary helium from the core to the secondary fluid, which can be helium, nitrogen/helium mixture, or a molten salt. The system concept for the vary high temperature reactor (VHTR) can be a reactor based on the prismatic block of the GT-MHR developed by a consortium led by General Atomics in the U.S. or based on the PBMR design developed by ESKOM of South Africa and British Nuclear Fuels of U.K. This report has made a preliminary assessment on the issues pertaining to the intermediate heat exchanger (IHX) for the NGNP. Two IHX designs namely, shell and tube and compact heat exchangers were considered in the assessment. Printed circuit heat exchanger, among various compact heat exchanger (HX) designs, was selected for the analysis. Irrespective of the design, the material considerations for the construction of the HX are essentially similar, except may be in the fabrication of the units. As a result, we have reviewed in detail the available information on material property data relevant for the construction of HX and made a preliminary assessment of several relevant factors to make a judicious selection of the material for the IHX. The assessment included four primary candidate alloys namely, Alloy 617 (UNS N06617), Alloy 230 (UNS N06230), Alloy 800H (UNS N08810), and Alloy X (UNS N06002) for the IHX. Some of the factors addressed in this report are the tensile, creep, fatigue, creep fatigue, toughness properties for the candidate alloys, thermal aging effects on the mechanical properties, American Society of Mechanical Engineers (ASME) Code compliance information, and performance of the alloys in helium containing a wide range of impurity concentrations. A detailed thermal hydraulic analysis, using a model developed at ANL, was performed to calculate heat transfer, temperature distribution, and pressure drop inside both printed circuit and shell-and-tube heat exchangers. The analysis included evaluation of the role of key process parameters, geometrical factors in HX designs, and material properties. Calculations were performed for helium-to-helium, helium-to-helium/nitrogen, and helium-to-salt HXs. The IHX being a high temperature component, probably needs to be designed using ASME Code Section III, Subsection NH, assuming that the IHX will be classified as a class 1 component. With input from thermal hydraulic calculations performed at ANL, thermal conduction and stress analyses for both compact and shell-and-tube HXs were performed.

  11. Heat exchanger leakage problem location

    Science.gov (United States)

    Hej?ík, Ji?í; Jícha, Miroslav

    2012-04-01

    Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  12. Heat exchanger leakage problem location

    Directory of Open Access Journals (Sweden)

    Jícha Miroslav

    2012-04-01

    Full Text Available Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  13. Heat pipes in modern heat exchangers

    International Nuclear Information System (INIS)

    Heat pipes are very flexible systems with regard to effective thermal control. They can easily be implemented as heat exchangers inside sorption and vapour-compression heat pumps, refrigerators and other types of heat transfer devices. Their heat transfer coefficient in the evaporator and condenser zones is 103-105 W/m2 K, heat pipe thermal resistance is 0.01-0.03 K/W, therefore leading to smaller area and mass of heat exchangers. Miniature and micro heat pipes are welcomed for electronic components cooling and space two-phase thermal control systems. Loop heat pipes, pulsating heat pipes and sorption heat pipes are the novelty for modern heat exchangers. Heat pipe air preheaters are used in thermal power plants to preheat the secondary-primary air required for combustion of fuel in the boiler using the energy available in exhaust gases. Heat pipe solar collectors are promising for domestic use. This paper reviews mainly heat pipe developments in the Former Soviet Union Countries. Some new results obtained in USA and Europe are also included

  14. Experimental research on heat transfer in a coupled heat exchanger

    OpenAIRE

    Liu Yin; Ma Jing; Zhou Guang-Hui; Guan Ren-Bo

    2013-01-01

    The heat exchanger is a devise used for transferring thermal energy between two or more different temperatures. The widespreadly used heat exchanger can only achieve heat exchange between two substances. In this paper, a coupled heat exchanger is proposed, which includes a finned heat exchanger and a double pipe heat exchanger, for multiple heat exchange simultaneously. An experiment is conducted, showing that the average heating capacity increases more tha...

  15. Multidimensional Thermal-Hydraulic Analysis for Decay Heat Exchanger of PGSFR

    International Nuclear Information System (INIS)

    The decay heat exchanger (DHX) of PGSFR is a shell-and-tube type counter-current flow sodium heat exchanger, and each unit is designed for the rated thermal power of 1.0 MWt, which is corresponding to the nominal design capacity of a single passive decay heat removal system (PDHRS) and active decay heat removal system (ADHRS) loops. The DHX unit is fully immersed in the cold sodium pool region and removes the system heat load sufficiently and reliably during the temperature transient. In this work, a multidimensional thermal-hydraulic analysis for the DHX was carried out numerically and the numerical results were compared with the calculated results of the 1-D DHX design code to verify the reliability of the design code. In addition, an influence of the cold pool sodium which flows into the shell-side of the DHX through the shell outlet was evaluated. The SHXSA code was conservative in calculating the pressure drop of the shell-side which is our major concern in designing the natural circulation of the decay heat removal system. It was revealed that the buffer region is needed to reduce the thermal stress in the lower tubesheet by the inflow of the cold pool sodium

  16. Multidimensional Thermal-Hydraulic Analysis for Decay Heat Exchanger of PGSFR

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jonggan; Yoon, Jung; Kim, Dehee; Lee, Tae-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The decay heat exchanger (DHX) of PGSFR is a shell-and-tube type counter-current flow sodium heat exchanger, and each unit is designed for the rated thermal power of 1.0 MWt, which is corresponding to the nominal design capacity of a single passive decay heat removal system (PDHRS) and active decay heat removal system (ADHRS) loops. The DHX unit is fully immersed in the cold sodium pool region and removes the system heat load sufficiently and reliably during the temperature transient. In this work, a multidimensional thermal-hydraulic analysis for the DHX was carried out numerically and the numerical results were compared with the calculated results of the 1-D DHX design code to verify the reliability of the design code. In addition, an influence of the cold pool sodium which flows into the shell-side of the DHX through the shell outlet was evaluated. The SHXSA code was conservative in calculating the pressure drop of the shell-side which is our major concern in designing the natural circulation of the decay heat removal system. It was revealed that the buffer region is needed to reduce the thermal stress in the lower tubesheet by the inflow of the cold pool sodium.

  17. High Temperature Heat Exchanger Project

    Energy Technology Data Exchange (ETDEWEB)

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  18. Experimental and theoretical analysis of the local condensation heat transfer in a plate heat exchanger

    Science.gov (United States)

    Grabenstein, V.; Kabelac, S.

    2012-11-01

    Plate heat exchanger (PHE) are today widely used in industrial heat transfer applications due to their good thermal performance, modest space requirement, easy accessibility to all areas and their lower capital and operating costs as compared to shell-and-tube heat exchangers. Although authoritative models for the design of PHE used as condensers are missing, the number of applications where a PHE is operating as a condenser increases. On the way to a reliable model based on physical approaches for the prediction of heat transfer and pressure drop during the condensation process inside a PHE, the flow and heat interactions as well as their dependence on the geometrical parameters of the corrugated plates and the operating conditions must be studied in detail. In this work the stepwise procedure for the fundamental construction of such a model is described. An experimental setup was built to analyze the characteristics of the two-phase-flow in PHE. A single gap, consisting of two transparent corrugated plates, was tested with a two-phase flow of air/water and also with boiling refrigerant R365mfc. Flow pattern maps were constructed for plates with corrugation angles of 27 and 63 degrees relative to the direction of flow. Investigations of the local heat transfer coefficients and the pressure drop were done with the same plates. The measurement of the local heat transfer coefficients was carried out by the use of the "Temperature Oscillation InfraRed Thermography" (TOIRT) method. Based on these results three main flow patterns are defined: film flow, bubbly flow and slug flow. For each of the three flow patterns an own model for the heat transfer and pressure drop mechanism are developed and the heat transfer coefficient and the friction factor is calculated with different equations depending on the actual steam quality, mass flow and geometrical parameters by means of a flow pattern map. The theory of the flow pattern based prediction models is proved with own experimental data. The measurements were carried out with an experimental setup in a technical scale. The refrigerant cycle works with R134a as refrigerant and involves two PHEs, used as condenser and evaporator, and a 55 kWel compressor for the compression of the vapor phase. The setup allows the measurement of quasi-local heat transfer coefficients inside the PHEs. Additional heat exchangers assure saturated vapor at the inlet and saturated liquid at the outlet of the condenser.

  19. Electroforming thin channel heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Steffani, C.P.

    1991-06-01

    Research at Lawrence Livermore National Laboratory has shown that thin channel heat exchangers can be produced on bimetallic mandrels by the stack and plate method. Depth to width ratios of 100 to 1 are easily produced, with other ratios dependent on heating or cooling requirements. Mass production of these plates may be possible using reel to reel'' methods. Future generations of heat exchangers may be produced via composite electroforming, chemical vapor deposition (CVD) or physical vapor deposition (PVD). 6 refs.

  20. Aplicación del Método de la Colonia de Hormigas Mixto a la optimización de intercambiadores de calor de tubo y coraza / Application of the Mixed Ant Colony Method to the optimization of tube and shell heat exchangers

    Scientific Electronic Library Online (English)

    Maida-Bárbara, Reyes-Rodríguez; Jorge-Laureano, Moya-Rodríguez; Sergio-Ramón, Pérez-León; Gonzalo, Nápoles-Ruiz.

    2014-08-01

    Full Text Available Los procesos de transferencia de calor son uno de los problemas más importantes a resolver en el campo de la Ingeniería. Entre los equipos más usados en la industria para realizar la transferencia de calor están los intercambiadores de calor de tubo y coraza. En el presente trabajo se desarrolla el [...] procedimiento para la optimización del diseño de estos equipos utilizando el método de Kern y aplicando el algoritmo de la colonia de hormigas. Se aplica el mismo a tres ejemplos concretos y los resultados obtenidos se comparan con los obtenidos aplicando otros métodos de la inteligencia artificial. Se optimizan los principales parámetros geométricos de los intercambiadores de calor de tubo y coraza para lograr un menor costo de los mismos. Se demuestra la eficacia del nuevo procedimiento MACO (Mixed Ant Colony Optimization), en el proceso de optimización desde el punto de vista económico utilizando diferentes casos de estudios. Abstract in english Heat transfer processes are one of the most important problems to be solved in the field of Engineering. Among the most widely used equipment for heat transfer in the industry are the shell and tube heat exchangers. This paper develops the procedure for optimizing the design of shell and tube heat e [...] xchangers using the method of Kern and applying the ant colony algorithm. The procedure has been applied to three specific examples and the results obtained are compared with those obtained by applying other methods of artificial intelligence. The main geometric parameters of shell and tube heat exchangers are optimized, to achieve a lower cost of the exchanger. The efficacy of the new procedure MACO (Mixed Ant Colony Optimization) for the optimization process from economically point of view was demonstrated, using different case studies.

  1. Review of Current Experience on Intermediate Heat Exchanger (IHX) and A Recommended Code Approach

    Energy Technology Data Exchange (ETDEWEB)

    Duane Spencer; Kevin McCoy

    2010-02-02

    The purpose of the ASME/DOE Gen IV Task 7 Part I is to review the current experience on various high temperature reactor intermediate heat exchanger (IHX) concepts. There are several different IHX concepts that could be envisioned for HTR/VHTR applications in a range of temperature from 850C to 950C. The concepts that will be primarily discussed herein are: (1) Tubular Helical Coil Heat Exchanger (THCHE); (2) Plate-Stamped Heat Exchanger (PSHE); (3) Plate-Fin Heat Exchanger (PFHE); and (4) Plate-Machined Heat Exchanger (PMHE). The primary coolant of the NGNP is potentially subject to radioactive contamination by the core as well as contamination from the secondary loop fluid. To isolate the radioactivity to minimize radiation doses to personnel, and protect the primary circuit from contamination, intermediate heat exchangers (IHXs) have been proposed as a means for separating the primary circuit of the NGNP (Next Generation Nuclear Plant) or other process heat application from the remainder of the plant. This task will first review the different concepts of IHX that could be envisioned for HTR/VHTR applications in a range of temperature from 850 to 950 C. This will cover shell-and-tube and compact designs (including the platefin concept). The review will then discuss the maturity of the concepts in terms of design, fabricability and component testing (or feedback from experience when applicable). Particular attention will be paid to the feasibility of developing the IHX concepts for the NGNP with operation expected in 2018-2021. This report will also discuss material candidates for IHX applications and will discuss specific issues that will have to be addressed in the context of the HTR design (thermal aging, corrosion, creep, creep-fatigue, etc). Particular attention will be paid to specific issues associated with operation at the upper end of the creep regime.

  2. Review of Current Experience on Intermediate Heat Exchanger (IHX) and A Recommended Code Approach

    International Nuclear Information System (INIS)

    The purpose of the ASME/DOE Gen IV Task 7 Part I is to review the current experience on various high temperature reactor intermediate heat exchanger (IHX) concepts. There are several different IHX concepts that could be envisioned for HTR/VHTR applications in a range of temperature from 850C to 950C. The concepts that will be primarily discussed herein are: (1) Tubular Helical Coil Heat Exchanger (THCHE); (2) Plate-Stamped Heat Exchanger (PSHE); (3) Plate-Fin Heat Exchanger (PFHE); and (4) Plate-Machined Heat Exchanger (PMHE). The primary coolant of the NGNP is potentially subject to radioactive contamination by the core as well as contamination from the secondary loop fluid. To isolate the radioactivity to minimize radiation doses to personnel, and protect the primary circuit from contamination, intermediate heat exchangers (IHXs) have been proposed as a means for separating the primary circuit of the NGNP (Next Generation Nuclear Plant) or other process heat application from the remainder of the plant. This task will first review the different concepts of IHX that could be envisioned for HTR/VHTR applications in a range of temperature from 850 to 950 C. This will cover shell-and-tube and compact designs (including the platefin concept). The review will then discuss the maturity of the concepts in terms of design, fabricability and component testing (or feedback from experience when applicable). Particular attention will be paid to the feasibility of developing the IHX concepts for the NGNP with operation expected in 2018-2021. This report will also discuss material candidates for IHX applications and will discuss specific issues that will have to be addressed in the context of the HTR design (thermal aging, corrosion, creep, creep-fatigue, etc). Particular attention will be paid to specific issues associated with operation at the upper end of the creep regime.

  3. Simulations of thermal-hydraulic processes in heat exchangers- station of the cogeneration power plant

    Energy Technology Data Exchange (ETDEWEB)

    Studovic, M.; Stevanovic, V.; Ilic, M.; Nedeljkovic, S. [Faculty of Mechanical Engineering of Belgrade (Croatia)

    1995-12-31

    Design of the long district heating system to Belgrade (base load 580 MJ/s) from Thermal Power Station `Nikola Tesla A`, 30 km southwest from the present gas/oil burning boilers in New Belgrade, is being conducted. The mathematical model and computer code named TRP are developed for the prediction of the design basis parameters of heat exchangers station, as well as for selection of protection devices and formulation of operating procedures. Numerical simulations of heat exchangers station are performed for various transient conditions: up-set and abnormal. Physical model of multi-pass, shell and tube heat exchanger in the station represented is by unique steam volume, and with space discretised nodes both for water volume and tube walls. Heat transfer regimes on steam and water side, as well as hydraulic calculation were performed in accordance with TEMA standards for transient conditions on both sides, and for each node on water side. Mathematical model is based on balance equations: mass and energy for lumped parameters on steam side, and energy balances for tube walls and water in each node. Water mass balance is taken as boundary/initial condition or as specified control function. The physical model is proposed for (s) heat exchangers in the station and (n) water and wall volumes. Therefore, the mathematical model consists of 2ns+2, non-linear differential equations, including equations of state for water, steam and tube material, and constitutive equations for heat transfer on steam and water side, solved by the Runge-Kutt method. Five scenarios of heat exchangers station behavior have been simulated with the TRP code and obtained results are presented. (author)

  4. A minichannel aluminium tube heat exchanger - Pt. 2: Evaporator performance with propane

    Energy Technology Data Exchange (ETDEWEB)

    Fernando, Primal; Palm, Bjoern; Ameel, Tim; Lundqvist, Per; Granryd, Eric [Department of Energy Technology, Division of Applied Thermodynamics and Refrigeration, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden)

    2008-06-15

    This paper presents heat transfer data for a multiport minichannel heat exchanger vertically mounted as an evaporator in a test-rig simulating a small water-to-water heat pump. The multiport minichannel heat exchanger was designed similar to a shell-and-tube type heat exchanger, with a six-channel tube of 1.42 mm hydraulic diameter, a tube-side heat transfer area of 0.777 m{sup 2} and a shell-side heat transfer area of 0.815 m{sup 2}. Refrigerant propane with a desired vapour quality flowed upward through the tubes and exited with a desired superheat of 1-4 K. A temperature-controlled glycol solution that flowed downward on the shell-side supplied the heat for the evaporation of the propane. The heat transfer rate between the glycol solution and propane was controlled by varying the evaporation temperature and propane mass flow rate while the glycol flow rate was fixed (18.50 l min{sup -1}). Tests were conducted for a range of evaporation temperatures from -15 to +10{sup o}C, heat flux from 2000 to 9000 W m{sup -2} and mass flux from 13 to 66 kg m{sup -2} s{sup -1}. The heat transfer coefficients were compared with 14 correlations found in the literature. The experimental heat transfer coefficients were higher than those predicted by many of the correlations. A correlation which was previously developed for a very large and long tube (21 mm diameter and 10 m long) was in good agreement with the experimental data (97% of the data within {+-}30%). Several other correlations were able to predict the data within a reasonable deviation (within {+-}30%) after some adjustments to the correlations. (author)

  5. Heat exchanger with ceramic elements

    Science.gov (United States)

    Corey, John A. (North Troy, NY)

    1986-01-01

    An annular heat exchanger assembly includes a plurality of low thermal growth ceramic heat exchange members with inlet and exit flow ports on distinct faces. A mounting member locates each ceramic member in a near-annular array and seals the flow ports on the distinct faces into the separate flow paths of the heat exchanger. The mounting member adjusts for the temperature gradient in the assembly and the different coefficients of thermal expansion of the members of the assembly during all operating temperatures.

  6. Heat exchanger using graphite foam

    Science.gov (United States)

    Campagna, Michael Joseph; Callas, James John

    2012-09-25

    A heat exchanger is disclosed. The heat exchanger may have an inlet configured to receive a first fluid and an outlet configured to discharge the first fluid. The heat exchanger may further have at least one passageway configured to conduct the first fluid from the inlet to the outlet. The at least one passageway may be composed of a graphite foam and a layer of graphite material on the exterior of the graphite foam. The layer of graphite material may form at least a partial barrier between the first fluid and a second fluid external to the at least one passageway.

  7. Cost effective heat exchanger network design with mixed materials of construction

    International Nuclear Information System (INIS)

    This paper presents a simple methodology for cost estimation of a near optimal heat exchanger network, which comprises mixed materials of construction. In traditional pinch technology and mathematical programming it is usually assumed that all heat exchangers in a network obey a single cost model. This implies that all heat exchangers in a network are of the same type and use the same materials of construction (an assumption that is unwarranted). The method introduced in this article enables the designer to decomposes the total cost of a heat exchanger into two elements, namely cost of the tubes and cost of the shell, thereby predict a more reliable cost for the network. By subsequent use of the binary variables and evaluation of the physical conditions of the streams, one can assign the streams to pass either through shell or tubes. Whereby, shell and tubes can be of different materials and therefore different cost models can be applied. Another advantage of the approach is that the pressure drop in each side of the exchanger (shell or tubes) can be assessed leading to more accurate evaluation of corresponding heat transfer coefficient for each individual stream. Finally an objective function (total cost) can be defined based on mixed materials of construction and different values of heat transfer coefficients. The proposed model has been utilized in three different case studies and the results are compared with those of a commercially available software (Super Target). The comparison shows reductions of more than 17% and 14% in total annual costs in the two cases, and 2.5% reduction in third, confirming the fact that more accurate evaluation of heat transfer coefficient for each individual stream can lead to better network design

  8. Tube in shell heat exchangers

    International Nuclear Information System (INIS)

    An improved tube-in-shell heat exchanger to be used between liquid metal and water is described for use in the liquid metal coolant system of fast breeder reactors. It is stated that this design is less prone to failures which could result in sodium water reactions than previous exchangers. (UK)

  9. Heat exchanger and related methods

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Terry D.; McKellar, Michael G.

    2015-12-22

    Heat exchangers include a housing having an inlet and an outlet and forming a portion of a transition chamber. A heating member may form another portion of the transition chamber. The heating member includes a first end having a first opening and a second end having a second opening larger than the first opening. Methods of conveying a fluid include supplying a first fluid into a transition chamber of a heat exchanger, supplying a second fluid into the transition chamber, and altering a state of a portion of the first fluid with the second fluid. Methods of sublimating solid particles include conveying a first fluid comprising a material in a solid state into a transition chamber, heating the material to a gaseous state by directing a second fluid through a heating member and mixing the first fluid and the second fluid.

  10. Effect of channel configurations for tritium transfer in printed circuit heat exchangers

    International Nuclear Information System (INIS)

    The Next Generation Nuclear Plant (NGNP), a very High temperature Gas-Cooled Reactor (VHTR) concept, will provide the first demonstration of a closed-loop Brayton cycle at a commercial scale of a few hundred megawatts electric and hydrogen production. The power conversion system (PCS) for the NGNP will take advantage of the significantly higher reactor outlet temperatures of the VHTR to provide higher efficiencies than can be achieved in the current generation of light water reactors. Besides demonstrating a system design that can be used directly for subsequent commercial deployment, the NGNP will demonstrate key technology elements that can be used in subsequent advanced power conversion systems for other Generation IV reactors. In anticipation of the design, development and procurement of an advanced power conversion system for the NGNP, the system integration of the NGNP and hydrogen plant was initiated to identify the important design and technology options that must be considered in evaluating the performance of the proposed NGNP. In the VHTR system, an intermediate heat exchanger (IHX), which transfers heat from the reactor core to the electricity or hydrogen production system is one key component, and its effectiveness is directly related to the system overall efficiency. In the VHTRs, the gas fluids used for coolant generally have poor heat transfer capability, so it requires very large surface area for a given condition. For this reason, a compact heat exchanger (CHE), which is widely used in industry especially for gas-to-gas or gas-to-liquid heat exchange is considered as a potential candidate for an IHX replacing the classical shell and tube type heat exchanger. A compact heat exchanger is arbitrary referred to be a heat exchanger having a surface area density greater than 700 m2/m3. The compactness is usually achieved by fins and micro-channels, and leads to the enormous heat transfer enhancement and size reduction. The surface area density is the total heat transfer area divided by the volume of the heat exchanger. In the case of PCHE units, the heat transfer surface area density may be as high as 2,500 m2/m3. This high compactness implies an appreciable reduction in material reducing cost. In this study, heat transfer and tritium penetration analyses have been performed for two different channel configurations of the PCHE; (1) standard and (2) off-set. One of the goals of this study was to determine whether offsetting the hot and cold streams would significantly reduce the tritium flux, and whether or not it would affect the heat transfer significantly. (author)

  11. Effect of Channel Configurations for Tritium Transfer in Printed Circuit Heat Exchangers

    International Nuclear Information System (INIS)

    The Next Generation Nuclear Plant (NGNP), a very High temperature Gas-Cooled Reactor (VHTR) concept, will provide the first demonstration of a closed-loop Brayton cycle at a commercial scale of a few hundred megawatts electric and hydrogen production. The power conversion system (PCS) for the NGNP will take advantage of the significantly higher reactor outlet temperatures of the VHTR to provide higher efficiencies than can be achieved in the current generation of light water reactors. Besides demonstrating a system design that can be used directly for subsequent commercial deployment, the NGNP will demonstrate key technology elements that can be used in subsequent advanced power conversion systems for other Generation IV reactors. In anticipation of the design, development and procurement of an advanced power conversion system for the NGNP, the system integration of the NGNP and hydrogen plant was initiated to identify the important design and technology options that must be considered in evaluating the performance of the proposed NGNP. In the VHTR system, an intermediate heat exchanger (IHX), which transfers heat from the reactor core to the electricity or hydrogen production system is one key component, and its effectiveness is directly related to the system overall efficiency. In the VHTRs, the gas fluids used for coolant generally have poor heat transfer capability, so it requires very large surface area for a given condition. For this reason, a compact heat exchanger (CHE), which is widely used in industry especially for gasto-gas or gas-to-liquid heat exchange is considered as a potential candidate for an IHX replacing the classical shell and tube type heat exchanger. A compact heat exchanger is arbitrary referred to be a heat exchanger having a surface area density greater than 700 m2/m3. The compactness is usually achieved by fins and micro-channels, and leads to the enormous heat transfer enhancement and size reduction. The surface area density is the total heat transfer area divided by the volume of the heat exchanger. In the case of PCHE units, the heat transfer surface area density may be as high as 2,500 m2/m3. This high compactness implies an appreciable reduction in material reducing cost. In this study, heat transfer and tritium penetration analyses have been performed for two different channel configurations of the PCHE; (1) standard and (2) off-set. One of the goals of this study was to determine whether offsetting the hot and cold streams would significantly reduce the tritium flux, and whether or not it would affect the heat transfer significantly.

  12. Adaptive predictive control of laboratory heat exchanger

    OpenAIRE

    Bobál, Vladimír; Kubal?ík, Marek; Dostál, Petr; Novák, Jakub

    2014-01-01

    Heat exchange belongs to the class of basic thermal processes which occur in a range of industrial technologies, particularly in the energetic, chemical, polymer and rubber industry. The process of heat exchange is often implemented by through-flow heat exchangers. It is apparent that for an exact theoretical description of dynamics of heat exchange processes it is necessary to use partial differential equations. Heat exchange is namely a process with distributed parameters. It is also necess...

  13. Heat Exchangers Analysis

    Directory of Open Access Journals (Sweden)

    S.C. Pang

    2013-01-01

    Full Text Available Current research performs mathematics correlations between engine speed, coolant flow, vehicle speed and driving gear. A step-by-step procedure is described to obtain the engine cooling system parameters mathematically (include a CFD model. After obtaining the parameters, the thermal equilibrium of engine cooling system is studied thoroughly. The study of thermal equilibrium provides some insights on how to reduce engine cooling load and when the interference of cooling fan is required. A segmented spread sheet model is developed in order to explain the phenomenon which air flow driven by uniform ram air could dissipate higher amount of heat flow than air flow driven by cooling fan. The segmentation analysis concluded that minimum mCp fluid is switched to coolant when the air flow is concentrated at small portion of area.

  14. Heat exchanger staybolt acceptance criteria

    International Nuclear Information System (INIS)

    The structural integrity demonstration of the primary coolant piping system includes evaluating the structural capacity of each component against a large break or equivalent Double-Ended Guillotine Break. A large break at the inlet or outlet heads of the heat exchangers would occur if the restraint members of the heads become inactive. The structural integrity of the heads is demonstrated by showing the redundant capacity of the staybolts to restrain the head at design conditions and under seismic loadings. The Savannah River Site heat exchanger head is attached to the tubesheet by 84 staybolts. Access to the staybolts is limited due to a welded seal cap over the staybolts. An ultrasonic testing (UT) inspection technique to provide an in-situ examination of the staybolts has recently been developed at SRS. Examination of the staybolts will be performed to ensure their service condition and configuration is within acceptance limits. An acceptance criteria methodology has been developed to disposition flaws reported in the staybolt inspections while ensuring adequate restraint capacity of the staybolts to maintain integrity of the heat exchanger heads against collapse. The methodology includes an approach for the baseline and periodic inspections of the staybolts. The heat exchanger head is analyzed with a three-dimensional finite element model. The restraint provided by the staybolts is evaluated for several postulated cases of inactive or missing staybolts. Evaluation of specific, inactive staybolt configurations based on the UT results can be performed with the finite element model and fracture methodology in this report

  15. Heat exchanger with oscillating flow

    Science.gov (United States)

    Scotti, Stephen J. (Inventor); Blosser, Max L. (Inventor); Camarda, Charles J. (Inventor)

    1993-01-01

    Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit.

  16. Development of Design Criteria for Fluid Induced Structural Vibration in Steam Generators and Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Catton, Ivan; Dhir, Vijay K.; Alquaddoomi, O.S.; Mitra, Deepanjan; Adinolfi, Pierangelo

    2004-03-26

    OAK-B135 Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers. In the nuclear industry, steam generators are often affected by this problem. However, flow-induced vibration is not limited to nuclear power plants, but to any type of heat exchanger used in many industrial applications such as chemical processing, refrigeration and air conditioning. Specifically, shell and tube type heat exchangers experience flow-induced vibration due to the high velocity flow over the tube banks. Flow-induced vibration in these heat exchangers leads to equipment breakdown and hence expensive repair and process shutdown. The goal of this research is to provide accurate measurements that can help modelers to validate their models using the measured experimental parameters and thereby develop better design criteria for avoiding fluid-elastic instability in heat exchangers. The research is divided between two primary experimental efforts, the first conducted using water alone (single phase) and the second using a mixture of air or steam and water as the working fluid (two phase). The outline of this report is as follows: After the introduction to fluid-elastic instability, the experimental apparatus constructed to conduct the experiments is described in Chapter 2 along with the measurement procedures. Chapter 3 presents results obtained on the tube array and the flow loop, as well as techniques used in data processing. The project performance is described and evaluated in Chapter 4 followed by a discussion of publications and presentations relevant to the project in Chapter 5, while the conclusions and recommendations for future work are presented in Chapter 6.

  17. Development of Design Criteria for Fluid Induced Structural Vibrations in Steam Generators and Heat Exchangers

    International Nuclear Information System (INIS)

    OAK-B135 Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers. In the nuclear industry, steam generators are often affected by this problem. However, flow-induced vibration is not limited to nuclear power plants, but to any type of heat exchanger used in many industrial applications such as chemical processing, refrigeration and air conditioning. Specifically, shell and tube type heat exchangers experience flow-induced vibration due to the high velocity flow over the tube banks. Flow-induced vibration in these heat exchangers leads to equipment breakdown and hence expensive repair and process shutdown. The goal of this research is to provide accurate measurements that can help modelers to validate their models using the measured experimental parameters and thereby develop better design criteria for avoiding fluid-elastic instability in heat exchangers. The research is divided between two primary experimental efforts, the first conducted using water alone (single phase) and the second using a mixture of air or steam and water as the working fluid (two phase). The outline of this report is as follows: After the introduction to fluid-elastic instability, the experimental apparatus constructed to conduct the experiments is described in Chapter 2 along with the measurement procedures. Chapter 3 presents results obtained on the tube array and the flow loop, as well as techniques used in data processing. The project performance is described and evaluated in Chapter 4 followed by a discussion of publications and presentations relevant to the project in Chapter 5, while the conclusions and recommendations for future work are presented in Chapter 6

  18. Heat exchanges in coarsening systems

    International Nuclear Information System (INIS)

    This paper is a contribution to the understanding of the thermal properties of ageing systems where statistically independent degrees of freedom with greatly separated time scales are expected to coexist. Focusing on the prototypical case of quenched ferromagnets, where fast and slow modes can be respectively associated with fluctuations in the bulk of the coarsening domains and in their interfaces, we perform a set of numerical experiments specifically designed to compute the heat exchanges between different degrees of freedom. Our studies promote a scenario with fast modes acting as an equilibrium reservoir to which interfaces may release heat through a mechanism that allows fast and slow degrees to maintain their statistical properties independently

  19. DHE (downhole heat exchangers). [Downhole Heat Exchangers (DHE)

    Energy Technology Data Exchange (ETDEWEB)

    Culver, G.

    1990-11-01

    The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive -- that is, no or very little geothermal water or steam is produced from the well either reducing or completely eliminating surface environmental concerns and the need for disposal systems or injection wells. Initial cost of pumps and installation are eliminated or reduced along with pumping power costs and maintenance costs associated with pumping often corrosive geothermal fluids. Many residential and small commercial systems do not require circulating pumps because the density difference in the incoming and outgoing sides of the loop are sufficient to overcome circulating friction losses in the entire system. The major disadvantage of DHEs is their dependence on natural heat flow. In areas where geological conditions provide high permeability and a natural hydraulic gradient, DHEs can provide a substantial quantity of heat. A single 500-ft (152 m) well in Klamath Falls, Oregon, supplies over one megawatt thermal and output is apparently limited by the surface area of pipe that can be installed in the well bore. In contrast, DHEs used in conjunction with heat pumps may supply less than 8 KW from a well of similar depth. Here output is limited by conductive heat flow with perhaps a small contribution from convection near the well bore. The highest capacity DHE reported to date, in Turkey, supplies 6 MW thermal from an 820-ft (250 m) well. There were two main goals for this project. The first was to gather, disseminate and exchange internationally information on DHES. The second was to perform experiments that would provide insight into well bore/aquifer interaction and thereby provide more information on which to base DHE designs. 27 refs., 31 figs., 3 tabs.

  20. Cryogenic Heat Exchanger with Turbulent Flows

    Science.gov (United States)

    Amrit, Jay; Douay, Christelle; Dubois, Francis; Defresne, Gerard

    2012-01-01

    An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N[subscript 2] and He gases from room temperatures. We present first the experimental results of…

  1. Optimization of heat exchanger for indirectly heated water heater

    Science.gov (United States)

    Kaduchová, Katarína; Lenhard, Richard; Janda?ka, Jozef

    2012-04-01

    Due to the optimization of geometrical parameters of the heat exchanger in indirect heated water heaters created a mathematical model of heating hot water, by which I have subsequently made the simulation of the device to change its geometrical parameters. Based on these results, the impacts of the geometrical parameters affect the performance of the heat exchanger. The results of the optimization to create a CFD model which watched at the behavior of optimized heat exchanger for indirect heated water heaters.

  2. Free vibrations of finite circular cylindrical shells and tubes with and without a surrounding fluid

    International Nuclear Information System (INIS)

    Numerical models are evaluated for determining the natural frequencies of thin-walled closed circular cylindrical shells and straight tube bundles in a fluid or without a fluid. Experiments are described to check the reliability of the numerical models. Some of the models are applied for the vibration analysis of some parts of the sodium-steam heat exchangers of the SNR-300 reactor in Kalkar (West Germany). (Auth.)

  3. Comparison of a Conventional Heat Exchangers with a New Designed Heat Exchanger Experimentally

    Directory of Open Access Journals (Sweden)

    Tansel Koyun

    2014-04-01

    Full Text Available In this study, the air-water heat exchanger designed have been experimentally compared to conventional heat exchangers with and without fin. The same parameters for the three heat exchangers (pump flow, heating power, etc... have been used. In the experiments, speed-flow adjustment has been made to supply heat transfer at an optimum. As a result, during the circulation of water in pipe of the air-water heat exchanger, the corrosion fouling factor has not been formed. In addition, the efficiency of the new designed heat exchanger has been found between fin and finless heat exchanger efficiencies. The results have been shown in the diagrams.

  4. HEAT EXCHANGE IN SLOT-HOLE RECUPERATORS

    OpenAIRE

    Rovin, L. E.; L. N. Rusaja

    2015-01-01

    At calculation of slot heat exchangers it is necessary to take into account the additional stream of heat transferred by emission from internal wall to an external one and further distributed between heated air and environment.

  5. Heat exchanger for solar water heaters

    Science.gov (United States)

    Cash, M.; Krupnick, A. C.

    1977-01-01

    Proposed efficient double-walled heat exchanger prevents contamination of domestic water supply lines and indicates leakage automatically in solar as well as nonsolar heat sources using water as heat transfer medium.

  6. Heat exchanger thermal insulation system

    International Nuclear Information System (INIS)

    The heat exchanger insulation system described includes an outer ring, a bundle of circulation tubes connected at their ends to a tube plate and comprising a coaxial cylindrical sleeve around each tube with play along a part of its length near the ends connected to the tube plate. The sleeves are suspended by their upper ends to a perforated plate with holes into which the sleeves fit, the perforated plate being fixed to a ring fitted by its base to the tube plate by means of tie rods between the tube plate and the perforated plate. This system has been particularly designed for liquid sodium cooled reactors

  7. Optimization of heat exchanger for indirectly heated water heater

    OpenAIRE

    Kaduchová Katarína; Lenhard Richard; Janda?ka Jozef

    2012-01-01

    Due to the optimization of geometrical parameters of the heat exchanger in indirect heated water heaters created a mathematical model of heating hot water, by which I have subsequently made the simulation of the device to change its geometrical parameters. Based on these results, the impacts of the geometrical parameters affect the performance of the heat exchanger. The results of the optimization to create a CFD model which watched at the behavior of optimized heat exchanger for indirect hea...

  8. Membrane and plastic heat exchangers performance

    Directory of Open Access Journals (Sweden)

    Masud Behnia

    2005-09-01

    Full Text Available The performance of a membrane-based heat exchanger utilizing porous paper as the heat and moisture transfer media is presented. The measured performance is compared with a plastic film heat exchanger. This novel heat exchanger is used in ventilation energy recovery systems. The results show that the sensible effectiveness is higher than the latent effectiveness. When a similar experiment was conducted using a plastic film heat exchanger surface instead of paper, where only heat is transferred, the sensible effectiveness values were lower than the effectiveness values recorded when the paper heat exchanger is used. Furthermore, energy analysis shows that utilizing a paper surface heat exchanger in a standard air conditioning system will lead to significant energy savings.

  9. NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

    2008-09-01

    One key long-standing issue that must be overcome to fully realize the successful growth of nuclear power is to determine other benefits of nuclear energy apart from meeting the electricity demands. The Next Generation Nuclear Plant (NGNP) will most likely be producing electricity and heat for the production of hydrogen and/or oil retrieval from oil sands and oil shale to help in our national pursuit of energy independence. For nuclear process heat to be utilized, intermediate heat exchange is required to transfer heat from the NGNP to the hydrogen plant or oil recovery field in the most efficient way possible. Development of nuclear reactor - process heat technology has intensified the interest in liquid metals as heat transfer media because of their ideal transport properties. Liquid metal heat exchangers are not new in practical applications. An important rational for considering liquid metals is the potential convective heat transfer is among the highest known. Thus explains the interest in liquid metals as coolant for intermediate heat exchange from NGNP. For process heat it is desired that, intermediate heat exchangers (IHX) transfer heat from the NGNP in the most efficient way possible. The production of electric power at higher efficiency via the Brayton Cycle, and hydrogen production, requires both heat at higher temperatures and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. Compact heat exchangers maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. High temperature IHX design requirements are governed in part by the allowable temperature drop between the outlet and inlet of the NGNP. In order to improve the characteristics of heat transfer, liquid metal phase change heat exchangers may be more effective and efficient. This paper explores the overall heat transfer characteristics and pressure drop of the phase change heat exchanger with Na as the heat exchanger coolant. In order to design a very efficient and effective heat exchanger one must optimize the design such that we have a high heat transfer and a lower pressure drop, but there is always a trade-off between them. Based on NGNP operational parameters, a heat exchanger analysis with the sodium phase change will be presented to show that the heat exchanger has the potential for highly effective heat transfer, within a small volume at reasonable cost.

  10. NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger

    International Nuclear Information System (INIS)

    One key long-standing issue that must be overcome to fully realize the successful growth of nuclear power is to determine other benefits of nuclear energy apart from meeting the electricity demands. The Next Generation Nuclear Plant (NGNP) will most likely be producing electricity and heat for the production of hydrogen and/or oil retrieval from oil sands and oil shale to help in our national pursuit of energy independence. For nuclear process heat to be utilized, intermediate heat exchange is required to transfer heat from the NGNP to the hydrogen plant or oil recovery field in the most efficient way possible. Development of nuclear reactor--process heat technology has intensified the interest in liquid metals as heat transfer media because of their ideal transport properties. Liquid metal heat exchangers are not new in practical applications. An important rational for considering liquid metals is the potential convective heat transfer is among the highest known. Thus explains the interest in liquid metals as coolant for intermediate heat exchange from NGNP. For process heat it is desired that, intermediate heat exchangers (IHX) transfer heat from the NGNP in the most efficient way possible. The production of electric power at higher efficiency via the Brayton Cycle, and hydrogen production, requires both heat at higher temperatures and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. Compact heat exchangers maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. High temperature IHX design requirements are governed in part by the allowable temperature drop between the outlet and inlet of the NGNP. In order to improve the characteristics of heat transfer, liquid metal phase change heat exchangers may be more effective and efficient. This paper explores the overall heat transfer characteristics and pressure drop of the phase change heat exchanger with Na as the heat exchanger coolant. In order to design a very efficient and effective heat exchanger one must optimize the design such that we have a high heat transfer and a lower pressure drop, but there is always a trade-off between them. Based on NGNP operational parameters, a heat exchanger analysis with the sodium phase change will be presented to show that the heat exchanger has the potential for highly effective heat transfer, within a small volume at reasonable cost

  11. Heat recovery from a cement plant with a Marnoch Heat Engine

    International Nuclear Information System (INIS)

    This paper examines the performance of a new Marnoch Heat Engine (MHE) that recovers waste heat from within a typical cement plant. Two MHE units with compressed air as the working fluid are installed to recover the waste heat. The first unit on the main stack has four pairs of shell and tube heat exchangers. The second heat recovery unit is installed on a clinker quenching system. This unit operates with three pairs of shell and tube heat exchangers. The recovered heat is converted to electricity through the MHE system and used internally within the cement plant. A predictive model and results are presented and discussed. The results show the promising performance of the MHE's capabilities for efficient generation of electricity from waste heat sources in a cement plant. The new heat recovery system increases the efficiency of the cement plant and lowers the CO2 emissions from the clinker production process. Moreover, it reduces the amount of waste heat to the environment and lowers the temperature of the exhaust gases. - Highlights: ? This paper examines the thermodynamic performance of a new Marnoch Heat Engine (MHE) that recovers waste heat to produce electricity and improve the operating efficiency of a typical cement plant. ? The first unit of the MHE on the main stack has four pairs of shell and tube heat exchangers and the second heat recovery unit is installed on a clinker quenching system. ? Both predicted and experimental results demonstrate the promising performance of the MHE's capabilities for efficient generation of electricity from waste heat sources in a cement plant.

  12. Air-sand heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Torsten; Zunft, Stefan [German Aerospace Center (DLR), Stuttgart (Germany); Boura, Cristiano; Eckstein, Julian; Felinks, Jan; Goettsche, Joachim; Hoffschmidt, Bernhard; Schmitz, Stefan [FH Aachen, Juelich (Germany). Solar-Inst. Juelich

    2011-07-01

    This paper summarizes research activities that analyse the thermodynamic behaviour of an Air / Sand Heat Exchanger, developed by Solar-Institut Juelich (SIJ) and the German Aerospace Centre (DLR). A numerical 3-D model, new results and a model validation of this particular cross-flow heat exchanger are presented. Simulation results were obtained for sand with 1-2 mm grain size. The simulation was validated with operational results of a new 15 kW prototype unit. Ansys, including Ansys-CFX, is used as modelling and simulation platform. The bulk material is modelled by a porous solid medium without structural dynamic interaction between fluid and solid phase. For pressure drop calculations, Ergun's model for bulk material is used. The model parameters were validated and fitted with measured values of a separate pressure drop test rig. The validation was done with quartz sand. To determine the suitability of available granular products for this application, tests have been conducted regarding the thermomechanical properties as well as their attrition behaviour and abrasion on various wall materials.

  13. Improved ceramic heat exchange material

    Science.gov (United States)

    Mccollister, H. L.

    1977-01-01

    Improved corrosion resistant ceramic materials that are suitable for use as regenerative heat exchangers for vehicular gas turbines is reported. Two glass-ceramic materials, C-144 and C-145, have superior durability towards sulfuric acid and sodium sulfate compared to lithium aluminosilicate (LAS) Corning heat exchange material 9455. Material C-144 is a leached LAS material whose major crystalline phase is silica keatite plus mullite, and C-145 is a LAS keatite solid solution (S.S.) material. In comparison to material 9455, material C-144 is two orders of magnitude better in dimensional stability to sulfuric acid at 300 C, and one order of magnitude better in stability to sodium sulfate at 1000 C. Material C-145 is initially two times better in stability to sulfuric acid, and about one order of magnitude better in stability to sodium sulfate. Both C-144 and C-145 have less than 300 ppm delta L/L thermal expansion from ambient to 1000 C, and good dimensional stability of less than approximately 100 ppm delta L/L after exposure to 1000 C for 100 hours. The glass-ceramic fabrication process produced a hexagonal honeycomb matrix having an 85% open frontal area, 50 micrometer wall thickness, and less than 5% porosity.

  14. Mathematical simulation of heat exchanger working conditions

    Directory of Open Access Journals (Sweden)

    Gavlas Stanislav

    2015-01-01

    Full Text Available One of the When designing a new heat exchanger it is necessary to consider all the conditions imposed on the exchanger and its desired properties. Most often the investigation of heat transfer is to find heat surface. When applying exchanger for proposed hot air engine, it will be a counter-flow heat exchanger of gas - gas type. Gas, which transfers the heat will be exhaust gas from the combustion of biomass. An important step in the design and verification is to analyze exchanger designed using numerical methods, the verification of the correctness of design and verification of boundary conditions which include temperatures, flow rates and pressure drops. Due to the fact that the heat transfer in the heat exchanger is a three-dimensional plot and timeindependent, the system is described by partial differential equations that need to be solved by numerical methods.

  15. Mathematical simulation of heat exchanger working conditions

    Science.gov (United States)

    Gavlas, Stanislav; ?ur?anský, Peter; Lenhard, Richard; Janda?ka, Jozef

    2015-05-01

    One of the When designing a new heat exchanger it is necessary to consider all the conditions imposed on the exchanger and its desired properties. Most often the investigation of heat transfer is to find heat surface. When applying exchanger for proposed hot air engine, it will be a counter-flow heat exchanger of gas - gas type. Gas, which transfers the heat will be exhaust gas from the combustion of biomass. An important step in the design and verification is to analyze exchanger designed using numerical methods, the verification of the correctness of design and verification of boundary conditions which include temperatures, flow rates and pressure drops. Due to the fact that the heat transfer in the heat exchanger is a three-dimensional plot and timeindependent, the system is described by partial differential equations that need to be solved by numerical methods.

  16. Testing and analysis of immersed heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Farrington, R.B.; Bingham, C.E.

    1986-08-01

    The objectives were to determine the performance of four immersed, ''supply-side'' heat exchangers used in solar domestic-hot-water systems; to examine the effects of flow rate, temperature difference, and coil configuration on performance; and to develop a simple model to predict the performance of immersed heat exchangers. We tested four immersed heat exchangers: a smooth coil, a finned spiral, a single-wall bayonet, and a double-wall bayonet. We developed two analyticl models and a simple finite difference model. We experimentally verified that the performance of these heat exchangers depends on the flow rate through them; we also showed that the temperature difference between the heat exchanger's inlet and the storage tank can strongly affect a heat exchanger's performance. We also compared the effects of the heat exchanger's configuration and correlated Nusselt and Rayleigh numbers for each heat exchanger tested. The smooth coil had a higher effectiveness than the others, while the double-wall bayonet had a very low effectiveness. We still do not know the long-term effectiveness of heat exchangers regarding scale accumulation, nor do we know the effects of very low flow rates on a heat exchanger's performance.

  17. Analytical Entropy Analysis of Recuperative Heat Exchangers

    OpenAIRE

    Marija Zivic; Zdravko Virag; Antun Galovic

    2003-01-01

    Abstract: The analytical solutions for the temperature variation of two streams in parallel flow, counter flow and cross-flow heat exchangers and related entropy generation due to heat exchange between the streams are presented. The analysis of limiting cases for the relative entropy generation is performed, and corresponding analytical expressions are given. The obtained results may be included in a more general procedure concerning optimal heat exchanger design.

  18. Comparative Study of Heat Exchangers Using CFD

    OpenAIRE

    Melvinraj C R; Vishal Varghese C

    2014-01-01

    A parallel flow heat exchanger and a corresponding ribbed tube heat exchanger is modeled and numerically analysed using a commercial finite volume CFD package. Pro-E & ANSYS 14.5 softwares are used for the designing and the analysis. CFD predictions of effectiveness of the two heat exchangers are obtained and compared. After selecting the best modeling approach, the sensitivity of the results to particular flow rate is investigated. It is observed that the flow and the tempera...

  19. Micro tube heat exchangers for Space Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Mezzo fabricates micro tube heat exchangers for a variety of applications, including aerospace, automotive racing, Department of Defense ground vehicles,...

  20. Heat exchangers in regenerative gas turbine cycles

    Science.gov (United States)

    Nina, M. N. R.; Aguas, M. P. N.

    1985-09-01

    Advances in compact heat exchanger design and fabrication together with fuel cost rises continuously improve the attractability of regenerative gas turbine helicopter engines. In this study cycle parameters aiming at reduced specific fuel consumption and increased payload or mission range, have been optimized together with heat exchanger type and size. The discussion is based on a typical mission for an attack helicopter in the 900 kw power class. A range of heat exchangers is studied to define the most favorable geometry in terms of lower fuel consumption and minimum engine plus fuel weight. Heat exchanger volume, frontal area ratio and pressure drop effect on cycle efficiency are considered.

  1. High temperature heat exchange: nuclear process heat applications

    International Nuclear Information System (INIS)

    The unique element of the HTGR system is the high-temperature operation and the need for heat exchanger equipment to transfer nuclear heat from the reactor to the process application. This paper discusses the potential applications of the HTGR in both synthetic fuel production and nuclear steel making and presents the design considerations for the high-temperature heat exchanger equipment

  2. Optimization of heat exchanger for indirectly heated water heater

    Directory of Open Access Journals (Sweden)

    Kaduchová Katarína

    2012-04-01

    Full Text Available Due to the optimization of geometrical parameters of the heat exchanger in indirect heated water heaters created a mathematical model of heating hot water, by which I have subsequently made the simulation of the device to change its geometrical parameters. Based on these results, the impacts of the geometrical parameters affect the performance of the heat exchanger. The results of the optimization to create a CFD model which watched at the behavior of optimized heat exchanger for indirect heated water heaters.

  3. Conjugate heat and mass transfer in heat mass exchanger ducts

    CERN Document Server

    Zhang, Li-Zhi

    2013-01-01

    Conjugate Heat and Mass Transfer in Heat Mass Exchanger Ducts bridges the gap between fundamentals and recent discoveries, making it a valuable tool for anyone looking to expand their knowledge of heat exchangers. The first book on the market to cover conjugate heat and mass transfer in heat exchangers, author Li-Zhi Zhang goes beyond the basics to cover recent advancements in equipment for energy use and environmental control (such as heat and moisture recovery ventilators, hollow fiber membrane modules for humidification/dehumidification, membrane modules for air purification, desi

  4. Heat exchanger network retrofit optimization involving heat transfer enhancement

    International Nuclear Information System (INIS)

    Heat exchanger network retrofit plays an important role in energy saving in process industry. Many design methods for the retrofit of heat exchanger networks have been proposed during the last three decades. Conventional retrofit methods rely heavily on topology modifications which often result in a long retrofit duration and high initial costs. Moreover, the addition of extra surface area to the heat exchanger can prove difficult due to topology, safety and downtime constraints. Both of these problems can be avoided through the use of heat transfer enhancement in heat exchanger network retrofit. This paper presents a novel design approach to solve heat exchanger network retrofit problems based on heat transfer enhancement. An optimisation method based on simulated annealing has been developed to find the appropriate heat exchangers to be enhanced and to calculate the level of enhancement required. The physical insight of enhanced exchangers is also analysed. The new methodology allows several possible retrofit strategies using different retrofit methods be determined. Comparison of these retrofit strategies demonstrates that retrofit modification duration and payback time are reduced when heat transfer enhancement is utilised. Heat transfer enhancement can be also used as a substitute for increased heat exchanger network surface area to reduce retrofit investment costs.

  5. Optimization of parameters of heat exchangers vehicles

    Directory of Open Access Journals (Sweden)

    Andrei MELEKHIN

    2014-09-01

    Full Text Available The relevance of the topic due to the decision of problems of the economy of resources in heating systems of vehicles. To solve this problem we have developed an integrated method of research, which allows to solve tasks on optimization of parameters of heat exchangers vehicles. This method decides multicriteria optimization problem with the program nonlinear optimization on the basis of software with the introduction of an array of temperatures obtained using thermography. The authors have developed a mathematical model of process of heat exchange in heat exchange surfaces of apparatuses with the solution of multicriteria optimization problem and check its adequacy to the experimental stand in the visualization of thermal fields, an optimal range of managed parameters influencing the process of heat exchange with minimal metal consumption and the maximum heat output fin heat exchanger, the regularities of heat exchange process with getting generalizing dependencies distribution of temperature on the heat-release surface of the heat exchanger vehicles, defined convergence of the results of research in the calculation on the basis of theoretical dependencies and solving mathematical model.

  6. Heat exchange fluids and techniques. [US patents

    Energy Technology Data Exchange (ETDEWEB)

    Ranney, M.W.

    1979-01-01

    The detailed, descriptive information presented is based on US patents, issued since January 1975, that deal with heat exchange fluids and techniques, and their potential for energy saving. This book serves a double purpose in that it supplies detailed technical information and can be used as a guide to the US patent literature in this field. By indicating all the information that is significant, and eliminating legal jargon and juristic phraseology, an advanced, technically oriented review of heat exchange fluids and techniques is presented. Information is included on the design and construction of heat exchangers; heat transfer fluids; low temperature processes; heat storage; heat transfer control in buildings; solar and geothermal energy processes; and industrial, medical, and residential uses of heat exchangers. (LCL)

  7. Heat Exchanger Lab for Chemical Engineering Undergraduates

    Science.gov (United States)

    Rajala, Jonathan W.; Evans, Edward A.; Chase, George G.

    2015-01-01

    Third year chemical engineering undergraduate students at The University of Akron designed and fabricated a heat exchanger for a stirred tank as part of a Chemical Engineering Laboratory course. The heat exchanger portion of this course was three weeks of the fifteen week long semester. Students applied concepts of scale-up and dimensional…

  8. Tube in-shell heat exchanger

    International Nuclear Information System (INIS)

    A tube-in-shell heat exchanger is described. It comprises a bundle of heat exchange tubes extending within an elongate shell. The tubes pass through a tube sheet and are connected thereto by means comprising branch pipes and compression pipe couplings

  9. Experimental evaluation of vibrations in heat exchangers

    International Nuclear Information System (INIS)

    Flow induced vibrations may produce damage of heat exchangers, condensers and steam generators tubes. To evaluate this problem a set of tests were developed to know the real support state of the tubes, which have great influence on the vibration response. This paper include a description of the tests and the results obtained applying them on a heat exchanger equipment. (author)

  10. Cryogenic heat exchanger with turbulent flows

    International Nuclear Information System (INIS)

    An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N2 and He gases from room temperatures. We present first the experimental results of various parameters which characterize the heat exchanger (efficiency, number of transfer units, heat exchange coefficient, etc) as a function of the mass flow rate of the gas to be cooled. An analysis of the Nu-Re diagram is also presented. All experiments were conducted with N2 gas. The scope of this tool is readily extended to research purposes. (paper)

  11. High temperature alloys and ceramic heat exchanger

    International Nuclear Information System (INIS)

    From the standpoint of energy saving, the future operating temperatures of process heat and gas turbine plants will become higher. For this purpose, ceramics is the most promissing candidate material in strength for application to high-temperature heat exchangers. This report deals with a servey of characteristics of several high-temperature metallic materials and ceramics as temperature-resistant materials; including a servey of the state-of-the-art of ceramic heat exchanger technologies developed outside of Japan, and a study of their application to the intermediate heat exchanger of VHTR (a very-high-temperature gas-cooled reactor). (author)

  12. Testing and plugging power plant heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Sutor, F. [Expando Seal Tools, Inc., Montgomeryville, PA (United States)

    1994-12-31

    Heat Exchanger tubes fail for any number of reasons including but certainly not limited to the cumulative effects of corrosion, erosion, thermal stress and fatigue. This presentation will attempt to identify the most common techniques for determining which tubes are leaking and then introduce the products in use to plug the leaking tubes. For the sake of time I will limit the scope of this presentation to include feedwater heaters and secondary system heat exchangers such as Hydrogen Coolers, Lube Oil Coolers, and nuclear Component Cooling Water, Emergency Cooling Water, Regenerative Heat Recovery heat exchangers.

  13. Heat transfer analysis of short helical borehole heat exchangers

    International Nuclear Information System (INIS)

    Highlights: ► Vertical ground heat exchanger with a helical shaped pipe is analyzed. ► The model considers the interaction between the ground and the environment. ► The results of the model are in good agreement with the experimental values. ► The weather conditions considerably affect the fluid heat carrier temperature. ► The pitch between the turns does not affect the behaviour of the heat exchanger. -- Abstract: In this paper a numerical model to analyze the thermal behaviour of vertical ground heat exchangers with a helical shaped pipe is presented. This type of configuration can be a suitable alternative to conventional ground heat exchangers, especially when the heating and cooling loads of the building are very low. The model describes the heat transfer problem by means of a network of interconnected thermal resistances and capacitances. Moreover, as the investigated ground heat exchanger is usually installed in shallow depth, the model takes into account the interaction between the ground and the ambient environment which affects the fluid heat carrier temperature into the heat exchanger and, as a consequence, the energy efficiency of the heat pump. After a sensitivity analysis on the mesh parameters, the presented model is compared with experimental data and the simulation results show good agreement with the measurements. Finally, analyses to investigate the influence of the weather conditions, of the axial heat transfer and of the pitch between the turns of the helical pipe for two types of ground are carried out.

  14. Component Cooling Heat Exchanger Heat Transfer Capability Operability Monitoring

    International Nuclear Information System (INIS)

    The ultimate heat sink (UHS) is of highest importance for nuclear power plant safe and reliable operation. The most important component in line from safety-related heat sources to the ultimate heat sink water body is a component cooling heat exchanger (CC Heat Exchanger). The Component Cooling Heat Exchanger has a safety-related function to transfer the heat from the Component Cooling (CC) water system to the Service Water (SW) system. SW systems throughout the world have been the root of many plant problems because the water source, usually river, lake, sea or cooling pond, are conductive to corrosion, erosion, biofouling, debris intrusion, silt, sediment deposits, etc. At Krsko NPP, these problems usually cumulate in the summer period from July to August, with higher Sava River (service water system) temperatures. Therefore it was necessary to continuously evaluate the CC Heat Exchanger operation and confirm that the system would perform its intended function in accordance with the plant's design basis, given as a minimum heat transfer rate in the heat exchanger design specification sheet. The Essential Service Water system at Krsko NPP is an open cycle cooling system which transfers heat from safety and non-safety-related systems and components to the ultimate heat sink the Sava River. The system is continuously in operation in all modes of plant operation, including plant shutdown and refueling. However, due to the Sava River impurities and our limited abilities of the water treatment, the system is subject to fouling, sedimentation buildup, corrosion and scale formation, which could negatively impact its performance being unable to satisfy its safety related post accident heat removal function. Low temperature difference and high fluid flows make it difficult to evaluate the CC Heat Exchanger due to its specific design. The important effects noted are measurement uncertainties, nonspecific construction, high heat transfer capacity, and operational specifics (e.g. using CC Heat Exchanger bypass valves for CC temperature control, variation of plant heat loads, pumps performance, and day-night temperature difference, with lagging effects on heat transfer dynamics). Krsko NPP is continuously monitoring the Component Cooling (CC) Heat Exchanger performance using the on-line process information system (PIS). By defining the mathematical algorithm, it is possible to continuously evaluate the CC Heat Exchanger operability by verifying if the heat transfer rate calculation is in accordance with the heat exchanger design specification sheet requirements. These calculations are limited to summer periods only when the bypass valves are neither throttled nor open.(author).

  15. Heat exchanger device and method for heat removal or transfer

    Energy Technology Data Exchange (ETDEWEB)

    Koplow, Jeffrey P

    2015-03-24

    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  16. Heat exchanger device and method for heat removal or transfer

    Science.gov (United States)

    Koplow, Jeffrey P.

    2015-12-08

    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  17. Heat exchanger device and method for heat removal or transfer

    Science.gov (United States)

    Koplow, Jeffrey P

    2013-12-10

    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  18. Performances of heat exchangers on HTGR application

    International Nuclear Information System (INIS)

    Rising oil price is making the high-temperature gas-cooled reactor (HTGR) an attractive alternative energy resource for high temperature process heat applications. Motivation and aspect of nuclear process applications to steam reforming and coal gasification, etc. are described. Studies on heat transfer problems are reviewed. The present status of designed high temperature heat exchangers is summarized. The performances of He-He high temperature heat exchanger tested in Japan is reported. Several problems in the future research and development of technologies for process heat application by HTGR are discussed. 29 refs

  19. Heat exchanger, head and shell acceptance criteria

    International Nuclear Information System (INIS)

    Instability of postulated flaws in the head component of the heat exchanger could not produce a large break, equivalent to a DEGB in the PWS piping, due to the configuration of the head and restraint provided by the staybolts. Rather, leakage from throughwall flaws in the head would increase with flaw length with finite leakage areas that are bounded by a post-instability flaw configuration. Postulated flaws at instability in the shell of the heat exchanger or in the cooling water nozzles could produce a large break in the Cooling Water System (CWS) pressure boundary. An initial analysis of flaw stability for postulated flaws in the heat exchanger head was performed in January 1992. This present report updates that analysis and, additionally, provides acceptable flaw configurations to maintain defined structural or safety margins against flaw instability of the external pressure boundary components of the heat exchanger, namely the head, shell, and cooling water nozzles. Structural and flaw stability analyses of the heat exchanger tubes, the internal pressure boundary of the heat exchangers or interface boundary between the PWS and CWS, were previously completed in February 1992 as part of the heat exchanger restart evaluation and are not covered in this report

  20. Thermodynamic Optimization of GSHPS Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Ahmad Kahrobaeian

    2007-09-01

    Full Text Available

    In this paper, a new method for determining the optimized dimensions of a ground source heat pump system (GSHPS heat exchanger is presented. Using the GSHPS is one of the ways for utilization of infinite, clean and renewable energies in the environment. In recent years, due to limitation of physical space for installing the heat exchangers and avoiding the environmental effects on heat exchanger operation, vertical GSHP systems are used more than the other ones. Determination of optimum heat exchanger size is one of the most important parameters in the optimization of the heat exchanger design. In this study, optimum length and diameter for the heat exchanger is determined for different mass flows by using the second law of thermodynamics. The optimal length and diameter minimize entropy generation and therefore result in increased efficiency of the heat pump.

    • An initial version of this pa per was published in May of 2004 in the proceedings of Second International Applied Thermodynamics Conference, Istanbul, Turkey.

  1. A Review on Heat Transfer Improvent of Plate Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Abhishek Nandan

    2015-03-01

    Full Text Available Plate heat exchanger has found a wide range of application in various industries like food industries, chemical industries, power plants etc. It reduces the wastage of energy and improves the overall efficiency of the system. Hence, it must be designed to obtain the maximum heat transfer possible. This paper is presented in order to study the various theories and results given over the improvement of heat transfer performance in a plate heat exchanger. However, there is still a lack in data and generalized equations for the calculation of different parameters in the heat exchanger. It requires more attention to find out various possible correlations and generalized solutions for the performance improvement of plate heat exchanger.

  2. Heat Exchanger Support Bracket Design Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Rucinski, Russ; /Fermilab

    1995-01-12

    This engineering note documents the design of the heat exchanger support brackets. The heat exchanger is roughly 40 feet long, 22 inches in diameter and weighs 6750 pounds. It will be mounted on two identical support brackets that are anchored to a concrete wall. The design calculations were done for one bracket supporting the full weight of the heat exchanger, rounded up to 6800 pounds. The design follows the American Institute of Steel Construction (AISC) Manual of steel construction, Eighth edition. All calculated stresses and loads on welds were below allowables.

  3. Heat exchanger module for secondary circuit of nuclear heating plant

    International Nuclear Information System (INIS)

    The heat exchanger placed in the reactor vessel consists of a bundle of heat exchange tubes, two tube plates, their lids, and inlet and outlet tubes. The heat exchange tubes of the exchanger of the secondary coolant circuit are attached by their upper ends to the upper tube plate and by their bottom ends to the bottom tube plate. The heat exchange elements are placed around the inlet tube of the secondary coolant circuit passing tightly through the upper tube plate. The outlet tube of the secondary coolant circuit passes tightly through the reactor vessel and by its upper end is attached to the inlet tube and by its bottom end to the lid of the upper tube plate. The inlet tube is tightly connected to the bottom tube plate via the expansion pressurizer. (B.S.)

  4. A heat exchanger with dual tubes

    International Nuclear Information System (INIS)

    The invention relates to a heat exchanger provided with dual tubes arranged in two bundles within a casing. That heat exchanger is characterized in that the tubes penetrate into the casing from the opposite ends thereof, said tubes being imbricated in such a way of the second bundle, a heat-conducting medium being contained in said casing for transferring heat from the fluid of one of said bundles to the other bundle fluid. The invention can be applied in particular to liquid-metal steam generators and also extended to PWR reactors

  5. Lightweight Thermal Storage Heat Exchangers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR proposal aims to develop thermal energy storage heat exchangers that are significantly lighter and higher conductance than the present art which involves...

  6. Comparative Study of Heat Exchangers Using CFD

    Directory of Open Access Journals (Sweden)

    Melvinraj C R

    2014-05-01

    Full Text Available A parallel flow heat exchanger and a corresponding ribbed tube heat exchanger is modeled and numerically analysed using a commercial finite volume CFD package. Pro-E & ANSYS 14.5 softwares are used for the designing and the analysis. CFD predictions of effectiveness of the two heat exchangers are obtained and compared. After selecting the best modeling approach, the sensitivity of the results to particular flow rate is investigated. It is observed that the flow and the temperature fields obtained from CFD simulations provide valuable information about the parts of the heat exchanger design that need improvement. Correlation based approaches may indicate the existence of the weakness but CFD simulations can also pin point the source and the location of it. Using CFD may speed up the design process and may improve the final design.

  7. Acoustic resonance in plate heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Rodarte, Enrique; Miller, Norman; Hrnjak, Predrag [Illinois Univ., Mechanical and Industrial Engineering Dept., Urbana, IL (United States)

    1998-12-01

    A `whistling` sound, which develops under transient conditions in some automobile air conditioning systems equipped with plate type evaporators, was identified as acoustic resonance. The `whistle` was reproduced in the laboratory under steady-state conditions. Testing of these heat exchangers was done first with R134a and then with nitrogen. Nitrogen testing proved to be much faster and easier and provided results comparable to the results obtained using R134a. The evidence presented in this work suggests the acoustic resonance in this type of heat exchanger is similar in nature to the acoustic resonance problems reported for tube array in duct type heat exchangers. This is to the authors` knowledge the first time that acoustic resonance problems have been reported in the literature for plate heat exchangers. (Author)

  8. Aplicación del Método de la Colonia de Hormigas Mixto a la optimización de intercambiadores de calor de tubo y coraza//Application of the Mixed Ant Colony Method to the optimization of tube and shell heat exchangers

    Directory of Open Access Journals (Sweden)

    Maida Bárbara Reyes‐Rodríguez

    2014-05-01

    Full Text Available Los procesos de transferencia de calor sonuno de los problemas más importantes a resolver en el campo de la Ingeniería. Entre los equipos más usados en la industria para realizar la transferencia de calor están los intercambiadores de calor de tubo y coraza. En el presente trabajo se desarrolla el procedimiento para la optimización del diseño de estos equipos utilizando el método de Kern y aplicando el algoritmo de la colonia de hormigas. Se aplica el mismo a tres ejemplos concretos y los resultados obtenidos se comparan con los obtenidos aplicando otros métodos de la inteligencia artificial. Se optimizan los principales parámetros geométricos de los intercambiadores de calor de tubo y coraza para lograr un menor costo de los mismos. Se demuestra la eficacia del nuevo procedimiento MACO (Mixed Ant Colony Optimization, en el proceso de optimización desde el punto de vista económico utilizando diferentes casos de estudios.Palabras claves: intercambiadores de calor, colonia de hormigas, método de Kern.______________________________________________________________________________AbstractHeat transfer processes are one of the most important problems to be solved in the field of Engineering. Among the most widely used equipment for heat transfer in the industry are the shell and tube heat exchangers. This paper develops the procedure for optimizing the design of shell and tube heat exchangers using the method of Kern and applying the ant colony algorithm. The procedure has been applied to three specific examples and the results obtained are compared with those obtained by applying other methods of artificial intelligence. The main geometric parameters of shell and tube heat exchangers are optimized, to achieve a lower cost of the exchanger. The efficacy of the new procedure MACO (Mixed Ant Colony Optimization for the optimization process from economically point of view was demonstrated, using different case studies.Key words: heat exchangers, ant colony, Kern method.

  9. Stirling Engine With Radial Flow Heat Exchangers

    Science.gov (United States)

    Vitale, N.; Yarr, George

    1993-01-01

    Conflict between thermodynamical and structural requirements resolved. In Stirling engine of new cylindrical configuration, regenerator and acceptor and rejector heat exchangers channel flow of working gas in radial direction. Isotherms in regenerator ideally concentric cylinders, and gradient of temperature across regenerator radial rather than axial. Acceptor and rejector heat exchangers located radially inward and outward of regenerator, respectively. Enables substantial increase in power of engine without corresponding increase in diameter of pressure vessel.

  10. Heat transfer from oriented heat exchange areas

    Science.gov (United States)

    Vantuch, Martin; Huzvar, Jozef; Kapjor, Andrej

    2014-03-01

    This paper deals with the transfer of heat-driven heat transfer surface area in relation to the construction of the criterion equation for "n" horizontal pipe one about another. On the bases of theoretical models have been developed for calculating the thermal performance of natural convection by Churilla and Morgan, for various pipe diameters and temperatures. These models were compared with models created in CFD-Fluent Ansys the same boundary conditions. The aim of the analyse of heat and fluxional pipe fields "n" pipes one about another at natural convection is the creation of criterion equation on the basis of which the heat output of heat transfer from pipe oriented areas one above another with given spacing could be quantified. At presence a sum of criterion equations exists for simple geometrical shapes of individual oriented geometrical areas but the criterion equation which would consider interaction of fluxional field generated by free convection from multiple oriented areas is not mentioned in standardly accessible technical literature and other magazine publications.

  11. Method for removing coronene from heat exchangers

    International Nuclear Information System (INIS)

    A method for removing a coronene deposit in a reforming process is described that consists of (A) contacting a hydrocarbonacous feedstock with a catalyst in the presence of added hydrogen at reforming conditions in a reforming zone; (B) splitting the total reforming zone effluent into a first stream and a second stream; (C) passing said first stream into a first train of heat exchangers arranged in parallel with a second train of heat exchangers; (D) passing said second stream into said second train of heat exchangers, said reforming zone effluent comprising coronene, at least a portion of which deposits in said heateexchangers; (E) separating the heat exchanged total reforming zone effluent into a hydrogen-rich gaseous phase and a liquid hydrocarbon phase comprising normally liquid hydrocarbons and normally gaseous hydrocarbons, the improvement which comprises reducing the flow of said first stream in said first train of heat exchangers to produce a temperature sufficient to condense at least a portion of said reformer effluent therein such that the resulting condensate contacts said coronene deposit, and simultaneously increasing the flow of said second stream in said second train of heat exchangers

  12. Brayton-cycle heat exchanger technology program

    Science.gov (United States)

    Killackey, J. J.; Coombs, M. G.; Graves, R. F.; Morse, C. J.

    1976-01-01

    The following five tasks designed to advance this development of heat exchanger systems for close loop Brayton cycle power systems are presented: (1) heat transfer and pressure drop data for a finned tubular heat transfer matrix. The tubes are arranged in a triangular array with copper stainless steel laminate strips helically wound on the tubes to form a disk fin geometry; (2) the development of a modularized waste heat exchanger. Means to provide verified double containment are described; (3) the design, fabrication, and test of compact plate fin heat exchangers representative of full scale Brayton cycle recuperators; (4) the analysis and design of bellows suitable for operation at 1600 F and 200 psia for 1,000 cycles and 50,000 hours creep life; and (5) screening tests used to select a low cost braze alloy with the desirable attributes of a gold base alloy. A total of 22 different alloys were investigated; the final selection was Nicrobraz 30.

  13. REVIEW OF HEAT TRANSFER ENHANCEMENT IN DIFFERENT TYPES OF BAFFLES AND THEIR ORIENTATIONS.

    Directory of Open Access Journals (Sweden)

    S.P.WALDE

    2012-04-01

    Full Text Available The use of baffles in channel is commonly used for passive heat transfer enhancement strategy in single phase internal flow. Considering the rapid increase in energy demand, effective heat transfer enhancement techniques have become important task worldwide. Some of the applications of passive heat transfer enhancement strategies are in process industries, thermal regenerator, Shell and tube type heat exchanger, Internal cooling system of gas turbine blades, radiators for space vehicles and automobiles, etc. Thepresent paper is a review of different types of baffles and its arrangement. According to recent studies these are known to be economic heat transfer augmentation tools.

  14. Flow and heat transfer enhancement in tube heat exchangers

    Science.gov (United States)

    Sayed Ahmed, Sayed Ahmed E.; Mesalhy, Osama M.; Abdelatief, Mohamed A.

    2015-11-01

    The performance of heat exchangers can be improved to perform a certain heat-transfer duty by heat transfer enhancement techniques. Enhancement techniques can be divided into two categories: passive and active. Active methods require external power, such as electric or acoustic field, mechanical devices, or surface vibration, whereas passive methods do not require external power but make use of a special surface geometry or fluid additive which cause heat transfer enhancement. The majority of commercially interesting enhancement techniques are passive ones. This paper presents a review of published works on the characteristics of heat transfer and flow in finned tube heat exchangers of the existing patterns. The review considers plain, louvered, slit, wavy, annular, longitudinal, and serrated fins. This review can be indicated by the status of the research in this area which is important. The comparison of finned tubes heat exchangers shows that those with slit, plain, and wavy finned tubes have the highest values of area goodness factor while the heat exchanger with annular fin shows the lowest. A better heat transfer coefficient ha is found for a heat exchanger with louvered finned and thus should be regarded as the most efficient one, at fixed pumping power per heat transfer area. This study points out that although numerous studies have been conducted on the characteristics of flow and heat transfer in round, elliptical, and flat tubes, studies on some types of streamlined-tubes shapes are limited, especially on wing-shaped tubes (Sayed Ahmed et al. in Heat Mass Transf 50: 1091-1102, 2014; in Heat Mass Transf 51: 1001-1016, 2015). It is recommended that further detailed studies via numerical simulations and/or experimental investigations should be carried out, in the future, to put further insight to these fin designs.

  15. Flow and heat transfer enhancement in tube heat exchangers

    Science.gov (United States)

    Sayed Ahmed, Sayed Ahmed E.; Mesalhy, Osama M.; Abdelatief, Mohamed A.

    2015-08-01

    The performance of heat exchangers can be improved to perform a certain heat-transfer duty by heat transfer enhancement techniques. Enhancement techniques can be divided into two categories: passive and active. Active methods require external power, such as electric or acoustic field, mechanical devices, or surface vibration, whereas passive methods do not require external power but make use of a special surface geometry or fluid additive which cause heat transfer enhancement. The majority of commercially interesting enhancement techniques are passive ones. This paper presents a review of published works on the characteristics of heat transfer and flow in finned tube heat exchangers of the existing patterns. The review considers plain, louvered, slit, wavy, annular, longitudinal, and serrated fins. This review can be indicated by the status of the research in this area which is important. The comparison of finned tubes heat exchangers shows that those with slit, plain, and wavy finned tubes have the highest values of area goodness factor while the heat exchanger with annular fin shows the lowest. A better heat transfer coefficient ha is found for a heat exchanger with louvered finned and thus should be regarded as the most efficient one, at fixed pumping power per heat transfer area. This study points out that although numerous studies have been conducted on the characteristics of flow and heat transfer in round, elliptical, and flat tubes, studies on some types of streamlined-tubes shapes are limited, especially on wing-shaped tubes (Sayed Ahmed et al. in Heat Mass Transf 50: 1091-1102, 2014; in Heat Mass Transf 51: 1001-1016, 2015). It is recommended that further detailed studies via numerical simulations and/or experimental investigations should be carried out, in the future, to put further insight to these fin designs.

  16. Research of heat exchange rate of the pulsating heat pipe

    Directory of Open Access Journals (Sweden)

    Kravets V. Yu.

    2010-02-01

    Full Text Available Given article presents experimental research of heat transfer characteristics of the pulsating heat pipe (PHP which consists of seven coils with 1 mm inner diameter. Water was used as the heat carrier. PHP construction, measuring circuit and research technique are presented. It is shown that under PHP functioning there are two characteristic modes of operation, which can be distinguished by values of thermal resistance. PHP heat exchange features are disclosed.

  17. The water-cryogen heat exchanger

    Science.gov (United States)

    Bartlit, J. R.; Boyer, K.; Williamson, K. D.

    1970-01-01

    Heat exchanger, using water as heat medium, converts liquid hydrogen to gaseous hydrogen at a very high rate. Possible applications include treatment of liquified natural gas in cities to bring the gas on-line quickly, conversion of liquid oxygen and liquid nitrogen for steel mills, and high volume inert purging.

  18. Phase Change Material Heat Exchanger Life Test

    Science.gov (United States)

    Lillibridge, Sean; Stephan, Ryan

    2009-01-01

    Low Lunar Orbit (LLO) poses unique thermal challenges for the orbiting space craft, particularly regarding the performance of the radiators. The IR environment of the space craft varies drastically from the light side to the dark side of the moon. The result is a situation where a radiator sized for the maximal heat load in the most adverse situation is subject to freezing on the dark side of the orbit. One solution to this problem is to implement Phase Change Material (PCM) Heat Exchangers. PCM Heat Exchangers act as a "thermal capacitor," storing thermal energy when there is too much being produced by the space craft to reject to space, and then feeding that energy back into the thermal loop when conditions are more favorable. Because they do not use an expendable resource, such as the feed water used by sublimators and evaporators, PCM Heat Exchangers are ideal for long duration LLO missions. In order to validate the performance of PCM Heat Exchangers, a life test is being conducted on four n-Pentadecane, carbon filament heat exchangers. Fluid loop performance, repeatability, and measurement of performance degradation over 2500 melt-freeze cycles will be performed.

  19. Borehole Heat Exchangers; Intercambiadores goetermicos verticales

    Energy Technology Data Exchange (ETDEWEB)

    Llopis Trillo, G.; Lopez Jimeno, C.

    2009-07-01

    Ground source heat pump systems are applied to air conditioning and domestic hot water in buildings for its high energetic efficiency. In urban areas of major European countries, the most commonly used are those, that include borehole heat exchangers. Their use in Spain, compared with its surrounding countries is quite small. Here it is described their functioning system, their advantages over other geothermal heat exchangers, their equipment and materials used in their construction their means of thermal transfer, and it is done a prediction about the future of their use in our country. (Author)

  20. Heat transfer 1982; Proceedings of the Seventh International Conference, Technische Universitaet Muenchen, Munich, West Germany, September 6-10, 1982. Volume 6 - General papers: Combined heat and mass transfer, particle heat transfer, heat exchangers, industrial heat transfer, heat transfer in energy utilization

    Science.gov (United States)

    Grigull, U.; Hahne, E.; Stephan, K.; Straub, J.

    Laboratory and operational studies of heat transfer (HT) are presented. Such topics as the irreversibility of HT and mass transfer (MT), HT in disperse systems at high temperatures, fixed-bed reactors with submerged tube bundles, HT and MT in a low-speed turbulent boundary layer with condensation, multilayer insulation blankets for spacecraft applications, HT and MT in transpiration-cooled turbine blades, and finite-element analysis of HT in a solid with radiation and ablation are discussed. Contributions are included on the design of shell-and-tube heat exchangers to avoid flow-induced vibration, HT and MT in air-conditioning cooling coils, a friction-factor correlation for the offset strip-fin matrix, convective HT in gas-turbine combustion chambers, thermal-energy storage systems, turbulent buoyant HT in enclosures containing fire sources, a phase-change dry/wet cooling system for power plants, and the effect of secondary flow on HT in solar collector tubes. For individual items see A83-43014 to A83-43024

  1. Thermal hydraulic simulation of moderator heat exchanger

    International Nuclear Information System (INIS)

    Pressurized heavy water reactors form the majority in the first stage of India's nuclear power programme. Heavy water is both moderator and primary coolant. The heat generated in the moderator due to neutron moderation and capture has to be removed in moderator heat exchangers. It has been desired to improve the performance characteristics of moderator heat exchangers, whereby moderator would enter the calandria vessel at a low temperature and would enable higher power of operation for the same limiting temperature of moderator in the calandria. Results of studies carried out using a three dimensional computer code for various operating options are given. Using these velocities the heat exchangers have been analysed for flow induced vibrations. 7 refs., 6 figs., 6 tabs

  2. The effect of plate heat exchanger’s geometry on heat transfer

    OpenAIRE

    Oana GIURGIU; Angela PLE?A; Dan OPRU?A

    2014-01-01

    The study presents further Computational Fluid Dynamics (CFD) numerical analysis for two models of plate heat exchangers. Comparatively was studied the influence of geometric characteristics of plates on the intensification process of heat exchange. For this purpose, it was examined the distribution of velocity and temperatures fields on active plate height. Heat transfer characteristics were analysed through the variation of mass flow on the primary heat agent.

  3. The effect of plate heat exchanger’s geometry on heat transfer

    Directory of Open Access Journals (Sweden)

    Oana GIURGIU

    2014-11-01

    Full Text Available The study presents further Computational Fluid Dynamics (CFD numerical analysis for two models of plate heat exchangers. Comparatively was studied the influence of geometric characteristics of plates on the intensification process of heat exchange. For this purpose, it was examined the distribution of velocity and temperatures fields on active plate height. Heat transfer characteristics were analysed through the variation of mass flow on the primary heat agent.

  4. Near Field Investigation of Borehole Heat Exchangers

    OpenAIRE

    Erol, Selcuk

    2015-01-01

    As an alternative and renewable energy source, the shallow geothermal energy evolving as one of the most popular energy source due to its easy accessibility and availability worldwide, and the ground source heat pump (GSHP) systems are the most frequent applications for extracting the energy from the shallow subsurface. As the heat extraction capacity of the GSHP system applications arises, the design of the borehole heat exchangers (BHE), which is the connected part of the system in the grou...

  5. Performance Investigation of Plate Type Heat Exchanger (A Case Study)

    OpenAIRE

    Simarpreet Singh; Sanjeev Jakhar

    2014-01-01

    Heat exchanger is a thermodynamic system which is most commonly used in the process industry for exchanging heat energy between the fluids. flowing in the same or opposite direction. It is desired that effectiveness of heat exchanger should remain as large as possible. Heat exchanger's performance may be improved by the addition of fins or corrugations. These investigations include design of plate type heat exchanger, heat transfer enhancement, flow phenomenon and cleanliness ...

  6. Design of common heat exchanger network for batch processes

    International Nuclear Information System (INIS)

    Heat integration of energy streams is very important for the efficient energy recovery in production systems. Pinch technology is a very useful tool for heat integration and maximizing energy efficiency. Creating of heat exchangers network as a common solution for systems in batch mode that will be applicable in all existing time slices is very difficult. This paper suggests a new methodology for design of common heat exchanger network for batch processes. Heat exchanger network designs were created for all determined repeatable and non-repeatable time periods – time slices. They are the basis for creating the common heat exchanger network. The common heat exchanger network as solution, satisfies all heat-transfer needs for each time period and for every existing combination of selected streams in the production process. This methodology use split of some heat exchangers into two or more heat exchange units or heat exchange zones. The reason for that is the multipurpose use of heat exchangers between different pairs of streams in different time periods. Splitting of large heat exchangers would maximize the total heat transfer usage of heat exchange units. Final solution contains heat exchangers with the minimum heat load as well as the minimum need of heat transfer area. The solution is applicable for all determined time periods and all existing stream combinations. - Highlights: •Methodology for design of energy efficient systems in batch processes. •Common Heat Exchanger Network solution based on designs with Pinch technology. •Multipurpose use of heat exchangers in batch processes

  7. Research of characteristics slot-hole heat exchanger with the developed surface of heat exchange

    Directory of Open Access Journals (Sweden)

    Malkin E. C.

    2010-03-01

    Full Text Available Thermal characteristics of multichannel slot-hole heat exchanger with the developed surface of heat exchange inside the opened-cycle water cooling system are experimentally investigated. Graphic dependences of average value of temperature of the simulator of a heat current and temperatures of the heat exchanger base are presented on tapped-off power. Dependences of tapped-off power and hydraulic losses on the of water consumption are given. It is shown, that use of developed slot-hole heat exchanger provides higher values of tapped-off power as compared to well-known two-channel slot-hole heat exchanger: at the temperature of heat-generating component simulator of +60°С the tapped-off power increases with 307 up to 750 W. Recommendations on increase of adaptability of slot-hole heat exchanger manufacturing are given. Heat exchanger is suitable for application in microprocessors and others heat-generating components and electronic equipment units cooling.

  8. Microtube strip heat exchanger. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Doty, F.D.

    1992-07-09

    The purpose of this contract has been to explore the limits of miniaturization of heat exchangers with the goals of (1) improving the theoretical understanding of laminar heat exchangers, (2) evaluating various manufacturing difficulties, and (3) identifying major applications for the technology. A low-cost, ultra-compact heat exchanger could have an enormous impact on industry in the areas of cryocoolers and energy conversion. Compact cryocoolers based on the reverse Brayton cycle (RBC) would become practical with the availability of compact heat exchangers. Many experts believe that hardware advances in personal computer technology will rapidly slow down in four to six years unless lowcost, portable cryocoolers suitable for the desktop supercomputer can be developed. Compact refrigeration systems would permit dramatic advances in high-performance computer work stations with ``conventional`` microprocessors operating at 150 K, and especially with low-cost cryocoolers below 77 K. NASA has also expressed strong interest in our MTS exchanger for space-based RBC cryocoolers for sensor cooling. We have demonstrated feasibility of higher specific conductance by a factor of five than any other work in high-temperature gas-to-gas exchangers. These laminar-flow, microtube exchangers exhibit extremely low pressure drop compared to alternative compact designs under similar conditions because of their much shorter flow length and larger total flow area for lower flow velocities. The design appears to be amenable to mass production techniques, but considerable process development remains. The reduction in materials usage and the improved heat exchanger performance promise to be of enormous significance in advanced engine designs and in cryogenics.

  9. 21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

    Science.gov (United States)

    2010-04-01

    ... bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of a heat exchange system used in extracorporeal circulation to warm or cool the blood or... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass heat exchanger....

  10. Comparison between conventional heat exchanger performance and an heat pipes exchanger

    International Nuclear Information System (INIS)

    The thermal performance of conventional compact heat exchanger and of exchanger with heat pipes are simulated using a digital computer, for equal volumes and the same process conditions. The comparative analysis is depicted in graphs that indicate which of the situations each equipment is more efficient. (author)

  11. Simulation of induction heating process with radiative heat exchange

    Directory of Open Access Journals (Sweden)

    A. Kachel

    2007-05-01

    Full Text Available Purpose: Numerical modelling of induction heating process is a complex issue. It needs analysis of coupled electromagnetic and thermal fields. Calculation models for electromagnetic field analysis as well as thermal field analysis need simplifications. In case of thermal field calculations, correct modelling of radiative heat exchange between the heated charge and inductor’s thermal insulation is essential. Most commercial calculation programs enabling coupled analysis of electromagnetic and thermal fields do not allow taking into consideration radiative heat exchange between calculation model components, which limits thermal calculations only to the charge area. The paper presents a supplementation of the program Flux 2D with radiative heat exchange procedures.Design/methodology/approach: Commercial program Flux 2D designed for coupled electromagnetic and thermal calculation (based on finite element method was supplemented with authors program for radiative heat exchange based on numerical integration of classic equations.Findings: Supplementation EM-T calculations with radiative heat exchange between charge and inductor enables to calculate thermal insulation parameters and increase precision of modelling.Research limitations/implications: Procedures for radiative heat exchange enables calculation of two surfaces (flat or cylindrical with finite dimensions. The surfaces can be displaced relative to each other (charge shorter or longer than thermal insulation of inductor. Material of surfaces is modelled as: flat, diffuse, radiant surfaces absorb energy evenly in the whole spectrum (grey bodies. The whole system is modelled as in a steady thermal state (quasi-steady.Originality/value: Authors program extends Flux 2D features with a possibility for calculating radiative heat transfer. The application of radiative process is possible between all components of the studied model, not only for the boundary conditions.

  12. The dynamic behaviour of heat exchangers

    International Nuclear Information System (INIS)

    In order to study the dynamics of nuclear power plants, one needs mathematical models made up of ordinary differential equations. This report deals with models for heat exchangers. These models allow exact evaluations of the temperatures for any steady state. The deformation of the temperature maps during transients is taken into account. To do this, average temperatures are evaluated keeping In mind, on one hand the partial differential equations, on the other hand, the physical phenomenons which are involved. Seven ordinary differential equations at most, are necessary for one heat exchanger. Theses models were compared with mathematically exact ones and also with experimental results, that EDF was able to measure on EDF-1 heat exchangers. The results appear to be correct. (authors)

  13. Simulation of induction heating process with radiative heat exchange

    OpenAIRE

    Kachel, A; Przy?ucki, R.

    2007-01-01

    Purpose: Numerical modelling of induction heating process is a complex issue. It needs analysis of coupled electromagnetic and thermal fields. Calculation models for electromagnetic field analysis as well as thermal field analysis need simplifications. In case of thermal field calculations, correct modelling of radiative heat exchange between the heated charge and inductor’s thermal insulation is essential. Most commercial calculation programs enabling coupled analysis of electromagnetic and ...

  14. Heat Transfer of Nanofluid in a Double Pipe Heat Exchanger

    OpenAIRE

    Aghayari, Reza; Maddah, Heydar; Zarei, Malihe; Dehghani, Mehdi; Kaskari Mahalle, Sahar Ghanbari

    2014-01-01

    This paper investigates the enhancement of heat transfer coefficient and Nusselt number of a nanofluid containing nanoparticles (?-AL2O3) with a particle size of 20?nm and volume fraction of 0.1%–0.3% (V/V). Effects of temperature and concentration of nanoparticles on Nusselt number changes and heat transfer coefficient in a double pipe heat exchanger with counter turbulent flow are investigated. Comparison of experimental results with valid theoretical data based on semiempirical equations s...

  15. Heat recovery equipment for engines

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C.L.

    1977-04-01

    The recovery and use of waste heat from prime movers is an important consideration for evaluating an on-site power system, since it is the basic factor that makes possible a substantial increase in fuel-use efficiency. The equipment usually employed to recover waste heat can be categorized as: (a) shell-and-tube type heat exchangers, (b) radiator-type heat exchangers, (c) exhaust gas boilers for the generation of pressurized hot water and/or steam, (d) steam separators, and (e) combined packaged units for ebulliently cooled internal combustion piston engines. The functional requirements and cost considerations involved in applying these devices for the recovery of waste heat from various types of prime-movers considered for application in the ICES Systems Engineering Program are examined.

  16. Tube-in-shell heat exchangers

    International Nuclear Information System (INIS)

    A tube-in-shell heat exchanger has double sealing joints between the tubes and a tube plate of the heat exchanger constituted by the provision of a secondary tube plate spaced from the normal tube plate and through which each tube extends with sealing in addition to the normal tube to tube plate sealing joints, there being a bellows enveloping the tubes and sealed to both the normal and the secondary tube plates. The space between these tube plates can be monitored for leakage. (author)

  17. Carbon nanotube heat-exchange systems

    Science.gov (United States)

    Hendricks, Terry Joseph (Arvada, CO); Heben, Michael J. (Denver, CO)

    2008-11-11

    A carbon nanotube heat-exchange system (10) and method for producing the same. One embodiment of the carbon nanotube heat-exchange system (10) comprises a microchannel structure (24) having an inlet end (30) and an outlet end (32), the inlet end (30) providing a cooling fluid into the microchannel structure (24) and the outlet end (32) discharging the cooling fluid from the microchannel structure (24). At least one flow path (28) is defined in the microchannel structure (24), fluidically connecting the inlet end (30) to the outlet end (32) of the microchannel structure (24). A carbon nanotube structure (26) is provided in thermal contact with the microchannel structure (24), the carbon nanotube structure (26) receiving heat from the cooling fluid in the microchannel structure (24) and dissipating the heat into an external medium (19).

  18. Heat exchanger including an auxiliary cooling system

    International Nuclear Information System (INIS)

    It comprises a vertical envelope, heat transfer tubes mainted in this envelope, inlet and outlet windows for a primary coolant flowing between the tubes and inlet and outlet collectors to make the secondary coolant circulate inside the tubes, and an auxiliary cooling system situated in the inlet window, inside a shell. This shell is opened at its upper part and connected to the heat exchanger envelope at its lower part. This system cools the primary coolant when it is not in forced circulation, what creates a natural circulation of this primary coolant to the bottom. The invention can be applied to fast nuclear reactors cooled by sodium. This heat exchanger extracts the heat produced by the core operating normally, and besides, the residual power in case of pump shutdown reactor accident

  19. Fouling corrosion in aluminum heat exchangers

    OpenAIRE

    Su Jingxin; Ma Minyu; Wang Tianjing; Guo Xiaomei; Hou Liguo; Wang Zhiping

    2015-01-01

    Fouling deposits on aluminum heat exchanger reduce the heat transfer efficiency and cause corrosion to the apparatus. This study focuses on the corrosive behavior of aluminum coupons covered with a layer of artificial fouling in a humid atmosphere by their weight loss, Tafel plots, electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) observations. The results reveal that chloride is one of the major elements found in the fouling which damages the passive film a...

  20. Heat exchanger containing a component capable of discontinuous movement

    Science.gov (United States)

    Wilson, David Gordon (Winchester, MA)

    2002-01-01

    Regenerative heat exchangers are described for transferring heat between hot and cold fluids. The heat exchangers have seal-leakage rates significantly less than those of conventional regenerative heat exchangers because the matrix is discontinuously moved and is releasably sealed while in a stationary position. Both rotary and modular heat exchangers are described. Also described are methods for transferring heat between a hot and cold fluid using the discontinuous movement of matrices.

  1. Hierarchic modeling of heat exchanger thermal hydraulics

    International Nuclear Information System (INIS)

    Volume Averaging Technique (VAT) is employed in order to model the heat exchanger cross-flow as a porous media flow. As the averaging of the transport equations lead to a closure problem, separate relations are introduced to model interphase momentum and heat transfer between fluid flow and the solid structure. The hierarchic modeling is used to calculate the local drag coefficient Cd as a function of Reynolds number Reh. For that purpose a separate model of REV is built and DNS of flow through REV is performed. The local values of heat transfer coefficient h are obtained from available literature. The geometry of the simulation domain and boundary conditions follow the geometry of the experimental test section used at U.C.L.A. The calculated temperature fields reveal that the geometry with denser pin-fins arrangement (HX1) heats fluid flow faster. The temperature field in the HX2 exhibits the formation of thermal boundary layer between pin-fins, which has a significant role in overall thermal performance of the heat exchanger. Although presented discrepancies of the whole-section drag coefficient Cd are large, we believe that hierarchic modeling is an appropriate strategy for calculation of complex transport phenomena in heat exchanger geometries.(author)

  2. NUMERICAL SIMULATION OF VERTICAL GROUND HEAT EXCHANGERS FOR GROUND SOURCE HEAT PUMPS

    OpenAIRE

    Jalaluddin

    2011-01-01

    Abstract: This paper presents the numerical simulation of several types of vertical ground heat exchangers. The ground heat exchangers (GHEs) such as U-tube, double-tube and multi-tube were simulated using the commercial CFD software FLUENT. Water flows through the heat exchangers and exchanges the heat to the ground. The inlet and outlet water temperatures, flow rate, and heat exchange rate are presented. The heat exchange rates in discontinuous short-time period of operation ...

  3. Heat exchanger, specifically a steam generator heated with liquid sodium

    International Nuclear Information System (INIS)

    The invention concerns a heat exchanger, specifically a liquid sodium heated steam generator. This exchanger comprises a vertical long casing, a distributor for feeding the internal capacity of the casing with a first liquid coolant (liquid sodium), at least one bundle of tubes fitted inside the casing for the circulation of a second coolant (water), in indirect heat exchange relation with the first coolant, and facilities for maintaining in the casing a free given level of liquid topped by an inert gas atmosphere (argon). The upper ends of the tubes are fitted with thermal sleeves connecting them to the side wall of the casing for crossing it under the free liquid level and the distributor is placed in the casing above the bundle of tubes

  4. Heat exchanger and method for its production

    International Nuclear Information System (INIS)

    The patent refers to heat exchangers, preferably to steam generators for nuclear power stations, in which the parallel tubes are fixed to each other by welding to distancing elements. A method is described for the fabrication by a welding machine, so that the number of necessary tests can be reduced drastically. (P.K.)

  5. Heat exchanger and method for its production

    International Nuclear Information System (INIS)

    The patent refers to heat exchangers preferably steam generators for nuclear power stations with a number of parallel tubes arranged in curved planes. The fixing of the tubes to each other is accomplished by welding to distancing elements, e.g. fins of the adjacent tubes. This system eliminates the danger of fretting corrosion and vibration of the tubes. (P.K.)

  6. Exergo-ecological evaluation of heat exchanger

    Directory of Open Access Journals (Sweden)

    Stanek Wojciech

    2014-01-01

    Full Text Available Thermodynamic optimization of thermal devices requires information about the influence of operational and structural parameters on its behaviour. The interconnections among parameters can be estimated by tools such as CFD, experimental statistic of the deviceetc. Despite precise and comprehensive results obtained by CFD, the time of computations is relatively long. This disadvantage often cannot be accepted in case of optimization as well as online control of thermal devices. As opposed to CFD the neural network or regression is characterized by short computational time, but does not take into account any physical phenomena occurring in the considered process. The CFD model of heat exchanger was built using commercial package Fluent/Ansys. The empirical model of heat exchanger has been assessed by regression and neural networks based on the set of pseudo-measurements generated by the exact CFD model. In the paper, the usage of the developed empirical model of heat exchanger for the minimisation of TEC is presented. The optimisationconcerns operational parameters of heat exchanger. The TEC expresses the cumulative exergy consumption of non-renewable resources. The minimization of the TEC is based on the objective function formulated by Szargut. However, the authors extended the classical TEC by the introduction of the exergy bonus theory proposed by Valero. The TEC objective function fulfils the rules of life cycle analysis because it contains the investment expenditures (measured by the cumulative exergy consumption of non-renewable natural resources, the operation of devices and the final effects of decommissioning the installation.

  7. Heat exchanger for a contaminated fluid

    International Nuclear Information System (INIS)

    A heat exchanger, in particular for a contaminated fluid in the nuclear industry. The tubes forming the tube core are welded and crimped across the whole width of the tubular plate which defines the floating head together with the sealing cover, and said tubular plate is also welded and crimped to the calandria along the whole of its periphery. (author)

  8. Condensation and frost formation in heat exchangers

    International Nuclear Information System (INIS)

    The occurence of condensation and of frost formation are considered for air to heat exchangers with emphasis on how such occurrences would affect the performance of such heat exchangers when they are used in ventilating applications. The formulations which predict performance are developed for parallel, counter flow and cross flow with either formation or condensation, and for condensation the consequences for evaporation of condensate and of the effect of longitudinal conduction in the walls of the exchanger are also considered. For the prediction of the exchanger performance with frost formation there must be specified the growth of the frost layer with time and existing theories for this growth are examined, a new method of calculation of the growth is presented and this is shown to give results for the growth that are in accord with available experimental evidence. This new theory for the growth of a frost layer is used to predict the performance of a parallel flow exchanger under conditions in which frost formation occurs, by successively applying the steady state performance calculation for time increments over which the frost layer build-up is calculated for these time increments. The calculation of counter flow exchanger performance by this method, while feasible, is so time consuming that only the general aspects of the calculation are considered

  9. Heat exchange process, particularly to cool fission gases and heat exchanger to perform the method

    International Nuclear Information System (INIS)

    Heat exchangers developed for nuclear power plants could also be used for cooling fission gases from the hydropyrolysis of heavy hydrocarbons, particularly heat exchangers with an intermediate carrier filling of liquid metal (e.g. heavy metal alloy). As the heat exchanger surfaces have to be decoked from time to time when used for cooling fission gases, where high temperatures occur, it is proposed to change the level of the fill of the intermediate carrier fill by adding or removing intermediate carrier material. It is then possible to decoke without having to remove the cooling water. (UWI)

  10. Brayton heat exchange unit development program

    Science.gov (United States)

    Morse, C. J.; Richard, C. E.; Duncan, J. D.

    1971-01-01

    A Brayton Heat Exchanger Unit (BHXU), consisting of a recuperator, a heat sink heat exchanger and a gas ducting system, was designed, fabricated, and tested. The design was formulated to provide a high performance unit suitable for use in a long-life Brayton-cycle powerplant. A parametric analysis and design study was performed to establish the optimum component configurations to achieve low weight and size and high reliability, while meeting the requirements of high effectiveness and low pressure drop. Layout studies and detailed mechanical and structural design were performed to obtain a flight-type packaging arrangement. Evaluation testing was conducted from which it is estimated that near-design performance can be expected with the use of He-Xe as the working fluid.

  11. Intermediate heat exchanger project for Super Phenix

    International Nuclear Information System (INIS)

    The Super Phenix (1 200 MWe) intermediate heat exchangers are derived directly from those of Phenix (250 MWe) which has been in operation at Marcoule near Avignon (Gard - France) for the last two years. The active part structure (exchange tube bundle) is very similar for both reactors and design studies have proved that this concept, based on experience gained in Phenix plan construction, was able to achieve the required operating conditions. The characteristics related to reactor pool-type design are presented. Thermal, hydraulic and mechanical considerations are then presented. (Auth.)

  12. Preliminary SP-100/Stirling heat exchanger designs

    International Nuclear Information System (INIS)

    Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems

  13. Preliminary SP-100/Stirling heat exchanger designs

    International Nuclear Information System (INIS)

    Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor primary lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems

  14. Preliminary SP-100/Stirling heat exchanger designs

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, P.; Tower, L. [Sverdrup Technology, Inc., Brook Park, OH (United States). Lewis Research Center Group; Dawson, R. [Aerospace Design and Fabrication Inc., Brook Park, OH (United States); Blue, B.; Dunn, P. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center

    1994-09-01

    Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC`s are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems.

  15. Triple loop heat exchanger for an absorption refrigeration system

    Science.gov (United States)

    Reimann, Robert C. (Lafayette, NY)

    1984-01-01

    A triple loop heat exchanger for an absorption refrigeration system is disclosed. The triple loop heat exchanger comprises portions of a strong solution line for conducting relatively hot, strong solution from a generator to a solution heat exchanger of the absorption refrigeration system, conduit means for conducting relatively cool, weak solution from the solution heat exchanger to the generator, and a bypass system for conducting strong solution from the generator around the strong solution line and around the solution heat exchanger to an absorber of the refrigeration system when strong solution builds up in the generator to an undesirable level. The strong solution line and the conduit means are in heat exchange relationship with each other in the triple loop heat exchanger so that, during normal operation of the refrigeration system, heat is exchanged between the relatively hot, strong solution flowing through the strong solution line and the relatively cool, weak solution flowing through the conduit means. Also, the strong solution line and the bypass system are in heat exchange relationship in the triple loop heat exchanger so that if the normal flow path of relatively hot, strong solution flowing from the generator to an absorber is blocked, then this relatively, hot strong solution which will then be flowing through the bypass system in the triple loop heat exchanger, is brought into heat exchange relationship with any strong solution which may have solidified in the strong solution line in the triple loop heat exchanger to thereby aid in desolidifying any such solidified strong solution.

  16. Earth Air Heat Exchanger in Parallel Connection

    OpenAIRE

    ManojkumarDubey1 , Dr. J.L.Bhagoria2 , Dr. Atullanjewar

    2013-01-01

    The temperature of earth at a certain depth about 2 to 3m the temperature of ground remains nearly constant throughout the year. This constant temperature is called the undisturbed temperature of earth which remains higher than the outside temperature in winter and lower than the outside temperature in summer. When ambient air is drawn through buried pipes, the air is cooled in summer and heated in winter, before it is used for ventilation. The earth air heat exchanger can fulfil in both purp...

  17. Selection of materials for heat exchangers

    International Nuclear Information System (INIS)

    This paper provides a frame work for selecting heat exchangers materials especially those used in nuclear power plants. Typical examples of materials selection for heat exchanger tubing of nuclear power plants and condensers are presented. The paper brings out also, the importance of continued intensive R and D in materials in order to enhance the reliability and reduce cost by improving upon the existing materials by minor additions of alloying elements or new materials. The properties of Cr- Mo - alloys with minor additions of W, V, Nb and N are discussed in view of their use at elevated temperatures in the power industry. These alloys were found to provide considerable operation flexibility due to their low expansion coefficient and high thermal conductivity in comparison with the austenitic stainless steels. Also, the Ni base alloy Inconel 617. Could be selected for his excellent combination of creep and hot corrosion resistance up to a temperature of a 50 degree C. 2 figs., 7 tabs

  18. Tubular heat exchanger, for nuclear installations

    International Nuclear Information System (INIS)

    The description is given of a heat exchanger comprising an elongated heat exchanger module suitable for group mounting with other similar modules. The module includes a long casing having a hexagonal cross section configuration to make it easy to group together a set of modules in an appreciably continuous set. A set of thermally conducting tubes is arranged in the casing and extends through its entire length. An intake collector is fitted to one end of the casing and communicates with one end of the tubes and an outlet collector is fitted to the other end of the casing and communicates with the other end of the tubes, a fluid passage being made inside the casing for the flow of primary fluid through it around the thermally conducting tubes. The intake and outlet collectors are each fitted for their respective coupling to an intake manifold and an outlet manifold for the flow of a primary fluid through the tubes in the casing

  19. Heat Exchanger for Motor Vehicle Cooling System

    OpenAIRE

    Thuliez, Jean-Luc; Chevroulet, Tristan; Stoll, Daniel

    1997-01-01

    Heat exchanger for a motor vehicle cooling system including a sleeve-like meter hermetically mounted on, and surrounding, a hollow tubular chassis meter of the vehicle. The sleeve is provided with inlets and outlets communicating with the space between the sleeve and the chassis meter and vehicle coolant flows through the inlet and outlet. Air, flowing over the outside surface of the sleeve and the inside surface of the chassis meter, cools the vehicle coolant. SMH - MCC Smart, car concepts (...

  20. Comparative studies on micro heat exchanger optimisation.

    OpenAIRE

    Okabe, T.; Foli, K; Olhofer, M; Jin, Y; Sendhoff, B

    2003-01-01

    Although many methods for dealing with multi-objective optimisation (MOO) problems are available as stated in K. Deb (2001) and successful applications have been reported on C.A. Coello et al. (2001), the comparison between MOO methods applied to real-world problem was rarely carried out. This paper reports the comparison between MOO methods applied to a real-world problem, namely, the optimization of a micro heat exchanger (?HEX). Two MOO methods, dynamically weighted aggregation (DWA) propo...

  1. Heat exchangers and methods of construction thereof

    International Nuclear Information System (INIS)

    A heat exchanger is described comprising a shell having first inlet means and first outlet means for the flow of a first fluid therethrough, a plurality of tubes within the shell to provide a path for flow of a second fluid in heat exchange relation to the first fluid, second inlet means and second outlet means for flow of the second fluid to and from the tubes respectively, a tubular member concentric with at least a portion of the length of one of the tubes to define a space between the tube and the tubular member, at least one radially outwardly projecting portion on the tubular member, and a plurality of tube support means spaced apart and disposed generally perpendicular to the tube axes, wherein the tubular member is fixedly attached at one end to one of the tube support means and at the other end to an adjacent one of the tube support means, the space between the tube and the tubular member is closed to flow of both the first fluid and the second fluid, and the radially outwardly projecting portion on the tubular member extends longitudinally to allow flexing of the tubular member and expanding thereof radially outwardly during construction of the heat exchanger so as to allow insertion of the tube into the tubular member, the radially outwardly projecting portion defining a gap which contributes to the space between the tube and the tubular member. 6 figs

  2. Inner inspection device for heat exchanger

    International Nuclear Information System (INIS)

    The device of the present invention is most suitable to the inner inspection for an intermediate heat exchanger of a HTGR type reactor. That is, the device comprises (1) a device for grinding/polishing the surface of a portion to be inspected, (2) a device for etching the polished surface, (3) a device for directly observing the etched surface or sampling a replica, (4) a conveyor, (5) an image observation device for analyzing/calculating the extent of the creep deformation based on the information from the metal tissues obtained by the device in (3) and (6) a control device for remote controlling the inner device. With such a constitution, the inner inspection device is sent to the heat exchanger by the device (4). The portion to be inspected in the heat exchanger is ground/polished into a mirror surface by the device (2). Then, the mirror surface metal tissues are observed by the device (3). Information of the metal tissues obtained as the result is sent to the device (5), in which the extent of damages can be observed and evaluated. In the method of the present invention, the inspection accuracy is improved compared with an ultrasonic defect scoping method and an eddy current defect scoping method. (I.S.)

  3. Fouling of a plate heat exchanger by cheese whey solutions

    OpenAIRE

    Corcoran, Brian

    1997-01-01

    A plate heat exchanger rig was developed at Dublin City University to study fouling of plate heat exchangers using cheese whey solutions. The rig consisted of an Alfa-Laval plate heat exchanger, 316 stainless steel pipework, pressure and temperature measurement and was temperature controlled with all information logged via an Anville data acquisition system. Cheese whey solutions of various concentration were passed through the plate heat exchanger for periods of up to four hours. The eff...

  4. Performance Investigation of Plate Type Heat Exchanger (A Case Study

    Directory of Open Access Journals (Sweden)

    Simarpreet Singh

    2014-04-01

    Full Text Available Heat exchanger is a thermodynamic system which is most commonly used in the process industry for exchanging heat energy between the fluids. flowing in the same or opposite direction. It is desired that effectiveness of heat exchanger should remain as large as possible. Heat exchanger's performance may be improved by the addition of fins or corrugations. These investigations include design of plate type heat exchanger, heat transfer enhancement, flow phenomenon and cleanliness factor. In process plants, this type of heat exchange is generally used for recovering heat content of exhaust steam. However, with the flow of fluid for a long period, fouling occurs on the plate surface. Therefore, it is required to investigate the effect of fouling, wherever the heat exchanger is installed. An extensive experimental investigation has been carried out under clean and dirty condition of the said plate type heat exchanger. Heat transfer and flow data were collected in experiment. From collected data heat transfer rate, overall heat transfer coefficient, fouling factor and cleanliness factor were evaluated. Based upon the cleanliness factor data, next date of cleanliness for plate type heat exchanger was predicted. It is felt that the outcome of the present research work may be quite useful for efficient operation of plate type heat exchanger installed in Process plants.

  5. 40 CFR 63.104 - Heat exchange system requirements.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Heat exchange system requirements. 63... § 63.104 Heat exchange system requirements. (a) Unless one or more of the conditions specified in... subpart shall monitor each heat exchange system used to cool process equipment in a chemical...

  6. 40 CFR 63.1328 - Heat exchange systems provisions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Heat exchange systems provisions. 63... Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins § 63.1328 Heat exchange... of this subpart. (h) The compliance date for heat exchange systems subject to the provisions of...

  7. 40 CFR 63.1409 - Heat exchange system provisions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Heat exchange system provisions. 63... each heat exchange system used to cool process equipment in an affected source, according to the... shall comply with the requirements in paragraph (d) of this section. (1) The heat exchange system...

  8. 40 CFR 63.654 - Heat exchange systems.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Heat exchange systems. 63.654 Section... Emission Standards for Hazardous Air Pollutants From Petroleum Refineries § 63.654 Heat exchange systems...) of this section, the owner or operator of a heat exchange system that meets the criteria in §...

  9. 40 CFR 63.1435 - Heat exchanger provisions.

    Science.gov (United States)

    2010-07-01

    ...) When the HON heat exchange system requirements in § 63.104 refer to Table 4 of 40 CFR part 63, subpart... for heat exchange systems, with the exceptions noted in paragraphs (b) through (e) of this section. (b...)” shall apply for the purposes of this subpart. (c) When the HON heat exchange system requirements in §...

  10. Graphite Foam Heat Exchangers for Thermal Management

    Energy Technology Data Exchange (ETDEWEB)

    Klett, J.W.

    2004-06-07

    Improved thermal management is needed to increase the power density of electronic and more effectively cool electronic enclosures that are envisioned in future aircraft, spacecraft and surface ships. Typically, heat exchanger cores must increase in size to more effectively dissipate increased heat loads, this would be impossible in many cases, thus improved heat exchanger cores will be required. In this Phase I investigation, MRi aimed to demonstrate improved thermal management using graphite foam (Gr-foam) core heat exchangers. The proposed design was to combine Gr-foams from POCO with MRi's innovative low temperature, active metal joining process (S-Bond{trademark}) to bond Gr-foam to aluminum, copper and aluminum/SiC composite faceplates. The results were very favorable, so a Phase II SBIR with the MDA was initiated. This had primarily 5 tasks: (1) bonding, (2) thermal modeling, (3) cooling chip scale packages, (4) evaporative cooling techniques and (5) IGBT cold plate development. The bonding tests showed that the ''reflow'' technique with S-Bond{reg_sign}-220 resulted in the best and most consistent bond. Then, thermal modeling was used to design different chip scale packages and IGBT cold plates. These designs were used to fabricate many finned graphite foam heat sinks specifically for two standard type IC packages, the 423 and 478 pin chips. These results demonstrated several advantages with the foam. First, the heat sinks with the foam were lighter than the copper/aluminum sinks used as standards. The sinks for the 423 design made from foam were not as good as the standard sinks. However, the sinks made from foam for the 478 pin chips were better than the standard heat sinks used today. However, this improvement was marginal (in the 10-20% better regime). However, another important note was that the epoxy bonding technique resulted in heat sinks with similar results as that with the S-bond{reg_sign}, slightly worse than the S-bond{reg_sign}, but still better than the standard heat sinks. Next, work with evaporative cooling techniques, such as heat pipes, demonstrated some unique behavior with the foam that is not seen with standard wick materials. This was that as the thickness of the foam increased, the performance got better, where with standard wick materials, as the thickness increases, the performance decreases. This is yet to be completely explained. Last, the designs from the thermal model were used to fabricate a series of cold plates with the graphite foam and compare them to similar designs using high performance folded fin aluminum sinks (considered standard in the industry). It was shown that by corrugating the foam parallel to fluid flow, the pressure drop can be reduced significantly while maintaining the same heat transfer as that in the folded fin heat sink. In fact, the results show that the graphite foam heat sink can utilized 5% the pumping power as that required with the folded fin aluminum heat sink, yet remove the same amount of heat.

  11. Comparative analysis of compact heat exchangers for application as the intermediate heat exchanger for advanced nuclear reactors

    International Nuclear Information System (INIS)

    Highlights: • Compact heat exchanger designs evaluated for advanced nuclear reactor applications. • Wavy channel PCHE compared with offset strip-fin heat exchanger (OSFHE). • 15° pitch angle wavy channel PCHE offers optimum performance characteristics. • OSFHE exhibits higher pressure drop and lower compactness than other options. • Comparison technique applicable for evaluating candidate heat exchangers designs. - Abstract: A comparative evaluation of alternative compact heat exchanger designs for use as the intermediate heat exchanger in advanced nuclear reactor systems is presented in this article. Candidate heat exchangers investigated included the Printed circuit heat exchanger (PCHE) and offset strip-fin heat exchanger (OSFHE). Both these heat exchangers offer high surface area to volume ratio (a measure of compactness [m2/m3]), high thermal effectiveness, and overall low pressure drop. Helium–helium heat exchanger designs for different heat exchanger types were developed for a 600 MW thermal advanced nuclear reactor. The wavy channel PCHE with a 15° pitch angle was found to offer optimum combination of heat transfer coefficient, compactness and pressure drop as compared to other alternatives. The principles of the comparative analysis presented here will be useful for heat exchanger evaluations in other applications as well

  12. Numerical simulation of the thermal behavior of heat transfer equipment operated at low temperature

    International Nuclear Information System (INIS)

    The paper presents a method for calculating the non-steady heat transfer in a shell and tube heat exchanger. The characteristic equations were solved with a Finite Element Method. As the geometry is cylindrical and axial symmetry was assumed, the equations were solved in a two dimensional geometry. The interpolation functions are linear and the Galerkin method was applied. The process occurred without phase change. For the solving of the algebraic equations associated with the differential equations, we used the method of steepest descendent (gradient method). As results, we present the temperature profile for the tube and shell gas. (author)

  13. Microchannel Heat Exchangers with Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y.; Ohadi, M.M.; Radermacher, R.

    2001-09-15

    The objective of the present study was to determine the performance of CO{sub 2} microchannel evaporators and gas coolers in operational conditions representing those of residential heat pumps. A set of breadboard prototype microchannel evaporators and gas coolers was developed and tested. The refrigerant in the heat exchangers followed a counter cross-flow path with respect to the airflow direction. The test conditions corresponded to the typical operating conditions of residential heat pumps. In addition, a second set of commercial microchannel evaporators and gas coolers was tested for a less comprehensive range of operating conditions. The test results were reduced and a comprehensive data analysis, including comparison with the previous studies in this field, was performed. Capacity and pressure drop of the evaporator and gas cooler for the range of parameters studied were analyzed and are documented in this report. A gas cooler performance prediction model based on non-dimensional parameters was also developed and results are discussed as well. In addition, in the present study, experiments were conducted to evaluate capacities and pressure drops for sub-critical CO{sub 2} flow boiling and transcritical CO{sub 2} gas cooling in microchannel heat exchangers. An extensive review of the literature failed to indicate any previous systematic study in this area, suggesting a lack of fundamental understanding of the phenomena and a lack of comprehensive data that would quantify the performance potential of CO{sub 2} microchannel heat exchangers for the application at hand. All experimental tests were successfully conducted with an energy balance within {+-}3%. The only exceptions to this were experiments at very low saturation temperatures (-23 C), where energy balances were as high as 10%. In the case of evaporators, it was found that a lower saturation temperature (especially when moisture condensation occurs) improves the overall heat transfer coefficient significantly. However, under such conditions, air side pressure drop also increases when moisture condensation occurs. An increase in airflow rate also increases the overall heat transfer coefficient. Air side pressure drop mainly depends on airflow rate. For the gas cooler, a significant portion of the heat transfer occurred in the first heat exchanger module on the refrigerant inlet side. The temperature and pressure of CO{sub 2} significantly affect the heat transfer and fluid flow characteristics due to some important properties (such as specific heat, density, and viscosity). In the transcritical region, performance of CO{sub 2} strongly depends on the operating temperature and pressure. Semi-empirical models were developed for predictions of CO{sub 2} evaporator and gas cooler system capacities. The evaporator model introduced two new factors to account for the effects of air-side moisture condensate and refrigerant outlet superheat. The model agreed with the experimental results within {+-}13%. The gas cooler model, based on non-dimensional parameters, successfully predicted the experimental results within {+-}20%. Recommendations for future work on this project include redesigning headers and/or introducing flow mixers to avoid flow mal-distribution problems, devising new defrosting techniques, and improving numerical models. These recommendations are described in more detail at the end of this report.

  14. Characteristics of heat flow in recuperative heat exchangers

    Directory of Open Access Journals (Sweden)

    Lalovi? Milisav

    2005-01-01

    Full Text Available A simplified model of heat flow in cross-flow tube recuperative heat exchangers (recuperators was presented in this paper. One of the purposes of this investigation was to analyze changes in the values of some parameters of heat transfer in recuperators during combustion air preheating. The logarithmic mean temperature (Atm and overall heat transfer coefficient (U, are two basic parameters of heat flow, while the total heated area surface (A is assumed to be constant. The results, presented as graphs and in the form of mathematical expressions, were obtained by analytical methods and using experimental data. The conditions of gaseous fuel combustions were defined by the heat value of gaseous fuel Qd = 9263.894 J.m-3, excess air ratio ?= 1.10, content of oxygen in combustion air ?(O2 = 26%Vol, the preheating temperature of combustion air (cold fluid outlet temperature tco = 100-500°C, the inlet temperature of combustion products (hot fluid inlet temperature thi = 600-1100°C.

  15. Investigation Status of Heat Exchange while Boiling Hydrocarbon Fuel

    Directory of Open Access Journals (Sweden)

    D. S. Obukhov

    2014-06-01

    Full Text Available The paper contains analysis of heat exchange investigations while boiling hydrocarbon fuel. The obtained data are within the limits of the S.S. Kutateladze dependence proposed in 1939. Heat exchange at non-stationary heat release has not been investigated. The data for hydrocarbon fuel with respect to critical density of heat flow are not available even for stationary conditions.

  16. Technology Solutions Case Study: Foundation Heat Exchanger, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-03-01

    The foundation heat exchanger, developed by Oak Ridge National Laboratory, is a new concept for a cost-effective horizontal ground heat exchanger that can be connected to water-to-water or water-to-air heat pump systems for space conditioning as well as domestic water heating.

  17. Heat exchange apparatus for a reactor

    International Nuclear Information System (INIS)

    A heat exchange apparatus for transferring heat from a reactor gas coolant to a secondary fluid medium is described. The heat exchange apparatus comprises an elongated vertically extending hole in a concrete shield. Supported within the hole in spaced relation to the wall thereof is an elongated vertical extending tubular shroud which shroud has a gas entry at its lower end and a gas exit at its upper end. Means are provided for dividing the annular space between the shroud 16 and the wall of the hole into an upper and a lower region. Disposed in the shield is an inlet for reactor coolant which communicates with the lower region and is positioned vertically so as to be spaced above the gas entry to the shroud to thereby suppress natural convection during nonoperating standby conditions of the apparatus. An outlet for reactor coolant, which is disposed in the shield, communicates with the upper region. A plurality of vertically extending, spaced apart bayonet tube assemblies are supported within the shroud and means are provided for passing secondary fluid through these tube assemblies. A circulator is provided for causing the reactor coolant to flow in through the inlet, downward in the annular space, into the shroud through the gas entry, upward through the shroud and out through the outlet during emergency conditions of the reactor

  18. Design of a liquid metals heat exchanger

    International Nuclear Information System (INIS)

    The method that has been used in this design is that of the summation of the partial resistances to the heat transference, permitting to obtain the value of the total coefficient of heat transfer which will be equal to the reciprocal of the summation of all the resistances. The obtained exchanger is of tubes and rod type shield with the primary sodium flowing through the tubes and the secondary sodium flowing in counter-current through the shield. The shield has a nominal diameter of 6 inches and the bundle of tubes is formed by 31 tubes with a nominal diameter of 1/2 inch. The shield as well as the tubes are of stainless steel. The total heat transfer area is of 7.299 square meters, and the effective length of heat transfer is of 3.519 meters. After sizing the interchanger it was proceeded to simulate its functioning through a computer program in which the effective length of heat transfer was divided in 150 points in such a way that according to the integration of the distinct parameters along these points a comparison can finally be made between the design values and those of the simulation, which show a concordance. (author)

  19. Performance of heat pumps with direct expansion in vertical ground heat exchangers in heating mode

    International Nuclear Information System (INIS)

    Highlights: • The work focuses on direct expansion ground source heat pumps in heating mode. • The evaporating process of the refrigerant fluid into boreholes is analyzed. • A method to design the direct expansion borehole heat exchangers is presented. • Direct expansion and the common secondary loop heat pumps are compared. • The comparison is carried out in terms of both borehole length and performance. - Abstract: Ground source heat pump systems represent an interesting example of renewable energy technology for heating and cooling of buildings. The connection with the ground is usually done by means of a closed loop where a heat-carrier fluid (pure water or a solution of antifreeze and water) flows and, in heating mode, moves heat from ground to refrigerant fluid of heat pump. A new solution is the direct expansion heat pump. In this case, the heat-carrier fluid inside the ground loop is the same refrigerant fluid of heat pump. This paper focuses on the energy performance of direct expansion ground source heat pump with borehole heat exchangers in heating mode, looking at residential building installations. For this purpose, the evaporating process of the refrigerant fluid inside vertical tubes is investigated in order to analyze the influence of the convective heat transfer coefficient on the global heat transfer with the surrounding ground. Then, an analytical model reported in literature for the design of common borehole heat exchangers has been modified for direct expansion systems. Finally, the direct expansion and common ground source heat pumps have been compared in terms of both total borehole length and thermal performance. Results indicate that the direct expansion system has higher energy performance and requires lower total borehole length compared to the common system. However, when the two systems are compared with the same mean fluid evaporating temperature, the overall length of the ground heat exchanger of the direct expansion heat pump is greater than that of the common system

  20. Expanded microchannel heat exchanger: design, fabrication and preliminary experimental test

    CERN Document Server

    Denkenberger, David C; Pearce, Joshua M; Zhai, John; 10.1177/0957650912442781

    2012-01-01

    This paper first reviews non-traditional heat exchanger geometry, laser welding, practical issues with microchannel heat exchangers, and high effectiveness heat exchangers. Existing microchannel heat exchangers have low material costs, but high manufacturing costs. This paper presents a new expanded microchannel heat exchanger design and accompanying continuous manufacturing technique for potential low-cost production. Polymer heat exchangers have the potential for high effectiveness. The paper discusses one possible joining method - a new type of laser welding named "forward conduction welding," used to fabricate the prototype. The expanded heat exchanger has the potential to have counter-flow, cross-flow, or parallel-flow configurations, be used for all types of fluids, and be made of polymers, metals, or polymer-ceramic precursors. The cost and ineffectiveness reduction may be an order of magnitude or more, saving a large fraction of primary energy. The measured effectiveness of the prototype with 28 micro...

  1. Steam generator with duplex heat exchange tubes

    International Nuclear Information System (INIS)

    The invention claims a design of a steam generator for fast reactors. The advantage of the design is that it does not require additional expansion tanks for the steam generator and that the steam generator may be filled with indication liquid, e.g., sodium, after assembly work has been completed at the power plant. Another advantage is that in a vertical steam generator with duplex heat exchange tubes the configuration facilitates the detection of a failure of the walls of the duplex tubes. (J.P.)

  2. PENGARUH TEBAL ISOLASI TERMAL TERHADAP EFEKTIVITAS PLATE HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    Ekadewi Anggraini Handoyo

    2000-01-01

    Full Text Available In a heat exchanger, there is heat transferred either from the surrounding or to the surrounding, which is not expected. A thermal insulator is used to reduce this heat transfer. The effectiveness of a heat exchanger will increase if the heat loss to surrounding can be reduced. Theoretically, the thicker the insulator the smaller the heat loss in a plate heat exchanger. A research is carried on to study the effect of an insulator thickness on heat exchanger effectiveness. The insulators used are glasswool and rockwool. It turns out that the effectiveness is increasing until a maximum point, and then decreasing when the thickness of the insulator is increasing. Abstract in Bahasa Indonesia : Dalam suatu heat exchanger selalu terjadi perpindahan panas ke atau dari lingkungan yang tidak diharapkan. Untuk mengurangi perpindahan panas ini digunakan isolator termal. Efektivitas heat exchanger akan meningkat jika panas yang hilang ke atau dari lingkungan dapat dikurangi. Secara teoritis untuk heat exchanger berbentuk kotak semakin tebal isolator termal yang digunakan semakin kecil panas mengalir ke atau dari lingkungan. Dalam penelitian ini dicari pengaruh ketebalan isolator termal terhadap efektivitas suatu plate heat exchanger. Percobaan dilakukan untuk 2 jenis isolator, yaitu glasswool dan rockwool. Hasil yang didapat adalah efektivitas akan meningkat sampai harga tertentu dan kemudian akan berkurang dengan penambahan ketebalan isolator termal. Kata kunci: isolator termal, efektivitas, plate heat exchanger.

  3. Heat Exchanger Anchors for Thermo-active Tunnels

    OpenAIRE

    Mimouni, Thomas; Dupray, Fabrice; Minon, Sophie; Laloui, Lyesse

    2013-01-01

    Shallow geothermal power represents an important energy resource for the heating and cooling of the buildings. Due to relatively low temperature levels encountered at shallow depths in the soil, between 10°C and 20°C, heat pumps are required to process the extracted heat, forming the so called ground source heat pump system. Different types of heat exchangers with the ground were developed in order to optimize the heat exchanges, from simple geothermal loops grouted in boreholes reaching dept...

  4. Intermediate heat exchanger project for Super Phenix

    International Nuclear Information System (INIS)

    The Super Phenix (1200 MWe) intermediate heat exchangers are derived directly from those of Phenix (250 MWe). The intermediate exchangers are housed in the reactor vessel annulus: as this annulus must be of the smallest volume possible, these IHX are required to work at a high specific rating. The exchange surface is calculated for nominal conditions. A range is then defined, consistent with the above requirements and throughout which the ratio between bundle thickness and bundle length remains acceptable. Experimental technics and calculations were used to determine the number of tube constraint systems required to keep the vibration amplitude within permissible limits. From a knowledge of this number, the pressure drop produced by the primary flow can be calculated. The bundle geometry is determined together with the design of the corresponding tube plates and the way in which these plates should be joined to the body of the IHX. The experience (technical and financial) acquired in the construction of Phenix is then used to optimize the design of the Super Phenix project. An approximate definition of the structure of the IHX is obtained by assuming a simplified load distribution in the calculations. More sophisticated calculations (e.g. finite element method) are then used to determine the behaviour of the different points of the IHX, under nominal and transient conditions

  5. Finned heat exchanger. Ib. General and basic aspects

    International Nuclear Information System (INIS)

    This paper is a review of the main literature studies about the finned heat exchanger modelling and simulation. Finned heat exchangers are used in cryogenic industry, nuclear industry, food industry, medicine, etc.. The aspects concerning the air circulation through the heat exchanger component tubes are studied, as well as those involved in the thermal transfer from technological fluid to wall or from fin to air. A particular attention is devoted to the physical and mathematical complete models of finned heat exchangers, as well as to the criterial relationship for the calculation of the partial heat transfer to air (?2), fin efficiency (?a) and friction coefficient (f). Details are also given about the influence of the thermal contact resistance on the finned heat exchanger performance. This study is a useful tool for a correct technological sizing of this type of heat exchangers. (authors)

  6. Simulation Studies on A Cross Flow Plate Fin Heat Exchanger

    Directory of Open Access Journals (Sweden)

    M. Thirumarimurugan

    2008-01-01

    Full Text Available Compact heat exchangers which were initially developed for the aerospace industries in the1940s have been considerably improved in the past few years. The main reasons for the goodperformance of compact heat exchangers are their special design which includes turbulent which inturn use high heat transfer coefficient and resists fouling, and maximum temperature driving forcebetween the hot and cold fluids. Numerous types use special enhancement techniques to achieve therequired heat transfer in smaller plot areas and, in many cases, less initial investment. One such type ofcompact heat exchanger is the Plate-fin heat exchanger. The complexity of compact heat exchangerdesign equations results from the exchangers unique ability to transfer heat between multiple processstreams and a wide array of possible flow configurations. This paper presents the performanceevaluation of cross flow plate fin heat exchanger with several different Gas-Liquid systems.Experimental results such as exchanger effectiveness, overall heat transfer coefficients were calculatedfor the flow systems of Cross flow Heat Exchangers. A steady state model for the outlet temperature ofboth the cold and hot fluid and overall heat transfer coefficient of a plate-fin cross flow heat exchangerwas developed and simulated using MATLAB, which was verified with the experiments conducted.

  7. New waste heat district heating system with combined heat and power based on absorption heat exchange cycle in China

    International Nuclear Information System (INIS)

    A new waste heat district heating system with combined heat and power based on absorption heat exchange cycle (DHAC) was developed to increase the heating capacity of combined heat and power (CHP) through waste heat recovery, and enhance heat transmission capacity of the existing primary side district heating network through decreasing return water temperature by new type absorption heat exchanger (AHE). The DHAC system and a conventional district heating system based on CHP (CDH) were analyzed in terms of both thermodynamics and economics. Compared to CDH, the DHAC increased heating capacity by 31% and increased heat transmission capacity of the existing primary side district heating network by 75%. The results showed that the exergetic efficiency of DHAC was 10.41% higher and the product exergy monetary cost was 36.6¥/GJ less than a CHD. DHAC is an effective way to increase thermal utilization factor of CHP, and to reduce district heating cost. - Highlights: ? Absorption heat pumps are used to recover waste heat in CHP. ? Absorption heat exchanger can reduce exergy loss in the heat transfer process. ? New waste heat heating system (DHAC) can increase heating capacity of CHP by 31%. ? DHAC can enhance heat transmission capacity of the primary pipe network by 75%. ? DHAC system has the higher exergetic efficiency and the better economic benefit.

  8. Control Dewar Subcooler Heat Exchanger Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Rucinski, R.; /Fermilab

    1993-10-04

    The calculations done to size the control dewar subcooler were done to obtain a sufficient subcooler size based on some conservative assumptions. The final subcooler design proposed in the design report will work even better because (1) It has more tubing length, and (2) will have already subcooled liquid at the inlet due to the transfer line design. The subcooler design described in the 'Design Report of the 2 Tesla Superconducting Solenoid for the Fermilab D0 Detector Upgrade' is the final design proposed. A short description of this design follows. The subcooler is constructed of 0.50-inch OD copper tubing with 1.0-inch diameter fins. It has ten and one half spirals at a 11.375-inch centerline diameter to provide 31 feet of tubing length. The liquid helium supply for the solenoid flows through the subcooler and then is expanded through a J-T valve. The subcooler spirals are immersed in the return two phase helium process stream. The return stream is directed over the finned tubing by an annulus created by a 10-inch pipe inside a 12-inch pipe. The transfer line from the refrigerator to the control dewar is constructed such that the liquid helium supply tube is in the refrigerator return stream, thereby subcooling the liquid up to the point where the u-tubes connect the transfer line to the control dewar. The subcooler within the control dewar will remove the heat picked up in the helium supply u-tube/bayonets. The attached subcooler/heat exchanger calculations were done neglecting any subcooling in the transfer line. All heat picked up in the transfer line from the refrigerator storage dewar to the control dewar is absorbed by the supply stream. The subcooler was sized such that the two phase supply fluid is subcooled at 1.7 atm pressure and when expanded through a JT valve to 1.45 atm pressure it is at a saturated liquid state. The calculations apply during steady state operation and at a flow rate of 16 g/s. The analysis of the heat exchanger was broken into two parts relating to the heat transfer mode taking place. The first part is considered the condensing part in which the helium supply stream is changed from two phase fluid to one phase liquid. The second part is the subcooling part where the liquid temperature is lowered, i.e.. subcooled. A summary of the calculations and results appears on the next page. The raw calculations follow the summary.

  9. Numerical Analysis of Tube-Fin Heat Exchanger using Fluent

    OpenAIRE

    M. V. Ghori; R. K. Kirar

    2012-01-01

    Three-dimensional CFD simulations are carried out to investigate heat transfer and fluid flow characteristics of two-row plain Tube and Fin heat exchanger using FLUENT software. Heat transfer and pressure drop characteristics of the heat exchanger are investigated for Reynolds numbers ranging from 330 to 7000. Model geometry is created and meshed by using GAMBIT software. Fluid flow and heat transfer are simulated and results compared using both laminar and turbulent flow models k-, and SST k...

  10. CFD Based Evaluation Of Effectiveness Of Counter Flow Heat Exchanger

    OpenAIRE

    Gurpreet Kour

    2014-01-01

    Engineers are continually being asked to improve effectiveness of heat transfer equipments. These requests may arise as a result of the need to increase profitability or accommodate capital limitations. Processes which use heat transfer equipment i.e. heat exchanger must frequently be improved for these reasons. Artifical roughness is important technique for enhancing the effectiveness of heat exchanger. In this work effectiveness of smooth as well as roughened tube in heat ex...

  11. Investigation of Brazed Plate Heat Exchangers With Variable Chevron Angles

    OpenAIRE

    S. Muthuraman

    2013-01-01

    - Experiments to measure the condensation heat transfer coefficient and the pressure drop in brazed plate heat exchangers (BPHEs) were performed with the refrigerants R410A and R22. Brazed plate heat exchangers with different chevron angles of 45°, 35°, and 20° were used. Varying the mass flux, the condensation temperature, and the vapor quality of the refrigerant, we measured the condensation heat transfer coefficient and the pressure drops. Both the heat transfer coefficient and the pressur...

  12. HEAT TRANSFER COEFFICIENT AND FRICTION FACTOR CHARACTERISTICS OF A GRAVITY ASSISTED BAFFLED SHELL AND HEAT-PIPE HEAT EXCHANGER

    OpenAIRE

    P. Raveendiran; SIVARAMAN B

    2015-01-01

    The heat transfer coefficients and friction factors of a baffled shell and heat pipe heat exchanger with various inclination angles were determined experimentally; using methanol as working fluid and water as heat transport fluid were reported. Heat pipe heat exchanger reported in this investigation have inclination angles varied between 15o and 60o for different mass flow rates and temperature at the shell side of the heat exchanger. All the required parameters like outlet temperature of bot...

  13. Heat exchanger for fuel cell power plant reformer

    Science.gov (United States)

    Misage, Robert (Manchester, CT); Scheffler, Glenn W. (Tolland, CT); Setzer, Herbert J. (Ellington, CT); Margiott, Paul R. (Manchester, CT); Parenti, Jr., Edmund K. (Manchester, CT)

    1988-01-01

    A heat exchanger uses the heat from processed fuel gas from a reformer for a fuel cell to superheat steam, to preheat raw fuel prior to entering the reformer and to heat a water-steam coolant mixture from the fuel cells. The processed fuel gas temperature is thus lowered to a level useful in the fuel cell reaction. The four temperature adjustments are accomplished in a single heat exchanger with only three heat transfer cores. The heat exchanger is preheated by circulating coolant and purge steam from the power section during startup of the latter.

  14. Finned heat exchangers. Ia. General and basic aspects

    International Nuclear Information System (INIS)

    This paper is a review of the main literature studies about the finned heat exchanger modelling and simulation. Finned heat exchangers are used in cryogenic industry, nuclear industry, food industry, medicine, etc. The aspects concerning the air circulation through the heat exchanger component tubes are studied, as well as those involved in the thermal transfer from technological fluid to wall or from fin to air. A particular attention is devoted to the physical and mathematical complete models of finned heat exchangers, as well as to the criterial relationship for the calculation of the partial thermal transfer to air, ?2, fin efficiency, ?a and friction coefficient, f. Details are also given about the influence of the thermal contact resistance on the finned heat exchanger performance. This study is a useful tool for a correct technological sizing of this heat exchanger type. (authors)

  15. Heat exchangers and the performance of heat pumps - Analysis of a heat pump database

    International Nuclear Information System (INIS)

    Heat pumping is a highly energy-efficient technology that could help reduce energy and environmental problems. The efficiency of a heat pump greatly depends on the individual and integral performance of the components inside. In this study, heat pump performance is investigated with a special focus on heat exchangers. Experimental data obtained from comprehensive heat pump measurements performed at the Austrian Institute of Technology (AIT) were analyzed with the help of thermodynamic models developed for this purpose. The analysis shows that the performance of heat exchangers varies widely resulting in substantial COP differences among the heat pumps. The models and methodology developed in this study are found capable of extracting useful information from measurement data quickly and accurately and could be useful for the industry. - Research highlights: ? A heat pump database has been analyzed focussing on the influences of heat exchangers on COP. ? It was shown that an empirical equation could excellently correlate experimental COP data with relevant parameters. ? It was found that heat exchanger design alone caused 15-20% difference in COP.

  16. Two-phase Flow Distribution in Heat Exchanger Manifolds

    OpenAIRE

    Vist, Sivert

    2004-01-01

    The current study has investigated two-phase refrigerant flow distribution in heat exchange manifolds. Experimental data have been acquired in a heat exchanger test rig specially made for measurement of mass flow rate and gas and liquid distribution in the manifolds of compact heat exchangers. Twelve different manifold designs were used in the experiments, and CO2 and HFC-134a were used as refrigerants.

  17. Heat exchanger and water tank arrangement for passive cooling system

    Science.gov (United States)

    Gillett, James E. (Greensburg, PA); Johnson, F. Thomas (Baldwin Boro, PA); Orr, Richard S. (Pittsburgh, PA); Schulz, Terry L. (Murrysville Boro, PA)

    1993-01-01

    A water storage tank in the coolant water loop of a nuclear reactor contains a tubular heat exchanger. The heat exchanger has tubesheets mounted to the tank connections so that the tubesheets and tubes may be readily inspected and repaired. Preferably, the tubes extend from the tubesheets on a square pitch and then on a rectangular pitch therebetween. Also, the heat exchanger is supported by a frame so that the tank wall is not required to support all of its weight.

  18. High temperature heat exchanger studies for applications to gas turbines

    Science.gov (United States)

    Min, June Kee; Jeong, Ji Hwan; Ha, Man Yeong; Kim, Kui Soon

    2009-12-01

    Growing demand for environmentally friendly aero gas-turbine engines with lower emissions and improved specific fuel consumption can be met by incorporating heat exchangers into gas turbines. Relevant researches in such areas as the design of a heat exchanger matrix, materials selection, manufacturing technology, and optimization by a variety of researchers have been reviewed in this paper. Based on results reported in previous studies, potential heat exchanger designs for an aero gas turbine recuperator, intercooler, and cooling-air cooler are suggested.

  19. Fluidelastic instability of heat exchanger tube bundles

    International Nuclear Information System (INIS)

    This paper reports that fluidelastic instability is the most important vibration excitation mechanism for heat exchanger tube bundles subjected to cross-flow. Most of the available data on this topic have been reviewed from the perspective of the designer. Uniform definitions of critical flow velocity for instability, damping, natural frequency and hydrodynamic mass were used. Nearly 300 data points were assembled. The authors found that only data from experiments where all tubes are free to vibrate are valid form a design point of view. In liquids, fluid damping is important and should be considered in the formulation of fluidelastic instability. From a practical design point of view, we conclude that fluidelastic instability may be expressed simply in term of dimensionless flow velocity and dimensionless mass-damping. There is no advantage in considering more sophisticated models at this time. Practical design guidelines are discussed

  20. FASTEF Heat exchanger tube rupture CFD simulation

    International Nuclear Information System (INIS)

    The aim of this technical note is to present CFD simulations of a tube rupture incidental scenario in a Primary Heat eXchanger (PHX)/Primary Pump (PP) assembly for two design variants of the FAst-Spectrum Transmutation Experimental Facility FASTEF ongoing design, in the framework of the FP7 Central Design Team (CDT) European project. The simulation domain reproduces with some simplification the entire primary coolant loop. The objective is to understand whether it is necessary take some counter-measures to avoid the ingress of steam in the cold plenum. The simulation has been performed on two successive updates of the design and of the nominal operation. The simulations show a good resistance to steam ingress, under the condition that provision is made to avoid an excessive accumulation of steam at the top of the PHX/PP assembly casing.

  1. DEVELOPMENT OF ODS HEAT EXCHANGER TUBING

    International Nuclear Information System (INIS)

    The Vision 21 project titled ''Development of ODS Heat Exchanger Tubing'' has been initiated. A project kick-off meeting was held in Huntington, WV, the MA956 powder that will be used in the extrusion campaign has been obtained, and some of the MA956 tubing and rod required for joining trials has been shipped to the appropriate subcontractors. Acquisition of the MA956 alloy powder will allow the extrusion campaign to begin during the month of February. Also, tubing shipped to Edison Welding Institute and rod shipped to Michigan Technological University will allow joining trials to begin. In addition to these technical aspects, negotiations with all the subcontractors have been completed and the Project Management Plan and Project Work Plan have been prepared and submitted for approval

  2. Radiant heat exchange measurements for Tore Supra

    International Nuclear Information System (INIS)

    In order to minimize the energy consumption of the low temperature cryogenic system connected to the superconducting magnet of TORE-SUPRA, heat exchange from thermal radiation between the vacuum vessels and the thermal shields has been studied. Accordingly large scale cold and hot walls of T.S. have been simulated in a model with reduced dimensions. In this model, the experiment consists in the measurement of the thermal radiated power between two concentric cylindrical surfaces of stainless steel under vacuum conditions. The temperature of the external cylinder was kept constant at 80 K. The internal cylinder was bakeable up to 2500C. Various surface treatments were applied on the two cylinders (mechanical polishing and metal deposition of Al, Ag, Ni)

  3. Condensing Heat Exchanger with Hydrophilic Antimicrobial Coating

    Science.gov (United States)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor)

    2014-01-01

    A multi-layer antimicrobial hydrophilic coating is applied to a substrate of anodized aluminum, although other materials may form the substrate. A silver layer is sputtered onto a thoroughly clean anodized surface of the aluminum to about 400 nm thickness. A layer of crosslinked, silicon-based macromolecular structure about 10 nm thickness overlies the silver layer, and the outermost surface of the layer of crosslinked, silicon-based macromolecular structure is hydroxide terminated to produce a hydrophilic surface with a water drop contact angle of less than 10.degree.. The coated substrate may be one of multiple fins in a condensing heat exchanger for use in the microgravity of space, which has narrow channels defined between angled fins such that the surface tension of condensed water moves water by capillary flow to a central location where it is pumped to storage. The antimicrobial coating prevents obstruction of the capillary passages.

  4. FASTEF Heat exchanger tube rupture CFD simulation

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, V., E-mail: moreau@crs4.it [CRS4, Centre for Advanced Studies, Research and Development in Sardinia, Polaris, Edificio 1, 09010 Pula, CA (Italy)

    2012-11-15

    The aim of this technical note is to present CFD simulations of a tube rupture incidental scenario in a Primary Heat eXchanger (PHX)/Primary Pump (PP) assembly for two design variants of the FAst-Spectrum Transmutation Experimental Facility FASTEF ongoing design, in the framework of the FP7 Central Design Team (CDT) European project. The simulation domain reproduces with some simplification the entire primary coolant loop. The objective is to understand whether it is necessary take some counter-measures to avoid the ingress of steam in the cold plenum. The simulation has been performed on two successive updates of the design and of the nominal operation. The simulations show a good resistance to steam ingress, under the condition that provision is made to avoid an excessive accumulation of steam at the top of the PHX/PP assembly casing.

  5. Performance of multiple mini-tube heat exchangers as an internal heat exchanger of a vapor-injection cycle heat pump

    Science.gov (United States)

    Jang, Jin Yong; Jeong, Ji Hwan

    2015-05-01

    A multiple mini-tube (MMT) heat exchanger was considered as an internal heat exchanger of vapor-injection cycle heat pump. Heat transfer and pressure drop in multiple mini-tube heat exchangers were numerically and experimentally investigated. Results show that the best performance of the MMT heat exchanger can be obtained when the intermediate-pressure two-phase refrigerant is supplied to the shell-side and this refrigerant reaches a saturated vapor state at the exit of the heat exchanger.

  6. Thermal energy storage heat exchanger: Molten salt heat exchanger design for utility power plants

    Science.gov (United States)

    Ferarra, A.; Yenetchi, G.; Haslett, R.; Kosson, R.

    1977-01-01

    The use of thermal energy storage (TES) in the latent heat of molten salts as a means of conserving fossil fuels and lowering the cost of electric power was evaluated. Public utility systems provided electric power on demand. This demand is generally maximum during late weekday afternoons, with considerably lower overnight and weekend loads. Typically, the average demand is only 60% to 80% of peak load. As peak load increases, the present practice is to purchase power from other grid facilities or to bring older less efficient fossil-fuel plants on line which increase the cost of electric power. The widespread use of oil-fired boilers, gas turbine and diesel equipment to meet peaking loads depletes our oil-based energy resources. Heat exchangers utilizing molten salts can be used to level the energy consumption curve. The study begins with a demand analysis and the consideration of several existing modern fossil-fuel and nuclear power plants for use as models. Salts are evaluated for thermodynamic, economic, corrosive, and safety characteristics. Heat exchanger concepts are explored and heat exchanger designs are conceived. Finally, the economics of TES conversions in existing plants and new construction is analyzed. The study concluded that TES is feasible in electric power generation. Substantial data are presented for TES design, and reference material for further investigation of techniques is included.

  7. Multiple utilities targeting for heat exchanger networks

    International Nuclear Information System (INIS)

    A targeting methodology is proposed to determine the optimum loads for multiple utilities considering the cost tradeoffs in energy and capital for heat exchanger networks (HENs). The method is based on a newly-developed Cheapest Utility Principle (CUP), which simply states that it is optimal to increase the load of the cheapest utility and maintain the loads of the relatively expensive utilities constant while increasing the total utility consumption. In other words, the temperature driving forces at the utility pinches once optimized do not change even when the minimum approach temperature (?Tmin) at the process pinch is varied. The CUP holds rigorously when the relationship between the exchanger area and the capital cost is linear. Even when the relationship is non-linear, it proves to be an excellent approximation that reduces the computational effort during multiple utilities targeting. By optimizing the utility pinches sequentially and recognizing that these optimized utility pinches essentially do not change with the process ?Tmin, the results can be elegantly represented through the optimum load distribution (OLD) plots introduced in this work. (author)

  8. A new ejector heat exchanger based on an ejector heat pump and a water-to-water heat exchanger

    International Nuclear Information System (INIS)

    Highlights: • EHE is based on the reverse Carnot cycle and current heat transfer mechanisms. • EHE can decrease the return water temperature in the PHN to 35 °C. • EHE can increase the heating capacity of the existed PHN by approximately 43%. • The return water temperature in the PHN is much lower than that in the SHN. • EHE has a simpler structure, lower manufacture cost, and better regulation characteristics. - Abstract: As urban construction has been developing rapidly in China, urban heating load has been increasing continually. Heating capacity of the existed primary heating network (PHN) cannot meet district heating requirements of most metropolises in northern China. A new type of ejector heat exchanger (EHE) based on an ejector heat pump and a water-to-water heat exchanger (WWHE) was presented to increase the heating capacity of the existed PHN, and the EHE was also analyzed in terms of laws of thermodynamics. A new parameter, the exergy distribution ratio (EDR), is introduced, which is adopted to analyze regulation characteristics of the EHE. We find that the EHE shows better performance when EDR ranges from 44% to 63%. EHE can decrease the temperature of return water in the PHN to 35 °C, therefore, this can increase the heating capacity of existed PHN by about 43%. The return water with lower temperature in the PHN could recover more low-grade waste heat in industrial systems. Because of its smaller volume and lower investment, EHEs could be applied more appropriately in district heating systems for long-distance heating and waste heat district heating systems

  9. Liquid-Liquid Heat Exchanger With Zero Interpath Leakage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future manned spacecraft will require thermal management systems that effectively and safely control the temperature in inhabited modules. Interface heat exchangers...

  10. Axial flow heat exchanger devices and methods for heat transfer using axial flow devices

    Energy Technology Data Exchange (ETDEWEB)

    Koplow, Jeffrey P.

    2016-02-16

    Systems and methods described herein are directed to rotary heat exchangers configured to transfer heat to a heat transfer medium flowing in substantially axial direction within the heat exchangers. Exemplary heat exchangers include a heat conducting structure which is configured to be in thermal contact with a thermal load or a thermal sink, and a heat transfer structure rotatably coupled to the heat conducting structure to form a gap region between the heat conducting structure and the heat transfer structure, the heat transfer structure being configured to rotate during operation of the device. In example devices heat may be transferred across the gap region from a heated axial flow of the heat transfer medium to a cool stationary heat conducting structure, or from a heated stationary conducting structure to a cool axial flow of the heat transfer medium.

  11. Fouling corrosion in aluminum heat exchangers

    Directory of Open Access Journals (Sweden)

    Su Jingxin

    2015-06-01

    Full Text Available Fouling deposits on aluminum heat exchanger reduce the heat transfer efficiency and cause corrosion to the apparatus. This study focuses on the corrosive behavior of aluminum coupons covered with a layer of artificial fouling in a humid atmosphere by their weight loss, Tafel plots, electrochemical impedance spectroscopy (EIS, and scanning electron microscope (SEM observations. The results reveal that chloride is one of the major elements found in the fouling which damages the passive film and initiates corrosion. The galvanic corrosion between the metal and the adjacent carbon particles accelerates the corrosive process. Furthermore, the black carbon favors the moisture uptake, and gives the dissolved oxygen greater chance to migrate through the fouling layer and form a continuous diffusive path. The corrosion rate decreasing over time is conformed to electrochemistry measurements and can be verified by Faraday’s law. The EIS results indicate that the mechanism of corrosion can be interpreted by the pitting corrosion evolution mechanism, and that pitting was observed on the coupons by SEM after corrosive exposure.

  12. Superphenix 1 intermediate heat exchanger fabrication

    International Nuclear Information System (INIS)

    The eight Superphenix 375-MW (thermal) intermediate heat exchangers (IHXs) are similar in overall design to the Phenix components. Detailed design changes had to be made during fabrication on the following grounds: Due to seismic resistance, the support area was raised as high as possible to situate the component natural frequencies well out of the resonance peak range and remove thick plate-to-shell connections from heavy thermal load areas. Integration of lessons drawn from the Phenix incidents, due mainly to secondary sodium radial temperature disparities, resulted in the design of a more adaptable outlet header, together with a sodium mixing device, and in the reduction of temperature differences by heat insulation. To avoid circumferential temperature disparities, the iron shot biological shielding plug was replaced by stacked stainless steel plates within an outer shell, which in the new design, is not a supporting structure. The thermal-hydraulic and mechanical design of the component necessitated the elaboration of sophisticated computer codes, with validation of results on mock-ups. The detailed design studies and the actual manufacturing work had to adapt to both design developments and to inherent fabrication difficulties, mainly related to the very tight tolerances imposed for these exceptionally large components and to the welding of steel with an excessive boron content. The construction of the Creys-Malville IHXs afforded valuable industrial experience, which should provide a basis for the design of simpler and less costly IHX units for the forthcoming 1500-MW (electric) breeder

  13. Predict the temperature distribution in gas-to-gas heat pipe heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Azad, E. [Iranian Research Organization for Science and Technology, Department of Advanced Materials and Renewable Energy, Tehran (Iran, Islamic Republic of)

    2012-07-15

    A theoretical model has been developed to investigate the thermal performance of a continuous finned circular tubing of an air-to-air thermosyphon-based heat pipe heat exchanger. The model has been used to determine the heat transfer capacity, which expresses the thermal performance of heat pipe heat exchanger. The model predicts the temperature distribution in the flow direction for both evaporator and condenser sections and also the saturation temperature of the heat pipes. The approach used for the present study considers row-by-row heat-transfer in evaporator and condenser sections of the heat pipe heat exchanger. (orig.)

  14. Cardioplegia heat exchanger design modelling using computational fluid dynamics.

    Science.gov (United States)

    van Driel, M R

    2000-11-01

    A new cardioplegia heat exchanger has been developed by Sorin Biomedica. A three-dimensional computer-aided design (CAD) model was optimized using computational fluid dynamics (CFD) modelling. CFD optimization techniques have commonly been applied to velocity flow field analysis, but CFD analysis was also used in this study to predict the heat exchange performance of the design before prototype fabrication. The iterative results of the optimization and the actual heat exchange performance of the final configuration are presented in this paper. Based on the behaviour of this model, both the water and blood fluid flow paths of the heat exchanger were optimized. The simulation predicted superior heat exchange performance using an optimal amount of energy exchange surface area, reducing the total contact surface area, the device priming volume and the material costs. Experimental results confirm the empirical results predicted by the CFD analysis. PMID:11131219

  15. Measurement of flow field and local heat transfer distribution on a scraped heat exchanger crystalliser surface

    OpenAIRE

    Rodriguez, Marcos; Ravelet, Florent; Delfos, Rene; Witkamp, Geert-Jan

    2008-01-01

    In a cylindrical scraped heat exchanger crystallizer geometry the flow field influence on the local heat transfer distribution on an evenly cooled scraped heat exchanger surface has been studied by direct measurements of the heat exchanger surface temperature and the fluid velocity field inside the crystallizer. Liquid Crystal Thermometry revealed that the local heat transfer is higher in the middle area of the scraped surface. Stereoscopic PIV measurements demonstrated that the secondary flo...

  16. Power engineering, power saving and investigations on heat exchange in Russia (materials of the first Russian national conference on heat exchange)

    International Nuclear Information System (INIS)

    Review of works, presented at the 1-st Russian national conference on heat exchange and related directly to power engineering and power saving, is shown. The program of conference covered all trends in modern science on heat exchange: natural and forced convection; heat exchange by chemical transformations; boiling; boiling crisis and beyond-the-crisis heat exchange; two-phase flows; evaporation and condensation; dispersion flows and porous media; heat exchange intensification; radiation and complex heat exchange; thermal conductivity and thermal insulation

  17. Vertical drum heat exchanger for overheated steam production

    International Nuclear Information System (INIS)

    The heat exchange surface of the heat exchanger consists on the primary side of vertical parallel heat transfer tubes with the feeder channel for the water/steam mixture to the steam separators and of a discharge steam channel from the separators. On the secondary side of the heat transfer tubes the heat exchanger is provided with a partition which runs across all tubes. The feeder channel to the separators is connected to the area between the tubes immediately under the partition and the discharge channel immediately above the partition. (M.D.)

  18. Simulation Studies on A Cross Flow Plate Fin Heat Exchanger

    OpenAIRE

    Thirumarimurugan, M.; T Kannadasan; E. Ramasamy

    2008-01-01

    Compact heat exchangers which were initially developed for the aerospace industries in the1940s have been considerably improved in the past few years. The main reasons for the goodperformance of compact heat exchangers are their special design which includes turbulent which inturn use high heat transfer coefficient and resists fouling, and maximum temperature driving forcebetween the hot and cold fluids. Numerous types use special enhancement techniques to achieve therequired heat transfer in...

  19. A Liquid-Liquid Thermoelectric Heat Exchanger as a Heat Pump for Testing Phase Change Material Heat Exchangers

    Science.gov (United States)

    Sheth, Rubik B.; Makinen, Janice; Le, Hung V.

    2016-01-01

    The primary objective of the Phase Change HX payload on the International Space Station (ISS) is to test and demonstrate the viability and performance of Phase Change Material Heat Exchangers (PCM HX). The system was required to pump a working fluid through a PCM HX to promote the phase change material to freeze and thaw as expected on Orion's Multipurpose Crew Vehicle. Due to limitations on ISS's Internal Thermal Control System, a heat pump was needed on the Phase Change HX payload to help with reducing the working fluid's temperature to below 0degC (32degF). This paper will review the design and development of a TEC based liquid-liquid heat exchanger as a way to vary to fluid temperature for the freeze and thaw phase of the PCM HX. Specifically, the paper will review the design of custom coldplates and sizing for the required heat removal of the HX.

  20. Heat Recovery Ventilation for Housing: Air-to-Air Heat Exchangers.

    Science.gov (United States)

    Corbett, Robert J.; Miller, Barbara

    The air-to-air heat exchanger (a fan powered ventilation device that recovers heat from stale outgoing air) is explained in this six-part publication. Topic areas addressed are: (1) the nature of air-to-air heat exchangers and how they work; (2) choosing and sizing the system; (3) installation, control, and maintenance of the system; (4) heat…

  1. WASTE HEAT RECOVERY FROM BOILER OF LARGE-SCALE TEXTILE INDUSTRY

    Directory of Open Access Journals (Sweden)

    Prateep Pattanapunt

    2013-01-01

    Full Text Available Many industrial heating processes generate waste energy in textile industry; especially exhaust gas from the boiler at the same time reducing global warming. Therefore, this article will present a study the way to recovery heat waste from boiler exhaust gas by mean of shell and tube heat exchanger. Exhaust gas from boiler dyeing process, which carries a large amount of heat, energy consumptions could be decrease by using of waste-heat recovery systems. In this study, using ANASYS simulation performs a thermodynamics analysis. An energy-based approach is performed for optimizing the effective working condition for waste-heat recovery with exhaust gas to air shell and tube heat exchanger. The variations of parameters, which affect the system performance such as, exhaust gas and air temperature, velocity and mass flow rate and moisture content is examined respectively. From this study, it was found that heat exchanger could be reduced temperature of exhaust gases and emission to atmosphere and the time payback is the fastest. The payback period was determined about 6 months for investigated ANSYS. The air is circulated in four passes from the top to the bottom of the test section, in overall counter-flow with exhaust gas. The front area is 1720×1720 mm, the flow length 7500 mm, the inner and outer diameter of exhaust gas is 800 mm, the tube assembly consist of 196 tubes, the tube diameter is 76.2 mm, the tube thickness is 2.6 mm, the tube length is 4500 mm, the tube length of air inner and outer is 500 mm. The result show that, the boiler for superheated type there are exhaust gas temperature is 190°C, 24% the moisture content of fuel and there are palm kernel shell 70 tons day-1 which there are the high temperature after the heat exchanger, 150°C. It was occurred acid rain. The hot air from heat exchanger process can be reduced the moisture of palm kernel shell fuel to 15%.The fuel consumption is reduced by about 2.05% (322.72 kJ kg-1, while the shell and tube heat exchanger outlet exhaust gas temperature decreases from 190 to 150°C.

  2. Development of heat resistant ion exchange resin. First Report

    International Nuclear Information System (INIS)

    In nuclear power stations, as a means of maintaining the soundness of nuclear reactors, the cleaning of reactor cooling water has been carried out. But as for the ion exchange resin which is used as the cleaning agent in the filtrating and desalting facility in reactor water cleaning system, since the heat resistance is low, high temperature reactor water is cooled once and cleaned, therefore large heat loss occurs. If the cleaning can be done at higher temperature, the reduction of heat loss and compact cleaning facilities become possible. In this study, a new ion exchange resin having superior heat resistance has been developed, and the results of the test of evaluating the performance of the developed ion exchange resin are reported. The heat loss in reactor water cleaning system, the heat deterioration of conventional ion exchange resin, and the development of the anion exchange resin of alkyl spacer type are described. The outline of the performance evaluation test, the experimental method, and the results of the heat resistance, ion exchange characteristics and so on of C4 resin are reported. The with standable temperature of the developed anion exchange resin was estimated as 80 - 90degC. The ion exchange performance at 95degC of this resin did not change from that at low temperature in chloride ions and silica, and was equivalent to that of existing anion exchange resin. (K.I.)

  3. Advanced heat exchanger development for molten salts

    Energy Technology Data Exchange (ETDEWEB)

    Sabharwall, Piyush, E-mail: Piyush.Sabharwall@inl.gov [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Clark, Denis; Glazoff, Michael [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Zheng, Guiqiu; Sridharan, Kumar; Anderson, Mark [University of Wisconsin, Madison (United States)

    2014-12-15

    Highlights: • Hastelloy N and 242, shows corrosion resistance to molten salt at nominal operating temperatures. • Both diffusion welds and sheet material in Hastelloy N were corrosion tested in at 650, 700, and 850 °C for 200, 500, and 1000 h. • Thermal gradients and galvanic couples in the molten salts enhance corrosion rates. • Corrosion rates found were typically <10 mils per year. - Abstract: This study addresses present work concerned with advanced heat exchanger development for molten salt in nuclear and non-nuclear thermal systems. The molten salt systems discussed herein use alloys, such as Hastelloy N and 242, that show good corrosion resistance in molten salt at nominal operating temperatures up to 700 °C. These alloys were diffusion welded, and the corresponding information is presented. Test specimens were prepared for exposing diffusion welds to molten salt environments. Hastelloy N and 242 were found to be weldable by diffusion welding, with ultimate tensile strengths about 90% of base metal values. Both diffusion welds and sheet material in Hastelloy N were corrosion tested in 58 mol% KF and 42 mol% ZrF{sub 4} at 650, 700, and 850 °C for 200, 500, and 1000 h. Corrosion rates were similar between welded and nonwelded materials, typically <100 ?m per year after 1000 h of corrosion tests. No catastrophic corrosion was observed in the diffusion welded regions. For materials of construction, nickel-based alloys and alloys with dense nickel coatings are effectively inert to corrosion in fluorides, but not so in chlorides. Hence, additional testing of selected alloys for resistance to intergranular corrosion is needed, as is a determination of corrosion rate as a function of the type of salt impurity and alloy composition, with respect to chromium and carbon, to better define the best conditions for corrosion resistance. Also presented is the division of the nuclear reactor and high-temperature components per American Society of Mechanical Engineers (ASME) standards, along with design requirements for a subcritical Rankine power cycle heat exchanger that has to overcome pressure difference of about 17 MPa.

  4. Advanced heat exchanger development for molten salts

    International Nuclear Information System (INIS)

    Highlights: • Hastelloy N and 242, shows corrosion resistance to molten salt at nominal operating temperatures. • Both diffusion welds and sheet material in Hastelloy N were corrosion tested in at 650, 700, and 850 °C for 200, 500, and 1000 h. • Thermal gradients and galvanic couples in the molten salts enhance corrosion rates. • Corrosion rates found were typically <10 mils per year. - Abstract: This study addresses present work concerned with advanced heat exchanger development for molten salt in nuclear and non-nuclear thermal systems. The molten salt systems discussed herein use alloys, such as Hastelloy N and 242, that show good corrosion resistance in molten salt at nominal operating temperatures up to 700 °C. These alloys were diffusion welded, and the corresponding information is presented. Test specimens were prepared for exposing diffusion welds to molten salt environments. Hastelloy N and 242 were found to be weldable by diffusion welding, with ultimate tensile strengths about 90% of base metal values. Both diffusion welds and sheet material in Hastelloy N were corrosion tested in 58 mol% KF and 42 mol% ZrF4 at 650, 700, and 850 °C for 200, 500, and 1000 h. Corrosion rates were similar between welded and nonwelded materials, typically <100 ?m per year after 1000 h of corrosion tests. No catastrophic corrosion was observed in the diffusion welded regions. For materials of construction, nickel-based alloys and alloys with dense nickel coatings are effectively inert to corrosion in fluorides, but not so in chlorides. Hence, additional testing of selected alloys for resistance to intergranular corrosion is needed, as is a determination of corrosion rate as a function of the type of salt impurity and alloy composition, with respect to chromium and carbon, to better define the best conditions for corrosion resistance. Also presented is the division of the nuclear reactor and high-temperature components per American Society of Mechanical Engineers (ASME) standards, along with design requirements for a subcritical Rankine power cycle heat exchanger that has to overcome pressure difference of about 17 MPa

  5. Influence of supercritical ORC parameters on plate heat exchanger design

    International Nuclear Information System (INIS)

    The applications of Organic Rankine Cycle (ORC) appear to be growing in the field of waste heat utilization. This thermodynamic cycle can be successfully used in the field of biomass combustion, geothermal systems or solar desalination systems, providing efficient systems. In the last years, a very intense investigation on the utilization of low temperature waste heat for supplying ORC systems has brought new research potential in the area of thermodynamic optimisation of this cycle. More specifically, the use of supercritical fluid parameters in the ORC processes seems to become more and more attractive leading to lower exergy destruction systems together with higher heat utilization systems. However, the investigation of the heat exchanger design and the heat exchange coefficients is of high importance for these applications as the effective heat transfer reflects on the overall process energetic and exergetic efficiency. It is important to study the relatively unknown heat transfer mechanisms around the critical point to improve both the heat exchanger surface and the design algorithms. The aim of this paper is to investigate the influence of the ORC parameters on the heat exchanger design. More specifically, the basic parameters of the design of the heat exchangers will be defined in the cases of supercritical fluid parameters and the convective coefficients as well as resulting heat transfer surface will be calculated for various fluid parameters. - Highlights: ? Optimisation of the heat exchanger partitioning. ? Comparison of proposed correlations for calculating heat transfer coefficients. ? Calculation of the heat transfer coefficients under supercritical fluid parameters. ? Calculation of the necessary heat transfer surface. ? Calculation of the heat exchanger efficiency under supercritical fluid parameters.

  6. Refrigeration system performance using liquid-suction heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Klein, S.A.; Reindl, D.T.; Brownell, K. [Wisconsin Univ., Dept. of Mechanical Engineering, Madison, WI (United States)

    2000-07-01

    Heat transfer devices are provided in many refrigeration systems to exchange energy between the cool gaseous refrigerant leaving the evaporator and warm liquid refrigerant exiting the condenser. These liquid-suction or suction-line heat exchangers can, in some cases, yield improved system performance while in other cases they degrade system performance. Although previous researchers have investigated performance of liquid-suction heat exchangers, this study can be distinguished from the previous studies in three ways. First, this paper identifies a new dimensionless group to correlate performance impacts attributable to liquid-suction heat exchangers. Second, the paper extends previous analyses to include new refrigerants. Third, the analysis includes the impact of pressure drops through the liquid-suction heat exchanger on system performance. It is shown that reliance on simplified analysis techniques can lead to inaccurate conclusions regarding the impact of liquid-suction heat exchangers on refrigeration system performance. From detailed analyses, it can be concluded that liquid-suction heat exchangers that have a minimal pressure loss on the low pressure side are useful for systems using R507A, R134a, R12, R404A, R290, R407C, R600, and R410A. The liquid-suction heat exchanger is detrimental to system performance in systems using R22, R32, and R717. (Author)

  7. THERMAL ANALYSIS OF EARTH AIR HEAT EXCHANGER USING CFD

    Directory of Open Access Journals (Sweden)

    Vaibhav Madane

    2015-05-01

    Full Text Available This project focuses on Earth Air Heat Exchanger which is reducing energy consumption in a building. The air is passing through the buried tubes and heat exchange takes place between air and surrounding soil. This equipment helps to reduce energy consumption of an air conditioning unit. This project analyses the thermal performance of earth air heat exchanger by using computational fluid dynamics modeling. The model is validated against experimental observations and investigations on an experimental setup in Ajmer. Simulation results are in fair agreement with experimental data. Effects of pipe materials on thermal performance of earth air heat exchangers are also studied for summer conditions in Mumbai. Results have shown that the performance of earth air heat exchanger is not significantly affected by material of buried pipes.

  8. The heat exchanger of small pellet boiler for phytomass

    Science.gov (United States)

    Mi?ieta, Jozef; Lenhard, Richard; Janda?ka, Jozef

    2014-08-01

    Combustion of pellets from plant biomass (phytomass) causes various troubles. Main problem is slagging ash because of low melting temperature of ash from phytomass. This problem is possible to solve either improving energetic properties of phytomass by additives or modification of boiler construction. A small-scale boiler for phytomass is different in construction of heat exchanger and furnace mainly. We solve major problem - slagging ash, by decreasing combustion temperature via redesign of pellet burner and boiler body. Consequence of lower combustion temperature is also lower temperature gradient of combustion gas. It means that is necessary to design larger heat exchanging surface. We plane to use underfed burner, so we would utilize circle symmetry heat exchanger. Paper deals design of heat exchanger construction with help of CFD simulation. Our purpose is to keep uniform water flux and combustion gas flux in heat exchanger without zone of local overheating and excess cooling.

  9. A concept of PWR using plate and shell heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Freire, Luciano Ondir; Andrade, Delvonei Alves de, E-mail: luciano.ondir@gmail.com, E-mail: delvonei@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    In previous work it was verified the physical possibility of using plate and shell heat exchangers for steam generation in a PWR for merchant ships. This work studies the possibility of using GESMEX commercial of the shelf plate and shell heat exchanger of series XPS. It was found it is feasible for this type of heat exchanger to meet operational and accidental requirements for steam generation in PWR. Additionally, it is proposed an arrangement of such heat exchangers inside the reactor pressure vessel. Such arrangement may avoid ANSI/ANS51.1 nuclear class I requirements on those heat exchangers because they are contained in the reactor coolant pressure barrier and play no role in accidental scenarios. Additionally, those plates work under compression, preventing the risk of rupture. Being considered non-nuclear safety, having a modular architecture and working under compression may turn such architectural choice a must to meet safety objectives with improved economics. (author)

  10. Self-defrosting recuperative air-to-air heat exchanger

    Science.gov (United States)

    Drake, Richard L. (Delmar, NY)

    1993-01-01

    A heat exchanger includes a stationary spirally or concentrically wound heat exchanger core with rotating baffles on upper and lower ends thereof. The rotating baffles include rotating inlets and outlets which are in communication with respective fixed inlets and outlets via annuli. The rotation of the baffles causes a concurrent rotation of the temperature distribution within the stationary exchanger core, thereby preventing frost build-up in some applications and preventing the formation of hot spots in other applications.

  11. Dynamic responses of heat exchanger tube banks

    International Nuclear Information System (INIS)

    Understanding and modeling fluid/structure interaction in cylinder bundles is a basic requirement in the development of analytical methods and guidelines for designing LMFBR heat exchanger and reactor fuel assemblies that are free from component vibration problems. As a step toward satisfying this requirement, an analytical and experimental study of tube banks vibrating in liquids is presented. A general method of analysis is presented for free and forced vibrations of tube banks including tube/fluid interaction, and numerical results are given for tube banks subjected to various types of excitations. Two cantilevered tubes were tested in a water tank, and the natural frequencies and forced responses of coupled motion were measured. Experimental data and analytical results are in reasonably good agreement. The analytical method presented is currently being extended to account for the flowing fluid in tube banks and will be used in the development of the mathematical models for crossflow- and parallel-flow-induced vibrations of tube bundles. Those models will be useful in predicting the response of tube bundles and in design to avoid detrimental vibration

  12. Thermal hydraulic analysis for the design of intermediate heat exchanger

    International Nuclear Information System (INIS)

    Prototype Fast Breeder Reactor (PFBR) is a sodium cooled reactor with 500MWe(1210MWt) capacity. Nuclear heat generated in the core is transferred to primary sodium flowing through the subassemblies. The hot primary sodium exchanges heat with secondary sodium through intermediate heat exchangers. A two dimensional analysis of the intermediate heat exchanger has clearly brought out the high values of radial temperature drop of primary and secondary sodium streams when the secondary flow is uniform. A solution of unequal secondary flow has proved to be an effective method to reduce the temperature drops leading to a safer design. (author). 7 refs., 5 figs

  13. CFD Based Evaluation Of Effectiveness Of Counter Flow Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Gurpreet Kour

    2014-04-01

    Full Text Available Engineers are continually being asked to improve effectiveness of heat transfer equipments. These requests may arise as a result of the need to increase profitability or accommodate capital limitations. Processes which use heat transfer equipment i.e. heat exchanger must frequently be improved for these reasons. Artifical roughness is important technique for enhancing the effectiveness of heat exchanger. In this work effectiveness of smooth as well as roughened tube in heat exchanger is theoretically investigated by using ring type roughness geometry. The performance obtained is then compared with smooth tube. Ringed tube has a significant effect on effectiveness of heat exchanger. The effectiveness is 3.2 times as compared with plane tube was reported. The effectiveness found to be increased with increasing roughness and decreasing pitch between the rings.

  14. Test results of a Stirling engine utilizing heat exchanger modules with an integral heat pipe

    Science.gov (United States)

    Skupinski, Robert C.; Tower, Leonard K.; Madi, Frank J.; Brusk, Kevin D.

    1993-01-01

    The Heat Pipe Stirling Engine (HP-1000), a free-piston Stirling engine incorporating three heat exchanger modules, each having a sodium filled heat pipe, has been tested at the NASA-Lewis Research Center as part of the Civil Space Technology Initiative (CSTI). The heat exchanger modules were designed to reduce the number of potential flow leak paths in the heat exchanger assembly and incorporate a heat pipe as the link between the heat source and the engine. An existing RE-1000 free-piston Stirling engine was modified to operate using the heat exchanger modules. This paper describes heat exchanger module and engine performance during baseline testing. Condenser temperature profiles, brake power, and efficiency are presented and discussed.

  15. Optimized heat exchanger unit in a thermoacoustic refrigerator

    Science.gov (United States)

    El-Fawal, Mawahib Hassan; Mohd-Ghazali, Normah

    2012-06-01

    Due to concern over the environmental impact caused by hazardous refrigerants, the last ten years or so has seen increasing research into thermoacoustic refrigeration. A thermoacoustic refrigerator is a device which uses acoustic power to pump heat. It holds the merits of simple mechanical design, absence of harmful refrigerants and having no or few moving parts. However, the performance of the thermoacoustic refrigerator, particularly the standing wave types, is currently not competitive compared to its counterpart conventional vapor-compression refrigerator. Thermoacoustic refrigeration prototypes, built up-to-date, achieved 0.1-0.2 relative coefficient of performance (COPR) compared with that of 0.33-0.5 for the conventional vapor-compression refrigerators. The poor heat exchanger design is one of the reasons for this poor efficiency. This paper discussed the influence of the thermoacoustic refrigerator heat exchanger's parameters on its design and the optimization of the performance of the system using the Lagrange multiplier method. The results showed that, the dissipated power is less than the published value by about 49% in the cold heat exchanger and about 38.5% in the hot heat exchanger. Furthermore, the increase of the cold heat exchanger effectiveness is found to be 3%. Thus, the decrease in the dissipated power in both heat exchangers with effective cold heat exchanger increases the performance of the thermoacoustic refrigerator.

  16. Heat exchanger and method of making. [rocket lining

    Science.gov (United States)

    Fortini, A.; Kazaroff, J. M. (Inventor)

    1980-01-01

    A heat exchange of increased effectiveness is disclosed. A porous metal matrix is disposed in a metal chamber or between walls through which a heat-transfer fluid is directed. The porous metal matrix has internal bonds and is bonded to the chamber in order to remove all thermal contact resistance within the composite structure. Utilization of the invention in a rocket chamber is disclosed as a specific use. Also disclosed is a method of constructing the heat exchanger.

  17. Characteristics of Vertical Mantle Heat Exchangers for Solar Water Heaters

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Morrison, G.L.; Behnia, M.

    1999-01-01

    - The flow structure in vertical mantle heat exchangers was investigated using a full-scale tank designed to facilitate flow visualisation. The flow structure and velocities in the mantle were measured using a particle Image Velocimetry (PIV) system. A CFD simulation model of vertical mantle heat exchangers was also developed for detailed evaluation of the heat flux distribution over the mantle surface. Both the experimental and simulation results indicate that distribution of the flow around th...

  18. SILICON CARBIDE CERAMICS FOR COMPACT HEAT EXCHANGERS

    Energy Technology Data Exchange (ETDEWEB)

    DR. DENNIS NAGLE; DR. DAJIE ZHANG

    2009-03-26

    Silicon carbide (SiC) materials are prime candidates for high temperature heat exchangers for next generation nuclear reactors due to their refractory nature and high thermal conductivity at elevated temperatures. This research has focused on demonstrating the potential of liquid silicon infiltration (LSI) for making SiC to achieve this goal. The major advantage of this method over other ceramic processing techniques is the enhanced capability of making high dense, high purity SiC materials in complex net shapes. For successful formation of net shape SiC using LSI techniques, the carbon preform reactivity and pore structure must be controlled to allow the complete infiltration of the porous carbon structure which allows complete conversion of the carbon to SiC. We have established a procedure for achieving desirable carbon properties by using carbon precursors consisting of two readily available high purity organic materials, crystalline cellulose and phenolic resin. Phenolic resin yields a glassy carbon with low chemical reactivity and porosity while the cellulose carbon is highly reactive and porous. By adjusting the ratio of these two materials in the precursor mixtures, the properties of the carbons produced can be controlled. We have identified the most favorable carbon precursor composition to be a cellulose resin mass ratio of 6:4 for LSI formation of SiC. The optimum reaction conditions are a temperature of 1800 C, a pressure of 0.5 Torr of argon, and a time of 120 minutes. The fully dense net shape SiC material produced has a density of 2.96 g cm{sup -3} (about 92% of pure SiC) and a SiC volume fraction of over 0.82. Kinetics of the LSI SiC formation process was studied by optical microscopy and quantitative digital image analysis. This study identified six reaction stages and provided important understanding of the process. Although the thermal conductivity of pure SiC at elevated temperatures is very high, thermal conductivities of most commercial SiC materials are much lower due to phonon scattering by impurities (e.g., sintering aids located at the grain boundaries of these materials). The thermal conductivity of our SiC was determined using the laser flash method and it is 214 W/mK at 373 K and 64 W/mK at 1273 K. These values are very close to those of pure SiC and are much higher than those of SiC materials made by industrial processes. This SiC made by our LSI process meets the thermal properties required for use in high temperature heat exchanger. Cellulose and phenolic resin carbons lack the well-defined atomic structures associated with common carbon allotropes. Atomic-scale structure was studied using high resolution transmission electron microscopy (HRTEM), nitrogen gas adsorption and helium gas pycnometry. These studies revealed that cellulose carbon exhibits a very high degree of atomic disorder and angstrom-scale porosity. It has a density of only 93% of that of pure graphite, with primarily sp2 bonding character and a low concentration of graphene clusters. Phenolic resin carbon shows more structural order and substantially less angstrom-scale porosity. Its density is 98% of that of pure graphite, and Fourier transform analysis of its TEM micrographs has revealed high concentrations of sp3 diamond and sp2 graphene nano-clusters. This is the first time that diamond nano-clusters have been observed in carbons produced from phenolic resin. AC and DC electrical measurements were made to follow the thermal conversion of microcrystalline cellulose to carbon. This study identifies five regions of electrical conductivity that can be directly correlated to the chemical decomposition and microstructural evolution during carbonization. In Region I, a decrease in overall AC conductivity occurs due to the initial loss of the polar groups from cellulose molecules. In Region II, the AC conductivity starts to increase with heat treatment temperature due to the formation and growth of conducting carbon clusters. In Region III, a further increase of AC conductivity with increasing heat treatment temperature is observed. In addition, the AC conductivity demonstrates a non-linear frequency dependency due to electron hopping, interfacial polarization, and onset of a percolation threshold. In Region IV, the DC conductivity continues to increase with heat treatment due to the growth and percolation of carbon clusters. Finally in Region V, the DC conductivity reaches a plateau with increasing heat treatment temperature as the system reaches a fully percolated state. Thermophysical properties of carbon materials derived from microcrystalline cellulose have been measured under vacuum and compared with earlier measurements conducted under nitrogen to better understand the influence of porosity, composition, and atmosphere effects. The effective thermal conductivity in vacuum is lower than that observed in nitrogen primarily due to the conductivity of nitrogen gas.

  19. SILICON CARBIDE CERAMICS FOR COMPACT HEAT EXCHANGERS

    International Nuclear Information System (INIS)

    Silicon carbide (SiC) materials are prime candidates for high temperature heat exchangers for next generation nuclear reactors due to their refractory nature and high thermal conductivity at elevated temperatures. This research has focused on demonstrating the potential of liquid silicon infiltration (LSI) for making SiC to achieve this goal. The major advantage of this method over other ceramic processing techniques is the enhanced capability of making high dense, high purity SiC materials in complex net shapes. For successful formation of net shape SiC using LSI techniques, the carbon preform reactivity and pore structure must be controlled to allow the complete infiltration of the porous carbon structure which allows complete conversion of the carbon to SiC. We have established a procedure for achieving desirable carbon properties by using carbon precursors consisting of two readily available high purity organic materials, crystalline cellulose and phenolic resin. Phenolic resin yields a glassy carbon with low chemical reactivity and porosity while the cellulose carbon is highly reactive and porous. By adjusting the ratio of these two materials in the precursor mixtures, the properties of the carbons produced can be controlled. We have identified the most favorable carbon precursor composition to be a cellulose resin mass ratio of 6:4 for LSI formation of SiC. The optimum reaction conditions are a temperature of 1800 C, a pressure of 0.5 Torr of argon, and a time of 120 minutes. The fully dense net shape SiC material produced has a density of 2.96 g cm-3 (about 92% of pure SiC) and a SiC volume fraction of over 0.82. Kinetics of the LSI SiC formation process was studied by optical microscopy and quantitative digital image analysis. This study identified six reaction stages and provided important understanding of the process. Although the thermal conductivity of pure SiC at elevated temperatures is very high, thermal conductivities of most commercial SiC materials are much lower due to phonon scattering by impurities (e.g., sintering aids located at the grain boundaries of these materials). The thermal conductivity of our SiC was determined using the laser flash method and it is 214 W/mK at 373 K and 64 W/mK at 1273 K. These values are very close to those of pure SiC and are much higher than those of SiC materials made by industrial processes. This SiC made by our LSI process meets the thermal properties required for use in high temperature heat exchanger. Cellulose and phenolic resin carbons lack the well-defined atomic structures associated with common carbon allotropes. Atomic-scale structure was studied using high resolution transmission electron microscopy (HRTEM), nitrogen gas adsorption and helium gas pycnometry. These studies revealed that cellulose carbon exhibits a very high degree of atomic disorder and angstrom-scale porosity. It has a density of only 93% of that of pure graphite, with primarily sp2 bonding character and a low concentration of graphene clusters. Phenolic resin carbon shows more structural order and substantially less angstrom-scale porosity. Its density is 98% of that of pure graphite, and Fourier transform analysis of its TEM micrographs has revealed high concentrations of sp3 diamond and sp2 graphene nano-clusters. This is the first time that diamond nano-clusters have been observed in carbons produced from phenolic resin. AC and DC electrical measurements were made to follow the thermal conversion of microcrystalline cellulose to carbon. This study identifies five regions of electrical conductivity that can be directly correlated to the chemical decomposition and microstructural evolution during carbonization. In Region I, a decrease in overall AC conductivity occurs due to the initial loss of the polar groups from cellulose molecules. In Region II, the AC conductivity starts to increase with heat treatment temperature due to the formation and growth of conducting carbon clusters. In Region III, a further increase of AC conductivity with increasing heat treatment temperature is observed. In addition, the AC conductivity demonstrates a non-linear frequency dependency due to electron hopping, interfacial polarization, and onset of a percolation threshold. In Region IV, the DC conductivity continues to increase with heat treatment due to the growth and percolation of carbon clusters. Finally in Region V, the DC conductivity reaches a plateau with increasing heat treatment temperature as the system reaches a fully percolated state. Thermophysical properties of carbon materials derived from microcrystalline cellulose have been measured under vacuum and compared with earlier measurements conducted under nitrogen to better understand the influence of porosity, composition, and atmosphere effects. The effective thermal conductivity in vacuum is lower than that observed in nitrogen primarily due to the conductivity of nitrogen gas

  20. Flat tube heat exchangers – Direct and indirect noise levels in heat pump applications

    International Nuclear Information System (INIS)

    In the outdoor unit of an air-source heat pump the fan is a major noise source. The noise level from the fan is dependent on its state of operation: high air-flow and high pressure drop often result in higher noise levels. In addition, an evaporator that obstructs an air flow is a noise source in itself, something that may contribute to the total noise level. To be able to reduce the noise level, heat exchanger designs other than the common finned round tubes were investigated in this study. Three types of heat exchanger were evaluated to detect differences in noise level and air-side heat transfer performance at varying air flow. The measured sound power level from all the heat exchangers was low in comparison to the fan sound power level (direct effect). However, the heat exchanger design was shown to have an important influence on the sound power level from the fan (indirect effect). One of the heat exchangers with flat tubes was found to have the lowest sound power level, both direct and indirect, and also the highest heat transfer rate. This type of flat tube heat exchanger has the potential to reduce the overall noise level of a heat pump while maintaining heat transfer efficiency. - Highlights: •The direct noise from a heat exchanger is negligible in heat pump applications. •The design of the heat exchanger highly influences the noise from an outdoor unit. •Flat tube heat exchangers can reduce the noise from the outdoor unit of a heat pump. •Flat tube heat exchangers can increase the energy efficiency of a heat pump

  1. Performance studies on high temperature sodium to air heat exchangers

    International Nuclear Information System (INIS)

    It has been observed that design of high temperature sodium to air heat exchanger has some uncertainties which have led to poor heat transfer performance in the past. The study of such heat exchangers is important to avoid excessive temperature build up in the reactor as decay heat removal exchangers for the prototype fast breeder reactor are to be of this design. A computer program has been developed for design of transverse finned U tube cross flow type of heat exchanger with two or more passes on the tube side. The paper deals with the features of construction of a typical sodium to air heat exchanger, types of finned tubes commonly used with comparison of different types of connection of fins to tubes. The improvements carried out during the design of second sodium to air heat exchanger to improve heat transfer performance have been highlighted. The effect of variation of few important parameters on the heat transfer performance and pressure drop has been elucidated. 7 refs., 2 tabs., 3 figs

  2. Numerical simulation of fluid flow and heat transfer in a concentric tube heat exchanger

    International Nuclear Information System (INIS)

    In this paper, numerical simulation of a concentric tube heat exchanger is presented to determine the convective heat transfer coefficient and friction factor in a smooth tube. Increasing the convective heat transfer coefficient can increase heat transfer rate in a concentric tube heat exchanger from a given tubular surface area. This can be achieved by using heat transfer augmentation devices. This work constitutes the initial phase of the numerical simulation of heat transfer from tubes employing augmentation devices, such as twisted tapes, wire-coil inserts, for heat transfer enhancement. A computational fluid dynamics (CFD) simulation tool was developed with CFX software and the results obtained from the simulations are validated with the empirical correlations for a smooth tube heat exchanger. The difficulties associated with the simulation of a heat exchanger augmented with wire-coil inserts are discussed. (author)

  3. Studies on a heat exchanger producting subcooled liquid helium

    International Nuclear Information System (INIS)

    A heat exchanger for cooling the TRISTAN final focusing superconducting quadrupole magnet was studied. This heat exchanger could produce subcooled liquid helium of 20 g/s and 0. 16 MPa below 4.4 K with saturated liquid helium at 0.11 MPa. For the heat transfer of single phase flow in the heat exchanger, the calculations with the Dittus-Boelter and Kutateladze equations agreed well with the measurements. For the heat transfer during the condensation process, the Shah equation including vapor quality was applied. The calculated heat transfer energy was twice as large as the measured value and the vapor effect on the heat transfer coefficient was not as large as that calculated by the Shah equation

  4. Investigation of Brazed Plate Heat Exchangers With Variable Chevron Angles

    Directory of Open Access Journals (Sweden)

    S. Muthuraman

    2013-08-01

    Full Text Available - Experiments to measure the condensation heat transfer coefficient and the pressure drop in brazed plate heat exchangers (BPHEs were performed with the refrigerants R410A and R22. Brazed plate heat exchangers with different chevron angles of 45°, 35°, and 20° were used. Varying the mass flux, the condensation temperature, and the vapor quality of the refrigerant, we measured the condensation heat transfer coefficient and the pressure drops. Both the heat transfer coefficient and the pressure drop increased proportionally with the mass flux and the vapor quality and inversely with the condensation temperature and the chevron angle.

  5. Performance of tubes-and plate fins heat exchangers

    International Nuclear Information System (INIS)

    By means of a two-dimensional analysis performance, and using local heat transfer coefficients, the plate fin temperature distribution, the air bulk temperature along the stream path and the fin efficiency can be obtained, for several Reynolds numbers and fin materials. Herein are also presented the average heat transfer coefficients for isothermal plate fins, referring to heat exchangers with central-tube and rear-tube row and to two-row tubes heat exchangers configurations. It is possible to obtain the real tax or the real area of heat transfer, using the average hea transfer coefficients for isothermal plate fins and the fin efficiency. (Author)

  6. Improvements of U-pipe Borehole Heat Exchangers

    OpenAIRE

    Acuña, José

    2010-01-01

    The sales of Ground Source Heat Pumps in Sweden and many other countries are having a rapid growth in the last decade. Today, there are approximately 360 000 systems installed in Sweden, with a growing rate of about 30 000 installations per year. The most common way to exchange heat with the bedrock in ground source heat pump applications is circulating a secondary fluid through a Borehole Heat Exchanger (BHE), a closed loop in a vertical borehole. The fluid transports the heat from the groun...

  7. Integrated system of nuclear reactor and heat exchanger

    International Nuclear Information System (INIS)

    The invention concerns PWRs in which the heat exchanger is associated with a pressure vessel containing the core and from which it can be selectively detached. This structural configuration applies to electric power generating uses based on land or on board ships. An existing reactor of this kind is fitted with a heat exchanger in which the tubes are 'U' shaped. This particular design of heat exchangers requires that the ends of the curved tubes be solidly maintained in a tube plate of great thickness, hence difficult to handle and to fabricate and requiring unconventional fine control systems for the control rods and awkward coolant pump arrangements. These complications limit the thermal power of the system to level below 100 megawatts. On the contrary, the object of this invention is to provide a one-piece PWR reactor capable of reaching power levels of 1500 thermal megawatts at least. For this, a pressure vessel is provided in the cylindrical assembly with not only a transversal separation on a plane located between the reactor and the heat exchanger but also a cover selectively detachable which supports the fine control gear of the control rods. Removing the cover exposes a part of the heat exchanger for easy inspection and maintenance. Further, the heat exchanger can be removed totally from the pressure vessel containing the core by detaching the cylindrical part, which composes the heat exchanger section, from the part that holds the reactor core on a level with the transversal separation

  8. Heat Exchange and Thermal Modes of Modern Ring Furnaces

    Directory of Open Access Journals (Sweden)

    V. I. Timoshpolsky

    2014-06-01

    Full Text Available The paper considers an accumulated experience concerning investigation of heat exchange and thermal modes of ring furnaces applied for heating simulation. Physical and mathematical model and methodology for theoretical investigation of round billet heating in the ring furnace are proposed in the paper.

  9. Temperatures and Heat Flows in a Soil Enclosing a Slinky Horizontal Heat Exchanger

    OpenAIRE

    Pavel Neuberger; Radomír Adamovský; Michaela Še?ová

    2014-01-01

    Temperature changes and heat flows in soils that host “slinky”-type horizontal heat exchangers are complex, but need to be understood if robust quantification of the thermal energy available to a ground-source heat pump is to be achieved. Of particular interest is the capacity of the thermal energy content of the soil to regenerate when the heat exchangers are not operating. Analysis of specific heat flows and the specific thermal energy regime within the soil, including that captured by the ...

  10. Thermal behavior of a heat exchanger module for seasonal heat storage

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon; Andersen, Elsa; Chen, Ziqian; Perers, Bengt; Dannemand, Mark

    2012-01-01

    Experimental and theoretic investigations are carried out to study the heat transfer capacity rate of a heat exchanger module for seasonal heat storage with sodium acetate trihydrate (SAT) supercooling in a stable way. A sandwich heat storage test module has been built with the phase change material (PCM) storage box in between two plate heat exchangers. Charge of the PCM storage is investigated experimentally with solid phase SAT as initial condition. Discharge of the PCM storage with the prese...

  11. Experiments for performance enhancement of the innovative heat exchanger

    International Nuclear Information System (INIS)

    In present study, three dimension numerical analysis of Heatric PCHE is performed and compared to existing experimental data. And according to the results, the parameters to influence on thermal-hydraulic performance of PCHE have been derived and a Parametric study for the derived parameters has been performed. Based on these results, a new shape of channel in heat exchanger has been designed. And, performing three dimensional numerical analysis of a new designed heat exchanger and existing PCBE, thermal-hydraulic performance of the new designed heat exchanger has been validated numerically. And, the loop for experiments is designed for experimental investigation

  12. Heat exchanger designs for gas turbine HTGR power plant

    International Nuclear Information System (INIS)

    The performance and mechanical aspects of the recuperator and precooler designs established for a nuclear CCGT power plant in the 1200-MW(e) class are presented. These heat exchangers are designed for an integrated plant arrangement embodying three independent power conversion loops coupled to an HTGR, with one set of heat exchangers per loop. Topics discussed include heat exchanger concept evolution and selection, thermal sizing, and mechanical design. In addition to design features, fabrication and handling considerations required to accommodate the large size and weight of these units are discussed

  13. Damping of multispan heat exchanger tubes. Pt. 1: in gases

    International Nuclear Information System (INIS)

    Flow-induced vibration analyses of heat exchanger tubes require the knowledge of damping. This paper treats the question of damping on multispan heat exchanger tubes in air and gases. The different energy dissipation mechanisms that contribute to tube damping are discussed. The available experimental data are reviewed and analysed. We find that the main damping mechanism in gases is friction between tube and tube-supports. Damping is strongly related to tube-support thickness. Damping values are recommended for design purposes. This study is interesting in the nuclear industry for it often uses heat exchangers

  14. Heat exchanger and water tank arrangement for passive cooling system

    International Nuclear Information System (INIS)

    A water storage tank in the coolant water loop of a nuclear reactor contains a tubular heat exchanger. The heat exchanger has tube sheets mounted to the tank connections so that the tube sheets and tubes may be readily inspected and repaired. Preferably, the tubes extend from the tube sheets on a square pitch and then on a rectangular pitch there between. Also, the heat exchanger is supported by a frame so that the tank wall is not required to support all of its weight. 6 figures

  15. Flow-induced vibration of component cooling water heat exchangers

    International Nuclear Information System (INIS)

    This paper presents an evaluation of flow- induced vibration problems of component cooling water heat exchangers. Specifically, it describes flow-induced vibration phenomena, tests to identify the excitation mechanisms, measurement of response characteristics, analyses to predict tube response and wear, various design alterations, and modifications of the original design. Several unique features associated with the heat exchangers are demonstrated, including energy-trapping modes, existence of tube-support- plate (TSP)-inactive modes, and fluid-elastic instability of TSP-active and -inactive modes. On the basis of this evaluation, the difficulties and future research needs for the evaluation of heat exchangers are identified

  16. Miniature Joule - Thomson liquefier with sintered heat exchanger

    Science.gov (United States)

    Eugeniusz, Bodio; Maciej, Chorowski; Marta, Wilczek; Arkadiusz, Bozek

    Conventional Joule-Thomson refrigerators are made with finned, capillary tubing for the heat exchanger and a throttling valve for reducing the pressure [1]. A new kind of recuperative miniature heat-exchanger can be developed if a powder metallurgy technology is used. A high pressure capillary tube is sintered with metal powder. The grains of metal should be ball shaped or similar. In result of sintering process a good thermal contact between an outside tube surface and powder grains is achieved. The heat exchange surface is well developed and a porous sinter acts as a low pressure gas canal.

  17. Recovery of heat from wool scour effluent

    Energy Technology Data Exchange (ETDEWEB)

    Nicoll, S.R.

    1978-04-15

    The wool scouring industry uses 42% of the fuel used by the New Zealand textile industry, the fuel bill being 16% of the total scouring costs. To increase efficiency, the industry has widely adopted the Wronz scouring system which rationalizes the scouring process and increases productivity. As part of this system, heat is recovered from the effluent discharged. The economics of such heat recovery and the performance of three types of heat exchanger that have been used for this purpose are discussed. The cost of a heat exchanger can be recovered in a few months with savings in total fuel usage of up to 10%, amounting to about $7000 per annum in terms of oil costs. A spiral heat exchanger and a plate heat exchanger performed well and are recommended for this use. A multi-pass shell and tube heat exchanger was less suitable and is not recommended. The plate type is the cheapest and the most popular. The optimum size recovers 85% of the heat in the effluent at a capital cost of $9.10 per kW recovered.

  18. Turbulence and heat exchange under ice

    OpenAIRE

    Sirevaag, Anders

    2003-01-01

    Turbulent fluxes of heat and salt were measured under sea ice at four different locations around Spitsbergen. In Kongsfjorden on West Spitsbergen additional measurements of heat fluxes in the ice and in the atmosphere were done and compared in an air/sea/ice heat budget. Ocean heat flux in Kongsfjorden is about 13 W/m2 and comparison with the other heat fluxes at the ice/ocean interface shows a good agreement. From the heat budget at the ice/ocean interface, the ice growth during three subseq...

  19. Temperatures and Heat Flows in a Soil Enclosing a Slinky Horizontal Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Pavel Neuberger

    2014-02-01

    Full Text Available Temperature changes and heat flows in soils that host “slinky”-type horizontal heat exchangers are complex, but need to be understood if robust quantification of the thermal energy available to a ground-source heat pump is to be achieved. Of particular interest is the capacity of the thermal energy content of the soil to regenerate when the heat exchangers are not operating. Analysis of specific heat flows and the specific thermal energy regime within the soil, including that captured by the heat-exchangers, has been characterised by meticulous measurements. These reveal that high concentrations of antifreeze mix in the heat-transfer fluid of the heat exchanger have an adverse impact on heat flows discharged into the soil.

  20. Low Cost Polymer heat Exchangers for Condensing Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, Thomas [Brookhaven National Lab. (BNL), Upton, NY (United States); Trojanowski, Rebecca [Brookhaven National Lab. (BNL), Upton, NY (United States); Wei, George [Brookhaven National Lab. (BNL), Upton, NY (United States); Worek, Michael [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-09-30

    Work in this project sought to develop a suitable design for a low cost, corrosion resistant heat exchanger as part of a high efficiency condensing boiler. Based upon the design parameters and cost analysis several geometries and material options were explored. The project also quantified and demonstrated the durability of the selected polymer/filler composite under expected operating conditions. The core material idea included a polymer matrix with fillers for thermal conductivity improvement. While the work focused on conventional heating oil, this concept could also be applicable to natural gas, low sulfur heating oil, and biodiesel- although these are considered to be less challenging environments. An extruded polymer composite heat exchanger was designed, built, and tested during this project, demonstrating technical feasibility of this corrosion-resistant material approach. In such flue gas-to-air heat exchangers, the controlling resistance to heat transfer is in the gas-side convective layer and not in the tube material. For this reason, the lower thermal conductivity polymer composite heat exchanger can achieve overall heat transfer performance comparable to a metal heat exchanger. However, with the polymer composite, the surface temperature on the gas side will be higher, leading to a lower water vapor condensation rate.

  1. Thermal behavior of a heat exchanger module for seasonal heat storage

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon

    2012-01-01

    Experimental and theoretic investigations are carried out to study the heat transfer capacity rate of a heat exchanger module for seasonal heat storage with sodium acetate trihydrate (SAT) supercooling in a stable way. A sandwich heat storage test module has been built with the phase change material (PCM) storage box in between two plate heat exchangers. Charge of the PCM storage is investigated experimentally with solid phase SAT as initial condition. Discharge of the PCM storage with the presence of crystallization is studied experimentally. Fluid flow and heat transfer in the PCM module are theoretically investigated by Computational Fluid Dynamics (CFD) calculations. The heat transfer rates between the PCM storage and the heating fluid/cooling fluid in the plate heat exchangers are determined. The CFD calculated temperatures are compared to measured temperatures. Based on the studies, recommendations on how best to transfer heat to and from the seasonal heat storage module are given.

  2. Multiphysics Numerical Modeling of a Fin and Tube Heat Exchanger

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2015-01-01

    In the present research work, a modeling effort to predict the performance of a liquid-gas type fin and tube heat exchanger design is made. Three dimensional (3D) steady state numerical model is developed using commercial software COMSOL Multiphysics based on finite element method (FEM). For the...... purposes here, only gas flowing over the fin side is simulated assuming constant inner tube wall temperature. The study couples conjugate heat transfer mechanism with turbulent flow in order to describe the temperature and velocity profile. In addition, performance characteristics of the heat exchanger...... design in terms of heat transfer and pressure loss are determined by parameters such as overall heat transfer coefficient, Colburn j-factor, flow resistance factor, and efficiency index. The model provides useful insights necessary for optimization of heat exchanger design....

  3. Numerical Analysis of Tube-Fin Heat Exchanger using Fluent

    Directory of Open Access Journals (Sweden)

    M. V. Ghori

    2012-08-01

    Full Text Available Three-dimensional CFD simulations are carried out to investigate heat transfer and fluid flow characteristics of two-row plain Tube and Fin heat exchanger using FLUENT software. Heat transfer and pressure drop characteristics of the heat exchanger are investigated for Reynolds numbers ranging from 330 to 7000. Model geometry is created and meshed by using GAMBIT software. Fluid flow and heat transfer are simulated and results compared using both laminar and turbulent flow models k-, and SST k-omega, with steady-state solvers to calculate pressure drop, flow, and temperature fields. Model validation is carried out by comparing the simulated value friction factor f and Colburn factor j to experimental results investigate by Wang. Reasonable agreement is found between the simulations and experimental data, and the fluent software has been sufficient for simulating the flow fields in tube-fin heat exchangers.

  4. Optimization of cross flow heat exchangers for thermoelectric waste heat recovery

    International Nuclear Information System (INIS)

    Thermoelectric waste heat recovery is investigated for current thermoelectric materials with advanced heat exchangers. Numerical heat exchanger models integrated with models for Bi2Te3 thermoelectric modules are validated against experimental data from previous cross flow heat exchanger studies as well as experiments using thermoelectrics between counterflow hot water and cooling air flow channels. The models are used in optimization studies of thermoelectric waste heat recovery with air cooling in a cross flow heat exchanger. Power losses from an air fan and a fluid pump result in an optimal configuration at intermediate cooling air and hot fluid flows. Results show that heat exchangers with Bi2Te3 thermoelectrics can achieve net power densities over 40 W/l

  5. Investigation of Condensation Heat Transfer Correlation of Heat Exchanger Design in Secondary Passive Cooling System

    International Nuclear Information System (INIS)

    Recently, condensation heat exchangers have been studied for applications to the passive cooling systems of nuclear plants. To design vertical-type condensation heat exchangers in secondary passive cooling systems, TSCON (Thermal Sizing of CONdenser), a thermal sizing program for a condensation heat exchanger, was developed at KAERI (Korea Atomic Energy Research Institute). In this study, the existing condensation heat transfer correlation of TSCON was evaluated using 1,157 collected experimental data points from the heat exchanger of a secondary passive cooling system for the case of pure steam condensation. The investigation showed that the Shah correlation, published in 2009, provided the most satisfactory results for the heat transfer coefficient with a mean absolute error of 34.8%. It is suggested that the Shah correlation is appropriate for designing a condensation heat exchanger in TSCON

  6. Application of transient analysis methodology to heat exchanger performance monitoring

    International Nuclear Information System (INIS)

    A transient testing technique is developed to evaluate the thermal performance of industrial scale heat exchangers. A Galerkin-based numerical method with a choice of spectral basis elements to account for spatial temperature variations in heat exchangers is developed to solve the transient heat exchanger model equations. Testing a heat exchanger in the transient state may be the only viable alternative where conventional steady state testing procedures are impossible or infeasible. For example, this methodology is particularly suited to the determination of fouling levels in component cooling water system heat exchangers in nuclear power plants. The heat load on these so-called component coolers under steady state conditions is too small to permit meaningful testing. An adequate heat load develops immediately after a reactor shutdown when the exchanger inlet temperatures are highly time-dependent. The application of the analysis methodology is illustrated herein with reference to an in-situ transient testing carried out at a nuclear power plant. The method, however, is applicable to any transient testing application

  7. Quantum, cyclic and 'particle exchange' heat engines

    CERN Document Server

    Humphrey, T E

    2004-01-01

    We show that a range of 'non-cyclic' heat engines, including thermionic and thermoelectric devices, the three-level amplifier (thermally pumped laser), solar cells and LEDs and some Brownian heat engines all share a common thermodynamic mechanism for achieving reversibility and finite power, which is quite different from that utilized in cyclic heat engines such as the Carnot, Otto or Brayton cycles.

  8. Evaluation of fluid bed heat exchanger optimization parameters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-03-01

    Uncertainty in the relationship of specific bed material properties to gas-side heat transfer in fluidized beds has inhibited the search for optimum bed materials and has led to over-conservative assumptions in the design of fluid bed heat exchangers. An experimental program was carried out to isolate the effects of particle density, thermal conductivity, and heat capacitance upon fluid bed heat transfer. A total of 31 tests were run with 18 different bed material loads on 12 material types; particle size variations were tested on several material types. The conceptual design of a fluidized bed evaporator unit was completed for a diesel exhaust heat recovery system. The evaporator heat transfer surface area was substantially reduced while the physical dimensions of the unit increased. Despite the overall increase in unit size, the overall cost was reduced. A study of relative economics associated with bed material selection was conducted. For the fluidized bed evaporator, it was found that zircon sand was the best choice among materials tested in this program, and that the selection of bed material substantially influences the overall system costs. The optimized fluid bed heat exchanger has an estimated cost 19% below a fin augmented tubular heat exchanger; 31% below a commercial design fluid bed heat exchanger; and 50% below a conventional plain tube heat exchanger. The comparisons being made for a 9.6 x 10/sup 6/ Btu/h waste heat boiler. The fluidized bed approach potentially has other advantages such as resistance to fouling. It is recommended that a study be conducted to develop a systematic selection of bed materials for fluidized bed heat exchanger applications, based upon findings of the study reported herein.

  9. Thermal design heat sinks, thermoelectrics, heat pipes, compact heat exchangers, and solar cells

    CERN Document Server

    Lee, H S

    2010-01-01

    The proposed is written as a senior undergraduate or the first-year graduate textbook,covering modern thermal devices such as heat sinks, thermoelectric generators and coolers, heat pipes, and heat exchangers as design components in larger systems. These devices are becoming increasingly important and fundamental in thermal design across such diverse areas as microelectronic cooling, green or thermal energy conversion, and thermal control and management in space, etc. However, there is no textbook available covering this range of topics. The proposed book may be used as a capstone design cours

  10. Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-04-01

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  11. Process Heat Exchanger Options for the Advanced High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-06-01

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  12. Fabrication and Analysis of Counter Flow Helical Coil Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Swapnil Ahire

    2014-09-01

    Full Text Available Heat recovery is the capture of energy contained in fluids otherwise that would be lost from a facility. Heat sources may include heat pumps, chillers, steam condensate lines, hot flue gases from boiler, hot air associated with kitchen and laundry facilities, exhaust gases of the engines, power-generation equipment. Helical coil heat exchanger is one of the devices which are used for the heat recovery system. A heat exchanger is a device used to transfer heat between two or more fluids with different temperatures for various application including power plants, nuclear reactors, refrigeration & air condition system, automotive industries, heat recovery system, chemical processing and food industries. Common examples of heat exchangers in everyday use are air pre-heaters and conditioners, automobile radiators, condensers, evaporators, and coolers In present paper analysis of counter flow heat exchanger is done and then variations of various dimensionless numbers i.e. Reynolds Number, Nusselt’s Number and Dean’s number are studied.

  13. Damping of multispan heat exchanger tubes. Pt. 2: in liquids

    International Nuclear Information System (INIS)

    Damping information is required for flow-induced vibration analyses of heat exchanger tubes. This paper treats the question of damping of multispan heat exchanger tubes in liquids. There are three important energy dissipation mechanisms that contribute to damping in liquids. These are: viscous damping between tube and liquid, squeeze-film damping in the clearance between tube and tube-support and friction damping at the tube-support. These mechanisms are discussed and formulated in terms of heat exchanger tube parameters. The available experimental data on damping in liquids are reviewed and analysed. Semi-empirical expressions have been developed to formulate damping. These expressions are recommended for design purposes. This study is interesting in the nuclear industry for it often uses heat exchangers

  14. Phase Change Material (PCM) Heat Exchanger Development Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Project has identified two PCM HX concepts that will be designed, developed and demonstrated on-board the International Space Station (ISS):The first heat exchanger...

  15. 1-MWE heat exchangers for OTEC. Final design report

    Energy Technology Data Exchange (ETDEWEB)

    Sprouse, A.M.

    1980-06-19

    The design of a 1 MWe OTEC heat exchanger is documented, including the designs of the evaporator and associated systems, condenser, instrumentation, and materials for corrosion/erosion control and fabrication processes. (LEW)

  16. High Effectiveness Heat Exchanger for Cryogenic Refrigerators Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an innovative high performance cryogenic heat exchanger manufactured of titanium by photo-etching and diffusion bonding. This is a parallel plate design...

  17. Heat exchanger identification by using iterative fuzzy observers

    Science.gov (United States)

    Lalot, Sylvain; Guðmundsson, Oddgeir; Pálsson, Halldór; Pálsson, Ólafur Pétur

    2015-06-01

    The principle of fuzzy observers is first illustrated on a general example: the determination of the two parameters of second order systems using a step response. The set of equations describing the system are presented and it is shown that accurate results are obtained, even for a high level of noise. The heat exchanger model is then introduced. It is based on a spatial division of a counter flow heat exchanger into multiple sections. The governing equations are rewritten as a state space representation. The number of sections needed to get accurate results is determined by comparing estimated values to experimental data. Based on the mean value of the root mean squared errors, it is shown that 80 sections is an appropriate value for this heat exchanger. It is then shown that the iterative fuzzy observers can be used to determine the main parameters of the counter flow heat exchanger, i.e. the convection heat transfer coefficients, when in transient state. The final values of these parameters are <3.5 % apart from the values determined by a time consuming trial and error procedure. Finally a sensitivity study is carried out, showing that a ±1.5 % variation of the actual value of the overall heat transfer coefficient corresponds to a ±0.5 % variation of the estimated overall heat transfer coefficient. This study also shows that the fuzzy observers are equally efficient when the heat exchanger is in steady state.

  18. Heat Pipe Heat Exchangers with Double Isolation Layers for Prevention of Interpath Leakage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Cooling Technologies, Inc. (ACT), supported by Hamilton Sundstrand, proposes to develop a heat pipe heat exchanger that is low mass and provides two levels...

  19. Heat Pipe Heat Exchangers with Double Isolation Layers for Prevention of Interpath Leakage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Current manned spacecraft heat rejection systems use two heat exchangers and an intermediate fluid loop to provide isolation between the crew compartment air and...

  20. Ringshaped grid for supporting of pipes of a heat exchanger

    International Nuclear Information System (INIS)

    This heat exchanger furnishes a ring-shaped grid in which pipes can be ordered in a circular formation, as opposed to the conventional triangular ordering. In this structure the pipes are arranged in concentric circles. This means that each new row of pipes has an equal number of more pipes than the row directly inside, meaning that all the pipes in each row are equidistant from the center and form an equal surface for better heat exchange

  1. Simulation of stirred yoghurt processing in plate heat exchangers

    OpenAIRE

    Fernandes, Carla S.; Ricardo P. Dias; Nóbrega, João M.; Afonso, Isabel A.; Luis F. Melo; Maia, João M.

    2005-01-01

    In the present work, simulations of stirred yoghurt processing in a plate heat exchanger were performed using computational fluid dynamics (CFD) calculations and the results compared with experimental data, showing a very good agreement. A Herschel–Bulkley model for the viscosity and an Arrhenius-type term for the temperature dependence were used to model the thermo-rheological behaviour of yoghurt. The heat exchanger used in this study operates in a parallel arrangement, thus simplifyi...

  2. Thermal performance modeling of cross-flow heat exchangers

    CERN Document Server

    Cabezas-Gómez, Luben; Saíz-Jabardo, José Maria

    2014-01-01

    This monograph introduces a numerical computational methodology for thermal performance modeling of cross-flow heat exchangers, with applications in chemical, refrigeration and automobile industries. This methodology allows obtaining effectiveness-number of transfer units (e-NTU) data and has been used for simulating several standard and complex flow arrangements configurations of cross-flow heat exchangers. Simulated results have been validated through comparisons with results from available exact and approximate analytical solutions. Very accurate results have been obtained over wide ranges

  3. DOE/ANL/HTRI heat exchanger tube vibration data bank

    Energy Technology Data Exchange (ETDEWEB)

    Halle, H.; Chenoweth, J.M.; Wambsganss, M.W.

    1981-01-01

    This addendum to the DOE/ANL/HTRI Heat Exchanger Tube Vibration Data Bank includes 16 new case histories of field experiences. The cases include several exchangers that did not experience vibration problems and several for which acoustic vibration was reported.

  4. A fundamentally new approach to air-cooled heat exchangers.

    Energy Technology Data Exchange (ETDEWEB)

    Koplow, Jeffrey P.

    2010-01-01

    We describe breakthrough results obtained in a feasibility study of a fundamentally new architecture for air-cooled heat exchangers. A longstanding but largely unrealized opportunity in energy efficiency concerns the performance of air-cooled heat exchangers used in air conditioners, heat pumps, and refrigeration equipment. In the case of residential air conditioners, for example, the typical performance of the air cooled heat exchangers used for condensers and evaporators is at best marginal from the standpoint the of achieving maximum the possible coefficient of performance (COP). If by some means it were possible to reduce the thermal resistance of these heat exchangers to a negligible level, a typical energy savings of order 30% could be immediately realized. It has long been known that a several-fold increase in heat exchanger size, in conjunction with the use of much higher volumetric flow rates, provides a straight-forward path to this goal but is not practical from the standpoint of real world applications. The tension in the market place between the need for energy efficiency and logistical considerations such as equipment size, cost and operating noise has resulted in a compromise that is far from ideal. This is the reason that a typical residential air conditioner exhibits significant sensitivity to reductions in fan speed and/or fouling of the heat exchanger surface. The prevailing wisdom is that little can be done to improve this situation; the 'fan-plus-finned-heat-sink' heat exchanger architecture used throughout the energy sector represents an extremely mature technology for which there is little opportunity for further optimization. But the fact remains that conventional fan-plus-finned-heat-sink technology simply doesn't work that well. Their primary physical limitation to performance (i.e. low thermal resistance) is the boundary layer of motionless air that adheres to and envelops all surfaces of the heat exchanger. Within this boundary layer region, diffusive transport is the dominant mechanism for heat transfer. The resulting thermal bottleneck largely determines the thermal resistance of the heat exchanger. No one has yet devised a practical solution to the boundary layer problem. Another longstanding problem is inevitable fouling of the heat exchanger surface over time by particulate matter and other airborne contaminants. This problem is especially important in residential air conditioner systems where often little or no preventative maintenance is practiced. The heat sink fouling problem also remains unsolved. The third major problem (alluded to earlier) concerns inadequate airflow to heat exchanger resulting from restrictions on fan noise. The air-cooled heat exchanger described here solves all of the above three problems simultaneously. The 'Air Bearing Heat Exchanger' provides a several-fold reduction in boundary layer thickness, intrinsic immunity to heat sink fouling, and drastic reductions in noise. It is also very practical from the standpoint of cost, complexity, ruggedness, etc. Successful development of this technology is also expected to have far reaching impact in the IT sector from the standpointpoint of solving the 'Thermal Brick Wall' problem (which currently limits CPU clocks speeds to {approx}3 GHz), and increasing concern about the the electrical power consumption of our nation's information technology infrastructure.

  5. Computer aided heat transfer analysis in a laboratory scaled heat exchanger unit

    International Nuclear Information System (INIS)

    In this study. an explanation of a laboratory scaled heat exchanger unit and a software which is developed to analyze heat transfer. especially to use it in heat transfer courses, are represented. Analyses carried out in the software through sample values measured in the heat exchanger are: (l) Determination of heat transfer rate, logarithmic mean temperature difference and overall heat transfer coefficient; (2)Determination of convection heat transfer coefficient inside and outside the tube and the effect of fluid velocity on these; (3)Investigation of the relationship between Nusselt Number. Reynolds Number and Prandtl Number by using multiple non-linear regression analysis. Results are displayed on the screen graphically

  6. Experimental analysis of an air–water heat pump with micro-channel heat exchanger

    International Nuclear Information System (INIS)

    A multi-port extruded (MPE) aluminium flat tube air heat exchanger was compared to a round tube finned coil (FC). The MPE heat exchanger has parallel flow vertical tube configuration with headers in horizontal position and conventional folded louvred fins. The two heat exchangers were mounted on a 10 kW cooling capacity R410A packaged air heat pump. They were sized to approximately obtain the same cooling and heating capacities in chiller and heating mode, respectively. Climatic room steady state tests without frosting phenomena occurring during heat pump operation, demonstrated that the round tube and the flat tube heat exchanger performance are comparable. The MPE heat exchanger was tested with different refrigerant inlet distributor/outlet tubes configurations to investigate the effect of liquid refrigerant distribution. Cycling frosting/defrosting operations were tested with two equivalent machines placed in parallel outdoor and working at full load condition, one of the units was equipped with the MPE heat exchanger while the other mounted a standard finned coil. Penalization factors were analytically introduced to evaluate frosting associated heating energy and energy efficiency degradation. Test results indicate that both the heat pumps are penalized by frost formation but both the penalization factors are higher for the MPE-unit than the FC-unit one in the ?6 to 4 °C air dry bulb temperature range. For the two units, a roughly linear dependence of the heating energy penalization factor and of the energy efficiency factor from the difference between outdoor air and saturated air at the evaporation temperature humidity ratio can be pointed out. - Highlights: ? A multi-port aluminium flat tube heat exchanger was compared to a round tube finned one in a heat pump application. ? In steady state tests without frosting the round and the flat tube heat exchanger are comparable. ? Different inlet distributor/outlet tubes configurations were tested to investigate liquid distribution. ? Cycling frosting/defrosting operations were compared with two machines placed in parallel outdoor.

  7. Applications of two-phase flow and heat transfer in compact heat exchangers

    OpenAIRE

    Lintern, Andrew Charles

    2008-01-01

    Three applications of two-phase flow and heat transfer in plate-fin heat exchangers have been studied. A dephlegmator is a heat exchanger in which reflux condensation of a vapour mixture occurs, and plate-fln versions have importance in cryogenic gas separation processes. Numerical calculations for different binary mixtures show that the number of transfer units can be expressed as a simple function of the inlet vapour state and flow rate, heat load, and channel geometry. Th...

  8. Investigation of effect of oblique ridges on heat transfer in plate heat exchangers

    OpenAIRE

    Novosád Jan; Dvo?ák Václav

    2014-01-01

    This article deals with numerical investigation of flow in plate heat exchangers. These are counterflow heat exchangers formed by plates. These plates are shaped by the ridges to intensify heat transfer. The objective of the work is the investigation of effect of straight oblique triangular ridges for increasing of heat transfer and pressure losses. The ridges on adjacent plates intersect and thus form a channel of complex shape. The research includes various types of ridges with different fi...

  9. Liquid-metal-gas heat exchanger for HTGR type reactors

    International Nuclear Information System (INIS)

    The aim of this study is to investigate the heat transfer characteristics of a liquid metal heat exchanger (HE) for a helium-cooled high temperature reactor. A tube-type heat exchanger is considered as well as two direct exchangers: a bubble-type heat exchanger and a heat exchanger according to the spray principle. Experiments are made in order to determine the gas content of bubble-type heat exchangers, the dependence of the droplet diameter on the nozzle diameter, the falling speed of the droplets, the velocity of the liquid jet, and the temperature variation of liquid jets. The computer codes developed for HE calculation are structured so that they may be used for gas/liquid HE, too. Each type of HE that is dealt with is designed by accousting for a technical and an economic assessment. The liquid-lead jet spray is preferred to all other types because of its small space occupied and its simple design. It shall be used in near future in the HTR by the name of lead/helium HE. (GL)

  10. The fouling in the tubular heat exchanger of Algiers refinery

    Science.gov (United States)

    Harche, Rima; Mouheb, Abdelkader; Absi, Rafik

    2015-06-01

    Crude oil fouling in refinery preheat exchangers is a chronic operational problem that compromises energy recovery in these systems. Progress is hindered by the lack of quantitative knowledge of the dynamic effects of fouling on heat exchanger transfer and pressure drops. In subject of this work is an experimental determination of the thermal fouling resistance in the tubular heat exchanger of the crude oil preheats trains installed in an Algiers refinery. By measuring the inlet and outlet temperatures and mass flows of the two fluids, the overall heat transfer coefficient has been determined. Determining the overall heat transfer coefficient for the heat exchanger with clean and fouled surfaces, the fouling resistance was calculated. The results obtained from the two cells of exchangers studies, showed that the fouling resistance increased with time presented an exponential evolution in agreement with the model suggested by Kern and Seaton, with the existence of fluctuation caused by the instability of the flow rate and the impact between the particles. The bad cleaning of the heat exchangers involved the absence of the induction period and caused consequently, high values of the fouling resistance in a relatively short period of time.

  11. Development of User-Friendly Software to Design Dairy Heat Exchanger and Performance Evaluation

    OpenAIRE

    DipankarMandal

    2015-01-01

    The paper proposes a calculation algorithm and development of a software in Visual Basic(Visual Studio 2012 Express Desktop) used in heat transfer studies when different heat exchangers are involved (e.g. Helical Type Triple Tube Heat Exchanger , Plate Type Heat Exchanger).It includes the easy calculation of heat transfer coefficient and followed by the design and simulation of heat exchanger design parameter by inputting general known parameters of a heat exchanger into the devel...

  12. Forced convection heat exchange inside porous sintered metals

    International Nuclear Information System (INIS)

    Methods and results of investigating heat exchange in the process of liquid flow inside porous sintered metals have been analyzed. It has been shown that experimental data available include extremely conflicting correlations between heat transfer coefficient and Reynolds number, porosity, and relative wall thickness. Scattering of the data can attain one order of magnitude. The volume coefficient of heat transfer inside pores determined in papers does not correspond to its real value in the initial equations of the inner problem of porous cooling. Calculating and experimental method of determining the heat transfer coefficient has been developed and realized on the unit of radiation heating. More accurate experimental data on intraporous heat exchange have been obtained. It has been established that relative wall thickness does not affect the intensity of heat transfer inside pores

  13. The Experimental Study on Heat Transfer Characteristics of The External Heat Exchanger

    Science.gov (United States)

    Ji, X. Y.; Lu, X. F.; Yang, L.; Liu, H. Z.

    Using the external heat exchanger in large-scale CFB boilers can control combustion and heat transfer separately, make the adjustments of bed temperature and steam temperature convenient. The state of gas-solid two phase flow in the external heat exchanger is bubbling fluidized bed, but differs from the regular one as there is a directional flow in it. Consequently, the temperature distribution changes along the flow direction. In order to study the heat transfer characteristics of the water cooled tubes in the bubbling fluidized bed and ensure the uniformity of heat transfer in the external heat exchanger, a physical model was set up according to the similarity principle and at the geometric ratio of 1?28 to an external heat exchanger of a 300MW CFB boiler. The model was connected with an electrically heated CFB test-bed which provides the circulating particles. The influencing factors and the distribution rule of the particles' heat transfer coefficient in the external heat exchanger were assessed by measuring the temperature changes of the water in the tubes and different parts of particles flow along the flow direction. At the end, an empirical correlation of particles' heat transfer coefficient in external heat exchanger was given by modifying the Veedendery empirical correlation.

  14. Continuous cleaning of heat exchanger with recirculating fluidized bed

    International Nuclear Information System (INIS)

    Fluidized bed heat exchangers for liquids have been studied in the United States, the Netherlands, and the Federal Republic of Germany. Between 1965 and 1970, fluidized bed heat exchangers were developed in the United States as brine heaters in seawater desalination. Furthermore, their potential in the utilization of geothermal energy was tested between 1975 and 1980. In the Netherlands, fluidized bed heat exchangers have been developed since 1973 for brine heating and heat recovery in multistage flash evaporators for seawater desalination and, since about 1980, for applications in the process industry. The authors became interested in fluidized bed heat exchangers first in 1978 in connection with wastewater evaporation. The authors emphasize that the results of all these groups were in basic agreement. They can be summarized as follows: 1. The fluidized bed will in many cases maintain totally clean surfaces and neither scaling nor fouling will occur. In cases where even a fluidized bed cannot completely prevent scaling or fouling, the thickness of the layer is controlled. In these cases stable operation maintaining acceptable overall heat transfer coefficients is possible without cleaning. 2. There are always excellent heat transfer coefficients as low superficial velocities of less than ? < 0.5 m/s. 3. The pressure losses are comparable with those in normal heat exchangers since fluidized bed heat exchangers are mostly operated at low superficial velocities. 4. Feed flow may be varied between 50 and 150% or more of the design feed flow. 5. Erosion is negligible. 6. Fluidized bed particles can be manufactured from all sorts of chemically and mechanically resistant materials, such as sand, glass, ceramics, and metals

  15. Thermofluidynamic study of a sodium-sodium heat exchanger

    International Nuclear Information System (INIS)

    Sodium-sodium heat exchanges are installated in the reactor coolant system of fast breeder nuclear power plant. In the traditional engineering practice the thermal-hydraulic design of such heat exchanges is based on well-known Nu-Re-Pr correlations while three-dimensional effects are generally neglected in some applications, especially for flow regime, buoyant flow and non-uniform heat sources distributions, the 3D behaviour is an important issue in determining the heat exchanger performances. Herein a fully 3D thermal-hydraulic model of a sodium-sodium heat exchanger is presented. Each one of the 268 tubes of the bundle is modeled individually and the annular shell flow and temperature field is computed with a CFD calculation using the computer code CFX-4.1. The global heat transfer parameters of the heat exchanger are computed and compared with measured data for selected operational conditions which include the effect of local tube plugging by oxidic solid material. The comparison indicates a very good agreement between code predictions and measured data. (author)

  16. Investigation into fouling factor in compact heat exchanger

    Directory of Open Access Journals (Sweden)

    Masoud Asadi

    2013-03-01

    Full Text Available Fouling problems cannot be avoided in many heat exchanger operations, and it is necessary to introduce defensive measures to minimize fouling and the cost of cleaning. The fouling control measures used during either design or operation must be subjected to a thorough economic analysis, taking into consideration all the costs of the fouling control measures and their projected benefits in reducing costs due to fouling. Under some conditions, nearly asymptotic fouling resistances can be obtained, and this suggests a somewhat different approach to the economics. Fouling is a generic term for the deposition of foreign matter on a heat transfer surface. Deposits accumulating in the small channels of a compact heat exchanger affect both heat transfer and fluid flow. Fouling deposits constricting passages in a compact heat exchanger are likely to increase the pressure drop and therefore reduce the flow rate. Reduced flow rate may be a process constraint; it reduces efficiency and increases the associated energy use and running costs. Maintenance costs will also increase. Fouling remains the area of greatest concern for those considering the installation of compact heat exchangers. The widespread installation of compact heat exchangers has been hindered by the perception that the small passages are more strongly affected by the formation of deposits. In this paper different types of fouling and treatment are presented.

  17. Thermal behavior of a heat exchanger module for seasonal heat storage

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon; Andersen, Elsa; Chen, Ziqian; Perers, Bengt; Dannemand, Mark

    2012-01-01

    Experimental and theoretic investigations are carried out to study the heat transfer capacity rate of a heat exchanger module for seasonal heat storage with sodium acetate trihydrate (SAT) supercooling in a stable way. A sandwich heat storage test module has been built with the phase change mater...

  18. Sprinkled Heat Exchangers in Evaporation Mode

    Directory of Open Access Journals (Sweden)

    Pospisil J.

    2013-04-01

    Full Text Available The paper presents research on the heat transfer at sprinkled tube bundles situated in a test chamber at atmospheric pressure and low-pressure. Dynamic effects of physical quantities influencing the heat transfer coefficient during boiling are examined experimentally. Experimental results were achieved by means of balance measuring using thermocouple probes and by analysis of thermal diagrams created during operation periods.

  19. Fast reactor power plant design having heat pipe heat exchanger

    Science.gov (United States)

    Huebotter, Paul R. (Western Springs, IL); McLennan, George A. (Downers Grove, IL)

    1985-01-01

    The invention relates to a pool-type fission reactor power plant design having a reactor vessel containing a primary coolant (such as liquid sodium), and a steam expansion device powered by a pressurized water/steam coolant system. Heat pipe means are disposed between the primary and water coolants to complete the heat transfer therebetween. The heat pipes are vertically oriented, penetrating the reactor deck and being directly submerged in the primary coolant. A U-tube or line passes through each heat pipe, extended over most of the length of the heat pipe and having its walls spaced from but closely proximate to and generally facing the surrounding walls of the heat pipe. The water/steam coolant loop includes each U-tube and the steam expansion device. A heat transfer medium (such as mercury) fills each of the heat pipes. The thermal energy from the primary coolant is transferred to the water coolant by isothermal evaporation-condensation of the heat transfer medium between the heat pipe and U-tube walls, the heat transfer medium moving within the heat pipe primarily transversely between these walls.

  20. Capillary pumped loop body heat exchanger

    Science.gov (United States)

    Swanson, Theodore D. (Inventor); Wren, deceased, Paul (Inventor)

    1998-01-01

    A capillary pumped loop for transferring heat from one body part to another body part, the capillary pumped loop comprising a capillary evaporator for vaporizing a liquid refrigerant by absorbing heat from a warm body part, a condenser for turning a vaporized refrigerant into a liquid by transferring heat from the vaporized liquid to a cool body part, a first tube section connecting an output port of the capillary evaporator to an input of the condenser, and a second tube section connecting an output of the condenser to an input port of the capillary evaporator. A wick may be provided within the condenser. A pump may be provided between the second tube section and the input port of the capillary evaporator. Additionally, an esternal heat source or heat sink may be utilized.

  1. Assessment of ASME code examinations on regenerative, letdown and residual heat removal heat exchangers

    International Nuclear Information System (INIS)

    Inservice inspection requirements for pressure retaining welds in the regenerative, letdown, and residual heat removal heat exchangers are prescribed in Section XI Articles IWB and IWC of the ASME Boiler and Pressure Vessel Code. Accordingly, volumetric and/or surface examinations are performed on heat exchanger shell, head, nozzle-to-head, and nozzle-to-shell welds. Inspection difficulties associated with the implementation of these Code-required examinations have forced operating nuclear power plants to seek relief from the U.S. Nuclear Regulatory Commission. The nature of these relief requests are generally concerned with metallurgical, geometry, accessibility, and radiation burden. Over 60% of licensee requests to the NRC identify significant radiation exposure burden as the principle reason for relief from the ASME Code examinations on regenerative heat exchangers. For the residual heat removal heat exchangers, 90% of the relief requests are associated with geometry and accessibility concerns. Pacific Northwest National Laboratory was funded by the NRC Office of Nuclear Regulatory Research to review current practice with regard to volumetric and/or surface examinations of shell welds of letdown heat exchangers regenerative heat exchangers and residual (decay) heat removal heat exchangers Design, operating, common preventative maintenance practices, and potential degradation mechanisms are reviewed. A detailed survey of domestic and international PWR-specific operating experience was performed to identify pressure boundary failures (or lack of failures) in each heat exchanger type and NSSS design. The service data survey was based on the PIPExp- database and covers PWR plants worldwide for the period 1970-2004. Finally a risk assessment of the current ASME Code inspection requirements for residual heat removal, letdown, and regenerative heat exchangers is performed. The results are then reviewed to discuss the examinations relative to plant safety and occupational radiation exposures

  2. A Freezable Heat Exchanger for Space Suit Radiator Systems

    Science.gov (United States)

    Nabity, James A.; Mason, Georgia R.; Copeland, Robert J.; Trevino, Luis a.

    2008-01-01

    During an ExtraVehicular Activity (EVA), both the heat generated by the astronaut s metabolism and that produced by the Portable Life Support System (PLSS) must be rejected to space. The heat sources include the heat of adsorption of metabolic CO2, the heat of condensation of water, the heat removed from the body by the liquid cooling garment and the load from the electrical components. Although the sublimator hardware to reject this load weighs only 1.58 kg (3.48 lbm), an additional 3.6 kg (8 lbm) of water are loaded into the unit, most of which is sublimated and lost to space, thus becoming the single largest expendable during an eight-hour EVA. Using a radiator to reject heat from the astronaut during an EVA can reduce the amount of expendable water consumed in the sublimator. Radiators have no moving parts and are thus highly reliable. Past freezable radiators have been too heavy, but the weight can be greatly reduced by placing a small and freeze tolerant heat exchanger between the astronaut and radiator, instead of making the very large radiator freeze tolerant. Therefore, the key technological innovation to improve space suit radiator performance was the development of a lightweight and freezable heat exchanger that accommodates the variable heat load generated by the astronaut. Herein, we present the heat transfer performance of a newly designed heat exchanger that endured several freeze / thaw cycles without any apparent damage. The heat exchanger was also able to continuously turn down or turn up the heat rejection to follow the variable load.

  3. Handbook for heat exchangers and tube banks design

    CERN Document Server

    Annaratone, Donatello

    2010-01-01

    The motion of fluids is never in parallel- or counter-flow in heat exchangers and tube banks, leading to complexities in the equations for calculating their transferred heat and temperatures. This review of the topic includes 70 design and verification tables.

  4. Transfer coefficients in elliptical tubes and plate fin heat exchangers

    International Nuclear Information System (INIS)

    Mean transfer coefficients in elliptical tubes and plate fin heat exchangers were determined by application of heat and mass transfer analogy in conjunction with the naphthalene sublimation technique. The transfer coefficients are presented in a dimensionless form as functions of the Reynolds number. By using the least squares method analytical expressions for the transfer coefficients were determined with low scattering. (E.G.)

  5. Construction of Air-Cooled Heat Exchanger in Reprocessing Plant

    International Nuclear Information System (INIS)

    A large scale Air-Cooled Heat Exchanger for Rokkasho Reprocessing Plant, Aomori prefecture, has been constructed and is now under pre-operation. It is classified as 'aseismic class As', as a key facility of safety equipment from the perspective of the final cooling unit of nuclear decayed heat generated by spent fuel stored in a pool. Design criteria of heat transfer, mechanical construction, winterization and corrosion prevention for this type of exchanger are shown in comparison with an exchanger for general refinery service. The aseismic design method for the exchanger is also shown including a fan driving unit as the rotational equipment referred to in the JEAG4601-1991 Supplement. According to the pre-operation report, the maximum amplitude of vibration at a typical bearing of the fan shaft measured about 50 micro meters peak to peak. Other operational data showed good results compared to design conditions. (author)

  6. Numerical and Experimental Investigation for Heat Transfer Enhancement by Dimpled Surface Heat Exchanger in Thermoelectric Generator

    Science.gov (United States)

    Wang, Yiping; Li, Shuai; Yang, Xue; Deng, Yadong; Su, Chuqi

    2015-11-01

    For vehicle thermoelectric exhaust energy recovery, the temperature difference between the heat exchanger and the coolant has a strong influence on the electric power generation, and ribs are often employed to enhance the heat transfer of the heat exchanger. However, the introduction of ribs will result in a large unwanted pressure drop in the exhaust system which is unfavorable for the engine's efficiency. Therefore, how to enhance the heat transfer and control the pressure drop in the exhaust system is quite important for thermoelectric generators (TEG). In the current study, a symmetrical arrangement of dimpled surfaces staggered in the upper and lower surfaces of the heat exchanger was proposed to augment heat transfer rates with minimal pressure drop penalties. The turbulent flow characteristics and heat transfer performance of turbulent flow over the dimpled surface in a flat heat exchanger was investigated by numerical simulation and temperature measurements. The heat transfer capacity in terms of Nusselt number and the pressure loss in terms of Fanning friction factors of the exchanger were compared with those of the flat plate. The pressure loss and heat transfer characteristics of dimples with a depth-to-diameter ratio (h/D) at 0.2 were investigated. Finally, a quite good heat transfer performance with minimal pressure drop heat exchanger in a vehicle TEG was obtained. And based on the area-averaged surface temperature of the heat exchanger and the Seeback effect, the power generation can be improved by about 15% at Re = 25,000 compared to a heat exchanger with a flat surface.

  7. Air Circulation and Heat Exchange Under Reduced Pressures

    Science.gov (United States)

    Rygalov, V.; Wheeler, R.; Dixon, M.; Fowler, P.; Hillhouse, L.

    2010-01-01

    Heat exchange rates decrease non-linearly with reductions in atmospheric pressure. This decrease creates risk of thermal stress (elevated leaf temperatures) for plants under reduced pressures. Forced convection (fans) significantly increases heat exchange rate under almost all pressures except below 10 kPa. Plant cultivation techniques under reduced pressures will require forced convection. The cooling curve technique is a reliable means of assessing the influence of environmental variables like pressure and gravity on gas exchange of plant. These results represent the extremes of gas exchange conditions for simple systems under variable pressures. In reality, dense plant canopies will exhibit responses in between these extremes. More research is needed to understand the dependence of forced convection on atmospheric pressure. The overall thermal balance model should include latent and radiative exchange components.

  8. Renormalized anisotropic exchange for representing heat assisted magnetic recording media

    International Nuclear Information System (INIS)

    Anisotropic exchange has been incorporated in a description of magnetic recording media near the Curie temperature, as would be found during heat assisted magnetic recording. The new parameters were found using a cost function that minimized the difference between atomistic properties and those of renormalized spin blocks. Interestingly, the anisotropic exchange description at 1.5?nm discretization yields very similar switching and magnetization behavior to that found at 1.2?nm (and below) discretization for the previous isotropic exchange. This suggests that the increased accuracy of anisotropic exchange may also reduce the computational cost during simulation

  9. Heat Transfer Analysis of the Passive Residual Heat Removal Heat Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenwen; Tian, Wenxi; Su, Guanghui; Qiu, Suizheng [Jiaotong University, Shaanxi (China)

    2014-08-15

    In the present study, thermal-hydraulics characteristics of AP1000 passive residual heat removal heat exchanger (PRHR-HX) at initial operating stage were analyzed based on the porous media models. The data predicated by RELAP5 under the condition of the station blackout was employed as the inlet flow rate and temperature boundary of CFD calculation. The heat transfer from the primary side coolant to the in-containment refueling water storage tank (IRWST) side fluid was calculated in a three-dimensional geometry during iterations, and the distributed resistances were added into the C-type tube bundle regions. Three-dimensional distributions of velocity and temperature in the IRWST were calculated by the CFD code ANSYS FLUENT. The primary temperature, heat transfer coefficients of two sides and the heat transfer were obtained using the coupled heat transfer between the primary side and the IRWST side. The simulation results indicated that the water temperature rises gradually which leads to a thermal stratification phenomenon in the tank and the heat transfer capability decreases with an increase of water temperature. The present results indicated that the method containing coupled heat transfer from the primary side fluid to IRWST side fluid and porous media model is a suitable approach to study the transient thermal-hydraulics of PRHR/IRWST.

  10. Heat Transfer Analysis of the Passive Residual Heat Removal Heat Exchanger

    International Nuclear Information System (INIS)

    In the present study, thermal-hydraulics characteristics of AP1000 passive residual heat removal heat exchanger (PRHR-HX) at initial operating stage were analyzed based on the porous media models. The data predicated by RELAP5 under the condition of the station blackout was employed as the inlet flow rate and temperature boundary of CFD calculation. The heat transfer from the primary side coolant to the in-containment refueling water storage tank (IRWST) side fluid was calculated in a three-dimensional geometry during iterations, and the distributed resistances were added into the C-type tube bundle regions. Three-dimensional distributions of velocity and temperature in the IRWST were calculated by the CFD code ANSYS FLUENT. The primary temperature, heat transfer coefficients of two sides and the heat transfer were obtained using the coupled heat transfer between the primary side and the IRWST side. The simulation results indicated that the water temperature rises gradually which leads to a thermal stratification phenomenon in the tank and the heat transfer capability decreases with an increase of water temperature. The present results indicated that the method containing coupled heat transfer from the primary side fluid to IRWST side fluid and porous media model is a suitable approach to study the transient thermal-hydraulics of PRHR/IRWST

  11. Some problems of disperse medium use in heat exchangers

    International Nuclear Information System (INIS)

    The application of disperse media in heat-exchange equipment has been investigated experimentally. The authors studied heat transfer from a horizontally positioned cylinder to a layer of particles of oil-liquefied electrically produced corundum and pig iron. The coefficient of heat transfer from the cylinder to the particle layer increases 2.5 - to 3-fold as compared with pure oil, and an increase in particle diameter increases the heat-transfer coefficient. Calculations with a system with a gas suspension (a suspension of gas and solid particles) used as intermediate heat-transfer agent showed that the total surface area of its heat exchangers will be 35% larger than that of a similar system with water

  12. Hydraulic and thermal design of a gas microchannel heat exchanger

    International Nuclear Information System (INIS)

    In this paper investigations on the design of a gas flow microchannel heat exchanger are described in terms of hydrodynamic and thermal aspects. The optimal choice for thermal conductivity of the solid material is discussed by analysis of its influences on the thermal performance of a micro heat exchanger. Two numerical models are built by means of a commercial CFD code (Fluent). The simulation results provide the distribution of mass flow rate, inlet pressure and pressure loss, outlet pressure and pressure loss, subjected to various feeding pressure values. Based on the thermal and hydrodynamic analysis, a micro heat exchanger made of polymer (PEEK) is designed and manufactured for flow and heat transfer measurements in air flows. Sensors are integrated into the micro heat exchanger in order to measure the local pressure and temperature in an accurate way. Finally, combined with numerical simulation, an operating range is suggested for the present micro heat exchanger in order to guarantee uniform flow distribution and best thermal and hydraulic performances.

  13. Hydraulic and thermal design of a gas microchannel heat exchanger

    Science.gov (United States)

    Yang, Yahui; Brandner, Juergen J.; Morini, Gian Luca

    2012-05-01

    In this paper investigations on the design of a gas flow microchannel heat exchanger are described in terms of hydrodynamic and thermal aspects. The optimal choice for thermal conductivity of the solid material is discussed by analysis of its influences on the thermal performance of a micro heat exchanger. Two numerical models are built by means of a commercial CFD code (Fluent). The simulation results provide the distribution of mass flow rate, inlet pressure and pressure loss, outlet pressure and pressure loss, subjected to various feeding pressure values. Based on the thermal and hydrodynamic analysis, a micro heat exchanger made of polymer (PEEK) is designed and manufactured for flow and heat transfer measurements in air flows. Sensors are integrated into the micro heat exchanger in order to measure the local pressure and temperature in an accurate way. Finally, combined with numerical simulation, an operating range is suggested for the present micro heat exchanger in order to guarantee uniform flow distribution and best thermal and hydraulic performances.

  14. An innovative plate heat exchanger of enhanced compactness

    International Nuclear Information System (INIS)

    In the framework of CEA R&D program to develop the Advanced Sodium Technological Reactor for Industrial Demonstration (ASTRID), the present work aims to demonstrate the industrial interest of an innovative compact heat exchanger technology. In fact, one of the main innovations of the ASTRID reactor could be the use of a Brayton Gas-power conversion system, in order to avoid the energetic sodium–water interaction that might occur if a traditional Rankine cycle was used. The present work aims to study the thermal-hydraulic performance of the innovative compact heat exchanger concept. Hence, thanks to a trustful numerical model, friction factor and heat transfer correlations are obtained. Then, a global compactness comparison strategy is proposed, taking into account design constraints. Finally, it is demonstrated that the innovative heat exchanger concept is more compact then other already industrial technologies of interest, showing that is can be considered to warrant serious consideration for future ASTRID design as well as for any industrial application that needs very compact heat exchanger technologies. - Highlights: • We propose a new innovative compact heat exchanger technology. • We provide thermal-hydraulic correlations for designers. • We provide a comparison strategy with existing technologies. • We demonstrate the industrial interest of the innovative concept

  15. Pressure Drop of Hybrid Heat Exchanger for SO3 Decomposition

    International Nuclear Information System (INIS)

    A sulfur trioxide decomposer is one of the main technical challenges in the development of a nuclear hydrogen production system using SI cycle or hybrid sulfur cycle. Kim et al. developed a hybrid heat exchanger for the sulfur trioxide decomposition to withstand its severe operating conditions. The operation conditions include the high temperature over 850 .deg. C, the large pressure difference over 1 MPa, and the corrosive working fluid with the sulfuric acid gas mixture. The surface contacted with the process gas is coated with the corrosion resistant silicon carbide. Ion beam mixing technology with nitrogen ions is applied to reduce the thermal stress through the mixed interface between the coating layer and the base material. The base material of the heat exchanger is heat-resistant super alloy such as Hastelloy X. The hot gas channel plate and the process gas channel plate are joined by Park et al.'s diffusion bonding process. Kim et al. performed the sensitivity analysis of the thermo-chemical design of the hybrid-concept sulfur trioxide decomposer to determine the operation condition of the laboratory scale decomposer. The feasibility test results of the heat exchanger showed the surface enhancement effect on the corrosion-resistance in the sulfuric acid gas condition. Song et al. provided the thermal structural analysis results to install the laboratory-scale heat exchanger to maintain the structural integrity at the experimental condition. In this study, we obtained the experimental results for the pressure drop of the laboratory-scale hybrid heat exchanger

  16. Characteristics of Vertical Mantle Heat Exchangers for Solar Water Heaters

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Morrison, G.L.; Behnia, M.

    1999-01-01

    - The flow structure in vertical mantle heat exchangers was investigated using a full-scale tank designed to facilitate flow visualisation. The flow structure and velocities in the mantle were measured using a particle Image Velocimetry (PIV) system. A CFD simulation model of vertical mantle heat...... exchangers was also developed for detailed evaluation of the heat flux distribution over the mantle surface. Both the experimental and simulation results indicate that distribution of the flow around the mantle gap is governed by buoyancy driven recirculation in the mantle. The operation of the mantle was...

  17. Experimental study of heat transfer in a heat exchanger with rectangular channels

    International Nuclear Information System (INIS)

    This paper presents the results of an experimental study related to characterisation of a mini channel heat exchanger. Such heat exchanger may be used in water cooling of electronic components. The results obtained show the efficiency of this exchanger even with very low water flow rates. Indeed, in spite of the importance of the extracted heat fluxes which can reach about 50Kw/m2, the temperature of the cooled Aluminium bloc remained always lower than the tolerated threshold of 80 degree in electronic cooling. Moreover, several thermal characteristics such as equivalent thermal resistance of the exchanger, the average internal convective heat transfer coefficient and the increase in the temperature of the cooling water have been measured. The results presented have been obtained with in quinconcerectangular mini-channel heat exchanger, with a hydraulic diameter Dh = 2mm. NOMENCLATURE h D Hydraulic diameter (mm). int

  18. Heat exchangers selection, rating, and thermal design

    CERN Document Server

    Kakaç, Sadik; Pramuanjaroenkij, Anchasa

    2012-01-01

    Praise for the Bestselling Second EditionThe first edition of this work gathered in one place the essence of important information formerly scattered throughout the literature. The second edition adds the following new information: introductory material on heat transfer enhancement; an application of the Bell-Delaware method; new correlation for calculating heat transfer and friction coefficients for chevron-type plates; revision of many of the solved examples and the addition of several new ones.-MEMagazine

  19. Optimizing the Heat Exchanger Network of a Steam Reforming System

    DEFF Research Database (Denmark)

    Nielsen, Mads Pagh; Korsgaard, Anders Risum; Kær, Søren Knudsen

    Proton Exchange Membrane (PEM) based combined heat and power production systems are highly integrated energy systems. They may include a hydrogen production system and fuel cell stacks along with post combustion units optionally coupled with gas turbines. The considered system is based on a natural...... stationary numerical system model was used and process integration techniques for optimizing the heat exchanger network for the reforming unit are proposed. Objective is to minimize the system cost. Keywords: Fuel cells; Steam Reforming; Heat Exchanger Network (HEN) Synthesis; MINLP....... gas steam reformer along with gas purification reactors to generate clean hydrogen suited for a PEM stack. The temperatures in the various reactors in the fuel processing system vary from around 1000°C to the stack temperature at 80°C. Furthermore, external heating must be supplied to the endothermic...

  20. Energy and capital targets for constrained heat exchanger networks

    Directory of Open Access Journals (Sweden)

    L.C. Santos

    2000-12-01

    Full Text Available A new procedure for estimating area and capital cost targets of constrained heat exchanger networks is presented. The method allows for match constrained networks and exchangers with more than one tube pass. The procedure is based on modelling the problem as a non-linear formulation where the forbidden exchanger matches are included as constraints and the temperature difference correction due to multipass exchangers is included in the model. The difficulty of converging to a solution due to the additional non-linear constraints imposed by the multipass exchangers required the use of a two-level approach: at the inner level, the area targets for simple pass exchangers are obtained, and at the outer level the temperature difference required for multipass exchangers are computed and fed back to the inner level. The procedure is repeated until an appropriate tolerance between two iterations was achieved. A comparison between the estimated exchanger areas and costs estimated by the new procedure and the area and costs obtained from the final heat exchanger design shows a very good agreement.

  1. Wind sensitivity of the inter-ocean heat exchange

    OpenAIRE

    Corell, Hanna; Nilsson, Johan; Döös, Kristofer; Broström, Göran

    2009-01-01

    An idealised two-basin model is used to investigate the impact of the wind field on the heat exchange between the ocean basins. The scalar potential of the divergent component of the horizontal heat flux is computed, which gives a 'coarse-grained' image of the surface heat flux that captures the large-scale structure of the horizontal heat transport. Further the non-divergent component is examined, as well as the meridional heat transport and the temperature–latitude overturning stream functi...

  2. Compact interior heat exchangers for CO{sub 2} mobile heat pumping systems

    Energy Technology Data Exchange (ETDEWEB)

    Hafner, Armin

    2003-07-01

    The natural refrigerant carbon dioxide (CO{sub 2}) offers new possibilities for design of flexible, efficient and environmentally safe mobile heat pumping systems. As high-efficient car engines with less waste heat are developed, extra heating of the passenger compartment is needed in the cold season. A reversible transcritical CO{sub 2} system with gliding temperature heat rejection can give high air delivery temperature which results in rapid heating of the passenger compartment and rapid defogging or defrosting of windows. When operated in cooling mode, the efficiency of transcritical CO{sub 2} systems is higher compared to common (HFC) air conditioning systems, at most dominant operating conditions. Several issues were identified for the design of compact interior heat exchangers for automotive reversible CO{sub 2} heat pumping systems. Among theses issues are: (1) Refrigerant flow distribution, (2) Heat exchanger fluid flow circuiting, (3) Air temperature uniformity downstream of the heat exchanger, (4) Minimization of temperature approach, (5) Windshield flash fogging due to retained water inside the heat exchanger, (6) Internal beat conduction in heating mode operation, and (7) Refrigerant side pressure drop In order to provide a basis for understanding these issues, the author developed a calculation model and set up a test facility and investigated different prototype heat exchangers experimentally.

  3. Laminar fluid flow and heat transfer in a fin-tube heat exchanger with vortex generators

    Energy Technology Data Exchange (ETDEWEB)

    Yanagihara, J.I.; Rodriques, R. Jr. [Polytechnic School of Univ. of Sao Paolo, Sao Paolo (Brazil). Dept. of Mechanical Engineering

    1996-12-31

    Development of heat transfer enhancement techniques for fin-tube heat exchangers has great importance in industry. In recent years, heat transfer augmentation by vortex generators has been considered for use in plate fin-tube heat exchangers. The present work describes a numerical investigation about the influence of delta winglet pairs of vortex generators on the flow structure and heat transfer of a plate fin-tube channel. The Navier-Stokes and Energy equations are solved by the finite volume method using a boundary-fitted coordinate system. The influence of vortex generators parameters such as position, angle of attack and aspect ratio were investigated. Local and global influences of vortex generators in heat transfer and flow losses were analyzed by comparison with a model using smooth fin. The results indicate great advantages of this type of geometry for application in plate fin-tube heat exchangers, in terms of large heat transfer enhancement and small pressure loss penalty. (author)

  4. Plastic heat exchangers: a state-of-the-art review

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D; Holtz, R E; Koopman, R N; Marciniak, T J; MacFarlane, D R

    1979-07-01

    Significant increases in energy utilization efficiency can be achieved through the recovery of low-temperature rejected heat. This energy conserving possibility provides incentive for the development of heat exchangers which could be employed in applications where conventional units cannot be used. Some unique anticorrosion and nonstick characteristics of plastics make this material very attractive for heat recovery where condensation, especially sulfuric acid, and fouling occur. Some of the unique characteristics of plastics led to the commercial success of DuPont's heat exchangers utilizing polytetrafluoroethylene (trade name Teflon) tubes. Attributes which were exploited in this application were the extreme chemical inertness of the material and its flexibility, which enabled utilization in odd-shaped spaces. The wide variety of polymeric materials available ensures chemical inertness for almost any application. Lower cost, compoundability with fillers to improve thermal/mechanical properties, and versatile fabrication methods are incentives for many uses. Also, since many plastics resist corrosion, they can be employed in lower temperature applications (< 436 K), where condensation can occur and metal units have been unable to function. It is clear that if application and design can be merged to produce a cost-effective alternate to present methods of handling low-temperature rejected heat, then there is significant incentive for plastic heat exchangers, to replace traditional metallic heat exchangers or to be used in services where metals are totally unsuited.

  5. Heat recovery from Diesel exhausts by means of a fluidized bed heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Carlomagno, G.M.; Festa, R.; Massimilla, L.

    1983-01-01

    A fluidized bed heat exchanger, equipped with a specially designed manifold gas distributor, is conveniently used to recover heat from exhausts of a 60 kW Diesel engine. The sensitivity of the bed to tube heat transfer coefficient to soot fouling and the sensitivity of the exchanger efficiency to variations of such coefficients are analyzed. Procedures for in-operation tube defouling are described.

  6. Compact heat exchanger technologies for the HTRs recuperator application

    International Nuclear Information System (INIS)

    Modern HTR nuclear power plants which are now under development (projects GT-MHR, PBMR) are based on the direct cycle concept. This concept leads to a more important efficiency compared to the steam cycle but requires the use of high performance components such as an helium/helium heat exchanger called recuperator to guarantee the cycle efficiency. Using this concept, a net plant efficiency of around 50% can be achieved in the case of an electricity generating plant. As geometric constraints are particularly important for such a gas reactor to limit the size of the primary vessels, compact heat exchangers operating at high pressure and high temperature are attractive potential solutions for the recuperator application. In this frame, Framatome and CEA have reviewed the various technologies of compact heat exchangers used in industry. The first part of the paper will give a short description of the heat exchangers technologies and their ranges of application. In a second part, a selection of potential compact heat exchangers technologies are proposed for the recuperator application. This selection will be based upon their capabilities to cope with the operating conditions parameters (pressure, temperature, flow rate) and with other parameters such as fouling, corrosion, compactness, weight, maintenance and reliability. (author)

  7. Experimental investigation of water sprayed finned heat exchanger tube bundles

    International Nuclear Information System (INIS)

    Experimental investigations have been made to study the performance of two finned tube-bundle heat exchangers (FORGO type) when wetted by water sprays. The heat exchangers are designed to cool water in a dry cooling tower. The test-elements had a frontal area of 1 m2. The water sprays were created by 20 nozzles, 200 mm in front of the heat exchangers. Air velocities at the inlet of the coolers were in the range 0,8 m/s to 12 m/s and initial temperature differences ITD reached 45 degrees C. The test facility was designed to determine the combined latent and sensible heat fluxes in the wetted heat exchanger, the airside pressure drop and the air humidity and temperature at the exchanger inlet and outlet, and to measure the weight of the water wetting the cooler's surface. The sprayed test elements were investigated in different positions, but most of the experiments were carried out in the position with the fins horizontal

  8. Unique double-pipe internal heat exchanger for MAC

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, H.; Gyoeroeg, T.; Huenemoerder, W. [DENSO Automotive Deutschland GmbH (Germany)

    2007-07-01

    In automotive air conditioning, balancing comfort and fuel efficiency is very important. Vehicle cooling performance improvements during initial cool down has reached a limit in recent years, especially in very hot regions. We have addressed this issue by developing a unique double-pipe internal heat exchanger. In the main discourse, we first clarify the concept of the internal heat exchanger system (IHE) using the temperature difference between the high and low pressure pipes in the refrigeration cycle, and propose the application of an efficient internal heat exchanger. This unique double-pipe internal heat exchanger can easily be manufactured by inserting the inner pipe into the outer pipe and by fixing the pipes at both ends. The length of the IHE is 400mm(for example). This double-pipe internal heat exchanger can increase cooling performance by 5-12% at the equivalent power consumption levels in the same space as a conventional front air conditioner system. The result is an increase in the coefficient of performance (COP) by 10-15% at equivalent cooling performance. (orig.)

  9. Computer simulation of cored brick regenerative heat exchangers

    International Nuclear Information System (INIS)

    A computer model has been developed to simulate the thermal response of a cored brick regenerative heat exchanger to be used in magnetohydrodynamic energy conversion processes. The model uses a set of finite-difference equations to simulate the heat exchange core between gas and ceramic the equations calculate the temperature variation of the gas and ceramic along the axis of the heat exchange. The insulation and steel shell are thermally coupled to the core by a second set of finite-difference equations. The physical properties of the core, insulation, and gas are curvefit as functions of temperature, and the vertical gaps between insulator layers, causing thermal resistance in the heat exchange, are also represented. The time, burner operation, and intermediate cooldown cycles necessary to reach cyclic, steady-state operating conditions from room temperature are determined during the start-up simulation the response of the insulation to changes in core temperature was studied during the steady-state simulation the time required to reduce the core and insulation temperature to safe operating levels was determined during the shut-down simulation. It was concluded that at least 16 hours are necessary for the heat exchanger to reach cyclic, steady-state conditions, and that during a power failure, a back-up power source will be needed for at least 27 hours to insure the safety of the facility

  10. Intensification of heat exchange processes in cryogenic plants and systems

    International Nuclear Information System (INIS)

    This paper reports on heat exchange processes and apparatus that are responsible for efficient and reliable performance of cryogenic equipment. Certain institutes and companies in USSR have performed extensive investigations, engineering and test works to intensify heat exchange processes and to improve designs of heat exchange apparatus. Presently, the cryogenic platts and systems are furnished with the apparatus wherein use is made of effective heat exchange components of various designs. Thus, when manufacturing coiled condenser-evaporators, liquid subcoolers for large air separation plants, and coolers for cryogenic product storage systems, use is made of aluminum tubes with external transverse finning of various fin heights. To manufacture the coolers and gasificators for various cryogenic product, tubes with external capillary-porous coating, as well as tubes with internal longitudinal fining using notched aluminum packing find wide application. Plate-fin aluminum heat exchangers with various packings are used in cooling units, condenser-evaporators and cryogenic liquid subcoolers. Copper tubes with wire-type external transversal finning are employed for helium liquefier and refrigerator apparatus

  11. Prediction of Heat Removal Capacity of Horizontal Condensation Heat Exchanger submerged in Pool

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Seong-Su; Hong, Soon-Joon [FNC Tech., Yongin (Korea, Republic of); Cho, Hyoung-Kyu [Seoul National University, Seoul (Korea, Republic of); Park, Goon-Cherl [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2014-10-15

    As representative passive safety systems, there are the passive containment cooling system (PCCS) of ESBWR, the emergency condenser system (ECS) of the SWR-1000, the passive auxiliary feed-water system (PAFS) of the APR+ and etc. During the nuclear power plant accidents, these passive safety systems can cool the nuclear system effectively via the heat transfer through the steam condensation, and then mitigate the accidents. For the optimum design and the safety analysis of the passive safety system, it is essential to predict the heat removal capacity of the heat exchanger well. The heat removal capacity of the horizontal condensation heat exchanger submerged in a pool is determined by a combination of a horizontal in-tube condensation heat transfer and a boiling heat transfer on the horizontal tube. Since most correlations proposed in the previous nuclear engineering field were developed for the vertical tube, there is a certain limit to apply these correlations to the horizontal tube. Therefore, this study developed the heat transfer model for the horizontal Ushaped condensation heat exchanger submerged in a pool to predict well the horizontal in-tube condensation heat transfer, the boiling heat transfer on the horizontal tube and the overall heat removal capacity of the heat exchanger using the best-estimate system analysis code, MARS.

  12. Effect of nanoparticles on heat transfer in mini double-pipe heat exchangers in turbulent flow

    Science.gov (United States)

    Aghayari, Reza; Maddah, Heydar; Ashori, Fatemeh; Hakiminejad, Afshin; Aghili, Mehdi

    2015-03-01

    In this work, heat transfer of a fluid containing nanoparticles of aluminum oxide with the water volume fraction (0.1-0.3) percent has been reported. Heat transfer of the fluid containing nano water aluminum oxide with a diameter of about 20 nm in a horizontal double pipe counter flow heat exchanger under turbulent flow conditions was studied. The results showed that the heat transfer of nanofluid in comparison with the heat transfer of fluid is slightly higher than 12 percent.

  13. 40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 13 2010-07-01 2010-07-01 false Requirements for Heat Exchange Systems... Manufacturing Pt. 63, Subpt. HHHHH, Table 6 Table 6 to Subpart HHHHH of Part 63—Requirements for Heat Exchange... your heat exchange systems. For each . . . You must . . . Heat exchange system, as defined in §...

  14. 40 CFR 63.1083 - Does this subpart apply to my heat exchange system?

    Science.gov (United States)

    2010-07-01

    ... CATEGORIES (CONTINUED) National Emission Standards for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1083 Does this subpart apply to my heat exchange system? The provisions of this subpart apply to your heat exchange system if you...

  15. Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    R.E. Mizia; D.E. Clark; M.V. Glazoff; T.E. Lister; T.L. Trowbridge

    2011-04-01

    The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. The intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding.

  16. Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

    International Nuclear Information System (INIS)

    The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. The intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding.

  17. Liquid Salt Heat Exchanger Technology for VHTR Based Applications

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark; Sridhara, Kumar; Allen, Todd; Peterson, Per

    2012-10-11

    The objective of this research is to evaluate performance of liquid salt fluids for use as a heat carrier for transferring high-temperature process heat from the very high-temperature reactor (VHTR) to chemical process plants. Currently, helium is being considered as the heat transfer fluid; however, the tube size requirements and the power associated with pumping helium may not be economical. Recent work on liquid salts has shown tremendous potential to transport high-temperature heat efficiently at low pressures over long distances. This project has two broad objectives: To investigate the compatibility of Incoloy 617 and coated and uncoated SiC ceramic composite with MgCl2-KCl molten salt to determine component lifetimes and aid in the design of heat exchangers and piping; and, To conduct the necessary research on the development of metallic and ceramic heat exchangers, which are needed for both the helium-to-salt side and salt-to-process side, with the goal of making these heat exchangers technologically viable. The research will consist of three separate tasks. The first task deals with material compatibility issues with liquid salt and the development of techniques for on-line measurement of corrosion products, which can be used to measure material loss in heat exchangers. Researchers will examine static corrosion of candidate materials in specific high-temperature heat transfer salt systems and develop an in situ electrochemical probe to measure metallic species concentrations dissolved in the liquid salt. The second task deals with the design of both the intermediate and process side heat exchanger systems. Researchers will optimize heat exchanger design and study issues related to corrosion, fabrication, and thermal stresses using commercial and in-house codes. The third task focuses integral testing of flowing liquid salts in a heat transfer/materials loop to determine potential issues of using the salts and to capture realistic behavior of the salts in a small scale prototype system. This includes investigations of plugging issues, heat transfer, pressure drop, and the corrosion and erosion of materials in the flowing system.

  18. Experimental investigation of a reticulated porous alumina heat exchanger for high temperature gas heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, A; Chandran, RB; Davidson, JH

    2015-01-22

    The present study presents an experimental study of a prototype counter-flow heat exchanger designed to recover sensible heat from inert and reactive gases flowing through a high temperature solar reactor for splitting CO2. The tube-in-tube heat exchanger is comprised of two concentric alumina tubes, each filled with reticulated porous alumina with a nominal porosity of 80% and pore density of 5 pores per inch (ppi). The RPC provides high heat transfer surface area per unit volume (917 m(-1)) with low pressure drop. Measurements include the permeability, inertial coefficient, overall heat transfer coefficient, effectiveness and pressure drop. For laminar flow and an inlet gas temperature of 1240 K, the overall heat transfer coefficients are 36-41 W m(-2) K-1. The measured performance is in good agreement with a prior CFD model of the heat exchanger. (C) 2014 Elsevier Ltd. All rights reserved.

  19. A Cell Model to Describe and Optimize Heat and Mass Transfer in Contact Heat Exchangers

    OpenAIRE

    Piotr Yakimychev; Nickolay Yelin; Vadim Mizonov

    2011-01-01

    A cell model to describe and optimize heat and mass transfer in contact heat exchangers for utilization of exhaust gases heat is proposed. The model is based on the theory of Markov chains and allows calculating heat and mass transfer at local moving force of the processes in each cell. The total process is presented as two parallel chains of cells (one for water flow and one for gas flow). The corresponding cells of the chains can exchange heat and mass, and water and gas can travel along th...

  20. Air-side particulate fouling of microchannel heat exchangers: Experimental comparison of air-side pressure drop and heat transfer with plate-fin heat exchanger

    OpenAIRE

    Bell, Ian; Groll, Eckhard

    2011-01-01

    In this study, the air-side pressure drop and heat transfer performance of plate-fin and microchannel coils were tested under clean and fouled conditions. The heat exchangers were tested with two different types of dust, ASHRAE Standard Dust and Arizona Road Test Dust. The ASHRAE Standard Dust was found to have a very significant impact on the pressure drop of the microchannel heat exchanger, increasing the air-side pressure drop of the microchannel heat exchanger over 200% for a dust injec...

  1. Materials, Turbomachinery and Heat Exchangers for Supercritical CO2 Systems

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark; Nellis, Greg; Corradini, Michael

    2012-10-19

    The objective of this project is to produce the necessary data to evaluate the performance of the supercritical carbon dioxide cycle. The activities include a study of materials compatibility of various alloys at high temperatures, the heat transfer and pressure drop in compact heat exchanger units, and turbomachinery issues, primarily leakage rates through dynamic seals. This experimental work will serve as a test bed for model development and design calculations, and will help define further tests necessary to develop high-efficiency power conversion cycles for use on a variety of reactor designs, including the sodium fast reactor (SFR) and very high-temperature gas reactor (VHTR). The research will be broken into three separate tasks. The first task deals with the analysis of materials related to the high-temperature S-CO{sub 2} Brayton cycle. The most taxing materials issues with regard to the cycle are associated with the high temperatures in the reactor side heat exchanger and in the high-temperature turbine. The system could experience pressures as high as 20MPa and temperatures as high as 650°C. The second task deals with optimization of the heat exchangers required by the S-CO{sub 2} cycle; the S-CO{sub 2} flow passages in these heat exchangers are required whether the cycle is coupled with a VHTR or an SFR. At least three heat exchangers will be required: the pre-cooler before compression, the recuperator, and the heat exchanger that interfaces with the reactor coolant. Each of these heat exchangers is unique and must be optimized separately. The most challenging heat exchanger is likely the pre-cooler, as there is only about a 40°C temperature change but it operates close to the CO{sub 2} critical point, therefore inducing substantial changes in properties. The proposed research will focus on this most challenging component. The third task examines seal leakage through various dynamic seal designs under the conditions expected in the S-CO{sub 2} cycle, including supercritical, choked, and two-phase flow conditions.

  2. Applications of artificial neural networks for thermal analysis of heat exchangers - A review

    International Nuclear Information System (INIS)

    Artificial neural networks (ANN) have been widely used for thermal analysis of heat exchangers during the last two decades. In this paper, the applications of ANN for thermal analysis of heat exchangers are reviewed. The reported investigations on thermal analysis of heat exchangers are categorized into four major groups, namely (i) modeling of heat exchangers, (ii) estimation of heat exchanger parameters, (iii) estimation of phase change characteristics in heat exchangers and (iv) control of heat exchangers. Most of the papers related to the applications of ANN for thermal analysis of heat exchangers are discussed. The limitations of ANN for thermal analysis of heat exchangers and its further research needs in this field are highlighted. ANN is gaining popularity as a tool, which can be successfully used for the thermal analysis of heat exchangers with acceptable accuracy. (authors)

  3. Potential polymer concrete heat exchanger tubes for corrosive environments

    Energy Technology Data Exchange (ETDEWEB)

    Fontana, J.J.; Reams, W.; Cheng, H.C.

    1986-11-01

    It has long been known that carbon steel exposed to some geothermal brines is aggressively attacked, and large corrosion allowances must be made in the design of piping used in such environments. In addition, scaling of the pipes reduces the flow through within a short period of time. Several high temperature polymer concretes have been developed which can be used as non-corrosive liner materials. In addition, polymer concretes with high thermal conductivities have been developed which may be used as heat exchanger tubes for geothermal brines. Studies have indicated that polymer concretes will not scale as rapidly as carbon steel does, thus making them attractive alternatives for heat exchanger tubes. Thin walled, thermally conductive polymer concrete tubes have been made that can withstand pressures >4.1 MPa at 150/sup 0/C without leaking. Continuing studies are being made to characterize these materials and evaluate them for heat exchanger applications.

  4. Multi-way tube-type heat exchanger

    International Nuclear Information System (INIS)

    In the cylindrical casing, U shaped heat exchange tubes are firmly anchored in the tube plate. The inner space of the casing is divided with a transverse plate normal to the plane of the tubes and with at least one partition wall parallel to the tube plane. The casing is provided with a cover whose inner space is divided with a partition and with at least one cross wall into an inlet area, an outlet area and a turning chamber. The inlet area of the cover adjoins the outlet channel of the casing and the outlet area of the cover adjoins the inlet channel of the casing via the tube plate. This configuration of the heat exchanger makes it possible to maintain the counter current flow throughout the entire heat exchange area. (E.S.)

  5. Flow-induced vibration of component cooling water heat exchangers

    International Nuclear Information System (INIS)

    This paper presents an evaluation of flow-induced vibration problems of component cooling water heat exchangers in one of Taipower's nuclear power stations. Specifically, it describes flow-induced vibration phenomena, tests to identify the excitation mechanisms, measurement of response characteristics, analyses to predict tube response and wear, various design alterations, and modifications of the original design. Several unique features associated with the heat exchangers are demonstrated, including energy-trapping modes, existence of tube-support-plate (TSP)-inactive modes, and fluidelastic instability of TSP-active and -inactive modes. On the basis of this evaluation, the difficulties and future research needs for the evaluation of heat exchangers are identified. 11 refs., 19 figs., 3 tabs

  6. Preliminary results of statistical dynamic experiments on a heat exchanger

    International Nuclear Information System (INIS)

    The inherent noise signals present in a heat exchanger have been recorded and analysed in order to determine some of the statistical dynamic characteristics of the heat exchanger. These preliminary results show that the primary side temperature frequency response may be determined by analysing the inherent noise. The secondary side temperature frequency response and cross coupled temperature frequency responses between primary and secondary are poorly determined because of the presence of a non-stationary noise source in the secondary circuit of this heat exchanger. This may be overcome by correlating the dependent variables with an externally applied noise signal. Some preliminary experiments with an externally applied random telegraph type of signal are reported. (author)

  7. Mill Scale Corrosion and Prevention in Carbon Steel Heat Exchanger

    Science.gov (United States)

    Sharma, Pankaj; Roy, Himadri

    2015-10-01

    The cause of material degradation of an ASTM A-124 grade carbon steel tube belonging to a heat exchanger has been investigated. Visual examination, followed by an in-depth microstructural characterization using optical microscopy, energy dispersive X-ray, and scanning electron microscopy, was carried out for understanding the primary cause of material degradation. Based on the results of an extensive examination as well as the background information provided on the heat exchanger, it was determined that the steel tubes were predominantly damaged by the mechanism of crevice corrosion facilitated by the presence of mill scale. It is concluded that the heat exchanger tubes were not properly investigated for defects after their fabrication. Based on the situation, the proper cleaning method was selected for preventing further corrosion in the system. A chemical cleaning process was designed using acid pickling along with an inhibitor and a surfactant.

  8. Heat exchangers for automotive gas turbine power plants

    International Nuclear Information System (INIS)

    Automotive gas turbine power plants are now in the final stages of development for quantity manufacture. A crucial factor in this development is the regenerative heat exchanger. The relative merits of the rotary regenerative and static recuperative heat exchanger are compared. Thermal efficiency and initial cost are two vital issues involved in the design of small gas turbines for the commercial establishment of gas turbine vehicles. The selection of a material for the rotaty regenerator is essentially related to resolving the two vital issues of future small gas turbines and is, therefore, analysed. The account of the pioneering work involved in engineering the glass ceramic and other non-metal regenerators includes a complete failure analysis based on running experience with over 200 ceramic regenerators. The problems of sealing, supporting and manufacturing the ceramic regenerator are discussed and future practical designs are outlined. Heat exchange theory applied to small gas turbines is also reviewed

  9. Heat transfer of high thermal energy storage with heat exchanger for solar trough power plant

    International Nuclear Information System (INIS)

    High temperature thermal energy storage was studied by a lab-scale cylindrical storage tank experiment. A heat exchanger of thermal energy storage is used for separating two fluids, storage medium, and heat transfer fluid (HTF). There are two types of pipe in the heat exchanger, a vertical straight pipe and a helical coiled pipe. The experimental results were validated with the created mathematical model of nonsteady state heat exchanger. The highest storage efficiency is 0.631 at the HTF flow rate of 0.1 kg/s in a helical coiled pipe heat exchanger. The HTF and storage medium temperatures were measured for validating the model at various HTF flow rates. The agreement between model and experiment was presented with the error below 10%. This model is able to calculate the storage temperature of solar thermal power plants that performs in the liquid temperature range of selected HTF and storage medium

  10. Diffusion Welding of Compact Heat Exchangers for Nuclear Applications

    Energy Technology Data Exchange (ETDEWEB)

    Denis Clark; Ron Mizia; Dr. Michael V. Glazoff; Mr. Michael W. Patterson

    2012-06-01

    The next-­-generation nuclear plant (NGNP) is designed to be a flexible source of energy, producing various mixes of electrical energy and process heat (for example, for hydrogen generation) on demand. Compact heat exchangers provide an attractive way to move energy from the helium primary reactor coolant to process heat uses. For process heat efficiency, reactor outlet temperatures of 750-­-900°C are desirable. There are minor but deleterious components in the primary coolant; the number of alloys that can handle this environment is small. The present work concentrates on Alloys 800H and 617.

  11. Comparative design evaluation of plate fin heat exchanger and coiled finned tube heat exchanger for helium liquefier in the temperature range of 300-80 K

    International Nuclear Information System (INIS)

    Present indigenous helium liquefaction system at RRCAT uses the cross-counter flow coiled-finned tube heat exchangers developed completely from Indian resources. These coiled-finned tube heat exchangers are mainly suitable up to medium capacity helium liquefiers. For large capacity helium liquefier, plate fin heat exchangers are more suitable options. This paper presents the comparative evaluation of the design of both types of heat exchangers in the temperature range of 300-80 K for helium liquefier. (author)

  12. Prefabricated heat-exchanging fireplace. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Schleper, M.A.

    1981-06-15

    A heat-exchanging fireplace was installed in a 2000 square foot home and the standard air distribution equipment was ducted directly to the forced-air heating system of the home. The standard air distribution equipment for the fireplace included two squirrel-cage blowers which were connected to a thermostat, allowing a choice of temperature ranges; and a snap disc thermostat was used to disconnect the blowers in order to avoid blowing cold air after the fire died out. Arranged in this manner, one is able to set the regular home thermostat a few degrees lower than the fireplace thermostat, and this will allow the regular heating system to turn on after the fire has gone out in the fireplace. Energy consumption in both the fireplace and the conventional heating system was monitored throughout a heating season and then compared with past heating seasons when only a conventional heating system was used.

  13. Development of User-Friendly Software to Design Dairy Heat Exchanger and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    DipankarMandal

    2015-02-01

    Full Text Available The paper proposes a calculation algorithm and development of a software in Visual Basic(Visual Studio 2012 Express Desktop used in heat transfer studies when different heat exchangers are involved (e.g. Helical Type Triple Tube Heat Exchanger , Plate Type Heat Exchanger.It includes the easy calculation of heat transfer coefficient and followed by the design and simulation of heat exchanger design parameter by inputting general known parameters of a heat exchanger into the developed software—-?DAIRY –HE ?. A parametric study is conducted using the software interface to determine the length of tubes or dimensions of heat exchanger.

  14. Exergy optimization in a steady moving bed heat exchanger.

    Science.gov (United States)

    Soria-Verdugo, A; Almendros-Ibáñez, J A; Ruiz-Rivas, U; Santana, D

    2009-04-01

    This work provides an energy and exergy optimization analysis of a moving bed heat exchanger (MBHE). The exchanger is studied as a cross-flow heat exchanger where one of the phases is a moving granular medium. The optimal MBHE dimensions and the optimal particle diameter are obtained for a range of incoming fluid flow rates. The analyses are carried out over operation data of the exchanger obtained in two ways: a numerical simulation of the steady-state problem and an analytical solution of the simplified equations, neglecting the conduction terms. The numerical simulation considers, for the solid, the convection heat transfer to the fluid and the diffusion term in both directions, and for the fluid only the convection heat transfer to the solid. The results are compared with a well-known analytical solution (neglecting conduction effects) for the temperature distribution in the exchanger. Next, the analytical solution is used to derive an expression for the exergy destruction. The optimal length of the MBHE depends mainly on the flow rate and does not depend on particle diameter unless they become very small (thus increasing sharply the pressure drop). The exergy optimal length is always smaller than the thermal one, although the difference is itself small. PMID:19426351

  15. Modeling and Performance Analysis of Alternative Heat Exchangers for Heavy Vehicles

    OpenAIRE

    Lin, Wamei

    2014-01-01

    Cross flow heat exchangers made from aluminum are common as radiators in vehicles. However, due to the increasing power requirement and the limited available space in vehicles, it is extremely difficult to increase the size of heat exchangers (HEXs) placed in the front of vehicles. Placing the heat exchanger on the roof or at the underbody of vehicles might offer opportunity to increase the size of the heat exchangers. A new configuration of heat exchangers has to be developed to accommodate ...

  16. Performance of a Thermoelectric Device with Integrated Heat Exchangers

    Science.gov (United States)

    Barry, Matthew M.; Agbim, Kenechi A.; Chyu, Minking K.

    2015-06-01

    Thermoelectric devices (TEDs) convert heat directly into electrical energy, making them well suited for waste heat recovery applications. An integrated thermoelectric device (iTED) is a restructured TED that allows more heat to enter the p-n junctions, thus producing a greater power output . An iTED has heat exchangers incorporated into the hot-side interconnectors with flow channels directing the working fluid through the heat exchangers. The iTED was constructed of p- and n-type bismuth-telluride semiconductors and copper interconnectors and rectangular heat exchangers. The performance of the iTED in terms of , produced voltage and current , heat input and conversion efficiency for various flow rates (), inlet temperatures (C) ) and load resistances () with a constant cold-side temperature ( = 0C) was conducted experimentally. An increase in had a greater effect on the performance than did an increase in . A 3-fold increase in resulted in a 3.2-, 3.1-, 9.7-, 3.5- and 2.8-fold increase in and respectively. For a constant of 50C, a 3-fold increase in from 3300 to 9920 resulted in 1.6-, 1.6-, 2.6-, 1.5- and 1.9-fold increases in , , , and respectively.

  17. Multi-objective optimization of organic Rankine cycles for waste heat recovery: Application in an offshore platform

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Nguyen, Tuong-Van; Larsen, Ulrik; Haglind, Fredrik; Elmegaard, Brian

    2013-01-01

    This paper aims at finding the optimal design of MW-size organic Rankine cycles by employing the multi-objective optimization with the genetic algorithm as the optimizer. We consider three objective functions: thermal efficiency, total volume of the system and net present value. The optimization...... variables are the working fluid, the turbine inlet pressure and temperature, the condensing temperature, the pinch points and the fluid velocities in the heat exchangers. The optimization process also includes the complete design of the shell and tube heat exchangers utilized in the organic Rankine cycle....... The methodology is applied to recover the waste heat from the SGT-500 gas turbine installed on the Draugen off-shore oil and gas platform in the North Sea. Results suggest two optimal working fluids, i.e. acetone and cyclopentane. Thermal efficiency and net present value are higher for cyclopentane...

  18. Internal dust recirculation system for a fluidized bed heat exchanger

    Science.gov (United States)

    Gamble, Robert L. (Wayne, NJ); Garcia-Mallol, Juan A. (Morristown, NJ)

    1981-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided in a heat exchange relation to the bed and includes a steam drum disposed adjacent the bed and a tube bank extending between the steam drum and a water drum. The tube bank is located in the path of the effluent gases exiting from the bed and a baffle system is provided to separate the solid particulate matter from the effluent gases. The particulate matter is collected and injected back into the fluidized bed.

  19. DOE/ANL/HTRI heat exchanger tube vibration data bank

    International Nuclear Information System (INIS)

    Development of a new heat exchanger tube vibration data bank at Argonne National Laboratory is described. Comprehensive case histories on heat exchangers that have experienced tube-vibration problems and units that have been trouble-free are accumulated and this information is rendered available for evaluation, improvement, and development of vibration-prediction methods and design guidelines. Discussions include difficulties in generating a data bank, data form development, and solicitation efforts. Also included are 15 case histories upon which the data bank will be built. As new case histories are received, they will be assembled and published as addenda to this report

  20. Heat exchangers for high-temperature thermodynamic cycles

    International Nuclear Information System (INIS)

    The special requirements of heat exchangers for high temperature thermodynamic cycles are outlined and discussed with particular emphasis on cost and thermal stress problems. Typical approaches that have been taken to a comprehensive solution intended to meet all of the many boundary conditions are then considered by examining seven typical designs including liquid-to-liquid heat exchangers for nuclear plants, a heater for a closed cycle gas turbine coupled to a fluidized bed coal combustion chamber, steam generators for nuclear plants, a fossil fuel-fired potassium boiler, and a potassium condenser-steam generator. (auth)