WorldWideScience
1

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

International Nuclear Information System (INIS)

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

2

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

3

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

4

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

Directory of Open Access Journals (Sweden)

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

Dan CONSTANTINESCU

2011-07-01

5

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

OpenAIRE

Shell and tube heat exchangers are extensively used in boilers, oil coolers, pre-heaters, condensers etc. They are also having special importance in process application as well as refrigeration and air conditioning industries. The present paper emphasizes on heat transfer characteristics of shell and tube heat exchangers with the aid of hiTRAN wire matrix inserts is been studied. Investigations were made on effect of mass flow rate of water on heat transfer characteristics in ...

Manoj; Mulla, A. M.

2014-01-01

6

Three-dimensional computer simulation of shell and tube heat exchangers  

International Nuclear Information System (INIS)

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

7

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

International Nuclear Information System (INIS)

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

8

Numerical studies of combined multiple shell-pass shell-and-tube heat exchangers with helical baffles  

OpenAIRE

In order to simplify the manufacture and improve the heat transfer performance, we have invented a combined multiple shell-pass shell-and-tube heat exchanger. The novel combined multiple shell-pass shell-and-tube heat exchanger (CM-STHXs) with continuous helical baffles in the outer shell-pass and other different baffles in the inner shell-pass was compared with conventional STHX with segmental baffles by Computational Fluid Dynamics method. The numerical results show tha...

Chen, Guidong; Zeng, Min; Wang, Qiuwang

2008-01-01

9

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

10

Comparison of shell-and-tube with frame-and-plate-type heat exchangers for the MIT research reactor upgrade  

International Nuclear Information System (INIS)

This paper discusses a comparison of shell-and-tube with frame-and-plate-type heat exchangers for the proposed upgrade of the Massachusetts Institute of Technology research reactor (MITR). The comparison is based on the following considerations: thermal-hydraulic performance, maintenance, personnel dose rate, and pricing

11

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

12

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

International Nuclear Information System (INIS)

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

13

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

International Nuclear Information System (INIS)

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

14

A new design approach for shell-and-tube heat exchangers using imperialist competitive algorithm (ICA) from economic point of view  

International Nuclear Information System (INIS)

Highlights: ? A new shell and tube heat exchanger optimization design approach is developed. ? Design optimization is performed using imperialist competitive optimization (ICA) algorithm. ? The capital investment, annual cost and consequently total cost are minimized by applying ICA technique. ? Proposed a quick approach to optimal design of heat exchangers with very low run time. - Abstract: Cost minimization of shell-and-tube heat exchangers is a key objective. Traditional design approaches besides being time consuming, do not guarantee the reach of an economically optimal solution. So, in this research, a new shell and tube heat exchanger optimization design approach is developed based on imperialist competitive algorithm (ICA). The ICA algorithm has some good features in reaching to the global minimum in comparison to other evolutionary algorithms. In present study, ICA technique 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 and baffle spacing. Based on proposed method, a full computer code was developed for optimal design of shell and tube heat exchangers and different test cases are solved by it to demonstrate the effectiveness and accuracy of the proposed algorithm. Finally the results are compared to those obtained by literature approaches. The obtained results indicate that the ICA algorithm can be successfully applied for optimal design of shell and tube heat exchangers with higher accuracy in less computational time

15

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)

16

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

17

Field applications of double enhanced tubes in shell-and-tube and air-cooled heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Tubular heat exchangers, such as shell-and-tube and air-cooled exchangers, are used for the majority of process heat transfer in the petroleum and petrochemical industries. Dual enhancement techniques provide more compact grassroots designs of new equipment and maximize heat transfer rates in existing equipment. In grassroots applications, weight, plot space, total installed costs, and energy requirements are reduced. In retrofit applications, dual enhancement techniques offer a ``drop-in`` technology which maximizes the use of existing equipment, piping, and structure. This technology is especially attractive considering the emphasis on minimizing both project costs and pre-investment strategies; but its application requires careful consideration of numerous factors including available pressure drop, variations in operating conditions, operating experience in similar service, ease of maintenance, and mechanical reliability. Two field applications in the process industry are presented: high-finned tubes with turbulence promoters in an air-cooled heat exchanger, and integral-finned tubes with internal ribs in a shell-and-tube exchanger. In addition, a logic diagram for initial screening of applications using enhanced tubes is included.

Curcio, L.A.; Fischer, I.M. [Exxon Research and Engineering Co., Florham Park, NJ (United States); Rudy, T.M. [Exxon Research and Engineering Co., Baytown, TX (United States)

1995-12-31

18

Numerical simulation of heat transfer enhancement in shell side of shell-and-tube heat exchanger with leading type shutter baffles  

International Nuclear Information System (INIS)

For overcoming the contradiction between the performance improvement and fluid flow resistance increase in shell-and-tube heat exchanger, a new concept of 'Sideling Flow' in shell side is presented, and a type of new high efficiency energy saving shell-and-tube heat exchanger with leading type shutter baffles in shell side, sideling flow heat exchanger is invented. Besides, the 'Field Synergy Principle' is adopted to analyze its heat transfer enhancement mechanism, and it is indicated that there is the perfect synergy between the velocity field and temperature grads field in shell side of this type of new heat exchanger. Effects of the structure parameters on the fluid flow and heat transfer are investigated through numerical simulation, and the numerical results are in good agreement with the experimental data. (authors)

19

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.

2012-06-01

20

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

21

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.

2014-10-01

22

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

International Nuclear Information System (INIS)

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

23

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

24

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

International Nuclear Information System (INIS)

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

25

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

Directory of Open Access Journals (Sweden)

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

Hisham Hassan Jasim

2013-01-01

26

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

Directory of Open Access Journals (Sweden)

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

Raj Karuppa Thundil R.

2012-01-01

27

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

International Nuclear Information System (INIS)

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

28

Shell-and-tube exchangers: Pressure drop and heat transfer in shellside downflow condensation  

Science.gov (United States)

ESDU 84023 considers tubular condensers in which the coolant flows in horizontal tubes across which a pure vapor flows. It gives methods, derived empirically, for estimating total pressure drop (in two contributions, local pressure gradient across the tube bank as a function of quality, that is ratio of vapor mass flow rate to total mass flow rate, and nozzle pressure drop) and overall heat transfer (from the local shellside coefficient as a function of quality together with contributions from coolant, tube, and fouling). A step-by-step calculation procedure based on those methods shows how they may be used to check the adequacy of a design to meet thermal requirements and pressure drop limitations, to estimate the outlet conditions from a given condenser, or to evaluate test results on a condenser to determine, for example, its fouling resistance.

1984-09-01

29

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

Scientific Electronic Library Online (English)

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

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

2014-08-01

30

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

International Nuclear Information System (INIS)

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

31

Analyzing the effect on heat transfer due to nonuniform distribution of liquid flow among the tubes of a shell-and-tube heat exchanger  

Science.gov (United States)

A method is proposed using which nonuniform distribution of liquid flow among the tubes of a shell-and-tube apparatus can be taken into account by means of a statistical distribution function. A formula showing interrelation of this function with the indicator of heat transfer intensity in the apparatus tube space is given.

Zinkevich, A. I.; Sharifullin, V. N.; Sharifullin, A. V.

2010-09-01

32

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

Scientific Electronic Library Online (English)

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

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

2014-04-01

33

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

Scientific Electronic Library Online (English)

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

Fiderman, Machuca; Oscar, Urresta.

2008-06-01

34

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

OpenAIRE

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...

Siregar, Franky S.

2011-01-01

35

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

36

Shell-and-tube type latent heat thermal energy storage: numerical analysis and comparison with experiments  

Science.gov (United States)

The melting process of industrial grade paraffin wax inside a shell-and-tube storage is analyzed by means of numerical simulation and experimental results. For this purpose, the enthalpy porosity method is extended by a continuous liquid fraction function. The extended method is tested using results gained from a gallium melt test inside a rectangular enclosure.

Rösler, Fabian; Brüggemann, Dieter

2011-08-01

37

Heat exchanger optimization  

Science.gov (United States)

A computer code was developed which would analyze a shell-and-tube heat exchanger, and it was used in conjunction with a computer code for numerical optimization program. The problem is to find the smallest shell-and-tube heat exchanger with the minimum number of exchangers in series and parallel which will satisfy the heat duty and pressure drop requirements within the constraints imposed. The MINOS (Modular In-core Nonlinear Optimization System) programming code was used in the optimization of a shell-and-tube heat exchanger. MINOS purpose is to optimize a user written objective function. For heat exchanger design, it is necessary to develop two FORTRAN subroutines in order to analyze a heat exchanger. To get the generalized optimal heat exchanger design, the calculation method and data in Process Heat Transfer by Kern, was used. All the data, including material specifications were given as typical. Three types of case studies were studied and are discussed.

Lee, Ik-Sang

38

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

39

Effects of spray axis incident angle on heat transfer performance of rhombus-pitch shell-and-tube interior spray evaporator  

International Nuclear Information System (INIS)

An interior spray method is proposed for enhancing the heat transfer performance of a compact rhombus-pitch shell-and-tube spray evaporator. The experimental results show that the shell-side heat transfer coefficient obtained using the proposed spray method is significantly higher than that achieved in a conventional flooded-type evaporator. Four different spray axis incident angles (0 .deg., 45 .deg., 60 .deg. and 75 .deg.) are tested in order to investigate the effect of the spray inclination angle on the heat transfer performance of the spray evaporator system. It is shown that the optimal heat transfer performance is obtained using a spray axis incident angle of 60 .deg.

40

Heat Exchanger  

International Nuclear Information System (INIS)

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

41

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

42

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)

43

Shell & Tube Type Heat Exchangers: An Overview  

OpenAIRE

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; Raj Rajat Verma; Piyush Shanker Verma; Srivastava, A. K.

2014-01-01

44

Liquid metal operated heat exchanger  

International Nuclear Information System (INIS)

This invention relates to a heat exchanger arrangement of the shell and tube type especially adapted for the use of high temperature liquid metal as a heating medium. The arrangement incorporates a tube bundle comprising a plurality of bayonet tube assemblies through which the liquid metal is circulated in indirect heat exchange relation with vaporizable fluid that flows through the shell. The tube assemblies incorporate a double walled bayonet tube containing a gas space which provides a thermal barrier to minimize heat loss from the heating medium. Various embodiments of evaporator and evaporator-superheater organizations utilizing the heat exchanger arrangement are described. (U.S.)

45

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

International Nuclear Information System (INIS)

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

46

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

47

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

International Nuclear Information System (INIS)

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

48

Heat exchanger with leak detecting double wall tubes  

Science.gov (United States)

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

49

A Simple Tubesheet Layout Program for Heat Exchangers  

OpenAIRE

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

Murali, S.; Rao, Y. B.

2008-01-01

50

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

International Nuclear Information System (INIS)

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

51

Heat exchanger  

International Nuclear Information System (INIS)

A heat exchanger for fluids, such as liquids, steam, gases, etc. The heat exchanger has a closed container provided with an inlet and an outlet for one fluid and heat exchanging means for the other fluid provided in the container. The heat exchanging means are in connection with closed inlet and outlet sections separated from the interior of the container. The heat exchanging means comprise an element with two separate channels elongated in relation to the container interior, the channels at one end being connected to sealed inlet and outlet sections. The heat exchanging means have at the other end a reversion compartment for transferring the other fluid from one channel to the other channel. (author)

52

Heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

A heat exchanger for fluids, such as liquids, steam, gases, etc. The heat exchanger has a closed container provided with an inlet and an outlet for one fluid and heat exchanging means for the other fluid provided in the container. The heat exchanging means are in connection with closed inlet and outlet sections separated from the interior of the container. The heat exchanging means comprise an element with two separate channels elongated in relation to the container interior, the channels at one end being connected to sealed inlet and outlet sections. The heat exchanging means have at the other end a reversion compartment for transferring the other fluid from one channel to the other channel. (author).

Grunditz, S.

1996-04-03

53

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.

54

Multidimensional numerical modeling of heat exchangers  

International Nuclear Information System (INIS)

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

55

Heat exchanger design based on economic optimisation  

Energy Technology Data Exchange (ETDEWEB)

Owing to the wide utilization of heat exchangers in industrial processes, their cost minimization is an important target for both designers and users. Traditional design approaches are based on iterative procedures which gradually change design parameters until a satisfying solution, which meets the design specifications, is reached. However, such methods, besides being time consuming, do not guarantee the reach of an economically optimal solution. In this paper a procedure for optimal design of shell and tube heat exchangers is proposed, which utilizes a genetic algorithm to minimize the total cost of the equipment including capital investment and the sum of discounted annual energy expenditures related to pumping. In order to verify the capability of the proposed method, three case studies are also presented showing that significant cost reductions are feasible with respect to traditionally designed exchangers. In particular, in the examined cases a reduction of total costs up to more than 50% was observed. (author)

Caputo, Antonio C.; Pelagagge, Pacifico M.; Salini, Paolo [University of L' Aquila, Engineering Faculty, Monteluco di Roio 67100, L' Aquila (Italy)

2008-07-15

56

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

57

Evaluation Methodology for Advance Heat Exchanger Concepts Using Analytical Hierarchy Process  

Energy Technology Data Exchange (ETDEWEB)

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

Piyush Sabharwall; Eung Soo Kim

2012-07-01

58

Plate type heat exchanger for Reaktor TRIGA PUSPATI  

International Nuclear Information System (INIS)

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

59

Development of VB Based Software For Design And Analysis of Heat Exchangers  

OpenAIRE

The exchange of heat is one of the most important processes in the mechanical industry and heat exchanger is the major equipment used to transfer heat from one medium to another. This project work on the Computer Aided Design (CAD) of shell and tube, double pipe and spiral coil heat exchanger aims to provide an easy way to design it. A case study question was taken and all the necessary calculations in the thermal design are carried out using standard method of heat exchanger ...

Joshi, Prof Sandeep M.; Iqbal Mujawar2

2014-01-01

60

Design study of plastic film heat exchanger  

Science.gov (United States)

This report presents the results of an effort to develop and design a unique thermoplastic film heat exchanger for use in an industrial heat pump evaporator system and other energy recovery applications. The concept for the exchanger is that of individual heat exchange elements formed by two adjoining and freely hanging plastic films. Liquid flows downward in a regulated fashion between the films due to the balance of hydrostatic and frictional forces. The fluid stream on the outside of film may be a free-falling liquid film, a condensing gas, or a noncondensing gas. The flow and structural principles are similar to those embodied in an earlier heat exchange system developed for use in waste water treatment systems (Sanderson). The design allows for high heat transfer rates while working within the thermal and structural limitations of thermoplastic materials. The potential of this new heat exchanger design lies in the relatively low cost of plastic film and the high inherent corrosion and fouling resistance. This report addresses the selection of materials, the potential heat transf er performance, the mechanical design and operation of a unit applied in a low pressure steam recovery system, and the expected selling price in comparison to conventional metallic shell and tube heat exchangers.

Guyer, E. C.; Brownell, D. L.

1986-02-01

61

Heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

The heat exchanger described is adapted to be installed between an existing domestic or commercial boiler, to remove heat from the boiler flue gases to the extent that their temperature drops below their dew point. It has its outlet port directly above its inlet port, a canopy above the inlet port to deflect corrosive condensate into a receptacle surrounding the inlet port and a plurality of heat exchange surfaces in the form of blanked-off pipes cantilevered forwards from the rear face of the heat exchanger cavity. The zig-zag upward flow of the flue gases over the pipes tends to keep them clear of deposited soot and, in any case, the pipe surfaces are rendered accessible for cleaning by detaching the front wall of the cavity.

Cairns, S.

1985-10-16

62

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

International Nuclear Information System (INIS)

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

63

Heat transfer enhancement in cross-flow heat exchanger using vortex generator  

International Nuclear Information System (INIS)

Fouling is very serious problem in heat exchanger because it rapidly deteriorates the performance of heat exchanger. Cross-flow heat exchanger with vortex generators is developed, which enhance heat transfer and reduce fouling. In the present heat exchanger, shell and baffle are removed from the conventional shell-and-tube heat exchanger. The naphthalene sublimation technique is employed to measure the local heat transfer coefficients. The experiments are performed for single circular tube, staggered array tube bank and in-line array tube bank with and without vortex generators. Local and average Nusselt numbers of single tube and tube bank with vortex generator are investigated and compared to those of without vortex generator

64

Heat exchanger  

International Nuclear Information System (INIS)

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

65

Heat exchanger  

International Nuclear Information System (INIS)

The purpose of the invention is to construct a heat exchanger for nuclear reactors that shows no premature heating up of the secondary coolant in the feedwater pipe. According to the invention, this can be achieved by enveloping the feedwater pipe with a shielding that is attached in the pipe plates. This is done because the feedwater pipe passes through the steam chamber to establish a fluid connection with the feedwater chamber. (orig.)

66

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

67

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

Science.gov (United States)

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.

Roetzel, W.; Luo, X.

2010-11-01

68

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

International Nuclear Information System (INIS)

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

69

Heat exchanger  

International Nuclear Information System (INIS)

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

70

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

71

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

International Nuclear Information System (INIS)

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

72

Heat exchanger  

International Nuclear Information System (INIS)

This invention concerns a heat exchanger between a fluid flowing through a tube and a gas. Such an exchanger can be used, inter alia, for removing calories that cannot be used for generating electricity in a thermal or nuclear power station. This exchanger can withstand any pressure surges in the system and even the use of a high vapour pressure coolant such as ammonia, since the fluid flows in a round tube with low pressure drops (both with respect to the fluid to be cooled and the cooling air). It is rigid enough to stand up to being moved and handled as well as to gusts of wind. It is formed of units that can be handled without difficulty and that are easily dismantable and interchangeable, even in service, and it is easily maintained. The exchange area is high for a minimum frontal area and this enables the size of the supporting frame to be reduced and makes it easy to hide it behind a screen of trees should this prove necessary. Finally, it is composed of a small number of standard units thus reducing the industrial production cost. These units are rectangular plates, each one being a flat tubular coil fitted between two flat parallel sheet metal plates having on their outer sides flat top raised bosses. These units are assembled together by the tops of the bosses so as to form an exchanger bank, each bank comprising two collectors to which the bank coils are tightly connected

73

Heat exchanger  

International Nuclear Information System (INIS)

The construction of this heat exchanger will avoid the disadvantages of the conventional constructions, which are listed in detail, in particular with regard to material and space requirements. The heat exchanger, which is especially suitable for gas-cooled reactors, consists of a number of similar elements, preferably with rectangular configurations, arranged side by side. These elements in the shape of boxes which are open top and bottom have the gaseous cooling medium flowing through them which transfers the reactor heat to the pipe coils lying at right angles to the flow direction. These elements are installed for this below the cove of the reactor in the downward current of the cooling medium. Between the sides of the vertically situated elements there are extension gaps for the absorption of heat expansion over the whole height. According to invention these extension gaps contain blocking elements on several levels and openings in the sides of the elements which create a gap. Graded pressure reduction of the first medium is achieved by means of the thus created chambers and canals over the height of the elements avoiding an otherwise necessary strengthening of the element walls. A better balance of temperature inside the elements is also brought about by means of the partial cross current of the cooling gas. (HP)

74

Heat exchangers  

International Nuclear Information System (INIS)

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

75

Corrosive resistant heat exchanger  

Science.gov (United States)

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

Richlen, Scott L. (Annandale, VA)

1989-01-01

76

Life Cycle Cost Model for Condition Monitoring of heat exchanger  

OpenAIRE

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

77

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

78

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 procedure used was to obtain experimental performance data from a solar system using a DCLLHE for both heating and cooling functions, develop a simulation model for the system, validate the model using the data, apply the model in five different climatic regions of the country for a complete year, and estimate the life-cycle cost of the system for each application. The results are compared to a conventional solar system, using a standard shell-and-tube heat exchanger.

Karaki, S.; Brothers, P.

1980-06-01

79

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

80

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

81

Online performance assessment of heat exchanger using artificial neural networks  

Directory of Open Access Journals (Sweden)

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

C. Ahilan, S. Kumanan, N. Sivakumaran

2011-09-01

82

Materials experience and selection for nuclear materials production reactor heat exchangers  

International Nuclear Information System (INIS)

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

83

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

84

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)

85

Development of VB Based Software For Design And Analysis of Heat Exchangers  

Directory of Open Access Journals (Sweden)

Full Text Available The exchange of heat is one of the most important processes in the mechanical industry and heat exchanger is the major equipment used to transfer heat from one medium to another. This project work on the Computer Aided Design (CAD of shell and tube, double pipe and spiral coil heat exchanger aims to provide an easy way to design it. A case study question was taken and all the necessary calculations in the thermal design are carried out using standard method of heat exchanger design. The thermal design is then used as a guide to the computer aided design using computer codes. The computer software program used is the Visual Basic called Visual Basic 6.0 (VB 6 because of its numerous advantages over the other software programmes. The result gotten from the computer aided design was compared to the result from the thermal design. The computer aided design software was equally used to test other problems on shell and tube, double pipe and spiral coil heat exchanger. Because the computer aided design was found to be more accurate, quicker and more efficient, it was recommended for use in companies and industries.

Prof. Sandeep M. Joshi

2014-07-01

86

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

Directory of Open Access Journals (Sweden)

Full Text Available Exhaust Gas Recirculation (EGR technique using EGR cooler reduces the NOx content from the tailpipe emission of Diesel engines. Commercial computational fluid dynamics (CFD code is used to solve and simulate the flow-fields and temperature distribution of fluids inside the EGR cooler. In this investigation two models (model-a and model-b of EGR coolers are developed using Pro/Engineer Wildfire 4.0 software. Model-a is a single pass baffled shell and tube heat exchanger with staggered tube arrangement of plain tubes and having conical shaped stationary heads (gas inlet/outlet chamber [2]. Model-b is having the same tube arrangement and spacing as they were in model-a, but the plain tubes were replaced with internally finned tubes to increase the internal surface area of tubes. The finned tubes are of same outer diameter and same tube material as that of plain tubes. In model-a and model-b, the inlet conditions of both the cooling water and hot gases are the same. These models are analysed with Ansys Fluent 13.0 software. The CFD results show that, by replacing the plain tubes with internally finned tubes, the rate of heat exchange between the cooling water and hot gases enhanced.

Ibrahim Hussain Shah

2014-08-01

87

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

88

Applicability of plate heat exchanger to plant cooling water systems in pressure water reactor  

International Nuclear Information System (INIS)

Advanced Pressurized Reactor 1400(APR 1400), which is a standard evolutionary Advanced Light Water Reactor(ALWR), has been developed from 1992 as one of long-term government project(G-7). The APR-1400 is designed to operate at the rated output of 4000MWt to produce an electric power output of around 1450MWe. Due to the increased electric power, in nuclear power plant huge quantities of heat are generated in the thermo-dynamic process used for producing electrical energy. So, there is considerately additional cooling, heat transfer area and increased cooling water of heat exchanger which take care of the different smaller cooling duties within the nuclear power plant. We review applying to PHE instead of shell-and tube heat exchanger. In this paper, we describe the major design features of PHE, comparison between a PHE and a shell-and-tube heat exchanger, and then applicability of plate heat exchanger in nuclear power plant component cooling water systems

89

The use of compact heat exchangers in heat-integrated distillation columns  

Energy Technology Data Exchange (ETDEWEB)

The Heat-Integrated Distillation Column (HIDiC), in which heat is transferred directly from the rectification section to the stripping section of the column, has a much higher energy efficiency than either a normal distillation column or a vapour-recompression column. Although the HIDiC concept has been researched for a number of years, it has not yet been commercialised. Recent literature describes an embodiment of the concept, which resembles a shell-and-tube heat exchanger. However an alternative embodiment based on a compact (plate) heat exchanger has several potential advantages over the shell-and-tube design. These advantages include compactness, a closer temperature approach, modular structure, and flexibility in design. In order to investigate the feasibility of a HIDiC design based on a plate-fin heat exchanger, a computer program has been developed. This approach is based on an existing model for conventional distillation, coupled to a spreadsheet program that incorporates correlations for such factors as flooding, wetting, and fin efficiency, and that takes account of geometric constraints in the plate-fin design. The software was applied in a preliminary case study for a propane-propene splitter. This confirmed the scope for energy savings, with energy savings of about 37% compared to a vapour-recompression column. First indications suggest that the economics may also be favourable. It was concluded that the plate-fin design is feasible in principle. However the required hydraulic diameter was larger than currently available in commercial plate-fin heat exchangers.

Hugill, J.A.; Van Dorst, E.M. [ECN Energy Efficiency in the Industry, Petten (Netherlands)

2005-09-01

90

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

91

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

Science.gov (United States)

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

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

2003-05-01

92

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

93

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.

94

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

Energy Technology Data Exchange (ETDEWEB)

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

Chang H. Oh; Eung S. Kim

2008-09-01

95

Energy-efficiency comparison of advanced ammonia heat-exchanger types  

Energy Technology Data Exchange (ETDEWEB)

Ammonia is the most cost-effective working fluid for many Rankine power cycles and is widely utilized in industrial refrigeration applications. For example, it was selected as the most advantageous working fluid for the comprehensive closed-cycle Ocean Thermal Energy Conversion investigations where the heat source and sink are the warm, surface seawater and the cold, deep seawater, respectively. An essential part of this investigation was to measure the performance of many advanced heat-exchanger types using ammonia as the working fluid and to compare these results with those for conventional shell-and-tube designs. This paper presents an overview of these experiments and their potential significance for improved energy efficiency for industrial refrigeration applications. The heat exchangers used for industrial refrigeration systems account for about 50% of the equipment cost. However, current practice is to use state-of-the-art designs -- the shell-and-tube type without enhanced tubes. Substantial energy savings are possible through the use of advanced ammonia evaporator and condenser heat-exchanger types. 31 refs., 10 figs., 6 tabs.

Panchal, C.; Rabas, T.

1990-01-01

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

Performance of PCCS with horizontal U-tube type heat exchanger  

International Nuclear Information System (INIS)

The passive containment cooling system (PCCS) using a shell-and-tube type heat exchanger has been developed as a decay heat removal system following a severe accident. It requires no active devices and no operator action to start and maintain its function. A horizontal heat exchanger has been studied for the PCCS heat exchanger since it has several advantages over a vertical large diameter tube heat exchanger that was originally proposed for the SBWR. The fundamental heat removal performance and pressure loss characteristics has been investigated by conducting a thermal-hydraulic test using single horizontal U-shape heat exchanger tube. Comparing with the experimental results, the analysis model has been adopted for estimating the heat transfer performance and the pressure loss of a PCCS horizontal heat exchanger. The analysis model was applied to the sizing of the PCCS horizontal heat exchanger for the next generation BWR. The effect of heat transfer tube diameter and length on the PCCS performance has been estimated. According to the analysis results, the economical benefits of the horizontal heat exchanger type PCCS over the original vertical heat exchanger have been clarified. (author)

98

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

International Nuclear Information System (INIS)

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

99

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

Science.gov (United States)

...2010-10-01 2010-10-01 false Patches in shells and tube sheets. 59.10-20 Section...Service § 59.10-20 Patches in shells and tube sheets. (a) Unreinforced openings in the shells or drums of boilers or pressure...

2010-10-01

100

Heat exchange apparatus  

International Nuclear Information System (INIS)

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

101

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

102

Optimization of Heat Exchangers  

Energy Technology Data Exchange (ETDEWEB)

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

Ivan Catton

2010-10-01

103

Electrostatic enhancement of heat transfer in gas-to-gas heat exchangers  

Science.gov (United States)

Basic study of electrohydrodynamic (EHD) enhancement of heat transfer in heat exchangers was the subject of an investigation. The author's efforts over the three-year project time period can be categorized into three consecutive phases. In phase 1, EHD heat transfer enhancements and pressure drop characteristics for conventional pipe flows as a function of electric field potential, field polarity, number of electrodes (single or double configuration), and flow regime (Reynolds number ranging from fully laminar to fully turbulent conditions) were studied. Study of heat transfer enhancements and pressure drop characteristics in a shell-and-tube, gas-to-gas heat exchanger were performed in Phase 2 of the project. To address the applicability of the EHD technique under operating conditions of gas-fired equipment, the role of various working fluid properties were studied in Phase 3 of the project. Specifically, effects of working fluid humidity, temperature, pressure, and impurity level on the magnitude and nature of the EHD heat transfer enhancements were studied. A maximum of 322 percent heat transfer enhancement with only 112 percent increase in pressure drops was achieved under simultaneous excitation of the tube and shell sides of the heat exchanger in the study. With optimized electric and flow field parameters, much higher enhancements can be expected.

Ohadi, M. M.

1991-06-01

104

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

International Nuclear Information System (INIS)

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

105

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

106

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

107

Nuclear heat exchangers  

International Nuclear Information System (INIS)

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

108

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

109

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

2011-06-28

110

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)

111

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)

112

Modular Heat Exchanger With Integral Heat Pipe  

Science.gov (United States)

Modular heat exchanger with integral heat pipe transports heat from source to Stirling engine. Alternative to heat exchangers depending on integrities of thousands of brazed joints, contains only 40 brazed tubes.

Schreiber, Jeffrey G.

1992-01-01

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

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

115

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

116

Simulation of shell-tube and heat exchangers: film coefficients. Simulacion de intercambiadores de carcasa y tubos: coeficientes de pelicula  

Energy Technology Data Exchange (ETDEWEB)

The heat transfer of process fluids is a main part of them and the interchanges of shell and tubes are used in these applications. This study presents coefficients calculation of film and heat losses. (Author) 3 refs.

Inostraza Hoffmann, X.E.; Pares Perez, J.A.

1993-01-01

117

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

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

119

Radial flow heat exchanger  

Science.gov (United States)

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

Valenzuela, Javier (Hanover, NH)

2001-01-01

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)

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

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-09-15

123

Tube vibration in industrial size test heat exchanger  

International Nuclear Information System (INIS)

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

124

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

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 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

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 4A was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the identified tube. The leaking tube was removed and examined metallurgically to determine the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summary herein

127

Heat exchanger restart evaluation  

Energy Technology Data Exchange (ETDEWEB)

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.

Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

1992-02-28

128

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

129

Modular heat exchanger  

International Nuclear Information System (INIS)

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

130

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

131

Heat exchanger materials  

International Nuclear Information System (INIS)

This chapter reviews recent research into corrosion mechanisms and suggests potential remedies for PWR steam generators. The key aspects of the data base assembled in support of the reference LMFBR steam generator and IHX are summarized. The author reviews early field experience and discusses the development of alternative or advanced LMFBR heat exchanger materials, reviews corrosion problems in condensers (exclusively LWR) and searches for improved tubing materials. Typical designs and materials of construction for these heat exchanger components are described and the modifications to conventional designs necessitated by the emerging CTR concepts are also included

132

Tube boiler heat exchanger  

International Nuclear Information System (INIS)

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

133

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

Science.gov (United States)

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

Lotfi, Babak; Wang, Qiuwang

2013-07-01

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

New welding method for tubes and tube plates of heat exchangers for FBRs  

International Nuclear Information System (INIS)

The cooling systems for FBRs comprise the intermediate heat exchanger for exchanging heat between primary sodium and secondary sodium and the steam generator for exchanging heat between the secondary sodium and water. The intermediate heat exchanger is that of shell and tube type, and it becomes large as the reactor proceeds to a demonstration reactor and a commercial reactor. Accordingly, the number of heat transfer tubes and the size of tube plates increase, and the welding method for tubes and tube plates to obtain the high reliability of welded parts and to achieve low cost and short delivery is required. For this purpose, the method of inserting heat transfer tubes into tube plates by same dimension as their wall thickness and welding them by automatic TIG method so as to attain perfect penetration was developed. In order to confirm the reliability of the welded joints by this method, the test for evaluating the short time and long term strength was carried out. As the result, it was confirmed that the satisfactory performance of the welded joints was able to be obtained, and this method can be applied to actual heat exchangers. Besides, non-destructive inspection technique required for the development of this welding method was developed. The determination of welding torch position and the improvement of welding efficiency are being studied. (Kako, I.)

136

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

137

Analysis of loss-of-flow transients in the intermediate heat exchanger using the COMMIX code  

International Nuclear Information System (INIS)

The intermediate heat exchanger (IHX) is an important component of the liquid-metal fast breeder reactor (LMFBR). It plays a very important role in the safe and reliable operation of a nuclear plant. Evaluation of thermal-hydraulic conditions are important in the design and development of a reliable and economical heat exchanger. These evaluations would provide complete maps of the temperature field of both the working fluids and the heat transfer tube. The maps are used for a large range of operating conditions, including nominal as well as off-nominal. Knowledge of temperature and flow distribution in both the shell and the tube side will ensure that the unit will meet its thermal performance requirements. Moreover, information is needed to provide proper evaluation of the thermal performance characteristics of a heat exchanger under the natural circulation conditions that result from a loss of coolant. The flow pattern and the thermal map of a shell-and-tube heat exchanger may be obtained either through actual testing of a scale model or by using analytical methods. To provide these evaluations multidimensional thermal-hydraulic codes are assessed for heat exchanger applications. The purpose of this paper is to present the thermal performance evaluation of the IHX of the Fast Flux Test Facility (FFTF) during a loss-of-coolant transient using the COMMIX-1B code and to compare the results with experimental data

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

139

Process heat transfer principles, applications and rules of thumb  

CERN Document Server

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

140

Manufacture of heat exchangers  

International Nuclear Information System (INIS)

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

141

Tubed heat exchanger  

International Nuclear Information System (INIS)

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

142

Membrane Based Heat Exchanger  

OpenAIRE

Reduction of the energy used to acclimatise buildings is a huge challenge simultaneously with the implementation of air tight low energy buildings. In residential buildings with several living units centralised air handling units are the most energy efficient system. However, in a centralised system there is important to avoid leakages of pollutions between the exhaust air and the supply air. This leads to that flat plate heat exchangers are used instead of the more energy efficient rotary he...

Aarnes, Sofie Marie

2012-01-01

143

Mathematical programming model for heat exchanger design through optimization of partial objectives  

International Nuclear Information System (INIS)

Highlights: • Rigorous design of shell-and-tube heat exchangers according to TEMA standards. • Division of the problem into sets of equations that are easier to solve. • Selected heuristic objective functions based on the physical behavior of the problem. • Sequential optimization approach to avoid solutions stuck in local minimum. • The results obtained with this model improved the values reported in the literature. - Abstract: Mathematical programming can be used for the optimal design of shell-and-tube heat exchangers (STHEs). This paper proposes a mixed integer non-linear programming (MINLP) model for the design of STHEs, following rigorously the standards of the Tubular Exchanger Manufacturers Association (TEMA). Bell–Delaware Method is used for the shell-side calculations. This approach produces a large and non-convex model that cannot be solved to global optimality with the current state of the art solvers. Notwithstanding, it is proposed to perform a sequential optimization approach of partial objective targets through the division of the problem into sets of related equations that are easier to solve. For each one of these problems a heuristic objective function is selected based on the physical behavior of the problem. The global optimal solution of the original problem cannot be ensured even in the case in which each of the sub-problems is solved to global optimality, but at least a very good solution is always guaranteed. Three cases extracted from the literature were studied. The results showed that in all cases the values obtained using the proposed MINLP model containing multiple objective functions improved the values presented in the literature

144

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 d, 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.

145

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

146

A dynamic model of a shell-and-tube condenser operating in a vapour compression refrigeration plant  

Energy Technology Data Exchange (ETDEWEB)

This work presents a mathematical model of a shell-and-tube condenser based on mass continuity, energy conservation and heat transfer physical fundamentals, whose methodology can be easily adapted for modelling any type of condenser. The model is formulated as a combination of control volumes that represents all the refrigerant states in the condenser and the liquid receiver function, which is carried out by the condenser of the experimental plant. Model validation is performed by using steady-state data and transient tests from an experimental vapour compression plant; the prediction error of the model is lower than 5% and a good representation of the dynamic performance of the condenser is achieved. A theoretical comparison involving the importance of the dynamic responses of the evaporator and the condenser at the plant is also presented. (author)

Llopis, R.; Cabello, R. [Dept. of Mechanical Engineering and Construction, Campus de Riu Sec, Jaume I Univ., E-12071 Castellon (Spain); Torrella, E. [Dept. of Applied Thermodynamics, Camino de Vera 14, Polytechnic Univ. of Valencia, E-46022 Valencia (Spain)

2008-07-15

147

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

International Nuclear Information System (INIS)

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

148

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

International Nuclear Information System (INIS)

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

149

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

International Nuclear Information System (INIS)

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

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

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

152

The Design of Heat Exchangers  

OpenAIRE

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

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

2011-01-01

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

154

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

155

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

156

The heat pipe exchanger with controllable heat exchanging area  

Science.gov (United States)

The heat transfer rate through the heat exchanger in an industrial boiler that burns heavy oils must be controlled so as not to decrease the exhaust gas temperature below the dew point of sulfuric acid. Two systems of heat pipe exchangers are examined: one controls the heat exchange area of the condenser section of the heat pipes and the other uses the variable conductance heat pipes. The characteristics of these two systems are described. The temperatures at various points and the gas quantity are plotted against the boiler loads. The maintainability and operational reliability of both systems are demonstrated.

Oshiro, M.; Takasu, S.; Kurihara, M.; Taneda, K.; Nakamoto, T.; Nakayama, H.

1984-03-01

157

Oscillating-Coolant Heat Exchanger  

Science.gov (United States)

Devices useful in situations in which heat pipes inadequate. Conceptual oscillating-coolant heat exchanger (OCHEX) transports heat from its hotter portions to cooler portions. Heat transported by oscillation of single-phase fluid, called primary coolant, in coolant passages. No time-averaged flow in tubes, so either heat removed from end reservoirs on every cycle or heat removed indirectly by cooling sides of channels with another coolant. Devices include leading-edge cooling devices in hypersonic aircraft and "frost-free" heat exchangers. Also used in any situation in which heat pipe used and in other situations in which heat pipes not usable.

Scotti, Stephen J.; Blosser, Max L.; Camarda, Charles J.

1992-01-01

158

Matrix-type heat exchangers  

Science.gov (United States)

Problems related to the analysis, design, and fabrication of compact matrix-type heat exchangers are discussed. Particular attention is given to the general characteristics describing the intensity of heat transfer and the hydrodynamic resistance of the matrices, an analysis of the efficiency of perforated ribs, and an evaluation of the efficiency of the matrix heat exchange surfaces. The effect of longitudinal heat conduction on heat transfer in the heat exchanger is examined, and a method is proposed whereby this factor can be allowed for in the analysis.

Mikulin, E. I.; Shevich, Iu. A.

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

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

161

Heat exchanger bypass test report  

International Nuclear Information System (INIS)

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

162

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

163

Heat exchanger repair  

International Nuclear Information System (INIS)

There are two ways to rapir heater tubes in tubular heat exchangers, partial replacement of tubes and a technique called sleeving. In the former case, the defective tube section is cut out, removed, and replaced by a new section butt welded to the old piece of tube which remained in place. In the sleeving technique, a tube sleeve is slid into the defective tube and, after expansion, welded to the original tube. In this case, the welding technique employed is not laser welding, as is often maintained in the literature, but TIG pulsation welding. The results of preliminary tests and the qualification of both processes are outlined in the article; an account is given also of the replacement of the tube sections when repairing condensate coolers. (orig.)

164

Regenerative heat exchangers. Regeneratiivinen kuulalaemmoensiirrin  

Energy Technology Data Exchange (ETDEWEB)

The aim of this research was to develop a computer program that could be used for simulating heat transfer and pressure drop in a regenerative particle heat exchanger for gases. Particles were considered spherical. Two cases were studied, counterflow- and crossbow heat exchangers. Heat transfer by conduction and radiation were considered small compared to heat transfer by forced convection. The convection heat transfer coefficient and pressure drop are calculated by using empirical correlations developed for packed beds. In the program there is a possibility to choose different correlations in different cases. The heat transfer equation in spherical coordinates is discretized by using implicit difference method and solved by the matrix inversion method. (orig.)

Vaittinen, P.

1998-01-01

165

Regenerative heat exchangers; Regeneratiivinen kuulalaemmoensiirrin  

Energy Technology Data Exchange (ETDEWEB)

The aim of this research was to develop a computer program that could be used for simulating heat transfer and pressure drop in a regenerative particle heat exchanger for gases. Particles were considered spherical. Two cases were studied, counterflow- and crossbow heat exchangers. Heat transfer by conduction and radiation were considered small compared to heat transfer by forced convection. The convection heat transfer coefficient and pressure drop are calculated by using empirical correlations developed for packed beds. In the program there is a possibility to choose different correlations in different cases. The heat transfer equation in spherical coordinates is discretized by using implicit difference method and solved by the matrix inversion method. (orig.)

Vaittinen, P.

1998-12-31

166

Experimental research on heat transfer in a coupled heat exchanger  

OpenAIRE

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

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

2013-01-01

167

Heat pipes in modern heat exchangers  

International Nuclear Information System (INIS)

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

168

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

Scientific Electronic Library Online (English)

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

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

2014-08-01

169

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

170

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

171

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.

172

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

173

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' (TOIRe 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.

174

WASTE HEAT RECOVERY FROM BOILER OF LARGE-SCALE TEXTILE INDUSTRY  

OpenAIRE

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...

Prateep Pattanapunt; Kanokorn Hussaro; Tika Bunnakand; Sombat Teekasap

2013-01-01

175

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-12-31

176

Materials for gasifier heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

Gasification systems were originally developed to be fired on coal, but there is now interest in co-firing coal with waste or biomass or using low-grade coals and heavy fuel oils in order to reduce environmental impact and fuel costs. All gasification technologies require a heat exchanger between the gasifier and the gas cleaning system. However, gasifier hot gas path environments are potentially very aggressive for materials both during plant operation and downtime periods. The potential corrosive effects of deposits formed on coal-fired and co-fired gasifier heat exchangers in ABGC and IGCC systems have been assessed. Data on the formation of deposits on gasifier heat exchangers have been gathered and a literature survey of downtime corrosion testing relating to gasifier heat exchangers carried out. Laboratory studies have been carried out to investigate the potential response of current and candidate gasifier heat exchanger materials (such as Alloy 800 and Sanicro 28) to such deposits. Electrochemical tests in aqueous solutions are being used to give a ranking of the materials in typical environments anticipated for ABGC and IGCC heat exchangers. A modified EPRI downtime corrosion test has been employed which involves exposing candidate materials covered with a simulated deposit to a humid atmosphere. Preliminary results from baseline tests are given. This work is leading towards the identification of combinations of fuels, operating conditions and materials that could produce rapid heat exchanger failures due to interactions with the deposits formed during operation. (orig.)

Kilgallon, P.; Simms, N.J.; Norton, J.F.; Oakey, J.E. [Power Generation Technology Centre, Cranfield Univ. (United Kingdom)

2002-07-01

177

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 Targemmercially 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

178

New general correlations for pure chevron plate heat exchangers. Paper no. IGEC-1-069  

International Nuclear Information System (INIS)

There is an increase interest in the development of Plate Heat Exchanger (PHE) as effective and compact heat transfer equipment. It exhibits excellent heat transfer characteristics which allow more compact designs than that achieved with conventional shell and tube heat exchangers. This paper proposes new Modified Leveque Equations (MGLEs) which were originally based on Generalized Leveque Equation (GLE) presented by Martin, 1996, for mixed chevron plates. A comparative study was conducted to evaluate the thermal performance calculations of MGLEs and recently developed complex equation presented by Muley and Manglik, 1999, against the well known correlations for pure chevron angles presented by Kumar, 1984. An industrial case study was used to carry out the required analysis and comparison. The complex equation of Muley and Manglik,1999, gave noticeable deviation error in angles of 30o , 40o and 50o when compared with classical correlations for pure chevron plates. Whereas the two equations of the MGLEs based on hard plate, MGLE(1), and soft plate, MGLE(2) gave an excellent overall performance and they can with confidence replace the Kumar's correlations for pure chevron angles at wide range of Reynolds numbers from laminar to high turbulent regions. (author)

179

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

180

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

181

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

182

Group of modular heat exchangers  

International Nuclear Information System (INIS)

In modular heat exchangers, undesirable stresses may occur in various parts of the installation because of differences in temperature. The purpose of the invention is to obviate these stresses by connecting at least the feedwater pipes of the heat exchangers with the feedwater distributor by means of spiral pipes. By the spiral construction of the pipes, they may more easily expand and contract under temperature changes. (Auth.)

183

Tube in shell heat exchangers  

International Nuclear Information System (INIS)

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

184

Materials for gasifier heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

The project has assessed the potential corrosive effects of deposits formed on coal-fired and coal/waste co-fired gasifier fuel-gas/syngas heat exchangers in ABGC and IGCC systems. This has included determining the ranges of deposit compositions formed on heat exchangers with different fuels and quantitatively assessing the effects of such deposits on downtime corrosion (including the effects of potential preventative measures) and synergistic interactions. These activities have lead to the identification of combinations of fuels, operating conditions and materials that could produce rapid heat exchanger failures due to interactions with the deposits formed during the heat exchanger operation. The following candidate gasifier heat exchanger alloys were investigated: AISI 316L, AISI 310, AISI 347H, Alloy 800, Sanicro 28, Haynes 160, Esshete 1250, Haynes 556, IN625, and T23. In terms of cost and performance Sanicro 28 appears to be the best choice for evaporative heat exchangers in the range of test conditions investigated. 48 refs., 59 figs., 28 tabs.

Kilgallon, P.; Simms, N.J.; Oakey, J.E. [Cranfield University, Cranfield (United Kingdom). Power Generation Technology Centre

2004-11-01

185

Non-linear creep fatigue analysis of a sodium heat exchanger component for the fast flux test facility  

International Nuclear Information System (INIS)

The heat exchanger is a counter-flow shell and tube type, constructed of 304 austenitic stainless steel. It is postulated that some 800 operating transients will occur during the service life of the plant. A detailed elastic-plastic-creep analysis was made of the primary inlet nozzle, to ascertain whether or not the inelastic deformation and creep-fatigue damage are within the allowable limits. The objective of the paper is to show how the currently available analytical methods in plasticity and creep are applied in a typical high temperature design environment in order to design the nozzle. The results of a detailed analysis in which the finite element method was used are compared with the results of simplified analysis procedures. (author)

186

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

187

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-01-15

188

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

International Nuclear Information System (INIS)

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

189

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

190

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

International Nuclear Information System (INIS)

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

191

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

International Nuclear Information System (INIS)

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

192

Optimal Pin Fin Heat Exchanger Surface  

OpenAIRE

This research presents the results of numerical study of heat transfer and pressure drop in a heat exchanger that is designed with different shape pin fins. The heat exchanger used for this research consists of a rectangular duct fitted with different shape pin fins, and is heated from the lower plate. The pin shape and the compact heat exchanger (CHE) configuration were numerically studied to maximize the heat transfer and minimize the pressure drop across the heat exchanger. A three dimensi...

Nabati, Hamid

2008-01-01

193

Planning heat exchange systems  

International Nuclear Information System (INIS)

Following a discussion on heating or cooling media, the possible faults arising when not keeping to the required technical specifications are firstly indicated. The soiling and cleaning, vibration and selection of material are discussed, as well as preventive planning measures recommended to avoid later trouble. Finally, some practical tips are given which should not be overlooked. (orig./HP)

194

Membrane and plastic heat exchangers performance  

OpenAIRE

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...

Masud Behnia; Mohammad Shakir Nasif; Morrison, Graham L.

2005-01-01

195

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)

196

Influence of Ship Vibrations on Heat Exchangers  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of vibrations on heat transfer has been described. The study made on a double pipe counterflow heat exchanger clearly shows that vibrations of heat exchnagers cause increase in heat transfer coefficients. The maximum increase in overall heat transfer coefficient achieved is 165%. In places where vibrations are inherently present like in ships, the onboard heat exchangers can make use of this phenomenon and increase the effectiveness of heat exchangers.

H.S.N. Sastry

2014-03-01

197

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

198

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

199

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

200

Heat exchanger with oscillating flow  

Science.gov (United States)

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

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

1993-01-01

201

A Simulation Tool for Radiative Heat Exchangers  

OpenAIRE

In order to minimize the large fan power demand from low temperature lift heat pump systems, a radiative heat exchanger is proposed as an indoor heat exchanger design in such systems. The radiative heat exchanger utilizes both natural convection and radiation so that it is capable of reducing fan power consumption while simultaneously providing an improved thermal comfort. A software tool has been developed to simulate the operative temperature field created by a radiative heat exchanger inst...

Hwang, Yunho; Ling, Jiazhen; Radermacher, Reinhard

2012-01-01

202

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

203

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

204

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

205

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

206

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

207

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

International Nuclear Information System (INIS)

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

208

Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes  

Science.gov (United States)

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

209

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

210

Heat recovery from a cement plant with a Marnoch Heat Engine  

International Nuclear Information System (INIS)

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

211

NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger  

International Nuclear Information System (INIS)

One key long-standing issue that must be overcome to fully realize the successful growth of nuclear power is to determine other benefits of nuclear energy apart from meeting the electricity demands. The Next Generation Nuclear Plant (NGNP) will most likely be producing electricity and heat for the production of hydrogen and/or oil retrieval from oil sands and oil shale to help in our national pursuit of energy independence. For nuclear process heat to be utilized, intermediate heat exchange is required to transfer heat from the NGNP to the hydrogen plant or oil recovery field in the most efficient way possible. Development of nuclear reactor--process heat technology has intensified the interest in liquid metals as heat transfer media because of their ideal transport properties. Liquid metal heat exchangers are not new in practical applications. An important rational for considering liquid metals is the potential convective heat transfer is among the highest known. Thus explains the interest in liquid metals as coolant for intermediate heat exchange from NGNP. For process heat it is desired that, intermediate heat exchangers (IHX) transfer heat from the NGNP in the most efficient way possible. The production of electric power at higher efficiency via the Brayton Cycle, and hydrogen production, requires both heat at higher temperatures and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. Compact heat exchangers maximize t 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

212

Nondestructive inspection of the tubes of TRIGA IPR-R1 reactor heat exchanger by eddy current testing  

International Nuclear Information System (INIS)

The IPR-R1 TRIGA MARK 1 reactor is an open pool type reactor, cooled light water. It is used for research activities, personnel training and radioisotopes production, in operation since 1960 at the Nuclear Technology Development Center - CDTN/CNEN. It operates at a maximum thermal power of 100 kW and usually, the fuel cooling is done by natural circulation. If necessary, an external auxiliary cooling system, with a shell-and-tube type heat exchanger, can be used to improve the water heat removal. As part of the ageing management program of the reactor, a nondestructive evaluation of their heat exchanger stainless steel tubes will be performed, in order to verify its integrity. The examinations will be performed using the eddy current test method, which allows the detection and characterization of structural discontinuities in the wall of the tubes, if existing. For this purpose, probes and reference standards were designed and manufactured at CDTN facilities and test procedures were established and validated. In this paper, a description of the proposed infrastructure as well as the test methodology to be used in the examinations are presented and discussed. (author)

213

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

OpenAIRE

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

214

Heat exchanger for solar water heaters  

Science.gov (United States)

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

Cash, M.; Krupnick, A. C.

1977-01-01

215

Optimization of heat exchanger for indirectly heated water heater  

OpenAIRE

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

216

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

217

Rational Efficiency of a Heat Exchanger  

OpenAIRE

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 ...

Mcgovern, Jim; Smyth, Brian P.

2011-01-01

218

Modelling of Multistream LNG Heat Exchangers  

OpenAIRE

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

219

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

220

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

221

Heat exchanger for liquid metals  

International Nuclear Information System (INIS)

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

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

223

Testing and analysis of immersed heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

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

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

1986-08-01

224

Improved ceramic heat exchange material  

Science.gov (United States)

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

Mccollister, H. L.

1977-01-01

225

Comparative Study of Heat Exchangers Using CFD  

OpenAIRE

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

Melvinraj C R; Vishal Varghese C

2014-01-01

226

Heat exchangers in heavy water reactor systems  

International Nuclear Information System (INIS)

Important features of some major heat exchange components of pressurized heavy water reactors and DHRUVA research reactor are presented. Design considerations and nuclear service classifications are discussed

227

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

228

Heat transfer processes of serpentine tubular heat exchangers  

OpenAIRE

The focus of the research described herein was to study the heat transfer behavior of tubular serpentine heat exchangers commonly used in residential non-condensing furnaces. The main task was to develop a computer model of the furnace heat exchanger that accurately simulates furnace performance. The purpose of the model is to provide design engineers a tool that can predict performance trends for given design changes. Many of the relevant heat transport processes found within these heat exch...

Harris, Daniel Kevin

1997-01-01

229

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

OpenAIRE

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

230

Plate heat exchangers design, applications and performance  

CERN Document Server

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

231

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

232

Optimization of parameters of heat exchangers vehicles  

Directory of Open Access Journals (Sweden)

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

Andrei MELEKHIN

2014-09-01

233

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

234

Cryogenic fluid flow instabilities in heat exchangers  

Science.gov (United States)

Analytical and experimental investigation determines the nature of oscillations and instabilities that occur in the flow of two-phase cryogenic fluids at both subcritical and supercritical pressures in heat exchangers. Test results with varying system parameters suggest certain design approaches with regard to heat exchanger geometry.

Fleming, R. B.; Staub, F. W.

1969-01-01

235

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

OpenAIRE

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...

Malkin E. C.; Nikolaenko Yu. E.; Djachkov M. I.; Yu, Nikolaienko T.

2010-01-01

236

Cryogenic heat exchanger with turbulent flows  

International Nuclear Information System (INIS)

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

237

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

238

High temperature alloys and ceramic heat exchanger  

International Nuclear Information System (INIS)

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

239

Testing and plugging power plant heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1994-12-31

240

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.

241

Heat transfer in SiC compact heat exchanger  

International Nuclear Information System (INIS)

For development of a compact SiC heat exchanger, numerical heat transfer analysis was conducted to investigate its performance for a wide range of thermal media, liquid LiPb and helium gas, flow rates. The numerical model used was based on the heat exchanger test module developed by the authors. Within the authors' experimental range, the heat quantity transferred from high temperature liquid LiPb to helium gas and the overall heat transfer coefficients obtained numerically are in agreement with the experimental results. Therefore, the numerical model has proved to be valid for estimation of heat transfer phenomena in the heat exchanger in incompressible regime. The heat quantity transferred from LiPb to He amounts up to 3.7 kW at helium pressure of 0.5 MPa. On the basis of the numerical results, a correlation for helium forced convection heat transfer in the heat exchanger is presented, which describes numerical results with an error of 1%. For heat transfer in LiPb, the Nusselt numbers calculated from an existing correlation for liquid metal heat transfer agree well with the present numerical results. The heat transfer of LiPb in the SiC compact heat exchanger would possibly be predicted from the conventional correlations based on the studies of liquid metal convective heat transfer. A concept of SiC compact heat exchanger studied could be applied to a design of intermediate heat exchangers operating at high temperatures in fusion reactor, as well as HTTR and VHTR sfusion reactor, as well as HTTR and VHTR systems.

242

Heat transfer in SiC compact heat exchanger  

Energy Technology Data Exchange (ETDEWEB)

For development of a compact SiC heat exchanger, numerical heat transfer analysis was conducted to investigate its performance for a wide range of thermal media, liquid LiPb and helium gas, flow rates. The numerical model used was based on the heat exchanger test module developed by the authors. Within the authors' experimental range, the heat quantity transferred from high temperature liquid LiPb to helium gas and the overall heat transfer coefficients obtained numerically are in agreement with the experimental results. Therefore, the numerical model has proved to be valid for estimation of heat transfer phenomena in the heat exchanger in incompressible regime. The heat quantity transferred from LiPb to He amounts up to 3.7 kW at helium pressure of 0.5 MPa. On the basis of the numerical results, a correlation for helium forced convection heat transfer in the heat exchanger is presented, which describes numerical results with an error of 1%. For heat transfer in LiPb, the Nusselt numbers calculated from an existing correlation for liquid metal heat transfer agree well with the present numerical results. The heat transfer of LiPb in the SiC compact heat exchanger would possibly be predicted from the conventional correlations based on the studies of liquid metal convective heat transfer. A concept of SiC compact heat exchanger studied could be applied to a design of intermediate heat exchangers operating at high temperatures in fusion reactor, as well as HTTR and VHTR systems.

Takeuchi, Y., E-mail: y-takeuchi@iae.kyoto-u.ac.jp [Institute of Advanced Energy, Kyoto University, Gokasho Uji, Kyoto 611-0011 (Japan); Park, C. [Institute of Advanced Energy, Kyoto University, Gokasho Uji, Kyoto 611-0011 (Japan); Noborio, K. [Institute of Sustainability Science, Kyoto University, Gokasho Uji, Kyoto 611-0011 (Japan); Yamamoto, Y.; Konishi, S. [Institute of Advanced Energy, Kyoto University, Gokasho Uji, Kyoto 611-0011 (Japan)

2010-12-15

243

Heat exchanger device and method for heat removal or transfer  

Science.gov (United States)

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

Koplow, Jeffrey P

2013-12-10

244

Improved ceramic heat exchanger materials  

Science.gov (United States)

The development and evaluation of materials for potential application as heat exchanger structures in automotive gas turbine engines is discussed. Test specimens in the form of small monolithic bars were evaluated for thermal expansion and dimensional stability before and after exposure to sea salt and sulfuric acid, followed by short and long term cycling at temperatures up to 1200 C. The material finally selected, GE-7808, consists of the oxides, ZrO2-MgO-Al2O3-S1O2, and is described generically as ZrMAS. The original version was based on a commercially available cordierite (MAS) frit. However, a clay/talc mixture was demonstrated to be a satisfactory very low cost source of the cordierite (MAS) phase. Several full size honeycomb regenerator cores, about 10.2 cm thick and 55 cm diameter were fabricated from both the frit and mineral versions of GE-7808. The honeycomb cells in these cores had rectangular dimensions of about 0.5 mm x 2.5 mm and a wall thickness of approximately 0.2 mm. The test data show that GE-7808 is significantly more stable at 1100 C in the presence of sodium than the aluminosilicate reference materials. In addition, thermal exposure up to 1100 C, with and without sodium present, results in essentially no change in thermal expansion of GE-7808.

Rauch, H. W.

1980-01-01

245

Heat exchanger, head and shell acceptance criteria  

Energy Technology Data Exchange (ETDEWEB)

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

Lam, P.S.; Sindelar, R.L.

1992-09-01

246

Heat exchanger, head and shell acceptance criteria  

International Nuclear Information System (INIS)

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

247

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.)

248

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

249

40 CFR 63.1435 - Heat exchanger provisions.  

Science.gov (United States)

...2010-07-01 2010-07-01 true Heat exchanger provisions. 63.1435 Section...Polyols Production § 63.1435 Heat exchanger provisions. (a) The owner...requirements of § 63.104 for heat exchange systems, with the...

2010-07-01

250

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

251

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

252

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

253

Decay heat removal by sodium-air heat exchangers  

International Nuclear Information System (INIS)

In fast reactors, decay heat is removed by special sodium circuits equipped with a sodium-sodium heat exchanger immersed in the hot pool and with a sodium-air heat exchanger. Studies carried out by the Ansaldo company in association with ENEA have shown that both the sodium and the air circuits can have natural circulation. This option, however, requires the circuit components to be specially designed in order to cope with the large thermal gradients which occur and to ensure that natural circulation begins and is satisfactorily maintained without risk of sodium solidification. The Belleli company has made a decisive contribution to these results by constructing the sodium-air heat exchangers for the ultimate heat sink circuit of the Creys-Malville plant and four heat exchangers for the PEC reactor. (author)

254

Heat Exchanger Support Bracket Design Calculations  

Energy Technology Data Exchange (ETDEWEB)

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

Rucinski, Russ; /Fermilab

1995-01-12

255

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

256

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

OpenAIRE

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

257

SAFE Reactor Brayton Cycle Primary Heat Exchangers  

International Nuclear Information System (INIS)

Gas cooling of power-dense nuclear reactor cores can produce large thermal and stress gradients through sensible temperature changes in the coolant. In-core heat pipes remove heat isothermally and reduce the severity of these gradients. The modular SAFE reactor concept consists of numerous heat pipes that permit core re-assembly during test and preflight integration. The redundancy inherent in the modular heat pipe-based design enhances reactor reliability. The SAFE reactor is designed to operate for extended periods near full power even if several fuel pins or modules fail. 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 in preparation for the construction of a larger refractory metal version. Several promising FIGMENT stainless steel heat exchanger concepts are reviewed here. (authors)

258

Heat exchanger module for secondary circuit of nuclear heating plant  

International Nuclear Information System (INIS)

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

259

Heat exchange at supercritical pressures and the boundaries of heat exchange deterioration  

International Nuclear Information System (INIS)

One analyzed some relations for calculation of the normal heat exchange mode at upward flow of water and at supercritical pressure. One compared them with the latest experimental data. One evaluated the accuracy of the heat transfer calculation recommendations. One introduced a dependence to determine the boundary of deteriorated heat exchange generalizing data for various coolants (water, CO2, freon-12)

260

Mathematical Modeling of Spiral Heat Exchanger  

OpenAIRE

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 ...

Probal Guha, Vaishnavi Unde

2014-01-01

261

Eddy current testing of heat exchangers tubes  

International Nuclear Information System (INIS)

An automatic system for Eddy Current testing of heat exchangers tubes of warships was developed. The advantages are an exposure of the controller limited at the time required to put in place the system and a reduced time of control

262

Comparative Study of Heat Exchangers Using CFD  

Directory of Open Access Journals (Sweden)

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

Melvinraj C R

2014-05-01

263

Fatigue Testing of Heat-Exchanger Tubes  

Science.gov (United States)

Acclerated fatigue-life testing of heat-exchanger tubes simplified by technique that substitutes mechanical side load for thermally-generated axisymmetric stress. Load amplitudes adjusted to produce strains equivalent to those produced by anticipated thermal stress.

Ackerman, P.

1984-01-01

264

Heat exchangers: an energy viewpoint approach  

International Nuclear Information System (INIS)

This paper, at first, presents a brief discussion of the concept of exergy. The second part studies the exchange of heat by conduction, convection and radiation as well as the irreversibilities due to the required temperature gradient. It shows the importance of the temperature level on the heat flux and the exergy lost. This analysis results also in conclusions on the fins and the thermal insulation. The third part studies the heat exchangers, in general. The loss of exergy due to the thermal exchange permits a comparison of the thermal value of these apparatus and, as well, shows the influence of the isothermal change of state of a fluid, i.e. in vaporization. Finally, based on the conclusions reached above, different types of heat exchangers used in industrial applications are analysed

265

Tube bundle assembly for a heat exchanger  

International Nuclear Information System (INIS)

An improved type of tube bundle assembly for a heat exchanger is described which can be used as a reheater section of a vapour generator in a gas-cooled nuclear reactor. The assembly has a compact annular configuration while providing effective heat exchange capabilities, maintains minimum gas flow resistance and allows for differential expansion without the use of unheated cross-over connections. (U.K.)

266

Design concept for vessels and heat exchangers  

International Nuclear Information System (INIS)

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

267

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

268

Joule-Thomson expander and heat exchanger  

Science.gov (United States)

The Joule-Thomson Expander and Heat Exchanger Program was initiated to develop an assembly (JTX) which consists of an inlet filter, counterflow heat exchanger, Joule-Thomson expansion device, and a low pressure jacket. The program objective was to develop a JTX which, when coupled to an open cycle supercritical helium refrigerating system (storage vessel), would supply superfluid helium (He II) at 2 K or less for cooling infrared detectors.

Norman, R. H.

1976-01-01

269

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)

270

Procedure for repairing a heat exchanger  

International Nuclear Information System (INIS)

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

271

Heat exchanger tube inspection using ultrasonic arrays  

International Nuclear Information System (INIS)

Tubing used in industrial heat exchangers is often subject to failure caused by corrosion and cracking. Technical conferences are used as a forum in the steam generator industry to ensure that the failure mechanisms are well understood and that the quality of the heat exchanger is maintained. The quality of a heat exchanger can be thought of as its ability to operate to design specifications over its intended life. This is the motivation to inspect and evaluate these devices periodically. Inspection, however, normally requires shutdown of the heat exchanger which is costly but is much more acceptable than an unscheduled shutdown due to failure of a tube. Therefore, the degree of inspection is established by balancing the cost of inspection with the risk of a tube failure. Any method of reducing the cost of inspection will permit a higher degree of inspection and, therefore, improve heat exchanger quality. This paper reviews the design and performance of an improved method of ultrasonic inspection of heat exchanger tubing with emphasis on applications in the nuclear industry

272

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

273

Device for supporting flat heat exchange packets for recuperative heat exchange  

International Nuclear Information System (INIS)

A honeycombed structure of the supporting framework allows to place very closely a great number of adjacent tube-shaped cases which contain the heat exchanger sets connected in parallel. Thus individual components of the heat exchangers are easily accessible fact which is of great advantage for heat exchangers operating in HTRs being subject to high dynamic loads which are due to pressure- and temperature variations. (GL)

274

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

275

Brayton-cycle heat exchanger technology program  

Science.gov (United States)

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

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

1976-01-01

276

PENGARUH TEBAL ISOLASI TERMAL TERHADAP EFEKTIVITAS PLATE HEAT EXCHANGER  

OpenAIRE

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 ...

Ekadewi Anggraini Handoyo

2000-01-01

277

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

278

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

Science.gov (United States)

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

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

279

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

280

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

OpenAIRE

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 ...

Simarpreet Singh; Sanjeev Jakhar

2014-01-01

281

The Circulating Balls Heat Exchanger (CIBEX)  

Science.gov (United States)

The CIBEX heat exchanger consists of a gas cooling section (gas generator) and an air heating section (air preheater) coupled with a stream of solid particles. The stream of particles falls through a hot gas stream, picking up heat and cooling the gas, then through the air stream, heating the latter. The cooled particles are then returned to the top of the device and the heating/cooling cycle repeated. The paper describes the two-phase equations of motion for the flow of the spherical particles through the fluid. The solid phase is treated as a pseudo-gas by using concentrations instead of density. The equations are then non-dimensionalized and solved by numerical integration. The solution gives temperature and velocity profiles for the two phases for parametric variations in the solid loading and the fluid flux rate. The solution is applied for the design of a heat exchanger for a hypothetical 2500 tons/day coal gasification plant. The dimensions of the CIBEX heat exchanger are much smaller than those of a comparable conventional heat exchanger.

Gat, N.

1986-06-01

282

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

283

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

284

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

285

Improvements in or relating to heat exchangers  

International Nuclear Information System (INIS)

According to the present invention there is provided a method of producing superheated steam by use of the heat in liquid sodium, in which liquid sodium is caused to flow through a space having boundaries of which no part is common with the boundaries of a space in which vapour is produced, a fluid that is inert to sodium is heated by heat exchange at the boundaries of the space through which the liquid sodium flows and serves as the heating medium for the production of vapour, and the vapour is subsequently heated to the final degree of superheat by heat exchange with liquid sodium in a space that has a common boundary with a space through which liquid sodium is passed. (U.K.)

286

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.)

287

Intermediate heat exchanger project for Super Phenix  

International Nuclear Information System (INIS)

The design of the intermediate heat exchangers for the Super Phenix was derived directly from the design used in the Phenix, which has been linked to the electrical grid since late 1973. These heat exchangers permit the transfer of thermal energy from the core, by way of the radioactive primary sodium which is confined to the principal reactor vessel, to the secondary sodium which brings the heat to the steam generators. Discussed in particular is the tube bundle which is the active part of the heat exchanger. From a similar geometry in the two reactors Phenix and Super Phenix, straight tubes were designed, without expansion joints, supported by tube constraint systems, and soldered to two ring-shaped plates. The tubes have a 14 mm exterior diameter and a 1 mm thickness and they are fastened to the plates in cylindrical layers with a 19 mm radial pitch and an approximately 20 mm circular pitch

288

The dry heat exchanger calorimeter system  

International Nuclear Information System (INIS)

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

289

40 CFR 63.1409 - Heat exchange system provisions.  

Science.gov (United States)

...where the cooling water enters and exits each heat exchanger or any combination of heat exchangers. (i) For samples taken at the entrance...samples taken at the entrance and exit of each heat exchanger or any combination of heat exchangers,...

2010-07-01

290

40 CFR 63.104 - Heat exchange system requirements.  

Science.gov (United States)

...where the cooling water enters and exits each heat exchanger or any combination of heat exchangers. (i) For samples taken at the entrance...samples taken at the entrance and exit of each heat exchanger or any combination of heat exchangers in...

2010-07-01

291

Compact ceramic heat-exchangers: design, fabrication and testing  

Energy Technology Data Exchange (ETDEWEB)

The efficiency, application and production of ceramic compact heat exchangers made from silicon infiltrated silicon carbide is discussed. Processing techniques for plate type heat exchangers, component design, the design of the testing facility for ceramic heat exchanger elements and performance data of the standard design of ceramic cross flow heat exchanger are outlined.

Heinrich, J.; Huber, J.; Schelter, H.; Ganz, R.; Golly, R.; Foerster, S.; Quell, P.

292

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

Directory of Open Access Journals (Sweden)

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

Malkin E. C.

2010-03-01

293

Heat recovery equipment for engines  

Energy Technology Data Exchange (ETDEWEB)

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

Segaser, C.L.

1977-04-01

294

RECITAL SCRUTINY ON TUBE-INTUBE COMPACT HEAT EXCHANGERS  

OpenAIRE

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...

V.NATARAJAN,; Senthil Kumar, Dr P.

2011-01-01

295

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)ery dependent on preload. (author)

296

Analysis of Heat Transfer Enhancement in Spiral Plate Heat Exchanger  

OpenAIRE

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....

Kaliannan Saravanan; Rangasamy Rajavel

2009-01-01

297

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

298

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 upon each repetition

299

Experience with the PFR decay heat removal air heat exchangers  

International Nuclear Information System (INIS)

In the Prototype Fast Reactor (PFR) decay heat during shutdown is normally removed by the steam plant. In the event of the steam plant being unavailable, shutdown heat is removed by the decay heat removal system which consists of three NaK loops with air heat exchangers (AHXs). PFR commenced operation in 1974. During service a number of NaK leaks occurred in the AHXs. Investigation showed that temperature differentials between the finned tubes were generating differences in expansion which led to high strain at the joints between the tubes and the headers, eventually resulting in failure of the joint by fatigue. A system of continuous condition monitoring was introduced to ensure the availability of the decay heat removal system while Replacement Air Heat Exchangers (RAHXs) of improved design were manufactured. The first two redesigned units were installed in 1986 and subsequent operation confirmed that the temperature differential problem had been eliminated

300

Screen heat exchanger performance comparison  

Science.gov (United States)

The performance of stainless steel screen regenerator stacks (500 mesh) has been investigated at relatively small flow rates in comparison to conventional operation close to the laminar-turbulent transition range. A modified 'single blow' technique was used initially, and an additional comparative procedure is employed to deduce heat transfer rate ratios with respect to a single-wire reference case of heat transfer. The data obtained are two orders of magnitude below 'classical' room temperature values at low Reynolds number (Re); (Re based on the Darcy law-related characteristic length; Re less than 1). The fluid is cold nitrogen from a liquid bath at atmospheric pressure.

Luna, J.; Ravikumar, K. V.; Frederking, T. H. K.

301

Modeling particle deposition on HVAC heat exchangers  

International Nuclear Information System (INIS)

Fouling of fin-and-tube heat exchangers by particle deposition leads to diminished effectiveness in supplying ventilation and air conditioning. This paper explores mechanisms that cause particle deposition on heat exchanger surfaces. We present a model that accounts for impaction, diffusion, gravitational settling, and turbulence. Simulation results suggest that some submicron particles deposit in the heat exchanger core, but do not cause significant performance impacts. Particles between 1 and 10(micro)m deposit with probabilities ranging from 1-20% with fin edge impaction representing the dominant mechanism. Particles larger than 10(micro)m deposit by impaction on refrigerant tubes, gravitational settling on fin corrugations, and mechanisms associated with turbulent airflow. The model results agree reasonably well with experimental data, but the deposition of larger particles at high velocities is underpredicted. Geometric factors, such as discontinuities in the fins, are hypothesized to be responsible for the discrepancy

302

Analysis of compact heat exchanger performance  

Science.gov (United States)

Many cryogenic heat exchangers employ high-conductance metallic screens or perforated plates separated by insulating spacers normal to the fluid flow direction. Packed-bed regenerators employing wire screens, perforated plates, or granular particles also have a similar structure. The temperature profile along the length consists of many steps. The ineffectiveness due to axial conduction adds to that due to finite number of plates and finite heat transfer coefficient. A closed form expression is derived for the efficiency of a compact heat exchanger with given design N sub tu where the exchanger consists of layers of metallic screens, plates, or particle layers. It is observed that the effect of discrete temperature profile becomes significant when the per stage design N sub tu exceeds about 0.5.

Sarangi, S.; Barclay, J. A.

1984-12-01

303

Diffusion bonding in compact heat exchangers  

International Nuclear Information System (INIS)

Heatric's diffusion bonding process is a solid-state joining technology that produces strong, compact, all-metal heat exchanger cores. Diffusion bonding allows for a large quantity of joints to be made in geometries that would normally be inaccessible for conventional welding techniques. Since Heatric's diffusion bonding process uses no interlayer or braze alloy, the resulting heat exchanger core has consistent chemistry throughout and, under carefully controlled conditions, a return to parent metal strength can be reached. This paper will provide an overview of the diffusion bonding process and its origins, and also its application to compact heat exchanger construction. The paper will then discuss recent work that has been done to compare mechanical properties of Heatric's diffusion bonded material with material that has been conventionally welded, as well as with material tested in the as-received condition. (author)

304

High temperature helium heat exchange loop  

International Nuclear Information System (INIS)

Before realizing a nuclear plant complex for iron and steel making, several technical problems remain to be solved in the high temperature heat exchanger and the steam reformer. The loop described was planned by the Iron and Steel Institute of Japan for basic studies on these problems and was turned over to Ishikawajima Harima Heavy Industries for its actual construction on behalf of ISIJ. The loop was designed for carrying out research on heat exchange between helium and steam, hydrogen permeation through super alloys, hydrogen removal using a titanium sponge, and creep carburization performance of super alloys. The primary coolant used was helium having a pressure of approx. 12 kg/cm2g and a measured temperature of approx. 1,1000C at the inlet of the high temperature heat exchanger, i.e., the test section. Steam, hydrogen and carbon monoxide were used as secondary coolants. (author)

305

Numerical Simulation of Passive Residual Heat Removal Heat Exchanger  

International Nuclear Information System (INIS)

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

306

AP600 passive residual heat removal heat exchanger test  

International Nuclear Information System (INIS)

The AP600 reactor is a pressurized water reactor being designed to utilize a passive residual heat removal (PRHR) heat exchanger as the safety grade means for residual heat removal. The PRHR heat exchanger is utilized during many design basis events and is especially important in mitigating non-loss-of-coolant accidents such as loss of normal feedwater and feedwater line break. The PRHR system transfers decay heat from the reactor coolant system to the containment by heating and boiling the water in the in-containment refueling water storage tank (IRWST). The steam produced transfers heat to the atmosphere by condensing on the inside of the containment shell. The condensate is collected by gutters on the containment shell and is returned to the IRWST, which provides a heat sink for an indefinite amount of time. The PRHR test facility is a prototypical representation of the PRHR heat exchanger with respect to tube material, diameter, pitch, and tube length, such that the gravity-induced flow characteristics in the pool are representative of the design. The main scaling parameter for the pool is the pool volume per tube, which preserves the buoyancy and pool mixing effects. A generalized PRHR boiling correlation was developed using the approach given by Rohsenow such that pressure effects can be induced

307

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

308

MICROMACHINED HEAT EXCHANGER FOR A CRYOSURGICAL PROBE  

OpenAIRE

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 ...

Zhu, W.; Gianchandani, Yogesh B.; Nellis, G. F.; Klein, Sanford A.

2005-01-01

309

Tube-in-shell heat exchangers  

International Nuclear Information System (INIS)

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

310

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

OpenAIRE

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

Jalaluddin

2011-01-01

311

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 tertssor 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

312

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

313

Heat exchanger including an auxiliary cooling system  

International Nuclear Information System (INIS)

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

314

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

315

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

316

Heat exchanger and the associated pipe  

International Nuclear Information System (INIS)

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

317

Exergo-ecological evaluation of heat exchanger  

Directory of Open Access Journals (Sweden)

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

Stanek Wojciech

2014-01-01

318

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

319

Inspection system for heat exchanger tubes  

International Nuclear Information System (INIS)

This invention relates to an inspection system employing eddy current testing for determining, in-situ in heat exchanger tubes, the location, physical dimensions and character of abnormalities such as, but not limited to, dents, out-of-roundness, inside diameter variations and the like

320

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)

321

New plates for different types of plate heat exchangers  

OpenAIRE

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

322

Heat Exchanger Design in Combined Cycle Engines  

Science.gov (United States)

Combined cycle engines employing both pre-cooled air-breathing and rocket modes of operation are the most promising propulsion system for achieving single stage to orbit vehicles. The air-breathing phase is purely for augmentation of the mission velocity required in the rocket phase and as such must be mass effective, re-using the components of the rocket cycle, whilst achieving adequate specific impulse. This paper explains how the unique demands placed on the air-breathing cycle results in the need for sophisticated thermodynamics and the use of a series of different heat exchangers to enable precooling and high pressure ratio compression of the air for delivery to the rocket combustion chambers. These major heat exchanger roles are; extracting heat from incoming air in the precooler, topping up cycle flow temperatures to maintain constant turbine operating conditions and extracting rejected heat from the power cycle via regenerator loops for thermal capacity matching. The design solutions of these heat exchangers are discussed.

Webber, H.; Feast, S.; Bond, A.

323

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

324

Predicting particle deposition on HVAC heat exchangers  

Science.gov (United States)

Particles in indoor environments may deposit on the surfaces of heat exchangers that are used in heating, ventilation and air conditioning (HVAC) systems. Such deposits can lead to performance degradation and indoor air quality problems. We present a model of fin-and-tube heat-exchanger fouling that deterministically simulates particle impaction, gravitational settling, and Brownian diffusion and uses a Monte Carlo simulation to account for impaction due to air turbulence. The model predicts that <2% of submicron particles will deposit on heat exchangers with air flows and fin spacings that are typical of HVAC systems. For supermicron particles, deposition increases with particle size. The dominant deposition mechanism for 1-10 ?m particles is impaction on fin edges. Gravitational settling, impaction, and air turbulence contribute to deposition for particles larger than 10 ?m. Gravitational settling is the dominant deposition mechanism for lower air velocities, and impaction on refrigerant tubes is dominant for higher velocities. We measured deposition fractions for 1-16 ?m particles at three characteristic air velocities. On average, the measured results show more deposition than the model predicts for an air speed of 1.5 m s -1. The amount that the model underpredicts the measured data increases at higher velocities and especially for larger particles, although the model shows good qualitative agreement with the measured deposition fractions. Discontinuities in the heat-exchanger fins are hypothesized to be responsible for the increase in measured deposition. The model and experiments reported here are for isothermal conditions and do not address the potentially important effects of heat transfer and water phase change on deposition.

Siegel, Jeffrey A.; Nazaroff, William W.

325

Triple loop heat exchanger for an absorption refrigeration system  

Science.gov (United States)

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

326

AUTOMATIC EVOLUTION OF HEAT EXCHANGER NETWORKS WITH SIMULTANEOUS HEAT EXCHANGER DESIGN  

OpenAIRE

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

327

Air duct heat exchanger; Luftkanal-Waermetauscher  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

328

Preliminary SP-100/Stirling heat exchanger designs  

International Nuclear Information System (INIS)

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

329

Preliminary SP-100/Stirling heat exchanger designs  

Science.gov (United States)

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

Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brian; Dunn, Pat

1993-01-01

330

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

331

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

332

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

333

Thermal induced flow oscillations in heat exchangers for supercritical fluids  

Science.gov (United States)

Analytical model has been developed to predict possible unstable behavior in supercritical heat exchangers. From complete model, greatly simplified stability criterion is derived. As result of this criterion, stability of heat exchanger system can be predicted in advance.

Friedly, J. C.; Manganaro, J. L.; Krueger, P. G.

1972-01-01

334

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

335

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

336

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

International Nuclear Information System (INIS)

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

337

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

338

Gentilly-2 moderator heat exchanger repair  

International Nuclear Information System (INIS)

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)

339

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

340

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

341

Tube bundle restraint in heat exchangers  

International Nuclear Information System (INIS)

A tube supporting grid mounted within a tube bundle shroud of a heat exchanger e.g. a steam generator is fixed against lateral and axial movement by pins spaced at 900 intervals around the grid flange and by rings located on opposite axial sides of the grid flange. The pins allow radial expansion and contraction of the grid, and the arrangement of pins and rings also facilitates alignment of the grids prior to tubing, and resists movement during seismic incidents. (Author)

342

Pipe plate and assembly for heat exchanger  

International Nuclear Information System (INIS)

The pipe assembly, especially for heat exchangers, consists of a pair of horizontal plates connected by a cylindrical tube with a side entry port connected with the space between the plates. The tube has a thicker section and smaller internal diameter at the ends where it holds a smaller outer diameter cylindrical tube. The end joints of the tubes and plates are soldered. The design is relevant to detection of leaks in sodium cooled nuclear power reactors. (G.C.)

343

Heat Exchanger for Motor Vehicle Cooling System  

OpenAIRE

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

344

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

345

Heat exchanger support apparatus in a fluidized bed  

Science.gov (United States)

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

346

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

347

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

348

Inner inspection device for heat exchanger  

International Nuclear Information System (INIS)

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

349

Heat transfer characteristics of a plate-fin type supercritical/liquid helium heat exchanger  

Science.gov (United States)

A compact supercritical-helium/liquid-helium heat exchanger composed of a plate-fin type was studied. The heat exchange limit performance was determined through the experiment. The pulse heating performance was observed to apply the pulse heating by an electric heater. A numerical heat exchanger simulating calculation was carried out, which successfully expresses the experiment results.

Kato, T.; Miyake, A.; Hiyama, T.; Kawano, K.; Iwamoto, S.; Ebisu, H.; Takahashi, T.; Hamada, K.; Tsuji, H.; Tsukamoto, N.; Yamaguchi, M.; Ishida, H.; Honda, T.; Yamanishi, A.; Ohmori, T.; Mori, M.

350

CHARACTERIZATION OF HEAT TRANSFER AND EVAPORATIVE COOLING OF HEAT EXCHANGERS FOR SORPTION BASED SOLAR COOLING APPLICATIONS  

OpenAIRE

The content of this Master thesis is the characterization of three different cross unmixed flow heat exchangers. All of the heat exchangers have different inner geometries and dimensions. In order to perform the characterization of these heat exchangers, measurements of heat transfer were done under different conditions: five different temperatures at the inlet of the sorption side, different mass flow for both inlet sides of the heat exchangers.The heat transfer measurements were done with a...

Gonza?lez Morales, Ce?sar Augusto

2013-01-01

351

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

352

The Conduction of Heat through Cryogenic Regenerative Heat Exchangers  

Science.gov (United States)

The need for improved regenerative cryocooler efficiency may require the replacement of conventional matrices with ducts. The ducts can not be continuous in the direction of temperature gradient when using conventional materials to prevent unacceptable conduction losses. However, this discontinuity creates a complex geometry to model and determine conduction losses. Chesapeake Cryogenics, Inc. has designed, fabricated and tested an apparatus for measuring the heat conduction through regenerative heat exchangers implementing different matrices. Data is presented for stainless steel photo etched disk, phophorus-bronze embossed ribbon coils and screens made of both stainless steel and phosphorus-bronze. The heat conduction was measured with the regenerators evacuated and pressurized with helium gas. In this test apparatus, helium gas presence increased the heat leak significantly. A description of the test apparatus, instrumentation, experimental methods and data analysis are presented.

Superczynski, W. F.; Green, G. F.

2006-04-01

353

Heat exchange following atropine injection before and after heat acclimation.  

Science.gov (United States)

The effect of saline and atropine injection (2 mg, im) on eight healthy male subjects before and after heat acclimation was studied while each subject walked on a treadmill (1.34 m X s-1) in a hot-dry environment (ambient temperature = 48.4 degrees C, dew-point temperature = 20.5 degrees C). Partitional calorimetric analysis was done for the periods in which maximum sweat inhibition occurred (30 min). Mean skin temperature, rectal temperature, and heart rate were continuously observed. Evaporative loss from the skin was calculated by changes in body weight (Sauter balance); heat transfer coefficients were defined by Nishi equations. A prediction of sweat inhibition based on an analysis of heat storage and its effect on a theoretical temperature, which can be graphed on a psychrometric chart, was developed. A rational effective temperature (ET) defined as the operative temperature at the intersection of the 50% rh, which encompasses total heat exchange, was used to compare the effects of atropine before and after heat acclimation. The results show that heat acclimation reduced ET by approximately 2.5 degrees C when compared with the unacclimated state after atropine injection. Thus heat acclimation reduces the hazards of heatstroke caused by exercise in the heat with atropine injection. PMID:6725067

Kolka, M A; Holden, W L; Gonzalez, R R

1984-04-01

354

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

355

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

356

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

357

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.

1999-03-01

358

PENGARUH TEBAL ISOLASI TERMAL TERHADAP EFEKTIVITAS PLATE HEAT EXCHANGER  

Directory of Open Access Journals (Sweden)

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

Ekadewi Anggraini Handoyo

2000-01-01

359

Heat Exchanger Anchors for Thermo-active Tunnels  

OpenAIRE

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...

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

2013-01-01

360

Heat transfer analysis of flat and louvered fin-and-tube heat exchangers using CFD  

OpenAIRE

This paper analyzes the fluid flow and heat exchange on the air side of a multi-row fin-and-tube heat exchanger. A comparison is given between fin-and-tube heat exchanger characteristics with flat and louvered fins in a wider range of operating conditions defined by Reynolds number (based on fin spacing and air frontal velocities). The detailed representation of calculated data for the louvered heat exchanger shows significantly better heat transfer characteristics and a ...

Carija, Z.; Frankovic, B.

2008-01-01

361

Experimental evaluation of sodium to air heat exchanger performance  

International Nuclear Information System (INIS)

Highlights: ? Sodium to air heat exchangers are used to remove the decay heat produced in fast breeder reactor after shutdown. ? Finned tube sodium to air heat exchanger with sodium on tube side was tested for its heat transfer performance. ? A one dimensional computer code was validated by the experimental data obtained. ? Non uniform sodium and air flow distribution was present in the heat exchanger. - Abstract: Sodium to air heat exchangers (AHXs) is used in Prototype Fast Breeder Reactor (PFBR) circuits to reject the decay heat produced by the radioactive decay of the fission products after reactor shutdown, to the atmospheric air. The heat removal through sodium to air heat exchanger maintains the temperature of reactor components in the pool within safe limits in case of non availability of normal heat transport path. The performance of sodium to air heat exchanger is very critical to ensure high reliability of the decay heat removal systems in sodium cooled fast breeder reactors. Hence experimental evaluation of the adequacy of the heat transfer capability gives confidence to the designers. A finned tube cross flow sodium to air heat exchanger of 2 MW heat transfer capacity with sodium on tube side and air on shell side was tested in the Steam Generator Test Facility at Indira Gandhi Center for Atomic Research, India. Heat transfer experiments were carried out with forced circulation of sodium and air, which confirmed the adequacy of heat removal capacity of the heat exchanger. The testing showed that 2.34 MW of heat power is transferred from sodium to air at nominal flow and temperature conditions. A one dimensional computer code developed for design and analysis of the sodium to air heat exchanger was validated by the experimental data obtained. An equivalent Nusselt number, Nueq is derived by approximating that the resistance of heat transfer from sodium to air is contributed only by the film resistance of air. The variation of Nueq with respect to the Reynolds number was studied

362

Fluid dynamical considerations on heat exchanger networks  

Directory of Open Access Journals (Sweden)

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

Vieira A. J. M.

2000-01-01

363

Studying dynamical characteristics of heat exchangers  

International Nuclear Information System (INIS)

The dynamical charcteristics of the heat exchanger representing a horizontal apparatus with a flexible integrated pressurizer are studied. The design analysis for three different fasteners is performed. The computer calculation is performed by the method of finite elements. It is shown that the combination of calculation studies with equipment simulation with the use of models allows to establish reliably main dynamical equipment characteristics and to find out the effect of rigidity of certain construction elements, fastening conditions and presence of liquid on frequency values of free structure vibrations

364

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.

2000-03-01

365

Heat exchange tube acoustic excitation response analysis  

International Nuclear Information System (INIS)

In the present paper, heat exchange tube resistance to an acoustic field, is studied particularly in the case where the tubes are to be located either at the suction or discharge end of a compressor or upstream from a sonic relief valve or even mounted between these two elements. The aim is to estimate the stress levels involved with a view to arriving at a tube lifetime assessment, from which could be derived a preliminary design calculation method to be used by the design engineering teams at preliminary project stage

366

Characterization of various losses in a cryogenic counterflow heat exchanger  

Science.gov (United States)

A detailed assessment of irreversibility, predominantly heat in-leak and axial wall conduction, is essential in accurately predicting the performance of high effectiveness heat exchangers employed in cryogenic applications. Integration into a refrigeration system as well requires consideration of parasitic heat loss by conduction from exchanger cold end to the adjacent components. Governing equations incorporating these effects in a counterflow exchanger are solved numerically and the model predictions evaluated for heat exchanger ineffectiveness and heat loss by conduction. The optimum performance mandates minimization of both. Although ineffectiveness decreases at higher longitudinal conduction, cold end loss increases with deterioration of the overall performance. Utilizing lower heat capacity rate hot fluid, nevertheless, reduces the cold end loss. Heat in-leak is relatively high with concurrent consideration of axial wall conduction and has adverse consequence on heat exchanger effectiveness. Analysis of the net heat transferred to lower stages of refrigeration reveals a critical NTU.

Aminuddin, Mohammad; Zubair, Syed M.

2014-11-01

367

Aerodynamics of heat exchangers for high-altitude aircraft  

Science.gov (United States)

Reduction of convective beat transfer with altitude dictates unusually large beat exchangers for piston- engined high-altitude aircraft The relatively large aircraft drag fraction associated with cooling at high altitudes makes the efficient design of the entire heat exchanger installation an essential part of the aircraft's aerodynamic design. The parameters that directly influence cooling drag are developed in the context of high-altitude flight Candidate wing airfoils that incorporate heat exchangers are examined. Such integrated wing-airfoil/heat-exchanger installations appear to be attractive alternatives to isolated heat.exchanger installations. Examples are drawn from integrated installations on existing or planned high-altitude aircraft.

Drela, Mark

1996-01-01

368

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

369

Simulation Studies on A Cross Flow Plate Fin Heat Exchanger  

Directory of Open Access Journals (Sweden)

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

M. Thirumarimurugan

2008-01-01

370

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

International Nuclear Information System (INIS)

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

371

Hierarchic modeling of heat transfer processes in heat exchangers  

Energy Technology Data Exchange (ETDEWEB)

An alternate approach based on hierarchic modeling is proposed to simulate fluid and heat flow in heat exchangers. On the first level, the direct simulations have been performed for the geometry that is similar to a segment of the examined heat sink. Based on the obtained results, the Reynolds number dependencies of the scaling factors f and StPr{sup 2/3} have been established. On the second level, the integral model of the whole heat sink has been built using the volume averaging technique (VAT). The averaging of the transport equations leads to a closure problem. The direct model Reynolds number dependencies f and StPr{sup 2/} {sup 3} have been used to calculate the local values of the drag coefficient C-circumflex{sub d} and the heat transfer coefficient {theta}-circumflex, which are needed in the integral model. The example calculations have been performed for 14 different pressure drops {delta}p-bar across the aluminum heat sink. The whole-section drag coefficient C-bar{sub d} and Nusselt number Nu-bar have been calculated and compared with the experimental data [M. Rizzi, M. Canino, K. Hu, S. Jones, V. Travkin, I. Catton, Experimental investigation of pin fin heat sink effectiveness, in: Proc. of the 35th National Heat Transfer Conference Anaheim, California, 2001]. A good agreement between the modeling results and the experiment data has been reached with same discrepancies in the transitional regime. The constructed computational algorithm offers possibilities for geometry improvements and optimization, to achieve higher thermal effectiveness. (author)

Horvat, A.; Mavko, B. [Jozef Stefan Inst., Ljubljana (Slovenia). Reactor Engineering Division

2005-01-01

372

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

373

Condensate removal device for heat exchanger  

Science.gov (United States)

A set of perforated tubes disposed at the gas output side of a heat exchanger, in a position not to affect the rate of flow of the air or other gas is described. The tubes are connected to a common manifold which is connected to a sucking device. Where it is necessary to conserve and recirculate the air sucked through the tubes, the output of the manifold is run through a separator to remove the condensate from the gas. The perforations in the slurper tubes are small, lying in the range of 0.010 inch to 0.100 inch. The tubes are disposed in contact with the surfaces of the heat exchanger on which the condensate is precipitated, whether fins or plates, so that the water may be directed to the tube openings by means of surface effects, together with the assistance of the air flow. Only about 5 percent of the air output need be thus diverted, and it effectively removes virtually all of the condensate.

Trusch, R. B.; Oconnor, E. W. (inventors)

1975-01-01

374

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

375

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

376

Theoretical and experimental study of geothermal spiral heat exchangers : Heating and cooling with heat pumps, and dimensioning systems  

OpenAIRE

This thesis consists in a study of geothermal helical heat exchangers buried in the close underground. These objects belong to the compact exchangers kind and may be used instead of borehole heat exchanger or geothermal horizontal exchangers to cope with the needs in heating and cooling buildings with a heat pump. A theoretical and experimental study of these exchangers leads to numerical and analytical models which can be used to estimate the temperatures in the underground and in the exchan...

Moch, Xavier

2013-01-01

377

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

378

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.)

379

Study of hydraulic resistance and heat transfer in perforated-plate heat exchangers  

Science.gov (United States)

An experimental study is made of the hydraulic resistance and heat transfer in heat exchangers made of perforated plates with different internal geometries. Generalizing theoretical relations are obtained.

Shevyakova, S. A.; Orlov, V. K.

1983-07-01

380

Geothermal direct contact heat exchange. Final report  

Energy Technology Data Exchange (ETDEWEB)

A glass direct contact heat exchange column was operated in the laboratory. The column was operated at atmospheric pressure using hot water and normal hexane. Column internals testing included an empty column, sieve trays, disk-and-doughnut trays, and two types of packing. Operation was very smooth in all cases and the minimum temperature approaches varied from less than 1/sup 0/C for packing to 13/sup 0/C for the empty column. High heat transfer rates were obtained in all cases, however, columns should be sized on the basis of liquid and vapor traffic. The solubilities of hydrocarbons were determined for normal hexane, pentane and butane in water and sodium chloride and calcium chloride brines at various temperatures. The values seem to be internally consistent and salt content was found to depress hydrocarbon solubility. Laboratory stripping tests showed that gas stripping can be used to remove hydrocarbon from reject hot water from the direct contact heat exchange column. Although the gas volumes required are small, stripping gas requirements cannot be accurately predicted without testing. A computer program was used to study the effect of operating variables on the thermodynamic cycle efficiencies. Optimum efficiencies for the moderate brine conditions studied were obtained with isopentane as working fluid and relatively low operating pressure. A preliminary design for a 50 MWe plant was prepared and plant capital cost and operating cost were estimated. These costs were combined with previously developed brine production and power transmission costs to provide an estimate of the cost of delivered power for a geothermal field at Heber, California. A pilot plant program is described that would be suitable for continuing the investigation of the direct contact process in the field. The program includes a suggested schedule and the estimated cost.

Sims, A.V.

1977-06-10

381

Heat exchanger for fuel cell power plant reformer  

Science.gov (United States)

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

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

1988-01-01

382

Heat transfer entropy resistance for the analyses of two-stream heat exchangers and two-stream heat exchanger networks  

International Nuclear Information System (INIS)

The entropy generation minimization method is often used to analyze heat transfer processes from the thermodynamic viewpoint. In this paper, we analyze common heat transfer processes with the concept of entropy generation, and propose the concept of heat transfer entropy resistance. It is found that smaller heat transfer entropy resistance leads to smaller equivalent thermodynamic force difference with prescribed heat transfer rate and larger heat transfer rate with prescribed equivalent thermodynamic force difference. With the concept of heat transfer entropy resistance, the performance of two-stream heat exchangers (THEs) and two-stream heat exchanger networks (THENs) is analyzed. For the cases discussed in this paper, it is found that smaller heat transfer entropy resistance always leads to better heat transfer performance for THEs and THENs, while smaller values of the entropy generation, entropy generation numbers and revised entropy generation number do not always. -- Highlights: • The concept of entropy resistance is defined. • The minimum entropy resistance principle is developed. • Smaller entropy resistance leads to better heat transfer

383

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

OpenAIRE

In this master thesis report the development of an innovative spiral heat exchanger based on polymer materials is described. Building prototypes, erection of a test bench and firsts tests of the heat exchanger are presented. The heat exchanger prototype survived all tests especially several days in contact with aggressive gases. A facility integrating a Diesel exhaust gases production has been developed to test this heat exchanger design. Performance results obtained during the tes...

Breton, Antoine

2012-01-01

384

Heat transfer with phase change in plate-fin heat exchangers  

Science.gov (United States)

A theoretical and experimental study was conducted for convective evaporation and condensation in plate-fin compact heat exchangers. The overall performance of a brazed-aluminum heat exchanger in the evaporation mode with ammonia and in the condensation mode with both ammonia and refrigerant R-22 as working fluids. The heat exchanger has straight perforated fins on the working-fluid side and extruded rectangular channels on the single-phase (water) side. The two-phase flow in narrow channels of the heat exchanger is modeled using a triangular relationship between pressure gradient, liquid film flow rate, and film thickness. The overall performance of the heat exchanger is calculated by employing local heat-transfer analysis and integrating mass- and heat-balance equations along the heat-exchanger length. Theoretical predictions are found to agree favorably with experimental results for a prototypical heat exchanger unit.

Panchal, C. B.

1984-08-01

385

Compact high efficiency perforated-plate heat exchangers  

International Nuclear Information System (INIS)

A feasibility study into the use of perforated-plate heat exchangers in helium refrigerators is reported. Investigation into the optimization of efficiency by variation of the hole diameter along the exchanger is discussed. The difficulties in design of vacuum-tight connections between plates and spaces are considered. Data obtained from calculations of heat transfer parameters have been used to design a helium refrigerator perforated-plate heat exchanger for which performance figures are given. (U.K.)

386

Combined heat exchanger of smoke gases by Evrovartrade company  

OpenAIRE

The aim of my diploma was to introduce a heat exchanger of smoke gases, whitch is a patent by Evrovartrade company. The exchanger can be setted up additionally on the exit side of furnance smoke gases tube. With smoke gases we can heat water, which can be used for industrial or for home heating. With developed exchanger, we can cool smoke gases below saturation temperature, and consecutive enlarge the furnance efficiency up to 11%.

Knez, David

2013-01-01

387

Analysis of supercritical carbon dioxide heat exchangers in cooling process  

OpenAIRE

Carbon dioxide transcritical cycles have become more and more investigated during the last decade. For all systems operating with such a cycle, there will be at least one heat exchanger to either heat or cool the supercritical carbon dioxide. Unlike in the sub-critical region, the supercritical carbon dioxide’s thermophysical properties will have sharp variations in the region close to its critical point. This variation has a significant influence on the shape of the heat exchanger’s temp...

Chen, Yang; Lundqvist, Per

2006-01-01

388

Industrial applications for LIGA-fabricated micro heat exchangers  

Science.gov (United States)

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

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

2001-10-01

389

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-07-01

390

Inservice inspection of PFR secondary heat exchangers  

International Nuclear Information System (INIS)

The author describes the current state of development to meet inservice inspection requirements of secondary heat exchangers of a prototype fast reactor: detection of defects in both the bore and outer surface of the tubes (pitting and cracking in the bore surface and fretting and thinning on the outer), full inspection of bends and straight portions, examination of the tube plate and of the tube/tube plate weld region. He reports the development of an eddy current probe for the in-service inspection (ISI) of the stainless steel tubing in the super-heater and re-heater, describes the influence of sodium concentration on eddy current inspection, and briefly evokes the detection of defects in bends. He describes the eddy current inspection of the evaporator tube bores, the wall thickness measurement in evaporator tubes. Then, he reports the in-service inspection of tube plates: tube bore examination, volumetric examination. He briefly discusses the obtained results

391

FASTEF Heat exchanger tube rupture CFD simulation  

International Nuclear Information System (INIS)

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

392

FASTEF Heat exchanger tube rupture CFD simulation  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-11-15

393

The LUX prototype detector: Heat exchanger development  

International Nuclear Information System (INIS)

The LUX (large underground xenon) detector is a two-phase xenon time projection chamber (TPC) designed to search for WIMP–nucleon dark matter interactions. As with all noble element detectors, continuous purification of the detector medium is essential to produce a large (>1ms) electron lifetime; this is necessary for efficient measurement of the electron signal which in turn is essential for achieving robust discrimination of signal from background events. In this paper, we describe the development of a novel purification system deployed in a prototype detector. The results from the operation of this prototype indicated heat exchange with an efficiency above 94% up to a flow rate of 42 slpm, allowing for an electron drift length greater than 1 m to be achieved in approximately 2 days and sustained for the duration of the testing period

394

The influence of heat exchanger performances on the design of indirect geothermal heating system  

Energy Technology Data Exchange (ETDEWEB)

Geothermal water can be used for heating objects both by direct or indirect systems. Indirect heating system with supplementary heat source is analyzed in this paper, and mathematical model that includes heat transfer in heat exchangers, heat emitting units and heat losses of object is established. Useful diagrams are also given to illustrate mathematical model. (author)

Milanovic, P. [Institute for Chemistry, Technology and Metallurgy, Belgrade (Yugoslavia); Jacimovic, B.; Genic, S. [University of Belgrade (Yugoslavia). Faculty of Mechanical Engineering

2004-01-01

395

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-07-15

396

Experimental study of passive residual heat removal system with air cooled heat exchanger  

International Nuclear Information System (INIS)

The objective of this work is to investigate the heat removal capability of the passive Residual heat removal(RHR) heat exchanger in the advanced PWR system. Two test models were made to simulate the RHR heat exchanger. The one is the single bundle test model which consisted of a finned tubular heat exchanger unit. The other is the multi-bundle test model which has the finned tubular heat exchanger consisting of ten bundles of tubular units. The maximum heat removal capabilities of each model were investigated. The effects of chimney and elevation were observed

397

Analysis of fabrication process for AP1000 passive residual heat removal heat exchanger  

International Nuclear Information System (INIS)

This paper introduces the design parameters of the passive residual heat removal heat exchanger for American advanced passive pressurized water reactor (AP1000), describes the fabrication process for the head, tubesheet, heat exchange tube, corrugated plate and support frame assembly of the heat exchanger, mainly in terms of material, forging, welding, and heat treatment, and also analyzes the crucial steps for the support frame assembling, tubesheet plate welding, tube penetration welding of C tube bundle, closure/head welding, heat treatment, hydraulic (pressure) test, and etc. in the process of heat exchanger assembling. (author)

398

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

International Nuclear Information System (INIS)

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

399

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

OpenAIRE

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

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

2008-01-01

400

WASTE HEAT RECOVERY FROM BOILER OF LARGE-SCALE TEXTILE INDUSTRY  

Directory of Open Access Journals (Sweden)

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

Prateep Pattanapunt

2013-01-01

401

40 CFR 63.104 - Heat exchange system requirements.  

Science.gov (United States)

...Chemical Manufacturing Industry § 63.104 Heat...process equipment in a chemical manufacturing process...exits the plant site or chemical manufacturing process...of heat exchangers in chemical manufacturing process...shall maintain, at all times, the monitoring...

2010-07-01

402

Vertical drum heat exchanger for overheated steam production  

International Nuclear Information System (INIS)

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

403

Simulation Studies on A Cross Flow Plate Fin Heat Exchanger  

OpenAIRE

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

Thirumarimurugan, M.; Kannadasan, T.; Ramasamy, E.

2008-01-01

404

Experimental investigation of passive residual heat removal system with air cooled heat exchanger  

International Nuclear Information System (INIS)

The objective of this work is to obtain the Performance test data for the passive residual heat removal (RHR) heat exchanger in the advanced PWR. The RHR heat exchanger is designed to remove the decay heat with combined effects of the natural circulation of water by means of the thermosyphon at the inside and the natural convection of the air at the outside. Two test models were made to simulate the RHR heat exchanger. The one is the single bundle test model which consisted of a finned tubular heat exchanger unit. The other is the multi-bundle test model which has the finned tubular heat exchanger consisting of ten bundles of tubular units. The Maximum heat removal capabilities of each model were investigated. The cooling water flow rates by the thermosyphon were measured and were in good agreement with the theoretical predictions. The effects of chimney and elevation between the heater and the heat exchanger were investigated

405

Superphenix 1 intermediate heat exchanger fabrication  

International Nuclear Information System (INIS)

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

406

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

International Nuclear Information System (INIS)

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

407

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

Science.gov (United States)

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

Corbett, Robert J.; Miller, Barbara

408

Survey of industrial coal conversion equipment capabilities: heat recovery and utilization. [53 references  

Energy Technology Data Exchange (ETDEWEB)

A scoping survey of the capabilities of industrial heat recovery equipment was conducted to determine their adaptability to proposed coal-conversion complexes. Major categories of heat exchangers included shell-and-tube, periodic-flow and rotary regenerators, heat pipe arrays, direct phase contactors, and steam and organic Rankine cycles for power generation from waste heat. Primary applications encompassed feed-effluent and other process stream interchangers, combustion air preheaters, and heat recovery steam generators (waste heat boiler-superheaters). It is concluded that the single area providing the greatest potential for extending US industrial heat-recovery equipment capabilities as related to coal-conversion processes is a research, development, and testing program to acquire more physical-property and heat-transfer data and more-reliable design correlations.

Gambill, W. R.; Reed, W. R.

1978-07-01

409

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

International Nuclear Information System (INIS)

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

410

Combined Steady-State and Dynamic Heat Exchanger Experiment  

Science.gov (United States)

This paper describes a heat-transfer experiment that combines steady-state analysis and dynamic control. A process-water stream is circulated through two tube-in-shell heat exchangers in series. In the first, the process water is heated by steam. In the second, it is cooled by cooling water. The equipment is pilot-plant size: heat-transfer areas…

Luyben, William L.; Tuzla, Kemal; Bader, Paul N.

2009-01-01

411

HEAT ACCUMULATOR BASED ON THE PHASE TRANSITION WITH A SCREW HEAT EXCHANGER ??????????? ??????? ?? ??????? ????????? ?? ???????? ???????????????  

Directory of Open Access Journals (Sweden)

Full Text Available In the article, we have presented the variant of the heat accumulator based on phase transition with a screw heat exchanger, designed to meet the demands of heat supplying systems in thermal energy storage

Ostashenkov A. P.

2013-09-01

412

An Experimental Investigation of Heat Transfer Coefficients for Spiral Plate Heat Exchanger  

OpenAIRE

Spiral plate heat exchangers play a vital role in cooling high density and high viscous fluids. This paper presents an experimental investigation of convective heat transfer co-efficient for electrolytes using spiral plate heat...

Kaliannan Saravanan; Rangasamy Rajavel

2009-01-01

413

HEAT ACCUMULATOR BASED ON THE PHASE TRANSITION WITH A SCREW HEAT EXCHANGER ??????????? ??????? ?? ??????? ????????? ?? ???????? ???????????????  

OpenAIRE

In the article, we have presented the variant of the heat accumulator based on phase transition with a screw heat exchanger, designed to meet the demands of heat supplying systems in thermal energy storage

Ostashenkov A. P.; Onychin E. M.; Medyakov A. A.

2013-01-01

414

Self-defrosting recuperative air-to-air heat exchanger  

Science.gov (United States)

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

Drake, Richard L. (Delmar, NY)

1993-01-01

415

Corrosion of heat exchanger materials under heat transfer conditions  

International Nuclear Information System (INIS)

Severe pitting has occurred in moderator heat exchangers tubed with Incoloy-800 in Pickering Nuclear Generating Station. The pitting originated on the cooling water side (outside) of the tubes and perforation occurred in less than two years. It was known from corrosion testing at Chalk River Laboratories that Incoloy-800 was not susceptible to pitting in Lake Ontario water under isothermal conditions. Corrosion testing with heat transfer across the tube wall was carried out, and it was noted that severe pitting could occur under deposits formed on the tubes in silty Lake Ontario water. Subsequent testing carried out in co-operation with Ontario Hydro Research Division, investigated the pitting resistance of other candidate tubing alloys: Incoloy-825, 904 L stainless steel, AL-6X, Inconel 625, 70:30 Cu:Ni, titanium, Sanicro-30 and Sanicro-28. Of these, only titanium and Sanicro-28 have not suffered some degree of pitting attack in silt-containing Lake Ontario water. In the absence of silt, and hence deposits, no pitting took place on any of the alloys tested. (author). 3 refs., 4 tabs., 6 figs

416

Corrosion of heat exchanger materials under heat transfer conditions  

International Nuclear Information System (INIS)

Severe pitting has occurred in moderator heat exchangers tubed with Incoloy-800 in Pickering Nuclear Generating Station. The pitting originated on the cooling side (outside) of the tubes and perforation occurred in less than two years. It was known from corrosion testing at CRNL that Incoloy-800 was not susceptible to pitting in Lake Ontario water under isothermal conditions. Corrosion testing with heat transfer across the tube wall was carried out, and it was noted that severe pitting could occur under deposits formed on the tubes in silty Lake Ontario water. Subsequent testing, carried out in co-operation with Ontario Hydro Research Division, investigated the pitting resistance of other candidate tubing alloys: Incoloy-825, 904 L stainless steel, AL-6X, Inconel-625, 70:30 Cu:Ni, titanium, Sanicro-30 and Sanicro-281. Of these, only titanium and Sanicro-28 have not suffered some degree of pitting attack in silt-containing Lake Ontario Water. In the absence of silt, and hence deposits, no pitting took place on any of the alloys tested

417

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

Science.gov (United States)

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

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

1993-01-01

418

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

Science.gov (United States)

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

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

1993-04-01

419

Dynamic responses of heat exchanger tube banks  

International Nuclear Information System (INIS)

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

420

Boundary geometric control of a counter-current heat exchanger  

OpenAIRE

The present article deals with the boundary geometric control of a counter-current heat exchanger whose control is designed considering a model based on two partial derivative equations describing the variations of internal and external temperatures. The objective consists in controlling the internal fluid temperature, at the heat exchanger outlet, by manipulating the jacket temperature at its inlet boundary in spite of the variation of the temperature of the internal fluid at the heat exchan...

Maidi, Ahmed; Diaf, Mohamed; Corriou, Jean-pierre

2009-01-01

421

Heat exchanger with a central area coaxial pipes and peripheral exchange area  

International Nuclear Information System (INIS)

This invention concerns an exchanger with indirect transmission of heat between two fluids, that includes a central area formed of two coaxial pipes and a peripheral exchange area enclosed in an outer ring. Both these areas have counter current circulation. A chamber for collecting the partially cooled fluid from one of the coaxial pipes and for feeding the peripheral exchange area is float fitted with respect to the outer ring. This invention particularly applies to secondary water vaporization exchangers in heat exchange systems for electricity generating nuclear power stations, in which the primary fluid is water under pressure or a melted alkaline metal

422

Comparison of natural convection heat exchangers for solar water heating systems  

Energy Technology Data Exchange (ETDEWEB)

Thermosyphon heat exchangers are used in indirect solar water heating systems to avoid using a pump to circulate water from the storage tank to the heat exchanger. In this study, the authors consider the effect of heat exchanger design on system performance. They also compare performance of a system with thermosyphon flow to the same system with a 40W pump in the water loop. In the first part of the study, the authors consider the impact of heat exchanger design on the thermal performance of both one- and two-collector solar water heaters. The comparison is based on Solar Rating and Certification Corporation (SRCC) OG300 simulations. The thermosyphon heat exchangers considered are (1) a one-pass, double wall, 0.22 m{sup 2}, four tube-in-shell heat exchanger manufactured by AAA Service and Supply, Inc., (the Quad-Rod); (2) a two-pass, double wall, 0.2 m{sup 2}, tube-in-shell made by Heliodyne, Inc., but not intended for commercial development; (3) a one-pass, single wall, 0.28 m{sup 2}, 31 tube-in-shell heat exchanger from Young Radiator Company, and (4) a one-pass single-wall, 0.61 m{sup 2}, four coil-in-shell heat exchanger made by ThermoDynamics Ltd. The authors compare performance of the systems with thermosyphon heat exchangers to a system with a 40 W pump used with the Quad-Rod heat exchanger. In the second part of the study, the effects of reducing frictional losses through the heat exchanger and/or the pipes connecting the heat exchanger to the storage tank, and increasing heat transfer area are evaluated in terms of OG300 ratings.

Davidson, J.; Liu, W.

1998-09-15

423

Investigation of Brazed Plate Heat Exchangers With Variable Chevron Angles  

Directory of Open Access Journals (Sweden)

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

S. Muthuraman

2013-08-01

424

Improvements of U-pipe Borehole Heat Exchangers  

OpenAIRE

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

Acun?a, Jose?

2010-01-01

425

Performance of tubes-and plate fins heat exchangers  

International Nuclear Information System (INIS)

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

426

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

OpenAIRE

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

Pavel Neuberger; Radomír Adamovský; Michaela Še?ová

2014-01-01

427

Microchannel crossflow fluid heat exchanger and method for its fabrication  

Science.gov (United States)

A microchannel crossflow fluid heat exchanger and a method for its fabrication are disclosed. The heat exchanger is formed from a stack of thin metal sheets which are bonded together. The stack consists of alternating slotted and unslotted sheets. Each of the slotted sheets includes multiple parallel slots which form fluid flow channels when sandwiched between the unslotted sheets. Successive slotted sheets in the stack are rotated ninety degrees with respect to one another so as to form two sets of orthogonally extending fluid flow channels which are arranged in a crossflow configuration. The heat exchanger has a high surface to volume ratio, a small dead volume, a high heat transfer coefficient, and is suitable for use with fluids under high pressures. The heat exchanger has particular application in a Stirling engine that utilizes a liquid as the working substance.

Swift, Gregory W. (Los Alamos, NM); Migliori, Albert (Santa Fe, NM); Wheatley, John C. (Los Alamos, NM)

1985-01-01

428

40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?  

Science.gov (United States)

...standards and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or...reactor as the surrogate indicator of heat exchanger system leaks when complying...

2010-07-01

429

The influence of heat exchanger design on the synthesis of heat exchanger networks  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Heat exchanger network (HEN) synthesis has been traditionally performed without accounting for a more detailed unit design, which is important since the final HEN may require unfeasible units. Recently, publications on this matter have appeared, as well as softwares that simultaneously perform synth [...] esis and units design. However, these publications do not clearly show the influence of the new added features on the final HEN. Hence, this work aims at showing that units' design can strongly affect the final HEN. Improvements on heat transfer area and total annual cost estimations, which influence the HEN structural evolution, are the main responsible for that. It is also shown the influence of some design bounds settings, which can indicate an unfeasible unit design and, therefore, the need for a new match search or the maintenance of a loop. An example reported in the literature is used to illustrate the discussion.

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

2000-12-01

430

The influence of heat exchanger design on the synthesis of heat exchanger networks  

Directory of Open Access Journals (Sweden)

Full Text Available Heat exchanger network (HEN synthesis has been traditionally performed without accounting for a more detailed unit design, which is important since the final HEN may require unfeasible units. Recently, publications on this matter have appeared, as well as softwares that simultaneously perform synthesis and units design. However, these publications do not clearly show the influence of the new added features on the final HEN. Hence, this work aims at showing that units' design can strongly affect the final HEN. Improvements on heat transfer area and total annual cost estimations, which influence the HEN structural evolution, are the main responsible for that. It is also shown the influence of some design bounds settings, which can indicate an unfeasible unit design and, therefore, the need for a new match search or the maintenance of a loop. An example reported in the literature is used to illustrate the discussion.

Liporace F.S.

2000-01-01

431

Heat exchanger for cooling a liquid metal by air  

International Nuclear Information System (INIS)

According to the invention, the heat exchanger has an array of vertical tubes arranged along one or, preferentially, several cylindrical and coaxial rows and two toroidal collectors; the tubes are extending between the upper and the lower toroidal collectors. A deflector and a casing enveloping the tubes allow the cooling air to flow in contact with the tubes between a vertical inlet conduit and a vertical outlet conduit. The invention applies, more particularly, to heat exchangers used for cooling the secondary liquid sodium coming from a sodium-sodium heat exchanger immerged in the vessel of a fast neutron reactor