WorldWideScience
 
 
1

PENGARUH PENGGUNAAN BAFFLE PADA SHELL-AND-TUBE HEAT EXCHANGER  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 baffle...

Ekadewi Anggraini Handoyo

2001-01-01

2

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

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, the results of the experimental investigations of fluid flow and heat transfer in laboratory experimental shell-and-tube heat exchanger are presented. Shell-and-tube heat exchanger is with one pass of warm water on the shell side and two passes of cool water in tube bundle. Shell-and-tube heat exchanger is with 24x2 tubes (U-tube in triangle layout. During each experimental run, the pressure drops and the fluid temperatures on shell side, along the shell-and-tube heat exchanger (at positions defined in advance have been measured. Special attention was made to the investigation of the segmental baffles number influence of the shell-and-tube heat exchanger effectiveness.

Vuki? Mi?a V.

2014-01-01

3

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

Energy Technology Data Exchange (ETDEWEB)

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

Sencan Sahin, Arzu, E-mail: sencan@tef.sdu.edu.tr [Department of Mechanical Education, Technical Education Faculty, Sueleyman Demirel University, 32260 Isparta (Turkey); Kilic, Bayram, E-mail: bayramkilic@hotmail.com [Bucak Emin Guelmez Vocational School, Mehmet Akif Ersoy University, Bucak (Turkey); Kilic, Ulas, E-mail: ulaskilic@mehmetakif.edu.tr [Bucak Emin Guelmez Vocational School, Mehmet Akif Ersoy University, Bucak (Turkey)

2011-10-15

4

Performance of a shell-and-tube heat exchanger with spiral baffle plates  

International Nuclear Information System (INIS)

In a conventional shell-and-tube heat exchanger, fluid contacts with tubes flowing up and down in a shell, therefore there is a defect in the heat transfer with tubes due to the stagnation portions. Fins are attached to the tubes in order to increase heat transfer efficiency, but there exists a limit. Therefore, it is necessary to improve heat exchanger performance by changing the fluid flow in the shell. In this study, a highly efficient shell-and-tube heat exchanger with spiral baffle plates is simulated three-dimensionally using a commercial thermal-fluid analysis code, CFX4.2. In this type of heat exchanger, fluid contacts with tubes flowing rotationally in the shell. It could improve heat exchanger performance considerably because stagnation portions in the shell could be removed. It is proved that the shell-and-tube heat exchanger with spiral baffle plates is superior to the conventional heat exchanger in terms of heat transfer

2001-11-01

5

A SIMPLIFIED PREDICTIVE CONTROL FOR A SHELL AND TUBE HEAT EXCHANGER  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2010-01-01

6

Thermal Analysis of Shell and Tube Heat Ex-Changer Using C and Ansys  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a simplified model for the study of thermal analysis of shell-andtubes heat exchangers of water and oil type is roposed..Shell and Tube heat exchangers are having special importance in boilers, oil coolers, condensers, pre-heaters. They are also widely used in process applications as well as the refrigeration and air conditioning industry. The robustness and medium weighted shape of Shell and Tube heat exchangers make them well suited for high pressure operations. In this paper we have shown how to done the thermal analysis by using theoretical formulae for this we have chosen a practical problem of counter flow shell and tube heat exchanger of water and oil type, by using the data that come from theoretical formulae we have design a model of shell and tube heat exchanger using Pro-e and done the thermal analysis by using ANSYS software and comparing the result that obtained from ANSYS software and theoretical formulae. For simplification of theoretical calculations we have also done a C code which is useful for calculating the thermal analysis of a counter flow of water-oil type shell and tube heat exchanger.

v.Hari Haran,*, B g.Ravindra Reddy and C b.Sreehari

2013-07-01

7

A SIMPLIFIED PREDICTIVE CONTROL FOR A SHELL AND TUBE HEAT EXCHANGER  

Directory of Open Access Journals (Sweden)

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

S.RAJASEKARAN,

2010-12-01

8

Transient response of a shell and tube heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

Governing partial differential equations describing transient heat transfer for a one shell pass and two tube pass heat exchanger have been derived. These equations were solved using a finite difference method. The ultimate steady state temperatures agree well with the available closed form solution. The transient response of a heat exchanger can be used to predict its overall fouling resistance when steady state testing becomes impractical due to lack of sufficient heat load.

Chandra, V. [Public Service Electric and Gas Co., Hancocks Bridge, NJ (United States)

1994-12-31

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

2008-01-01

10

Review of shell-and-tube heat exchanger fouling and corrosion in geothermal power plant service  

Energy Technology Data Exchange (ETDEWEB)

Heat exchangers for hot geofluid/working substance vaporizers for binary power plants are considered. A brief description of the physical test apparatus and the geofluid chemistry for each of the several heat exchanger tests is presented. The fouling data developed from these tests are summarized, in most cases presenting a mathematical expression for the increase in fouling factor with time. The materials performance data developed from these same tests are explored. The performance of shell-and-tube heat exchangers used as condensers and ancillary coolers in the power plant heat rejection system is considered.

Ellis, P.F. II

1983-12-01

11

PARAMETER IDENTIFICATION AND CONTROL OF A SHELL AND TUBE HEAT EXCHANGER  

Directory of Open Access Journals (Sweden)

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

Arun Sivaram

2013-04-01

12

Analysis of field-performance data on shell-and-tube heat exchangers in geothermal service  

Energy Technology Data Exchange (ETDEWEB)

Analysis of field performance data from a binary cycle test loop using geothermal brine and a hydrocarbon working fluid is reported. Results include test loop operational problems, and shell-and-tube heat exchanger performance factors such as overall heat transfer coefficients, film coefficients, pinch points, and pressure drops. Performance factors are for six primary heaters having brine in the tubes and hydrocarbon in the shells in counterflow, and for a condenser having cooling water in the tubes and hydrocarbon in the shell. Working fluids reported are isobutane, 90/10 isobutane/isopentane, and 80/20 isobutane/isopentane. Performance factors are for heating each working fluid at supercritical conditions in the vicinity of their critical pressure and temperature and condensing the same fluid.

Silvester, L.F.; Doyle, P.T.

1982-03-01

13

3D NUMERICAL SIMULATIONS OF THE THERMAL PROCESSES IN THE SHELL AND TUBE HEAT EXCHANGER  

Directory of Open Access Journals (Sweden)

Full Text Available A shell and tube heat exchanger (STHE is one of the most often used apparatuses in chemical industry. One of the main goals of the STHE manufacturers is to improve their exploitation reliability and efficiency. Two approaches to the STHE design improvement are possible: experimental investigation, which is very expensive and time-consuming because of the shell side complex geometry, and numerical investigations. Numerical simulations can be used to check the old and to develop new and more efficient STHE designs. In this paper, the results of the numerical investigations of fluid flow and heat transfer in the laboratory experimental STHE are presented. Numerical simulation has been performed by using the PHOENICS code. The tube bundle has been modeled by using the concept of porous media. Standard k-e turbulence model is used.

Mi?a V. Vuki?

2014-01-01

14

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

15

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

International Nuclear Information System (INIS)

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

2010-03-01

16

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

Energy Technology Data Exchange (ETDEWEB)

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

Elsays, Mostafa A. [College of Technology, Taif (Saudi Arabia). Computer Technology Dept.; Naguib Aly, M; Badawi, Alya A. [Alexandria Univ. (Egypt). Nuclear Engineering Dept.

2010-03-15

17

Vibration analysis of shell-and-tube heat exchangers: an overview-Part 2: vibration response, fretting-wear, guidelines  

Science.gov (United States)

Design guidelines were developed to prevent tube failures due to excessive flow-induced vibration in shell-and-tube heat exchangers. An overview of vibration analysis procedures and recommended design guidelines is presented in this paper. This paper pertains to liquid, gas and two-phase heat exchangers such as nuclear steam generators, reboilers, coolers, service water heat exchangers, condensers, and moisture-separator-reheaters. Part 2 of this paper covers forced vibration excitation mechanisms, vibration response prediction, resulting damage assessment, and acceptance criteria.

Pettigrew, M. J.; Taylor, C. E.

2003-11-01

18

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 performanc...

Raj Karuppa Thundil R.; Ganne Srikanth

2012-01-01

19

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

International Nuclear Information System (INIS)

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

2013-12-01

20

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

Directory of Open Access Journals (Sweden)

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

Avinash D Jadhav

2014-07-01

 
 
 
 
21

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

International Nuclear Information System (INIS)

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

1987-01-01

22

Thermal-economic multi-objective optimization of shell and tube heat exchanger using particle swarm optimization (PSO)  

Science.gov (United States)

Many studies are performed by researchers about shell and tube heat exchanger (STHE) but the multi-objective particle swarm optimization (PSO) technique has never been used in such studies. This paper presents application of thermal-economic multi-objective optimization of STHE using PSO. For optimal design of a STHE, it was first thermally modeled using e-number of transfer units method while Bell-Delaware procedure was applied to estimate its shell side heat transfer coefficient and pressure drop. Multi objective PSO (MOPSO) method was applied to obtain the maximum effectiveness (heat recovery) and the minimum total cost as two objective functions. The results of optimal designs were a set of multiple optimum solutions, called `Pareto optimal solutions'. In order to show the accuracy of the algorithm, a comparison is made with the non-dominated sorting genetic algorithm (NSGA-II) and MOPSO which are developed for the same problem.

Ghanei, A.; Assareh, E.; Biglari, M.; Ghanbarzadeh, A.; Noghrehabadi, A. R.

2014-04-01

23

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 SciELO Brazil | Language: English 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 = 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.

24

Avoiding vibration-induced tube failures in shell and tube heat exchangers  

International Nuclear Information System (INIS)

The past few years has seen a very significant increase of activity in heat exchangers tube vibration research, both analytical and experimental. Some of the results of this work are examined and discussed in the context of how best they may be applied in the assessment of heat exchangers at the design stage. Special attention is focussed on the overall picture and on the simplifications which can be made in many instances. (author)

1979-01-01

25

Thermodynamic analysis of latent heat storage in a shell-and-tube heat exchanger  

International Nuclear Information System (INIS)

This paper addresses the entropy generation aspects of a latent heat storage in which the energy delivered by a hot gas flowing through a cylindrical tube induces melting of the material surrounding the tube. The heat transfer for conduction-dominated melting is analyzed, taking into account the two-dimensional effects. The storage process irreversibilities associated with both the gas flow and the heat transfer (including entropy generation in the melted layer) are considered. The number of entropy generation units, which is a measure of the thermodynamic imperfection of the energy storage process, is expressed as a function of the main design parameters of the system. Analytic bounds and simplified asymptotic expressions for this quantity are derived. The results are compared with earlier one-dimensional studies

1992-05-01

26

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

27

Design and Simulation of Conventional and Intelligent Controllers for Temperature Control Of Shell and Tube Heat Exchanger System  

Directory of Open Access Journals (Sweden)

Full Text Available Heat exchanger system is widely used in chemical plants because it can sustain wide range of temperature and pressure. The main purpose of a heat exchanger system is to transfer heat from a hot fluid to a cooler fluid, so temperature control of outlet fluid is of prime importance. The designed controllers will regulate the temperature of the outgoing fluid to a desired set point in the shortest possible time irrespective of load and process disturbances, equipment saturation and nonlinearity. To control the temperature of outlet fluid of the heat exchanger system, a conventional P,PI and PID controller can be used. Due to nonlinear nature, shell and tube heat exchanger system is hard to model and control using conventional methods. The intelligent controllers are effective for nonlinear processes. In this paper, conventional P,PI,PID and IMC based PID controllers are designed and simulation results are presented and discussed. From the results it is observed that IMC based PID controller gives better results when compared to other controllers. To improve the performance the fuzzy controller and model based neuro controllers (inverse and internal model controllers are designed and simulated. To develop model based neuro controllers forward and inverse neuro model are developed, trained and validated. Simulation studies are carried out with fuzzy logic controller and model based neuro controllers for servo and regulatory problems. The results are presented and discussed. It is observed that ,fuzzy logic controller and IMC based PID controllers are giving better results when compared to conventional PID controller and model based neuro controllers.

E.saranya

2013-07-01

28

Design Optimization of Shell and Tube Heat Exchanger by Vibration Analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

29

Design Optimization of Shell and Tube Heat Exchanger by Vibration Analysis  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper a simplified approach to optimize the design of Shell Tube Heat Exchanger [STHE] by flow induced vibration analysis [FVA] is presented. The vibration analysis of STHE helps in achieving optimization in design by prevention of tube failure caused due to flow induced vibration. The main reason for tube failure due to flow induced vibration is increased size of STHE. It is found that in case of increased size of STHE, the surface area and number of tubes increases, thus the understanding and analysis of vibration becomes a very difficult task. Again it is found that flow induced vibration analysis is considered as an integral part of mechanical & thermal design of STHE. The detailed design, fabrication, testing and analysis work was carried out at Alfa Laval (India, Ltd., Pune-10.

S. H. Gawande

2011-08-01

30

Expansion of a radial jet from a guillotine tube breach in a shell-and-tube heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

Aerodynamics of a particle-laden gas jet entering the secondary side of a shell-and-tube heat exchanger from a tube guillotine breach, determines to a large extent radioactive retention in the break stage of the steam generator (SG) during hypothetical SGTR accident sequences in pressurized nuclear water reactors (PWRs). These scenarios were shown to be risk-dominant in PWRs. The major insights gained from a set of experiments into such aerodynamics are summarized in this paper. A scaled-down mock-up with representative dimensions of a real SG was built. Two-dimensional (2D) PIV technique was used to characterize the flow field in the space between the breach and the neighbor tubes in the gas flow range investigated (Re{sub D} = 0.8-2.7 x 10{sup 5}). Pitot tube measurements and CFD simulations were used to discuss and complement PIV data. The results, reported mainly in terms of velocity and turbulent intensity profiles, show that jet penetration and gas entrainment are considerably enhanced when increasing Re{sub D}. The presence of tubes was observed to distort the jet shape and to foster gas entrainment with respect to a jet expansion free of tubes. Turbulence intensity level close to the breach increases linearly with Re{sub D}. Account of this information into aerosol modeling will enhance predictive capability of inertial impaction and turbulent deposition equations. (author)

Velasco, F.J.S.; del Pra, C. Lopez; Herranz, Luis E. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Nuclear fission division, Nuclear Safety Research Unit, Avda. Complutense, 22, P.O. Box 28040 Madrid (Spain)

2008-02-15

31

Analysis of field-performance data on shell-and-tube heat exchangers in geothermal serivce  

Energy Technology Data Exchange (ETDEWEB)

Problems encountered in supercritical heat transfer calculations are discussed. Data evaluation models and results for primary heaters and condenser are presented. Results cover predicated areas, overall heat transfer coefficients, shell side film coefficients, mean temperature differences, pinch points, shell side pressure drops, and condensing coefficients. Test results are for isobutane and mixtures of isobutane/isopentane.

Doyle, P.T.; Silvester, L.F.

1982-09-01

32

Analysis of local shellside heat and mass transfer in the shell-and-tube heat exchanger with disc-and-doughnut baffles  

Energy Technology Data Exchange (ETDEWEB)

A mass transfer measuring technique is used to visualize and determine the shellside local heat transfer coefficients at each tube in two representative baffle compartments of a shell-and-tube heat exchanger with disc-and-doughnut baffles. The fluid flow adjacent to the tube is analysed and the heat transfer in the zones of separated flow discussed. The shellside flow distribution is determined through the measurements of the local pressure drop in the baffle-tube and baffle-shell clearances. Compared to the single-segmental baffle, the disc-and-doughnut baffles have a higher effectiveness of heat transfer to pressure drop. This investigation presents also per-tube and per-compartment averaged heat transfer coefficients. (author)

Li, H. [Jiang-OAI Joint Institute, Nanchang (China); Kottke, V. [Hohenheim University, Stuttgart (Germany). Institute of Food Technology

1999-07-01

33

Simulation of (EG+Al2O3 Nanofluid Through the Shell and Tube Heat Exchanger with Rectangular Arrangement of Tubes and Constant Heat Flux  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, the characteristics of (EG+AL2O3 nanofluid and (EG fluid which cross a rectangular arrangement of tubes in a shell and tubes heat exchanger have been investigated. The stagnation point, separation point, heat transfer coefficient and shear stress in both of nanofluid and purefluid have been determined and compared with each other. The heat transfer and velocity simulation of two phase flow have been done by mixture model. Results show that by using of nanofluid, the stagnation and separation points of flow were postponed and the amount of heat transfer coefficient and shear stress increased but the effect of shear stress increase can be neglected in compare of unusual heat transfer rising.

F. Khoddamrezaee

2010-01-01

34

Supercritical heat-exchange field test: field-performance data on shell-and-tube heat exchangers in geothermal service  

Energy Technology Data Exchange (ETDEWEB)

Presented are results from a binary-cycle test loop. Results cover loop operational problems, overall heat transfer coefficients, LMTD's, and duties for six primary heaters in counterflow having brine in the tubes and hydrocarbon in the shells, and for a condenser. Fluids tested were isobutane and mixtures of isobutane/isopentane; each heated at supercritical conditions and condensed at subcritical conditions.

Silvester, L.F.; Doyle, P.T.

1982-09-01

35

Shell-side single-phase flows and heat transfer in shell-and-tube heat exchangers, 3  

International Nuclear Information System (INIS)

An experimental investigation is performed to find the axial and circumferential distribution of local heat transfer coefficients around a tube bundle in segmentally turbular heat exchangers. The variation in the axial distribution of the heat transfer coefficient is found to be negligible compared with that of circumferential distribution or that within the tube bundle. Local heat transfer coefficients are sensitive to the ratio of the inlet nozzle diameter to the shell diameter in the inlet nozzle region of the tube bundle, while they remain invariant in the center region. No remarkable decrease of local heat transfer coefficients in the window zone is observed, so it is considered that there isn't any effective recirculation zones at the edge there. The normalization of the circumferential heat transfer coefficient using its averaged value keeps the distribution pattern unchanged with the Reynolds number, the ratio of inlet nozzle diameter to shell diameter and location of the tube within the bundle. These normalized values are assumed to agree with those of a tube bank of two dimensional array, with reasonable accuracy. (author)

1987-01-01

36

On-line model-based performance monitoring of a shell-and-tube type heat exchanger using steam and water  

International Nuclear Information System (INIS)

The on-line performance monitoring of a shell-and-tube type heat exchanger using steam and water, which is one of the key components of distributed energy supply systems, has been developed on the basis of a theoretical model. In this on-line performance monitoring, output process variables and performance of the heat exchanger in response to the variation in measured input process variables are first estimated by using its steady-state model. These estimated values are then compared with the measured ones. Its effectiveness has been confirmed by the demonstration experiments conducted not only in the steady and transient states but also under the condition of air accumulation in the shell as one of the common failures of this type of heat exchanger. The results confirm the sufficient accuracy of estimating the output process variables and heat exchange performance in a wide operating range, and the capability of detecting the deterioration of the heat exchange performance due to the air accumulation in a short period

2008-10-01

37

Design and Simulation of Conventional and Intelligent Controllers for Temperature Control Of Shell and Tube Heat Exchanger System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Heat exchanger system is widely used in chemical plants because it can sustain wide range of temperature and pressure. The main purpose of a heat exchanger system is to transfer heat from a hot fluid to a cooler fluid, so temperature control of outlet fluid is of prime importance. The designed controllers will regulate the temperature of the outgoing fluid to a desired set point in the shortest possible time irrespective of load and process disturbances, equipment saturation and nonlinearity....

2013-01-01

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

Perancangan Heat Exchanger Type Shell And Tube Untuk After Cooler Kompressor Dengan Kapasitas 8000 m3/hr Pada Tekanan 26,5 Bar  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dalam kehidupan sehari-hari banyak terlihat fenomena perpindahan panas dari material atau fluida yang mempunyai temperatur lebih tinggi ke material atau fluida yang mempunyai temperatur lebih rendah. Dalam dunia industri fenomena perpindahan panas tersebut dimanfaatkan untuk keperluan proses dengan menggunakan suatu alat yang biasa disebut sebagai penukar panas atau heat exchanger. Heat exchanger merupakan alat yang digunakan sebagai media untuk memindahkan panas dari fluida yang bertemperatu...

2011-01-01

40

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

2013-04-01

 
 
 
 
41

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 repla...

2013-01-01

42

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

43

Heat exchanger module test  

Energy Technology Data Exchange (ETDEWEB)

The heat exchanger module test is a cooperative field test of shell-and-tube heat exchangers to be performed with brine from Chevron Resources Company's Heber, California, field. Overall heat transfer coefficients will be measured with isobutane and a mixture of isobutane-isopentane as the working fluid in a simulated power cycle.

Fulton, R.L.

1978-06-01

44

Advantages of brazed heat exchangers in the gas processing industry  

Energy Technology Data Exchange (ETDEWEB)

Brazed aluminum heat exchangers have superior heat transfer capabilities and can be cost effective for non-corrosive gases and liquids as compared with traditional shell-and-tube exchangers. Even so, brazed aluminum exchangers are often not considered because of complicated design equations and complex stacking arrangements. The simpler yet less efficient shell-and-tube exchangers or networks of shell-and-tubes are employed instead. Recently, the design equations for multistream brazed aluminum heat exchangers for both single and multiphase flow have been added to the Heat Exchanger Rating package of the process simulator PROSIM{reg_sign}.

Lunsford, K.M. [Bryan Research and Engineering, Bryan, TX (United States)

1996-12-31

45

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

46

COMPARATIVEANALYSIS OF ADVANCED CONTROLLERS IN A HEAT EXCHANGER  

Directory of Open Access Journals (Sweden)

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

Mr. P.Sivakumar

2013-01-01

47

Analysis of the influence of operating conditions and geometric parameters on heat transfer in water-paraffin shell-and-tube latent thermal energy storage unit  

Energy Technology Data Exchange (ETDEWEB)

A transient heat transfer phenomenon during charging and discharging of the shell-and-tube latent thermal energy storage system has been analysed in this paper. The mathematical model, regarding the conjugate problem of transient forced convection and solid-liquid phase change heat transfer based on the enthalpy formulation, has been presented. A fully implicit two-dimensional control volume FORTRAN computer code has been developed for solving governing equations with initial and boundary conditions. The numerical model is validated with experimental data obtained by experimental investigations that have been performed on the test unit with technical grade paraffin as the phase change material (PCM) and water as the heat transfer fluid (HTF). Numerical predictions match the experimental results. This pointed out that the presented numerical procedure could be accurately used for transient heat transfer simulation. A series of numerical calculations have been done in order to analyse the influence of several HTF operating conditions and several geometric parameters on the heat transfer process inside the water-paraffin shell-and-tube latent thermal energy storage (LTES) unit. Numerical results, which could be used for operating conditions and geometry optimization, provide guidelines for the design of the latent thermal energy storage system. (author)

Trp, Anica; Lenic, Kristian; Frankovic, Bernard [Faculty of Engineering, University of Rijeka, Vukovarska 58, HR-51000 Rijeka (Croatia)

2006-11-15

48

CFD investigation of maldistribution effects on crude-oil fouling in shell and tube exchangers[Computerized Fluid Dynamics  

Energy Technology Data Exchange (ETDEWEB)

Maldistribution is known to reduce the effectiveness of heat exchangers. When hot, low velocity regions are created behind baffles or at the periphery of a tube bundle there can be a significant increase in fouling rate that further reduces performance. By using local, scalar, radial and axial models for heat transfer and pressure drop we can build 3-dimensional CFD models of the shell-side to get a good estimation of exchanger performance. By using the well known and simple fouling model of Ebert and Panchal (1992), we explore the effect of velocity and temperature on shell-side crude-oil fouling. This provides a convenient way of assessing improved geometries for fouling duties, or for customising fouling models based on plant operating data. (au)

Clarke, R.H.; Nicolas, F. [Cal Gavin Ltd., Alcester (United Kingdom)

2000-08-01

49

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

50

Shell & Tube Type Heat Exchangers: An Overview  

Directory of Open Access Journals (Sweden)

Full Text Available This paper is concerned with the study of shell & tube type heat exchangers along with its applications and also refers to several scholars who have given the contribution in this regard. Moreover the constructional details, design methods and the reasons for the wide acceptance of shell and tube type heat exchangers has been described in details inside the paper.

Vindhya Vasiny Prasad Dubey

2014-06-01

51

An experimental and numerical investigation of heat transfer during technical grade paraffin melting and solidification in a shell-and-tube latent thermal energy storage unit  

Energy Technology Data Exchange (ETDEWEB)

The latent thermal energy storage system of the shell-and-tube type during charging and discharging has been analysed in this paper. An experimental and numerical investigation of transient forced convective heat transfer between the heat transfer fluid (HTF) with moderate Prandtl numbers and the tube wall, heat conduction through the wall and solid-liquid phase change of the phase change material (PCM), based on the enthalpy formulation, has been presented. A fully implicit two-dimensional control volume Fortran computer code, with algorithm for non-isothermal phase transition, has been developed for the solution of the corresponding mathematical model. The comparison between numerical predictions and experimental data shows good agreement for both paraffin non-isothermal melting and isothermal solidification. In order to provide guidelines for system performance and design optimisation, unsteady temperature distributions of the HTF, tube wall and the PCM have been obtained by a series of numerical calculations for various HTF working conditions and various geometric parameters, and the thermal behaviour of the latent thermal energy storage unit during charging and discharging has been simulated. (author)

Trp, Anica [Faculty of Engineering, University of Rijeka, Vukovarska, 58, HR-51000 Rijeka (Croatia)

2005-12-01

52

Vibration isolation of dimple plate heat exchangers / Pieter Vergeer  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dimple plate heat exchangers are a new type of welded compact plate heat exchangers. The dimple plates increase the turbulence of the fluid flowing over the plate, increasing the efficiency of the heat exchanger without increasing pressure drop over the heat exchanger. The compact design of the heat exchanger makes it possible to install the heat exchanger at the top of condenser columns, reducing the footprint area of the column by replacing standard shell and tube condense...

Vergeer, Pieter

2012-01-01

53

Optimisation of intermediate heat exchanger for PFBR  

International Nuclear Information System (INIS)

In the Prototype Fast Breeder Reactor (PFBR) intermediate heat exchangers (IHX) enable the transfer of thermal power from the active primary sodium to inactive secondary sodium which in turn transfers the heat to produce steam. The IHX is a vertical shell and tube heat exchanger with primary sodium on the shell side and secondary sodium on the tube side. For sizing the IHX parametric studies have been carried out and the results are given

1995-01-01

54

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

International Nuclear Information System (INIS)

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

2010-11-01

55

Heat exchanger with leak detecting double wall tubes  

Energy Technology Data Exchange (ETDEWEB)

A straight shell and tube heat exchanger utilizing double wall tubes and three tubesheets to ensure separation of the primary and secondary fluid and reliable leak detection of a leak in either the primary or the secondary fluids to further ensure that there is no mixing of the two fluids.

Bieberbach, George (Tampa, FL); Bongaards, Donald J. (Seminole, FL); Lohmeier, Alfred (Tampa, FL); Duke, James M. (St. Petersburg, all of, FL)

1981-01-01

56

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

57

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

58

Experimental results of the 85 MWTH SNR-300 intermediate heat exchanger  

International Nuclear Information System (INIS)

This paper presents some experimental results obtained from the steady and unsteady state experiments carried out in the full scale prototype 85 MWth SNR-300 intermediate heat exchanger. This heat exchanger is a sodium to sodium heat exchanger of the shell-and-tube type. The experimental results presented in this paper were used for the validation of the multi-dimensional thermal hydraulic calculations with the computercodes COMMIX and PHOENICS

1985-01-01

59

Improvement of high temperature heat exchanger efficiency by inserted porous metal plates  

International Nuclear Information System (INIS)

Augmentation of high temperature shell-and-tube heat exchanger efficiency by insertions of porous plates is experimentally investigated. The results show its advantageous feature that the Nusselt number increases by 40 to 65 percent and that the shell temperature could be purposely cooled to meet the requirements from structural designing. 5 refs

1980-01-01

60

Heat exchangers  

International Nuclear Information System (INIS)

The aim of this invention is to provide improvements in the circulation of the fluids in shell type heat exchangers used in the generation of steam, especially those operating by indirect heat exchange with a fluid circulating through a nuclear reactor. It is claimed that the improvements described promote the natural circulation both in the radial and axial directions and also reduce or eliminate sludge buildup within the exchanger. Thus the possibility of tube failure in a heat exchanger is reduced and the operation and maintenance of a heat exchanger are improved such that its useful life is enhanced and its efficiency increased. (U.K.)

1976-01-01

 
 
 
 
61

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

International Nuclear Information System (INIS)

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

2012-01-01

62

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

63

Flat plate heat exchangers for the new production reactor  

Energy Technology Data Exchange (ETDEWEB)

The New Production Reactor (NPR) will require heat exchangers (HX) as part of the ancillary equipment. The most common type of heat exchanger in the US is the shell and tube, the type presently in SRP reactor service. This type of design is the one that is normally described in detail in heat transfer texts. Other designs are more efficient, and there was a period when these designs were actively modified. The largest driving force for higher efficiency HX was the OPEC produced energy shortage of the early 1970's. Several comments were made by B.S. Spangler about flat plate HX for the NPR after my initial comparison between shell and tube and flat plate HX (DPST-88-729). Since answers were not readily available, Philippe Marchal of Packinox (Louveciennes, France) agreed to visit SRL. This report contains a series of answers to all comments raised in DPST-88-743 and some general statements comparing flat plate HX to shell and tube HX. 1 fig., 2 tabs.

Ondrejcin, R.S.

1988-12-07

64

Efficient NPO TsKTI shell-and-tube heaters for industrial and municipal power engineering  

Science.gov (United States)

New shell-and-tube heaters for heat supply systems, industrial power installations, and cogeneration stations are considered. They feature better reliability and thermal efficiency and have certain operational advantages as compared with serially produced apparatuses. The new heaters are recommended for being widely used in municipal and industrial power engineering installations.

Permyakov, V. A.; Permyakov, K. V.; Kuznetsov, A. N.; Divova, G. V.

2008-12-01

65

Heat exchanger  

International Nuclear Information System (INIS)

In the main patent, a description was given of a heat exchanger with an exchange surface in preformed sheet metal designed for the high pressure and temperature service particularly encountered in nuclear pressurized water reactors and which is characterised by the fact that it is composed of at least one exchanger bundle sealed in a containment, the said bundle or bundles being composed of numerous juxtaposed individual compartments whose exchange faces are built of preformed sheet metal. The present addendun certificate concerns shapes of bundles and their positioning methods in the exchanger containment enabling its compactness to be increased

1975-03-10

66

Heat exchanger design: why guess a design fouling factor when it can be optimized  

Energy Technology Data Exchange (ETDEWEB)

A new general surface heat exchanger design relationship is derived that uniquely relates the optimum design fouling resistance and the optimum design heat transfer coefficient with the ratio of cleaning cost to capital plus operating costs, at the optimum design condition. Implementation of this simple result to practical problems in design, however, requires numerical techniques. A new shell and tube heat exchanger design program, SIZEHX, is applied to a problem of current interest to confirm the derivation. SIZEHX can cost effectively perform single-step, multiparameter cost optimizations on single phase or supercritical exchanger arrays with variable fluid properties and arbitrary linear fouling for single-pass, segmentally baffled shell-and-tube configurations for a variety of fluid pairs, including hydrocarbon mixtures. The economic influence of several general design parameters on a geothermal exchanger are presented in the form of 3-D computer generated plots.

Pope, W.L.; Pines, H.S.; Fulton, R.L.; Doyle, P.A.

1978-06-01

67

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

1983-09-06

68

Heat exchanger  

International Nuclear Information System (INIS)

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

1977-01-01

69

Thermal design of multi-fluid mixed-mixed cross-flow heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

A fast analytical calculation method is developed for the thermal design and rating of multi-fluid mixed-mixed cross-flow heat exchangers. Temperature dependent heat capacities and heat transfer coefficients can iteratively be taken into account. They are determined at one or two special reference temperatures. Examples are given for the application of the method to the rating of special multi-fluid multi-pass shell-and-tube heat exchangers and multi-fluid cross-flow plate-fin heat exchangers. The accuracy of the method is tested against numerical calculations with good results. (orig.)

Roetzel, W. [Helmut Schmidt University, Institute of Thermodynamics, Hamburg (Germany); Luo, X. [Helmut Schmidt University, Institute of Thermodynamics, Hamburg (Germany); University of Shanghai for Science and Technology, Institute of Thermal Engineering, Shanghai (China)

2010-11-15

70

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

71

Heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger assembly is described for cooling the interior of a closed cabinet containing electronic components or the like, comprising: a finned heat pipe core including: a plurality of spaced heat pipes positioned in at least one row, a plurality of spaced fins which are provided with colinear apertures through which each of the plurality of heat pipes can extend, the heat pipes being secured to the fins; affixing means for securing the finned heat pipe core to an associated cabinet; and, a pair of fans, one being operatively connected with each end of the finned heat pipe core, one of the fans, and an associated first end of the heat pipe core, being in contact with only the air inside the associated closed cabinet, the other of the fans and an associated second end of the finned heat pipe core being in contact with only the ambient air outside the associated cabinet, and wherein the fins have a spacing and a thickness which is sized to fit the performance curve of the fans wherein the fans each have a capacity of approximately 100 CFM (cubic feet per minute) and wherein the finned heat pipe core is optimized for the fans such that approximately fourteen fins are provided per inch of heat pipe length with each of the fins being approximately 0.008 inches in thickness, whereby the finned heat pipe core and the pair of fans are capable of transferring at least 200 watts of heat when the temperature inside the associated cabinet is approximately 20/sup 0/C above the ambient temperature.

Noren, D.W.

1986-07-15

72

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

73

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

Energy Technology Data Exchange (ETDEWEB)

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

Beaver, R. J.

1978-12-01

74

Heat exchangers  

International Nuclear Information System (INIS)

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

1976-01-01

75

Life Cycle Cost Model for Condition Monitoring of heat exchanger  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Shell and tube heat exchangers (H/X) are widely used in the industry. Offshore, the H/Xs are used as heaters or coolers. In this thesis it is assumed that the H/X function is to cool down gas or oil. A large number of different configuration of H/X exist today, single pass and u-bend is most used offshore. This thesis looks further into the most used H/X on an offshore platform single pass.

The thesis is dealing with formulas that indicate performance of an H/X. It is normal...

Melingen, Daniel

2010-01-01

76

Life Cycle Cost Model for Condition Monitoring of heat exchanger  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Shell and tube heat exchangers (H/X) are widely used in the industry. Offshore, the H/Xs are used as heaters or coolers. In this thesis it is assumed that the H/X function is to cool down gas or oil. A large number of different configuration of H/X exist today, single pass and u-bend is most used offshore. This thesis looks further into the most used H/X on an offshore platform single pass. The thesis is dealing with formulas that indicate performance of an H/X. It is normal to have the abili...

Melingen, Daniel

2010-01-01

77

Heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger is described which consists of: spaced generally parallel header and tank constructions; each of the header and tank constructions having elongated, spaced, tube receiving holes in a header surface thereof; the holes in one header surface being aligned with and facing corresponding holes in the other header surface; and elongated open ended, flattened tubes extending between and into the header and tank constructions through aligned ones of the holes; the portions of each header surface between the holes including exteriorly convex domes defined by compound curves to thereby provide increased resistance to deformation as a result of force exerted by a pressurized fluid within the header and tank construction.

Saperstein, Z.P.; Awe, R.C.; Costello, N.F.; Larrabee, S.R.

1986-10-07

78

Corrosive Resistant Heat Exchanger.  

Science.gov (United States)

A corrosive and erosive 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 cont...

S. L. Richlen

1987-01-01

79

Segmented heat exchanger  

Science.gov (United States)

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

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

2010-12-14

80

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

1996-02-01

 
 
 
 
81

Numerical predictions of shell-side fluid flow and heat transfer in heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

A computer algorithm was developed to simulate two- and three-dimensional fluid flow and heat transfer in the shell side of single and two phase shell and tube heat exchangers. The governing equations are solved in primitive variable form using a semi-implicit consistent formulation in which a segregated pressure correction linked algorithm is employed. Numerical predictions are obtained for isothermal, two-dimensional, axisymmetric turbulent flow in a single phase experimental disc-and-doughnut heat exchanger. The system consists of alternating and equispaced doughnut and disc baffles located in a pipe with water flowing in turbulent regions. The two equation turbulence model as proposed by Nagano and Hishida (1987) is modified to accomodate disc and doughnut baffles. The proposed model leads to considerable computer time savings and better predictive capability for fluid flow in multibaffled regions. Four different types of two-phase shell and tube heat exchangers and steam condensors were modelled, and the numerical predictions were critically assessed by comparison with data for an experimental condensor and power plant condensor, indicating good agreeement. 44 refs., 56 figs., 9 tabs.

Zhang, Chao.

1989-11-01

82

Heat pipe array heat exchanger  

Science.gov (United States)

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

83

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

Austegard, Anders

1997-12-31

84

Multidimensional numerical modeling of heat exchanges  

International Nuclear Information System (INIS)

A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchanges 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 premeability 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, 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-phased on the shell side and may undergo phase-change in the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reaction (LMFBR) intermediate heat exchanges (IHX) and steam generators (SG). The analytical model predictions are compared with three sets of test data (one for IHX and two for SG) and favorable results are obtained, thus providing a limited validation of the model

1982-01-01

85

Use of crude oil fouling threshold data in heat exchanger design  

Energy Technology Data Exchange (ETDEWEB)

The existence of a 'threshold' below which chemical reaction fouling of heat transfer surfaces by crude oil does not occur has been identified by Ebert and Panchal [Fouling Mitigation of Industrial Heat-Exchange Equipment, Begell House, 1997, 451-460] and clearly demonstrated by Knudsen et al. [Understanding Heat Exchanger Fouling and its Mitigation, Begell House, 265-272]. This phenomenon has important implications for the design and operation of heat exchangers in refinery pre-heat trains used for the processing of crudes. In this paper we show how a consideration of the fouling threshold condition can be incorporated into the design procedures for shell-and-tube heat exchangers. We then proceed to show how fouling can be mitigated through attention to heat exchanger design, particularly the choice of configuration. The cost of improperly designed units, based on the conventional use of 'fouling factors', is demonstrated. (author)

Polley, G.T. [Ulverston, Cumbria (United Kingdom); Wilson, D.I.; Yeap, B.L. [University of Cambridge, (United Kingdom). Department of Chemical Engineering; Pugh, S.J. [ESDU International plc, London (United Kingdom)

2002-07-01

86

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

87

Simulation of shell-and-tube condensers of the refrigerating machines with superheated and subcooled refrigerant  

International Nuclear Information System (INIS)

Opposite to many authors who found the simulation of the shell-and-tube condensers on the condensing process only, in this work all thermodynamic processes which appear such as: the process of cooling the superheated refrigerant to the saturated vapor, the process of condensation and option with subcooling are considered. A selection of heat transfer equations is made corresponding to the processes, a mathematical model and adequate computer programme are composed. The functioning of this programme is presented on a concrete example. A computer programing knowledge for the using programme is not necessary. Neither is a programme support. (author)

1994-01-01

88

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.

2014-02-01

89

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

2008-01-01

90

Woven heat exchanger  

Science.gov (United States)

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

91

Fouling in plate heat exchangers: An economic viewpoint  

Energy Technology Data Exchange (ETDEWEB)

Fouling is the formation of undesired deposits on heat transfer surfaces and is one of the major unresolved problems in heat transfer. In New Zealand, fouling related costs are around US$35 million/year. This amount represents 0.15 percent of New Zealand`s gross national product. As a consequence, it is essential to minimise these costs. Plate heat exchangers are usually economically better to use than tubular (shell and tube, double pipe) heat exchangers because they have higher heat transfer and they tend to foul less. However, results presented in this paper suggest that the existing design practices for plate heat exchangers need to be improved to realize their full potential under fouling conditions. It is also shown experimentally that, in some cases, increased flow resistance can cause a plate heat exchanger to perform uneconomically even though it fouls less. It is shown that fouling related costs can be reduced by designing plate heat exchangers using correct fouling factors and also using appropriate fouling mitigation methods. (author). 4 tabs., 10 refs.

Bansal, B.; Mueller-Steinhagen, H. [Auckland Univ. (New Zealand); Bannister, P. [Energy Research Otago Ltd., Dunedin (New Zealand)

1995-12-31

92

European contribution to heat exchanger design/performance: HTFS research and computer programs. Final report. [SCON4 and CEMP1  

Energy Technology Data Exchange (ETDEWEB)

The performance of selected HTFS computer program in solving example heat exchanger design/performance situations is evaluated. In addition, the specific inputs required by the program are presented to give an idea of the amount of detail the user must supply concerning the heat transfer system. Comments on the versatility of each program and technical details necessary for running each program are also provided. The computer programs examined rate the performance of shell-and-tube type condensers and plate-fin heat exchangers.

Lang, C.; Skrovanek, T.

1979-01-01

93

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

94

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

International Nuclear Information System (INIS)

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

2012-09-01

95

Effect of heat transfer correlations of a channel sodium flow on thermal sizing of sodium-to-sodium heat exchangers  

International Nuclear Information System (INIS)

A sodium-to-sodium heat exchanger has been widely used in a sodium-cooled fast reactor as an intermediate heat exchanger (IHX) or a decay heat exchanger (DHX). It is basically a shell-and-tube type counter-current flow heat exchanger, and sodium flows along the tube bundles on the shell-side of the heat exchanger. An accurate prediction of a heat transfer performance is very important for the heat exchanger thermal sizing in a sodium-cooled fast reactor (SFR) design application. To this end, a proper heat transfer coefficient for the appropriate design conditions should be provided for a better design of sodium heat exchangers. However, the experimental correlations for a heat transfer of liquid metal are very rare in the literature and they have large uncertainties since the experiment is very expensive and difficult. The most difficult thing is that the differences among the correlations are so serious that it is difficult to decide which correlation should be used for a particular flow situation. In the present study, we surveyed the conventional heat transfer correlations for single-phase liquid metal flows in a heat exchanger design. The thermal sizing results of sodium heat exchangers with respect to the Nusselt (Nu) number correlations were quantitatively discussed

2010-10-01

96

Direct fired heat exchanger  

Science.gov (United States)

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

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

1986-01-01

97

Potable water heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

This patent describes an indirectly heated potable water heater heated by boiler water providing a high output flow rate with complete safety, comprising, an outer heated boiler water tank, one or more vented metal sheet heat exchangers contained within the tank and heated by the boiler water. The one or more sheet heat exchangers are connected to vented pipes, whereby a highly efficient high flow rate potable water heater is provided.

Lauderdale, R.J.

1986-12-30

98

Wound tube heat exchanger  

Science.gov (United States)

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

Ecker, Amir L. (Duncanville, TX)

1983-01-01

99

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

100

COMMIX code thermal hydraulic analysis of the SNR-300 intermediate heat exchanger  

International Nuclear Information System (INIS)

This paper presents the results of a thermal hydraulic analysis performed on a 85Mwt sodium-to-sodium heat exchanger for the SNR-300 breeder reactor plant at Kalkar, West Germany. The heat exchanger under consideration is of the shell-and-tube type with the primary reactor sodium on the shell side and the secondary sodium on the tube side of the unit. In order to assure the structural integrity of this intermediate heat exchanger under a wide range of plant operating conditions, a detailed three-dimensional thermal hydraulic analysis was conducted with the use of a multi-dimensional thermal hydraulic analysis code COMMIX-HX. Two steady-state (full load and 6% load) and one transient (plant scram) operating conditions were analyzed. The results of the analysis and comparisons with experimental data are discussed in the paper

1985-01-01

 
 
 
 
101

Heat exchanger for heat production  

International Nuclear Information System (INIS)

The description is given of a heat exchanger of the kind in which a primary fluid, flowing in a bundle of parallel tubes which are connected, at least at their lower end, to a tube plate, exchanges its heat with a secondary fluid flowing around the tubes inside an outer casing. Each tube has, at least in the middle part of the exchanger, the shape of a portion of a circle with a central angle less than or equal to 900, and the bottom tube plate which is substantially normal at the lower ends of the tubes has an angle of not less than 450 with the horizontal

1976-01-01

102

Nature's Heat Exchangers.  

Science.gov (United States)

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

Barnes, George

1991-01-01

103

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

2001-01-01

104

Microscale Regenerative Heat Exchanger  

Science.gov (United States)

The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.

Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

2006-01-01

105

Heat and mass exchanger  

Science.gov (United States)

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

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

2011-06-28

106

Selection of the air heat exchanger operating in a gas turbine air bottoming cycle  

Science.gov (United States)

A gas turbine air bottoming cycle consists of a gas turbine unit and the air turbine part. The air part includes a compressor, air expander and air heat exchanger. The air heat exchanger couples the gas turbine to the air cycle. Due to the low specific heat of air and of the gas turbine exhaust gases, the air heat exchanger features a considerable size. The bigger the air heat exchanger, the higher its effectiveness, which results in the improvement of the efficiency of the gas turbine air bottoming cycle. On the other hand, a device with large dimensions weighs more, which may limit its use in specific locations, such as oil platforms. The thermodynamic calculations of the air heat exchanger and a preliminary selection of the device are presented. The installation used in the calculation process is a plate heat exchanger, which is characterized by a smaller size and lower values of the pressure drop compared to the shell and tube heat exchanger. Structurally, this type of the heat exchanger is quite similar to the gas turbine regenerator. The method on which the calculation procedure may be based for real installations is also presented, which have to satisfy the economic criteria of financial profitability and cost-effectiveness apart from the thermodynamic criteria.

Chmielniak, Tadeusz; Czaja, Daniel; Lepszy, Sebastian

2013-12-01

107

Support for heat exchangers  

International Nuclear Information System (INIS)

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

1979-01-01

108

Thin film heat exchanger  

International Nuclear Information System (INIS)

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

1976-01-01

109

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

110

Improvement of high temperature heat exchanger efficiency by inserted porous material, (3)  

International Nuclear Information System (INIS)

In the 1st paper, improvement of shell and tube heat exchanger efficiency by inserted wound wire net layers (WNL) around the tube bundle is investigated. And in the 2nd paper, the effect of the WNL inserted in a preheating shell and single tube heat exchanger, where shell wall is designed to be cooled by the secondary gas which in turn is preheated, is revealed. In the present study, following the 2nd paper, the preheating type heat exchanger with 12-tube bundle is examined; results show marked improvement in heat exchanger efficiency, which is essentially the same as those of the previous paper. By the WNL inserted exchanged heat in the preheating section decreases, however that in the tube bundle section increases to more than overcome this decrease and the total exchanged heat increases by 14 ? 18 %. Comparison of heat exchanger performances examined in the preceding works and in the present study is also made. It is found that the effectiveness for the present heat exchanger is the highest. (author)

1986-01-01

111

Improvements to heat exchangers  

International Nuclear Information System (INIS)

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

1974-08-23

112

Heat exchanger design handbook  

CERN Document Server

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

113

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

114

Lightweight Long Life Heat Exchanger.  

Science.gov (United States)

A shuttle orbiter flight configuration aluminum heat exchanger was designed, fabricated, and tested. The heat exchanger utilized aluminum clad titanium composite parting sheets for protection against parting sheet pin hole corrosion. The heat exchanger, w...

E. K. Moore

1976-01-01

115

A corrosive resistant heat exchanger  

Science.gov (United States)

A corrosive and erosive 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 pumped 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. 3 figs., 3 tabs.

Richlen, S.L.

1987-08-10

116

Proactive heat exchanger program  

International Nuclear Information System (INIS)

This paper describes the proactive heat exchanger program at Pickering Nuclear Generating Station. The objectives, methodology, benefits and costs are presented. Examples of initial results are included. 4 refs, 2 figs

1992-11-22

117

Plate heat exchanger  

International Nuclear Information System (INIS)

A plate heat exchanger is described, comprising multiple flat parallel comportments, each one between two neighbouring plates, these compartments being separated by narrow spaces through which a high pressure fluid flows, in normal operation, exchanging calories through the plates with another low pressure fluid passing through the compartments

1977-01-01

118

Improvements in heat exchangers  

International Nuclear Information System (INIS)

The invention concerns improvements for heat exchangers for e.g. reactor-cooling systems using liquid sodium and water as primary and secondary coolants. The construction is designed so as to base the fluid flow of the sodium on natural convection where stagnation of the sodium flow and corrosion by impurities at the bottom of the heat exchanger are avoided. In addition, a fast leakage-warning system is possible in this construction

1974-08-23

119

Heat exchanger cleaning  

International Nuclear Information System (INIS)

A survey covers the various types of heat-exchange equipment that is cleaned routinely in fossil-fired generating plants, the hydrocarbon-processing industry, pulp and paper mills, and other industries; the various types, sources, and adverse effects of deposits in heat-exchange equipment; some details of the actual procedures for high-pressure water jetting and chemical cleaning of some specific pieces of equipment, including nuclear steam generators. (DN)

1980-05-01

120

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

International Nuclear Information System (INIS)

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

1991-01-01

 
 
 
 
121

Counterflow Regolith Heat Exchanger  

Science.gov (United States)

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

Zubrin, Robert; Jonscher, Peter

2013-01-01

122

Thermosyphon heat exchanger  

Science.gov (United States)

Report summarizes final development, testing, and certification of pumpless, liquid-to-air heat exchanger for solar heating. System requires blower but no pump in water loop. Output is 35,000 Btu/hr when water temperature is 49 C.

Hankins, J. D.

1980-01-01

123

Heat exchange enhancement structure  

International Nuclear Information System (INIS)

A passive heat exchange enhancement structure which operates by free convection includes a flat mounting portion having a plurality of integral fins bent outwardly from one side edge thereof. The mounting portion is securable around a stovepipe, to a flat surface or the like for transferring heat from the pipe through the fins to the surrounding air by rotation-enhanced free convection

1980-01-01

124

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

125

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 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 summarized

1992-01-01

126

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

127

Update heat exchanger designing principles  

International Nuclear Information System (INIS)

Update heat exchanger design principles are analysed. Different coolant pattern in a heat exchanger are considered. It is suggested to rationally organize flow rates irregularity in it. Applying on heat exchanger designing measures on using really existing temperature and flow rate irregularities will permit to improve heat exchanger efficiency. It is expedient in some cases to artificially produce irregularities. In this connection some heat exchanger design principles must be reviewed now

1985-11-01

128

High temperature heat exchanger  

International Nuclear Information System (INIS)

The high temperature heat exchanger described is made up of a stack of blocks forming the body of the exchanger itself, and the end connecting blocks in which the primary and secondary ducts are drilled. Each end block has at least two surfaces inclined with respect to each other, on which the primary and secondary ducts respectively emerge. These surfaces are inter-joined and support a primary and secondary fluid separation piece

1975-01-01

129

Plate heat exchanger  

International Nuclear Information System (INIS)

The heat exchanger described is of the plate type. It includes, at least, one exchange bundle formed by a set of compartments side by side, each compartment being composed of two superimposed metal sheets, and separate inlet and outlet manifolds for the coolant circulating in that compartment. The manifolds of a given compartment substantially fill two half widths on opposite sides, at the ends of the compartment

1974-01-01

130

Microgravity condensing heat exchanger  

Science.gov (United States)

A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches 90.degree.. Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)

2011-01-01

131

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

132

Heat exchanger panel  

Science.gov (United States)

The present invention relates to a heat exchanger panel which has broad utility in high temperature environments. The heat exchanger panel has a first panel, a second panel, and at least one fluid containment device positioned intermediate the first and second panels. At least one of the first panel and the second panel have at least one feature on an interior surface to accommodate the at least one fluid containment device. In a preferred embodiment, each of the first and second panels is formed from a high conductivity, high temperature composite material. Also, in a preferred embodiment, the first and second panels are joined together by one or more composite fasteners.

Warburton, Robert E. (Inventor); Cuva, William J. (Inventor)

2005-01-01

133

Heat exchanger with heater  

International Nuclear Information System (INIS)

The subject of this invention is a heat exchanger with vertical tubes and heating enabling a distinctly improved thermo-dynamic efficiency to be obtained by placing the heater at the bottom end of the vaporiser, in other words near the primary fluid outlet, the secondary fluid flowing counter-current whilst ensuring a good degree of integration of the system as a whole (vaporiser and heater)

1976-01-01

134

Direct contact liquid-liquid heat exchanger for solar heated and cooled buildings. Final report, January 1, 1979-May 30, 1980  

Energy Technology Data Exchange (ETDEWEB)

The technical and economic feasibility of using a direct contact liquid-liquid heat exchanger (DCLLHE) storage unit in a solar heating and cooling system is established. Experimental performance data were obtained from the CSU Solar House I using a DCLLHE for both heating and cooling functions. A simulation model for the system was developed. The model was validated using the experimental data and applied in five different climatic regions of the country for a complete year. The life-cycle cost of the system was estimated for each application. The results are compared to a conventional solar system, using a standard shell-and-tube heat exchanger. It is concluded that while thare is a performance advantage with a DCLLHE system over a conventional solar system, the advantage is not sufficiently large to overcome slightly higher capital and operating costs for the DCLLHE system.

Karaki, S.; Brothers, P.

1980-06-01

135

Cryogenic heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger for vaporizing a cryogenic fluid comprises a conduit through which the fluid is passed and a heat transfer sleeve surrounding the conduit. The sleeve is comprised of two heat transfer sections, each having a central arcuate portion in close partial circumferential contact with the conduit, a plurality of radially extending heat transfer fins, and a pair of interlocking members located on the fins at a predetermined distance from the central portion for assembling the two sections together around the conduit. In the assembled state, the resiliency of the fins on which the interlocking members are located provides a continuous clamping for which permits the two central portions to maintain intimate contact with the conduit as it undergoes thermal contraction, while also facilitating assembly and disassembly of the two sections. Each heat transfer fins is also provided with a corrugated or rippled surface near its tip to increase its surface area and the rate of heat transfer and vaporization.

Lutjens, R. D.; Duron, P. P.

1984-12-11

136

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

137

Tubular heat exchanger  

International Nuclear Information System (INIS)

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

1975-08-20

138

Double barrier heat exchanger  

International Nuclear Information System (INIS)

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

1981-08-10

139

Heat exchanger classification  

International Nuclear Information System (INIS)

The heat exchanger is the result of a combination of two half-exchangers, and hence of the combination of the conditions imposed on each of them, combination implying a specific type of construction. This reasoning led to the adoption of the type of construction as the initial criterion. According to type, the mean limit values are indicated for pressure, temperature and area, and it must be considered that these limits do not all act together. These indications enable comparisons between the possibilities of different types of exchangers. Whereas for pressure and temperature, these comparisons are immediate, insofar as area is concerned, it is necessary to account for the type of surface, tubes or plates, and its arrangement, irrespective of mechanical and maintenance conditions, for example. It must also be noted that divergencies sometimes exist between the limits guaranteed by builders and those allowed by major users

1971-06-16

140

Process heat transfer principles, applications and rules of thumb  

CERN Multimedia

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

Serth, Robert W

2014-01-01

 
 
 
 
141

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

International Nuclear Information System (INIS)

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

2012-09-01

142

Heat exchanger tube tool  

International Nuclear Information System (INIS)

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

1976-01-01

143

A proposal for the use of a very high temperature ceramic heat exchanger in gas turbine power production  

Energy Technology Data Exchange (ETDEWEB)

A highly efficient gas turbine plant is considered which uses ceramic heat exchanger components to take advantage of the very high turbine inlet temperatures available today. The materials used in the heat exchangers may have temperatures in excess of 1,000 C. Most Advanced Power Production Plant have the process fluid (steam or gases) usually enclosed inside tubes surrounded by combustion gases. A heat exchanger is proposed that has combustion gases on the inside of ceramic tubes in a shell and tube heat exchanger arrangement. The pressurized working fluid flows over the outside of the tubes in the shell. The ceramic tubes are thus kept in compression by the high pressure of this process fluid, utilizing the impressive resistance of ceramics to compressive force. The system described could be used in an exhaust-gas heat exchanger gas turbine power cycle to raise the thermal efficiency to approximately 65% (about 10% above that obtainable by conventional Combined Cycle Power Plant). The low pressure exhaust gases (say 1,000 C) from the secondary turbine are fed into the ceramic heat exchanger to heat the air from the high pressure compressor. This high temperature air is then fed to the combustor to provide gases at around 1,260 C/5 b for the turbines. The exhaust energy of the heat exchanger (200 C) could be used to raise steam for district heating purposes giving an excellent overall use of energy.

Smyth, R. [Univ. of Sheffield (United Kingdom). Dept. of Mechanical Engineering

1997-12-31

144

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

Science.gov (United States)

...10-20 Patches in shells and tube sheets. (a) Unreinforced...of the hole and shall have a thickness equal to the thickness of the plate to which it is...are met. (b) Portions of tube sheets which have...

2009-10-01

145

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

146

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 Bi(0.5)Sb(1.5)Te3/Ni provides a promising solution. The Bi(0.5)Sb(1.5)Te3/Ni tube allows tightly sealed fluid flow inside itself, and operates in analogy with the standard shell and tube heat exchanger. We show that it achieves perfect balance between efficient heat exchange and high-power generation with a heat transfer coefficient of 4.0 kW/m(2)K and a volume power density of 10 kW/m(3) using low-grade heat sources below 100°C. The Bi(0.5)Sb(1.5)Te3/Ni tube thus serves as a power generator and a heat exchanger within a single unit, which is advantageous for developing new cogeneration systems in factories, vessels, and automobiles where cooling of excess heat is routinely carried out. PMID:23511347

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

2013-01-01

147

Heat exchanger control system  

International Nuclear Information System (INIS)

Measured values for primary temperature exit, a heat transfer tube temperature and secondary exit temperature are feed-back respectively and amounts of feed-back are collected together, to calculate a set value for a secondary fluid flow rate. The secondary fluid flow rate is controlled based on the set value. Since the control deviation for the secondary fluid is increased only with the control for the first fluid, the control deviation for the secondary flow rate is also feed-back to make them compatible. In addition, since the temperature change in the heat exchanger is shown by the flow of the fluid as a temperature change at the exit, the heat transfer tube temperature at the central portion thereof is detected and the control deviation is feed-back, to control the temperature change at the inside. Then the deviation of the temperature is scarcely caused, thereby enabling to change the reactor power following the scheduled value. (N.H.)

1993-07-14

148

Evaluation of structural integrity and heat exchange efficiency for dimpled tube type EGR cooler  

Energy Technology Data Exchange (ETDEWEB)

Most of vehicle manufacturers have applied Exhaust Gas Recirculation (EGR) system to the development of diesel engines in order to obtain the high thermal efficiency without NOX and Particulate Matter (PM) emitted from the engine. EGR system, which reflow a cooled exhaust gas from vehicles burning diesel as fuel to a combustion chamber of engine, has been used to solve this problem. In order to confirm the safety of the EGR system, finite element analysis was carried out. The safety of EGR system against temperature variation in the shell and tubes was evaluated through the thermal and structural analysis, and the modal analysis using ANSYS was also performed. Finally, the performance of EGR system was verified through the experiment and numerical simulation using effectiveness-NTU method. Program for the estimation of the heat exchange efficiency of the EGR system with regard to the dimpled tube shape was developed.

Seo, Young Ho; Lee, Hyun Min; Park, Jung Won; Ku, Tae Wan; Kim, Jeong; Kang, Beom Soo [Pusan National Univ., Busan (Korea, Republic of)

2008-07-01

149

Liquid/liquid heat exchanger  

Science.gov (United States)

Conceptual design for heat exchanger, utilizing two immiscible liquids with dissimilar specific gravities in direct contact, is more efficient mechanism of heat transfer than conventional heat exchangers with walls or membranes. Concept could be adapted for collection of heat from solar or geothermal sources.

Miller, C. G.

1980-01-01

150

Fault-Tolerant Heat Exchanger  

Science.gov (United States)

A compact, lightweight heat exchanger has been designed to be fault-tolerant in the sense that a single-point leak would not cause mixing of heat-transfer fluids. This particular heat exchanger is intended to be part of the temperature-regulation system for habitable modules of the International Space Station and to function with water and ammonia as the heat-transfer fluids. The basic fault-tolerant design is adaptable to other heat-transfer fluids and heat exchangers for applications in which mixing of heat-transfer fluids would pose toxic, explosive, or other hazards: Examples could include fuel/air heat exchangers for thermal management on aircraft, process heat exchangers in the cryogenic industry, and heat exchangers used in chemical processing. The reason this heat exchanger can tolerate a single-point leak is that the heat-transfer fluids are everywhere separated by a vented volume and at least two seals. The combination of fault tolerance, compactness, and light weight is implemented in a unique heat-exchanger core configuration: Each fluid passage is entirely surrounded by a vented region bridged by solid structures through which heat is conducted between the fluids. Precise, proprietary fabrication techniques make it possible to manufacture the vented regions and heat-conducting structures with very small dimensions to obtain a very large coefficient of heat transfer between the two fluids. A large heat-transfer coefficient favors compact design by making it possible to use a relatively small core for a given heat-transfer rate. Calculations and experiments have shown that in most respects, the fault-tolerant heat exchanger can be expected to equal or exceed the performance of the non-fault-tolerant heat exchanger that it is intended to supplant (see table). The only significant disadvantages are a slight weight penalty and a small decrease in the mass-specific heat transfer.

Izenson, Michael G.; Crowley, Christopher J.

2005-01-01

151

High heat flux single phase heat exchanger  

Science.gov (United States)

This paper presents the results obtained to date in a program to develop a high heat flux, single-phase heat exchanger for spacecraft thermal management. The intended application is a net generation interface heat exchanger to couple the crew module water thermal bus to the two-phase ammonia main thermal bus in the Space Station Freedom. The large size of the interface heat exchanger is dictated by the relatively poor water-side heat transfer characteristics. The objective of this program is to develop a single-phase heat transfer approach which can achieve heat fluxes and heat transfer coefficients comparable to those of the evaporation ammonia side. A new heat exchanger concept has been developed to meet these objecties. The main feature of this heat exchanger is that it can achieve very high heat fluxes with a pressure drop one to two orders of magnitude lower than those of previous microchannel or jet impingement high heat flux heat exchangers. This paper describes proof-of-concept experiments performed in air and water and presents analytical model of the heat exchanger.

Valenzuela, Javier A.; Izenson, Michael G.

1990-01-01

152

Cryogenic regenerative heat exchangers  

CERN Document Server

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

Ackermann, Robert A

1997-01-01

153

Tube bundle heat exchanger  

International Nuclear Information System (INIS)

The heat exchanger described includes a combined heavy external structure composed of an outside cylindrical envelope fixed by its ends to an annular inlet head and an annular head for removing one of the fluids, an internal light structure then fitted in the heavy structure and formed by an annular bundle of tubes inserted and welded by their ends into holes drilled in the end plates and arranged in concentric layers leaving a large central passage accessible for fitting up. It can be used as steam generator in PWR and LMFBR type reactors

1974-01-01

154

The Design of Heat Exchangers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

2011-01-01

155

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

2011-09-01

156

Hybrid Heat Exchangers  

Science.gov (United States)

A hybrid light-weight heat exchanger concept has been developed that uses high-conductivity carbon-carbon (C-C) composites as the heat-transfer fins and uses conventional high-temperature metals, such as Inconel, nickel, and titanium as the parting sheets to meet leakage and structural requirements. In order to maximize thermal conductivity, the majority of carbon fiber is aligned in the fin direction resulting in 300 W/m.K or higher conductivity in the fin directions. As a result of this fiber orientation, the coefficient of thermal expansion (CTE) of the C-C composite in both non-fiber directions matches well with the CTE of various high-temperature metal alloys. This allows the joining of fins and parting sheets by using high-temperature braze alloys.

Tu, Jianping Gene; Shih, Wei

2010-01-01

157

The effect of flexible tube vibration on pressure drop and heat transfer in heat exchangers considering viscous dissipation effects  

Energy Technology Data Exchange (ETDEWEB)

The pressure drop and heat transfer coefficient in tube bundle of shell and tube heat exchangers are investigated considering viscous dissipation effects. The governing equations are solved numerically. Because of temperature-dependent viscosity the equations should be solved simultaneously. The flexible tubes vibration is modeled in a quasi-static method by taking the first tube of the row to be in 20 asymmetric positions with respect to the rest of the tubes which are assumed to be fixed and time averaging the steady state solutions corresponding to each one of these positions.The results show that the eccentricity of the first tube increases pressure drop and heat transfer coefficients significantly comparing to the case of rigid tube bundles, symmetrically placed. In addition, these vibrations not only compensate the effect of viscous dissipations on heat transfer coefficient but also increase heat transfer coefficient. The constant viscosity results obtained from our numerical method have a good agreement with the available experimental data of constant viscosity for flexible tube heat exchangers. (orig.)

Shokouhmand, H.; Sangtarash, F. [University of Tehran, Department of Mechanical Engineering, Faculty of Engineering, Tehran (Iran)

2008-10-15

158

Two phase heat exchanger symposium  

International Nuclear Information System (INIS)

This book compiles the papers presented at the conference on the subject of heat transfer mechanics and instrumentation. Theoretical and experimental data are provided in each paper. The topics covered are: temperature effects of steel; optimization of design of two-phase heat exchanges; thermosyphon system and low grade waste heat recovery; condensation heat transfer in plate heat exchangers; forced convective boiling; and performance analysis of full bundle submerged boilers

1985-08-04

159

Preliminary Thermal Stress Analysis for Intermediate Heat Exchanger of Prototype SFR  

Energy Technology Data Exchange (ETDEWEB)

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

Kim, Sungkyun; Kim, Seokhoon; Lee, Jaehan; Koo, Gyeonghoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-05-15

160

Anisotroping porous structure heat exchanger  

International Nuclear Information System (INIS)

The object of this invention is a heat exchanger with an anisotropic porous structure. Specifically, this invention concerns a heat exchanger for example, between a gas and a liquid that utilises, for the flow of one of the fluids, a containment at leats partly filled with a porous structure for improving the thermal exchanges between the hot primary fluid and the second fluid to be heated

1980-01-01

 
 
 
 
161

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

162

Next Generation Microchannel Heat Exchangers  

CERN Document Server

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

Ohadi, Michael; Dessiatoun, Serguei; Cetegen, Edvin

2013-01-01

163

Heat exchanger leakage problem location  

Science.gov (United States)

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

Hej?ík, Ji?í; Jícha, Miroslav

2012-04-01

164

Heat exchanger leakage problem location  

Directory of Open Access Journals (Sweden)

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

Jícha Miroslav

2012-04-01

165

High Temperature Heat Exchanger Project  

Energy Technology Data Exchange (ETDEWEB)

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

Anthony E. Hechanova, Ph.D.

2008-09-30

166

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

167

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

168

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

169

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

170

A heat exchanger expert system  

Energy Technology Data Exchange (ETDEWEB)

This article describes a real-time expert system for detecting and diagnosing faults in a 20-kilowatt (kW) microwave transmitter heat exchanger. Expert systems enhance operator productivity by quickly identifying problems and recommending appropriate solutions, or predicting i pending problems that have not yet occurred. The heat exchanger expert system has been tested and debugged. Applications and extensions of the expert system to heating, air-conditioning, and ventilating problems are discussed.

Bagby, D.G.; Cormier, R.A. (Jet Propulsion Lab., California Inst. of Technology, Pasadena, CA (US))

1989-01-01

171

Electroforming thin channel heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

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

Steffani, C.P.

1991-06-01

172

WASTE HEAT RECOVERY FROM BOILER OF LARGE-SCALE TEXTILE INDUSTRY  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 p...

2013-01-01

173

Heat pipe heat exchanger analytic design model  

Energy Technology Data Exchange (ETDEWEB)

This paper presents an analytical model to predict, as functions of operating characteristics and geometry, the overall thermal performance and pressure drops of a gas-gas heat exchanger using a closed two-phase thermosyphon. First, the thermal efficiency of a generic rank is correlated to the overall heat transfer characteristics. The correlations are then reviewed to estimate the gas pressure drops and heat transfer coefficients both outside and inside the closed two-phase thermosyphon. Finally, the gas temperatures at each rank inlet, the efficiency of the heat exchanger, and the gas pressure drops are correlated to the efficiencies of the various ranks.

Niro, A. (Politecnico di Milano, Milan (Italy). Dipt. di Energetica)

1991-09-01

174

Cost effective heat exchanger network design with mixed materials of construction  

International Nuclear Information System (INIS)

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

2004-01-01

175

Heat exchangers for HHT plants  

International Nuclear Information System (INIS)

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.)

1979-01-01

176

Direct-contact heat exchanger  

Science.gov (United States)

The working principle of direct contact heat exchanger, where heat transfer takes place between two immiscible fluids coming into direct contact, is described. Typical direct contact devices are outlined. A better understanding of the principles involved and the development of computational models for multiphase subsytems are concluded as stimulus for direct contact heat and mass transfer applications.

Bricard, A.

177

Explosive plugging of heat exchangers  

International Nuclear Information System (INIS)

The mechanism and development of explosive welding and particularly the application to tube-to-tubeplate welding is briefly reviewed. The need for plugging of heat exchangers in the power generating industry and the requirement for producing a high integrity weld are discussed. Details are given of the explosive plugging system developed for the reheater heat exchanger of the prototype fast reactor (PFR), including data on weld lengths and distortion of adjoining holes. Results of destructive and nondestructive tests on trial plugging of a seven hole array are given. The system described has been successfully applied to an actual heat exchanger and the procedure followed is briefly discussed

1972-09-17

178

Heat exchanger with ceramic elements  

Science.gov (United States)

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

179

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

180

Heat exchange apparatus utilizing thermal siphon pipes  

Energy Technology Data Exchange (ETDEWEB)

A heat exchange apparatus is descirbed in which each of a plurality of thermal siphon pipes has an upper portion extending in an upper heat exchange section and a lower portion extending in a lower heat exchange section. Each pipe is closed at its ends and contains a heat transfer fluid so that when a hot fluid is passed through the lower heat exchange section, the heat is transferred from the hot fluid to the heat exchange fluid. A cool fluid is passed through the upper heat exchange section to remove the heat from the heat exchange fluid.

Daman, E.L.; Kunsagi, L.

1980-10-07

 
 
 
 
181

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

182

Interface Heat Exchanger Heat Transfer Element Test.  

Science.gov (United States)

The Interface Heat Exchanger Coldplate, Part Number 58A831057, is a two-circuit coldplate for the Gemini B coolant system. The purpose of the test was to determine the heat transfer coefficient from the interface surface of the coldplate to the coolant fl...

1968-01-01

183

Tubular heat exchanger for a nuclear reactor  

International Nuclear Information System (INIS)

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

184

Designing heat exchangers for process heat reactors  

International Nuclear Information System (INIS)

A brief account is given of the IAEA specialist meeting on process heat applications technology held in Julich, November 1979. The main emphasis was on high temperature heat exchange. Papers were presented covering design requirements, design construction and prefabrication testing, and selected problems. Primary discussion centered around mechanical design, materials requirements, and structural analysis methods and limits. It appears that high temperature heat exchanges design to nuclear standards, is under extensive development but will require a lengthy concerted effort before becoming a commercial reality. (author)

1980-01-01

185

Liquid droplet heat exchanger studies  

International Nuclear Information System (INIS)

Recent studies at the University of Washington (Bruckner, et al., 1982, 1984, 1985) and elsewhere (Taussig, et al., 1985) have addressed the feasibility of direct contact heat exchanger concepts, such as the liquid droplet heat exchanger (LDHX), for space power systems. In the LDHX heat is transferred by direct contact between a recirculating cloud of finely dispersed liquid droplets and a working gas. A critical design requirements of the LDHX is effective separation of the heat exchange media following heat transfer. The principle of the cyclone dust separator, in which particulate matter is separated from a swirling gas by centrifugal forces, offers an effective approach to the problem. A variety of cyclone-based LDHX geometries have been investigated, culminating in a low aspect ratio vortex chamber configuration (Bruckner, et al., 1984, 1985)

1986-01-13

186

Cascade reactor: heat exchanger design  

International Nuclear Information System (INIS)

The authors examined four heat-exchanger concepts: fluid-bed immersed-tube, fluid-bed direct contact, gravity-flow cascade (with helium gas in the interstices), and gravity-flow cascade (with vacuum in the interstices). Heat-transfer models and correlations can be applied with reasonable confidence for the case of a moving granule bed flowing over heat exchanger surfaces that are under vacuum, or with interstitial helium gas. Fluid-bed heat-transfer correlations are also available for immersed-tube heat-exchange surfaces. The secondary fluid can be either helium or water, but for this study, they evaluated the heat exchangers for uniform secondary steam-side conditions of conventional, superheated steam turbine cycles of modern fossil-fired power plants. All concepts use double-walled tubes to minimize tritium permeation into the steam and to reduce the possibility of water leaks into the blanket. They chose granule inlet and outlet temperatures to the heat exchanger as 1200 K and 800 K. The resulting designs are summarized in a table and discussed

1985-06-01

187

Experimental research on heat transfer in a coupled heat exchanger  

Directory of Open Access Journals (Sweden)

Full Text Available The heat exchanger is a devise used for transferring thermal energy between two or more different temperatures. The widespreadly used heat exchanger can only achieve heat exchange between two substances. In this paper, a coupled heat exchanger is proposed, which includes a finned heat exchanger and a double pipe heat exchanger, for multiple heat exchange simultaneously. An experiment is conducted, showing that the average heating capacity increases more than 35%, and the average heating efficiency increases more than 55%, compared with the ordinary air-source heat pump.

Liu Yin

2013-01-01

188

Heat exchanger with immersed tubes  

International Nuclear Information System (INIS)

A heat exchanger made of plunging tubes and separating two circulating fluids (the secondary fluid generally being water) is described. This heat exchanger is of the 'once-through' type but it directly produces superheated steam. This is made possible by a new design of each tube, these tubes being arranged in such a way as to allow internal recycling. In addition, the secondary fluid can come directly from a condenser, without previous re-heating. This design also allows an easy dismantling of the various internal structures for maintenance and control during operation

1975-01-01

189

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

Energy Technology Data Exchange (ETDEWEB)

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

Chang Oh; Eung Kim; Robert Shrake; Mike Patterson

2009-05-01

190

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

International Nuclear Information System (INIS)

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

2009-05-10

191

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

192

Mechanical calculation of heat exchangers  

International Nuclear Information System (INIS)

Many heat exchangers are still being dimensioned at the present time by means of the American TEMA code (Tubular Exchanger Manufacturers Association). The basic formula of this code often gives rise to significant tubular plate thicknesses which, apart from the cost of materials, involve significant machining. Some constructors have brought into use calculation methods that are more analytic so as to take into better consideration the mechanical phenomena which come into play in a heat exchanger. After a brief analysis of these methods it is shown, how the original TEMA formulations have changed to reach the present version and how this code has incorporated Gardner's results for treating exchangers with two fixed heads. A formal and numerical comparison is then made of the analytical and TEMA methods by attempting to highlight a code based on these methods or a computer calculation programme in relation to the TEMA code

1977-10-07

193

OPTIMASI KINERJA HEAT EXCHANGER TABUNG KOSENTRIS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 affe...

Didik Wahjudi

2000-01-01

194

Three-component heat exchanger  

International Nuclear Information System (INIS)

A three-component heat exchanger is proposed in which two media are carried in separate tube systems designed as approximately vertical, concentric, cylindrical (or plane) tube walls arranged in a vessel filled with a stagnant fluid compatible with the two media in such a way that a small clearance is left between the two tube walls. Such heat exchangers can be employed in nuclear power plants equipped with circuits carrying sodium and water(vapor). If the two media have very different enthalpies, the cross section or the arrangement of the different tubes relative to each other is balanced out. A lead-bismuth eutectic is proposed as the contact medium. (UWI)

1975-01-01

195

Vapor/liquid interaction and entrainment in shell-and-tube evaporators  

Energy Technology Data Exchange (ETDEWEB)

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) power plants. In the horizontal tube design, liquid falls from one tube to the next in either a droplet or column mode. A criterion is derived for predicting the transition from the droplet mode to the column mode. Models are developed for predicting the deflection of droplets and columns due to vapor crossflow. Based on an experimental study of drop detachment and breakup, a correlation is established for determining the resulting droplet sizes. For high vapor crossflow velocities, a criterion is presented for predicting the inception of liquid entrainment by a process known as stripping. Based on the foregoing models, conditions are defined under which vapor/liquid interaction and entrainment are important for OTEC evaporators.

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

1978-06-01

196

Heat Exchangers Analysis  

Directory of Open Access Journals (Sweden)

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

S.C. Pang

2013-01-01

197

Optimum control of heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The present paper concems the control of high-performance heat exchangers for hot water service. Some of the basic control theories and their decisively important relationships are analysed from a theoretical point of view. A newly developed control is described, putting the various elements in the design into the perspective of control theory. (orig.)

Benonysson, A. [Danfoss A/S, Nordborg (Denmark); Boysen, H. [Danfoss A/S, Nordborg (Denmark)

1996-09-01

198

Heat exchanger staybolt acceptance criteria  

International Nuclear Information System (INIS)

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

1992-01-01

199

SP-100 Heat Source Heat Exchanger Design  

Science.gov (United States)

A conceptual design for a liquid metal to gas counterflow heat exchanger has been developed for use in the SP-100 Closed Brayton Cycle (CBC) Space Reactor Power System (SRPS). The Heat Source Heat Exchanger (HSHX) is required to transfer 80 kWt from the 1350 K lithium reactor coolant to the He/Xe working fluid of the Brayton Rotating Unit (BRU). Trade studies were performed to select a concept that best meets the performance requirements as well as the mass minimization goals and packaging requirements of the SRPS. The HSHX design is based on state-of-the-art fabrication techniques developed for use in the SP-100 Thermoelectric Converter Assembly (TCA) Heat Exchanger and a previously developed Mini-BRU space power system HSHX. The HSHX is a Nb-lZr finned flat plate assembly fabricated by the Hot Isostatic Process (HIP). The approximate size of the HSHX assembly is a 0.70 m x 0.15 m cross section over its 18 cm active length. The conceptual design meets all thermal-hydraulic and structural design requirements for a five-year mission while weighing less than 50 kg.

Fallas, T. Ted; Desepte, Andrew W.; Hill, Robert J.; Manjarrez, Georgi B.; Solorzano, Enrique R.; Salamah, Samir A.; Yahalom, Raphael

1994-07-01

200

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

 
 
 
 
201

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

International Nuclear Information System (INIS)

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

2004-01-01

202

Application of explosive welding to heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The subject is discussed under the headings: advantages of explosive welding; principle of explosive welding; explosive welding of tubes; metallurgy of explosive welds (micrographs; microhardness); tubular heat exchangers; plugging; sleeving; retubing; construction of new heat exchangers; thermal sleeves.

Arthur, G.

1983-10-01

203

Pressurized bellows flat contact heat exchanger interface  

Science.gov (United States)

Disclosed is an interdigitated plate-type heat exchanger interface. The interface includes a modular interconnect to thermally connect a pair or pairs of plate-type heat exchangers to a second single or multiple plate-type heat exchanger. The modular interconnect comprises a series of parallel, plate-type heat exchangers arranged in pairs to form a slot therebetween. The plate-type heat exchangers of the second heat exchanger insert into the slots of the modular interconnect. Bellows are provided between the pairs of fins of the modular interconnect so that when the bellows are pressurized, they drive the plate-type heat exchangers of the modular interconnect toward one another, thus closing upon the second heat exchanger plates. Each end of the bellows has a part thereof a thin, membrane diaphragm which readily conforms to the contours of the heat exchanger plates of the modular interconnect when the bellows is pressurized. This ensures an even distribution of pressure on the heat exchangers of the modular interconnect thus creating substantially planar contact between the two heat exchangers. The effect of the interface of the present invention is to provide a dry connection between two heat exchangers whereby the rate of heat transfer can be varied by varying the pressure within the bellows.

Voss, Fred E. (inventor); Howell, Harold R. (inventor); Winkler, Roger V. (inventor)

1990-01-01

204

Liquid metal/air heat exchanger  

International Nuclear Information System (INIS)

The aim of the invention is a liquid metal/air heat exchanger which can resist to thermal expansion of tubes for which a supporting system is provided in the present case; this supporting system does not involve excessive stresses. Such heat exchangers apply to LMFBR type reactors. They are used as emergency heat exchangers when there is a failure of the reactor cooling circuits to cool the primary liquid sodium, or as heat exchangers in test or experimental circuits of reactors

1984-05-25

205

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

206

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

Energy Technology Data Exchange (ETDEWEB)

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

Culver, G.

1990-11-01

207

Cryogenic Heat Exchanger with Turbulent Flows  

Science.gov (United States)

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

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

2012-01-01

208

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.  

Science.gov (United States)

...false Cardiopulmonary bypass heat exchanger. 870.4240 Section 870...4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting...

2010-04-01

209

Experimental investigation of single-phase, condensation, and flow boiling heat transfer for a spirally fluted tube  

International Nuclear Information System (INIS)

This paper reports on a spirally fluted tube that was tested in a vertically oriented shell-and-tube heat exchanger in both condensing and evaporating service. The heat exchanger showed substantial improvement in performance over that expected from a comparable exchanger with plain tubes. The condensation tests were run with working fluids of ammonia and R-114 condensing on the shell side of the heat exchanger. The boiling tests were run with R-11 boiling on the tube side in upward forced convection; heat was supplied by steam condensing on the shell side

1992-01-01

210

Heat exchangers for district energy systems  

Energy Technology Data Exchange (ETDEWEB)

The three types of heat exchangers which are suitable for district heating applications were described. The three types which are dominating the market are: (1) the plate and frame heat exchanger, (2) the shell and coil heat exchanger, and (3) the brazed plate heat exchanger. The advantages and special features of each type were summarized. ELGE AB is a manufacturer of these heat exchangers and has sold them mainly to the Scandinavian market, but some units also to the United States and Canada. The fouling phenomenon associated with heat exchangers, and the factors affecting fouling, such as temperature, distribution, turbulence, velocity, flow, surface finish and water quality, were described. Recommendations were made as to how the life-cycle cost of the heat exchanger could be improved.

Dahlberg, M. [ELGE AB, Linkoping (Sweden)

1995-12-31

211

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

212

Analysis Of The Efficiency Improvement Of The Kartini Reactor's Heat Exchanger  

International Nuclear Information System (INIS)

Analysis of the efficiency improvement of the shell and tube type of the Kartini reactor's Heat Exchanger (HE) have been carried out after the flow direction system was modified from the parallel flow to the counter flow system. The HE was tested by operating the reactor at the power level of 100 k W, until the temperature of the water coolant reached the steady state condition. The efficiency and other HE's parameters was investigated by using the SIMULTANmethod. From the experiment it is known that the inlet and outlet primary and secondary water coolants are Ti = 38oC, To = 35oC, ti 32oC and to = 33oC respectively. The investigation and analysis show that that HE's efficiency is ?= 45,5 % due to U a= 674,79 W/m K, LMT = 3,27 and NTU 0,835. From the analysis can be concluded that the increase of the HE's efficiency is 2.5 % compared to parallel flow and the decrease is 6.7% compared to the HE's efficiency as soon as after having been cleaned in 1994

1996-04-01

213

Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes  

Energy Technology Data Exchange (ETDEWEB)

A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided and includes a steam drum disposed adjacent the fluidized bed and a series of tubes connected at one end to the steam drum. A portion of the tubes are connected to a water drum and in the path of the air and the gaseous products of combustion exiting from the bed. Another portion of the tubes pass through the bed and extend at an angle to the upper surface of the bed.

Talmud, Fred M. (Berkeley Heights, NJ); Garcia-Mallol, Juan-Antonio (Morristown, NJ)

1980-01-01

214

Radiation effects on heat transfer in heat exchangers, (2)  

International Nuclear Information System (INIS)

In a high temperature gas-cooled reactor system, in which the working fluid exchanges heat at high temperature near 1000 deg C, the heat transfer acceleration by positively utilizing the radiation heat transfer between solid surfaces should be considered. This paper reports on the results of experiment and analysis for the effects of radiant heat on the heat transfer performance at elevated temperature by applying the heat transfer-accelerating method using radiators to the heat exchanger with tube bundle composed of two channels of heating and heated sides. As the test heat exchangers, a parallel counter flow exchanger and the cross flow exchanger simulating helical tubes were employed, and the results studied on the characteristics of each heat exchanger are described. The plates placed in parallel to flow in every space of the tube bundle arranged in a matrix were used as the heat transfer accelerator. The effects of acceleration with the plates were the increase of heat transmission from 12 to 24% and 12 to 38% in the parallel flow and cross flow heat exchangers, respectively. Also, it was clarified that the theoretical analysis, in which it was assumed that the region within pitch S and two radiator plates, with a heat-transferring tube placed at the center, is the minimum domain for calculation, and that the heat exchange by radiation occurs only between the domain and the adjacent domains, can estimate the heat transfer-accelerating effect and the temperature distribution in a heat exchanger with sufficient accuracy. (Wakatsuki, Y.)

1980-01-01

215

SAFE gas turbine cycle primary heat exchangers  

International Nuclear Information System (INIS)

Los Alamos National Laboratory and Marshall Space Flight Center are jointly developing two modular heat pipe heat exchangers, collectively named FIGMENT (Fission Inert Gas Metal Exchanger for Non-nuclear Testing). The FIGMENT heat exchangers are designed to transfer power from the SAFE nuclear reactor cores to gas turbine energy converters. A stainless steel prototype heat exchanger will be built during 2002 in preparation for the construction of a larger refractory metal version. Two promising FIGMENT stainless steel heat exchanger concepts are reviewed here

2002-01-14

216

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 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 o...

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

2012-01-01

217

Heat exchange phenomena and COP evaluation in heat pump systems coupled to single borehole heat exchangers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In recent years a growing interest in Borehole Heat Exchangers (BHEs) has been shown in Europe thanks to the increase of installations in systems connected to Ground Source Heat Pumps (GSHPs) used for heating and cooling needs. Different geometries and technical solutions have been de- veloped in order to improve heat exchange with the ground, accompanied by several descriptive models. Recently, innovative technologies as optical fiber for a new Distributed Thermal Response Test (DTRT) have b...

Casellato, Francesco

2013-01-01

218

Irreversibility analysis of cross flow heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

In this paper, a cross flow plate type heat exchanger, operating with unmixed fluids, was analysed with balanced cross flow. For this aim, a cross flow plate type heat exchanger was developed and manufactured in the laboratory. The heat exchanger was tested with an applicable experimental set up, and temperatures, velocity of the air and the pressure losses occurring in the system were measured so that the effectiveness of the heat exchanger has been determined. The minimum entropy generation number has been taken into consideration with respect to the second law of thermodynamics for the heat exchanger in this analysis. The minimum entropy generation number depends on parameters such as optimum flow path length, dimensionless mass velocity, dimensionless heat transfer area and dimensionless heat transfer volume. The variations between the entropy generation number and these parameters were analysed for the manufactured heat exchanger and introduced with their graphics. (author)

Ogulata, R.T.; Doba, F. [Cukurova University, Adana (Turkey). Dept. of Textile Engineering; Yilmaz, T. [Cukurova University, Adana (Turkey). Dept. of Mechanical Engineering

2000-10-01

219

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

220

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.

Masud Behnia

2005-09-01

 
 
 
 
221

Rational Efficiency of a Heat Exchanger  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The authors propose a new and unique definition for the rational efficiency of a heat exchanger. This new rational efficiency is defined in terms of its sub-rational efficiencies: a heat transfer rational efficiency and a friction rational efficiency for each of the fluid systems comprising the heat exchanger. The heat transfer rational efficiency is based on the definition of a mean temperature for the heat source and a mean temperature for the heat sink and reflects the exergy supplied and ...

2011-01-01

222

Compact heat exchanger for fluids  

International Nuclear Information System (INIS)

The invention concerns a welded heat exchanger with two or more fluids which can be used counter current. The principle of the apparatus allows the use of rolled welded concentric metal strips as well as spiral rolled metal strips. The ring sheets are kept apart either by their rigidity due to the cylindrical shape or by deformations in the sheets themselves or yet again by spacers or chequered and/or perforated sheets forming for instance corrugated spacers, the end sheet being thick enough to take the pressure strain

1975-01-01

223

Heat exchanger thermal insulation system  

International Nuclear Information System (INIS)

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

1974-01-01

224

Optimization of heat exchanger for indirectly heated water heater  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Kaduchová Katarína; Lenhard Richard; Janda?ka Jozef

2012-01-01

225

Modelling of Multistream LNG Heat Exchangers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The main goal of this thesis is to find out if a liquefied natural gas multistream heat exchanger numerical model is achievable. This should include several features usually neglected in nowadays available heat exchanger models, such as flow maldistribution, changes in fluid properties and heat exchanger dynamic behaviour. In order to accomplish that objective a simpler case is modelled. Efforts are put in achieving numerical stability.A counter flow natural gas and mixed refrigerant heat exc...

Soler Fossas, Joan

2011-01-01

226

Thermodynamic Optimization of GSHPS Heat Exchangers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, a new method for determining the optimized dimensions of a ground source heat pump system (GSHPS) heat exchanger is presented. Using the GSHPS is one of the ways for utilization of infinite, clean and renewable energies in the environment. In recent years, due to limitation of physical space for installing the heat exchangers and avoiding the environmental effects on heat exchanger operation, vertical GSHP systems are used more than the other ones. Determination of opt...

Javad Marzbanrad; Ali Sharifzadegan; Ahmad Kahrobaeian

2007-01-01

227

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

228

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

2012-11-01

229

Cooling device for a heat exchange fluid  

International Nuclear Information System (INIS)

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

1975-05-15

230

Direct contact heat exchangers for space  

Science.gov (United States)

Direct contact heat exchanger concepts have been investigated for use in space, including droplet vortex heat exchangers, coflowing droplet heat exchangers, electrostatically driven heat exchangers, and belt and disk heat exchangers. These concepts are characterized by a low heat exchanger mass per unit of heat transferred, low pressure losses, high reliability, and compactness in design. Operation in zero-G poses unique problems for those direct contact heat exchangers which require separation of two fluid media after heat transfer is completed. Other problems include maintenance of good heat transfer coefficients in the absence of buoyant forces, exposure of heat transfer media to vacuum conditions for certain applications, and materials compatibility. A preliminary systems analysis indicates the potential for substantial weight reductions in turbine Brayton cycle space power systems for output powers above several MW(e). Based on the status of current technology and the results of this analysis, recommendations are made for the most attractive applications and the R&D required to ready a direct contact heat exchanger for use in space.

Taussig, R. T.; Thayer, W. J.; Lo, V. C. H.; Sakins, K. M.; Bruckner, A. P.

1985-06-01

231

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

232

Design of single passage heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The available literature has been reviewed, and information useful for heat exchanger design has been presented and compared. The available design information is presented in the form of simplified equations that are suitable for the design of heat exchangers for livestock buildings. The equations presented have been used to develop a computer program as an example of how they can be arranged to aid in designing heat exchangers. 14 refs.

Fehr, R.L.; Walton, L.R.; Parker, B.F.

1981-01-01

233

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

234

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 exch...

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

2013-01-01

235

High temperature heat exchange: nuclear process heat applications  

International Nuclear Information System (INIS)

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

1980-10-03

236

High temperature heat exchange: nuclear process heat applications  

Energy Technology Data Exchange (ETDEWEB)

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

Vrable, D.L.

1980-09-01

237

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

238

Probe Measures Fouling As In Heat Exchangers  

Science.gov (United States)

Combustion deposits reduce transfer of heat. Instrument measures fouling like that on gas side of heat exchanger in direct-fired boiler or heat-recovery system. Heat-flux probe includes tube with embedded meter in outer shell. Combustion gases flow over probe, and fouling accumulates on it, just as fouling would on heat exchanger. Embedded heat-flow meter is sandwich structure in which thin Chromel layers and middle alloy form thermopile. Users determine when fouling approaches unacceptable levels so they schedule cleaning and avoid decreased transfer of heat and increased drop in pressure fouling causes. Avoids cost of premature, unnecessary maintenance.

Marner, Wilbur J.; Macdavid, Kenton S.

1990-01-01

239

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

2012-04-01

240

Heat exchanger network retrofit optimization involving heat transfer enhancement  

International Nuclear Information System (INIS)

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

2012-10-01

 
 
 
 
241

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

242

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

2010-05-01

243

Experimental evaluation of vibrations in heat exchangers  

International Nuclear Information System (INIS)

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

1997-10-27

244

Tube in-shell heat exchanger  

International Nuclear Information System (INIS)

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

1975-08-20

245

Development of high effectiveness droplet heat exchangers  

Science.gov (United States)

An experimental and analytical investigation has been carried out to assess the feasibility of developing high effectiveness, high temperature droplet heat exchangers and to identify practical applications for this type of direct contact heat exchanger. The droplet heat exchanger (DHX) concept studies uses a counterflowing gas and droplet configuration, uniformly sized droplets or particles, and a uniform dispersion of droplets in gas to achieve high heat exchanger effectiveness. Direct contact between the heat transfer media eliminates the solid heat transfer surfaces that are used in conventional heat exchangers and is expected to make very high temperature heat transfer practical. Low temperature simulation tests and analysis have been used to demonstrate that uniformly sized droplets can be generated over a wide range of fluid properties and operating conditions appropriate for high temperature droplet heat exchanger applications. One- and two-dimensional, two-phase flow and heat transfer computer models have been developed and used to characterize both individual component configurations and overall DHX heat transfer rates and effectiveness. The computer model and test data began to diverge as the operating pressure was increased, indicating a need for more general transport rate correlations and a better understanding of the two-phase flows that govern DHX operation.

Thayer, W. J., III; Sekins, K. M.; Bruckner, A. P.

1985-04-01

246

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermal characteristics of multichannel slot-hole heat exchanger with the developed surface of heat exchange inside the opened-cycle water cooling system are experimentally investigated. Graphic dependences of average value of temperature of the simulator of a heat current and temperatures of the heat exchanger base are presented on tapped-off power. Dependences of tapped-off power and hydraulic losses on the of water consumption are given. It is shown, that use of developed slot-hole heat ex...

2010-01-01

247

Exergetic optimisation of a heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

The objective of this paper is to show that for the optimal design of an energy system, where there is a trade-off between exergy saving during operation and exergy use during construction of the energy system, exergy analysis and life cycle analysis should be combined. The two methods are often used separately, but a limited number of studies has been carried out in which they are combined in some way. An exergy optimisation of a heat exchanger has been carried out on the basis of the life cycle analysis method in this paper. The optimisation takes into account irreversibilities due to frictional pressure drop and the temperature difference between the hot and cold stream and irreversibilities due to the production of the materials and the construction of the heat exchanger. As example of this type of heat exchanger a water to water heat exchanger in a city heating system has been selected. The influence of the configuration of the heating system, including the energy conversion, on the optimisation of the heat exchangers has been shown. The analysis of the heat exchanger in which exergy analysis and life cycle analysis are combined gives the design conditions of the heat exchangers which lead to the lowest life cycle irreversibility. 19 refs, 3 figs, 4 tabs

Corneliessen, R.L.; Hirs, G.G. [Twente Univ., Enschede (Netherlands). Dept. of Mechanical Engineering

1996-11-01

248

Heat exchanger for air conditioning system  

Energy Technology Data Exchange (ETDEWEB)

In a heat exchanger for an air conditioning system including a plurality of heat exchanger tubes and a plurality of fins secured to outer surfaces of the heat transfer tubes, the fins are of a special constructional form, such as slitted fins having slits formed in flat or convoluted fins or spine fins, and the heat transfer tubes are each formed on its inner wall surface with spiral grooves or two systems of spiral grooves of large number. The heat transfer tubes define therein a refrigerant passage while the adjacent two fins define therebetween an air passage extending past the outer surfaces of the heat transfer tubes.

Onishi, T.; Horiuchi, M.; Mikata, H.; Nakata, H.; Oshima, S.

1985-10-08

249

Testing and plugging power plant heat exchangers  

International Nuclear Information System (INIS)

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

1994-10-24

250

Heat transfer analysis of short helical borehole heat exchangers  

International Nuclear Information System (INIS)

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

2013-02-01

251

Component Cooling Heat Exchanger Heat Transfer Capability Operability Monitoring  

International Nuclear Information System (INIS)

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

2010-05-16

252

Heat transfer characteristics of a direct contact heat exchanger  

International Nuclear Information System (INIS)

As a first step for development of a direct contact steam generator for FBRs, fundamental heat transfer characteristics of a liquid-liquid contact heat exchanger were evaluated by heat transfer experiment with low melting point alloy and water. Distinctive characteristics of direct contact heat transfer with liquid metal and water was obtained. (author)

1993-05-01

253

Sleeving repair of heat exchanger tubes  

International Nuclear Information System (INIS)

Defective heat exchanger tubes can be repaired using techniques that do not involve the cost and schedule penalties of component replacement. FTI's years of experience repairing steam generator tubes have been successfully applied to heat exchangers. Framatome Technologies heat exchanger sleeves can bridge defective areas of the heat exchanger tubes, sleeves have been designed to repair typical heat exchanger tube defects caused by excessive tube vibration, stress corrosion cracking, pitting or erosion. By installing a sleeve, the majority of the tube's heat transfer and flow capacity is maintained and the need to replace the heat exchanger can be delayed or eliminated. Both performance and reliability are improved. FTI typically installs heat exchanger tube sleeves using either a roll expansion or hydraulic expansion process. While roll expansion of a sleeve can be accomplished very quickly, hydraulic expansion allows sleeves to be installed deep within a tube where a roll expander cannot reach. Benefits of FTI's heat exchanger tube sleeving techniques include: - Sleeves can be positioned any where along the tube length, and for precise positioning of the sleeve eddy current techniques can be employed. - Varying sleeve lengths can be used. - Both the roll and hydraulic expansion processes are rapid and both produce joints that do not require stress relief. - Because of low leak rates and speed of installations, sleeves can be used to preventatively repair likely-to-fail tubes. - Sleeves can be used for tube stiffening and to limit leakage through tube defects. - Because of installation speed, there is minimal impact on outage schedules and budgets. FTI's recently installed heat exchanger sleeving at the Kori-3 Nuclear Power Station in conjunction with Korea Plant Service and Engineering Co., Ltd. The sleeves were installed in the 3A and 3B component cooling water heat exchangers. A total of 859 tubesheet and 68 freespan sleeves were installed in the 3A heat exchanger, and 1020 tubesheet and 244 freespan sleeves were installed in the 3B heat exchanger. Hydraulically expanded sleeves were used in the freespan areas while the tubesheet sleeves were roll expanded. (author)

2000-04-18

254

Sleeving repair of heat exchanger tubes  

Energy Technology Data Exchange (ETDEWEB)

Defective heat exchanger tubes can be repaired using techniques that do not involve the cost and schedule penalties of component replacement. FTI's years of experience repairing steam generator tubes have been successfully applied to heat exchangers. Framatome Technologies heat exchanger sleeves can bridge defective areas of the heat exchanger tubes, sleeves have been designed to repair typical heat exchanger tube defects caused by excessive tube vibration, stress corrosion cracking, pitting or erosion. By installing a sleeve, the majority of the tube's heat transfer and flow capacity is maintained and the need to replace the heat exchanger can be delayed or eliminated. Both performance and reliability are improved. FTI typically installs heat exchanger tube sleeves using either a roll expansion or hydraulic expansion process. While roll expansion of a sleeve can be accomplished very quickly, hydraulic expansion allows sleeves to be installed deep within a tube where a roll expander cannot reach. Benefits of FTI's heat exchanger tube sleeving techniques include: - Sleeves can be positioned any where along the tube length, and for precise positioning of the sleeve eddy current techniques can be employed. - Varying sleeve lengths can be used. - Both the roll and hydraulic expansion processes are rapid and both produce joints that do not require stress relief. - Because of low leak rates and speed of installations, sleeves can be used to preventative repair likely-to-fail tubes. - Sleeves can be used for tube stiffening and to limit leakage through tube defects. - Because of installation speed, there is minimal impact on outage schedules and budgets. FTI's recently installed heat exchanger sleeving at the Kori-3 Nuclear Power Station in conjunction with Korea Plant Service and Engineering Co., Ltd. The sleeves were installed in the 3A and 3B component cooling water heat exchangers. A total of 859 tubesheet and 68 freespan sleeves were installed in the 3A heat exchanger, and 1020 tubesheet and 244 freespan sleeves were installed in the 3B heat exchanger. Hydraulically expanded sleeves were used in the freespan areas while the tubesheet sleeves were roll expanded. (author)

Street, Michael D.; Schafer, Bruce W. [Framatome Technologies, Inc. Virginia (United States)

2000-07-01

255

Performances of heat exchangers on HTGR application  

International Nuclear Information System (INIS)

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

1980-01-01

256

Optimum design of double pipe heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

Heat exchangers are used in industrial processes to recover heat between two process fluids. Although the necessary equations for heat transfer and the pressure drop in a double pipe heat exchanger are available, using these equations the optimization of the system cost is laborious. In this paper the optimal design of the exchanger has been formulated as a geometric programming with a single degree of difficulty. The solution of the problem yields the optimum values of inner pipe diameter, outer pipe diameter and utility flow rate to be used for a double pipe heat exchanger of a given length, when a specified flow rate of process stream is to be treated for a given inlet to outlet temperature. (author)

Swamee, Prabhata K. [Department of Civil Engineering, Indian Institute of Technology, Roorkee, Roorkee 247 667 (India); Aggarwal, Nitin [Department of Chemical Engineering, New Jersey Institute of Technology, NJ 07032 (United States); Aggarwal, Vijay [UOP, Unitech Trade Center, Sector 43, Block C, Sushant Lok Phase-1, Gurgaon, 122 001 Haryana (India)

2008-05-15

257

Heat exchanger and its manufacturing method  

International Nuclear Information System (INIS)

A plurality of helical type double-walled heat transfer tubes are disposed in an outer cylinder. Each of the helical type double-walled heat exchange tubes has an outer tube in a state where a gap is formed at the outer circumference of an inner tube. A porous metal is disposed in the gap between the inner tube and the outer tube. A leakage detection means is disposed for detecting leakage of fluid circulating in the heat exchange tubes by way of the gap between the inner and the outer tubes. The helical type double-walled heat transfer tube is formed by cold helical fabrication, and then heat treatment is applied in an argon gas atmosphere. Since a helical type double-walled heat transfer tube is used, a great heat transfer area per unit volume can be provided. Accordingly, the capacity of the heat exchanger can be increased without enlarging the size of the heat exchanger and increasing the number of the heat transfer tubes. In addition, since heat treatment is applied, the close bondability between the inner or the outer tube and the porous metal is restored, thereby enabling to make heat transfer performance satisfactory. (I.N.)

1993-05-18

258

Heat exchangers for HHT nuclear power plants  

International Nuclear Information System (INIS)

Closed gas turbine installations are equipped with recuperator, precooler and, depending on the design concept, an 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 HT reference plant (high-temperature reactor with helium turbine)

1979-01-01

259

Thermodynamic Optimization of GSHPS Heat Exchangers  

Directory of Open Access Journals (Sweden)

Full Text Available

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

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

Ahmad Kahrobaeian

2007-09-01

260

The explosive plugging of heat exchangers  

International Nuclear Information System (INIS)

The mechanism and development of explosive welding and particularly the application to tube to tubeplate welding is briefly reviewed. The need for plugging of heat exchangers in the power generating industry and the requirement for producing a high integrity weld are discussed. Details are given of the explosive plugging system developed for the reheater heat exchanger of the prototype fast reactor (PFR), including data on weld lengths and distortion of adjoining holes. Results of destructive and non-destructive tests on trial plugging of a seven hole array are given. The system described has been successfully applied to an actual heat exchanger and the procedure followed is briefly discussed. (author)

1972-09-17

 
 
 
 
261

The explosive plugging of heat exchangers  

International Nuclear Information System (INIS)

The paper briefly reviews the mechanism and development of explosive welding and particularly the application to tube to tubeplate welding. The need for plugging of heat exchangers in the power generating industry and the requirement for producing a high integrity weld are discussed. Details are given of the explosive plugging system developed for the reheater heat exchanger of the prototype fast reactor (PFR), including data on weld lengths and distortion of adjoining holes. Results of destructive and non-destructive tests on trial plugging of a seven hole array are given. The system described has been successfully applied to an actual heat exchanger and the procedure followed is briefly discussed. (author)

1972-09-21

262

Heat Exchanger Support Bracket Design Calculations  

International Nuclear Information System (INIS)

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.

1995-01-01

263

Improvements to heat exchangers with U tubes  

International Nuclear Information System (INIS)

The aim of this invention is to build an improved heat exchanger with return bend tubes. Under the invention, a tube with a return bend is provided that defines the flow path of a running fluid in heat exchange relation with another fluid taking a path on which the return bend tube is placed, so that one of the branches of the return bend tube has a greater temperature than the other. The tube is fitted and supported so that the stresses of its return bend are no greater than they would be were the heat exchanger entirely at ambient temperature

1976-08-06

264

14 CFR 23.1125 - Exhaust heat exchangers.  

Science.gov (United States)

...2010-01-01 false Exhaust heat exchangers. 23.1125 Section 23...System § 23.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

2010-01-01

265

14 CFR 29.1125 - Exhaust heat exchangers.  

Science.gov (United States)

...2010-01-01 false Exhaust heat exchangers. 29.1125 Section 29...System § 29.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

2010-01-01

266

14 CFR 25.1125 - Exhaust heat exchangers.  

Science.gov (United States)

...2010-01-01 false Exhaust heat exchangers. 25.1125 Section 25...System § 25.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

2010-01-01

267

Increasing the Efficiency of Maple Sap Evaporators with Heat Exchangers.  

Science.gov (United States)

A study of the engineering and economic effects of heat exchangers in conventional maple syrup evaporators indicated that: (1) Efficiency was increased by 15 to 17 percent with heat exchangers; (2) Syrup produced in evaporators with heat exchangers was si...

L. D. Garrett H. Duchacek M. Morselli F. M. Laing N. K. Huyler

1977-01-01

268

Heat exchanger with transpired, highly porous fins  

Science.gov (United States)

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

269

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 effe...

Denkenberger, David C.; Brandemuehl, Michael J.; Pearce, Joshua M.; Zhai, John

2012-01-01

270

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

2012-04-01

271

High Efficiency Flat Panel Microchannel Heat Exchanger.  

Science.gov (United States)

An apparatus providing high efficiency heat exchange between two fluids is disclosed. The apparatus most commonly comprises a flat panel with microchannels directing the flow of the two fluids, specifically: with a small hydraulic diameter in order to inc...

K. W. Kelly A. McCandless

2005-01-01

272

Heat exchanger development in the 1980s  

International Nuclear Information System (INIS)

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

273

A heat exchanger with dual tubes  

International Nuclear Information System (INIS)

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

1973-08-21

274

Fireplace heat exchanger apparatus and method  

Energy Technology Data Exchange (ETDEWEB)

A fireplace heat exchanger apparatus and method utilizes a tubular grate for holding fuel to be burned having a bottom portion for collecting a liquid such that the liquid will be vaporized by the heat from the fuel burned in the grate and carried into a space to be heated by air forced through the tubular grate to substantially increase the amount of heat obtained from burning of fuel.

Faustini, C.

1983-05-03

275

Heat exchanger condition and remaining life assessment  

Energy Technology Data Exchange (ETDEWEB)

EPRI GS-6724 is a guideline which, in part, outlines a phased approach for performing power plant heat exchanger condition assessments. Remaining life projections that result from these assessments enable utilities to accurately and cost effectively extend component and system life. Overview and in-depth descriptions of essential procedural information from the EPRI guideline -- as applicable to power plant heat exchangers, recommended remaining life assessment methods and case histories -- are provided.

Bell, R.J.; Conley, E.F. [Heat Exchanger Systems, Inc., Boston, MA (United States)

1995-08-01

276

Corrosion testing of heat exchanger tubing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Heat exchanger tubes are commonly made from stainless steel.In a heat exchanger both the process fluid and the cooling orheating media can be corrosive. It is therefore important to beable to select materials that do not suffer from corrosion.Current methods in this area, however, suffer from limitationsand shortcomings. This thesis concerns corrosion tests forgeneral corrosion, dewpoint corrosion and stress corrosioncracking, respectively. For evaluation of general corrosion ofsuperduplex st...

2003-01-01

277

Stirling Engine With Radial Flow Heat Exchangers  

Science.gov (United States)

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

Vitale, N.; Yarr, George

1993-01-01

278

Straight tube heat exchanger for hot gases  

International Nuclear Information System (INIS)

The hot helium gas entering the heat exchanger flows through several units with the gas pipes being arranged in crosscounter flow. The second cold gas entering surrounds these units in a duct, which is in turn surrounded by a duct, in which the cooled helium gas flows back. Entry and outlet of both gases are situated at the same end of the heat exchanger, so that it can expand freely from one end to the other. (GL)

1979-01-01

279

Tube-in-shell heat exchangers  

International Nuclear Information System (INIS)

A tube-in-shell heat exchanger is described for use in liquid metal cooled fast breeder reactor constructions. The system consists of a bundle of heat exchange tubes with a central spine extending longitudinally through the shell and a series of longitudinally spaced transverse grids resiliently mounted on the central spine within the shell to provide transverse support for bracing the tubes apart. (U.K.)

1980-01-01

280

Indirect heat exchanger system with parallel exchange loops  

International Nuclear Information System (INIS)

The indirect heat exchanger system under the invention is characterized in that the exchange loops are at different levels and are alternately staggered, the odd line loops being in a first position and the even line loops being in a second position deduced from the first by a translation, so that the collectors, expansion vases, pump and separator of each loop are not facing the corresponding components of an adjacent loop

1982-01-01

 
 
 
 
281

Method for removing coronene from heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

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.

Kmak, W.

1980-07-29

282

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

283

Mathematical Modeling of Spiral Heat Exchanger  

Directory of Open Access Journals (Sweden)

Full Text Available Compact Heat Exchangers (CHEs are increasingly being used on small and medium scale industries. Due to their compact size and efficient design, they facilitate more efficient heat transfer. Better heat transfer would imply lesser fuel consumption for the operations of the plant, giving improvement to overall efficiency. This reduction in consumption of fuel is a step towards sustainable development. This report exclusively deals with the study the spiral heat exchanger.The design considerations for spiral heat exchanger is that the flow within the spiral has been assumed as flow through a duct and by using Shah London empirical equation for Nusselt number design parameters are further optimized.This is accompanied by a detailed energy balance to generate a concise mathematical model

Probal Guha , Vaishnavi Unde

2014-04-01

284

Ceramic heat exchangers: manufacturing techniques and performance  

Energy Technology Data Exchange (ETDEWEB)

The objective of the ceramic heat pipe program being conducted at Los Alamos is demonstration of the practical feasibility of this technology for the solution of severe high temperature recuperation functions. Ceramic heat pipe recuperators have been theoretically shown to offer distinct advantages over conventional ceramic heat exchangers from the standpoint of efficiency of heat recuperation and economics. The main stumbling block to their widespread utilization is related to the problems of materials for construction and the details of fabrication and assembly. The performance objectives of ceramic heat pipes and some aspects of the materials technology program aimed at solving the problem of economic ceramic heat pipe fabrication are described.

Merrigan, M.A.; Sandstrom, D.J.

1981-01-01

285

Heat exchanger for high temperatures and pressures  

International Nuclear Information System (INIS)

This invention refers to a heat exchanger for high temperatures and pressures. Specifically, the invention concerns a high temperature and high pressure heat exchanger of the type comprising, within a leaktight containment, a plurality of tubes around which flows a primary fluid and through which flows a secondary fluid, and at least one plate delimitating an outlet chamber for the secondary fluid at one of the ends of the containment. This exchanger prevents the establishment of excessive thermal gradients in the wall of this chamber, when rapid changes in the temperature of this secondary fluid occur

1977-01-01

286

Nonstationary heat exchange in channels  

International Nuclear Information System (INIS)

Results are reported for investigations of nonstationary processes of heat transfer to a single-phase heat-transport medium in tube-type channels in the presence of various types of disturbances. Two characteristic stages are distinguished for processes with aperiodic variation in flow rate: in the first, both the flow rate and heat flux vary and in the second, only the heat flux changes. A formula for calculating the reduced coefficient of nonstationary heat transfer has been obtained on the basis of experiments carried out with constant flow rate and variable heat flux and experiments with the flow rate changing in accordance with different laws. The universality of the formula has been confirmed by a series of experiments in which the transport-medium flow rate and the channel thermal power were varied simultaneously. 12 refs

1981-01-01

287

PENGARUH TEBAL ISOLASI TERMAL TERHADAP EFEKTIVITAS PLATE HEAT EXCHANGER  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2000-01-01

288

Integrated heat exchangers for a nuclear reactor  

International Nuclear Information System (INIS)

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

1982-01-01

289

Heat transfer from oriented heat exchange areas  

Directory of Open Access Journals (Sweden)

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

Vantuch Martin

2014-03-01

290

Heat transfer from oriented heat exchange areas  

Science.gov (United States)

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

Vantuch, Martin; Huzvar, Jozef; Kapjor, Andrej

2014-03-01

291

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

292

Secondary effects in spiral heat exchangers  

International Nuclear Information System (INIS)

The results of an experimental investigation of inductrial cryogenic spiral tube-fin heat exchangers (HE) and the analysis of the influence of various secondary effects on the HE efficiency are given. Data on longitudinal heat conductivity of the spiral tube-fin HE structure is presented. 14 refs.; 9 figs.; 5 tabs

1989-01-01

293

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

294

Phase Change Material Heat Exchanger Life Test  

Science.gov (United States)

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

Lillibridge, Sean; Stephan, Ryan

2009-01-01

295

Counter flow heat exchanger between two fluids  

International Nuclear Information System (INIS)

This invention concerns a counter flow heat exchanger between a primary fluid which cools down inside tubes having the general shape of an inverted J, or in any other self expanding form, a tube bundle and a secondary fluid which heats up around this tube bundle. The latter extends between a tube plate of a central area and an annular tube plate of a peripheral area. The invention described relates in particular to a steam generator in which the secondary water is heated and vaporized, and possibly superheated, by counter flow exchange with the primary fluid

1981-01-01

296

Heat Exchanger With Internal Pin Elements  

Science.gov (United States)

A heat exchanger/heater comprising a tubular member having a fluid inlet end, a fluid outlet end and plurality of pins secured to the interior wall of the tube. Various embodiments additionally comprise a blocking member disposed concentrically inside the pins, such as a core plug or a baffle array. Also disclosed is a vapor generator employing an internally pinned tube, and a fluid-heater/heat-exchanger utilizing an outer jacket tube and fluid-side baffle elements, as well as methods for heating a fluid using an internally pinned tube.

Gerstmann, Joseph (Framingham, MA); Hannon, Charles L. (Arlington, MA)

2004-01-13

297

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.

2010-02-01

298

Heat transfer characteristics of a helical heat exchanger  

International Nuclear Information System (INIS)

Heat transfer performance of a helical heat exchanger was investigated. The heat exchanger is composed of a helical tube with rectangular cross section and two cover plates. The ?–Ntu relation of the heat exchanger was obtained using a numerical method. In the analysis, the flow in the tube (helical flow) was considered to be mixed and the flow outside the tube (radial flow) was unmixed. In the experiment, the Darcy friction factor (f) and convective heat transfer coefficient (h) of the radial flow were measured. The radial flow was air and the helical flow was water. Four different channel spacing (0.5, 0.8, 1.2 and 1.6 mm) were individually considered. The Reynolds numbers were in the range 307–2547. Two correlations, one for the Darcy friction factor and the other for the Nusselt number, were proposed. - Highlights: ? We analyze the heat transfer characteristics of a helical heat exchanger and examine the effectiveness–Ntu relation. ? Increasing number of turns of the heat exchanger would slightly increase the effectiveness. ? There is an optimum Ntu value corresponding to a maximum effectiveness. ? We measure the Darcy friction factor and Nusselt number of the radial flow and examine the correlations.

2012-06-01

299

Improvements in or relating to heat exchangers  

International Nuclear Information System (INIS)

A heat exchanger is described that is suitable for use with high temperature gas cooled reactors in which the heat is used as process heat. The construction which is of necessity of large size, is of much lighter weight than current constructions and is better able to withstand the high operating temperature (up to about 10000C). Carbon fibre reinforced carbon materials are employed as constructional materials. A method of fabrication is described. The heat exchanger comprises a tube or bundle of tubes associated with a header plate, and the tube can be of helical form. The carbon materials may be formed by carbonisation of a thermosetting plastic such as a phenolic resin. The exchanger is rendered substantially impermeable to gas by an infiltration treatment of the carbon material using a cracked hydrocarbon gas. (U.K.)

1978-01-01

300

Simultaneous synthesis of flexible heat exchanger networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In industry there is still lot of potential to make an energy system more efficient and thereby reduce the waste heat available. On the other hand there is an option to export the waste heat to another industry or to society. When the use of a heat exchanger network is considered for these tasks the optimization framework developed in this work can be implemented to calculate the cost of optimal investments.

2003-01-01

 
 
 
 
301

Heat exchanger with auxiliary cooling system  

International Nuclear Information System (INIS)

A heat exchanger with an auxiliary cooling system is described which is 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

1980-01-01

302

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

303

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

304

Comparison between conventional heat exchanger performance and an heat pipes exchanger  

International Nuclear Information System (INIS)

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

1989-12-05

305

RECITAL SCRUTINY ON TUBE-INTUBE COMPACT HEAT EXCHANGERS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 8...

2011-01-01

306

A heat exchanger provided with plates  

International Nuclear Information System (INIS)

The invention relates to a heat exchanger of the plate type, in which two fluids exchange calories through parallel metal plates, delimiting spaces separated from each other in which two fluids respectively flow without direct contact between them. The invention particularly applies in the case where one of the two fluids is water under pressure or else a circulating liquid metal, specially sodium, used in the system of a pressurised water or fast neutron reactor, the second fluid being water to be vaporised in the exchanger by the calories supplied by the first fluid. The arrangement is designed to give minimum bulk, particularly enabling the exchanger to be housed in the area between the core of a nuclear reactor and a casing or outer vessel, or else in an external sealed containment, with a view to recovering with the best efficiency the heat acquired by a coolant flowing through the core

1976-01-01

307

Failure analysis of a heat exchanger  

International Nuclear Information System (INIS)

The rupture of a heat exchanger inside an inert atmosphere glovebox threatened to damage a radioactively fueled heat source intended to generate electricity on a future US space flight. Because of the potential for damage to heat sources in other gloveboxes, it was necessary to identify the cause of failure. The failure analysis was effected by listing possible causes of rupture and then determining which possibilities were consistent with evidence obtained from the failed heat exchanger. Macroscopic evaluation of the heat exchanger provided information as to the nature of the failure. Scanning electron microscopy and energy dispersive x-ray analysis were used to confirm the failure mechanism. Metallographic sections of both ruptured and deformed tubes gave clues as to the history of the material, as did microhardness measurements. Tensile tests on undeformed tubing provided estimates of strength. Burst tests on similar tubing were used to confirm the validity of the tensile data. Finally, the tensile data were used in models to determine which of the proposed scenarios of failure were most likely. It was concluded that failure had occurred because, periodically during the life of the heat exchanger, both the inlet and outlet valves had deliberately been closed. The subsequent rise in temperature caused expansion of the coolant, and a corresponding rise in hydrostatic pressure occurred which was sufficient to deform the tubing upon each repetition

1985-11-17

308

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

2007-05-01

309

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

310

Heat exchanger for coal gasification process  

Science.gov (United States)

This invention provides a heat exchanger, particularly useful for systems requiring cooling of hot particulate solids, such as the separated fines from the product gas of a carbonaceous material gasification system. The invention allows effective cooling of a hot particulate in a particle stream (made up of hot particulate and a gas), using gravity as the motive source of the hot particulate. In a preferred form, the invention substitutes a tube structure for the single wall tube of a heat exchanger. The tube structure comprises a tube with a core disposed within, forming a cavity between the tube and the core, and vanes in the cavity which form a flow path through which the hot particulate falls. The outside of the tube is in contact with the cooling fluid of the heat exchanger.

Blasiole, George A. (Greensburg, PA)

1984-06-19

311

The dynamic behaviour of heat exchangers  

International Nuclear Information System (INIS)

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

1963-01-01

312

Compact gas-gas heat exchanger IFP  

Energy Technology Data Exchange (ETDEWEB)

The European market study carried out by IFP and Creusot-Loire in the present framework has shown that a 2 millions toe/year savings can be expected from new gas-gas heat recovery systems in the present industrial context. The main constraint to be overcome is the cost of setting up in industrial plants. The compactness and modular conception of the new stacked perforated plates (SPP) gas-gas heat exchanger will undoubtedly help in getting this new equipment on to the market. The exchanger consists of a block formed by the stacking of judiciously superpositioned perforated metal plates whose apertures create the fluid flow passages. This compact gas-gas cross flow heat exchanger is easy to manufacture, with low pressure drops and easy to clean fume passages. The different plates perforations geometries, tested in laboratories on small models (exchange area: 0.35 mS) showed the possibility of attaining specific areas of 125 mS/mT and heat transfer coefficients up to 70 W/mS/K. The data obtained from these tests serve as a basis for planning industrial devices and have been used to design a prototype (exchange area: 12.5 mS) which includes cleaning devices. The tests of this prototype carried out on a 1.6 MW boiler with fume flow-rates in range of a 2000 mT/h and outlet temperatures up to 400C showed a good agreement with the laboratory tests and demonstrated that specific heat transfer in excess of 5 kW/mT.C should be achievable, an order of magnitude better than tubular radiator-type units. A comparison of the expected cost price of the SPP unit with a number of other heat exchangers indicates that the SPP unit could be very competitive on the market for energy saving devices.

Grehier, A.; Raimbault, C.; Rojey, A.; Busson, C.; Chlique, B.; Dreuilhe, J.

1984-01-01

313

MICROMACHINED HEAT EXCHANGER FOR A CRYOSURGICAL PROBE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes a lithography-based microfabrication process developed for a recuperative heat exchanger intended for use in a cryosurgical probe. The probe, which uses the Joule-Thomson (JT) cooling cycle, must achieve a temperature < -50°C, with a freeze rate of 25-50°C/min. The heat exchanger must maintain high stream-to-stream thermal conductance while restricting parasitic stream-wise (axial) conduction losses. It has a footprint of 6x1.5cm2 and 2.5mm thickness, and is fabricated ...

2005-01-01

314

Analytical study of heat exchanger design  

Energy Technology Data Exchange (ETDEWEB)

Analytical expressions for the temperature distributions for cold as well as hot fluids for a counterflow, tube-in-tube heat exchanger have been derived in terms of known design variables, like the properties of the material of the tube, geometrical configurations, inlet temperatures etc., by applying initial boundary conditions. The effects of change in configuration of flow on temperature distribution have been discussed in detail. Expressions for efficiency of the heat exchanger have also been derived, based on known design parameters for various special cases. (author).

Prabhakant; Tiwari, G.N. (Indian Inst. of Tech., New Delhi (India). Centre of Energy Studies)

1991-01-01

315

Fluid circulation system for heat exchangers  

International Nuclear Information System (INIS)

A fluid circulation system for heat exchangers has two groups of tubes through which primary and secondary fluids flow, the tubes of one group being interdigitated with the tubes of the other group, and a heat transfer material interposed between the two groups of tubes, whereby heat is transferred from the primary fluid through the heat transfer material to the secondary fluid. A shell forms a closure around the tubes and the heat transfer material, and the shell has tertiary fluid inlet and outlet means. Openings in the heat transfer material form passageways through which the tertiary fluid can flow from the inlet means, through the heat exchanger, to the outlet means. Piping connects the tertiary fluid outlet means to the tertiary fluid inlet means , forming a complete cycle. Installed in this piping is a heat removal system. If the secondary fluid flow is interrupted, the tertiary fluid provides a redundant means by which the heat of the primary fluid can be removed from the heat exchanger. Monitoring means can be inserted into the piping, to detect any leakages which may occur in the primary and secondary tubes. Condensers or desiccating material can be installed in the heat removal means to remove any liquids which may leak into the tertiary fluid. Additionally, if the tertiary fluid is a gas or vapor, a turbine can be inserted into the piping and the tertiary fluid's power utilized to provide energy to power the compressor or pump which is circulating the tertiary fluid. In an emergency, this turbine can be connected to an electrical generator and provide emergency power to the rest of the plant

1982-01-01

316

Compact gas-gas heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

The European market study carried out by IFP and Creusot-Loire in the present framework has shown that a 2 million tOE/yr saving can be expected from new gas-gas heat recovery systems in the present industrial context. The main constraint to be overcome is the cost of setting them up in industrial plants. The compactness and modular conception of the new stacked perforated plates (SPP) gas-gas heat exchanger will undoubtedly help in getting this new equipment onto the market. The exchanger consists of a block formed by the stacking of judiciously superpositioned perforated metal plates whose apertures create the fluid flow passages. This compact gas-gas crossflow heat exchanger is easy to manufacture, with low pressure drops and easy-to-clean fumes passages. A comparison of the projected cost of the SPP unit with a number of other heat exchangers indicates that the SPP unit is superior in terms of mass, size and cost and therefore will be very competitive in the market for heat recovery systems.

Grehier, A.; Busson, C.; Chliques, B.; Dreuihles, J.; Raimbault, C.; Rojey, A.

1984-01-01

317

Heat exchanger design for desalination plants  

Energy Technology Data Exchange (ETDEWEB)

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.

1979-03-01

318

Heat exchanger design for desalination plants  

International Nuclear Information System (INIS)

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

319

Online performance assessment of heat exchanger using artificial neural networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 performan...

C Ahilan, S. Kumanan

2011-01-01

320

Heat exchanger containing a component capable of discontinuous movement  

Science.gov (United States)

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

 
 
 
 
321

Micro-Scale Regenerative Heat Exchanger  

Science.gov (United States)

A micro-scale regenerative heat exchanger has been designed, optimized and fabricated for use in a micro-Stirling device. Novel design and fabrication techniques enabled the minimization of axial heat conduction losses and pressure drop, while maximizing thermal regenerative performance. The fabricated prototype is comprised of ten separate assembled layers of alternating metal-dielectric composite. Each layer is offset to minimize conduction losses and maximize heat transfer by boundary layer disruption. A grating pattern of 100 micron square non-contiguous flow passages were formed with a nominal 20 micron wall thickness, and an overall assembled ten-layer thickness of 900 microns. Application of the micro heat exchanger is envisioned in the areas of micro-refrigerators/coolers, micropower devices, and micro-fluidic devices.

Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

2004-01-01

322

Modelling Heat Exchangers for Domestic Boilers  

Directory of Open Access Journals (Sweden)

Full Text Available In the present paper the thermal behaviour of fin-tube heat exchangers is modeled. Particular attention has been given to the plate fins. The heat fluxes in the fins are described using a finite volume technique to discretize the energy equation. The thermal interactions with the water in the tubes and the surrounding air are treated as external boundaries, using appropriate relationships for forced convection in pipes and flat plates. The numerical results are presented in terms of dimensionless numbers (Fourier, Biot and geometric ratios which are found to be representative for this particular geometry. Furthermore, the effect of thermal gradients along the fin surface upon the fin efficiency is investigated. Based on a differential model for the heat balances, design charts have been developed for the thermal analysis of heat exchangers.

S. F. C. F. Teixeira

2000-01-01

323

Hierarchic modeling of heat exchanger thermal hydraulics  

International Nuclear Information System (INIS)

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

2002-09-09

324

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

325

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

326

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

International Nuclear Information System (INIS)

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

1978-01-01

327

Heat exchanger for a contaminated fluid  

International Nuclear Information System (INIS)

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

1994-11-25

328

Measurement of heat and moisture exchanger efficiency.  

Science.gov (United States)

Deciding between a passive heat and moisture exchanger or active humidification depends upon the level of humidification that either will deliver. Published international standards dictate that active humidifiers should deliver a minimum humidity of 33 mg.l(-1); however, no such requirement exists, for heat and moisture exchangers. Anaesthetists instead have to rely on information provided by manufacturers, which may not allow comparison of different devices and their clinical effectiveness. I suggest that measurement of humidification efficiency, being the percentage moisture returned and determined by measuring the temperature of the respired gases, should be mandated, and report a modification of the standard method that will allow this to be easily measured. In this study, different types of heat and moisture exchangers for adults, children and patients with a tracheostomy were tested. Adult and paediatric models lost between 6.5 mg.l(-1) and 8.5 mg.l(-1) moisture (corresponding to an efficiency of around 80%); however, the models designed for patients with a tracheostomy lost between 16 mg.l(-1) and 18 mg.l(-1) (60% efficiency). I propose that all heat and moisture exchangers should be tested in this manner and percentage efficiency reported to allow an informed choice between different types and models. PMID:24047355

Chandler, M

2013-09-01

329

Fretting Wear of Heat Exchanger Tubes.  

Science.gov (United States)

The results of a series of measurements made on the fretting wear of heat exchanger tubes and support plates at room temperature in a nitrogen/air atmosphere are presented. The fretting wear is shown to be a function of the amplitude and frequency of tube...

R. D. Blevins

1978-01-01

330

Tube-in-shell heat exchangers  

International Nuclear Information System (INIS)

A method is described for repairing a defective tube weld in a heat exchanger. A sleeve is inserted within the tube to bridge the defect, one end of the sleeve being brazed to the tube and the other end bonded to the tube sheet by explosive welding. (author)

1980-01-01

331

Qualification of aluminum for OTEC heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The basis for qualification of aluminum as a material for use as tubing in Ocean Thermal Energy Conversion heat exchangers is reviewed. Reference is made to compendia of data from tests of aluminum alloys in natural sea water and to applicable service records. Data from these sources were found to be inadequate to either qualify or disqualify aluminum. They serve only to identify the 5052 alloy and Alclad 3003 or 3004 as being worthy of additional testing under conditions more directly related to what will be encountered in OTEC heat exchangers. The principal deficiency of data from long-time tests in natural sea water is that in almost all of these tests the specimens were exposed under static conditions that caused the surfaces to be covered by marine fouling organisms that would not be present in heat exchanger tubes. The tests did not take into account possible effects of periodic mechanical or chemical treatments to remove fouling or chemical treatments (chlorination) to prevent fouling. A current testing program sponsored by the Department of Energy through Argonne National Laboratory is designed to provide the needed data. Limited tests in high velocity sea water have indicated that aluminum tubes would tolerate the velocities under 10 ft (3 m) per second likely to be used in OTEC heat exchangers.

LaQue, F.L.

1979-05-01

332

Heat exchanger, specifically a steam generator heated with liquid sodium  

International Nuclear Information System (INIS)

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

1976-01-01

333

Open heat exchanger for improved heat efficiency in geothermal spas  

Energy Technology Data Exchange (ETDEWEB)

Hot spas and Jacuzzis are popular in Iceland due to the abundance of reasonably prized geothermal heat available. However the water from the district heating system is too warm to be admitted directly into the spa. For safety reasons the water is mixed with cold water, in order to reduce temperature from about 80 deg C down to 45 deg C, which leads to wasting a large quantity of heat. Therefore a design is suggested here that enables the feeding of geothermal water directly into the spa, omitting the step of mixing it with cold water. The idea is to employ an open heat exchanger that transfers heat from the geothermal water to the bulk water in the spa, before letting it mix with the spa water. A case study was done for one particular spa. Heat load was calculated and measured when the spa was in use, and when it was unused. A design is suggested employing a circular double-plate which is to be placed at the bottom of the spa. This unit will function as an open heat exchanger feeding district heating water into the spa. Free convection takes place at the upper side of the upper plate and forced convection below the upper plate. Heat transfer coefficient for both was calculated. Using results from calculations, temperature distribution at critical parts of spa and plate was modeled. Results are reasonable and promising for a good design that may considerably reduce the energy expenses for a continuously heated geothermal spa

Nasrabady, S.J.; Palsson, H.; Saevarsdottir, G.A.

2008-09-15

334

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 were mainly used as pasteurizers (e.g. for milk and beer). Industrial plate heat exchangers were introduced in the 1950’s and initially they were converted dairy models. Brazed plate heat exch...

Fernandes, Carla S.; Dias, Ricardo P.; Maia, Joa?o M.

2008-01-01

335

Materials development for HTGR heat exchangers  

International Nuclear Information System (INIS)

Some versions of the HTGR generate high 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

1982-10-21

336

Brayton heat exchange unit development program  

Science.gov (United States)

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

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

1971-01-01

337

Heat Transfer Characteristics of a Three-Phase Volume Boiling Direct Contact Heat Exchanger.  

Science.gov (United States)

The advantages of direct contact heat transfer over heat transfer utilizing conventional metallic heat exchangers are listed. The performance characteristics of a three-phase direct contact heat exchanger in near counterflow operation were evaluated using...

C. K. Blair R. F. Boehm H. R. Jacobs

1976-01-01

338

Stokes flow heat transfer in an annular, rotating heat exchanger  

International Nuclear Information System (INIS)

The heat transfer rate into highly viscous, low thermal-conductivity fluids can be enhanced significantly by chaotic advection in three-dimensional flows dominated by viscous forces. The physical effect of chaotic advection is to render the cross-sectional temperature field uniform, thus increasing both the wall temperature gradient and the heat flux into the fluid. A method of analysis for one such flow-the flow in the eccentric, annular, rotating heat exchanger-and a procedure to determine the best heat transfer conditions, namely the optimal values of the eccentricity ratio and time-periodic rotating protocol, are discussed. It is shown that in continuous flows, such as the one under consideration, there exists an optimum frequency of the rotation protocol for which the heat transfer rate is a maximum. - Highlights: ? The eccentric, annular, rotating heat exchanger is studied for periodic Stokes flow. ? Counter-rotating the inner tube with a periodic velocity enhances the heat transfer. ? The heat-transfer enhancement under such conditions is due to chaotic advection. ? For a given axial flow rate there is a frequency that maximizes the heat transfer. ? There is also an optimum value of the eccentricity ratio.

2011-06-01

339

Some performance characteristics of a fluidized bed heat recovery unit  

International Nuclear Information System (INIS)

The advantages of using fluidized bed heat recovery units with diesel engines are well documented. Two of those are: significantly less tube fouling and heat transfer coefficient four to five time higher than that of conventional shell and tube heat exchangers. The high concentration of soot in the exhaust gases of diesel engines make fouling a major concern in design of any kind of heat recovery unit. In the experiment a conventional fluidized bed heat exchanger was connected to the exhaust of a diesel engine mounted on a dynamometer. With this arrangement it was possible to test the heat recovery unit under a wide range of operating conditions. The main objective of this experiment was the determination of the performance characteristics of the heat recovery unit, especially with reference to its heat transfer and fouling characteristics. (author)

1985-06-02

340

Heat-exchanger, especially intermediate heat exchanger for gas-cooled, high temperature reactors  

International Nuclear Information System (INIS)

Heat exchanger for high temperature gas cooled reactors with one or more exchange units, but with common supply and drain of secondary coolant. Special construction for easy leak testing and repairing of welded joints of one unit during continued operation of the reactor. Also special design of fittings, excess pressure-valves and explosion-protections. (J.K.)

1977-01-01

 
 
 
 
341

AUTOMATIC EVOLUTION OF HEAT EXCHANGER NETWORKS WITH SIMULTANEOUS HEAT EXCHANGER DESIGN  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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, pr...

Liporace, F. S.; Pessoa, F. L. P.; Queiroz, E. M.

1999-01-01

342

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

343

Heat exchanger with auxiliary cooling system  

International Nuclear Information System (INIS)

The auxiliary cooling systems of nuclear reactors have a resistance to the fluid flow although they are not normally in operation and presumably may never be used. This is why the main object of the invention is to produce a heat exchanger with a simple and reliable auxiliary cooling mechanism capable of cooling the reactor without hindering the coolant flow during normal working. The exchanger includes a vertical casing, heat transfer tubes mounted in this casing, inlets and outlets for the secondary coolant to conduct it through the heat transfer tubes and inlets and outlets to conduct the primary coolant through a primary coolant space placed peripherally inside the casing and in heat transfer position with the heat transfer tubes. An auxiliary cooling system is located in an annular chamber around the heat transfer tubes. This annular chamber communicates by the top and by the bottom with the primary coolant space to cool this primary coolant, when it is not flowing, and this gives rise to natural circulation of the primary coolant downwards through this annular chamber

1976-12-16

344

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

345

Preliminary SP-100/Stirling heat exchanger designs  

International Nuclear Information System (INIS)

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

1994-01-09

346

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,

2011-04-01

347

Multi-Purpose Logistics Module (MPLM) Cargo Heat Exchanger  

Science.gov (United States)

This paper describes the New Shuttle Orbiter's Multi- Purpose Logistics Modulo (MPLM) Cargo Heat Exchanger (HX) and associated MPLM cooling system. This paper presents Heat Exchanger (HX) design and performance characteristics of the system.

Zampiceni, John J.; Harper, Lon T.

2002-01-01

348

Rotorua field experiment; Downhole heat exchanger performance  

Energy Technology Data Exchange (ETDEWEB)

Rotorua geothermal field was a field under stress due to excessive exploitation. Large quantities of fluid were withdrawn and used in surface equipment in an inefficient manner. The downhole heat exchanger (DHE) is one alternative energy extraction system that can be considered, in order to conserve geothermal fluid and provide energy for space-heating systems, domestic water heating and thermal pools. An experiment to determine the performance characteristics of a small DHE fitted to a discussed Rotorua production well is described in this paper, with some comments on the likely long-term effects on the reservoir. It is concluded that such a system would be able to provide the continuous heating requirements for about 8 Rotorua homes, and would save between 20 and 80 t/day of withdrawal from the field.

Freeston, D.H.; Dunstall, M.G. (Auckland Univ. (New Zealand). Geothermal Inst.)

1992-04-01

349

Gentilly-2 moderator heat exchanger repair  

Energy Technology Data Exchange (ETDEWEB)

At the time of an unscheduled outage for a problem with the fuelling machine, an operator noted a sound coming from the inlet moderator heat exchanger 3211-HX1. The noise was reported as a loose object knocking around between the tubesheet and the inlet piping. Upon separating the tubesheet from the Heat Exchanger, the tubesheet overlay and tubes extensions were found severely damaged. The repair work would be required to be performed insitu in a highly contaminated environment during end of the year where obtaining manpower resources were difficult. The team work between Hydro-Quebec and Babcock and Wilcox Canada Nuclear Services and use of non-conventional tooling was a big part of the success for this project. The repair started on December 21st, 2007 and the vessel was turned over to HQ on January 24, 2008. (author)

Valois, S. [Hydro-Quebec, Becancour, Quebec (Canada); Hartwick, D. [Babcock and Wilcox Canada, Nuclear Services, Cambridge, Ontario (Canada)

2008-07-01

350

Tubular heat exchanger, for nuclear installations  

International Nuclear Information System (INIS)

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

1976-07-29

351

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

352

Selection of materials for heat exchangers  

International Nuclear Information System (INIS)

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

1997-04-01

353

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

2009-02-01

354

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.

Syka Tomáš

2012-04-01

355

Verification on reliability of heat exchanger for primary cooling system  

International Nuclear Information System (INIS)

Prior to the JMTR refurbishment, verification on reliability of the heat exchangers for primary cooling system was carried out to investigate an integrity of continuously use component. From a result of the significant corrosion, decrease of tube thickness, crack were not observed on the heat exchangers, and integrity of heat exchangers were confirmed. In the long terms usage of the heat exchangers, the maintenance based on periodical inspection and a long-term maintenance plan is scheduled. (author)

2010-01-01

356

Innovative, counterflow gas/fine solids, direct contact heat exchanger  

Science.gov (United States)

The Aerojet Energy Conversion Company has completed the first phase of study for development of a heat exchanger. The heat exchanger, a highly efficient, low cost concept, is a candidate for application in process manufacturing industries such as cement, lime, or glass. The analytical effort was to establish the heat exchanger performance via computer modeling and analysis; the experimental effort was to demonstrate the heat exchanger performance.

Mah, C. S.

1987-10-01

357

Cross-flow countercurrent involute-tube heat exchangers  

International Nuclear Information System (INIS)

The value of giving an involute form to the tubes of a cross-flow countercurrent heat exchanger (tubes all identical in shape and developed length), both for heat exchange and to absorb differential expansion is demonstrated. Two applications pertaining to nuclear heat exchangers, involving steam generators, one heated by gaseous helium (superheated steam 5330C, 112 bar) and the second by liquid sodium (superheated steam 4870C, 181 bar) are discussed. The thermal power exchanged is calculated respectively for the superheater, evaporator and economizer, together with the heat transfer area, developed length of a tube, general dimensions, and pressure drop of both heat exchanger fluids

1983-01-01

358

Joule-Thomson heat exchanger and cryostat  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a refrigerator of the type wherein a fluid is passed through the high pressure tube of a heat exchanger and then expanded through a Joule-Thomson orifice to produce refrigeration proximate the Joule-Thomson orifice. The improvement described here comprises: fibrous material disposed in the Joule-Thomson orifice which is deformed to fix the fibrous material in place, whereby the fibrous material and deformed orifice result in an orifice with large flow impedance.

Steyert, W.A.

1987-03-31

359

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 coolant flows through the inlet and outlet. Air, flowing over the outside surface of the sleeve and the inside surface of the chassis meter, cools the vehicle coolant. SMH - MCC Smart, car concepts (...

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

1997-01-01

360

Robust controllers for a heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A robust controller with uncertainty estimation is proposed for temperature control of process fluid in a fluid-fluid heat exchanger. The controller comprises an approximate input-output linearizing feedback and an observer-based uncertainty estimator. The performance of the proposed controller is evaluated by simulation for both regulatory and servo problems. The simulation results show the effectiveness of the present controller and its robustness to modeling errors and disturbances.

Alvarez-Ramirez, J.; Cervantes, I.; Femat, R.

1997-02-01

 
 
 
 
361

Conceptualizations for cleaning OTEC heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

A critical operating aspect of Ocean Thermal Energy Conversion (OTEC) plants is the maintenance of clean surfaces on the seawater-side of the heat exchangers. The objective of this program was to assess the state of the art of biofouling control techniques and to evaluate the potential of these existing methods for solving the biofouling problems in the OTEC system. The first task of the program involved an in-depth review and discussion of various fouling control methods including water treatment, surface conditioning, and cleaning techniques. The methods considered applicable to OTEC were identified. This volume summarizes the second task of the program. The compatibility of the various cleaning and fouling control techniques with the different proposed heat exchanger designs and materials are discussed. Also provided are conceptual illustrations for adapting and incorporating the methods into an OTEC power plant. These conceptual designs suggest means for overcoming some of the shortcomings of the techniques which are considered suitable, however, detailed designs of the modified systems are beyond the scope of this report. Chlorination, chemical cleaning, Amertap recirculating sponge rubber balls, and MAN flow-driven brushes are the methods considered applicable for tubular heat exchangers with seawater inside the tubes. Water jets are suggested for the open-cycle and the ''trombone'' (Applied Physics Laboratory) heat exchanger designs. Although none of the methods are immediately applicable to OTEC in their present configuration, in several cases only minor developmental efforts should produce designs which can satisfy the stringent OTEC cleanliness requirements. Further research and development appear warranted for a number of other methods which indicate promise for long-range applicability. Specific recommendations are included.

Rice, M.S.; Hagel, D.; Conn, A.F.

1978-09-01

362

Heat exchangers and methods of construction thereof  

International Nuclear Information System (INIS)

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

1982-07-16

363

Energetic evaluation of R 22-alternatives in a test rig with plate heat exchangers (PHE); Energetische Bewertung von R 22-Alternativen in einer Experimentieranlage mit Platten-Waermeuebertragern  

Energy Technology Data Exchange (ETDEWEB)

In [1] and [2] and R502 alternatives R407A, R407B, R407C, R404A and R507 have been compared energetically with R22 by system testing. The configurations were air cooled evaporator, annular tube evaporator, shell and tube condenser and annular condenser. After testing R407C and R404A in systems with flat plate heat exchangers, the comparison with R22 has been done under constant conditions (constant refrigeration capacity and constant temperature difference of 5 K in the secondary refrigerant loop and in the cooling water loop). The smallest reduction of the C.O.P. (<8%) could be found for R407C as well as R404A using plate heat exchanger (annular heat exchanger<15%). The reason for the positive behaviour of the R407C system is mainly the increase of the dew point temperature at the exit of the evaporator in comparison with annular evaporation. (orig.) [Deutsch] In [1] und [2] wurden die R22- bzw. R502-Alternativen R407A, R407B, R407C, R404A und R507 einer vergleichenden energetischen Bewertung zu R22 durch Anlagenleistungsmessungen mit Anlagenkonfigurationen, die sich mit luftbeaufschlagtem Verdampfer, Koaxial-Verdampfer, Rohrbuendel- und Koaxial-Verfluessiger kombinieren lassen, unterzogen. Anknuepfend an diese Untersuchungen wurde fuer die FKW-Gemische R407C und R404A bei Einsatz von Platten-Waermeuebertragern eine energetische Bewertung im Vergleich zu R22 durch Anlagenleistungsmessungen bei konstanten aeusseren Bedingungen (Temperaturspreizung des Kaelte-/Waermetraegers 5 K, konstante Kaelteleistung) vorgenommen. Die geringsten Leistungszahleinbussen (<8%) im Vergleich zu R22 traten sowohl mit R407C als auch mit R404A bei Einsatz von Platten-Waermeuebertragern auf (Koaxial-Waermeuebertrager<15%). Ursache fuer dieses guenstige Verhalten bei Einsatz von R407C ist im wesentlichen die groessere Taupunkttemperaturanhebung am Verdampferaustritt im Vergleich zum Koaxial-Verdampfer. (orig.)

Ahnefeld, G. [Institut fuer Luft- und Kaeltetechnik GmbH, Dresden (Germany)

1997-10-01

364

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

365

Performance Investigation of Plate Type Heat Exchanger (A Case Study  

Directory of Open Access Journals (Sweden)

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

Simarpreet Singh

2014-04-01

366

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

367

OXIDE DISPERSION-STRENGTHENED HEAT EXCHANGER TUBING  

Energy Technology Data Exchange (ETDEWEB)

Oxide dispersion strengthened (ODS) alloys (e.g. the INCOLOY{reg_sign} MA956 alloy) are known for their excellent high temperature properties and are prime candidate materials for the construction of very high temperature heat exchangers that will be used in Vision 21 power plants. The main limitation of these materials is their poor weldability. Commercially available ODS tubing also tends to exhibit relatively poor circumferential creep strength due to current processing practices resulting in a fine grain size in the transverse direction. Thus far, these two characteristics of the ODS tubing have restricted its use to mostly non-pressure containing applications. The objectives of this program are to develop: (a) an MA956 tube with sufficient circumferential creep strength for long term use as heat exchanger tubing for very high temperatures; (b) a welding technique(s) for producing adequate joints between an MA956 tube and an MA956 tube, and an MA956 tube and an INCONEL 601 tube; (c) the bending strain limits, below which recrystallization will not occur in a MA956 tube during normal operation; and (d) the high temperature corrosion limits for the MA956 alloy with respect to working-fluid side and fireside environments. Also, this program seeks to generate data for use by heat exchanger designers and the ASME Boiler and Pressure Vessel Code, and perform an analysis of the mechanical property, tube bending, and corrosion data in order to determine the implications on the design of a very high temperature heat exchanger (T>1093 C/2000 F). After one year, work is currently being conducted on increasing the circumferential strength of a MA956 tube, developing joining techniques for this material, determining the tube bending strain limits, and establishing the high temperature corrosion parameters for the MA956 alloy in environments expected to be present in Vision 21 power plants. Work in these areas will is continuing into the next fiscal year, with success anticipated to produce innovative developments that will allow the reliable use of ODS alloys for heat exchanger tubing, as well as a variety of applications previously not possible with metallic materials.

Harper, Mark A.

2001-11-06

368

Materials for fluidized bed heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

In order to increase the steam parameters in combustion units, several new approaches have been proposed. New materials have been tested, but they seldom have been a sufficient solution. Metallic coatings sprayed on superheater tubes have been noted to reduce erosion and corrosion in selected cases. New plant designs have been tested. However, most of these solutions have at least one special feature, which prevents using them as a general solution applicable to all new boiler units. Fluidised bed combustion units, and especially circulating fluidised bed (CFB) combustors have gained reputation as one of the most feasible means of solid fuel combustion. These units have one major benefit over other technologies: possibility to utilise the re-circulated solids for heat generation. This allows using fluidised bed heat exchangers (FBHE), which are one of the most promising novel solutions to improve the efficiency of solid fuel combustion units. Selecting optimal materials for such heat exchangers is not straightforward due to several special demands, such as high heat flux and continuous erosion. (orig.)

Makkonen, P.; Maekipaeae, M. [VTT Processes, Espoo (Finland)

2004-05-01

369

Technology of heat exchangers; Technologie des echangeurs thermiques  

Energy Technology Data Exchange (ETDEWEB)

This book describes the main types of heat exchangers with their characteristics: identification, dimensioning, enhancement of exchanges, evaporation and condensation, distribution, fouling, corrosion, vibrations, and regulatory aspects of the use of heat exchangers. The first chapter presents the basic concepts of heat exchangers, while the second chapter is devoted to a description of classical and specific exchangers with several illustration schemes. Then, follows a general analysis of exchangers dimensioning with some examples of calculation. Another chapter concerns the technical-economical optimization of exchangers, which is one of the main worry of designers and manufacturers. (J.S.)

Bontemps, A.; Garrigue, A.; Goubier, Ch.; Huetz, J.; Marvillet, Ch.; Mercier, P.; Vidil, R.

1998-07-01

370

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

371

Probabilistic study of a porous heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a probabilistic one-dimensional finite element model for heat transfer processes in a porous heat exchanger. The Galerkin approach is used to develop the finite element matrices. Some of the submatrices are asymmetric due to the presence of the flow term. The Neumann expansion is used to write the temperature distribution as a series of random variables, and the expectation operator is applied to obtain the mean and deviation statistics. To demonstrate the feasibility of the formulation, a one-dimensional heat transfer model of a superfluid flow through a porous media is considered. Results of this formulation agree well with the Monte-carlo simulations and the analytical solutions.

Agrawal, O.P.; Lin, X. [Southern Illinois Univ., Carbondale, IL (United States). Dept. of Mechanical Engineering and Energy Processes

1995-12-31

372

Heat exchanger with several modules in parallel  

International Nuclear Information System (INIS)

A heat exchanger with several modules in parallel is proposed. Each module includes a bundle of tubes for circulation of a fluid to be heated, vaporised and/or superheated in them, placed between two tube plates in a casing for the flow of a heating fluid formed of an alkaline molten metal. The alkaline molten metal intake manifolds at the upper part of the modules are connected to a common supply bottle. The alkaline molten metal outlet manifolds at the bottom of the modules are also connected to a common discharge bottle. The axes of the modules are distributed with a constant angular deviation on a cylinder the axis of which is the vertical axis common to the supply and discharge bottles

1975-01-01

373

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 ?

1990-11-25

374

Regenerative rotary heat exchanger for heat recovery in residential ventilation  

Energy Technology Data Exchange (ETDEWEB)

Increased energy costs have brought about increased concern by building owners as well as governments about the operating costs and energy budgets for buildings and power plants. This growing energy conservation consciousness has brought a considerable interest in reclaiming waste heat from residential, commercial, industrial, and institutional ventilation systems. Based on theoretical considerations, the design and performance of a small rotary heat exchanger for residential houses is discussed. Laboratory results reveal a high sensible heat recovery maximum effectiveness of 85 per cent with acceptable levels of pressure drop and cross leakage. Cost saving analysis indicates annual energy savings up to 15 per cent, with even larger savings in the size of the heating and cooling equipment up to 42 per cent. As expected the greatest savings could occur when large amounts of outside air are required for ventilation.

Younis, M.; Shoukry

1983-10-01

375

Microchannel Heat Exchangers with Carbon Dioxide  

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-09-15

376

Analysis of Heat Transfer Enhancement in Spiral Plate Heat Exchanger  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 d...

Kaliannan Saravanan; Rangasamy Rajavel

2009-01-01

377

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

CERN Document Server

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

378

Automatic evolution of heat exchanger networks with simultaneous heat exchanger design  

Energy Technology Data Exchange (ETDEWEB)

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. (author)

Liporace, F.S.; Pessoa, F.L.P.; Queiroz, E.M. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica. Dept. de Engenharia Quimica]. E-mail: lipo@h2o.eq.ufrj.br; lipo@hexanet.com.br

1999-03-01

379

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

1999-03-01

380

AUTOMATIC EVOLUTION OF HEAT EXCHANGER NETWORKS WITH SIMULTANEOUS HEAT EXCHANGER DESIGN  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English 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 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.

 
 
 
 
381

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

382

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

383

Heat exchange apparatus for a reactor  

International Nuclear Information System (INIS)

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

1980-01-01

384

Heat Exchanger Design for Solar Gas-Turbine Power Plant  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this project is to select appropriate heat exchangers out of available gas-gas heat exchangers for used in a proposed power plant. The heat exchangers are to be used in the power plant for the purposes of waste heat recovery, recuperation and intercooling.In selecting an optimum heat exchanger for use, the PCHE was identified as the best candidate for waste heat recovery and recuperation. In order to ascertain the viability of this assertion the PCHE was designed and a 1D modeling ...

Yakah, Noah

2012-01-01

385

High-temperature self-circulating thermoacoustic heat exchanger  

Science.gov (United States)

Thermoacoustic and Stirling engines and refrigerators use heat exchangers to transfer heat between the oscillating flow of their thermodynamic working fluids and external heat sources and sinks. An acoustically driven heat-exchange loop uses an engine's own pressure oscillations to steadily circulate its own thermodynamic working fluid through a physically remote high-temperature heat source without using moving parts, allowing for a significant reduction in the cost and complexity of thermoacoustic and Stirling heat exchangers. The simplicity and flexibility of such heat-exchanger loops will allow thermoacoustic and Stirling machines to access diverse heat sources and sinks. Measurements of the temperatures at the interface between such a heat-exchange loop and the hot end of a thermoacoustic-Stirling engine are presented. When the steady flow is too small to flush out the mixing chamber in one acoustic cycle, the heat transfer to the regenerator is excellent, with important implications for practical use.

Backhaus, S.; Swift, G. W.; Reid, R. S.

2005-07-01

386

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

387

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

388

Heat Exchanger Anchors for Thermo-active Tunnels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2013-01-01

389

Fluid dynamical considerations on heat exchanger networks  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

390

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

2000-03-01

391

Auxiliary heat-exchanger flow-distribution test  

International Nuclear Information System (INIS)

The Auxiliary Heat Exchanger Flow Distribution Test was the first part of a test program to develop a water-cooled (tube-side), compact heat exchanger for removing heat from the circulating gas in a High-Temperature Gas-Cooled Reactor (HTGR). The function of this heat exchanger is to provide emergency cooldown for the HTGR. It is designed to operate over a wide range of helium or helium mixture conditions from depressurized to pressurized reactor operations

1983-09-25

392

Fan supplied heat exchanger fin performance under frosting conditions  

Energy Technology Data Exchange (ETDEWEB)

In this paper, a validated numerical model for frost growth on heat exchange fins is modified to simulate a fan-supplied finned heat exchanger under refrigeration frosting conditions. It is found that frost growth on refrigeration heat exchangers causes a dramatic drop in the fin heat rate, airflow rate, and fin efficiency while the pressure drop increases. A sensitivity study shows the effects of changing several design parameters including the type of fan. (Author)

Hong Chen; Besant, Robert W. [Saskatchewan Univ., Dept. of Mechanical Engineering, Saskatoon, SK (Canada); Thomas, Leena [Corning Cable Systems, Saskatoon, SK (Canada)

2003-01-01

393

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

1991-08-25

394

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

1991-11-01

395

Downhole heat exchanger experiments: Rotorua geothermal field  

Energy Technology Data Exchange (ETDEWEB)

The need for research for the application of downhole heat exchangers (DHE) in the Rotorua Geothermal field has arisen from the increased use of DHEs for heating and the limited performance information available to assist effective and efficient design. An experiment was designed in which two 4 in. diameter wells located at the Works depot in Te Ngae Road have been used. RR679 is fitted with a U tube DHE and well RR520, approximately 15 m away, is monitored for interference effects. The design and installation of the test facility is described and results of some experiments presented. A theoretical model of the installation is also presented which enables studies to be made of the major well and DHE design parameters.

Dunstall, M.; Freeston, D.H. (Univ. of Auckland (New Zealand))

396

Intermediate heat exchanger project for Super Phenix  

International Nuclear Information System (INIS)

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

1975-09-01

397

Gas and solid particulate material heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

This patent describes an apparatus for carrying out heat exchange between a gas and solid particulate material comprising a casing having an upper inlet for particulate material and a lower outlet for particulate material and a lower grate mounted in the casing extending from the upper inlet to the lower outlet for supporting a bed of particulate material for movement from the inlet to the outlet along the lower grate. A means defines an upper grate mounted in the casing and is spaced from the lower grate including generally vertically oriented slats, each spaced from and positioned below a preceding slat in the direction from the inlet toward the outlet for defining the top of the bed of material while permitting the bed of material to expand. The casing includes an inlet for gas on one side of the casing and an outlet for gas on the other side of the casing whereby gas flows from the inlet through the lower grate, the bed of material and through the upper grate to the outlet for gas for carrying out heat exchange between the gas and the solid particulate material. Each of the slats is perforated to permit gas and fine material to pass therethrough while retaining the bed of material on the lower grate.

Kreisberg, A.J.; Warshawsky, J.

1986-12-16

398

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

399

Bank of heat exchangers intended for liquid cooling or heating  

International Nuclear Information System (INIS)

The invention concerns the heat exchangers cooling a significant volume of water, by straight natural air draught, such as the towers or the draught ducts of dry type air coolers. In a compact form, they enable water cooling problems to be solved in certain industrial installations such as isotope separation plants. The design of this bank of exchangers is also such that its cost is considerably diminished in relation to that of conventional banks. To this effect, this bank is composed of one or several rows of thin flexible plastic pockets forming as many water or other liquid sheets, connected to intake and discharge collectors and arranged one after the other and separated by air flow gaps. These pockets are suspended from one of their ends to hangers fixed to the assembly frame whilst restrictors prevent the pockets from swelling so avoiding any contact between them in order to maintain the air circulation gaps between them

1975-01-01

400

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.  

Science.gov (United States)

...exchanger is a device, consisting of a heat exchange system used in extracorporeal circulation to warm or cool the blood or perfusion fluid flowing through the device. (b) Classification. Class II (performance...

2010-04-01

 
 
 
 
401

A heat exchanger filled with pebbles. Waermetauscher mit Kieselsteinen  

Energy Technology Data Exchange (ETDEWEB)

The heat contained in the exit air of animal shelters can be recovered by heat exchangers. Searching for a budget-priced solution the authors investigated a renewable heat exchanger with a filling of pebbles, whose principle of function and measuring results are reported in this paper. (orig.)

Georgiev, R. (Institut fuer Zootechnik und Veterinaermedizin, Stara Zagora (Bulgaria))

1993-01-01

402

Alfa-Laval plate heat exchangers for the power industries  

International Nuclear Information System (INIS)

Within power-generating plants, the transfer and conversion of heat energy of very large quantity are carried out in the process of energy conversion, accordingly the importance of heat exchangers is very high. Heretofore, multi-tube heat exchangers have been used mostly, but Alfa-Laval group developed the heat exchanger with very high efficiency to incorporate it effectively into a power-generating plant. In this plate type heat exchanger, the heat transfer efficiency is very high, and the quantity of stagnation is small as it is compact, consequently it is suitable to the secondary cooling for power-generating plant or the heat exchange of high-priced liquid heat media such as heavy water. Originally, plate type heat exchangers were used for food and chemical industries, therefore the prevention of mixing two liquids, sanitary construction, and corrosion resistance were required. Then they were adopted in iron and steel industry, and large thermal load, large heat transfer area and corrosion resistance to sea water were required. They were adopted in a nuclear power plant for the first time in 1964. In this heat exchanger, channels are formed with corrugated metal sheets, and titanium, stainless steels, Incoloy, Hastelloy and others are used as occasion demands. The Alfa-Laval heat exchangers and their features are explained. (Kako, I.)

1979-01-01

403

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

404

Soldering of heat exchange equipment for power plants  

International Nuclear Information System (INIS)

Main materials and solders used for fabrication of heat exchange equipment of power plants in foreign coutries are considered. Recommendations on soldering procedure of recuperative and regenerative heat exchangers are given. Indexes of mechanical and corrosion properties of soldered joints of austenitic steels and heat-resisting alloys are given as well. Methods of destructive and nondestructive testing of soldered joints quality are described

1980-01-01

405

Heat transfer enhancement for fin-tube heat exchanger using vortex generators  

International Nuclear Information System (INIS)

Vortex generators are fabricated on the fin surface of a fin-tube heat exchanger to augment the convective heat transfer. In addition to horseshoe vortices formed naturally around the tube of the fin-tube heat exchanger, longitudinal vortices are artificially created on the fin surface by vortex generators. The purpose of this study is to investigate the local heat transfer phenomena in the fin-tube heat exchangers with and without vortex generators, and to evaluate the effect of vortices on the heat transfer enhancement. Naphthalene sublimation technique is employed to measure local mass transfer coefficients, then analogy equation between heat and mass transfer is used to calculate heat transfer coefficients. Experiments are performed for the model of fin-circular tube heat exchangers with and without vortex generators, and of fin-flat tube heat exchangers with and without vortex generators. Average heat transfer coefficients of fin-flat tube heat exchanger without vortex generator are much lower than those of fin-circular tube heat exchanger. On the other hand, fin-flat tube heat exchanger with vortex generators has much higher heat transfer value than conventional fin-circular tube heat exchanger. At the same time, pressure losses for four types of heat exchanger is measured and compared

2002-01-01