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1

Helixchanger, advanced shell and tube heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

This article discusses the effectiveness of heat exchangers, and describes shellside flows and helical baffle enhancement technology, tube and tubeside enhancement technologies, and the cost of heat exchangers, retrofitting exchangers, and design are considered. (UK)

Van Der Ploeg, H.J. [ABB Lummus Heat Transfer B.V., Voorburg (Netherlands)

1996-12-01

2

PENGARUH PENGGUNAAN BAFFLE PADA SHELL-AND-TUBE HEAT EXCHANGER  

Directory of Open Access Journals (Sweden)

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.

Ekadewi Anggraini Handoyo

2001-01-01

3

Optimum design of shell-and- tube heat exchanger  

International Nuclear Information System (INIS)

[en] Optimization of shell-and-tube heat exchanger is accomplished by use of the OPTIMIZER software package. The objective function is defined together with the implicit constraint. The simultaneous equation solving method is used to solve the equations that describe the process. The advantages of the simultaneous equations solving approach are that: (1) it is a natural way to specify a problem since the design problem is by nature an optimization problem and the engineer does not have any other criterion for specifying many arbitrary variables, (2) it is easy to specify variables and constraints, and (3) it can handle highly integrated systems since all equations are solved simultaneously. The extended Complex algorithm is chosen for such optimization study. The optimal value of the objective function and appropriate design variables are obtained. (author). 8 refs., 1 tab

1996-01-01

4

PENGARUH KECEPATAN ALIRAN TERHADAP EFEKTIVITAS SHELL-AND-TUBE HEAT EXCHANGER  

Directory of Open Access Journals (Sweden)

Full Text Available As a device to exchange heat from hot fluid to colder fluid, a heat exchanger is supposed to have high effectiveness. Theoretically, the increase of fluid rate would increase the effectiveness. Yet, it makes the contact time among the fluids become shorter. Based on this phenomenon, a research is carried on to find out how the fluid rate affects the effectiveness of a Shell-and-Tube Heat Exchanger. The working fluid used is air. It is found out that the effectiveness would up to a certain value if the fluid rate increases and then it would decrease. The effectiveness of a Shell-and-Tube Heat Exchanger would be higher if the hot air flows faster (in the tube side) and the cold air flows slower (in the shell side). Abstract in Bahasa Indonesia : Sebagai alat untuk penukaran panas dari fluida dengan temperatur tinggi ke fluida dengan temperatur rendah, suatu heat exchanger diharapkan mempunyai efektivitas yang tinggi. Secara teoritis kenaikan kecepatan aliran akan menaikkan efektivitas. Namun, hal ini membuat waktu kontak menjadi singkat. Dari fenomena ini, ingin diteliti bagaimana pengaruh kecepatan terhadap efektivitas suatu Shell-and-Tube Heat Exchanger dengan udara sebagai fluida kerja. Dari hasil penelitian didapat bahwa efektivitas naik seiring dengan kenaikan kecepatan hingga suatu harga tertentu dan kemudian akan turun. Efektivitas Shell-and-Tube Heat Exchanger lebih tinggi jika udara panas mengalir dengan kecepatan tinggi (di sisi tube) dan udara dingin mengalir dengan kecepatan rendah (di sisi shell). Kata kunci: efektivitas, shell-and-tube heat exchanger.

Ekadewi Anggraini Handoyo

2000-01-01

5

Assessment of Real Heat Transfer Coefficients through Shell and Tube and Plate Heat Exchangers  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this paper is to present a procedure used in the assessment of the real heat transfer characteristic of shell and tube and plate heat exchangers. The theoretical fundamentals of the procedure are introduced as well as the measured data collection and processing. The theoretical analysis is focused on the adoption of criterial equations which, subjected to certain verification criteria presented in the paper, provide the most credible value of the convection heat transfer coefficients inside the circular and flat tubes. In the end two case studies are presented, one concerning a shell and tube heat exchanger operational at INCERC Thermal Substation and the other concerning a plate heat exchanger tested on the Laboratory Stand of the Department of Building Services and Efficient Use of Energy in Buildings of INCERC Bucharest.

Dan CONSTANTINESCU; Horia PETRAN

2011-01-01

6

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.

1997-01-01

7

Three-dimensional computer simulation of shell and tube heat exchangers  

International Nuclear Information System (INIS)

A three dimensional, conservative, fully implicit, colocated control volume based calculation procedure is described for the simulation of shell side flow in shell and tube heat exchangers. The colocated method uses momentum interpolation to avoid an oscillatory pressure field, and incorporates a flexible boundary condition interface that permits the specification of a wide range of problems. The simulation of shell and tube heat exchangers is based on a distributed resistance method and employs a two-equation ?-? turbulence model. Volume porosities and non homogeneous surface permeabilities account for the obstructions due to the tubes and arbitrary arrangement of baffles. Geometry generators for tubes, baffles and inlets have been created. Non-equilibrium wall functions (Launder and Spalding, 1974) are used to compute momentum and heat transfer coefficients close to plane surface walls. Various test problems presented include the driven cavity, a laminar backward facing step with heat transfer, a turbulent backward facing step with heat transfer, and turbulent sudden pipe expansion. Good agreement is obtained between the computations and experiments and the computations of other researchers. A No Tubes In Window (NTIW) heat exchanger simulation is compared with experimental data. This work forms a basis for studying the significance of geometry on the mixing and heat transfer process in shell and tube heat exchangers.

1995-01-01

8

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)

2009-01-01

9

Performance Analysis of Shell and Tube Heat Exchanger Using Miscible System  

Directory of Open Access Journals (Sweden)

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.

M. Thirumarimurugan; T. Kannadasan; E. Ramasamy

2008-01-01

10

An expert model for the shell and tube heat exchangers analysis by artificial neural networks  

Directory of Open Access Journals (Sweden)

Full Text Available Due to the importance of heat exchangers in chemical and petrochical industries, heat exchangers analysis and heat translate calculations are preceded. The conventional and prevalent methods (such as KERN method and etc) are presented heat translate calculation for the analysis and selection of shell and tube heat exchanger based on the obtained pressure drop and fouling factor after consecutive calculation. Also there are many properties and parameters in prevalent methods. The current work proposed a new method based on the artificial neural network (ANN) for the analysis of Shell and Tube Heat Exchangers. Special parameters for heat exchangers analysis were obtained by neural network and the required experimental data were collected form Kern’s book, TEMA and Perry’s handbook. The work used back- propagation learning algorithm incorporating levenberg - marquardt training method. The accuracy and trend stability of the trained networks were verified according to their ability to predict unseen data. MSE error evaluation was used and the error limitation is 10-3-10-6. Parameters can be obtained without using charts, different Tables and complicated equations. During this research, Twenty two networks were utilized for all different properties. The results demonstrated the ANN’s capability to predict the analysis.

A. R. Moghadassi; S. M. Hosseini; F. Parvizian; F. Mohamadiyon; A. Behzadi Moghadam; A. Sanaeirad

2011-01-01

11

The application of field synergy number in shell-and-tube heat exchanger optimization design  

Energy Technology Data Exchange (ETDEWEB)

In the present work the field synergy principle is applied to the optimization design of the shell-and-tube heat exchanger with segmental baffles. The field synergy number which is defined as the indicator of the synergy between the velocity field and the heat flow is taken as the objective function. The genetic algorithm is employed to solve the heat exchanger optimization problems with multiple design variables. The field synergy number maximization approach for heat exchanger optimization design is thus formulated. In comparison with the initial design, the optimal design leads to a significant cost cut on the one hand and an improvement of the heat exchanger performance on the other hand. The comparison with the traditional heat exchanger optimization design approach with the total cost as the objective function shows that the field synergy number maximization approach is more advantageous. (author)

Guo, Jiangfeng; Xu, Mingtian; Cheng, Lin [Institute of Thermal Science and Technology, Shandong University, Jinan 250061 (China)

2009-10-15

12

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

Energy Technology Data Exchange (ETDEWEB)

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.

Ozden, Ender [Department of Mechanical Engineering, Middle East Technical University, 06531 Ankara (Turkey); Tari, Ilker, E-mail: itari@metu.edu.t [Department of Mechanical Engineering, Middle East Technical University, 06531 Ankara (Turkey)

2010-05-15

13

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.

2010-01-01

14

Modelling of shell and tube heat exchangers with finite element method  

Energy Technology Data Exchange (ETDEWEB)

Fluid flow and heat transfer in shell and tube heat exchangers were considered. Velocity field was treated with the continuity and Navier-Stokes equations. They were modified with the theory of porous media represented by a tube bundle. Fluctuations were treated with the partial differential equation of kinetic energy of turbulence. Temperature field was expressed by the partial differential equation of energy, while heat exchange was expressed by the velocity field and dimensionless equations. The system of partial differential equations was solved with the finite element method. A twenty-node paralleliped was used. The results of measurements were compared with models from the literature and with those of the developed mathematical model. The visualized fluid flow was compared with the calculated one. (orig.)

Hafner, J. [LTH, Skofja Loka (Slovenia)

1995-12-31

15

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.

1976-01-01

16

Dynamic characteristics of various shell-and-tube heat exchangers and modeling from the viewpoint of the network theory  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a network-theoretical approach to the modeling on the dynamic characteristics of the shell-and-tube heat exchangers. Taking into account the phase conditions of hot and cold fluids upon heat-exchange, the shell-and-tube heat exchangers are classified into four types. At the same time, not only the steady state but also dynamic characteristics of the heat exchangers are classified into four types. Therefore they are usually considered and treated as different heat exchangers. In this paper, the dynamic characteristics of the four types of shell-and-tube heat exchangers are investigated theoretically. As a result, the authors derived the model on the dynamic characteristic of each type of the heat exchangers from the viewpoint of the network theory. In this model, the hot and cold fluid processes are represented as 2-port network elements interconnected, and each process consists of thorough variable sources and admittances in parallel. According to this model, the investigation on these admittances gives them important information on the dynamic characteristics of the shell-and-tube heat exchangers.

Amano, Yoshiharu [Waseda Univ., Tokyo (Japan). Advanced Research Center for Science and Engineering; Hashizume, Takumi; Machiyama, Tadahiro [Nippon Inst. of Tech., Saitama (Japan)

1994-12-31

17

Supercritical heat exchanger field test (SHEFT), I. Field performance data on shell-and-tube heat exchangers in geothermal service  

Energy Technology Data Exchange (ETDEWEB)

Field performance data on shell-and-tube heat exchangers in geothermal service are presented. The test data were taken for geothermal brine on the tube side and hydrocarbon on the shell side in counterflow for six primary heat exchangers, and for hydrocarbon on the shell side and cooling water on the tube side for the condenser. Test data were for heating isobutane, 1 90/10 isobutane/isopentane mixture, and a 80/20 isobutane/isopentane mixture at supercritical conditions in the vicinity of their critical pressure and temperature, and for condensing the same fluids. The test data were used in a preliminary data analysis to determine the reported heat exchanger performance parameters.

Silvester, L.F.; Beaulaurier, L.O.; Mirk, K.F.; Fulton, R.L.

1981-06-01

18

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

2002-07-01

19

The performance in shell-and-tube heat exchangers with configuration and surface characteristics of tube  

International Nuclear Information System (INIS)

This paper presents an improved performance of heat transfer for shell-and-tube and thermal analysis based on the Bell-Delaware method for single tube. Heat transfer has been compared for a smooth tube, helical tube and surface-coated tube. In general, the results showed that properly designed helical tube and surface-coated tube offer a significant improvement in heat transfer. The numerical results derived from the Bell-Delaware method for the shell-side heat transfer coefficient were verified with experimental results. The thermal analysis aids significantly in the solution of the design problem.

2008-01-01

20

Computer-Aided Thermohydraulic Design of TEMA Type E Shell and Tube Heat Exchangers for Use in Low Pressure, Liquid-to-Liquid, Single Phase Applications.  

Science.gov (United States)

Classification, nomenclature, utilization and cost estimating of shell and tube heat exchangers are presented along with an historical overview of various methods currently employed in their design. A procedure for providing preliminary estimates of shell...

N. J. Kolar

1985-01-01

 
 
 
 
21

Hydrodynamic diagnosis of a shell-and-tube heat exchanger using tracers - comparison of global and local approaches  

Energy Technology Data Exchange (ETDEWEB)

The global performances of heat exchangers are lowered by flow maldistribution. Furthermore, fouling increases in the dead zones and the residence time may be increased. Such phenomena can induce degradation of heat-sensitive products. In any case, the consequences are higher operating costs and lower quality products. It is thus important to be able to diagnose the hydrodynamic state of a heat exchanger while it is running. In this paper, we present two diagnosis methods, a global approach and a Computational Fluid Dynamics approach, based on the comparison between tracer experiments and numerical models. Furthermore, it is interesting for a given geometry, to compare these two techniques. An hydrodynamic study of a shell-and-tube heat exchanger will illustrate these questions. (authors)

Albaric, M.; Bandelier, P. [CEA Grenoble, GRETh, 38 (France); Jallut, C. [Universite Claude Bernard, LAGEP, ESCPE-CNRS, UMR 5007, 69 - Villeurbanne (France)

2001-07-01

22

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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....

Mohammadi, Koorosh

23

A study on the development of fouling analysis technique for shell-and-tube heat exchangers  

International Nuclear Information System (INIS)

Fouling of heat exchangers is generated by water-borne deposits, commonly known as foulants including particulate matter from the air, migrated corrosion produces; silt, clays, and sand suspended in water; organic contaminants; and boron based deposits in plants. The fouling is known to interfere with normal flow characteristics and reduce thermal efficiencies of heat exchangers. This paper describes the fouling analysis technique developed in this study which can analyze the thermal performance for heat exchangers and estimate the future fouling variations. To develop the fouling analysis technique for heat exchangers, fouling factor was introduced based on the ASME O and M codes and TEMA standards. For the purpose of verifying the fouling analysis technique, the fouling analyses were performed for four heat exchangers in several nuclear power plants; two residual heat removal heat exchangers of the residual heat removal system and two component cooling water heat exchangers of the component cooling water system.

2004-01-01

24

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

Directory of Open Access Journals (Sweden)

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.

V. Alagesan; S. Sundaram

2012-01-01

25

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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 (more) = 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.

Alagesan, V.; Sundaram, S.

2012-06-01

26

Ageing studies on shell and tube type heat exchangers at Cirus based on field experience and inservice inspection  

International Nuclear Information System (INIS)

Cirus is a 40 MWt research reactor located at Trombay, Bombay and commissioned in the year 1960. The reactor uses metallic natural uranium as fuel, demineralized (DM) light water as primary coolant, heavy water as moderator and sea water as secondary coolant. A set of 13 nos. of shell and tube type heat exchangers are used in the main systems for rejecting heat to sea. The heat exchangers are vertically mounted, conforming to TEMA Class R and 70:30 Cu-Ni tubes on sea water side. End covers are made of Si-bronze. The heat exchangers have given satisfactory service for over 33 years. In the initial years, problems such as fouling on sea water side and failure of a few tubes near the sea water entry zones were experienced. Subsequently, the maintenance work greatly reduced after carrying out certain modifications in the operations and maintenance procedures. In-service inspection carried out and the maintenance experience suggest that performance of the heat exchangers may be rated as satisfactory. Deformation of some components, damage to tubes on the DM water side, cracking of heavy water heat exchanger shell (SS type 347) due to intergranular stress corrosion cracking (IGSCC) etc. have been observed. An attempt is made to discuss the experience. (author). 2 refs., 3 tabs., 3 figs

1994-01-01

27

Transient simulation and experimental verification of gas-steam and liquid-steam, shell and tube type heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

In order to develop advanced control systems for complex chemical processes, the engineer must be able to reliably predict the transient response of all of the components in the system. This paper reports on part of an on-going project to develop an experimentally verified engineering tool for developing controls of a coal gasification fuel plant. More specifically, this paper describes the development of models for steam heaters, a common component in any chemical process. The condensing steam heaters dynamically modeled in this work are shell and tube heat exchangers with the condensing steam on the shell side. Two variations of the model are developed, one for heating a gas stream where the thermal mass of the gas is neglected, and one for heating a liquid stream where the thermal mass of the heated fluid may not be neglected. Predictions from the gas heater model compare excellently with data collected from transient experiments on two industrial heat exchangers at the General Electric Coal Gasification Process Evaluation Facility. These two heat exchangers differ widely in their design and operating conditions. Consequently, the good agreement that was found between the model predictions and experimental data shows the wide applicability of the model. 2 references, 3 figures.

Daniel, K.J.; Crapo, A.W.; Brown, D.H.

1984-01-01

28

Plugging margin evaluation considering the fouling of shell-and-tube heat exchanger  

International Nuclear Information System (INIS)

As operating time of heat exchangers progresses, fouling generated by water-borne deposits increases, number of tube plugging increases, and thermal performance decreases. The fouling and plugging of tubes are known to interfere with normal flow characteristics and reduce thermal efficiencies of heat exchangers. This paper describes the plugging margin evaluation method which can reflect the current fouling level developed in this study. To develop the plugging margin evaluation methods for heat exchangers, fouling factor was introduced based on the ASME O and M codes and TEMA standards. For the purpose of verifying the plugging margin evaluation methods, the fouling and plugging margin evaluations were performed for a component cooling heat exchanger in a nuclear power plant.

2003-01-01

29

Helical baffles in shell-and-tube heat exchangers. Part 1: Experimental verification  

Energy Technology Data Exchange (ETDEWEB)

Performance of heat exchangers with helical baffles, or helixchangers, is discussed using the results of tests conducted on units with various baffle geometries. An optimum helix angle is identified at which the conversion efficiency for converting pressure drop to heat transfer on the shell side of helixchangers is maximized. Designs for standard industry applications are optimized using the analysis of test results.

Kral, D.; Stehlik, P.; Ploeg, H.J. Van Der; Master, B.I.

1996-01-01

30

Performance of a two-phase closed thermosyphon solar collector with a shell and tube heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

In the present study, a two-phase closed thermosyphon flat-plate solar collector with a shell and tube heat exchanger was investigated experimentally under the field conditions of Cairo, Egypt. The collector was designed, constructed, and tested at transient conditions to study its performance for different cooling water mass flow rates at different inlet cooling water temperatures. Also the effect of the number of the thermosyphon tubes on the performance of the collector was investigated. Under different climate conditions, the experimental results showed that the optimal mass flow rate is very close to the ASHRAE standard mass flow rate for testing conventional flat-plate solar collectors. Also, the experimental results indicated that the number of the thermosyphon tubes has a significant effect on the collector efficiency. The performance of the present collector with optimum number of thermosyphon tubes was compared with the performance of two-phase closed thermosyphon flat-plate solar collectors with tube in tube heat exchangers of previous investigators and a better performance for the present collector was obtained at high inlet water temperature. (author)

Nada, S.A. [Benha High Institute of Technology (Egypt). Dept. of Mechanical Engineering; El-Ghetany, H.H.; Hussein, H.M.S. [National Research Center, Dokki (Egypt). Dept. of Solar Energy

2004-09-01

31

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)

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.

Raj Karuppa Thundil R.; Ganne Srikanth

2012-01-01

32

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)

[en] 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)

1981-12-18

33

Experimental determination of shell side heat transfer coefficient and pressure drop for an oil cooler shell-and-tube heat exchanger with three different tube bundles  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the heat transfer coefficient and pressure drop on the shell side of a shell-and-tube heat exchanger have been experimentally obtained for three different types of copper tubes (smooth, corrugated and with micro-fins). Also, experimental data has been compared with theoretical data available. Correlations have been suggested for both pressure drop and Nusselt number for the three tube types. A shell-and-tube heat exchanger of an oil cooler used in a power transformer has been modeled and built for this experimental work in order to investigate the effect of surface configuration on the shell side heat transfer as well as the pressure drop of the three types of tube bundles. The bundles with the same geometry, configuration, number of baffles and length, but with different external tube surfaces inside the same shell were used for the experiment. Corrugated and micro-fin tubes have shown degradation of performance at a Reynolds number below a certain value (Re<400). At a higher Reynolds number the performance of the heat exchanger greatly improved for micro-finned tubes. (author)

Hosseini, R.; Hosseini-Ghaffar, A. [Faculty of Mechanical Engineering Amirkabir University of Technology, 424 Hafez Avenue, P.O. Box 15875-4413, Tehran (Iran); Soltani, M. [Mechanical Systems Department, Niroo research Institute (NRI), End of Pounak Bakhtari Blvd., P.O. Box 14665-517, Shahrak Gharb, Tehran (Iran)

2007-04-15

34

A study on the development of plugging margin evaluation method reflected the fouling of a shell-and-tube heat exchanger  

International Nuclear Information System (INIS)

As operating time of heat exchangers progresses, fouling generated by water-borne deposits and the number of plugged tubes increase and thermal performance decreases. Both fouling and tube plugging are known to interfere with normal flow characteristics and to reduce thermal efficiencies of heat exchangers. The heat exchangers of domestic nuclear power plants have been analyzed in terms of the heat flux and heat transfer coefficient at test conditions as a means of heat exchanger management. Except for the fouling level generated in operation of heat exchangers, also, all of the tubes of heat exchangers have been replaced when the number of plugged tubes exceeds the plugging criteria based on design performance sheet. This paper describes the plugging margin evaluation method reflected the fouling of shell-and-tube heat exchangers, which can evaluate the thermal performance for heat exchangers, estimate the further fouling variations, and reflect the current fouling level. To identify the effectiveness of the developed method, the fouling and plugging margin evaluations were performed for a component cooling heat exchanger in a nuclear power plant.

2004-01-01

35

A study on development of a plugging margin evaluation method taking into account the fouling of shell-and tube heat exchangers  

International Nuclear Information System (INIS)

As the operating time of heat exchangers progresses, fouling caused by water-borne deposits and the number of plugged tubes increase and thermal performance decreases. Both fouling and tube plugging are known to interfere with normal flow characteristics and to reduce thermal efficiencies of heat exchangers. The heat exchangers of Korean nuclear power plants have been analyzed in terms of heat transfer rate and overall heat transfer coefficient as a means of heat exchanger management. Except for fouling resulting from the operation of heat exchangers, all the tubes of heat exchangers have been replaced when the number of plugged tubes exceeded the plugging criteria based on design performance sheet. This paper describes a plugging margin evaluation method taking into account the fouling of shell-and-tube heat exchangers. The method can evaluate thermal performance, estimate future fouling variation, and consider current fouling level in the calculation of plugging margin. To identify the effectiveness of the developed method, fouling and plugging margin evaluations were performed at a component cooling heat exchanger in a Korean nuclear power plant

2006-01-01

36

A study on the development of fouling and plugging margin evaluation methods for shell-and-tube heat exchangers  

International Nuclear Information System (INIS)

As operating time of heat exchangers progresses, fouling generated by water-borne deposits increases and thermal performance decreases. The fouling is known to interfere with normal flow characteristics and reduce thermal efficiencies of heat exchangers. The heat exchangers of nuclear power plants have been analyzed in terms of the heat flux and heat transfer coefficient at test conditions based on the ASME OM-S/G-Part 2 as a means of heat exchanger management. It is hard to estimate the heat performance trend and to establish the future management plan. This paper describes the fouling evaluation method which can evaluate the thermal performance for heat exchangers and estimate the future fouling variations and the plugging margin evaluation method which can reflect the current fouling level developed in this study. To develop the fouling and plugging margin evaluation methods for heat exchangers, fouling factor was introduced based on the ASME O and M codes and TEMA standards. For the purpose of verifying the two evaluation methods, the fouling and plugging margin evaluations were performed for a component cooling heat exchanger in a nuclear power plant.

2003-01-01

37

Simple-type shell-and-tube Heat exchanger bench with coupled data acquisition system and simulation software; Bancada de trocador de calor tubo duplo com sistema de aquisicao de dados e software de simulacao acoplados  

Energy Technology Data Exchange (ETDEWEB)

The main objective of this work is upgrading a simple-type shell-and-tube experimental heat exchanger, that exist at the DETF Didactic Thermal Laboratory. With the inclusion of a dattalogger and a processor software we actualize the apparatus. We also describe the software Exchange designed specially for this experimental set. The Exchange solves the heat exchange equations and compare the theoretical results with the experimental results. (author)

Barbedo, Renato Pimentel; Sanchez, Caio Glauco

1998-07-01

38

Fluid thermal physics properties change effects on convective coefficients in shell-and-tube heat exchangers; Efecto de la variacion de las propiedades termo fisicas de los fluidos sobre los coeficientes convectivos en intercambiadores de calor de carcasa y tubos  

Energy Technology Data Exchange (ETDEWEB)

In this work the effect that is produced considering the local value of the thermo-physical properties of the fluids, on the convective coefficients in shell-and-tube heat exchangers, was determined. In order to obtain the temperature distribution, the exchanger was discretized in elements, which allowed to compute the thermo-physical properties and the local convective coefficients, on the shell side and on the tubes side as well. With these results mean convective coefficients were evaluated and compared with those obtained by the logarithmic-mean-temperature-difference method, obtaining a difference less than two percent which does not affect the final result of the exchanger. (author)

Garcia, Francisco [Universidad Central de Venezuela, Caracas (Venezuela). Facultad de Ingenieria; Segura, Julio [Universidad Metropolitana, Caracas (Venezuela)

1996-07-01

39

Application of a stepwise method for analyzing fouling in shell-and-tube exchangers  

Energy Technology Data Exchange (ETDEWEB)

This article presents the results of the application of a quite simple method for analyzing shell-side fouling in shell-and-tube exchangers, capable of taking into account the formation or irregular fouling deposits with variable thermal conductivity. This method, based on the utilization of elementary heat exchangers, has been implemented for E-shell TEMA-type heat exchangers with two tube passes. Several fouling deposit distributions have been simulated so as to ascertain their effects on the heat transfer rate. These distributions consider that fouling is concentrated in zones where the temperature of the fluids is maximum or minimum.

Prieto, M.M.; Miranda, J.; Sigales, B.

1999-12-01

40

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)

Full Text Available Abstract in spanish 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 diferentes parámetros de diseño y condiciones de operación variables. El software permite modificar condiciones tanto de operación como de diseño, por ejemplo, temperatura y c (more) audales 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 conditions. 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.

Machuca, Fiderman; Urresta, Oscar

2008-06-01

 
 
 
 
41

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

Directory of Open Access Journals (Sweden)

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.

Bukin Vladimir Grigorievich; Ho Viet Hung

2013-01-01

42

Heat transfer coefficient in water-sodium shell-and-tube steam generators  

International Nuclear Information System (INIS)

[en] This paper is related to heat transfer in a shell-and-tube steam generator and provides a comparison between experimental data and results obtained by a simple theoretical model deduced by empirical correlations. The experimental work was carried out in a 50 MW steam generatorprototype for a nuclear fast breeder ractor. Several correlations for the heat transfer coefficients are considered for the preheater (single phase) and the region of subcooled, nucleate, post dry-out boiling (two phase flow). Several temperature distributions are obtained and the configuration best in agreement with the experimental data and the pertinent correlations are emphasized

1985-01-01

43

1-2 N shell-and-tube exchanger effectiveness: A simplified Kraus-Kern equation  

Energy Technology Data Exchange (ETDEWEB)

Kraus and Kern derived for heat exchangers a relationship between the temperature effectiveness of the tube side stream,the number of heat transfer units based on the tube-side heat capacity rate and the heat capacity ratio of the tube to the shell. This paper is aimed at further simplification of the Kraus-Kern formula and provides analytical proof for a limiting process for the effectiveness of heat exchangers that was intuitively considered in various texts but whose analytical proof was not available in the literature.

Baclic, B.S. (Univ. of Novi Sad, Zrenjanin (Yugoslavia))

1989-02-01

44

Integrated nitrogen removal in a shell-and-tube co-immobilized cell bioreactor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new bioreactor (shell-and-tube co-immobilized cell bioreactor) for integrated nitrogen removal from wastewater was developed. The configuration of this bioreactor was similar to a shell-and-tube heat exchanger, and consisted of a bundle of parallel tubes made up of polyvinyl alcohol (PVA) gel, con...

Cao, GM; Zhao, QX; Sun, XB; Zhang, T

45

Effect of surface conditions on boiling heat transfer of refrigerants in shell-and-tube evaporators  

International Nuclear Information System (INIS)

Experimental results are presented for the boiling heat transfer performance of R 22 and R 717 on surfaces with porous metallized coatings. A calculational-theoretical model is given for predicting the heat transfer of refrigerants boiling on a bundle of finned tubes.

1990-01-01

46

Enhanced shell-and-tube heat eschangers for the power and process industries. Final report  

Energy Technology Data Exchange (ETDEWEB)

Single-tube pool boiling tests were performed with saturated pure refrigerants and binary mixtures of refrigerants. Generally, with pure refrigerants, the High Flux surface performed better at the higher heat fluxes compared to the Turbo-B tube, and both enhanced surfaces performed significantly better than smooth surface. In tests of R-11/R-113 mixtures, the enhanced surfaces had much less degradation in heat transfer coefficient due to mixture effects compared to smooth tubes; the largest degradation occurred at a mixture of 25% R-11/75% R-113. Under boiling in saturated aqueous solution of calcium sulfate, with a single tube, effects of fouling were more pronounced at the higher heat fluxes for all surfaces. Two staggered tube bundles were tested with tube pitch-diameter ratios of 1.17 and 1.50. For the pure refrigerant, tests on the smooth-tube bundle indicated that the effects on the heat transfer coefficient of varying mass flux, quality, and tube-bundle geometry were small, except at low heat fluxes. Neither enhanced surface showed any effect with changing mass flux or quality. The binary mixture bundle-boiling tests had results that were very similar to those obtained with the pure refrigerants. When boiling a refrigerant-oil mixture, all three surfaces (smooth, High Flux, and Turbo-B) experienced a degradation in its heat transfer coefficient; no surface studied was found to be immune or vulnerable to the presence of oil than another surface.

Bergles, A.E.; Jensen, M.K.; Somerscales, E.F.; Curcio, L.A. Jr.; Trewin, R.R.

1994-08-01

47

Heat Exchanger  

International Nuclear Information System (INIS)

A liquid metal heated tube and shell heat exchanger where straight tubes extend between upper and lower tube sheets. In order to prevent thermal stress problems, one tube sheet is fixed to the shell, and the other tube sheet is sealed to the shell by means of a flexible bellows. In the event of a catastrophic bellows failure, a housing that utilizes a packing gland sliding seal is used to enclose and back-up the bellows. Also, a key and slot arrangement is provided for preventing relative rotation between the shell and tube sheet which could damage the bellows and cause failure thereof. This exchanger is seen to be of use in sodium cooled reactors between the liquid sodium circuit on the steam generator

1976-07-15

48

Design of heat exchangers by numerical methods  

International Nuclear Information System (INIS)

Differential equations describing the heat tranfer in shell - and tube heat exchangers are derived and solved numerically. The method of ?T sub(lm) is compared with the proposed method in cases where the specific heat at constant pressure, Cp and the overall heat transfer coefficient, U, vary with temperature. The error of the method of ?T sub (lm) for the computation of the exchanger lenght is less than + 10%. However, the numerical method, being more accurate and at the same time easy to use and economical, is recommended for the design of shell-and-tube heat exchangers. (Author)

1981-12-18

49

Improvements of common and specific types of heat exchangers; Zowel gangbare als specifieke typen warmtewisselaars verbeterd  

Energy Technology Data Exchange (ETDEWEB)

A brief overview is given of the principles and the technical improvements of several types of heat exchangers: coil or shell and tube heat exchangers, fluidized-bed heat exchanger, plate heat exchanger, and a plate-fin heat exchanger. The improvements result in a broader application area of those heat exchangers. 2 figs.

Voorter, P. [ed.

1997-08-01

50

A core alternative[Heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The development of the efficient Core-in-kettle heat exchangers by Chart Heat Exchangers as an alternative to shell and tube exchangers is reported, and its use as condensers and reboilers in ethylene plants and refrigerant condensers and chillers in natural gas processing and liquid natural gas (LNG) plants are discussed. The novel technology is described with details given of the replacement of the tube bundle with a Chart brazed aluminium plate-fin heat exchanger core, the operation of the exchanger, the savings achieved by installing these heat exchangers in new or existing plants, and Core-in-Kettle retrofits of existing shell and tube heat exchangers. The limitations of the use of Core-in-Kettle heat exchangers to clean fluids typical of hydrocarbon processing, and temperature and pressure limitations are noted.

Weaver, R.H. [Chart Heat Exchangers, Wisconsin (United States)

2001-09-01

51

Chapter 11. Heat Exchangers  

Energy Technology Data Exchange (ETDEWEB)

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.

Rafferty, Kevin D.; Culver, Gene

1998-01-01

52

Feasibility study of improved heat exchanger  

International Nuclear Information System (INIS)

Generally shell and tube type heat exchangers have been used widely for many years in the auxiliary cooling systems of nuclear power plants. Recently, however, in general industrial facilities and so on many plate heat exchangers excellent in heat transfer performance have been used, compared with shell and tube heat exchangers, and their heat exchanger bodies and cooling system facilities have been rationalized. We carried out confirmation tests on the plate type heat exchangers in structural strength, aseismatic strength, heat transfer performance and maintenance regarding their application to nuclear power plants. As a result, we have confirmed that they can be applied to seawater systems of actual plants. The tests further provided useful information on their actual operation. (author)

1991-01-01

53

Digital simulation of transients in a sodium-sodium intermediary heat exchanger  

International Nuclear Information System (INIS)

A computer program to simulate a sodium-sodium heat exchanger in normal and abnormal operation was developed. Two simplifications were used : rate of flow spatially uniform and shell and tube model. (E.G.)

1983-01-01

54

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

International Nuclear Information System (INIS)

[en] 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)

2010-01-01

55

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

1983-01-01

56

Modelling of natural-convection driven heat exchangers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract: A lumped model is developed for shell-and-tube heat exchangers driven by natural convection, which is based on a one-dimensional approximation. The heat flux is driven by the logarithmic mean temperature difference. The volumetric air flow rate is driven by the buoyant force. Based on ...

Dirkse, M.H.; Loon, W.K.P., van; Stigter, J.D.; Bot, G.P.A.

57

Conquer heat exchanger fouling  

Energy Technology Data Exchange (ETDEWEB)

Fouling plays a dominant role in heat exchanger performance. It is extremely important to choose the most appropriate type of heat exchanger for a particular application and adopt proper values for fouling resistance. A design practice for shell-and-tube heat exchangers that will limit fouling to a minimum and thus ensure trouble-free operation is essential. Due to the availability of specialized software, the thermal design of heat exchangers has become precise and scientific. The results occasionally have to be tempered with practical experience and engineering judgment, but generally these computer programs are very reliable and authentic. However, the above is true only for determining heat-transfer coefficients and pressure drop. One important area that cannot possibly be addressed by design software is fouling. While a proper selection of fouling resistance is extremely difficult due to the numerous factors involved, a sound design practice will minimize any errors. However, it is important to first understand the phenomenon of fouling. The paper describes what fouling is, types of fouling, factors affecting fouling, providing a fouling allowance, selecting a fouling resistance, and overcoming fouling through better design.

Mukherjee, R. [Engineers India Ltd., New Delhi (India)

1996-01-01

58

An investigation into fouling of a printed circuit heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A facility has been built to compare the fouling propensity of two heat exchangers operating with cooling water from an open cooling tower. Tests were carried out with a Printed Circuit Heat Exchanger and a heat exchanger having tube dimensions representative of a typical industrial shell-and-tube unit. The results of the tests showed that a Printed Circuit Heat Exchanger can operate satisfactorily with cooling water providing that the chemical treatment and filtration of the water is adequate. Facilities to permit backwash of the heat exchanger should also be incorporated in any practical application of a Printed Circuit Heat Exchanger with cooling water. (Author)

1991-03-01

59

Heat exchangers: Selection, rating, and thermal design  

Energy Technology Data Exchange (ETDEWEB)

This book takes a systematic approach to the subject, focusing on the selection, design, rating, and operational challenges of various types of heat exchangers. Written by well-known authors in the field of heat transfer, this book covers all the most commonly used types of heat exchangers, including condensers and evaporators. The text begins with the classification of the different types of heat exchangers and discusses methods for their sizing and rating. Single phase forced convection correlations in ducts and pressure drop and pumping power analysis are also covered. A chapter is devoted to the special problem of fouling. Thermal design methods and processes, including designs for condensers and evaporators, complete this thorough introduction to the subject. The appendix provides information on the thermophysical properties of fluids, including the new refrigerants. Every topic features worked examples to illustrate the methods and procedures presented, and additional problems are included at the end of each chapter, with examples to be used as a student design project. An instructor's manual is available, including complete solutions to selected problems in the text. The contents include: classification of heat exchangers; basic design methods of heat exchangers; forced convection correlations for single-phase side of heat exchangers; heat exchanger pressure drop and pumping power; fouling of heat exchangers; double-pipe heat exchangers; design correlations for condensers and evaporators; shell-and-tube heat exchangers; compact heat exchangers; gasketed-plate heat exchangers; and condensers and evaporators.

Kakac, S.; Liu, H.

1998-01-01

60

Bayonet heat exchangers in heat-assisted Stirling heat pump  

Energy Technology Data Exchange (ETDEWEB)

The Multi-Temperature Heat Supply System is a research project creating a city energy system with lower environmental load. This system consists of a gas-fueled internal combustion engine and a heat-assisted Stirling heat pump utilizing shaft power and thermal power in a combination of several cylinders. The heat pump is mainly driven by engine shaft power and is partially assisted by thermal power from engine exhaust heat source. Since this heat pump is operated by proportioning the two energy sources to match the characteristics of the driving engine, the system is expected to produce cooling and heating water at high COP. This paper describes heat exchanger development in the project to develop a heat-assisted Stirling heat pump. The heat pump employs the Bayonet type heat exchangers (BHX Type I) for supplying cold and hot water and (BHX Type II) for absorbing exhaust heat from the driving engine. The heat exchanger design concepts are presented and their heat transfer and flow loss characteristics in oscillating gas flow are investigated. The main concern in the BHX Type I is an improvement of gas side heat transfer and the spirally finned tubes were applied to gas side of the heat exchanger. For the BHX Type II, internal heat transfer characteristics are the main concern. Shell-and-tube type heat exchangers are widely used in Stirling machines. However, since brazing is applied to the many tubes for their manufacturing processes, it is very difficult to change flow passages to optimize heat transfer and loss characteristics once they have been made. The challenge was to enhance heat transfer on the gas side to make a highly efficient heat exchanger with fewer parts. It is shown that the Bayonet type heat exchanger can have good performance comparable to conventional heat exchangers.

Yagyu, S.; Fukuyama, Y.; Morikawa, T.; Isshiki, N.; Satoh, I.; Corey, J.; Fellows, C.

1998-07-01

 
 
 
 
61

Heat exchanger  

UK PubMed Central (United Kingdom)

The present invention relates to a heat exchanger which is specifically adapted for use in connection with blood oxygenators, particularly bubble oxygenators. The core of the heat exchanger is generally cylindrical and closed at both ends. The cylinder is made of thin walled material with good heat exchange properties such as aluminum. The portion of the heat exchanger core which will be exposed to blood is coated with a biocompatible material such as tetrafluoroethylene. The heat exchanger may be connected to a source of heat exchange medium, such as water, through couplings in the top portion of the heat exchanger core. The heat exchange medium is then circulated through the core providing heating or cooling which is capable of heating or cooling blood within a bubble oxygenator. The heat exchanger core is then nested within a suitable receiver. The inner walls of said receiver may be reticulated in order to facilitate exchange of heat between the heat exchanger core and a fluid, such as blood, flowing between the outer wall of the heat exchanger core and the inner wall of the shell.

OSCARSSON ROLF A

62

Modular heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A shell and tube heat exchanger having a plurality of individually removable tube bundle modules. A lattice of structural steel forming rectangular openings therein is placed at each end of a cylindrical shell. Longitudinal structural members are placed in the shell between corners of the rectangular openings situated on opposite ends of the shell. Intermediate support members interconnect the longitudinal supports so as to increase the longitudinal supports rigidity. Rectangular parallelpiped tube bundle moldules occupy the space defined by the longitudinal supports and end supports and each include a rectangular tube sheet situated on each end of a plurality of tubes extending therethrough, a plurality of rectangular tube supports located between the tube sheets, and a tube bundle module stiffening structure disposed about the bundle's periphery and being attached to the tube sheets and tube supports. The corners of each tube bundle module have longitudinal framework members which are mateable with and supported by the longitudinal support members. Intermediate support members constitute several lattice, each of which is situate d in a plane between the end support members. The intermediate support members constituting the several lattice extend horizontally and vertically between longitudinal supports of adjacent tube module voids. An alternative embodiment for intermediate support members constitute a series of structural plates situated at the corners of the module voids and having recesses therein for receiving the respective longitudinal support members adjacent thereto, protrusions separating the recesses, and a plurality of struts situated between protrusions of adjacent structural plates.

Giardina, Angelo R. (Marple Township, Delaware County, PA)

1981-01-01

63

Operation of a plate-type heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

Osaka Gas has installed a plate-type heat exchanger as the cooler for the liquid circulating through a Fumaks type coke oven gas desulfurization facility. The plate-type construction was adopted after comparative evaluations of plate-type, spiral-type and shell-and-tube-type heat exchangers. Although the liquid flow rate through the Fumaks desulfurization equipment is approximately 14% less than the design flow rate, both the clean heat transfer coefficient (U/SUB/C) and the overall heat transfer coefficient (U/SUB/D) are in line with the original design values. 3 references.

Katagiri, K.; Yasuda, K.

1984-01-01

64

Study on heat transfer of heat exchangers in the Stirling engine - Performance of heat exchangers in the test Stirling engine  

Science.gov (United States)

The heat transfer performance of the actual heat exchangers obtained from the experimental results of the test Stirling engine is presented. The heater for the test engine has 120 heat transfer tubes that consist of a bare-tube part and a fin-tube part. These tubes are located around the combustion chamber and heated by the combustion gas. The cooler is the shell-and-tube-type heat exchanger and is chilled by water. It is shown that the experimental results of heat transfer performance of the heater and cooler of the test Stirling engine are in good agreement with the results calculated by the correlation proposed in our previous heat transfer study under the periodically reversing flow condition. Our correlation is thus confirmed to be applicable to the evaluation of the heat transfer coefficient and the thermal design of the heat exchangers in the Stirling engine.

Kanzaka, Mitsuo; Iwabuchi, Makio

1992-11-01

65

Compact heat exchangers - moving up the learning curve  

Energy Technology Data Exchange (ETDEWEB)

The use of compact heat exchangers for certain applications is discussed and the article focuses on the PCHE (printed circuit heat exchanger) which is manufactured by Heatric Ltd in Poole UK. The manufacturing procedure is described in outline. An application of the PCHE is the titanium unit at BP's Wytch Farm Gathering Centre in Dorset UK where high ambient temperatures in summer were limiting the number of barrels of oil per day. The 1-tonne PCHE was only 5% of the mass of the equivalent shell-and-tube exchanger, and fouling could be controlled.

Reay, D.

1999-12-01

66

Heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger of a type used to transfer heat from exhaust air (for instance air-conditioning) to fresh air is constructed in such way, that an evaporator of the pump circuit is situated after the exit of the exhaust air cooled in the heat exchanger. The condenser of the heat-pumps circuit is in contact with water in a water tank for domestic purposes.

Svendsen, B.R.

1981-02-28

67

Multidimensional numerical modeling of heat exchangers  

Science.gov (United States)

A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchangers for liquid-metal services. For the shellside fluid, the conservation equations of mass, momentum, and energy for continuum fluids are modified using the concept of porosity, surface permeability and distributed resistance to account for the blockage effects due to the presence of heat-transfer tubes, flow baffles/shrouds, the support plates, etc. On the tubeside, the heat-transfer tubes are connected in parallel between the inlet and outlet plenums, and tubeside flow distribution is calculated based on the plenum-to-plenum pressure difference being equal for all tubes. It is assumed that the fluid remains single-phase on the shell side and may undergo phase-change on the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reactor (LMFBR) intermediate heat exchangers (IHX) and steam generators (SG).

Sha, W. T.; Yang, C. I.; Kao, T. T.; Cho, S. M.

68

Multidimensional numerical modeling of heat exchangers. [LMFBR  

Energy Technology Data Exchange (ETDEWEB)

A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchangers for liquid-metal services. For the shellside fluid, the conservation equations of mass, momentum, and energy for continuum fluids are modified using the concept of porosity, surface permeability and distributed resistance to account for the blockage effects due to the presence of heat-transfer tubes, flow baffles/shrouds, the support plates, etc. On the tubeside, the heat-transfer tubes are connected in parallel between the inlet and outlet plenums, and tubeside flow distribution is calculated based on the plenum-to-plenum pressure difference being equal for all tubes. It is assumed that the fluid remains single-phase on the shell side and may undergo phase-change on the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reactor (LMFBR) intermediate heat exchangers (IHX) and steam generators (SG).

Sha, W.T.; Yang, C.I.; Kao, T.T.; Cho, S.M.

1982-01-01

69

Multidimensional numerical modeling of heat exchangers  

International Nuclear Information System (INIS)

A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchangers for liquid-metal services. For the shellside fluid, the conservation equations of mass, momentum, and energy for continuum fluids are modified using the concept of porosity, surface permeability and distributed resistance to account for the blockage effects due to the presence of heat-transfer tubes, flow baffles/shrouds, the support plates, etc. On the tubeside, the heat-transfer tubes are connected in parallel between the inlet and outlet plenums, and tubeside flow distribution is calculated based on the plenum-to-plenum pressure difference being equal for all tubes. It is assumed that the fluid remains single-phase on the shell side and may undergo phase-change on the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reactor (LMFBR) intermediate heat exchangers (IHX) and steam generators (SG)

1982-01-01

70

Heat exchanger  

International Nuclear Information System (INIS)

The arrangement described relates particularly to heat exchangers for use in fast reactor power plants, in which heat is extracted from the reactor core by primary liquid metal coolant and is then transferred to secondary liquid metal coolant by means of intermediate heat exchangers. One of the main requirements of such a system, if used in a pool type fast reactor, is that the pressure drop on the primary coolant side must be kept to a minimum consistent with the maintenance of a limited dynamic head in the pool vessel. The intermediate heat exchanger must also be compact enough to be accommodated in the reactor vessel, and the heat exchanger tubes must be available for inspection and the detection and plugging of leaks. If, however, the heat exchanger is located outside the reactor vessel, as in the case of a loop system reactor, a higher pressure drop on the primary coolant side is acceptable, and space restriction is less severe. An object of the arrangement described is to provide a method of heat exchange and a heat exchanger to meet these problems. A further object is to provide a method that ensures that excessive temperature variations are not imposed on welded tube joints by sudden changes in the primary coolant flow path. Full constructional details are given. (U.K.)

1976-01-01

71

Heat exchanger  

Science.gov (United States)

A heat exchanger is provided having first and second fluid chambers for passing primary and secondary fluids. The chambers are spaced apart and have heat pipes extending from inside one chamber to inside the other chamber. A third chamber is provided for passing a purge fluid, and the heat pipe portion between the first and second chambers lies within the third chamber.

Daman, Ernest L. (Westfield, NJ); McCallister, Robert A. (Mountain Lakes, NJ)

1979-01-01

72

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.

1984-01-01

73

Evaluation Methodology for Advance Heat Exchanger Concepts Using Analytical Hierarchy Process  

Energy Technology Data Exchange (ETDEWEB)

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).

Piyush Sabharwall; Eung Soo Kim

2012-07-01

74

Plate type heat exchanger for Reaktor TRIGA PUSPATI  

International Nuclear Information System (INIS)

[en] 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)

1982-06-28

75

Heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The heat exchange tube described is a light alloy multi-bore extrusion having the walls of the bores dimpled, with the dimples on opposite walls aligned so that each bore consists of a series of chambers along its length. The chambers are connected together by the restricted portion lying between the pair of dimples, and this gives the effect of high turbulation and most efficient heat exchange.

Smith, E.

1985-11-27

76

Improvement of efficiency on ball-cleaning method for JRR-3 heat exchanger  

International Nuclear Information System (INIS)

[en] JRR-3 uses shell and tube heat exchangers. The secondary coolant flushes into the tubes and the primary coolant flows outside of the tubes. The heat exchangers are cleaned with the ball-cleaning method, which is a method to clean inside of the tubes by passing the sponge balls with secondary coolant. Decline in the performance of heat exchanger could rise temperature of the primary coolant and then influence the safe and stable reactor operation. The effective way of ball-cleaning for JRR-3 heat exchangers is examined based on past cleaning data. The results show the optimal ball size and the way to determine the cleaning time. (author)

2008-01-01

77

Heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

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.

Drury, C.R.

1988-02-02

78

Heat exchanger  

International Nuclear Information System (INIS)

This patent describes a method to increase the surface area of a plate or pipe used in a gas-liquid heat exchanger. 6% of the gas side is covered with strands of aluminium or any other good heat conducting material. The strands are 2mm long and have a diameter of 0.1mm. A tenfold increase in surface area is obtained by this method. (Th.P.)

1980-01-01

79

Efficiency improvement of the indirect supercritical CO{sub 2} turbine system for fast reactors by applying micro-channel intermediate heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

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 CO{sub 2} 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*Re{sup 0.61}*Pr{sup 0.4} and friction factor f equals 0.11*Re{sup -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 CO{sub 2} 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.

Yasushi, Muto; Makoto, Mito; Yasuyoshi, Kato; Nobuyoshi, Tsuzuki [Research Laboratory for Nuclear Reactors of Tokyo Institute of Technology, Tokyo (Japan)

2007-07-01

80

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

2007-01-01

 
 
 
 
81

Direct Use Geothermal Applications for Brazed Plate Heat Exchangers  

Energy Technology Data Exchange (ETDEWEB)

Most geothermal fluids used for direct use purposes contain various chemical species which can be detrimental to conventional materials of construction. For this reason, the standard design practice is to isolate the geothermal fluid from the balance of the system through the use of a heat exchanger as illustrated in Figure 1 (ASHRAE, 1991). In the majority of applications, the plate and frame heat exchanger has been the design of choice for this duty. Plate and frame heat exchangers offer many advantages for geothermal applications including their availability in corrosion resistant materials (stainless steel) at reasonable cost. In addition, this design permits disassembly for cleaning or the addition of plates to accommodate increased heating loads. The units are very compact and efficient with heat transfer rates 3 to 10 times those of shell and tube exchangers (ASHRAE, 1991).

Rafferty, Kevin

1993-01-01

82

Heat exchangers  

International Nuclear Information System (INIS)

The tubes of a heat exchanger tube bank have a portion thereof formed in the shape of a helix, of effective radius equal to the tube radius and the space between two adjacent tubes, to tangentially contact the straight sections of the tubes immediately adjacent thereto and thereby provide support, maintain the spacing and account for differential thermal expansion thereof

1975-03-03

83

Heat exchangers  

International Nuclear Information System (INIS)

Description is given of a heat exchanger with exchange surfaces of preformed metal-sheets constituting at least one exchange bundle. A bundle comprises juxtaposed independent compartments, each of which comprising two superimposed preformed sheets and its respective manifolds for the inlet and outlet of a coolant. Substantially in parallel relationship to one surface of the respective compartment, said manifolds are mounted at the ends and on the opposed surfaces of the compartment, thus giving it, in cross-section, the shape of a Z with truncated arms. Since the sheets forming each compartments are of rectangular shape, the various juxtaposed independent compartments constitute an exchange-bundle of generally parallelepipedic shape, the manifolds being arranged in stepped fashion and defining those two sides of the parallelepiped inclined with respect to the axis of the latter. The heat-exchanger according to the invention can be used in particular in nuclear power stations, either mobile or not, e.g. of the PWR-type, and also in small-size installations

1974-01-01

84

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

DEFF Research Database (Denmark)

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 ExcelTM. 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.

Berning, Torsten

2011-01-01

85

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

International Nuclear Information System (INIS)

[en] 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

1996-01-01

86

Heat exchanger  

International Nuclear Information System (INIS)

A heat exchanger such as forms, for example, part of a power steam boiler is made up of a number of tubes that may be arranged in many different ways, and it is necessary that the tubes be properly supported. The means by which the tubes are secured must be as simple as possible so as to facilitate construction and must be able to continue to function effectively under the varying operating conditions to which the heat exchanger is subject. The arrangement described is designed to meet these requirements, in an improved way. The tubes are secured to a member extending past several tubes and abutment means are provided. At least some of the abutment means comprise two abutment pieces and a wedge secured to the supporting member, that acts on these pieces to maintain the engagement. (U.K.)

1975-01-01

87

Heat exchangers  

International Nuclear Information System (INIS)

A heat exchanging apparatus comprises an elongate chamber which is part filled with a heat transfer medium, and a pair of U-shaped pipes. The pipes are spaced from one another, but are generally mutually adjacent so that heat from a liquid flowing in one pipe can be transferred through a medium to the liquid in the other pipe. If one or other of the pipes ruptures the escaping liquid can be vented and will not intermix with the liquid in the other pipe. A level detector detects a rise in the level of the material in the chamber when a pipe ruptures and closes valves to prevent further loss of liquid. The apparatus is particularly suitable for use in the food industry or where one of the liquids is toxic or radioactive. (author)

1981-01-01

88

Corrosive resistant heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A corrosive and errosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is conveyed through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium.

Richlen, Scott L. (Annandale, VA)

1989-01-01

89

Performance Analysis of Spiral Tube Heat Exchanger  

Directory of Open Access Journals (Sweden)

Full Text Available In the present study, the performance of the spiral tube heat exchanger can be carried out. The heat exchanger consists of a shell and tube unit. Each coil is fabricated by bending a 12 mm diameter straight copper tube into a spiral coil tube of four turns. Cold water and hot oil are used as working fluids in shell side and tube side, respectively. The experiments are done at the cold water and hot oil mass flow rates ranging between 0.075 and 0.25 kg/s, and between 0.008 and 0.04 kg/s, respectively. The inlet temperatures of cold and hot water are between 29 and 37 °C, and between 70 and 56 °C, respectively. The cold water entering the heat exchanger at the shell inlet side and outer from the shell outside. The hot water enters the heat exchanger at the inner tube side and flows along the outside of the tube. The effects of the inlet conditions of both working fluids flowing through the test section on the heat transfer characteristics are discussed..

JAY J. BHAVSAR,; DR. V K. MATAWALA,; S.B.DIXIT

2013-01-01

90

Heat exchangers for industrial processes. Varmevekslere til industrielle processer  

Energy Technology Data Exchange (ETDEWEB)

The report describes a computer program for dimensioning shell and tube heat exchangers. The program is based on a model from VDI-Waermeatlas and compared with an earlier used program at Vesta LtD. The program is prepared for other types of heat exchangers. The program is completely menudriven and easy to use. The program can be run on every 100% IBM-compatible pc's. The comparison with the earlier used program shows in some cases a bad agreement. This disagreement is prelimary caused by the fact that the earlier used program is based on an imperial model, while this program is based on a theoretical and imperial model. The comparison with an example from VDI-Waermeatlas shows and deviation of 0.6% in the calculation of the heat transfer coefficient on the shell side of the heat exchanger. (au).

Elefsen, F.

1992-02-01

91

Heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger comparising a shell attached at its open end to one side of a tube sheet and a detachable head connected to the other side of said tube sheet. The head is divided into a first and second chamber in fluid communication with a nozzle inlet and nozzle outlet, respectively, formed in said tube sheet. A tube bundle is mounted within said shell and is provided with inlets and outlets formed in said tube sheet in communication with said first and second chambers, respectively.

Brackenbury, Phillip J. (Richland, WA)

1986-01-01

92

Design of intermediate heat exchanger for PFBR  

International Nuclear Information System (INIS)

Prototype fast breeder reactor (PFBR) is a sodium cooled 500 MWe pool type reactor. It has three heat transfer circuits viz. primary sodium circuit, secondary sodium circuit and water- steam circuit. The main vessel contains the pool of sodium and houses all the components of the primary sodium circuit. Two numbers of primary sodium pumps and four numbers of intermediate heat exchangers (IHX) have been provided. The nuclear heat generated in the core is transferred to secondary sodium in IHX by circulation of primary sodium. There are two secondary sodium circuits. Each circuit contains one sodium pump, one surge tank and four steam generators (in parallel) and is connected to two IHXs in the reactor. The secondary sodium circuits transfer the heat to water/steam in steam generators (SG). Super heated steam produced in the SGs is used to drive the turbo-alternator set to generate power. The IHX is a very important component of the reactor because it forms the boundary between radioactive primary sodium in the reactor pool and non-radioactive secondary sodium. The IHX is a counter flow shell-and-tube heat exchanger. The IHX is designed to meet the specified design requirements and constraints. This involves thermal, hydraulic, and structural design. In this paper, the design features, design conditions and design of IHX for PFBR are described. 4 figs., 3 tabs.

1996-01-01

93

High temperature heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

This book contains the proceedings from the XVII Symposium of the International Center for Heat and Mass Transfer on High Temperature Heat Exchangers, held August 1985 in Yugoslavia. Papers were presented under the following topics: High Temperature Heat Exchangers Development; Basic Problem in High Temperature Heat Exchangers; Heat Exchangers for High Temperature Recovery; and High Temperature Heat Exchangers for Future Power Plants and Industrial Process Application. Some of the papers' titles are: Future Development of High Temperature Heat Exchangers; Regenerative and Direct Contact High Temperature Heat Exchangers; Heat Exchangers for Heat Recovery; High Temeprature Heat Transfer Augmentation; and Development of a BOF Slag Granulating and Heat Recovering System.

Mori, Y.; Sheindlin, A.E.; Afgan, N.

1986-01-01

94

Heat exchangers  

International Nuclear Information System (INIS)

[en] This invention relates to a heat exchanger, more particularly intended, although not exclusively, for transferring the thermal power acquired by an initial fluid medium cooling the core assemblies of a nuclear reactor to another fluid medium isolated from the first, therefore having low activity and suitable them to generate steam in a separate generator. The invention applies particularly in the case where the first fluid medium or primary fluid is a liquid metal, generally sodium, used as coolant in a fast nuclear reactor, the second fluid medium or secondary fluid also being liquid sodium, flowing through tubes between two tube plates respectively to enter an intake manifold and an outlet manifold of the secondary sodium. These tubes are externally steeped in the primary sodium. The exchanger concerned comprises two tube plates fitted inside an external envelope crossed by a primary fluid. These two tube plates are joined by a bundle of tubes extending vertically over the major part of their length and through which a secondary fluid flows, these tubes being covered externally by the primary fluid exchanging heat with the secondary fluid through these tubes[fr] La presente invention est relative a un echangeur de chaleur, destine plus particulierement, quoique non exclusivement, a transferer la puissance thermique acquise par un premier milieu fluide assurant le refroidissement des assemblages du coeur d'un reacteur nucleaire, a un deuxieme milieu fluide isole du premier, donc de faible activite et apte a produire ensuite de la vapeur dans un generateur separe. L'invention s'applique plus specialement dans le cas ou le premier milieu fluide ou fluide primaire est un metal liquide generalement du sodium, utilise comme refrigerant dans un reacteur nucleaire a neutrons rapides, le deuxieme milieu fluide ou fluide secondaire etant egalement du sodium liquide, parcourant des tubes s'etendant entre deux plaques a tubes pour deboucher respectivement dans un collecteur d'entree et un collecteur de sortie du sodium secondaire, ces tubes etant baignes exterieurement par le sodium primaire. L'echangeur considere, comporte, montees a l'interieur d'une enveloppe externe traversee par un fluide primaire, deux plaques a tubes reunies par un faisceau de tubes s'etendant verticalement sur la majeure partie de leur longueur et parcourus par un fluide secondaire, ces tubes etant baignes exterieurement par le fluide primaire echangeant des calories avec le fluide secondaire a travers ces tubes

1976-01-01

95

Design of the intermediate heat exchanger for the high temperature gas-cooled reactor hydrogen cogeneration system, (1)  

International Nuclear Information System (INIS)

Japan Atomic Energy Agency (JAEA) has been carrying out design studies of the Gas Turbine High Temperature Reactor 300 for Cogeneration (GTHTR300C). One of the key components in the GTHTR300C is an intermediate heat exchanger (IHX). The IHX for the GTHTR300C is rated 170 MWt and designed on the basis of the shell and tube type IHX adopted in the High Temperature engineering Test Reactor (HTTR). As a conceptual design, we selected the heat exchanger tube size which is based on heat transfer calculation, designed conceptual structure, and evaluated the primary stress in design condition. By the results of this study, the technical feasibility of the large size shell and tube type IHX for the GTHTR300C was verified. (author)

2007-01-01

96

Online performance assessment of heat exchanger using artificial neural networks  

Directory of Open Access Journals (Sweden)

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.

C. Ahilan, S. Kumanan, N. Sivakumaran

2011-01-01

97

Heat pipe array heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

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.

Reimann, Robert C. (Lafayette, NY)

1987-08-25

98

Technical and economic evaluation of a solid-particle/air direct-contact heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A conceptual design of a solid-particle/air heat exchanger system is presented including a multistage fluidized-bed heat exchanger, solid-particle feeders and defeeders, and cyclones. The system is designed for 100/sup 0/C solid particles that heat air at 10 atm at a 100-MW heat rate. This type of heat exchanger could be part of a solar thermal central receiver system that uses solid particles as the heat transfer media. The technical and economic feasibilities of this system are evaluated. As an alternative to direct contact, a shell-and-tube heat exchanger is evaluated as well. The direct-contact system is technically feasible though additional development is needed in some areas. The annual levelized cost per unit of delivered thermal energy for a direct-contact system based on state-of-the-art technology is estimated to be $6.66/GJ. If reasonable assumptions are made as to technical progress resulting from future development activities, the cost drops to $2.30/GJ. The cost of a shell-and-tube heat exchanger for the same service is estimated to be $2.91/GJ.

Green, H.J.; Leboeuf, C.M.; Bohn, M.S.

1986-10-01

99

Study on Performance Evaluation of Oscillating Heat Pipe Heat Exchanger for Low Temperature Waste Heat Recovery  

Energy Technology Data Exchange (ETDEWEB)

Performance of heat exchanger was evaluated to heat exchanger using oscillating heat pipe for waste heat recovery of low temperature. Oscillating heat pipe used in this study was formed to the closed loop of serpentine shapes using copper tubes. Heat exchanger was formed to shell and tube type and composed of low finned tube. R-22 and R-141b were used to the working fluids of tube side and their charging ratio was 40%. and, water was used to the working fluid of shell side. As the experimental parameters, the inlet temperature difference of heating and cooling part of secondary fluid and the mass velocity of secondary fluid were used. The mass velocity of secondary fluid was changed from 90 kg/m{sup 2}s to 190 kg/m{sup 2}s. From the experimental results, heat recovery rate was linearly increased to the increment of the mass velocity of secondary fluid and the inlet temperature difference of secondary fluid. Finally, the performance of heat exchanger was evaluated by using {epsilon}-NTU method. It was found that NTU was about 1.5 when effectiveness was decided to 80%. 13 refs., 11 figs., 2 tabs.

Ahn, Young Tae [Samsung Electronics Co. Ltd., Suwon (Korea); Lee, Wook Hyun [LG Electronics Inc., Changwon (Korea); Kim, Jeung Hoon [Research Center for Ocean Industrial Development, Pukyong National University, Pusan (Korea); Kim, Jong Soo [Faculty of Mechanical Engineering, Pukyong National University, Pusan (Korea)

2001-05-01

100

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)

1990-01-01

 
 
 
 
101

Materials experience and selection for nuclear materials production reactor heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

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).

Marra, J.E.; Louthan, M.R. Jr.

1990-01-01

102

Materials experience and selection for nuclear materials production reactor heat exchangers  

International Nuclear Information System (INIS)

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 repositioned 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)

1990-01-01

103

Selection of the most suitable refrigerant for a shell and tube condenser  

Science.gov (United States)

A theoretical performance study on a shell and tube condenser with various refrigerant blends was conducted for various ratios proposed by other researchers in the literature. The theoretical results showed that all of the alternative refrigerants investigated in the analysis have a slightly lower convective heat transfer coefficient than their base refrigerants. The refrigerant mixture of R290/R600, R152a/R125/R32 and R32/R134a were found to be the most proper replacement refrigerant among the alternatives.

Dalkilic, A. S.; Mahian, O.; Wongwises, S.

2013-10-01

104

A Simple Tubesheet Layout Program for Heat Exchangers  

Directory of Open Access Journals (Sweden)

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.

S. Murali; Y. B. Rao

2008-01-01

105

Woven heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

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.

Piscitella, Roger R. (Idaho Falls, ID)

1987-01-01

106

Method and apparatus for efficient recovery of heat from hot gases that tend to foul heat exchanger tubes  

Energy Technology Data Exchange (ETDEWEB)

In recovering heat from a high temperature cracked hydrocarbon gas, a method is described of injecting a liquid wash into the tubes of a vertically oriented multitube shell-and-tube transfer line heat exchanger (TLE). The TLE comprises more than one heat exchange tube and a top tube sheet to prevent deposition of condensable components and coke which comprises introducing the liquid wash into a plenum chamber adjoining and on top of the shell side of the exchanger and defined by the top tube sheet of the exchanger, a horizontal distributor plate thereabove, an outer wall section of the shell of the exchanger therebetween and the wall portion of the tubes between the top tube sheet and the distributor plate. The distributor plate causes the liquid wash to overflow the plenum chamber through holes in the distributor plate and flow downwardly within the tubes with the cracked gas.

Oldweiler, M.E.

1986-09-30

107

Heat exchangers for cardioplegia systems: in vitro study of four different concepts.  

Science.gov (United States)

The aim of this work is the evaluation of four different heat exchangers used for myocardium during cardioplegic system in cardiac surgeries. Four types of shell and tube heat exchangers made of different exchange elements were constructed, as follows: stainless steel tubes, aluminium tubes, polypropylene hollow fiber, and bellows type. The evaluation was performed by in vitro tests of parameters such as heat transfer, pressure drop, and hemolysis tendency. The result has shown that all four systems tested were able to achieve the heat performance, and to offer low resistance to flow, and safety, as well as have low tendency to hemolysis. However, we can emphasize that the bellows type heat exchanger has a significant difference with regard to the other three types. PMID:12752210

Drummond, Mário; Novello, Waldyr Parorali; de Arruda, Antonio Celso Fonseca; Braile, Domingo Marcolino

2003-05-01

108

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)

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.

Austegard, Anders

1997-12-31

109

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.)

1982-01-01

110

Fouling in heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Subjects covered: introduction to heat exchanger fouling; basic fouling models; precipitation fouling; CaCO[sub 3] scaling; black liquor fouling; geothermal brine fouling; particulate fouling; chemical reaction fouling; fouling of enhanced surfaces - experimental results; fouling of enhanced surfaces - theory; chemical fouling mitigation; mechanical fouling mitigation; heat exchanger design for fouling conditions; fouling monitoring systems; cleaning of heat exchangers; and economic aspects of heat exchanger fouling.

1993-01-01

111

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

1996-01-01

112

Dynamic friction modelling in heat exchanger tube simulations  

Energy Technology Data Exchange (ETDEWEB)

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.

Tan, X.; Rogers, R.J. [Univ. of New Brunswick, Fredericton, New Brunswick (Canada). Dept. of Mechanical Engineering

1996-12-01

113

Multivariable optimal control of a heat exchanger network (HEN) with bypasses  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger is used in chemical plants to promote the energy exchange between a hot and a cold stream in order to minimize power consumption in the manufacturing process. This reduction in energy consumption is obtained by using several heat exchangers called a heat exchanger network (HEN). Most of the HEN applications in industrial plants use shell and tube heat exchangers. However, the stream outlet temperatures must be in a specified range or value, regardless of the heat exchanger type. This could be achieved by using an efficient control system. The most common control techniques for closed loop control on a heat exchanger network are the predictive control, the neural network and even the feed forward PID. The purpose of this study was to demonstrate the procedure of the design, as well as to exhibit the performance of this intermediate solution on the closed loop control of the heat exchanger network. The paper provided a brief introduction of a nonlinear heat exchanger model and its dynamics characteristics. The structure of the heat exchanger network was also presented. The application of LQR on the heat exchanger network was also discussed. The simulation results obtained with the dynamic decoupling and decentralized PID were presented. It was concluded that the proposed optimal control provides reasonable control performance. 12 refs., 2 tabs., 18 figs.

Delatore, F.; Cruz, J.J. [Sao Paulo Univ., Sao Paulo (Brazil); Leonardi, F.; Novazzi, L.F. [Centro Univ. da FEI, Sao Bernardo do Campo (Brazil)

2010-08-13

114

Heat exchange apparatus  

International Nuclear Information System (INIS)

The present invention relates to heat exchangers used for transferring heat from the gas cooled core of a nuclear reactor to a secondary medium during standby and emergency conditions. The construction of the heat exchanger described is such that there is a minimum of welds exposed to the reactor coolant, the parasitic heat loss during normal operation of the reactor is minimized and the welds and heat transfer tubes are easily inspectable. (UK).

1979-01-01

115

Microtube strip heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

During the last quarter, Doty Scientific, Inc. (DSI) continued to make progress on the microtube strip (MTS) heat exchanger. DSI completed a heat exchanger stress analysis of the ten-module heat exchanger bank; and, performed a shell-side flow inhomogeneity analysis of the three-module heat exchanger bank. The company produced 50 tubestrips using an in-house CNC milling machine and began pressing them onto tube arrays. DSI revised some of the tooling required to encapsulate a tube array and press tubestrips into the array to improve some of the prototype tooling. 2 refs., 4 figs.

Doty, F.D.

1991-07-08

116

Heat transfer in tube bundles of heat exchangers with flow baffles induced forced mixing  

International Nuclear Information System (INIS)

Thermal analysis of shell-and-tube heat exchangers is being investigated through geometric modeling of the unit configuration in addition to considering the heat transfer processes taking place within the tube bundle. The governing equations that characterize the heat transfer from the shell side fluid to the tube side fluid across the heat transfer tubewalls are indicated. The equations account for the heat transfer due to molecular conduction, turbulent thermal diffusion, and forced fluid mixing among various shell side fluid channels. The analysis, though general in principle, is being applied to the Clinch River Breeder Reactor Plant-Intermediate Heat Exchanger, which utilizes flow baffles appropriately designed for induced forced fluid mixing in the tube bundle. The results of the analysis are presented in terms of the fluid and tube wall temperature distributions of a non-baffled and baffled tube bundle geometry. The former case yields axial flow in the main bundle region while the latter is associated with axial/cross flow in the bundle. The radial components of the axial/cross flow yield the necessary fluid mixing that results in reducing the thermal unbalance among the heat transfer to the allowable limits. The effect of flow maldistribution, present on the tube or shell sides of the heat exchangers, in altering the temperature field of tube bundles is also noted

1976-12-05

117

Optimization of Heat Exchangers  

Energy Technology Data Exchange (ETDEWEB)

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.

Ivan Catton

2010-10-01

118

Active microchannel heat exchanger  

Science.gov (United States)

The present invention is an active microchannel heat exchanger with an active heat source and with microchannel architecture. The active 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.

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

2001-01-01

119

Advanced heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

This brief article describes the concept of compact heat exchangers and the advantages both financially and in improved energy efficiency terms associated with their utilisation. Examples including the highly novel printed circuit heat exchanger are given of several successful applications in process industry based on projects from the UK's research and demonstration programmes on energy efficiency. (UK)

Mercer, A. (Energy Technology Support Unit, Harwell (United Kingdom))

1994-03-01

120

Phase change heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger for a phase change material having a solid density greater than its liquid density, the heat exchanger is described comprising a container holding the phase change material, a tube surrounding the container to define an annular space there between, means for connecting the tube in fluid communication with a first source of heat exchange fluid to allow heat exchange fluid to flow through the annular space to exchange heat with the phase change material, and at least two divider walls extending between the tube and the container across the annular space to divide the annular space into at least a lower flow passageway for receiving heat exchange fluid from the first source at a temperature sufficient to initiate melting of the phase change material and an upper flow passageway for receiving heat exchange fluid from the lower flow passageway to flow in counter flow relationship with the heat exchange fluid flowing in the lower passageway so that the phase change material is melted from the bottom as it moves to a lower portion of the container to cause newly-formed liquid phase change material to be displaced to an upper portion of the container.

Longardner, R.L.; Longardner, W.J.

1993-06-22

 
 
 
 
121

Nuclear heat exchangers  

International Nuclear Information System (INIS)

[en] This paper presents general design features and characteristics of nuclear heat exchangers including nuclear steam generators. In particular, the heat exchangers in the pressurized light or heavy water reactor and the liquid metal fast breeder reactor plants, and their thermal and hydraulic characteristics are discussed in detail

1988-01-01

122

Plate heat exchanger; Plattvaermevaexlare  

Energy Technology Data Exchange (ETDEWEB)

The invention suggests a plate package where the end plates have eight openings for through-flow of the heat exchange fluid. By choosing which openings should be utilized, it is possible to connect two or more plates to a plate heat exchanger

Kaellrot, M.

1995-10-09

123

Heat exchanger system  

Energy Technology Data Exchange (ETDEWEB)

The heat exchanger system is used for gas-cooled high temperature reactors. The high-temperature primary gas passes over a nest of blind tubes and thereafter flows over the tubes of a plurality of counter-current heat-exchangers disposed about a jacket encasing the blind tubes. The cool working gas flows into the system via a header and then passes through the tubes of the counter-current heat-exchangers before passing into the blind tubes. The working gas is exhausted via insert tubes within the blind tubes. The maximum temperatures on the heat exchanger surfaces occur at the closed ends of the blind tubes. However, these parts are substantially stress free in normal operation. The heat exchanger system may be constructed to permit ready disassembly of the insert tubes for inspection and replacement purposes.

Weber, M.

1980-09-02

124

Tertiary heat exchanger  

International Nuclear Information System (INIS)

The invention deals with the improvement of a tertiary heat exchanger possessing a contact medium besides a heating and working medium. These kind of heat exchangers are used in sodium-cooled nuclear power plants. The contact medium used so far should be reploced by a metal granulate which is used in porous bulk of single grains of varying size. It is advantageous to use copper as granulate. (RW).

1977-01-01

125

Thermoelectric heat exchange element  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2007-08-14

126

Heat exchanger apparatus  

Energy Technology Data Exchange (ETDEWEB)

A vapor component of a gas mixture is separated by condensation and is recovered for further use. A solvent vapor mixed with inert gas is condensed in a multistage heat exchange system in a manner which utilizes a first refrigerant to condense a portion of the vapor in a first heat exchange device, a second refrigerant, typically cold inert gas, for condensing a further portion of the vapor in a second heat exchanger and a third heat exchange device wherein the liquid phase of the inert gas (i.e. cryogenic liquid) is supplied to provide a source of refrigeration. In this latter heat exchange device, the cryogenic liquid is introduced into a body of condensed vapor thereby chilling such condensed vapor and stirring the same to avoid freezing. Chilled, condensed vapor is removed from the latter heat exchange device and is returned as a reflux thereto to condense the vapor component of the gaseous mixture supplied thereto. A further portion of the chilled, condensed vapor is recirculated to the body of condensed vapor to assist the stirring of this body to avoid freezing of condensed vapor which is collected from the above heat exchange devices and is passed to a suitable storage facility.

Banerjee, R.

1984-04-24

127

Vacuum powered heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

In an internal combustion engine including an oil lubrication system, a liquid cooling system, and an improved air intake system is described. The improved air intake system comprises: a housing including a first opening in one end, which opening is open to the atmosphere and a second opening comprising an air outlet opening in the other end open to the air intake manifold of the engine, a heat exchanger positioned in the first opening. The heat exchanger consists of a series of coils positioned in the flow path of the atmospheric air as it enters the housing, the heat exchanger being fluidly connected to either the engine lubrication system or the cooling system to provide a warm heat source for the incoming air to the housing, acceleration means positioned in the housing downstream of the heat exchanger, the acceleration means comprising a honeycomb structure positioned across the air intake flow path. The honey-comb structure includes a multitude of honey combed mini-venturi cells through which the heated air flows in an accelerated mode, a removable air filter positioned between the heat exchanger and the acceleration means and a single opening provided in the housing through which the air filter can be passed and removed, and additional openings in the housing positioned downstream of the heat exchanger and upstream of the air filter, the additional openings including removable flaps for opening and closing the openings to control the temperature of the air flowing through the housing.

Ruffolo, R.F.

1986-06-24

128

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

129

Heat exchanger design handbook  

CERN Multimedia

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

Thulukkanam, Kuppan

2013-01-01

130

Maintenance of heat exchangers  

International Nuclear Information System (INIS)

A brief overview of failure indication, repair and maintenance methods of heat exchangers in nuclear power plants is presented. Two major techniques are applied for detecting failure in the heat exchanger: leak testing, erosion and wear inspection. Various water chemistry methods are shown for leakage identification. General repair methods depending on the type of failure are summarized, and some novel techniques are proposed. Thermal calculations are shown to be a useful method for heat exchanger maintenance and failure prevention. (R.P.) 2 figs.; 1 tab

1990-01-01

131

Vertical heat exchanger  

International Nuclear Information System (INIS)

The design is described in detail of a vertical heat exchanger with two separate vertical capillary tube bundles and with heating steam condensation in the inter-tube space of the tube bundles. The design features a number of advantages, such as: the heat exchanger allows the supply of condensate from a higher heating degree; the inner structure separates the top and the bottom tube bundles thus preventing the condensate from running down to the bottom bundle; the inner structure and the jacket form the inlet steam chamber from which the heating steam is evenly distributed to both tube bundles; the assembly of the heat exchanger is easy because the inner structure is welded in the jacket as a whole and the tube bundles are inserted from both sides. It is also advantageous that the condensate produced on the individual bundles can be separated and the condensate level in the collector can be controlled in service and discharged from the heat exchanger through the discharge pipe. The heat exchanger is usable for both conventional and nuclear power generation. (A.K.). 3 figs

1983-08-31

132

Fouling of heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

All aspects of heat exchanger fouling are considered, from the basic science of how surfaces become fouled to very practical ways of mitigating the problem and from mathematical modeling of different fouling mechanisms to practical methods of heat exchanger cleaning. The problems that restrict the efficient operation of equipment are described and the costs, some of them hidden costs, that are associated with the fouling of heat exchangers are discussed. Some simple concepts and models of the fouling processes are presented as part of the introduction to the subject. Advice on the selection, design, installation and commissioning of heat exchangers to minimize fouling is given. A large part of the test is devoted to the use of chemical and other additives to reduce or eliminate the problem of fouling. Another large section is designed to give information on both on-line and off-line cleaning of heat exchangers. One of the difficulties faced by designers and operators of heat exchangers is anticipating the likely extent of fouling problems to be encountered with different flow streams. Another large section addresses the question and describes methods that have been used in attempting to define fouling potential. The book concludes with a chapter on how fouling information can be obtained using plant data, field tests and laboratory studies

Bott, T.R. [School of Chemical Engineering, University of Birmingham, Birmingham (United Kingdom)

1995-04-01

133

Radial flow heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

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.

Valenzuela, Javier (Hanover, NH)

2001-01-01

134

Spiraflow heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Although different in their design and mode of functioning Spiraflow heat exchangers combine the positive properties of other systems. They consist of several corrugated-surface tubes which being of the coaxially telescoping type are forming annular ducts for the counterflow heating or cooling of the media they carry. With the widths of apertures, the resistances and heat transmission changing as the tubes are twisted Spiraflow heat exchangers can be adapted to any process the most optimum way possible. Access is given to different types such as 1) the Spiraflow Multichannel with 4 to 8 coaxial ducts, 2) the Spiraflow Monochannel with three annular ducts, 3) the Spiraflow Multitube consisting of several tubes sheathed by one, and 4) the Spiraflow Monotube consisting of one sheathed tube. The paper concludes with describing the heat exchanger's advantages and practical uses.

1988-02-01

135

The right exchange[Plate heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

This article focuses on recent developments in plate heat exchangers which will increase the users choice in the industrial, chemical, petrochemical and refrigeration markets. Gasketed plate heat exchangers and their advantages and limitations are described, and components of the gasketed plate heat exchangers, a typical plate, and a typical gasket/plate assembly section are illustrated. The advantages of using welded pair gasketed plate heat exchangers in terms of flexibility, construction, and operation are discussed along with the combination of welded pairs and PTFE (polytetrafluoroethylene) lined rings for allowing the use of plate heat exchangers for solvents, acids and hydrocarbons.

Kumar, H. [APV Heat Exchanger Product Group (United States)

1999-09-01

136

Tube vibration in industrial size test heat exchanger  

International Nuclear Information System (INIS)

[en] 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

1980-01-01

137

Microtube strip heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

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.

Doty, F.D.

1992-07-09

138

Heat exchanger restart evaluation  

International Nuclear Information System (INIS)

[en] 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 4A 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 identified tube. The leaking tube was removed and examined metallurgically to determine 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 summary herein

1992-01-01

139

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

1992-01-01

140

Scraped surface heat exchangers.  

Science.gov (United States)

Scraped surface heat exchangers (SSHEs) are commonly used in the food, chemical, and pharmaceutical industries for heat transfer, crystallization, and other continuous processes. They are ideally suited for products that are viscous, sticky, that contain particulate matter, or that need some degree of crystallization. Since these characteristics describe a vast majority of processed foods, SSHEs are especially suited for pumpable food products. During operation, the product is brought in contact with a heat transfer surface that is rapidly and continuously scraped, thereby exposing the surface to the passage of untreated product. In addition to maintaining high and uniform heat exchange, the scraper blades also provide simultaneous mixing and agitation. Heat exchange for sticky and viscous foods such as heavy salad dressings, margarine, chocolate, peanut butter, fondant, ice cream, and shortenings is possible only by using SSHEs. High heat transfer coefficients are achieved because the boundary layer is continuously replaced by fresh material. Moreover, the product is in contact with the heating surface for only a few seconds and high temperature gradients can be used without the danger of causing undesirable reactions. SSHEs are versatile in the use of heat transfer medium and the various unit operations that can be carried out simultaneously. This article critically reviews the current understanding of the operations and applications of SSHEs. PMID:16527753

Rao, Chetan S; Hartel, Richard W

2006-01-01

 
 
 
 
141

Guide to compact heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

This Good Practice Guide is concerned with compact heat exchangers and their application in the UK process industries. The overall objective is to increase awareness of compact heat exchangers within industry. Its specific aims are to provide information on: the available types of compact heat exchangers, the potential benefits of compact heat exchangers and the application of compact heat exchangers within the UK process industries. (author)

1994-01-01

142

Heat exchangers modelling and simulation using the F correction factor method and ?-P-R-NTC method  

International Nuclear Information System (INIS)

In this paper there are presented comparatively the mathematical model, the calculation algorithm and the results obtained with the program that simulates the stationary and transient regimes of the shell-and-tube heat exchangers based on the method of correction factor F and the ?-P-R-NTC method. The program is realized by means of Microsoft Visual C++ compiler and can be applied to the thermal calculation of the heat exchangers with complex flow schemes. It is based on diagrams taken from literature. The working fluid of the modeled equipment which can be initialized in this program are light water and heavy water in liquid phase. The program can be up-graded by means of specific correction charts and operating fluid thermo-physics as well as thermodynamic properties library. This program is a fast and reliable tool in designing and verification of heat exchangers

2006-01-01

143

Thin film heat exchanger  

International Nuclear Information System (INIS)

[en] The description is given of a heat exchanger between a first 'hot' fluid and a second fluid to be heated, of the type comprising at least one heat exchange wall separating the fluids and through which heat is exchanged. The characteristic of this exchanger is that the wall which includes an upper end is a cyclindrical area of which the generating lines are vertical and the straight section is composed of a regular succession of undulations alternately marking peaks of convex waves and peaks of concave waves and that the exchanger includes facilities for introducing the second fluid in the upper end near the convex wave peaks of the face of the wall turned towards the second fluid[fr] On decrit un echangeur de chaleur entre un premier fluide dit 'chaud' et un deuxieme fluide a chauffer du type comportant au moins une paroi d'echange separant les fluides et a travers laquelle s'effectue un echange de calories. Il est caracterise en ce que la paroi qui comporte une extremite superieure est une surface cylindrique dont les generatrices sont verticales et dont la section droite est constituee par une succession reguliere d'ondulations definissant alternativement des sommets d'ondes convexes et des sommets d'ondes concaves, et en ce que l'echangeur comprend des moyens pour introduire le deuxieme fluide a l'extremite superieure au voisinage des sommets d'ondes convexes de la face de la paroi tournee vers le deuxieme fluide

1976-01-01

144

Microtube strip heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

This progress report is for the September--October 1991 quarter. 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.

Doty, F.D.

1991-10-16

145

Lightweight, compact heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger is described comprising: tubes defining first flow paths; pairs of generally C-shaped bars spacing tubes apart from adjacent tubes, the bars extending generally perpendicular to tubes and each pair of bars defining a second flow paths; an extended surface heat transfer element between each pair of bars; an integral lanced tab formed at each end of the bars, each tab folded over itself toward the heat exchanger center and capturing a portion of the extended surface heat transfer element between itself and the bar; side plates on each side of the heat exchanger, the side plate spaced from one of the tubes by a pair of bars; means for securing the tubes, bars, extended surface heat transfer elements and side plates together; and manifold means, sealingly attached to the tube ends for distributing a working fluid into first flow paths at one end of the tubes and for selecting the working fluid at the opposite end of the tubes.

Kredo, T.A.

1987-07-21

146

Microtube strip heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

During the last quarter, Doty Scientific, Inc. (DSI) continued to make progress on the microtube strip (MTS) heat exchangers. The team has begun a heat exchanger stress analysis, however they have been concentrating the bulk of their analytical energies on a CFD model to determine the location and magnitude of shell-side flow maldistribution which decreases heat exchanger effectiveness. DSI received 120 fineblanked tubestrips from Southern Fineblanking (SFB) for manufacturing process development. Both SFB and NIST provided inspection reports of the tubestrips. DSI completed the tooling required to encapsulate a tube array and press tubestrips on the array. Pressing the tubestrips on tube arrays showed design deficiencies both in the tubestrip design and the tooling design. DSI has a number of revisions in process to correct these deficiencies. The research effort has identified a more economical fusible alloy for encapsulating the tube array, and determined the parameters required to successfully encapsulate the tube array with the new alloy. A more compact MTS heat exchanger bank was designed. 1 ref., 4 figs.

Doty, F.D.

1991-04-02

147

Heat exchanger vibration  

International Nuclear Information System (INIS)

The heat exchangers of various types are common items of plant in the generation and transmission of electricity. The amount of attention given to the flow-induced vibrations of heat exchangers by designers is usually related to the operational history of similar items of plant. Consequently, if a particular design procedure yields items of plant which behave in a satisfactory manner during their operational life, there is little incentive to improve or refine the design procedure. On the other hand, failures of heat exchangers clearly indicate deficiencies in the design procedures or in the data available to the designer. When such failures are attributable to flow-induced vibrations, the identification of the mechanisms involved is a prime importance. Ideally, basic research work provides the background understanding and the techniques necessary to be able to identify the important mechanisms. In practice, the investigation of a flow-induced vibration problem may identify the presence of mechanisms but may not be able to quantify their effects adequately. In these circumstances the need for additional work is established and the objectives of the research programme emerge. The purpose of this paper is to outline the background to the current research programme at C.E.R.L. on heat exchanger vibration

1977-01-01

148

Heat exchange panel  

Energy Technology Data Exchange (ETDEWEB)

A heat exchange panel having a desired system of internal tubular passageways is described, wherein the internal passageways include opposed headers connected by connecting portions of said passageways extending therebetween. The headers are designed to provide uniform fluid distribution and to enable efficient drainage of fluid from the unit, including any entrapped gases.

Kleine, C.A.; Middleton, V.L.

1980-11-25

149

Fireplace heat exchanger unit  

Energy Technology Data Exchange (ETDEWEB)

A fireplace heat exchanger unit including a forward section disposed outside of the fireplace and a rearward section disposed within the fireplace are described. The forward section provides upper air inlet openings for admitting cool air into an air inlet chamber and a pair of lower air outlet openings having electric blowers for discharging warmed air from air outlet chambers housing electric blowers. The rearward section is generally u-shaped and provides a duct connection between the inlet and outlet chambers. It is disposed about the heat source and the duct connection provides air heating chambers to warm the air during passage from the inlet to the outlet chambers.

Livesay, K.

1980-11-04

150

Serpentine heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a furnace having a burner means for providing hot products of combustion, and an air flow means for circulating conditioned air, a heat exchanger for transferring heat from products of combustion to conditioned air. The heat exchanger comprises first and second matched clamshell plates assembled together. The plates connected at their respective edges by a sealing means for providing a seal thereat, each the plate having an internal surface defining a depression. The depressions together defining a serpentine passageway, an entrance and exhaust ported formed in the passageway. The surfaces including elongated ribs for obstructing fluid flow adjacent the exhaust portal and for directing fluid flow to under-utilized portions in the passageway.

Tomlinson, R.S.

1991-01-08

151

Dirty water heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger is described for use with a burner which produces hot gases and consists of: a cylindrical furnace duct having a first end connected to the burner for receipt of the hot gases and an open second end, the furnace duct defining a heater chamber therein; the furnace duct including a spiral liquid heating path surrounding at least a part of the heater chamber, the spiral path having a liquid inlet and a liquid outlet; an exhaust tube spaced apart from and surrounding at least a portion of the length of the furnace duct to define an exhaust gap therebetween, the exhaust trube having first and second ends, the second exhaust tube end being closed and surrounding the second furnace end to direct hot gases from the heater chamber, past the furnace duct second end and into the exhaust gap, the first exhaust tube end having an exhaust gas outlet, whereby the hot gases make a double pass and the heated liquid makes a single pass through the heat exchanger; means for mounting the furnace duct and the exhaust tube to one another, the mounting means securing the furnace duct to the exhaust tube at no more than one axial position to accommodate differential expansion between the furnace duct and the exhaust tube; a stationary mount secured to the first furnace duct end and a sliding support secured to the second exhaust tube end to accommodate differential axial expansion and contraction of the heat exchanger; and a slip joint mounting means allowing relative axial movement between the furnace duct and the exhaust tube, including radially oriented and axially extending spacer plates secured to one of the furnace duct and exhaust tube; and means for supporting the heat exchanger in a chosen position.

Urbani, W.G.

1986-04-29

152

Improvements to heat exchangers  

International Nuclear Information System (INIS)

[en] The heat exchanger presented consists of a chamber designed so that heating fluid passes through it over tubes carrying fluid which removes heat from the heating fluid. Generally speaking the heating fluid flows in the chamber downwards to the level of lateral holes through which it leaves the chamber or upwards from the level of lateral holes through which it enters, this level corresponding in the chamber to the top of a heating fluid mass cooled by the heat removal fluid. Partition system are foreseen in the heating fluid mass, so arranged as to define a passage through which heating fluid rises by differential thermal effect from the lowest region to that of the inlet and oulet holes. This system applies especially to exchangers associated with a liquid sodium-cooled reactor[fr] On presente un echangeur de chaleur comprenant une enceinte agencee pour que du fluide chauffant la traverse en balayant des tubes traverses par du fluide qui preleve de la chaleur sur le fluide chauffant. Le fluide chauffant circule d'une maniere generale, dans l'enceinte, de haut en bas vers le niveau d'orifices lateraux par lesquels le fluide chauffant sort de l'enceinte ou de bas en haut a partir du niveau d'orifices lateraux par lesquels le fluide chauffant entre dans l'enceinte, ce niveau delimitant dans l'enceinte le haut d'une masse de fluide chauffant refroidie par le fluide de prelevement de chaleur. Il est prevu, dans la masse de fluide chauffant, des moyens de cloisonnement disposes de maniere a definir un passage dans lequel du fluide chauffant monte, par effet thermique differentiel, de la region la plus basse jusqu'au voisinage des orifices, d'entree ou de sortie. Ceci s'applique particulierement aux echangeurs associes a un reacteur a refroidissement par sodium liquide

1974-08-23

153

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

International Nuclear Information System (INIS)

[en] 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.

2012-01-01

154

Vapor/Liquid Interaction and Entrainment in Shell-and-Tube Evaporators.  

Science.gov (United States)

The problem of vapor/liquid interaction and entrainment in shell-and-tube evaporators is analyzed. Attention is focused primarily on the horizontal tube falling film evaporators, which have been proposed for use in Ocean Thermal Energy Conversion (OTEC) p...

D. Yung J. J. Lorenz E. N. Ganic

1978-01-01

155

Heat exchanger-accumulator  

Energy Technology Data Exchange (ETDEWEB)

What is disclosed is a heat exchanger-accumulator for vaporizing a refrigerant or the like, characterized by an upright pressure vessel having a top, bottom and side walls; an inlet conduit eccentrically and sealingly penetrating through the top; a tubular overflow chamber disposed within the vessel and sealingly connected with the bottom so as to define an annular outer volumetric chamber for receiving refrigerant; a heat transfer coil disposed in the outer volumetric chamber for vaporizing the liquid refrigerant that accumulates there; the heat transfer coil defining a passageway for circulating an externally supplied heat exchange fluid; transferring heat efficiently from the fluid; and freely allowing vaporized refrigerant to escape upwardly from the liquid refrigerant; and a refrigerant discharge conduit penetrating sealingly through the top and traversing substantially the length of the pressurized vessel downwardly and upwardly such that its inlet is near the top of the pressurized vessel so as to provide a means for transporting refrigerant vapor from the vessel. The refrigerant discharge conduit has metering orifices, or passageways, penetrating laterally through its walls near the bottom, communicating respectively interiorly and exteriorly of the overflow chamber for controllably carrying small amounts of liquid refrigerant and oil to the effluent stream of refrigerant gas.

Ecker, Amir L. (Dallas, TX)

1980-01-01

156

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

Science.gov (United States)

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 Bi0.5Sb1.5Te3/Ni provides a promising solution. The Bi0.5Sb1.5Te3/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/m2K and a volume power density of 10?kW/m3 using low-grade heat sources below 100°C. The Bi0.5Sb1.5Te3/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.

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

2013-01-01

157

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

Science.gov (United States)

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 Bi0.5Sb1.5Te3/Ni provides a promising solution. The Bi0.5Sb1.5Te3/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 Bi0.5Sb1.5Te3/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

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

2013-03-20

158

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

UK PubMed Central (United Kingdom)

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 Bi0.5Sb1.5Te3/Ni provides a promising solution. The Bi0.5Sb1.5Te3/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 Bi0.5Sb1.5Te3/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.

Takahashi K; Kanno T; Sakai A; Tamaki H; Kusada H; Yamada Y

2013-03-01

159

Fireplace heat exchanger assembly  

Energy Technology Data Exchange (ETDEWEB)

A fireplace heat exchanger assembly is claimed having a conduit that includes a first passage communicating with an air inlet located outwardly of a fireplace and extending rearwardly across the top of the fireplace, and a second passage communicating with the first passage at the rear of the fireplace and extending forwardly across the top of the fireplace for communication with an air outlet located outwardly of the fireplace. A blower introduces air into the air inlet, passes the air through the first and second passages, and discharges the air through the air outlet. More particularly, the conduit includes a heat exchanger box of relatively smaller height than width and length, the box being provided with laterally spaced and enclosed slots therethrough to provide the first passage between the slots, and to provide a pair of second passages laterally outward of the slots, the slots terminating in spaced relation to the rear of the box to place the first and second passages in communication. In one embodiment, the heat exchanger box has angularly related box portions through which the enclosed slots extend, so that the first and second passages are disposed at an angle to the vertical at the rear of the fireplace, and the transverse passage interconnects the first and second passages at the bottom, rear of the fireplace. Further, the conduit includes a duct frame disposed externally at the top and sides of the fireplace through which the first and second passages communicate respectively with the air inlet and air outlet.

Pauley, E. E.

1980-02-12

160

Reduction of pumping energy losses in district heating and cooling systems. Final report  

Energy Technology Data Exchange (ETDEWEB)

This project was designed to find effective surfactant friction reducing additives for use in district heating systems with temperatures of 50 to 90{degrees}C and effective additives fore district cooling systems with temperatures of 5 to 15{degrees}C. Heat transfer measurements in conventional shell and tube heat exchangers and in plate heat exchangers were also carried out to see how seriously these surfactant drag reducing additives reduce heat transfer coefficients.

Zakin, J.L.; Christensen, R.N.

1992-10-01

 
 
 
 
161

Reduction of pumping energy losses in district heating and cooling systems  

Energy Technology Data Exchange (ETDEWEB)

This project was designed to find effective surfactant friction reducing additives for use in district heating systems with temperatures of 50 to 90[degrees]C and effective additives fore district cooling systems with temperatures of 5 to 15[degrees]C. Heat transfer measurements in conventional shell and tube heat exchangers and in plate heat exchangers were also carried out to see how seriously these surfactant drag reducing additives reduce heat transfer coefficients.

Zakin, J.L.; Christensen, R.N.

1992-10-01

162

Random excitation of heat exchanger tubes by cross-flows  

International Nuclear Information System (INIS)

[en] For designing shell-and-tube heat exchangers against flow-induced vibration, a reasonable assessment of tube response to the random excitation by the crossflow is required. Resulting tube vibration amplitudes will not, usually, lead to failures on a short term basis. However, they can produce a progressive damage at the supports through fretting wear or fatigue. A considerable amount of experimental and theoretical work was already reported in the open literature, concerning flow-induced vibration in tube arrays. Nevertheless it is generally agreed that design oriented information on random excitation still remains insufficiently documented. This is largely because general interest was, at first, focused on fluidelastic instability and periodic wake shedding mechanisms, which can lead to catastrophic tube failures. This paper reviews information on this topics, gained at CEA Saclay during the past decade from several experimental programs. This includes tests performed in single phase flow (both air and water) and in two-phase flow (air-water and steam-water)

1988-12-02

163

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 experimetnal quantities.

1985-01-01

164

Heat exchanger fouling  

Energy Technology Data Exchange (ETDEWEB)

The phenomenon of fouling in heat exchangers were described, with specific reference to studies underway in the Department of Chemical Engineering at the University of British Columbia. Studies at UBC cover five different types of fouling, i. e., particulate fouling from suspension, crystallization fouling from solution, chemical reaction fouling by deposit formation at the heat transfer surface, corrosion fouling due to accumulation of corrosion products at the heat transfer surface, and biofouling due to attachment of microorganisms to the surface. The deposition process for all forms of fouling under study involves a transport step in series with deposit attachment to the surface. New models for the deposit attachment are under development. The fouling of organic streams under oxygenated and non-oxidative conditions is also under study, with special attention to asphaltenes in the fouling of crude oils.

Epstein, N.

1996-11-01

165

High power heat pipe heat exchanger development  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of a recently completed SBIR Phase 2 program by Thermacore, Inc. to develop a 350kW heat pipe radiator for the M109 A6 Howitzer engine cooling. After a brief discussion of operating principles and unique advantages of heat pipe heat exchangers, the paper focuses on the development of high power heat pipe heat exchangers. Design and manufacturing issues associated with high power heat pipe heat exchangers, such as non-uniform heat load distribution, redundancy/damage resistance, and seals between the two fluid streams, are addressed. Test results of segment and full scale heat pipe radiators are presented. Heat pipe heat exchanger applications, including the potential applications in the turbine industry and the food and pharmaceutical industry, are discussed.

Fale, J.E.; Zuo, Z.J.; Gernert, N.J.; Goryca, M.L.

1998-07-01

166

Effectiveness-N sub TU relationships for the design and performance evaluation of two-stream heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Data item ESDU 85042, Heat Transfer Sub-Series, gives equations and a large number of curves derived from them to allow design or performance evaluation of shell-and-tube heat exchangers. The curves cover co-current and countercurrent flow and various numbers of shells and of tube side passes. Also shown on the curves are the locus of designs for which a temperature cross may occur and the locus or 95 percent heat transfer effectiveness which indicates the region of uneconomic design. The method assumes a linear temperature/enthalpy relationship (constant specific heat capacity) for both streams. It applies to boiling or condensing flow of a single component with no temperature change, or boiling and condensing flow of a mixture that is always two phase. It excludes conditions in which transition from single to two-phase flow occurs. Worked examples show the application of the method.

1985-12-01

167

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

1991-01-01

168

The Design of Heat Exchangers  

Directory of Open Access Journals (Sweden)

Full Text Available A relation between heat transferred and energy loss, for turbulent flow. In different tube arrangements, is made. The conditions are determined which decide the dimensions and velocities for a heat exchanger. Also, a reference to the economic dimensioning of heat exchangers is presented. In this study, the conditions which a heat exchanger must satisfy represent the best balance between the amounts of material employed. The investigation is restricted to the case of turbulent flow.

Arturo Reyes-León; Miguel Toledo Velázquez; Pedro Quinto-Diez; Florencio Sánchez-Silva; Juan Abugaber-Francis; Celerino Reséndiz-Rosas

2011-01-01

169

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.

1991-01-01

170

Plate heat exchanger  

International Nuclear Information System (INIS)

In a plate heat exchanger required to handle corrosive, toxic or radioactive fluids, wherein each plate has a peripheral recess or like formation adapted for receiving an elastomeric gasket, the plates are welded together in pairs by the method comprising the steps of inserting into the gasket recess of a first plate of said pair a metal packing piece and welding the second place (e.g. by a laser or electron beam weld running along the base of the recess) superimposing a second plate on to the first in contact with the packing piece and welding the second plate to the packing piece (e.g. by a laser or electron beam weld). The packing piece may be of hollow or solid cross section and is preferably of the same material (e.g. titanium or stainless steel) as the plates. In use a service fluid in heat exchange with the said corrosive etc. fluid is confined by peripheral and normally elastomeric gaskets. (author)

1982-01-01

171

Cyclone heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The study discusses cyclones situated in a preheater tower above a cement kiln. This preheater insures the thermal preparation of the material by a conter-flow heat exchange between the stream of cold material descending towards the kiln and the hot gaz drawn up towards the top of the tower by fans. The purpose is to reduce the energy consumption in the preheater tower. Energy can be saved by diminishing the power consumed by fans and by a better use of the heat brought by the gas. The efficiency of the thermal exchange is affected by the separation efficiency of the cyclones. However there is a lack of information about internal working parameters of these separators (separation efficiency, pressure drop, retention time of the material in the cyclones, etc...) since a suitable method of investigation was not available. An experimental method has been perfected, using radioactive tracers in order to investigate these parameters. A computer programme has been designed and evaluated by the experimental data. This programme has been used to optimise the cyclone geometry for a better separation efficiency and a lower pressure drop. An economic assessment shows that the profit is too small to justify alteration of a plant already working. But improvement of cyclones geometry shape with the help of the computer programme can be considered for future fittings.

Margrita, M.; Santos Cottin, M.; Pailhes, M.

1984-01-01

172

Tubular heat exchanger  

International Nuclear Information System (INIS)

[en] The invention concerns a heat exchanger of which the tubes, placed in a long casing, cross the casing cover in a sealed manner. These tubes are fixed to the tube plate forming this cover or to the branch tubes it comprises by means of compression joints. These joints make it possible to do away with welds that are sources of defects and to improve the operational safety of the apparatus. An advantageous form of the heat exchanger under the invention includes a manifold for each thermal exchange fluid, and one end of each tube is connected to this manifold by a pipe that is itself connected to the tube by a threaded connection. The latter provides for easy disconnection of the pipe in order to introduce a probe for inspecting the state of the tubes[fr] L'invention concerne un echangeur de chaleur dont les tubes, disposes dans une enveloppe allongee, traversent de facon etanche le couvercle de l'enveloppe. Ces tubes sont fixes a la plaque tubulaire constituant ledit couvercle, ou aux tubes de branchement qu'elle comporte, a l'aide de raccords a compression. Ces raccords permettent de supprimer les soudures qui constituent des sources de defauts et d'ameliorer la surete de fonctionnement de l'appareil. Une forme avantageuse de l'echangeur de chaleur suivant l'invention comprend un collecteur pour chaque fluide d'echange thermique, et une extremite de chaque tube est reliee a ce collecteur par un conduit lui-meme relie au tube par un raccord filete. Ce dernier permet un demontage aise du conduit pour l'introduction d'une sonde permettant de controler l'etat des tubes

1975-08-20

173

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2007-04-05

174

Model optimizes exchanger cleaning  

Energy Technology Data Exchange (ETDEWEB)

There are many simple models about fouling in the literature that calculate the optimum period for heat exchanger operation. Because of the assumptions and simplifications they contain, these models always yield, and often incorrectly, an optimum point. However, a more rigorous analysis indicates that the trend of fouling costs (which we try to minimize) can be increasing or decreasing, and certain conditions must be achieved for the existence of that optimum. This analysis applies to shell-and-tube heat exchangers in a crude oil preheat train, but it can be made suitable for any case with adequate changes.

Casado, E. (Centromin Peru' S.A., Lima (PE))

1990-08-01

175

Heat exchanger bypass test report  

International Nuclear Information System (INIS)

This test report documents the results that were obtained while conducting the test procedure which bypassed the heat exchangers in the HC-21C sludge stabilization process. The test was performed on November 15, 1994 using WHC-SD-CP-TC-031, ''Heat Exchanger Bypass Test Procedure.'' The primary objective of the test procedure was to determine if the heat exchangers were contributing to condensation of moisture in the off-gas line. This condensation was observed in the rotameters. Also, a secondary objective was to determine if temperatures at the rotameters would be too high and damage them or make them inaccurate without the heat exchangers in place

1995-01-01

176

Tube bundle heat exchanger  

International Nuclear Information System (INIS)

The heat exchanger consists of tube bundles mounted in parallel. Each bundle consists of a jacket in which tubes for a first coolant are mounted. Straight tubes are connected with their open ends to tube plates which, in turn, are connected to the jacket provided with the inlet and outlet for a second coolant. This passes between the outer surfaces of straight tubes and the inner jacket surface. Spacers are inserted between the tube bundles, this along the whole length of the bundles. The second coolant enters one tube plate through the open ends of inlet tubes. It leaves through the other tube plate of the respective bundle, through the open ends of the outlet tubes. The other open ends of the inlet and/or outlet tubes are inserted in auxiliary tube plates mounted in the jacket on both sides of the tube bundles. (H.S.)

1980-01-01

177

Total counterflow heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A total counterflow heat exchanger is described comprising: a shell of generally cylindrical shape open at a first end and a second end; a first end cap at the first end of the interior chamber; a second end cap at the second end of the interior chamber opposing the first end cap and extending radially inward from the periphery of the interior chamber perpendicular to the surface of the cylindrical portion of the shell and connected thereto; a first partition having a first end edge, an opposing second end edge, and an outer longitudinal edge, a second partition having a first end edge, an opposing second end edge, an outer longitudinal edge, and an opposing inner longitudinal edge; a third partition having a first end edge, an opposing second end edge, an outer longitudinal edge and an opposing inner longitudinal edge, and a serpentine tube spatially situated within and extending through the serpentine channel.

Christianson, P.O.; Mc Donald, J.M.

1987-11-17

178

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

Energy Technology Data Exchange (ETDEWEB)

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.

Duane Spencer; Kevin McCoy

2010-02-02

179

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.

2010-01-01

180

Designing heat exchangers for NPP  

International Nuclear Information System (INIS)

The bases for designing powerful heat exchangers for NPPs with sodium and gas coolants are delivered. The design features, methods of calculation and experimental development of heat exchangers with non-uniform longitudinal-cross coolant flow in a piping beam and methods of operating conditions determination are considered. 133 refs.; 171 figs.; 23 tabs

1988-01-01

 
 
 
 
181

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

Science.gov (United States)

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.

Grabenstein, V.; Kabelac, S.

2012-11-01

182

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

International Nuclear Information System (INIS)

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.

2012-11-26

183

Thermodynamics and heat exchange devices  

Energy Technology Data Exchange (ETDEWEB)

This paper reviews research efforts in the area of thermodynamic irreversibility of heat exchange components and systems, as well as, their design based on the minimization of the generation of entropy. The examination initially focusses upon the fundamental mechanisms responsible for the generation of entropy in heat and fluid flows and upon design compromises made to establish an equilibrium between the irreversibility of the fluid flow. The applications were chosen with reference to the field of heat exchange mechanisms and heat exchanger design (e.g. power plant components: reheaters, expanders, regenerators, coolers, compressors).

Bejan, A. (Duke Univ., Durham, NC (USA). Dept. of Mechanical Engineering and Material Science)

1988-01-01

184

Heat exchange methods and apparatus  

Energy Technology Data Exchange (ETDEWEB)

A vapor component of a gas mixture is separated by condensation and is recovered for further use. A solvent vapor mixed with inert gas is condensed in a multistage heat exchange system in a manner which utilizes a first refrigerant to condense a portion of the vapor in a first heat exchange device, a second refrigerant, typically cold inert gas, for condensing a further portion of the vapor in a second heat exchanger and a third heat exchange device wherein the liquid phase of the inert gas (i.e. cryogenic liquid) is supplied to provide a source of refrigeration. In this latter heat exchange device, the cryogenic liquid is introduced into a body of condensed vapor thereby chilling such condensed vapor and stirring the same to avoid freezing. Chilled, condensed vapor is removed from the latter heat exchange device and is returned as a reflux thereto to condense the vapor component of the gaseous mixture supplied thereto. A further portion of the chilled, condensed vapor is recirculated to the body of condensed vapor to assist the stirring of this body to avoid freezing of condensed vapor which is collected from the above heat exchange devices and is passed to a suitable storage facility.

Banerjee, R.

1985-11-12

185

Laser-heated heat-exchanger thruster  

Energy Technology Data Exchange (ETDEWEB)

A hydrogen-fuelled laser-heated thruster can produce a specific impulse of 500--800 seconds -- sufficient to reach Earth orbit with plausible single-stage mass ratios -- at exhaust temperatures between 1000 K and 2000 K. At these low temperatures, a solid heat exchanger can be both cheap and efficient. A heat-exchanger-based thruster has a fundamental advantage over other laser-heated engines in that it is omnivorous -- any laser wavelength or pulse format is acceptable. We present some options for vehicle and launch-system design and estimate their performance. 13 refs., 8 figs.

Kare, J.

1991-04-01

186

Fouling of heat exchanger surfaces  

Energy Technology Data Exchange (ETDEWEB)

45 papers are presented under the session headings: microbial fouling; chemical reaction fouling; gas-side fouling of heat exchanger surfaces; particulate fouling; advanced cycle fouling; gas-side fouling as a result of impurities in fossil fuels; precipitate and freezing fouling; fouling of heat transfer surfaces at high pressures; and operation and cleaning of heat transfer equipment in dirty gas environments.

Bryers, R.W. (ed.)

1983-01-01

187

Liquid droplet heat exchanger studies  

International Nuclear Information System (INIS)

Recent analytical and experimental investigations of the liquid droplet heat exchanger (LDHX) concept for space power applications are described. The performance of the LDHX is compared to that of a conventional heat exchanger for heat rejection applications in a Brayton cycle, using the mass-specific heat exchanger effectiveness as a figure of merit. It is shown that the LDHX has an order of magnitude advantage over the conventional heat exchanger. Furthermore, significant improvement in cycle efficiency and power to mass ratio is possible. Two-phase flow experiments in a laboratory scale LDHX, using air and water as the two media, show very good agreement with the quasi-one-dimensional model used in the parametric studies. 9 references.

1987-01-01

188

Heat exchanger with ceramic elements  

Energy Technology Data Exchange (ETDEWEB)

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.

Corey, John A. (North Troy, NY)

1986-01-01

189

Heat exchanger using graphite foam  

Science.gov (United States)

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.

Campagna, Michael Joseph; Callas, James John

2012-09-25

190

Heat exchange system with reversing receiver flow  

Energy Technology Data Exchange (ETDEWEB)

A heat exchange system is described comprising a compressor; first and second heat exchangers; an expansive valve; a receiver; flow direction reversing means; and conduit means interconnecting the compressor, the heat exchangers, the expansion valve, the receiver and the reversing valve to form a system containing refrigerant in which heat can be exchanged in either direction between the exchangers.

Jones, R.D.

1987-04-07

191

Tubular heat exchanger for a nuclear reactor  

International Nuclear Information System (INIS)

[en] Heat exchanger appliance, featuring a first heat exchanger to bring the heating fluid and a heated fluid into thermal communication by flow of the fluids inside this exchanger, and a pre-cooling heat exchanger arranged in one unit inside the first heat exchanger for the purpose of bringing the heating fluid into thermal communication with the heating fluid flowing in the first heat exchanger, so that the temperature of the heating fluid is lowered before it is placed in thermal communication with the heated fluid

1978-06-22

192

Damping of heat exchanger tubes  

International Nuclear Information System (INIS)

Damping information is required for flow-induced vibration analyses of heat exchangers. There are several possible energy dissipation mechanisms that contribute to overall tube damping, including structural damping, friction damping, tube-to-fluid viscous damping and squeeze-film damping. These mechanisms and their relative contribution to overall tube damping are discussed. The approach is to identify the more important energy dissipation mechanisms and to formulate them in terms of heat exchanger tube parameters. This will give the designer a method to evaluate overall tube damping. The results of recent measurements on a simple two-span heat exchanger tube, on tube bundles in two-phase cross-flow, and on real heat exchangers in the field are disscussed

1985-01-01

193

Assessment of flow induced vibration in a sodium-sodium heat exchanger  

International Nuclear Information System (INIS)

The 500 MWe Prototype Fast Breeder Reactor (PFBR) is under construction at Kalpakkam. It is a liquid metal sodium cooled pool type fast reactor with all primary components located inside a sodium pool. The heat produced due to fission in the core is transported by primary sodium to the secondary sodium in a sodium to sodium Intermediate Heat Exchanger (IHX), which in turn is transferred to water in the steam generator. PFBR IHX is a shell and tube type heat exchanger with primary sodium on shell side and secondary sodium in the tube side. Since IHX is one of the critical components placed inside the radioactive primary sodium, trouble-free operation of the IHX is very much essential for power plant availability. To validate the design and the adequacy of the support system provided for the IHX, flow induced vibration (FIV) experiments were carried out in a water test loop on a 60 deg. sector model. This paper discusses the flow induced vibration measurements carried out in 60 deg. sector model of IHX, the modeling criteria, the results and conclusion.

2009-01-01

194

Assessment of flow induced vibration in a sodium-sodium heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

The 500 MWe Prototype Fast Breeder Reactor (PFBR) is under construction at Kalpakkam. It is a liquid metal sodium cooled pool type fast reactor with all primary components located inside a sodium pool. The heat produced due to fission in the core is transported by primary sodium to the secondary sodium in a sodium to sodium Intermediate Heat Exchanger (IHX), which in turn is transferred to water in the steam generator. PFBR IHX is a shell and tube type heat exchanger with primary sodium on shell side and secondary sodium in the tube side. Since IHX is one of the critical components placed inside the radioactive primary sodium, trouble-free operation of the IHX is very much essential for power plant availability. To validate the design and the adequacy of the support system provided for the IHX, flow induced vibration (FIV) experiments were carried out in a water test loop on a 60 deg. sector model. This paper discusses the flow induced vibration measurements carried out in 60 deg. sector model of IHX, the modeling criteria, the results and conclusion.

Prakash, V. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India)], E-mail: prakash@igcar.gov.in; Thirumalai, M.; Prabhakar, R.; Vaidyanathan, G. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India)

2009-01-15

195

Heat exchanger fouling and corrosion  

International Nuclear Information System (INIS)

Fouling of heat transfer surfaces introduces perhaps the major uncertainty into the design and operation of heat exchange equipment. After a brief description of the various types of fouling the chapter goes on to review the current theories of fouling including the turbulent burst theory. Fouling in equipment involving boiling and evaporation is often more severe than in single phase heat exchangers and moreover, in aqueous systems, is frequently associated with corrosion. The reasons for this are identified and illustrated by reference to corrosion in nuclear power plant steam generators. Finally the modification of heat transfer and pressure drop characteristics by fouling layers is briefly reviewed.

1986-01-01

196

Solar radiant energy heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A radiant energy heat exchanger for use in a solar energy power plant comprises one or more banks of heat exchange ducts, each bank of ducts having an inlet and an outlet manifold to receive and discharge the medium to be heated. The ducts are curved along their length between the inlet and outlet manifolds so that the amount of radiant energy falling on the ducts per unit area of duct decreases between the inlet and outlet manifolds at such a rate that the duct temperature is substantially constant between the manifolds while the temperature of the medium being heated increases, the radiant energy falling on the ducts being substantially unidirectional.

Jubb, A.; Stansbury, E.W.

1980-09-16

197

Stress analysis of heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

This paper presents procedures for computing stresses in floating-head and fixed tubesheet heat exchangers. It does not cover U-tube exchangers. It was prepared in connection with the activities of the Special Working Group on Heat Transfer Equipment, Section VIII, of the ASME Boiler and Pressure Vessel Code Committee, for their use and consideration in the drafting of code rules for these items.

Soehrens, J.E.

1987-01-01

198

Designing heat exchangers by computer  

Energy Technology Data Exchange (ETDEWEB)

The design of heat exchangers by computer has come a long way in a short time due to the explosive development of computer hardware and the ingenuity of the software developers. It is already possible to design by computer a reasonably-sized heat exchanger for most services. However, the future potential is great for the computer to simulate performance for troubleshooting, optimum selection, and even operator training.

Palen, J.W.

1986-07-01

199

Heat exchangers with tube bundles  

Energy Technology Data Exchange (ETDEWEB)

A heat exchangr is described for heat-transfer between substances of high pressure difference including a shell, a region through which a cooler substance is conveyed; an inlet for the cooler substance; a bundle of tubes arranged in a cooler substance compartment; and riser conduits operatively connectible to the shell and communicating with the compartment, with the substance to be cooled being passed through the tubes having a high temperature at the inlet of the heat exchanger and at the outlet; a tube bottom of predetermined thickness arranged at the heat exchanger inlet; and a device including a support-grating arranged in the vicinity of the tube bottom, operatively connectible to the shell and extending at least nearly perpendicular to the tube bottom in the region through which the cooler substance is conveyed. The heat exchanger also includes a top provided with apertures and the like which are easily accessible from the steam-water space of the heat exchanger with cooling channels being provided which are adapted to be in communication with the apertures and riser conduits provided outside the heat exchanger proper.

Deuse, K.; Drobka, W.

1980-12-02

200

OTEC-1 power system test program: performance of one-megawatt heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Heat exchanger test results for the first deployment of OTEC-1 are reported. These tests were aimed at evaluating the performance of a state-of-the-art, 1-MWe titanium shell-and-tube evaporator and condenser in an ocean environment. The evaporator consisted of both a plain and an enhanced (Union Carbide High Flux) tube bundle, whereas the condenser had plain tubes only. All tests with the evaporator were conducted in the sprayed-bundle mode. Experimental results for the condenser and plain-tube portion of the evaporator were in excellent agreement with performance predictions. This result demonstrates that the thermal performance of large plain-tube heat exchangers can be predicted with a high level of confidence. However, the performance of the enhanced-tube portion of the evaporator was much lower thn predicted. Evidence strongly suggested that this poor performance was attributable mainly to fouling of the High Flux surface by corrosion products consisting predominantly of hydrated aluminum oxides.

Lorenz, J.J.; Yung, D.; Howard, P.A.; Panchal, C.B.; Poucher, F.W.

1981-11-01

 
 
 
 
201

Methods for detecting fouling in heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Heat exchangers are frequently used in district heating systems, at power plants and public homes. Detecting fouling in district heating heat exchangers is of great importance. There are currently many different ways to detect fouling in heat exchangers that either rely on physical examination of the heat exchanger or modeling the heat exchanger and use measurements of the heat exchanger to predict fouling. The method describe in the paper can be used to detect fouling by using the inlet and outlet temperatures and either the hot or cold mass flow. Results of the method described on a simulated data are given

Gudmundsson, Oddgeir; Palsson, Olafur Petur; Palsson, Halldor (Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, Univ. of Iceland, Reykjavik (Iceland)); Lalot, Sylvain (LME, Univ. of Valenciennes and Hainaut Cambresis, IUT (France))

2008-09-15

202

Simulation and economic analysis of a liquid-based solar system with a direct-contact liquid-liquid heat exchanger, in comparison to a system with a conventional heat exchanger  

Science.gov (United States)

Using a solar computer simulation package called TRNSYS, simulations of the direct contact liquid-liquid heat exchanger (DCLLHE) solar system and a system with conventional shell-and-tube heat exchanger were developed, based in part on performance measurements of the actual systems. The two systems were simulated over a full year on an hour-by-hour basis at five locations; Boston, Massachusetts, Charleston, South Carolina, Dodge City, Kansas, Madison, Wisconsin, and Phoenix, Arizona. Typically the direct-contact system supplies slightly more heat for domestic hot water and space heating in all locations and about 5 percentage points more cooling as compared to the conventional system. Using a common set of economic parameters and the appropriate federal and state income tax credits, as well as property tax legislation for solar systems in the corresponding states, the results of the study indicate for heating-only systems, the DCLLHE system has a slight life-cycle cost disadvantage compared to the conventional system. For combined solar heating and cooling systems, the DCLLHE has a slight life-cycle cost advantage which varies with location and amounts to one to three percent difference from the conventional system.

Brothers, P.; Karaki, S.

203

Materials Development for HTGR Heat Exchangers.  

Science.gov (United States)

Some versions of the HTGR generate high primary coolant gas temperatures (850 exp 0 to 950 exp 0 C) and exchange this heat, through intermediate heat exchangers (IHX's), to a secondary loop for higher temperature process heat applications. Although IHX's ...

W. R. Johnson D. I. Roberts

1982-01-01

204

Solar heat exchange panel  

Energy Technology Data Exchange (ETDEWEB)

Heat-absorbing bars having a v-shape are placed parallel to one another in a spaced relationship over a reflective surface. Sunlight strikes the bars on their exposed surface and also off the reflective surface against the underside of the bars. Water tubes may also be used.

Thorne, N.J.

1980-09-09

205

Corrosion protected reversing heat exchanger  

International Nuclear Information System (INIS)

A reversing heat exchanger of the plate and fin type having multiple aluminum parting sheets in a stacked arrangement with corrugated fins separating the sheets to form multiple flow paths, means for closing the ends of the sheets, an input manifold arrangement of headers for the warm end of of the exchanger and an output manifold arrangement for the cold end of the exchanger with the input air feed stream header and the waste gas exhaust header having an alloy of zinc and aluminum coated on the inside surface for providing corrosion protection to the stack

1984-01-01

206

Corrosion protected reversing heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A reversing heat exchanger of the plate and fin type having multiple aluminum parting sheets in a stacked arrangement with corrugated fins separating the sheets to form multiple flow paths, means for closing the ends of the sheets, an input manifold arrangement of headers for the warm end of of the exchanger and an output manifold arrangement for the cold end of the exchanger with the input air feed stream header and the waste gas exhaust header having an alloy of zinc and aluminum coated on the inside surface for providing corrosion protection to the stack.

Zawierucha, R.

1984-09-25

207

New heat exchanger conception applied to the heat pumps  

Energy Technology Data Exchange (ETDEWEB)

Improvements to the heat exchangers for heat pumps are presented in this paper. During the latterly years there has been an evolution in the geometries of tubes used as the exchange surface of heat exchange apparatus: different techniques which are commercially available are discussed in this article. The recent appearance of plate heat exchanger as condenser and evaporator have evolved.

Marvillet, C.

1987-09-01

208

Flow distribution analysis in nuclear heat exchangers with application to CRBRP-IHX  

International Nuclear Information System (INIS)

The shell side flow distribution of a shell-and-tube heat exchanger, in which the shell side fluid moves downwards in an axial/cross flow combination dictated by the design of the flow baffles, is examined. Depending on the degree of overlapping and perforation of the baffles, the magnitude of the cross flow component can be controlled in a manner compatible with the unit design. Axial/cross flow field would yield a relatively small pressure drop on the shell side, and in the meantime it creates sufficient fluid mixing to minimize any thermal unbalance among the heat transfer tubes. Such requirements are essential in the design of nuclear heat exchangers similar to the CRBRP-IHX. The present flow distribution analysis utilizes two models: The lumped model and the detailed model. The lumped model employs an overall flow distribution and pressure drop approach to determine the magnitudes of the axial and cross flow components as a function of the baffle overlapping and baffle perforation. The detailed model utilizes more of a fundamental approach in solving the governing equations for the conservation of mass and momentum of a turbulent flowing fluid in a nodal mesh. The mesh incorporates distributed resistances resulting from the presence of the heat transfer tubes and the flow baffles in the tube bundle. The model employs a modified version of the computer code VARR II tailored specifically to the analysis of the shell side flow of heat exchangers. The results of both models are indicated and compared with emphasis on demonstrating the influence of the baffle overlapping and baffle perforation on the flow field and the pressure distribution

1976-06-21

209

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2004-03-26

210

Ceramic heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A tube containment system. The tube containment system does not significantly reduce heat transfer through the tube wall. The contained tube is internally pressurized, and is formed from a ceramic material having high strength, high thermal conductivity, and good thermal shock resistance. The tube containment system includes at least one ceramic fiber braid material disposed about the internally pressurized tube. The material is disposed about the tube in a predetermined axial spacing arrangement. The ceramic fiber braid is present in an amount sufficient to contain the tube if the tube becomes fractured. The tube containment system can also include a plurality of ceramic ring-shaped structures, in contact with the outer surface of the tube, and positioned between the tube and the ceramic fiber braid material, and/or at least one transducer positioned within tube for reducing the internal volume and, therefore, the energy of any shrapnel resulting from a tube fracture.

LaHaye, Paul G. (Kennebunk, ME); Rahman, Faress H. (Portland, ME); Lebeau, Thomas P. E. (Portland, ME); Severin, Barbara K. (Biddeford, ME)

1998-01-01

211

Heat exchangers for HHT plants  

International Nuclear Information System (INIS)

[en] Closed gas turbine installations are equipped with recuperator, precooler and, depending on the design concept, intercooler. If the heat source is a nuclear reactor, core auxiliary heat interchangers must be provided additionally. The report deals with the corresponding heat exchangers of the HHT reference plant (high-temperature reactor with helium turbine). (orig.)[de] Geschlossene Gasturbinenanlagen sind mit Rekuperator, Vorkuehler und je nach Auslegung auch Zwischenkuehler ausgeruestet. Ist die Waermequelle ein Kernreaktor, so sind auch Nachwaermeabfuhr-Kuehler vorzusehen. Der Bericht behandelt die entsprechenden Waermetauscher der HHT-Referenzanlage (Hochtemperaturreaktor mit Heliumturbine). (orig.)

1979-01-01

212

Heat Transport Study of the Laminar Heat Pipe Heat Exchanger  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this experiment is to analyze the performance of the Laminar Heat Pipe Heat Exchanger. The test samples were divided two groups, one is the metal corrugated sheet with heat pipe, and the other is the metal corrugated sheet only. By dipping these two group samples into hot water and to...

Wei-Keng Lin; Ke Chine Liaw; Min-Zen Tsai; Min-Gung Chu

213

Fouling analyses for heat exchangers of NPP  

International Nuclear Information System (INIS)

Fouling of heat exchanges is generated by water-borne deposits, commonly known as foulants including particulate matter from the air, migrated corrosion produces; silt, clays, and sand suspended in water; organic contaminants; and boron based deposits in plants. This fouling is known to interfere with normal flow characteristics and reduce thermal efficiencies of heat exchangers. In order to analyze the fouling for heat exchangers of nuclear power plant, the fouling factor is introduced based on the ASME O and M codes and TEMA standards. This paper focuses on the fouling analyses for the heat exchangers of several primary systems; the RHR heat exchanger of the residual heat removal system, the letdown heat exchanger of the chemical and volume control system, and the CCW heat exchanger of the component cooling water system, Based on the results of the fouling levels for the three heat exchangers are assumed.

2000-01-01

214

Forensic analysis of failed heat exchanger tubes of NGL cooler of gas processing installation  

Energy Technology Data Exchange (ETDEWEB)

Regular failures of heat exchangers in NGL cooler of gas processing installation of Oil and Natural Gas Corporation have been observed during the last few years. These heat exchangers are of shell and tube type. The failures were reported to be on tubes side only and none of the shell failed. Detailed laboratory investigations to examine the objective evidence presented by the failed components to determine the corrosion mechanism leading to failure, were carried out and the results of the said forensic analysis is reported in this paper. The corrosion morphology suggests that it is primarily a concentration cell corrosion type by under deposit attack and pinholes were found below the deposit in the internal surface of the exchanger tube. The corrosion product is magnetic in nature and the dominant peaks in the X-ray diffraction spectra are of Iron oxide in the form of magnetite, Fe{sub 3}O{sub 4}. The exchanger tube material was found to be highly susceptible to severe crevice corrosion under deposits in the electrochemical Tafel plot and cyclic polarisation studies under simulated test conditions using high pressure high temperature autoclave. During the last 3 to 4 years, maximum values recorded for the inorganic phosphate and total hardness in the quality control tests of cooling water were found to be higher than the acceptable limit while the zinc content was found to be falling below the acceptable limit. The decomposition of organic component of phosphate has led to insufficiency in the required dose of phosphate. Higher inorganic component of phosphates along with higher hardness led to precipitation and as such inorganic phosphate was found in the deposits. Therefore protective film formation was insufficient to mitigate under deposit pitting corrosion. Dose of 15 ppm total phosphate (having 40 to 60% organic phosphate form) and a minimum of 2 to 3 ppm zinc concentration were recommended to avoid recurrence of under deposit pitting corrosion. (authors)

Bhat, S.S.; Kapoor, I.R.; Katarki, M.V. [Materials and Corrosion Section, Institute of Engineering and Ocean Technology, Oil and Natural Gas Corporation Limited, Panvel, Navi Mumbai, 410221 (India)

2004-07-01

215

Tube-type heat exchanger  

International Nuclear Information System (INIS)

The tube-type heat exchanger consists of a cylindrical casing in which are mounted U shaped heat exchange tubes anchored in a tube plate. The individual tubes of the inlet and outlet branch are fitted in support partitions normal to the axis of the tubes and provided with fins. The length of the fin equals half of the length of the chord of the support partition. The fins of the partitions of the inlet branch fit close to the partitions of the outlet branch and vice versa. The fin nearest to the tube plate comes into contact with the inner wall of the tube plate. Support partitions, fins and the inner surface of the casing thus form a helical throughflow channel to which are tangentially connected the inlet and outlet necks. (E.S.)

1979-03-08

216

Radiative heat exchange between surfaces  

International Nuclear Information System (INIS)

[en] The geometrical features of radiative heat exchange between surfaces are discussed first by developing various radiation shape factor relations. The governing equations for enclosures with diffusely emitting and diffusely reflecting surfaces, as well as the equations for enclosures with gray surfaces having specular component of reflectivity are introduced next. Finally, a simplified model for enclosures with isothermal surfaces under the assumption of uniform radiosity over the surfaces is discussed, and various working relations for different conditions are presented

1986-07-04

217

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

International Nuclear Information System (INIS)

[en] 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.)

1979-01-01

218

Part 1: Experimental hydrodynamic study of the slurry distribution in a vertical slurry heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

The flow in a slurry heat exchanger is simulated experimentally to investigate the concentration distributions resulting from a parametric variation of total flow rates, slurry concentration and particle size anticipated in a typical application of the heat exchanger in a Solvent Refined Coal process (SRC-1). The experimental facility consisted of a heat exchanger with 27 tubes set on a grid exactly equal to the one suggested by a typical SRC-I plant arrangement. Knowing these factors is important because these distributions can affect also the local heat transfer mechanisms in those heat exchangers and can affect the overall thermal efficiency. The shell and tube heat exchanger is oriented vertically with upward slurry flow on the tube side to minimize the localized solid sedimentation in individual tubes. Two sizes of glass beads such as 125 and 250 {micro}m were used to simulate the coal particles. The two batches used had a very small standard deviation error for their distribution and can essentially be considered as uniform in size. The use of glass beads was needed because the flow system was a recirculating one and the need to prevent particle size attrition was important. A special pneumatically activated slurry recirculating pump with a rubber diaphragm piston was used to minimize this attrition. Three average slurry concentrations were used for the study, which varied from 113.0--341.0 kg/m{sup 3}. The average flow velocity in each of the tubes was varied between 0.448--0.61 m/s. These conditions bracket to a reasonable degree the normal operations of an SRC-I plant. It was found that the individual tube flow rates are highest for the central tubes and lower for the peripheral ones. However, with the addition of solids, the flow distribution becomes more even. Moreover, it was observed that with the smaller particle size solids and higher overall flow rates, the slurry concentration and flow distribution across the heat exchanger tubes becomes more even. These results indicate that a more careful and detailed study of the effects of slurry flow distributions need to be undertaken in regards to thermal performance than what is available in the literature.

Moujaes, S.F.; Shih, C.T.

1999-07-01

219

Optimization of heat exchanger for indirectly heated water heater  

Science.gov (United States)

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.

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

2012-04-01

220

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.

2011-01-01

 
 
 
 
221

Fouling analyses of heat exchangers for PSR  

International Nuclear Information System (INIS)

Fouling of heat exchangers is generated by water-borne deposits, commonly known as foulants including particulate matter from the air, migrated corrosion produces; silt, clays, and sand suspended in water; organic contaminants; and boron based deposits in plants. This fouling is known to interfere with normal flow characteristics and reduce thermal efficiencies of heat exchangers. This paper focuses on fouling analyses for six heat exchangers of two primary systems in two nuclear power plants; the regenerative heat exchangers of the chemical and volume control system and the component cooling water heat exchangers of the component cooling water system. To analyze the fouling for heat exchangers, fouling factor was introduced based on the ASME O and M codes and TEMA standards. Based on the results of the fouling analyses, the present thermal performances and fouling levels for the six heat exchangers were predicted.

2003-01-01

222

Tubular heat exchangers. Rohrbuendel-Waermeaustauscher  

Energy Technology Data Exchange (ETDEWEB)

Depending on the field of application or on the use of the medium, heat exchangers which work according to the principle of counterflow, parallel flow or cross-flow are used in the area of heating technology, in service water heating or cooling systems. Heat exchangers with hair pin tube bundles, as two plate device, or with electric insert, water vapor generators and tube-in-tube heat exchangers are differentiated. Structure and mode of operation of tubular heat exchangers are explained with reference to the regulations. Compared to plate heat exchanges it shows that plate heat exchangers are more compact and that due to the embossed plates high velocities and turbulances can be produced in the narrow water pipes but this has the disadvantage that they are sensitive to pressure shock and soiling. (BWI).

Laeng, H. (Markom AG, Zurich (Switzerland))

1991-03-01

223

Membrane and plastic heat exchangers performance  

Directory of Open Access Journals (Sweden)

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.

Mohammad Shakir Nasif; Graham L. Morrison; Masud Behnia

2005-01-01

224

Heat exchanger with antivibration structure  

International Nuclear Information System (INIS)

Flow induced vibration of heat exchanger U-tubes is minimised by the use of generally V-shaped antivibration bars inserted into the tube bundle at the U-shaped sections thereof, the bars inserted into alternate gaps between adjacent layers of tubes being staggered with respect to those inserted into the adjacent gaps. All of the antivibration bars are interference fits between the tube layers so as to elastically deflect the tubes thereby ensuring positive tube support at each intersection between the tubes and bars. (author).

1985-05-17

225

Heat exchanger for liquid metals  

International Nuclear Information System (INIS)

The heat exchanger is for liquid metals, such as sodium, whereby the secondary liquid metal is fed through parallel pipes in one or more pipe bundles, and wherein the pipes, between pipe plates or other assembly pieces, are introduced, and the primary liquid metal flows or circulates along the outside of the pipes, characterised by that the pipes of the pipe handles consist of molybdenum, tantalum or niobium, or alloys thereof, and the outside diameter lies between 6 and 16 mm at least. (G.C.)

1977-01-01

226

NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger  

Energy Technology Data Exchange (ETDEWEB)

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.

Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

2008-09-01

227

Heat Transport Study of the Laminar Heat Pipe Heat Exchanger  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this experiment is to analyze the performance of the Laminar Heat Pipe Heat Exchanger. The test samples were divided two groups, one is the metal corrugated sheet with heat pipe, and the other is the metal corrugated sheet only. By dipping these two group samples into hot water and to see the thermal image by Infrared thermal imager. The results shown the temperature risen of the sheet with heat pipe was faster than that of the sheet without heat pipe. In addition, the bigger of the temperature difference between hot water temperature and ambient temperature, the quicker of the temperature risen for the metal corrugated sheet, and the temperature of the metal corrugated sheet were homogenous as well. For example, when the water temperature is 30?, ambient temperature is 20?, the metal corrugated sheet with heat pipe rise rapidly to 26? within 1 minute, while the metal corrugated sheet without heat pipe rise to 22? only, this temperature difference would be more obvious with the increasing of the hot water temperature. When the hot water temperature is up to 40?, the metal corrugated sheet with heat pipe rise rapidly to 31? within 1 minute, while the metal corrugated sheet without het pipe is still rise up to 22? only. When the hot water temperature is up to 50?, The metal corrugated sheet with heat pipe rise rapidly to 33? within 1 minute, while the sheet without heat pipe still keep at 22?, the results shown the heat pipe affect the temperature rising speed is obvious, and it also implying heat pipe is a very important parameter for the heat transfer rate of the Laminar Heat Pipe Heat Exchanger.

Wei-Keng Lin; Ke Chine Liaw; Min-Zen Tsai; Min-Gung Chu

2012-01-01

228

Testing and analysis of immersed heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1986-08-01

229

Heat exchanger fouling and corrosion evaluation  

Science.gov (United States)

The experimental determination of acid corrosion and fouling effects upon a series of tubular heat exchanger modules exposed to the exhaust gases from a large (8900-hp) diesel engine, with different fin geometries and materials was studied. A study of the exhaust gas analysis was undertaken and acid dew point temperatures were determined. Heat exchanger test modules were then operated with metal surface temperatures below the acid dew point to allow for acid condensation and fouling. A continuous soot buildup was observed on the heat exchanger, as a function of the diesel engine operating time, heat transfer metal surface temperature, and fin geometry. The corrosion effects on the heat exchangers were minimal.

Deanda, E.

1981-10-01

230

Spiral-passage heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A spiral passage chemical converter-heat exchanger formed by a cross-sectional rectangular housing containing a pair of rows each containing a plurality of side-by-side passages is described. The rectangular housing is wound into a spiral with the innermost row forming inlet passages and the outermost row forming outlet passages. Thermal contact exists between inflow passages and outflow passages. The outer end of the spiral is connected with an inlet and an outlet. The inlet joins the innermost row of passages and the outlet joins the outermost row of passages. The inner end of the spiral is capped, with a common wall separating the upper and lower passages slotted so that fluid flows from the inlet passages to the outlet passages. As can be seen when the structure is in a spiral, the inlet passages are between the outlet passages with the outlet passages forming the outer exposed surface of the spiral and the inlet passages forming the surface of the opening through the spiral at the center. A concave sunlight reflector will focus sunlight into the central opening of the spiral thereby heating the fluid in the inlet passages. Since the outlet passages are separated by the inlet passages in the spiral and are in thermal contact therewith, the solar heated outlet fluid will heat the input fluid as it circles the spiral to the outlet passages.

Chubb, T.A.

1980-06-10

231

Spiral-passage heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A spiral passage chemical converter-heat exchanger is formed by a cross-sectionally rectangular housing containing a pair of rows each containing a plurality of side-by-side passages. The rectangular housing is wound into a spiral with the innermost row forming inlet passages and the outermost row forming outlet passages. Thermal contact exists between inflow passages and outflow passages. The outer end of the spiral is connected with an inlet and an outlet. The inlet joins the innermost row of passages and the outlet joins the outermost row of passages. The inner end of the spiral is capped, with a common wall separating the upper and lower passages slotted so that fluid flows from the inlet passages to the outlet passages. As can be seen when the structure is in a spiral, the inlet passages are between the outlet passages with the outlet passages forming the outer exposed surface of the spiral and the inlet passages forming the surface of the opening through the spiral at the center. A concave sunlight reflector will focus sunlight into the central opening of the spiral thereby heating the fluid in the inlet passages. Since the outlet passages are separated by the inlet passages in the spiral and are in thermal contact therewith, the solar heated outlet fluid will heat the input fluid as it circles the spiral to the outlet passages. Thus, the outlet passages aid in heating the inlet fluid during passage to the inner end of the spiral. The inlet passages may contain a porous catalyst which is prevented from escaping by a suitable structure at each end of the inlet passages for dissociating a fluid for storage of heat for future use.

Chubb, T.A.

1980-06-10

232

Air-sand heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

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.

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

233

Food Processing Vat With Heat Exchangers  

UK PubMed Central (United Kingdom)

A food processing vat is provided with a zoned heat transfer system that includes a heat exchanger with a baffle that extends between a pair of spaced apart sheets. The baffle directs a flow of a heat transfer fluid through a void space between the sheets of the heat exchanger. The heat exchanger may also include multiple spaced apart posts that extend through the heat exchanger and around which the heat transfer fluid can flow. The posts and/or baffle may be defined by welded points of joinder between the sheets, and the sheets may be inflated to provide the space therebetween, such that the posts and/or baffles extend as webs of material that connect the sheets of the heat exchanger.

ISENBERG TIMOTHY J; ZIRBEL JOHN E

234

Food processing vat with heat exchangers  

UK PubMed Central (United Kingdom)

A food processing vat is provided with a zoned heat transfer system that includes a heat exchanger with a baffle that extends between a pair of spaced apart sheets. The baffle directs a flow of a heat transfer fluid through a void space between the sheets of the heat exchanger. The heat exchanger may also include multiple spaced apart posts that extend through the heat exchanger and around which the heat transfer fluid can flow. The posts and/or baffle may be defined by welded points of joinder between the sheets, and the sheets may be inflated to provide the space therebetween, such that the posts and/or baffles extend as webs of material that connect the sheets of the heat exchanger.

ISENBERG TIMOTHY J; ZIRBEL JOHN E

235

Heat exchanger for automobiles. Waermetauscher fuer Kraftfahrzeuge  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger for automobiles with inlet and outlet openings for the heat transfer medium and cooling air passages has improved in a way that the cooling medium flows from the inlet to the outlet in a way that the covered zone is at the same time the coolest part of the heat exchange surface.

Schmehl, T.; Breuer, N.

1992-10-22

236

Gas log fireplace heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

A gas fueled heat exchange machine consists of a fan-driven, air fed, sealed chamber manifold resting flush on the base of a fireplace and centered square to its back wall. A series of cylindrical thick-walled ceramic tubes act as heated air conduits which are inset with heat-resistant cement both in the rear manifold and in the extended forward ends of the front body wall at the fireplace opening. Desirably the sealed air chamber is rectangular and has horizontal fixed louvered fins across its lower front to allow room-temperature air to be drawn upward from the cooler floor level into the fireplace, then forced through the lint-filtered sealed chamber and manifold and heated ceramic conduits, returning the warmed air to the room by vertical-slatted louvers which divert the air flow to ascend at wide angles from the machine. The forced air cycle is provided by an electric transflow blower which is heat protected inside the sealed chamber at the internal base of the manifold. On the top surface of the seald chamber, there is a horizontal U-shaped gas burner with a controllable primary air inlet on the underside thereof, together with side vents on both ends of the machine's walls to provide secondary combustion air supply. The hollow gas burner has a plurality of apertures on its top, spaced apart and in varying sizes, forming a consistent design which governs the height of the gas flame in a regulated undulating pattern.

1988-07-19

237

Analytical Entropy Analysis of Recuperative Heat Exchangers  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Antun Galovic; Zdravko Virag; Marija Zivic

2003-01-01

238

OPTIMASI KINERJA HEAT EXCHANGER TABUNG KOSENTRIS  

Directory of Open Access Journals (Sweden)

Full Text Available Heat exchanger effectiveness is affected by some factors such as pipe shape, temperature, cold and hot air direction and velocity entering the heat exchanger. Research about heat exchanger has been done but the significance level of the heat exchanger effectiveness resulted is unknown. A designed experiment should be done to optimize the performance of concentric tube heat exchanger with measured significance level. From the analysis of result of previous experiment, factors that seem to affect the effectiveness are velocity of cold air, velocity of hot air, and pipe shape of heat exchanger used (outlet and inlet similar to U, S and L shape). Experimental design that is used here is three-level factorial design. On the arrangement of factors as follows: velocity of cold air = 4 m/s, velocity of hot air = 7 m/s, and pipe of S shape, optimum effectiveness gained at significance level of 95 % is 0,39098. Abstract in Bahasa Indonesia : Efektifitas heat exchanger tabung konsentris bisa dipengaruhi oleh beberapa faktor, antara lain bentuk pipa, temperatur, arah aliran dan kecepatan udara masuk baik dingin maupun panas. Penelitian mengenai heat exchanger telah dilakukan sebelumnya namun tingkat signifikasi dari efektifitas heat exchanger yang dihasilkan tidak diketahui. Suatu eksperimen yang terancang perlu dilakukan untuk mengoptimalkan kinerja dari heat exchanger tabung kosentris dengan tingkat signifikasi yang terukur. Dari analisa terhadap hasil eksperimen terdahulu, tampak bahwa faktor yang berpengaruh adalah kecepatan udara dingin, kecepatan udara panas dan bentuk pipa heat exchanger (outlet dan inlet menyerupai bentuk U, S dan L) yang digunakan. Rancangan eksperimen yang digunakan ialah rancangan faktorial 3 level. Pada pengaturan level faktor sebagai berikut: kecepatan udara dingin = 4 m/det, kecepatan udara panas = 7 m/det dan bentuk tabung yang digunakan ialah pipa berbentuk S, diperoleh efektifitas optimum pada tingkat signifikasi 95 % = 0,39098. Kata kunci: heat exchanger, desain eksperimen, efektifitas

Didik Wahjudi

2000-01-01

239

Basic design methods of heat exchangers  

International Nuclear Information System (INIS)

The most common heat exchanger design problems are rating and sizing problems. In this paper the basic design methods for two-fluid direct-transfer heat exchangers are reviewed. A heat exchanger is a device in which heat is transferred from a hot fluid to a cold fluid. In its simplest form, the two fluids mix and leave at an intermediate temperature determined by the conservation of energy. This device is not truly a heat exchanger but rather a mixer. In most applications, the fluids do not mix but transfer heat through a separating wall that takes on a wide variety of geometries. Three categories are normally used to classify heat exchangers: recuperators, regenerators, and direct-contact apparatus

1991-01-01

240

Heat exchanger development in the 1980s  

Energy Technology Data Exchange (ETDEWEB)

Heat exchanger development plays an important role in nuclear engineering. The author discusses improvements in materials for better thermal efficiency and considers safety aspects and future prospects.

Amacker, S. (Sulzer Bros. Ltd., Winterthur (Switzerland))

1982-01-01

 
 
 
 
241

Radiant energy heat exchanger system  

Energy Technology Data Exchange (ETDEWEB)

A radiant energy heat exchanger is described. It comprises a panel structure including a base having a multiplicity of transversely spaced barrier walls extending longitudinally between the end portions of the panel structure. An inner sheet form wall section is sealingly connected with each pair of adjacent barrier walls providing a plurality of inner fluid containing channel spaces extending longitudinally between the end portions of the panel structure, a concavo-convex outer sheet form wall section sealingly connected with each pair of adjacent barrier walls, and an intermediate sheet form wall section between the associated inner and outer wall sections defining a multiplicity of outer and intermediate fluid containing spaces in outwardly disposed relation with respect to the multiplicity of inner fluid containing channel spaces.

Mcalister, R.E.

1981-07-21

242

Heat flow characteristics of underground closed geothermal heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

In the paper there are presented the heat flow characteristics of an underground closed geothermal heat exchanger (UCGHE). The calculations were performed with the model described in the paper. These characteristics determine how the possible to extract heat flow changes in a function of temperature difference on the input and output of the exchanger. (orig.)

Kujawa, T.; Kaczmarek, R. [Szczecin Univ. of Tech. (Poland). Dept. of Heat Engineering

2006-07-01

243

Heat exchanging with slowly rotating finned elements  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanging apparatus is described comprising, substantially parallel heat transfer elements each having a longitudinal axis in a plane perpendicular to the normal direction of fluid therethrough; a source of a fluid having lint particles and moving in a flow direction; means for supporting the heat transfer elements for intercepting the moving fluid for heat exchange in the flow direction having a major component substantially perpendicular to the plane; the fluid having lint particles which if allowed to accumulate would clog the heat exchanging apparatus and obstruct the flow of the fluid; each heat transfer element having fin means extending radially outward from an element longitudinal axis for increasing the heat transfer between the fluid and each heat transfer element; means for rotatably supporting each of the heat transfer elements; means for producing fluid flow; and means for slowly continuously rotating the heat transfer elements.

Deck, B.D.

1987-04-28

244

Plate heat exchangers design, applications and performance  

CERN Multimedia

Heat exchangers are important, and used frequently in the processing, heat and power, air-conditioning and refrigeration, heat recovery, transportation and manufacturing industries. Such equipment is also important in electronics cooling and for environmental issues like thermal pollution, waste disposal and sustainable development.The present book concerns plate heat exchangers (PHEs), which are one of the most common types in practice. The overall objectives are to present comprehensive descriptions of such heat exchangers and their advantages and limitations, to provide in-depth thermal and

Wang, L; Manglik, R M

2007-01-01

245

Optimization of heat exchanger for indirectly heated water heater  

Directory of Open Access Journals (Sweden)

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.

Kaduchová Katarína; Lenhard Richard; Janda?ka Jozef

2012-01-01

246

Conjugate heat and mass transfer in heat mass exchanger ducts  

CERN Multimedia

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

Zhang, Li-Zhi

2013-01-01

247

Experimental investigation of a manifold heat-pipe heat exchanger  

International Nuclear Information System (INIS)

Results of experimental investigations of a heat exchanger on a manifold water heat pipe are given. An analysis is made of the temperature distribution along the heat-transfer agent path as a function of the transferred heat power. The influence of the degree of filling with the heat transfer agent on the operating characteristics of the construction is considered

1995-01-01

248

Optimum geometry of MEMS heat exchanger for heat transfer enhancement  

Directory of Open Access Journals (Sweden)

Full Text Available The study is based on an analysis of MEMS heat exchanger of three different geometries: wavy, triangular and rectangular using water as test fluid. The problem is solved using finite element method. The aim of this analysis is to evaluate the performance of MEMS heat exchanger for different geometry and to obtain an optimum design for better heat enhancement. It is apparent from this work that rectangular surface heat exchanger shows the best performance for heat enhancement technique in comparison to other geometry. Moreover, it is also easy to manufacture. Therefore, the rectangular surface may be used instead of other configurations of heat transfer surfaces. In this analysis, emphasis is given on enhancing heat transfer area of MEMS heat exchanger by reducing the pitch which shows that 0.475 mm is the optimum pitch as further decrease of pitch length does not have any significant effect on the effectiveness and heat transfer.

Nusrat J. Chhanda; Muhannad Mustafa; Maglub Al Nur

2010-01-01

249

Solar water heating system and heat exchanger therefor  

Energy Technology Data Exchange (ETDEWEB)

In a solar water system including a solar collector prevention of damage to the collector during freezing conditions is achieved by providing a relatively small independent heat exchanger between the solar collector and the water heater and a vacuum breaking system whereby the water in the solar collector is drained into the heat exchanger. The heat exchanger is connected to a thermal siphon arrangement with the water heater.

Koskela, M.O.

1982-04-27

250

Experimental evaluation of vibrations in heat exchangers  

International Nuclear Information System (INIS)

[en] 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)

1997-01-01

251

Analytical Entropy Analysis of Recuperative Heat Exchangers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 p...

Antun Galovic; Zdravko Virag; Marija Zivic

252

Condensing heat exchangers for maximum boiler efficiency  

Energy Technology Data Exchange (ETDEWEB)

Until now, boiler efficiency has been limited due to the minimum temperature allowed at the stack. Heat lost up the stack was in exchange for keeping the flue gas temperature above the water vapor dew point. If water vapor was allowed to condense out, rapid deterioration, due to acid corrosion, of the outlet duct and stack would result. With the development of the condensing heat exchanger, boiler efficiency can now exceed 90%. Approximately 1% gain in boiler efficiency can be expected for every 40 F (4.5 C) reduction in flue gas stack temperature. In the CHX{reg_sign} condensing heat exchanger, all gas wetted surfaces are covered with DuPont Teflon{reg_sign}. The Teflon covered heat exchanger surfaces are impervious to all acids normally resulting from the combustion of fossil fuels. This allows the flue gas to be cooled to below the water vapor dew point with no subsequent corrosion of the heat exchanger surfaces.

Johnson, D.W.; DiVitto, J.G.; Rakocy, M.E. [Babcock and Wilcox Co., Barberton, OH (United States). Environmental Equipment Div.

1994-12-31

253

Developing seamless method to calculate heat convection and conduction on cartesian grid  

Energy Technology Data Exchange (ETDEWEB)

In these days, studying and developing algorithms which calculate fluid flows which have interfaces or bodies on cartesian grid become trend of computational fluid dynamics area. In this paper, we propose Virtual Flux Method (VFM) which calculates heat and fluid flow around interfaces or bodies on cartesian grid. This method enables to seamlessly calculate heat convection on the surface of the bodies and fluid and heat conduction inside bodies. In three dimensional calculations of shell and tube type heat exchangers, there is a possibility that fluid inside and outside tubes and heat flow between these fluid and tube bodies are calculated without any kind of extra algorithms but VFM. (author)

Tanno, I. [Graduate School of Kyoto Inst. of Technology, Kyoto (Japan)]. E-mail: itaru@fe.mech.kit.ac.jp; Morinishi, K.; Matsuno, K.; Nishida, H. [Kyoto Inst. of Technology, Kyoto (Japan)

2005-07-01

254

Developing seamless method to calculate heat convection and conduction on cartesian grid  

International Nuclear Information System (INIS)

In these days, studying and developing algorithms which calculate fluid flows which have interfaces or bodies on cartesian grid become trend of computational fluid dynamics area. In this paper, we propose Virtual Flux Method (VFM) which calculates heat and fluid flow around interfaces or bodies on cartesian grid. This method enables to seamlessly calculate heat convection on the surface of the bodies and fluid and heat conduction inside bodies. In three dimensional calculations of shell and tube type heat exchangers, there is a possibility that fluid inside and outside tubes and heat flow between these fluid and tube bodies are calculated without any kind of extra algorithms but VFM. (author)

2005-08-03

255

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

Directory of Open Access Journals (Sweden)

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.

S.P.WALDE; V.M.KRIPLANI

2012-01-01

256

Stirling engine with parallel flow heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger system for a stirling engine includes a heater connected to the expansion space by a pair of parallel flow ducts , and a cooler connected to the compression space by a pair of parallel flow ducts. A circulator is arranged in one of the heater ducts and one of the cooler ducts to continuously circulate working fluid from the working space, through the heat exchanger, and back into the same working space. The expansion and compression processes are thereby made more isothermal and the heat exchangers may be made smaller, more effective and with a lower pressure drop.

Vitale, N.G.

1983-01-11

257

Heat Exchanger Support Bracket Design Calculations  

Energy Technology Data Exchange (ETDEWEB)

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.

Rucinski, Russ; /Fermilab

1995-01-12

258

Heat exchanger with transpired, highly porous fins  

Energy Technology Data Exchange (ETDEWEB)

The heat exchanger includes a fin and tube assembly with increased heat transfer surface area positioned within a hollow chamber of a housing to provide effective heat transfer between a gas flowing within the hollow chamber and a fluid flowing in the fin and tube assembly. A fan is included to force a gas, such as air, to flow through the hollow chamber and through the fin and tube assembly. The fin and tube assembly comprises fluid conduits to direct the fluid through the heat exchanger, to prevent mixing with the gas, and to provide a heat transfer surface or pathway between the fluid and the gas. A heat transfer element is provided in the fin and tube assembly to provide extended heat transfer surfaces for the fluid conduits. The heat transfer element is corrugated to form fins between alternating ridges and grooves that define flow channels for directing the gas flow. The fins are fabricated from a thin, heat conductive material containing numerous orifices or pores for transpiring the gas out of the flow channel. The grooves are closed or only partially open so that all or substantially all of the gas is transpired through the fins so that heat is exchanged on the front and back surfaces of the fins and also within the interior of the orifices, thereby significantly increasing the available the heat transfer surface of the heat exchanger. The transpired fins also increase heat transfer effectiveness of the heat exchanger by increasing the heat transfer coefficient by disrupting boundary layer development on the fins and by establishing other beneficial gas flow patterns, all at desirable pressure drops.

Kutscher, Charles F. (Golden, CO); Gawlik, Keith (Boulder, CO)

2002-01-01

259

Heat exchanger module for secondary circuit of nuclear heating plant  

International Nuclear Information System (INIS)

[en] 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.)

1979-12-27

260

RADIAL DESIGN OXYGENATOR WITH HEAT EXCHANGER  

UK PubMed Central (United Kingdom)

Disclosed is an apparatus for oxygenating and controlling the temperature of blood in an extracorporeal circuit. The apparatus has an inlet and an outlet that is located radially outward from the inlet in order to define a flowpath through the apparatus. The apparatus comprises: a core that is substantially centrally located in the apparatus and to which blood from a patient can be supplied through the inlet a heat exchanger comprising a plurality of heat transfer elements that are arranged around the core and between which blood from the core can move radially outward and an oxygenator comprising a plurality of gas exchange elements that are arranged around the heat exchanger and between which blood from the heat exchanger can move radially outward before exiting the apparatus through the outlet.

CARPENTER WALT L; OLSEN ROBERT W; HOBDAY MICHAEL J; MCLEVISH ALFORD L; PLOTT CHRISTOPHER J; BRISCOE RODERICK E; CLOUTIER PATRICK J; THAPA ANIL; LI MING; MCINTOSH KEVIN; MERTE KEN

 
 
 
 
261

Heat exchanger development in the 1980s  

International Nuclear Information System (INIS)

[en] Heat exchanger development plays an important role in nuclear engineering. The author discusses improvements in materials for better thermal efficiency and considers safety aspects and future prospects. (G.T.H.)

1982-01-01

262

Silicon Carbide Ceramics for Compact Heat Exchangers.  

Science.gov (United States)

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 demonstratin...

D. Zhang D. C. Nagle

2009-01-01

263

Design concept for vessels and heat exchangers  

International Nuclear Information System (INIS)

A design concept for vessels and heat exchangers against internal and external loads resulting from normal operation and accident is shown. A definition and explanation of the operating conditions and stress levels are given. A description of the type of analysis (stress, fatigue, deformation, stability, earthquake and vibration) is presented in detail, also including technical guidelines which are used for the vessels and heat exchangers and their individual structure parts. (Author)

1981-12-18

264

Procedure for repairing a heat exchanger  

International Nuclear Information System (INIS)

This patent describes a procedure for repairing a leaking heat exchanger, made of a casing that encloses a protracted cavity in which a number of separate pipes are arranged for carrying the liquid gas or vapor through the exchanger around which the hot substances are transported for cooling as in a reactor

1975-01-01

265

Small Scale Thermosyphon Heat Exchanger.  

Science.gov (United States)

A small circular heat transfer cell was used to study the cooling of a disc heat source by a thin evaporating liquid film. This small scale thermosyphon is a thermal spreader and a passive heat sink in that the interfacially induced liquid flow rates are ...

M. Sujanani E. W. Kiewra P. C. Wayner

1986-01-01

266

Characteristics of heat flow in recuperative heat exchangers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 logarit...

Lalovi? Milisav; Radovi? Žarko; Jaukovi? Nada

267

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

1980-01-01

268

Evaluation of heat exchange performance for intermediate heat exchanger in HTTR  

International Nuclear Information System (INIS)

In High Temperature Engineering Test Reactor (HTTR) of 30 MW, the generated heat at reactor core is finally dissipated at the air-cooler by way of the heat exchangers of the primary pressurized water cooler and the intermediate heat exchanger (IHX). The heat exchangers in the main cooling system of HTTR must satisfy two conditions, that is, achievement of reactor coolant outlet temperature 850degC/950degC and removal of reactor generated heat 30 MW. Therefore, the heat exchanges have to have the same performance as these in the design. In this report, heat exchange performance of the IHX in the main cooling system was evaluated with the rise-to-power-up test and the in-service operation data. Moreover, the validity of the IHX thermal-hydraulic design method was confirmed by comparison of evaluated data with designed value. (author)

2005-01-01

269

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)

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

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

270

Heat exchanger network optimization strategy based on reducing the number of heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The characteristics of good process design methods are discussed. A skill-based design optimization strategy to reduce the number of heat exchangers in a heat exchanger network (HEN) is proposed, and is compared with the pinch technology approach. It is shown that the Hohmann (or Euler) equation can correctly predict the existence of loops in maximum energy recovery (MER) heat exchanger networks, but cannot accurately predict the minimum number of heat exchangers. It is also found that breaking loops, or creating independent subsets of streams does not always reduce the number of exchangers. The importance of using enthalpy vs. temperature plots of individual process streams as well as those of hot and cold composites is demonstrated. In the absence of other overriding criteria, it is recommended that HEN designs should be selected on the basis of reduced number of heat exchangers.

Sama, D.A. [Univ. of Massachusetts, Lowell, MA (United States). Dept. of Chemical Engineering

1996-12-31

271

Heat exchanger device for a reactor  

International Nuclear Information System (INIS)

High temperature reactor gas is taken in a jacket, in which a bayonet tube device is vertically supported. Water is used as the secondary coolant in it. Heat transfer is produced by forced convection. The gas is circulated by pumps. The heat exchanger is suitable for use in emergency conditions. (DG).

1979-01-01

272

Examples of plate type heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

Gas-gas plate type heat exchanger is produced by the company which the author works for with its design and actual examples. The present heat exchanger can be used, without change in basic structure, in a wide temperature range covering the high temperature (900/sup 0/C at exhaust gas entrance) in the sludge incineration, etc. to the low temperature (150 to 70/sup 0/C exhaust gas) in the dryer exhaust heat recovery of paper machine. An actual example specifies 85 to 70/sup 0/C with 107,400m/sup 3//h on high temperature side, 30 to 52/sup 0/C with 75,300m/sup 3//h on low temperature side, 516,000Kcal/h in heat exchange quantity rate, 669.9m/sup 2/ in heat transfering area, SUS 304 in material and 0.6 mm in thickness. The plate type heat exchanger generally is lighter in weight and smaller in occupying space than the multi-tube type, and can be heightened to heigher than 80% in heat recovery ratio. Different engineered measures have been adopted to it, e.g. by approaching the low temperature side gas temperature to the water dew point of high temperature side gas for the prevention against corrosion or improving the flow conduit and temperature control to keep the heat transfering surface temperature to be higher than the acid dew point. (4 figs)

Fujii, Yasuji

1988-08-30

273

Research of heat exchange rate of the pulsating heat pipe  

Directory of Open Access Journals (Sweden)

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.

Kravets V. Yu.; Naumova A. M.; Vovkogon A. M.

2010-01-01

274

Boiling heat transfer in compact heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Small circular and noncircular channels are representative of flow passages in compact evaporators and condensers. This paper describes results of an experimental study on heat transfer to the flow boiling of refrigerant- 12 in a small circular tube of diameter = 2.46 mm. The objective of the study was to assess the effect of channel size on the heat transfer coefficient and to obtain additional insights relative to the heat transfer mechanisms. The flow channel was made of brass and had an overall length of 0.9 m. The channel wall was electrically heated, and temperatures were measured on the channel wall and in the bulk fluid stream. Voltage taps were located at the same axial locations as the stream thermocouples to allow testing over an exit quality range of 0.21 to 0.94 and a large range of mass flux (63 to 832 kg/m{sup 2}s) and heat flux (2.5 to 59 kW/m{sup 2}). Saturation pressure was nearly constant, averaging 0.82 MPa for most of the testing; a few test data were also taken at a constant lower pressure of 0.52 MPa. Local heat transfer coefficients were determined experimentally. Analysis provided additional support for the conclusion, arrived at from previous studies, that a nucleation mechanism dominates for flow boiling in small channels; nevertheless, a convective-dominant region was identified at very low values of wall superheat (<{approx}3{degrees}C). Previous flow boiling studies in small channels, that did not include wall superheats this low, did not encounter the convective dominant mechanism. Conversely, cryogenic studies at very low wall superheats ({approx}l{degree}C) did not encounter the nucleation dominant regime. The apparent discrepancy is explained by the results of this study.

Tran, T.N.; Wambsganss, M.W. [Argonne National Lab., IL (United States); France, D.M. [Illinois Univ., Chicago, IL (United States). Dept. of Mechanical Engineering

1994-12-31

275

Observer-based monitoring of heat exchangers.  

Science.gov (United States)

The goal of this work is to provide a method for monitoring performance degradation in counter-flow double-pipe heat exchangers. The overall heat transfer coefficient is estimated by an adaptive observer and monitored in order to infer when the heat exchanger needs preventive or corrective maintenance. A simplified mathematical model is used to synthesize the adaptive observer and a more complex model is used for simulation. The reliability of the proposed method was demonstrated via numerical simulations and laboratory experiments with a bench-scale pilot plant. PMID:17706652

Astorga-Zaragoza, Carlos-Manuel; Alvarado-Martínez, Víctor-Manuel; Zavala-Río, Arturo; Méndez-Ocaña, Rafael-Maxim; Guerrero-Ramírez, Gerardo-Vicente

2007-08-15

276

The dry heat exchanger calorimeter system  

Energy Technology Data Exchange (ETDEWEB)

A radiometric isothermal heat flow calorimeter and preconditioner system that uses air instead of water as the heat exchange medium has been developed at Mound. The dry heat exchanger calorimeter is 42 inches high by 18 inches in diameter and the preconditioner is a 22 inch cube, making it extremely compact compared to existing units. The new system is ideally suited for transportable, stand-alone, or glovebox applications. Preliminary tests of the system have produced sample measurements with standard deviations less than 0.25% and sample errors less than 0.50%. These tests have shown that the dry heat exchanger system will yield acceptance data with an accuracy comparable to those of Mound water bath systems now in use. 4 figs., 1 tab.

Renz, D.P.; Wetzel, J.R.; James, S.J.; Kasperski, P.W.; Duff, M.F.

1991-01-01

277

Heat exchangers and method of manufacturing same  

Energy Technology Data Exchange (ETDEWEB)

This patent discloses a heat exchanger such as used in air conditioners and refrigerators, and a method of manufacturing a heat exchanger of brased metal members made mainly of Al or Al alloy. At least one of the brazed metal members is made of a brasing sheet clat with brazing material. The brazed portions of the metal members or the whole surface of the heat exchanger are coated with a corrosion-resistant fluoride flux consisting essentially of 25-40$ KF, 38-54% A1F3 and 3-30% SnF2 by weight, which flux forms a corrosion-inhibiting metallic film. The result is a more durable product and improved maintenance of good heat conductivity, designed for high thermal efficiency.

Haramaki, T.; Shiota, K.; Kokura, S.; Funamoto, T.; Tomita, A.

1987-04-07

278

Solar collector comprising a heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

Solar collector comprising a closed housing of mainly rectangular cross-section, a collector thermally connected to the housing for converting solar rays into heat, a working fluid which, during operation, is partly liquid and partly gaseous, an evaporation space within the housing, a condensation space within the housing, an internal connection between said spaces, and a heat exchanger. An intensive thermal contact between the heat exchanger and the working fluid is obtained by providing the condensation space with a wall profiled inwardly of the housing and forming a space substantially shut off from the surrounding atmosphere, the space being positioned within the outer boundary of the housing but outside the internal portion thereof, and by disposing the heat exchanger within the space and in thermal contact with the wall.

Duncker, M.J.; Kreetz, J.R.

1984-06-19

279

Cylinder for heat exchanger. Cylinder foer vaermevaexlare  

Energy Technology Data Exchange (ETDEWEB)

The invention concerns a hollow cylinder in a scraper heat exchanger for cooling or heating of fluid, half-fluid or highly viscous products. In the cylinder the product is pressed from one end of the cylinder to the other. The product will at the same time be scraped against the cylinder walls, and at that being heated or cooled by means of a medium on the outer face of the cylinder.

Odelstam, C.T.

1986-11-17

280

Heat exchanger with auxiliary cooling system  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger with an auxiliary cooling system capable of cooling a nuclear reactor should the normal cooling mechanism become inoperable. A cooling coil is disposed around vertical heat transfer tubes that carry secondary coolant therethrough and is located in a downward flow of primary coolant that passes in heat transfer relationship with both the cooling coil and the vertical heat transfer tubes. A third coolant is pumped through the cooling coil which absorbs heat from the primary coolant which increases the downward flow of the primary coolant thereby increasing the natural circulation of the primary coolant through the nuclear reactor.

Coleman, John H. (Salem Township, Westmoreland County, PA)

1980-01-01

 
 
 
 
281

Microtube strip heat exchanger. Final technical report  

Energy Technology Data Exchange (ETDEWEB)

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.

Doty, F.D.

1992-07-09

282

Vibration damping in multispan heat exchanger tubes  

International Nuclear Information System (INIS)

Heat exchanger tubes can be damaged or fail if subjected to excessive flow-induced vibration, either from fatigue or fretting-wear. Good heat exchanger design requires that the designer understands and accounts for the vibration mechanisms that might occur, such as vortex shedding, turbulent excitation or fluidelastic instability. To incorporate these phenomena into a flow-induced vibration analysis of a heat exchanger requires information about damping. Damping in multispan heat exchanger tubes largely consists of three components: viscous damping along the tube, and friction and squeeze-film damping at the supports. Unlike viscous damping, squeeze-film damping and friction damping are poorly understood and difficult to measure. In addition, the effect of temperature-dependent fluid viscosity on tube damping has not been verified. To investigate these problems, a single vertical heat exchanger tube with multiple spans was excited by random vibration. Tests were conducted in air and in water at three different temperatures (25, 60, and 90oC). At room temperature, tests were carried out at five different preloads. Frequency response spectra and resonant peak-fitted damping ratios were calculated for all tests. Energy dissipation rates at the supports and the rate of excitation energy input were also measured. Results indicate that damping does not change over the range of temperatures tested and friction damping is very dependent on preload. (author)

1998-01-01

283

Heat exchanger using hydrogen occlusion alloy  

Energy Technology Data Exchange (ETDEWEB)

Concerning powdered hydrogen occlusion alloy, due to its low coefficient of thermal conductivity, dense installation of many fins has been needed in order to receive heat rapidly. In this invention, a tubular heat transfer substance is arranged in a tubular closed mold of elastic material and the outer diameter of the former is smaller than the inner diameter of the latter. Between the inner wall of the mold and the outer wall of the heat transfer substance, the powdered hydrogen occlusion alloy is filled, then all of these are placed in a pressure container and pressure is applied to them with fluid. Through the above method, closed mold, hydrogen occlusion alloy and heat transfer substance are altogether formed in an integrated way. Thus, a heat exchanger which has high heat exchanging efficiency and still maintains the efficiency while it is used for a long time can be obtained. Besides, if many fins are provided along the outer circumference of the tubular heat transfer substance, the heat exchanging efficiency can be further improved and the pulverization of the hydrogen occlusion alloy can be prevented, thus a good effect is shown on maintaining the efficiency for a long time. (21 figs, 1 tab)

Ishikawa, Hiroshi; Oguro, Keisuke; Suzuki, Hiroshi; Kato, Akihiko; Okada, Teruya; Sakamoto, Shizuo

1987-08-29

284

Heat exchanger using hydrogen occlusion alloy  

Energy Technology Data Exchange (ETDEWEB)

Concerning powdered hydrogen occlusion alloy, due to its low coefficient of thermal conductivity, dense installation of many fins has been needed in order to receive heat rapidly. In this invention, a tubular heat transfer substance is arranged in a tubular closed mold of elastic material and the outer diameter of the former is smaller than the inner diameter of the latter. Between the inner wall of the mold and the outer wall of the heat transfer substance, the powdered hydrogen occlusion alloy is filled, then all of these are placed in a pressure container and pressure is applied to them with fluid. Through the above method, closed mold, hydrogen occlusion alloy and heat transfer substance are formed altogether in an integrated way. Thus, a heat exchanger which has high heat exchanging efficiency and still maintains the efficiency while it is used for a long time can be obtained. Besides, by providing many fins on the inner wall of the tubular heat transfer substance, the heat exchanging efficiency can be further improved and the better efficiency of preventing pulverization of the hydrogen occlusion alloy can be achieved. (21 figs, 1 tab)

Ishikawa, Hiroshi; Oguro, Keisuke; Suzuki, Hiroshi; Kato, Akihiko; Okada, Teruya; Sakamoto, Shizuo

1987-08-29

285

Simulation of induction heating process with radiative heat exchange  

Directory of Open Access Journals (Sweden)

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.

A. Kachel; R. Przy?ucki

2007-01-01

286

Design methodology fur multistream plate-fin heat exchangers in heat exchanger networks  

Energy Technology Data Exchange (ETDEWEB)

A newly developed methodology for the design of multistream plate-fin heat exchangers in the optimization of heat exchanger networks is described in detail. The designed heat exchanger consists of several block sections with intermediate entry and exit points along its length, and these sections are determined by the composite curves in the Pinch technology. The requirements of heat transfer and pressure drop are fulfilled through proper surface selection. The methodology was applied to an industrial case study, and the detailed design parameters are given. The example confirms the validity of the suggested methodology. (author)

Wang, L.; Sunden, B.

2001-12-01

287

COUNTER FLOW HEAT EXCHANGERS' IRREVERSIBILITY MINIMIZATION  

Directory of Open Access Journals (Sweden)

Full Text Available The irreversibility minimization method of heat exchanger optimization is extended to include a term to account the exergy of the material of construction of the heat exchanger. The method permits physically realistic optimization to be conducted with the resulting optimum designs providing conceptually beneficial guideposts, which do not change with time or location. Such optima are in contrast to the optima obtained by presently advocated methods, which on onehand indicate unrealistic infinite area of the heat exchangers, and on the other hand point to optima that may change dramatically with location and time. Accompanying exergetic efficiency expressions using the same type of material exergy term show physically more realistic values than the usual expressions.

Abbas Alwi Sakhir Abed

2012-01-01

288

RADIAL DESIGN OXYGENATOR WITH HEAT EXCHANGER  

UK PubMed Central (United Kingdom)

Described is an apparatus (100) for oxygenating and controlling the temperature of blood in an extracorporeal circuit, the apparatus having an inlet (112) and an outlet (109) that is located radially outward from the inlet in order to define a flowpath through the apparatus, the apparatus comprising: a core (120) in communication with the inlet such that blood from a patient can be supplied to the core, the core comprising a first element and a second element that interfit to define openings, wherein the elements and the openings together enhance flow of blood from the patient radially outward from the core a heat exchanger (130) that is arranged about the core and through which blood from the core can move radially outward and an oxygenator (140) that is arranged about the heat exchanger and through which blood from the heat exchanger can move radially outward before exiting the apparatus through the outlet.

CARPENTER WALT; OLSEN ROBERT W; HOBDAY MICHAEL J; MCLEVISH ALFORD L; PLOTT CHRISTOPHER; BRISCOE RODERICK E; CLOUTIER PATRICK J; THAPA ANIL; LI MING; MCINTOSH KEVIN; MERTE KEN

289

High efficiency furnace with secondary heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A domestic forced-air furnace provided with a condensate collector downstream of air moving structure for flowing the products of combustion through the furnace. The furnace includes a secondary heat exchanger. Condensate produced therein is transferred therefrom through the air moving structure to the condensate separator. The secondary heat exchanger and air moving structure are inclined slightly to the horizontal so as to cause continuous flow of condensate therethrough not only during operation of the furnace but also subsequent thereto to assure removal of condensate from the furnace components and thereby avoid corrosive damage thereto from the condensate. The secondary heat exchanger provides the primary pressure drop in the combustion product flow path, permitting control of the furnace capacity by simple modification thereof without the need for changing other components, such as the air moving structure.

Trent, B. O.; Tomlinson, R. S.

1985-09-24

290

Polymer-based heat exchanger desiccant systems  

Energy Technology Data Exchange (ETDEWEB)

The increasing popularity of desiccant-enhanced air conditioning systems has sparked new interest in the search for a better, more efficient desiccant material. The ultimate goal of this research was to develop a material that, when applied to an existing air-to-air heat exchanger, would achieve the necessary heat and mass transfer in a single process, thus transforming a sensible heat exchanger into a total enthalpy exchanger. This study focused on the development and determination of appropriate polymeric desiccant materials for use in different heat and mass transfer systems. The specific objectives for the study were to select an appropriate polymer desiccant, determine the necessary materials properties for this material, and develop and implement mathematical models to analyze the desiccant performance. Two systems were investigated for this study: a rotary wheel total enthalpy exchanger and a fixed plate total enthalpy exchanger. Seven different polymer materials were analyzed to determine the most suitable candidate. Although for the specific conditions studied, the commercial paper-ceramic desiccant out-performed the PVOH materials in both rotary wheel and fixed plate systems, the results suggested that two PVOH materials, PVOH open-cell foam and PVOH/silica gel/molecular sieve composite, have potential for use in total energy exchange applications. By modifying the design conditions, total efficiencies exceeding 70% were achieved for both PVOH foam and PVOH/ceramic composite in rotary wheel systems. In addition, modified the design conditions resulted in total efficiencies greater than 90% for the PVOH foam in both counter-flow and cross-flow flat plate systems. These findings indicated that with appropriate optimization of the exchanger design, these two PVOH materials could have the potential to perform as well as desiccant materials in current rotary wheel and fixed plate exchanger systems.

Staton, J.C.; Howard, J.L.; Scott, E.P.; Kander, R.G.

1999-07-01

291

Intermediate heat exchanger for HTR process heat application  

International Nuclear Information System (INIS)

In the French study on the nuclear gasification of coal, the following options were recommended: Coal hydrogenation, the hydrogen being derived from CH4 reforming under the effects of HTR heat; the use of an intermediate helium circuit between the nuclear plant and the reforming plant. The purpose of the present paper is to describe the heat exchanger designed to transfer heat from the primary to the intermediate circuit.

1979-11-29

292

Numerical Simulation of Passive Residual Heat Removal Heat Exchanger  

International Nuclear Information System (INIS)

FLUENT software was employed to simulate the temperature-field and flow-field of AP1000 passive residual heat removal heat exchanger (PRHR HX), and investigate its heat-transferring and flow characteristics. Through comparative analysis of the distributions of temperature-field and flow-field in different locations at the same time, and the variations of temperature-field and flow-field in the same location at different time, heat-transferring process and natural convection situation of PRHR HX were understood deeply. It contributes to analyze the natural circulation capacity of PRHR HX, and provides some references for the effective operation of passive residual heat removal system. (authors)

2010-01-01

293

Dynamic simulation of plate heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The dynamic response of a parallel plate heat exchanger to a step input of the hot fluid temperature is studied and evaluated. The temperature profiles along the channels and in the outlets are simulated by using a ``Cinematic Model``. The experimental and numerical results for both dynamic and steady-state temperature profiles are compared and a general computer program based on finite differences is introduced for all kinds of PHEs. The applied PHE is a 5-plate, 2-fluid, looped U-flow heat exchanger, in which the fluids in adjacent channels flow in a counter-current direction.

Sharifi, F.; Narandji, M.R.G.; Mehravaran, K. [Amir-Kabir Univ. of Technology, Tehran (Iran, Islamic Republic of)

1995-03-01

294

Heat exchanger containing a component capable of discontinuous movement  

Energy Technology Data Exchange (ETDEWEB)

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.

Wilson, David Gordon (Winchester, MA)

2002-01-01

295

Heat exchanger containing a component capable of discontinuous movement  

Energy Technology Data Exchange (ETDEWEB)

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.

Wilson, David G. (Winchester, MA)

1993-01-01

296

Heat exchanger design for desalination plants  

International Nuclear Information System (INIS)

[en] The Office of Saline Water (OSW) accomplished a very large amount of significant work related to the design and performance of large heat exchanger bundles and enhanced heat transfer surfaces. This work was undertaken to provide basic technical and economic data for the design of distillation plants for the desalination of seawater, and should be of value to other industrial applications as well. The OSW work covers almost every aspect of heat exchanger design, and ranges academic research to data gathering on commercial desalting plants. Exchanger design configurations include multistage flash plant condensers, vertical tube falling film and upflow evaporators, and horizontal tube spray film evaporators. Unfortunately, the data is scattered through a large number of reports of which many are concerned primarily with factors other than heat transfer, and the quality of reporting and the quality of the data are far from consistent. This report catalogues and organizes the heat exchanger data developed by the OSW. Some analysis as to the validity of the data is made and ranges of performance that can be expected are given. Emphasis is placed on the vertical tube, falling film evaporators. A thorough analysis of the large literature file that was surveyed was not possible. No analysis was made of the quality of original data, but apparent data discrepancies are pointed out where such discrepancies happen to be found

1979-01-01

297

Carbon nanotube heat-exchange systems  

Energy Technology Data Exchange (ETDEWEB)

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).

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

2008-11-11

298

Heat exchanger and the associated pipe  

International Nuclear Information System (INIS)

A heat exchanger is described in which the pipe or pipes consist of two or more adjacent, concentric layers. For every two adjacent layers, the outer surface of the inner layer and the inner surface of the outer layer are cladded with a thin layer or layers of a fairly soft material with good heat conducting properties. This soft material can be pure metal or a paste. (T.P.)

1979-01-01

299

Space HVAC systems and the role of heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Although heat exchangers are among the most important components constituting space HVAC systems, more than 50 of the systems examined were showing defects and malfunctions which in most cases were found with the heat exchanger area. The paper therefore focuses on data and facts concerning the uses and designs of heat exchangers and demonstrates their optimal operation in accordance with their individual uses and fields of application. Photographs and drawings facilitate access to conventional (spiral), lamellar, flat plate and tubular heat exchangers. Detailed descriptions are given of U-tube heat exchangers, fixed-tube heat exchangers, special connection tubular heat exchangers, coaxial heat exchangers and volume-dependent flat plate heat exchangers. Space HVAC systems keep on developing. Manufacturers will have to be prepared for pressing costs, requirements as to the systems' quality, requirements as to the cleaning and corrosion resistance of the systems. (HWJ).

Vries, H. de.

1987-05-01

300

Controller apparatus and method for heat exchange system  

Energy Technology Data Exchange (ETDEWEB)

A controller for use with two or more heat exchange systems in which each system includes first and second heat exchangers, a working fluid circuit between the heat exchangers of each system and a working fluid in the circuit, is described comprising: (a) means manifolding together the outputs of the working fluid circuits for all of the first heat exchangers for all of the heat exchange systems and providing an input from the manifolding means to all of the second heat exchangers for all of the heat exchange systems; and (b) means for controlling the flow of the working fluid from each of the first heat exchangers dependent upon the average energy demand for all of the second heat exchangers.

Hayes, J.H.

1988-01-05

 
 
 
 
301

Condensation and frost formation in heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

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.

Rostami, A.A.

1982-01-01

302

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

1982-01-01

303

Heat Exchanger for Motor Vehicle Cooling System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 co...

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

304

Heat Exchange After Atropine and Pralidoxime Administration.  

Science.gov (United States)

This report summarizes a tightly controlled laboratory study in which the effects of intramuscular saline (control), atropine (2 mg), and/or pralidoxime (600 mg) on heat exchange were evaluated in four healthy males during seated, cycle exercise in a temp...

B. S. Cadarette L. A. Stephenson M. A. Kolka R. R. Gonzalez

1986-01-01

305

Feedback linearisation of a heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

The main contribution of the paper is to provide an explicit necessary and sufficient conditions for the system to be locally linearisable in terms of parameters of the heat exchanger model. Examples illustrate how the controllability issues which are standard in linear system theory can be naturally extended to the nonlinear system model via the linearising transformation.

Rahman, M.H.R.F.; Devanathan, R. Sr. [Nanyang Technological Univ. (Singapore)

1994-12-31

306

Improvements relating to plate heat exchangers  

International Nuclear Information System (INIS)

A plate heat exchanger is described in which the whole pack of plates can be removed bodily from the containing frame for maintenance. The advantages of such a system to the nuclear industry in particular include the saving of time, the avoidance of disturbing connecting pipework and the possibility of carrying out plate maintenance remotely from the installation. (U.K.).

1981-01-01

307

Energy saving heat exchanger reactor at DSM  

Energy Technology Data Exchange (ETDEWEB)

The (semi-) continuous production of intermediates in a heat exchanger (HEX) reactor appears to be an attractive alternative for the batch-wise handling of potentially dangerous exothermic reactions. The pilot installation shows that the HEX reactor is an interesting new technology for producing intermediates faster and inherently safer than in the currently used batch reactors.

Moreau, J. [DSM Research Campus, Geleen (Netherlands)

2003-06-01

308

Cooling device for a heat exchange fluid  

International Nuclear Information System (INIS)

[en] The invention refers to a system for cooling process or operation fluids, in which the local or general superheating of the coolant must be avoided. It particularly applies to the bleed fluid of a nuclear power station steam generator. This invention aims to create a heat exchange system that uses static components only and that is therefore completely reliable whilst remaining simple and relatively economical. This system includes a regeneration heat exchanger (with a primary and secondary system) and a triple flow heat exchanger with three circuits. The first and second circuits are in fluid communication with the primary and secondary circuits of the regeneration heat exchanger. The fluid communication between the regeneration heat exchanger and the triple circuit heat exchanger is such that the process fluid first goes through one of the circuits of the regeneration heat exchanger where it is cooled, then through one of the first two circuits of the triple circuit heat exchanger where it is cooled still more, then through the other of the circuits of the regeneration exchanger where it is heated and finally through the second of the first two circuits of the triple circuit heat exchanger where it is cooled again. A coolant flows through the third circuit in order to cool the process fluid concerned[fr] L'invention se rapporte a un dispositif destine au refroidisseent des fluides de processus ou d'operation, dans lequel la surchauffe localisee ou generale du fluide de refroidissement doit etre evitee. Elle s'applique particulierement au cas du fluide de purge du generateur de vapeur d'une centrale nucleaire. L'objet de l'invention est de creer un dispositif d'echange thermique qui utilise uniquement des composants statistiques et qui, par suite, est parfaitement fiable tout en restant simple et relativement economique. Ce dispositif comprend un echangeur thermique a regeneration (ledit echangeur thermique presentant un circuit primaire et un cricuit secondaire), et un echangeur thermique a triple flux comprenant trois circuits. Le premier et le deuxieme circuit sont en communication fluide avec le circuit primaire et le circuit secondaire de l'echangeur thermique a regeneration. La communication fluide entre l'echangeur de chaleur a regeneration et l'echangeur de chaleur a triple circuit est telle que le fluide de processus passe d'abord dans l'un des circuits de l'echangeur thermique a regenration ou il est refroidi, ensuite dans l'un des deux premiers circuits de l'echangeur thermique a triple circuit ou il est refroidi davantage, puis dans l'autre des circuits dudit echangeur a regeneration ou il est rechauffe, et enfin a travers l'autre des deux premiers circuits de l'echangeur thermique a triple circuit ou il se trouve refroidi a nouveau. Un fluide de refroidissement passe dans le troisieme circuit afin de refroidir ledit fluide de processus

1975-05-15

309

Heat exchangers for waste heat recovery; Waermetauscher zur Abwaermenutzung  

Energy Technology Data Exchange (ETDEWEB)

The study discusses heat recovery by means of heat exchangers. Heat exchanger fluids may be water, air, flue gas, and thermo-oil, but the data presented here can also applied to other liquid or gaseous media. The thermodynamic aspects are gone into only as far as they are necessary for understanding. There are two different types of heat transfer: First, indirect heat transfer: The two fluids are separate, the spatial conditions are independent of time (recuperative heat exchangers). Secondly, semi-indirect heat transfer: Periodic interaction of the two fluids in a single compartment, with time-dependent spatial conditons. The heat of the primary fluid is stored by the compartment walls and then transferred to the secondary fluid (regenerative heat exchangers). (orig./GL) [Deutsch] caese Studie muss sich auf die Hauptbereiche der Waermerueckgewinnung mittels Waermetauscher beschraenken. Bei den Medien im Waermetauscher wird vor allem auf Wasser, Luft, Rauchgase und Thermooel eingegangen. Die getroffenen Aussagen sind aber meist auch auf andere fluessige oder gasfoermige Medien uebertragbar. Die thermodynamischen Zusammenhaenge koennen hier nur soweit erlaeutert werden, wie es zum Verstaendnis der Ergebnisse dieser Studie notwendig ist. Bezueglich des Verhaltens der beiden Stoffstroeme zueinander ist zu unterscheiden zwischen: - Indirekte Waermeuebertragung: Die beiden Medien sind raeumlich voneinander getrennt, die raeumlichen Verhaeltnisse sind von der Zeit unabhaengig (Prinzip der rekuperativen Waermetauscher). - Halbindirekte Waermeuebertragung: Periodische Wechselwirkung der beiden Medien in einem Raum, die raeumlichen Verhaeltnisse sind von der Zeit abhaengig. Die Waerme des primaeren Mediums wird von der Berandung des Raumes gespeichert und spaeter an das sekundaere Medium abgegeben (Prinzip der regenerativen Waermetauscher). - Direkte Waermeuebertragung: Die beiden Stoffstroeme beruehren sich in einem Raum, beispielsweise die Direkterwaermung von Ziegelsteinen durch Rauchgase im Tunnelofen einer Ziegelei. In dieser Arbeit werden die indirekte und die halbindirekte Waermeuebertragung mittels Regeneratoren und Rekuperatoren behandelt. (orig./GL)

Kuhn, S. [Muenzer Kuhn Leis Ingenieurgesellschaft mbH, Muenchen (Germany); Kuhn, H. [Muenzer Kuhn Leis Ingenieurgesellschaft mbH, Muenchen (Germany); Roehrl, W. [Muenzer Kuhn Leis Ingenieurgesellschaft mbH, Muenchen (Germany); Leis, U. [Muenzer Kuhn Leis Ingenieurgesellschaft mbH, Muenchen (Germany); Muenzer, T. [Muenzer Kuhn Leis Ingenieurgesellschaft mbH, Muenchen (Germany)

1994-11-01

310

Heat pump heating with ambient air heat exchanger. Waermepumpenheizung mit Umgebungsluft-Waermetauscher  

Energy Technology Data Exchange (ETDEWEB)

The purpose of the invention is to develop a heat pump heating system with ambient air heat exchanger, so that the plates of the heat exchanger have parallel flow over them of moving ambient air, without any additional drive. According to the invention, this problem is solved by the plate register being able to rotate around a vertical axis like a weather vane, and by the absorption plates of the plate register setting themselves automatically parallel to the direction of flow of the ambient air. This leads to a considerable increase in the efficiency of the ambient air heat exchanger and therefore of the heat pump heating system at little expense. (HWJ).

Dietrich, B.; Kimpenhaus, W.

1984-04-12

311

Materials development for HTGR heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Some versions of the HTGR generate high primary coolant gas temperatures (850/sup 0/ to 950/sup 0/C) and exchange this heat, through intermediate heat exchangers (IHX's), to a secondary loop for higher temperature process heat applications. Although IHX's for these systems are typically pressure-balanced (low-stress) units, their design involves several challenges, including the potential interactions between structural materials and impurities present in the HTGR primary coolant. Considerable work is required to qualify materials for IHX applications, including detailed mechanical property characterization, determination of environmental influences on performance, provision of welding materials and procedures for producing joints of adequate strength and integrity, and provisions for wear protection. Some of the work currently under way addressing these issues is described.

Johnson, W.R.; Roberts, D.I.

1982-07-01

312

Heat exchangers with several heat exchanger matrices mounted in a common casing for separately conducted media  

International Nuclear Information System (INIS)

The heat exchanger is suited for plants with a closed gas cycle such as, e. g., HTR with a helium turbine or drive units for vehicles. It contains heat exchanger matrices running parallel to each other and formed by the folds of a uniformly folded band and by walls covering the saddles of the folds. Two neighbouring matrices each are combined to form a heat exchanger unit and supported between supporting walls. The heat exchanger unit is not firmly connected with these supporting walls and therefore can easily to be inserted or dismounted. For sealing purposes, the fold saddles are contacting the supporting walls because of the high pressure of the meUWIdium, Ior the remaining seals between hp and lp-compartments labyrinth boxes being provided. (UWI)

1979-01-01

313

Triple loop heat exchanger for an absorption refrigeration system  

Energy Technology Data Exchange (ETDEWEB)

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.

Reimann, Robert C. (Lafayette, NY)

1984-01-01

314

Air duct heat exchanger; Luftkanal-Waermetauscher  

Energy Technology Data Exchange (ETDEWEB)

A mechanical building ventilation unit that brings together two functions - fluid transport and heat recovery - is presented. Aluminium fins in the supply air duct and in the adjacent extract air duct increase the heat flow from fluid to fluid. This unit is mainly intended to be used for residential ventilation and was investigated by means of experiments and simulations. Air flow rates, temperatures, air humidities and pressure differences were measured in an experimental set-up. Additionally, using a program for two-dimensional heat conduction analyses and a simple model, the efficiency of the heat recovery was calculated and compared with measurements. Afterwards, the influence of variations of the heat exchanger geometry was investigated by means of simulations. It was shown that by using this concept, it is possible to realise a ventilation unit in which heat is exchanged with high efficiency, e.g. temperature efficiency of 0.7 at a duct length of 6 m. At the same time, low pressure-drops occur, typically 20 Pa, which leads to low rates of electrical energy input. (author)

Huber, H.; Helfenfinger, D. [Berner Fachhochschule, Hochschule fuer Technik und Architektur (HTA), Lucerne (Switzerland); Manz, H. [EMPA Eidgenoessischen Materialpruefungs- und Forschungsanstalt, Duebendorf (Switzerland)

2000-07-01

315

Preliminary SP-100/Stirling heat exchanger designs  

Energy Technology Data Exchange (ETDEWEB)

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.

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

316

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.

1993-01-01

317

Preliminary SP-100/Stirling heat exchanger designs  

International Nuclear Information System (INIS)

[en] 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

1994-01-01

318

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

International Nuclear Information System (INIS)

[en] 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)

2003-01-01

319

Heat exchanger applied to the farm-produce industry  

UK PubMed Central (United Kingdom)

The subject of the present invention is a heat exchanger for the exchange between a liquid and a (heating or refrigerating) heat-exchange fluid consisting of at least on enclosure in which heat-exchange elements are arranged. It is characterised by the fact that the said elements consist of embossed plates 1, 2 formed by the superposition of metal sheets between which the embossing creates flow tubes, a heat-exchange fluid flowing in each of the tubes of each of the plates, the liquid being made to flow along the exchange surfaces of the said plates 1, 2.

320

Production capacity increased 65% using plate heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Heat exchangers used to cool polyurethane monomer were limiting production capacity and were a source of high maintenance costs at the Curon Division of Reeves Bros., Inc. in Cornelius, NC. In 1980, Reeves Bros. began replacing the existing heat exchangers with paraflow plate heat exchangers. To date, three plate exchangers have been installed. Since installation of the heat exchangers, maximum cooling has been increased by 65%. No maintenance has been required on the units, and floor space required for the heat exchangers has been reduced by about 2/3.

Sherrill, J.

1983-08-01

 
 
 
 
321

Regenerative heat exchangers; viewpoints on the available materials  

Energy Technology Data Exchange (ETDEWEB)

Aluminium has become a widely applied material for heat exchangers. However, the use of aluminium has both advantages and disadvantages (corrosion at low and high pH values). The possibility of using other materials for rotary heat exchangers is also discussed. A comparison is made between heat exchangers with aluminium and heat exchangers with non-metallic exchange surfaces. Long-time tests with heat exchangers with ceramic material have had very positive results with respect to corrosion, acid and alkaline resistance and adaptability for high temperatures and aggressive environments. 2 figs., 1 tab., 4 refs.

Haellgren, K.; Knorr, K.T.; Wijnstra, K.P.

1987-04-01

322

RECITAL SCRUTINY ON TUBE-INTUBE COMPACT HEAT EXCHANGERS  

Directory of Open Access Journals (Sweden)

Full Text Available This paper focused on the investigational cram of the recital characteristics of tube-in-tube compact heat exchangers. Experiments are conducted in the compact heat exchangers with R-134a and liquefiedpetroleum gas. The effectiveness of the heat exchangers was calculated using the experiment data and it was found that the effectiveness of heat exchanger-1 is above 75 and heat exchanger-2 is above 84% for R-134a.The effectiveness of heat exchanger-1 is about 60% and heat exchanger-2 is about 81% for liquefied petroleum gas. In this paper, details about the new tube-in-tube type compact heat exchanger, experimental setup, results and conclusions are discussed.

V.NATARAJAN,; DR.P.SENTHIL KUMAR

2011-01-01

323

14 CFR 23.1125 - Exhaust heat exchangers.  

Science.gov (United States)

... 2010-01-01 2010-01-01 false Exhaust heat exchangers. 23.1125 Section 23.1125 Aeronautics and...Powerplant Exhaust System § 23.1125 Exhaust heat exchangers. For reciprocating engine powered airplanes...

2010-01-01

324

14 CFR 25.1125 - Exhaust heat exchangers.  

Science.gov (United States)

... 2010-01-01 2010-01-01 false Exhaust heat exchangers. 25.1125 Section 25.1125 Aeronautics and...Powerplant Exhaust System § 25.1125 Exhaust heat exchangers. For reciprocating engine powered airplanes,...

2010-01-01

325

14 CFR 29.1125 - Exhaust heat exchangers.  

Science.gov (United States)

... 2010-01-01 2010-01-01 false Exhaust heat exchangers. 29.1125 Section 29.1125 Aeronautics and...Powerplant Exhaust System § 29.1125 Exhaust heat exchangers. For reciprocating engine powered rotorcraft...

2010-01-01

326

Optimizing heat exchanger design for crude oil stabilization  

Energy Technology Data Exchange (ETDEWEB)

The plate heat exchanger is used for heat recovery applications involving cooling of glycol or fresh water with sea water aboard offshore platforms and other modular constructions. Plate heat exchangers are rugged enough for both offshore and onshore crude oil heat transfer operations. The economics of heat recovery are highly favorable in a crude oil treatment plant when using a plate heat exchanger. By modifying the equipment layout, the plant operator can achieve minimum operating and maintenance costs while achieving a high degree of heat recovery at quite reasonable capital costs with a plate heat exchanger.

Wagner, R.L.; Sjogren, S.

1985-02-01

327

Heat transfer enhancement in medium temperature thermal energy storage system using a multitube heat transfer array  

Energy Technology Data Exchange (ETDEWEB)

An experimental energy storage system has been designed using an horizontal shell and tube heat exchanger incorporating a medium temperature phase change material (PCM) with a melting point of 117.7 C. Two experimental configurations consisting of a control unit with one heat transfer tube and a multitube unit with four heat transfer tubes were studied. The thermal characteristics in the systems have been analysed using isothermal contour plots and temperature time curves. Temperature gradients along the three directions of the shell and tube systems; axial, radial and angular directions have been analysed and compared. The phase change in the multitube system was dominated by the effect of convective heat transfer compared to conductive heat transfer in the control system. The temperature gradient in the PCM during phase change was greatest in the radial direction for both the control and multitube systems. The temperature gradients recorded in the axial direction for the control and multitube systems during the change of phase were respectively 2.5 and 3.5% that of the radial direction, indicating essentially a two-dimensional heat transfer in the PCM. The onset of natural convection through the formation of multiple convective cells in the multitube system significantly altered the shape of the solid liquid interface fluid flow and indicates the requirement for an in-depth study of multitube arrangements. (author)

Agyenim, Francis; Smyth, Mervyn [Centre for Sustainable Technologies, Ulster University, Newtownabbey BT37 0QB (United Kingdom); Eames, Philip [Electronic and Electrical Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

2010-01-15

328

Analysis of Heat Transfer Enhancement in Spiral Plate Heat Exchanger  

Directory of Open Access Journals (Sweden)

Full Text Available In the present study, the heat transfer coefficients of benzene in a spiral plate heat exchanger are investigated. The test section consists of a Plate of width 0.3150 m, thickness 0.001 m and Mean hydraulic diameter of 0.01 m. The mass flow rate of water (Hot fluid) is varying from 0.5 kg sec-1 to 0.8 kg sec-1 and the mass flow rate of benzene (cold fluid) varies from 0.4 kg sec-1 to 0.7 kg sec-1. Experiments have been conducted by varying the mass flow rate, temperature and pressure of cold fluid, keeping the mass flow rate of hot fluid constant. The effects of relevant parameters on spiral plate heat exchanger are investigated. The data obtained from the experimental study are compared with the theoretical data. Besides, a new correlation for the nusselt number which can be used for practical applications is proposed.

Kaliannan Saravanan; Rangasamy Rajavel

2009-01-01

329

Preliminary thermal sizing of intermediate heat exchanger for NHDD system  

Energy Technology Data Exchange (ETDEWEB)

Nuclear Hydrogen Development and Demonstration (NHDD) system is a Very High Temperature gascooled Reactor (VHTR) coupled with hydrogen production systems. Intermediate heat exchanger transfers heat from the nuclear reactor to the hydrogen production system. This study presented the sensitivity analysis on a preliminary thermal sizing of the intermediate heat exchanger. Printed Circuit Heat Exchanger (PCHE) was selected for the thermal sizing because the printed circuit heat exchanger has the largest compactness among the heat exchanger types. The analysis was performed to estimate the effect of key parameters including the operating condition of the intermediate system, the geometrical factors of the PCHE, and the working fluid of the intermediate system.

Kim, Chan Soo; Hong, Sung Deok; Kim, Yong Wan; Chang, Jongh Wa [KAERI, Daejeon (Korea, Republic of)

2009-07-01

330

Preliminary thermal sizing of intermediate heat exchanger for NHDD system  

International Nuclear Information System (INIS)

Nuclear Hydrogen Development and Demonstration (NHDD) system is a Very High Temperature gascooled Reactor (VHTR) coupled with hydrogen production systems. Intermediate heat exchanger transfers heat from the nuclear reactor to the hydrogen production system. This study presented the sensitivity analysis on a preliminary thermal sizing of the intermediate heat exchanger. Printed Circuit Heat Exchanger (PCHE) was selected for the thermal sizing because the printed circuit heat exchanger has the largest compactness among the heat exchanger types. The analysis was performed to estimate the effect of key parameters including the operating condition of the intermediate system, the geometrical factors of the PCHE, and the working fluid of the intermediate system.

2009-01-01

331

Compact heat exchanger optimization tools based on volume averaging theory  

Energy Technology Data Exchange (ETDEWEB)

Optimization of the enhancement of heat exchangers (HE), compact heat exchangers (CHE) and micro-heat exchangers by design of their basic structure is the focus of this work. A theoretical basis for heat and momentum transport equations obtained with volume averaging theory (VAT) is developed for modeling and design of heat exchangers. Using different flow regime transport models, equation sets are obtained for momentum transport and two-temperature or three-temperature heat transfer in non-isotropic heterogeneous CHE media that account for interphase exchange and micro-roughness.

Travkin, V.S.; Catton, I.

1999-07-01

332

Diamond wire cutting of heat exchangers  

International Nuclear Information System (INIS)

With the change-out of equipment at nuclear power plants comes large quantities of low level contaminated metallic waste. Of particular concern are large heat exchangers, preheaters and steam generators. These bulky items consume huge volumes of burial space. The need for volume reduction and recycling of these metals has created new demands for 'how' to cut heat exchangers into useful sizes for decontamination, melting or compaction. This paper reviews the cutting solution provided by a diamond wire system, with particular regard for cutting of a Ringhals Preheater Bundle at Studsvik Nuclear in 1989. The background of diamond wire sawing is discussed and basic components of wire sawing are explained. Other examples of wire cutting decommissioned components are also given. (author)

1991-01-01

333

Materials development for HTGR heat exchangers  

International Nuclear Information System (INIS)

High-temperature, gas-cooled reactors (HTGR's) are uranium/thorium-fueled, graphite-moderated, helium-cooled systems capable of producing high-temperature primary coolant. Several variants of this system are under active development in the United States and worldwide. In one version, the primary coolant heat is transferred to steam generators producing 5380C/16.5 MPa steam for use in electricity generation or process heat applications. The materials and design technology for steam generators in this system are well developed, relying heavily upon prior experience with fossil-fired steam generators and the steam generators of the commercial HTGR's. The major work that remains to be done is to complete qualification of the materials and to respond to evolving rules pertinent to elevatedtemperature nuclear design and construction. Other versions of the HTGR generate much higher primary coolant gas temperatures (8500 to 9500C) and exchange this heat, through intermediate heat exchangers (IHX's), to a secondary loop for higher temperature process heat applications. Although IHX's for these systems are typically pressure-balanced (low-stress) units, their design involves several challenges, including the potential interactions between structural materials and impurities present in the HTGR primary coolant. Considerable work is required to qualify materials for IHX applications, including detailed mechanical property characterization, determination of environmental influences on performance, provision of welding materials and procedures for producing joints of adequate strength and integrity, and provisions for wear protection. Some of the work currently under way addressing these issues is described.

1983-01-01

334

Measuring thermal characteristics of the heat exchanger  

Directory of Open Access Journals (Sweden)

Full Text Available New Technologies Research Centre at the University of West Bohemia in Pilsen uses middle-sized wind tunnel experimental facility. The tunnel equipment is extended in order to let us measure also heat transfer: the main wind tunnel duct itself forms the opened cooling air circuit, one closed circuit is there for water based coolant ?ow and one more closed circuit forms the hot compressed air loop. In this article, the typical measurement of the thermal characteristics of the common waterair heat exchanger is presented.

K?ourek Jind?ich; K?s Michal; Syka Tomáš

2012-01-01

335

Performance monitoring of heat exchanger surfaces  

Energy Technology Data Exchange (ETDEWEB)

To monitor the performance of a heat exchanger assembly, the fin efficiency and fin effectiveness (isolated fin), and enhancement factor and augmentation factor (assembly) are commonly used. In certain cases the augmentation factor may not give all the information concerning the behavior of the assembly. An assembly efficiency is proposed which appears to overcome this deficiency. The discussion centers upon a rectangular fin assembly and compares the new indicator with existing indicators.

Malik, M.Y.; Wood, A.S.

1999-07-01

336

Device for closing defective heat exchanger tubes  

International Nuclear Information System (INIS)

[en] This is a device for closing defective heat exchanger tubes in the tube plate region. A metallic plug with a central bore containing a blasting charge and a primer is introduced into the defective tube by explosion welding. (RW)[de] Es wird eine Einrichtung zum Verschliessen schadhafter Waermetauscherrohre im Bereich des Rohrbodens angegeben. Dabei wird mit Hilfe der Explosionsschweisstechnik ein metallischer Verschlussstopfen, der in einer zentralen Bohrung mit Sprengladung und Zuendkapsel versehen ist, in das defekte Rohr eingefuehrt. (RW)

1977-01-01

337

An analysis of heat exchanger tube plugs  

Energy Technology Data Exchange (ETDEWEB)

This paper examines the use of mechanical contact plugs to seal off leaking tubes in the intermediate heat exchanger of a liquid metal fast breeder reactor. Finite element models are used to study two different types of plugs. Although the analysis deals with the installation of the plugs, the primary emphasis is on the ability of the plugs to withstand the effects of a duty cycle.

Karabin, M.E.; Heylmun, N.F.

1982-01-01

338

Optimizing PT Arun LNG main heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

The capacity of a LNG liquefaction unit has been increased by upgrading the refrigeration system, without making changes to the main heat exchanger (MHE). It is interesting, that after all modifications were completed, a higher refrigerant circulation alone could not increase LNG production. However, by optimizing the refrigerant component ratio, the UA of the MHE increased and LNG production improved. This technical evaluation will provide recommendations and show how the evaluation of the internal temperature profile helped optimize the MHE operating conditions.

Irawan, B. [PT Arun NGL Co., Sumatra (Indonesia)

1995-12-01

339

EXPERIMENTAL INVESTIGATION OF INSERTION MODELS INTENSIFYING HEAT EXCHANGE  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents the analysis of influence of rotating insertion models upon the intensification of heat exchange in double-pipe heat exchanger. The test stand and the method of measurement are given. On the basis of measurement results the effectiveness of heat exchange estimation has also been presented.

Tadeusz Fodemski; Bogumi? Staniszewski

1978-01-01

340

Investigation into fouling of a printed circuit heat exchanger.  

Science.gov (United States)

A facility has been built to compare the fouling propensity of two heat exchangers operating with cooling water from an open cooling tower. Tests were carried out with a Printed Circuit Heat Exchanger and a heat exchanger having tube dimensions representa...

1991-01-01

 
 
 
 
341

Heat exchanger support apparatus in a fluidized bed  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger is mounted in the upper portion of a fluidized combusting bed for the control of the temperature of the bed. A support, made up of tubes, is extended from the perforated plate of the fluidized bed up to the heat exchanger. The tubular support framework for the heat exchanger has liquid circulated therethrough to prevent deterioration of the support.

Lawton, Carl W. (West Hartford, CT)

1982-01-01

342

New plates for different types of plate heat exchangers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The first patent for a plate heat exchanger was granted in 1878 to Albretch Dracke, a German inventor. The commercial embodiment of these equipments has become available in 1923. However, the plate heat exchanger development race began in the 1930’s and these gasketed plate and frame heat exchangers...

Fernandes, Carla S.; Dias, Ricardo P.; Maia, João M.

343

Corrosion Problems for Heat Exchangers of Pressurized Water Reactors.  

Science.gov (United States)

Heat exchangers are used between the primary and the secondary circuits of PWR-PHWR. The various corrosion types and the types of heat exchangers are described with the well-known corrosion regions in them. Corrosion defects in the heat exchangers are inv...

B. Tugrul H. Yavuz

1985-01-01

344

Heat transfer and pressure loss of immediate heat exchanger  

International Nuclear Information System (INIS)

The immediate heat exchanger (IHX) is the key component to connect the high-temperature gas-cooled reactor with the helium turbine for high-temperature gas-cooled reactor coupled with indirect gas turbine cycle (indirect HTGR-GT) system. IHX transfers the high temperature energy generated by reactor to gas turbine loop. IHX can reduce the difficulties of the design,operation and maintenance of helium gas turbine. On the other hand, IHX will lower the cycle efficiency due to IHX's heat transfer and pressure loss. So the characteristics of heat transfer and pressure loss,material performance, compactness should be considered for the design and the choice of IHX because of its special operating conditions. The features of printed circuit heat exchanger (PCHE) and its feasibility in the indirect HTGR-GT were discussed. The characteristics of heat transfer and pressure loss of the PCHE were studied and the factors effecting heat transfer efficiency and pressure loss were analyzed. Furthermore, the measures to improve the performance of the IHX were presented. (authors)

2009-01-01

345

Cutting method for heat exchanger contaminated with radioactivity  

International Nuclear Information System (INIS)

Cutting operation for heat exchangers contaminated with radioactivity, especially, heat transfer pipes in a nuclear power plant is facilitated. That is, fillers are charged to the inside of heat exchangers and they are solidified to fix the heat transfer pipes etc. at the inside thereof. Then they are cut. With such procedures, contaminates are kept in the inside of the heat exchangers. Further, the cutting operation for the heat transfer pipes of the heat exchangers can be conducted with shells in the same way as that for integral structures. Further, since contaminates are not diffused upon cutting operation, operators' radiation dose can be reduced. (I.S.)

1989-09-28

346

Calculation of 'experimental' convective heat transfer coefficient under stepwise periodic time variation of heat exchange intensity  

International Nuclear Information System (INIS)

[en] The earlier developed method of calculating averaged heat transfer in heat exchange processes with periodic intensity is summarized for the case of stepwise time law of heat exchange intensity variation. Approximated analytical solution is obtained

1991-01-01

347

Graphite Foam Heat Exchangers for Thermal Management  

Energy Technology Data Exchange (ETDEWEB)

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.

Klett, J.W.

2004-06-07

348

Management techniques of the JRR-4 heat exchanger  

International Nuclear Information System (INIS)

[en] After JRR-4 heat exchanger was renewed in made of stainless steel from carbon steel, it was examined how to manage the heat exchanger. The main subject is the cleaning technology of the heat exchanger. The recovery of old heat exchanger cooling performance has been by only chemical cleaning. Now we use chemical and dry cleaning as a new technique. It helps prevent of corrosions of secondary pipes and reduce of management costs. This report describes the performance management and cleaning technology of the JRR-4 heat exchanger and the management of the JRR-4 coolant. (author)

2005-01-01

349

Heat transfer enhancement in heat exchangers by longitudinal vortex generators  

International Nuclear Information System (INIS)

In this paper heat transfer enhancement and flow losses are computed for the interaction of a laminar channel flow with a pair of counterrotating longitudinal vortices generated by a pair of delta-winglets punched out of the channel wall. The geometry simulates an element of a fin-plate or fin-tube heat exchanger. The structure of the vortex flow and temperature distribution, the local heat transfer coefficients and the local flow losses are discussed for a sample case. For a Reynolds number of Red = 1000 and a vortex generator angle of attack of ? = 25 degrees heat transfer is enhanced locally by more than 300% and in the mean by 50%. These values increase further with Re and ?

1990-01-01

350

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

CERN Multimedia

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...

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

2012-01-01

351

AUTOMATIC EVOLUTION OF HEAT EXCHANGER NETWORKS WITH SIMULTANEOUS HEAT EXCHANGER DESIGN  

Directory of Open Access Journals (Sweden)

Full Text Available Recently, a new software (AtHENS) that automatically synthesizes a heat exchanger network with minima consumption of utilities was developed. This work deals with the next step, which represents the evolution of the initial network. Hence, new procedures to identify and break loops are incorporated, for which a new algorithm is proposed. Also, a heat exchanger design procedure which uses the available pressure drop to determine the film coefficient on the tube side and shell side is added, providing the utilization of more realistic heat exchangers in the network during its optimization. Results obtained from a case study point to the possibility of equipment design having a strong influence on the network synthesis.

F.S. LIPORACE; F.L.P. PESSOA; E.M. QUEIROZ

1999-01-01

352

AUTOMATIC EVOLUTION OF HEAT EXCHANGER NETWORKS WITH SIMULTANEOUS HEAT EXCHANGER DESIGN  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Recently, a new software (AtHENS) that automatically synthesizes a heat exchanger network with minima consumption of utilities was developed. This work deals with the next step, which represents the evolution of the initial network. Hence, new procedures to identify and break loops are incorporated, for which a new algorithm is proposed. Also, a heat exchanger design procedure which uses the available pressure drop to determine the film coefficient on the tube side and sh (more) ell side is added, providing the utilization of more realistic heat exchangers in the network during its optimization. Results obtained from a case study point to the possibility of equipment design having a strong influence on the network synthesis.

LIPORACE, F.S.; PESSOA, F.L.P.; QUEIROZ, E.M.

1999-03-01

353

Integrated heat exchangers for a nuclear reactor  

International Nuclear Information System (INIS)

[en] With the aim of reducing the diameter of the vessel of a liquid sodium cooled nuclear reactor, the lower ends of the intermediate exchangers, placed vertically and entirely contained in the vessel, rest on the core support, on its periphery. These exchangers are connected to the secondary sodium systems by pipes crossing through the upper shield of the vessel, and the large revolving plug includes an opening of a size commensurate with the dimensions of the cross sections of the intermediate exchangers, placed at a distance from the rotation axis of the revolving plug, enabling this opening to be brought vertically over each heat exchanger in turn, by rotating the plug[fr] Dans le but de reduire le diametre de la cuve d'un reacteur nucleaire refroidi au sodium liquide les echangeurs intermediaires disposes verticalement et entierement contenus dans la cuve reposent par leurs parties inferieures sur le support du coeur, a la peripherie de celui-ci. Ces echangeurs sont relies aux circuits de sodium secondaire par des canalisations traversant la dalle de fermeture de la cuve, et le grand bouchon tournant comporte une ouverture d'une dimension comparable aux dimensions de la section transversale des echangeurs intermediaires, placee a une distance de l'axe de rotation du bouchon tournant permettant d'amener cette ouverture a la verticale de chacun des echangeurs de chaleur successivement, par rotation du bouchon

1982-01-01

354

Condensation in horizontal heat exchanger tubes  

Energy Technology Data Exchange (ETDEWEB)

Many innovative reactor concepts for Generation III nuclear power plants use passive safety equipment for residual heat removal. These systems use two phase natural circulation. Heat transfer to the coolant results in a density difference providing the driving head for the required mass flow. By balancing the pressure drop the system finds its operational mode. Therefore the systems depend on a strong link between heat transfer and pressure drop determining the mass flow through the system. In order to be able to analyze these kind of systems with the help of state of the art computer codes the implemented numerical models for heat transfer, pressure drop or two phase flow structure must be able to predict the system performance in a wide parameter range. Goal of the program is to optimize the numerical models and therefore the performance of computer codes analyzing passive systems. Within the project the heat transfer capacity of a heat exchanger tube will be investigated. Therefore the tube will be equipped with detectors, both temperature and pressure, in several directions perpendicular to the tube axis to be able to resolve the angular heat transfer. In parallel the flow structure of a two phase flow inside and along the tube will be detected with the help of x-ray tomography. The water cooling outside of the tube will be realized by forced convection. It will be possible to combine the flow structure measurement with an angular resolved heat transfer for a wide parameter range. The test rig is set up at the TOPLFOW facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), so that it will be possible to vary the pressure between 5 and 70 bar. The steam mass content will be varied between 0 and 100 percent. The results will be compared to the large scaled Emergency Condenser Tests performed at the INKA test facility in Karlstein (Germany). The paper will explain the test setup and the status of the project will be presented. (authors)

Leyer, S.; Zacharias, T.; Maisberger, F.; Lamm, M. [AREVA NP GmbH, Paul-Gossen-Strasse 100, Erlangen, 91052 (Germany); Vallee, C.; Beyer, M.; Hampel, U. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstrasse 400, Dresden, 01328 (Germany)

2012-07-01

355

Heat exchange apparatus for a reactor  

Energy Technology Data Exchange (ETDEWEB)

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.

Gertsch, P.R.; McDaniels, J.D.; Thurston, G.C.

1980-09-30

356

Simultaneous synthesis of flexible heat exchanger network  

Energy Technology Data Exchange (ETDEWEB)

A framework is presented for generating flexible heat exchanger networks (HENs) over a specified range of variations in the flow rates and temperatures of the streams. The flexible HEN is synthesised using a combination of a multiperiod simultaneous MINLP model and search algorithms, where the total annual costs due to utility duties, exchanger areas and selection of matches are optimised. The simultaneous HEN synthesis allows the data to be distributed according to a probability distribution and it does not rely on the concept of pinch point. Both search algorithms involve a developed multiperiod NLP/LP model where utility costs are minimised. The proposed procedures are explained through an example including variations resulting in a network with variable splits and bypasses. This framework results in a HEN working under variations without losing stream temperature targets while keeping an economically optimal energy integration. (Author)

Aaltola, Juha [Helsinki Univ. of Technology,Hut (Finland)

2002-06-01

357

Characteristics of heat flow in recuperative heat exchangers  

Directory of Open Access Journals (Sweden)

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.

Lalovi? Milisav; Radovi? Žarko; Jaukovi? Nada

2005-01-01

358

PENGARUH TEBAL ISOLASI TERMAL TERHADAP EFEKTIVITAS PLATE HEAT EXCHANGER  

Directory of Open Access Journals (Sweden)

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.

Ekadewi Anggraini Handoyo

2000-01-01

359

DESIGN OF A COMPACT HEAT EXCHANGER FOR HEAT RECUPERATION FROM A HIGH TEMPERATURE ELECTROLYSIS SYSTEM  

Energy Technology Data Exchange (ETDEWEB)

Design details of a compact heat exchanger and supporting hardware for heat recuperation in a high-temperature electrolysis application are presented. The recuperative heat exchanger uses a vacuum-brazed plate-fin design and operates between 300 and 800°C. It includes corrugated inserts for enhancement of heat transfer coefficients and extended heat transfer surface area. Two recuperative heat exchangers are required per each four-stack electrolysis module. The heat exchangers are mated to a base manifold unit that distributes the inlet and outlet flows to and from the four electrolysis stacks. Results of heat exchanger design calculations and assembly details are also presented.

G. K. Housley; J.E. O' Brien; G.L. Hawkes

2008-11-01

360

Sealing strips in tubular heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

This paper presents design data relating to sealing strips for tubular heat exchangers. Sealing strip shapes, locations, and gap widths (the distance between the sealing strip and the nearest tube) are evaluated as to the pressure drop they create and, more importantly, as to their heat transfer characteristics. Velocity data were collected using a laser-Doppler anemometry system for which the fluid within the test model flow loop was refractive index matched with the pyrex rods that made up the tube bundle. A normalized heat transfer coefficient for each test has been inferred from the local velocity field. Unexpected trends were found in the heat transfer and pressure drop results of the gap width tests. It was concluded that the rectangular sealing strip located at the seventh row with a gap equal to the difference between the tube pitch and the tube diameter was the most effective. The successful application of LDA in the test program introduces a powerful measuring technique for the flow field in and around tube banks. From the measurements, pressure drops and heat transfer coefficients may be deduced. In addition, the technique will prove to be of great value in field of flow-induced vibrations where detailed velocity data are required.

Taylor, C.E.; Currie, I.G. (Univ. of Toronto, Ontario (Canada))

1987-08-01

 
 
 
 
361

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)

1976-01-01

362

The dynamic behaviour of heat exchangers  

International Nuclear Information System (INIS)

[en] 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)[fr] Les etudes de dynamique sur les centrales nucleaires exigent l'elaboration de modeles apparaissant sous forme d'equations differentlelles ordinaires. Ce rapport est consacre a la recherche de modeles d'echangeurs. Dans ces modeles les temperatures sont calculees exactement pour n'importe quel regime permanent. Pour tenir compte de la deformation des distributions de temperature en regime transitoire, on evalue les temperatures moyennes dans l'echangeur en s'appuyant, d'une part, sur les equations aux derivees partielles et, d'autre part, sur une analyse des phenomenes physiques. Les modeles contiennent au plus sept equations differentielles ordinaires. Ces modeles ont ete compares aux modeles mathematiques exacts et aussi a des resultats experimentaux, obtenus par l'EDF, sur les echangeurs d'EDF-1. Les resultats paraissent satisfaisants. (auteurs)

1963-01-01

363

Heat exchanger: from micro- to multi-scale design optimization  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a consideration of micro-heat exchangers design optimization for the aim of process intensification. Two examples are discussed to illustrate different ways of heat transfer intensification in micro-heat exchangers. To solve the key issue of the link between the micro-scale and the macro-scale, a multi-scale design optimization method using fractal and constructal approaches is introduced. The concept of a novel constructal heat exchanger is also proposed. (author)

Lingai Luo; Yilin Fan [Universite de Savoie (France). Laboratoire Optimisation de la Conception et Ingenierie de l' Environnement; Tondeur, D. [Laboratoire des Sciences du Genie Chimique du CNRS, Nancy (France)

2007-07-01

364

LMFBR intermediate-heat-exchanger experience  

Energy Technology Data Exchange (ETDEWEB)

This paper presents developmental and operating experience of large Intermediate Heat Exchangers (IHX's) in US from the Fast Flux Test Facility (FFTF) to the Clinch River Breeder Reactor Plant (CRBRP) to the Large Development Plant (LDP). Design commonalities and deviations among these IHX's are synopsized. Various developmental tests that were conducted in the areas of hydraulic, structural and mechanical design are also presented. The FFTF is currently operating. Performance data of the FFTF IHXs are reviewed, and comparisons between actual and predicted performances are made. The results are used to assess the adequacy of IHX designs.

Cho, S.M.; Beaver, T.R.

1983-01-01

365

Fluid dynamical considerations on heat exchanger networks  

Directory of Open Access Journals (Sweden)

Full Text Available The synthesis and analysis of heat exchanger networks are issues of great industrial interest due to the possibilities of decreasing plant costs, through the reduction of the utilities consumption and/or the number of equipments, in a grassroot design or retrofitting an existent network. The present paper explores a new design algorithm based on the Total Annual Cost (TAC) optimization for a thermal equipment, with mean tubeside and shellside flow velocities constraints, studying also the influence of pumping cost in the network’s final cost.

A. J. M. Vieira; F. L. P. Pessoa; E. M. Queiroz

2000-01-01

366

Fluid dynamical considerations on heat exchanger networks  

Directory of Open Access Journals (Sweden)

Full Text Available The synthesis and analysis of heat exchanger networks are issues of great industrial interest due to the possibilities of decreasing plant costs, through the reduction of the utilities consumption and/or the number of equipments, in a grassroot design or retrofitting an existent network. The present paper explores a new design algorithm based on the Total Annual Cost (TAC) optimization for a thermal equipment, with mean tubeside and shellside flow velocities constraints, studying also the influence of pumping cost in the network?s final cost.

Vieira A. J. M.; Pessoa F. L. P.; Queiroz E. M.

2000-01-01

367

Acoustic resonance in heat exchanger tube bundles  

Energy Technology Data Exchange (ETDEWEB)

A series of experiments has been made on aeroacoustic tones produced by flow over tubes in a duct. The sound is characterized by the onset of a loud and persistent acoustic resonance. The acoustic resonance occurs at the frequency of the acoustic modes. The magnitude and extent of the resonance are functions of tube pattern and tube pitch. The sound levels increase in proportion with Mach number, dynamic head and pressure drop. A design procedure for predicting the magnitude of the sound within the tube array is presented. Methods of resonance avoidance are illustrated. An example is made for a large petrochemical heat exchanger.

Blevins, R.D. (Rohr Industries, San Diego, CA (United States))

1994-02-01

368

Heat exchanger for a Stirling engine  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger is described for a Stirling engine comprising: a domed cylinder having a domed portion and a cylindrical portion. The domed cylinder serves as a high-temperature cylinder and a regenerator housing of the Stirling engine; a cylindrical inner liner which is coaxially disposed inside the domed cylinder and which divides the inside of the domed cylinder into an expansion space inside of the inner liner and a regenerator space between the outer surface of the inner liner and the inner surface of the cylindrical portion of the domed cylinder.

Fujiwara, M.; Nomaguchi, T.; Kazumoto, Y.; Tsuchino, K.; Kawajiri, K.; Hisamori, Y.

1987-05-05

369

Thermofluid characteristics of frosted finned-tube heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The performance of frosted finned-tube heat exchangers of different fin types is investigated by experiments in this paper. The effects of the air flow rate, the air relative humidity, the refrigerant temperature, and the fin type on the thermofluid characteristics of the heat exchangers are discussed. The time variations of the heat transfer rate, the overall heat transfer coefficient, and the pressure drop of the heat exchangers are presented. The heat transfer rate, the overall heat transfer coefficient, and the pressure drop for heat exchangers with re-direction louver fins are higher than those with flat plate fins and one-sided louver fins are. The amount of frost formation is the highest for heat exchangers with re-direction louver fins. (author)

Wei-Mon Yan; Hung-Yi Li [Huafan University, Taipei (Taiwan). Department of Mechatronical Engineering; Yeong-Ley Tsay [National Huwei Institute of Technology, Yunlin (Taiwan). Department of Aeronautical Engineering

2005-07-01

370

Microbial fouling control in heat exchangers  

International Nuclear Information System (INIS)

Biofilm formation in turbulent flow has been studied a great deal during the last 15 years. Such studies have provided the basis for further experiments designed to test the efficacy of industrial antimicrobials against biofilms in laboratory models and in actual real-world industrial water-treatment programs. Biofilm microbiology is relevant from the industrial perspective because adherent populations of microorganisms often cause an economic impact on industrial processes. For example, it is the adherent population of microorganisms in cooling-water systems that can eventually contribute to significant heat transfer and fluid frictional resistances. The microbiology of biofilms in heat exchangers can be related to the performance of industrial antimicrobials. The development of fouling biofilms and methods to quantitatively observe the effect of biofouling control agents are discussed in this paper.

1991-01-01

371

Fouling and corrosion of freshwater heat exchangers  

International Nuclear Information System (INIS)

Fouling in freshwater heat exchangers (HX) costs the Canadian nuclear power industry millions of dollars annually in replacement energy and capital equipment. The main reasons are loss of heat transfer and corrosion. Underdeposit pitting is the predominant corrosion mechanism. Erosion corrosion has also been observed. Failure analyses, field studies, and laboratory research have provided us with information to help explain the reasons for reduced performance. Newly installed HX tubing immediately becomes colonized with a complex community of bacteria in a slimey organic matrix. The biofilm itself produces corrosive species and in addition it promotes the attachment of sediment particles and the deposition of calcareous material. The result is a thick, adherent deposit which creates crevices, concentrates aggressive species and alters the system's hydrodynamics.

1992-01-01

372

High performance printed circuit heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

Three-dimensional thermal-hydraulic simulations have revealed a new flow channel configuration for Printed Circuit Heat Exchanger (PCHE) recuperators of a carbon dioxide gas turbine cycle. Simulation calculations were done changing the fin shape and angle parametrically to obtain an optimal flow channel configuration considering pressure drop and heat transfer performance. The new configuration has discontinuous fins with an S-shape, similar to a sine curve, in contrast to the conventional continuous zigzag configuration. The new configuration has one-fifth of the pressure drop reference to the conventional zigzag configuration with equal thermal-hydraulic performance. The pressure drop reduction is ascribed a superior uniform flow velocity profile in the flow area and elimination of reverse flows and eddies that occur around bend corners of zigzag flow channels in conventional PCHE. (author)

Tsuzuki, Nobuyoshi; Kato, Yasuyoshi; Ishiduka, Takao [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550 (Japan)

2007-07-15

373

Radiant heat exchange calculations in radiantly heated and cooled enclosures  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the development of a three-dimensional mathematical model to compute the radiant heat exchange between surfaces separated by a transparent and/or opaque medium. The model formulation accommodates arbitrary arrangements of the interior surfaces, as well as arbitrary placement of obstacles within the enclosure. The discrete ordinates radiation model is applied and has the capability to analyze the effect of irregular geometries and diverse surface temperatures and radiative properties. The model is verified by comparing calculated heat transfer rates to heat transfer rates determined from the exact radiosity method for four different enclosures. The four enclosures were selected to provide a wide range of verification. This three-dimensional model based on the discrete ordinates method can be applied to a building to assist the design engineer in sizing a radiant heating system. By coupling this model with a convective and conductive heat transfer model and a thermal comfort model, the comfort levels throughout the room can be easily and efficiently mapped for a given radiant heater location. In addition, objects such as airplanes, trucks, furniture, and partitions can be easily incorporated to determine their effect on the performance of the radiant heating system.

Chapman, K.S.; Zhang, P. [Kansas State Univ., Manhattan, KS (United States). Dept. of Mechanical Engineering

1995-08-01

374

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)

1995-01-01

375

Simulation Studies on A Cross Flow Plate Fin Heat Exchanger  

Directory of Open Access Journals (Sweden)

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.

M. Thirumarimurugan; T. Kannadasan; E. Ramasamy

2008-01-01

376

Diffusion-Welded Microchannel Heat Exchanger for Industrial Processes  

Energy Technology Data Exchange (ETDEWEB)

The goal of next generation reactors is to increase energy ef?ciency in the production of electricity and provide high-temperature heat for industrial processes. The ef?cient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process. The need for ef?ciency, compactness, and safety challenge the boundaries of existing heat exchanger technology. Various studies have been performed in attempts to update the secondary heat exchanger that is downstream of the primary heat exchanger, mostly because its performance is strongly tied to the ability to employ more ef?cient industrial processes. Modern compact heat exchangers can provide high compactness, a measure of the ratio of surface area-to-volume of a heat exchange. The microchannel heat exchanger studied here is a plate-type, robust heat exchanger that combines compactness, low pressure drop, high effectiveness, and the ability to operate with a very large pressure differential between hot and cold sides. The plates are etched and thereafter joined by diffusion welding, resulting in extremely strong all-metal heat exchanger cores. After bonding, any number of core blocks can be welded together to provide the required ?ow capacity. This study explores the microchannel heat exchanger and draws conclusions about diffusion welding/bonding for joining heat exchanger plates, with both experimental and computational modeling, along with existing challenges and gaps. Also, presented is a thermal design method for determining overall design speci?cations for a microchannel printed circuit heat exchanger for both supercritical (24 MPa) and subcritical (17 MPa) Rankine power cycles.

Piyush Sabharwall; Denis E. Clark; Michael V. Glazoff; Michael G. McKellar; Ronald E. Mizia

2013-03-01

377

Longitudinal conduction in crossflow heat exchanger with condensation  

International Nuclear Information System (INIS)

It is well recognized that longitudinal conduction through the wall causes a deterioration in the performance of heat exchangers. In the present study, this effect was investigated for a crossflow heat exchanger with condensation. The results indicated that under certain conditions the performance deterioration due to longitudinal conduction is significant but generally it is smaller compared to the case of heat transfer alone

1987-01-01

378

Vertical heat exchanger for high pressure fluidized bed coal combustors  

Energy Technology Data Exchange (ETDEWEB)

While the technology of pressurized fluidized bed combustion (PFBC) in a combined cycle for utility applications has advanced considerably there remain some technical problems to be resolved, two of which relate to the corrosion and erosion of the heat exchanger and gas turbine blades. Observations made by several researchers suggest that the geometry and orientation of heat exchangers significantly affect the tube erosion. Vertical heat exchanger configurations have been tested but not for sufficient duration to determine their reliability for withstanding erosion. For almost a decade New York University has supported the vertical heat exchanger concept for PFBC. Some limited experimental work has been reported to demonstrate its advantages. The paper reviews the experience gained by several researchers with in-bed heat exchangers, presents the advantages of vertical heat exchanger configuration for PFBC and, in addition, provides a design concept for the New York University PFBC facility. 12 references.

Zakkay, V.; Sellakumar, K.M.; Radhakrishnan, R.; McClung, J.D.

1986-12-01

379

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)

1995-01-01

380

Heat exchanger for fuel cell power plant reformer  

Energy Technology Data Exchange (ETDEWEB)

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.

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

 
 
 
 
381

Recent developments in finned tube heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

It is stated that major technological innovations have been achieved in the field of finned tube heat exchangers largely used as cooling or heating units, evaporators or condensers in a very wide range of applications within industry, automotive air conditioning and refrigeration. This is mainly due to competition between Japanese, European and American companies eager to increase the quality and performance of their products and to decrease costs of production and materials. Research and development programmes cover enhanced energy performance of thermodynamic processes, compact and lightweight equipment, improvement of reliability connected with mechanical performance and increased resistance to corrosion, vibration and high temperature. The aim of the publication is to present comprehensive reviews, in the form of articles, of the most important technological innovations that have been made recently in Europe, Japan and USA. The innovations concerning components and overall design related to air conditioning in buildings and the automotive industry are described. Experimental data and correlations regarding heat transfer and pressure drop behaviour found in recent literature is presented, and other special subjects are smooth and enhanced plate fins for operation in humid and dry air, condensation of refrigerants inside smooth and enhanced tubes and evaporation inside these tubes. The authors are employed at six European laboratories working under the Strategic Programme for Innovation and Technology Transfer (SPRINT) of the Commission of European Communities. (AB)

Marvillet, C. (ed.)

1994-01-01

382

Heat exchanger panel for solar energy with improved flow distribution  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger panel having a desired system of tubular passageways having a heat exchange medium wherein said panel includes opposed headers including island-like bonded portions and said passageways have entry and exit portions extending from said headers to provide ingress and egress openings for said heat exchange medium. The headers include as a part of the island-like bonded portions alphanumeric bonded portions to assist in properly installing the panel within a complete solar collector assembly. 10 drawings.

Kleine, C.A.; Middelton, V.L.

1984-04-24

383

Heat exchanger and water tank arrangement for passive cooling system  

Energy Technology Data Exchange (ETDEWEB)

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.

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

384

Heat exchanger support apparatus in a fluidized bed  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger is mounted in the upper portion of a fluidized combusting bed for the control of the temperature of the bed. A support, made up of tubes, is extended from the perforated plate of the fluidized bed up to the heat exchanger. The tubular support framework for the heat exchanger has liquid circulated there through to prevent deterioration of the support. 2 figs.

Lawton, C.W.

1982-05-25

385

A comparison of heat transfer enhancement in medium temperature thermal energy storage heat exchanger using fins and multitubes  

Energy Technology Data Exchange (ETDEWEB)

Experimental studies using a medium temperature phase change material (PCM) Erythritol, melting point 117.7 C, in a horizontal shell and tube system have been undertaken. The experimental programme investigated the suitability of Erythritol (a sugar based material) to deliver a near constant thermal energy to be used for the hot side of LiBr/water absorption cooling system. Four experimental configurations, consisting a base model with no heat enhancement (control system), systems enhanced with circular and longitudinal fins and a multitube system were studied. Experiments were conducted at the same inlet heat transfer fluid temperature of 140 C and mass flow rate of 30 kg min{sup 1} for the different configurations. The results presented include experimentally determined isotherm plots for the final melt illustrating the heat transfer characteristics of the systems and quantitative information relating to the transient change in temperature during the charging and discharging processes. The experimental results indicate that the multitube system achieved the best charging performance with the shortest melt time due to the presence of convection but showed large subcooling during the discharge process. The presence of longitudinal fins improved the conduction heat transfer significantly during the charging process due to increased heat transfer surface area and also reduced the level of subcooling during the discharge process. The circular finned system showed no significant improvement in melt time and size and as such would not be worthy of further development. (orig.)

Agyenim, Francis [Welsh School of Architecture, Cardiff Univ., Wales (United Kingdom); Eames, Philip [School of Engineering, Univ. of Warwick, Coventry (United Kingdom); Smyth, Mervyn [Centre for Sustainable Technologies, Univ. of Ulster, Newtownabbey (United Kingdom)

2008-07-01

386

Industrial applications for LIGA-fabricated micro heat exchangers  

Science.gov (United States)

One of the well-known benefits of micro scale is enhanced heat transfer. This fact provides the motivation for fabricating a variety of micro heat exchangers using derivatives of the LIGA micromachining process. These heat exchangers can be made of polymers, nickel (electroplated or electroless), or ceramics (Si3N4 and alumina are presently being investigated). These heat exchangers are envisioned for applications such as gas turbine blades, mechanical seals and/or bearings, boilers, condensers, radiators, evaporators, electronic component cooling, and catalytic converters. In this paper, methods to fabricate an array of heat exchangers for different applications are described. In addition, simple analytic models that illustrate the motivation for fabricating micro cross flow heat exchanges are shown to compare favorably with experimental heat transfer results.

Kelly, Kevin W.; Harris, Chad; Stephens, Lyndon S.; Marques, Christophe; Foley, Dan

2001-10-01

387

WASTE HEAT RECOVERY FROM BOILER OF LARGE-SCALE TEXTILE INDUSTRY  

Directory of Open Access Journals (Sweden)

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.

Prateep Pattanapunt; Kanokorn Hussaro; Tika Bunnakand; Sombat Teekasap

2013-01-01

388

Polymer spiral film gas-liquid heat exchanger for waste heat recovery in exhaust gases  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this master thesis report the development of an innovative spiral heat exchanger based on polymer materials is described. Building prototypes, erection of a test bench and firsts tests of the heat exchanger are presented. The heat exchanger prototype survived all tests especially several da...

Breton, Antoine

389

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.

2011-01-01

390

Global optimization algorithm for heat exchanger networks  

Energy Technology Data Exchange (ETDEWEB)

This paper deals with the global optimization of heat exchanger networks with fixed topology. It is shown that if linear area cost functions are assumed, as well as arithmetic mean driving force temperature differences in networks with isothermal mixing, the corresponding nonlinear programming (NLP) optimization problem involves linear constraints and a sum of linear fractional functions in the objective which are nonconvex. A rigorous algorithm is proposed that is based on a convex NLP underestimator that involves linear and nonlinear estimators for fractional and bilinear terms which provide a tight lower bound to the global optimum. This NLP problem is used within a spatial branch and bound method for which branching rules are given. Basic properties of the proposed method are presented, and its application is illustrated with several example problems. The results show that the proposed method only requires few nodes in the branch and bound search.

Quesada, I.; Grossmann, I.E. (Carnegie Mellon Univ., Pittsburgh, PA (United States))

1993-03-01

391

A practical method for defouling heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Since 1976, many projects have been initiated in Alberta by industry and by academic research institutions for better utilization of the province's energy resources. Funding for research and development efforts is supported in part by the Alberta/Canada Energy Resources Research Fund. Program priorities have focused on coal, energy preservation, renewable energy, as well as conventional energy resources. This publication deals with the results of freezing the progressive buildup of biofilm, or fouling, restoring the temperature of the heat exchanger and then flushing the liberated biofilm. Several cycles of freezing followed by fluid flow can be used. This phenomenon is referred to as ''Ice Nucleation''.

1987-01-01

392

Radiant heat exchange measurements for Tore Supra  

International Nuclear Information System (INIS)

[en] 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)

1984-01-01

393

A study on the heat transfer development of heat exchanger with vortex generator  

Energy Technology Data Exchange (ETDEWEB)

A numerical analysis using FLUENT code was carried out to investigate flow characteristics and heat transfer development of heat exchangers. The analysis results for both cases of the fin-circular tube and the fin-flat tube heat exchanger with the vortex generator show relatively higher heat transfer coefficient than that for both cases of the fin-circular tube and the fin-flat tube heat exchangers without the vortex generator. Also, the analysis result for the fin-circular tube heat exchanger with the vortex generator has relatively higher heat transfer coefficient and higher pressure loss than those for the fin-flat tube heat exchanger with the vortex generator. The results of this study can be used to design the heat exchanger with relatively low pressure loss and maximum heat transfer coefficient. 28 figs., 15 refs. (Author) .new.

Lee, Jung Sub; Oh, Kwang Suk; Kim, Sun Chul; Kim, Do Hyun; Oh, Jong Phil [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1996-05-01

394

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)

1998-01-01

395

Heat recovery from solids in a raining bed exchanger  

Energy Technology Data Exchange (ETDEWEB)

The concept of a raining bed exchanger is described. Used for heat recovery from gases or solid particles at high temperatures, experiments on a two-dimensional column are described and heat transfer data given. (author).

Boumehdi, L.; Guigon, P.; Large, J.F.

1985-01-01

396

Heat exchangers for temperature-sensitive, viscous liquids  

Energy Technology Data Exchange (ETDEWEB)

Static mixing elements have been successfully used recently to heat or cool viscous, temperature-sensitive liquids. The basic considerations which led to this development are indicated and the process engineering details of the mixer heat exchanger are discussed.

Heierle, A. (Sulzer Bros. Ltd., Winterthur (Switzerland))

1980-02-01

397

Entropy resistance analyses of a two-stream parallel flow heat exchanger with viscous heating  

Science.gov (United States)

Heat exchangers are widely used in industry, and analyses and optimizations of the performance of heat exchangers are important topics. In this paper, we define the concept of entropy resistance based on the entropy generation analyses of a one-dimensional heat transfer process. With this concept, a two-stream parallel flow heat exchanger with viscous heating is analyzed and discussed. It is found that the minimization of entropy resistance always leads to the maximum heat transfer rate for the discussed two-stream parallel flow heat exchanger, while the minimizations of entropy generation rate, entropy generation numbers, and revised entropy generation number do not always.

Cheng, Xue-Tao; Liang, Xin-Gang

2013-08-01

398

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

Science.gov (United States)

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.

Azad, E.

2012-07-01

399

Thermal and economic analysis of plastic heat exchangers for solar water heating  

Energy Technology Data Exchange (ETDEWEB)

The feasibility of polymer heat exchangers for solar water heaters is examined in terms of thermal performance and cost of tube-in-shell and immersed designs. High temperature nylon and cross-linked polyethylene were identified as suitable polymers for this application. These materials can meet the high temperature and pressure requirements of a domestic potable hot water system. The heat exchanger designs are compared for heat transfer area required to provide 3,000 and 6,000 W. A nylon tube-in-shell heat exchanger, sized for a 3,000 W load, is approximately 80% of the cost of a copper tube-in-shell heat exchanger. For an immersed heat exchanger, a high temperature nylon tube bank design has the lowest cost. The nylon tube bank heat exchanger, sized for a 3,000 W load, is approximately 80% the cost of an immersed coiled copper tube heat exchanger.

Liu, W.; Davidson, J.; Raman, R.; Mantell, S.

1999-07-01

400

Vertical drum heat exchanger for overheated steam production  

International Nuclear Information System (INIS)

[en] 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.)

1981-01-01

 
 
 
 
401

Comparison of heat exchanger modeling with data from CO2-to- CO2 printed circuit heat exchanger performance tests  

International Nuclear Information System (INIS)

A heat exchanger computational model has been developed at ANL for compact diffusion-bonded heat exchangers for the supercritical carbon dioxide (S-CO2) Brayton cycle. The ANL heat exchanger model calculates CO2 conditions at nodes along countercurrent hot and cold one-dimensional channels. The variation of thermophysical and transport properties of supercritical CO2 is accounted for through the use of detailed properties routines. Correlations for heat transfer and frictional pressure drop for zigzagged channels are based upon generalizations of fits to plots presented by Heatric for zigzagged channels. Performance testing was carried out for a 17.5 KW nominal heat duty Heatric PCHE having a core simulating the core of an individual LTR PCHE module. The tests were carried out in the ANL S-CO2 heat exchanger testing facility consisting of two CO2 loops up to 20 MP a and 180 deg.C. Nine separate test runs were conducted in which sixty-three sets of steady state operating conditions were established and heat exchange and pressure drop data were obtained. The heat exchanger model was compared versus the data for all sixty-three data sets. The ANL model for PCHEs is shown to agree very well with heat exchange data from the ANL heat exchanger performance tests, although the calculated pressure drops for the lower pressure higher temperature CO2 stream were typically larger than the measured pressure drops. (authors)

2010-01-01

402

Applying the temperature effectiveness method to heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Off-design variations in heat load, flow rates, and service water inlet (heat sink) temperature, such as those due to seasonal changes, have been observed to cause significant variation in temperature effectiveness. This paper examines the effect of off-design test conditions on temperature effectiveness and further presents a correction to the temperature effectiveness for off-design variation in service water inlet temperature. Temperature effectiveness is the ratio of the actual heat load to the maximum theoretical heat load. As heat exchanger thermal performance degrades, temperature effectiveness decreases. It has been discovered, however, that off-design variations in system heat load, system flows, and heat sink temperature cause false trends in the temperature effectiveness. Three heat exchange systems are used to study the temperature effectiveness method: a typical water-to-water heat exchanger, an air-to-water room cooler, and a main steam condenser.

Pesce, M.M. [Power Generation Technologies, Knoxville, TN (United States)

1994-12-31

403

On the thermoeconomical optimization of heat pipe heat exchanger HPHE for waste heat recovery  

International Nuclear Information System (INIS)

A thermoeconomic optimization analysis is presented yielding a simple algebraic formula for estimating the optimum HPHE effectiveness for energy recovery applications. The P1-P2 method is used in the present study, together with the ?-NTU method, for thermoeconomic analysis of a heat pipe heat exchanger, HPHE, of a noncondensing fluid type, i.e. employing water and air

2003-01-01

404

Conceptual design selection and development of a latent-heat thermal-energy-storage subsystem for a saturated-steam solar receiver and load  

Energy Technology Data Exchange (ETDEWEB)

The following latent heat storage concepts are described and evaluated in comparison with each other and with an oil/rock sensible heat storage system: (1) passive tube intensive (shell-and-tube