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Coaxial borehole heat exchangers provide a practical method for geothermal energy extraction, but heat transfer efficiency is low. In order to address this problem, three coaxial borehole heat exchangers with vortex generators, based on the enhanced heat transfer theory, are proposed in this paper. The author compared and analyzed the heat transfer performance of three coaxial borehole heat exchangers with vortex generators and those of traditional structures, which explains why the new heat exchanger’s heat transfer mechanism is enhanced. The results demonstrated that the vortex generator can enhance the fluid flow’s turbulent kinetic energy in the coaxial heat exchanger. This generator can also improve the mixing characteristics of the fluid flow and heat transfer. The resultant increase in the inlet flow velocity can decrease the friction coefficient f, increase the Nusselt number and strengthen the coaxial sleeve. As a result, the heat exchange performance of the tubular heat exchanger will also be improved. The thread vortex generator (TVG) heat exchanger outperforms the other three heat exchangers in terms of heat exchange performance, extraction temperature and heat extraction power. The results evidenced that the TVG heat exchanger is better than the smooth tube heat exchanger. The thermal performance coefficient PEC was improved by 1.1 times, and the extraction temperature and heating power were increased by 24.06% and 11.93%, respectively. A solid theoretical foundation is provided by the extracted outcomes for designing and selecting high-efficiency coaxial borehole heat exchangers suitable for geothermal energy extraction.
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Shaimerdenova, К. М., E. R. Schrager, A. S. Tussypbaeva, and Zh K. Nausharban. "Investigation of heat exchange processes in vertically arranged heat exchangers." Bulletin of the Karaganda University. "Physics" Series 94, no. 2 (June 28, 2019): 66–72. http://dx.doi.org/10.31489/2019ph2/66-72.
Mathematical programming model for synthesis of heat exchanger network for distillation unit is established. MINLP problem for heat exchanger network is solved by branch-bound method. Two kinds of heat exchanger network with splitting stream and without splitting stream are obtained. 142 heat exchangers, 8 coolers and 4 heaters are needed in the heat exchanger network without splitting stream. 34 heat exchangers, 8 coolers, 4 heaters, 11 splitters and 11 mixers are needed in the heat exchanger network with splitting stream. The matching situation including heat load, heat exchange area, duty of utilities, flow fraction of splitting, temperature of inlet and outlet, etc. for cold and hot streams in the heat exchanger network with splitting stream is presented in detail, Analysis the relationship between total heat exchange area, total heat load, total capital cost and annual operation cost of the heat exchanger network. Taking the number of heat exchangers and operational flexibility of heat exchange network into consideration, the heat exchanger network with splitting stream is suggested to be selected.
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Lee, Seung-Rae. "Evaluation of Heat Exchange Rate of Different Types of Ground Heat Exchangers." Journal of the Korean Society of Civil Engineers 33, no. 6 (2013): 2393. http://dx.doi.org/10.12652/ksce.2013.33.6.2393.
Rydalina, Natalia, Oleg Stepanov, and Elena Antonova. "The use of porous metals in the design of heat exchangers to increase the intensity of heat exchange." E3S Web of Conferences 178 (2020): 01026. http://dx.doi.org/10.1051/e3sconf/202017801026.
Heat exchangers are widely used in heat supply systems. To increase the efficiency of heat supply systems, heat exchangers with porous metals are proposed to design. There was a test facility set up to study new types of heat exchangers. The countercurrent flow of heat carriers was activated in those heat exchangers. Freon moved through the heat exchanger pores, and water moved through the inner tubes. It should be noted that the porous materials in the heat exchangers differed in the coefficient of porosity. To be compared, one of the heat exchangers did not contain any porous material. The first test cycle proved the feasibility of using porous metals in heat exchange equipment. Afterwards, a simplified mathematical model of the heat exchanger was compiled. Such an analytical form makes a solution convenient for engineering calculations. Numerical calculations based on this model were compared with the experimental data. Heat transfer intensity of materials with different porosity was compared.
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Rostami, Mohammadreza Hasandust, Gholamhassan Najafi, Ali Motevalli, Nor Azwadi Che Sidik, and Muhammad Arif Harun. "Evaluation and Improvement of Thermal Energy of Heat Exchangers with SWCNT, GQD Nanoparticles and PCM (RT82)." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 79, no. 1 (December 31, 2020): 153–68. http://dx.doi.org/10.37934/arfmts.79.1.153168.
Today, due to the reduction of energy resources in the world and its pollutants, energy storage methods and increase the thermal efficiency of various systems are very important. In this research, the thermal efficiency and energy storage of two heat exchangers have been investigated in series using phase change materials (RT82) and single wall carbon nanotubes (SWCNT) and graphene quantum dot nanoparticles (GQD) In this research, two heat exchangers have been used in combination. The first heat exchanger was in charge of storing thermal energy and the second heat exchanger was in charge of heat exchange. The reason for this is to improve the heat exchange of the main exchanger (shell and tube) by using heat storage in the secondary exchanger, which has not been addressed in previous research. The results of this study showed that using two heat exchangers in series, the thermal efficiency of the system has increased. Also, the heat energy storage of the double tube heat exchanger was obtained using phase change materials in the single-walled carbon nanotube composition of about 3000 W. The average thermal efficiency of the two heat exchangers as the series has increased by 52%. In general, the effect of the two heat exchangers on each other was investigated in series with two approaches (energy storage and energy conversion) using fin and nanoparticles, which obtained convincing results.
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Rydalina, N. V., B. G. Aksenov, O. A. Stepanov, and E. O. Antonova. "Application of porous materials in heat exchangers of heat supply system." Power engineering: research, equipment, technology 22, no. 3 (September 8, 2020): 3–13. http://dx.doi.org/10.30724/1998-9903-2020-22-3-3-13.
Heat exchange capacity increase is one of the main concerns in the process of manufacturing modern heat exchange equipment. Constructing heat exchangers with porous metals is an advanced technique of heat exchange increase. A construction of heat exchangers with porous aluminum is described in this paper. The first heat transfer agent (hot water) flows through thin copper tubes installed within the porous aluminum. The second heat transfer agent (freon) flows through the pores of aluminum. Laboratory facility was created to study such a heat exchanger. Series of experiments were carried out. The purpose of the research presented here is to create a mathematical model of heat exchangers with porous metals, to perform analytical calculation of the heat exchangers and to confirm the results with the experimental data. In this case, one can`t use the standard methods of heat exchangers calculation because the pores inner surface area is indeterminate. The developed mathematical model is based on the equation describing the process of cooling the porous plate. A special mathematical technique is used to take into account the effect of tubes with water. The model is approximate but its solution is analytic. It is convenient. One can differentiate it or integrate it, which is very important. Comparison of calculated and experimental data is performed. Divergence of results is within the limits of experimental error. If freon volatilizes inside the heat exchanger, the heat of phase transition has to be taken into account alongside with heat capacity. The structure of the mathematical model makes it possible. The results presented in this paper prove the practicability of using porous materials in heat exchange equipment.
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Zhang, Zhou Wei, Ya Hong Wang, and Jia Xing Xue. "Research and Develop on Series of Cryogenic Liquid Nitrogen Coil-Wound Heat Exchanger." Advanced Materials Research 1070-1072 (December 2014): 1817–22. http://dx.doi.org/10.4028/www.scientific.net/amr.1070-1072.1817.
The research and development situation of liquid nitrogen coil-wound heat exchanger were discussed in view of heat exchange in gas purification field in petrol-chemical industry. The basic designing methods and the multi-stream heat exchange process were illustrated by the cryogenic and high pressure crossing heat exchange equipments of liquid nitrogen coil-wound heat exchanger with multi-stream and multiphase flow, including Three-stream back-cooling heat exchangerin first stage, Four-stream back-cooling heat exchangerin second stage, Five-stream back-cooling heat exchangerin third stage, Multi-stream main back-coolingcoil-wound heat exchanger etc. A series of coil-wound heat exchangers with different mixed fluids and different applications were described. The winding structure characteristics and the work principles of the spiral pipe bundles were elaborated to give references for the scientific design and calculation of coil-wound heat exchanger in cryogenic field. The important research directions and the critical scientific problems were forecasted.
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Fakheri, Ahmad. "Heat Exchanger Efficiency." Journal of Heat Transfer 129, no. 9 (November 16, 2006): 1268–76. http://dx.doi.org/10.1115/1.2739620.
This paper provides the solution to the problem of defining thermal efficiency for heat exchangers based on the second law of thermodynamics. It is shown that corresponding to each actual heat exchanger, there is an ideal heat exchanger that is a balanced counter-flow heat exchanger. The ideal heat exchanger has the same UA, the same arithmetic mean temperature difference, and the same cold to hot fluid inlet temperature ratio. The ideal heat exchanger’s heat capacity rates are equal to the minimum heat capacity rate of the actual heat exchanger. The ideal heat exchanger transfers the maximum amount of heat, equal to the product of UA and arithmetic mean temperature difference, and generates the minimum amount of entropy, making it the most efficient and least irreversible heat exchanger. The heat exchanger efficiency is defined as the ratio of the heat transferred in the actual heat exchanger to the heat that would be transferred in the ideal heat exchanger. The concept of heat exchanger efficiency provides a new way for the design and analysis of heat exchangers and heat exchanger networks.
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Osipov, S. N., and A. V. Zakharenko. "Energy-Efficient Compact Heat Exchangers Made of Porous Heat-Conducting Materials." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 61, no. 4 (July 20, 2018): 346–58. http://dx.doi.org/10.21122/1029-7448-2018-61-4-346-358.
After successful increase of levels of thermal resistances of building enclosing structures, expenses of heat on ventilation of rooms in many cases reached similar magnitudes of indicators of heating in a cold season. Therefore, the development of new efficient heat exchangersheat exchangers of small size is of particular importance. It is possible now to create highperformance thin (of a few centimeters) heat exchangers of such high-porous heat-conducting materials as copper, aluminum, etc. Highly porous materials include porous-permeable structures having an open porosity (with a total pore surface area of more than 50 % in relation to a smooth surface). One of the main conditions for the qualitative use of such high-porous thermal conductive materials is the rapid removal of condensate outside the heat exchange zone without a significant increase in filtration resistance. Thermal calculation of such heat exchangers is based on the criteria of Fourier (Fu) and Predvoditelev (Рd). Various ways of using high-porous heat-conducting materials in the design of heat exchangers are considered. The method of production of the heat exchanger based on the application of porous-permeable material in the channels of the heat exchange part of recuperative devices is presented; the difference of the method is that the heat exchange part is performed of two or more parallel heat exchange plates with spacing between them. It has been found that a significant increase in the energy efficiency of heat exchangers of this type is possible due to the application of even small discontinuities of the heat-conducting layers of high-porous materials so to use the specific features of increased heat exchange of the initial sections with the flowing fluid. One of the main advantages of using air-to-air heat exchangers made of foamed high-heat-conducting material in the climatic conditions of Belarus is freezing resistance.
Dissertations / Theses on the topic "Heat exchangers":
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Kennedy, Ian James. "Investigation of heat exchanger inclination in forced-draught air-cooled heat exchangers." Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601789.
In some industrial air-cooled heat exchangers, such as those in the generating set industry, the flow must turn through 90° after exiting the heat exchanger. In such arrangements, the plenum depths are typically very shallow. Furthermore., the axial fan often operates in the mixed-flow region of the fan characteristic, due to the restrictive nature of the system. These two factors lead to a reduction in the thermal performance of the system. The purpose of this study was to investigate the effect on thermal performance of inclining the heat exchanger relative to the axial fan. It was also important to compare this with simply increasing the plenum depth without inclining the heat exchanger, since inclination itself may increase the mean plenum depth. This was achieved through an isothermal experimental investigation, complemented with a numerical study using CFD. The results showed that as the heat exchanger was inclined, the low velocity core at the centre of the heat exchanger tended to move to one side. The opposite side had increased flow through the heat exchanger due to the inclination. For a mixed-flow fan operating point typical of some industries, it was found that inclination has a negligible effect on the performance of the system, when compared with a baseline case. Increasing the plenum depth also had no significant effect. At the axial fan operating point investigated, it was found that an angle of approximately 30° inclination gave the best performance. Increasing the plenum depth was found to improve the performance more than inclination. The best performing case was the non-inclined case with a plenum depth of 0.65 fan diameters. This gave an increase in flow of2.8% over the baseline case, and a corresponding 1.1 % increase in thermal performance.
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Watkins, Rhodri Evan. "Variable Volume Heat Exchangers." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521071.
Bartuli, Erik. "Optimization of Heat Transfer Surfaces of Heat Exchangers." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401602.
Disertační práce je zaměřena na kovové a polymerní výměníky tepla. Hlavním předmětem zkoumání je optimalizace teplosměnných ploch za účelem zvýšení účinnosti výměníku tepla. Tyto cíle byly dosaženy experimentálně a numericky pomocí modelování v ANSYS. Na základě dosažených výsledků byla rozpracována technologie křížového navíjení polymerních výměníků z dutých vláken. Experimentální zařízení původně určené pro navíjení tlakových nádrží bylo modifikované pro automatizovanou výrobu polymerních výměníků z dutých vláken, ježto může být použita při jejich masové výrobě. Tato práce se také zabývala výměníky tepla pro klimatizační systémy. Byly zkoumány možnosti využití polymerních výměníků z dutých vláken v těchto systémech. Mimo jiné byla provedena studie vlivu cyklického tepelného zatížení standardního kovového žebrovaného tepelného výměníku.
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Hensley, Joshua L. "Direct contact heat exchanger development." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/6002.
Thesis (Ph. D.)--University of Missouri-Columbia, 2007. The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 13, 2008) Vita. Includes bibliographical references.
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Keen, D. J. "Combined convection in heat exchangers." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235252.
Henry, M. P. "Design methodology : Regenerative heat exchangers." Thesis, University of York, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379493.
Van, Aken G. J. "Transient modelling of finned tube heat exchangers /." Title page, contents, abstract and summary only, 1993. http://web4.library.adelaide.edu.au/theses/09ENS/09ensv217.pdf.
Boulares, Jihed. "Numerical and experimental study of the performance of a drop-shaped pin fin heat exchanger." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FBoulares.pdf.
Thesis (Mechanical Engineer and M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2003. Thesis advisor(s): Ashok Gopinath. Includes bibliographical references (p. 73-74). Also available online.
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Adams, Juan Carlos. "Advanced heat transfer surfaces for gas turbine heat exchangers." Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534221.
Bart, Hans-Jörg, and Stephan Scholl, eds. Innovative Heat Exchangers. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-71641-1.
Kakaç, S., A. E. Bergles, F. Mayinger, and H. Yüncü, eds. Heat Transfer Enhancement of Heat Exchangers. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-015-9159-1.
Zohuri, Bahman, and Patrick McDaniel. "Heat Exchangers." In Thermodynamics In Nuclear Power Plant Systems, 319–53. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-13419-2_13.
Zohuri, Bahman. "Heat Exchangers." In Nuclear Energy for Hydrogen Generation through Intermediate Heat Exchangers, 211–45. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-29838-2_6.
Karwa, Rajendra. "Heat Exchangers." In Heat and Mass Transfer, 865–928. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-1557-1_14.
Zohuri, Bahman. "Heat Exchangers." In Application of Compact Heat Exchangers For Combined Cycle Driven Efficiency In Next Generation Nuclear Power Plants, 125–60. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-23537-0_6.
Zohuri, Bahman, and Patrick McDaniel. "Heat Exchangers." In Thermodynamics in Nuclear Power Plant Systems, 317–50. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-93919-3_13.
Zohuri, Bahman, and Nima Fathi. "Heat Exchangers." In Thermal-Hydraulic Analysis of Nuclear Reactors, 433–64. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-17434-1_16.
Cetinbas, Cankur Firat, Burak Ahmet Tuna, Cevat Akin, Selin Aradag, and Nilay Sezer Uzol. "Comparison of Gasketed Plate Heat Exchangers With Double Pipe Heat Exchangers." In ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2010. http://dx.doi.org/10.1115/esda2010-24712.
In this study, a computer program is developed to design and compare gasketed plate heat exchangers with double pipe heat exchangers. The computer program is coded in MATLAB. The user interface of the program is prepared in MATLAB Guide. The program uses hot and cold fluid properties as input data and calculates the characteristics of gasketed plate heat exchangers and double pipe heat exchangers designed for the given conditions. The outputs for gasketed plate heat exchanger design include number of plates, effective area, total heat transfer coefficient, pressure losses, pumping power and cost, whereas, the outputs for double pipe heat exchanger selection are: pump power, total number of hairpins, effective area, pressure drop, total heat transfer coefficient and cost. Correlations selected from literature are used in the program for the analysis. Water is selected as the working fluid to be able to make the comparison. The program compares the heat exchangers based on cost, effective area, and pumping power. The computer program is also used to understand and compare operational behaviors of these two heat exchangers under different operating conditions.
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"Heat exchangers." In CONV-09. Proceedings of International Symposium on Convective Heat and Mass Transfer in Sustainable Energy. Connecticut: Begellhouse, 2009. http://dx.doi.org/10.1615/ichmt.2009.conv.110.
Yang, Chien-Yuh, Chun-Ta Yeh, Wei-Chi Liu, and Bing-Chwen Yang. "Advanced Micro Heat Exchangers for High Heat Flux." In ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2006. http://dx.doi.org/10.1115/icnmm2006-96032.
Owing to the rapid development of semiconductor industry, the heat dissipated from electronic devices increases drastically with increasing device logic gate number and operation speed. The cooling technologies have undergone evolutionary changes from air cooled fin geometry to copper base and vapor chamber heat spreader and to more thorough methods such as forced convective liquid cooling in recent years. Three micro heat exchangers with long offset strip, short offset strip and chevron flow path based on the conventional heat transfer enhancement concepts were designed, fabricated and tested. A straight channel heat exchanger was also made for comparison. The test results show that there is no significant difference of the thermal resistance at various heating power for each heat exchanger. The chevron channel heat exchanger provides the lowest thermal resistance. However, its pressure drop is also the highest. It is approximately 250% higher than that for other three heat exchangers. The offset strip heat exchangers provide better thermal performance than the straight channel heat exchanger does. The performance of heat exchanger with shorter strip is better than that of heat exchanger with longer strip. Further improvement such as optimum strip length design or streamlined strip shape may be applied to reduce its flow pressure drop.
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Khurmamatov, Abdugaffor, Ganisher Rakhimov, and Feruzbek Murtazayev. "Intensifications of heat exchange processes in pipe heat exchangers." In 2021 ASIA-PACIFIC CONFERENCE ON APPLIED MATHEMATICS AND STATISTICS. AIP Publishing, 2022. http://dx.doi.org/10.1063/5.0096336.
Sabharwall, Piyush, Mike Patterson, Vivek Utgikar, and Fred Gunnerson. "NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger." In Fourth International Topical Meeting on High Temperature Reactor Technology. ASMEDC, 2008. http://dx.doi.org/10.1115/htr2008-58197.
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 rationale for considering liquid metals as the working fluid is because of the higher convective heat transfer coefficient. This explains the interest in liquid metals as coolant for intermediate heat exchange from NGNP. 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 of NGNP and inlet of the process heat facility. 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 tradeoff between them. Based on NGNP operational parameters, a heat exchanger analysis with the sodium phase change is presented to show that the heat exchanger has the potential for highly effective heat transfer, within a small volume at reasonable cost.
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Al-Khuliawi, Fawaz A. "Practices in Repairing Heat Exchangers." In ASME 2011 Power Conference collocated with JSME ICOPE 2011. ASMEDC, 2011. http://dx.doi.org/10.1115/power2011-55252.
The Presentation will introduce Saudi Aramco Heat Exchanger Shop practices in repairing Heat Exchangers that are used in Power and petroleum Industries for mainly two types Shell & Tube and Air Cooled Heat Exchangers. The Presentation will illustrate current challenges in repairing heat exchangers through strategic partnership to maintain reliable service to Saudi Aramco Plants operation. Four success cases will be addressed.
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Da Veiga, W. Reinaldo, and Josua Petrus Meyer. "SEMICIRCULAR HEAT EXCHANGERS." In Compact Heat Exchangers and Enhancement Technology for the Process Industries - 2003. Connecticut: Begellhouse, 2023. http://dx.doi.org/10.1615/978-1-56700-195-2.310.
Gruss, Jean-Antoine, Christophe Bouzon, and Bernard Thonon. "Extruded Microchannel-Structured Heat Exchangers." In ASME 2004 2nd International Conference on Microchannels and Minichannels. ASMEDC, 2004. http://dx.doi.org/10.1115/icmm2004-2441.
In the search for more compact air/liquid heat exchangers, one possible way is to increase the heat transfer coefficient and surface area by a decrease of the size of the fluid channels. A practical example could be air/water cross-flow heat exchangers used in cars. These exchangers are designed so that air pressure drop is minimised at a given thermal power exchanged from water to air. In this case, minimisation of the total volume leads to a very thin structure with a large frontal area, with a lot of small and short air channels. This configuration is very inconvenient for most practical applications and also difficult to manufacture at low cost. Using this rationale, we have designed and patented a cross-flow heat transfer surface with microchannels that has such a structure, but can be manufactured industrially at reasonable cost by extrusion either in aluminium or in polymers. Moreover, the arrangement of the heat transfer surfaces is very flexible and allows for different configurations (accordion, serpentine, cylindrical, star...) so that various geometric configurations, adapted to specific applications, can be obtained. The thermo-hydraulic performance of the structure has been simulated using standard correlations and CFD codes. Prototypic structures made by stereolithography have been manufactured in glass reinforced polymer and are currently being tested on a test bench. In order to validate our simulation code, a single structure and an accordion arrangement heat exchanger are under investigation. Compared to classical heat exchangers, our design is superior in flexibility and compactness for air/liquid applications. An additional interest of our design would be to increase performance in humid air cooling applications, since our structure may drain condensates more easily. We are currently looking for a partnership to develop this design for industrial applications.
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Yang, Chien-Yuh, and Wei-Chi Liu. "An Experimental Study on Convective Boiling Heat Transfer in Micro Heat Exchangers." In ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30990.
Attributed to its high heat transfer coefficient, evaporating cooling involving the use of micro heat exchangers is considered a possible thermal management solution for cooling of high heat flux electronic devices. The desire to develop high-performance micro heat exchangers operating in the evaporation regime provides a major motivation for the present work. Methanol evaporated in two micro heat exchangers with chevron flow passages and straight flow passages respectively were tested in the present study. The test results show that the heat transfer coefficient increased with increasing flow rate in both chevron and straight flow passages micro heat exchangers. However, the effect of vapor quality on the heat transfer coefficient in the straight passages heat exchanger is in adverse to that in the chevron passages heat exchanger. The heat transfer coefficient increased with increasing vapor quality in the chevron passages heat exchanger but decreased in the straight passages heat exchanger. The flow visualization through transparent cover heat exchangers showed that the liquid film inside channel is partially dry out in the straight passages heat exchanger. The dryout portion area increased with increasing heating rate and exit vapor quality. This degraded the average heat transfer performance for evaporation in the straight passages heat exchanger. Because of the surface tension effect, the liquid film was dragged at the intersection corner of the upper and lower plate chevron passages. There is no significant dryout portion in the chevron passages heat exchanger. The relation of vapor quality with heat transfer performance in chevron passages heat exchanger is therefore similar to the boiling in a single channel prior to critical heat flux condition.
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Khalil, Ibrahim, Ahmad Abu Heiba, and Robert Boehm. "Comparison of Plate Fin Compact Heat Exchanger Performance." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-66113.
Plate fin heat exchangers (PFHE) are characterized by very close temperature approaches and high thermal effectiveness, large heat transfer area per unit volume, low weight per unit transfer and possibility of heat exchange between many process streams. These advantages are only limited by operating fluid temperatures and pressures. The main target of this paper is to study the performance of plate fin compact heat exchangers and to provide full explanation of previous comparison methods of compact heat exchanger surfaces (plain, strip, louvered, wavy, pin, perforated and vortex) used in plate fin compact heat exchangers. We generalize these methods to identify the advantages and disadvantages of each type of geometry (more than sixty geometries studied) based on required size, entropy generation, pumping power, weight, and cost. The effect of using different surfaces on each side of the heat exchanger and design recommendations are also discussed.
Reports on the topic "Heat exchangers":
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Culver, G. DHE (downhole heat exchangers). [Downhole Heat Exchangers (DHE)]. Office of Scientific and Technical Information (OSTI), November 1990. http://dx.doi.org/10.2172/6304383.
Lewinsohn, Charles. Compact Ceramic Microchannel Heat Exchangers. Office of Scientific and Technical Information (OSTI), October 2016. http://dx.doi.org/10.2172/1344124.
Zhao, Y., M. M. Ohadi, and R. Radermacher. Microchannel Heat Exchangers with Carbon Dioxide. Office of Scientific and Technical Information (OSTI), September 2001. http://dx.doi.org/10.2172/795597.
Radermacher, Reinhard, Daniel Bacellar, Vikrant Aute, Zhiwei Huang, Yunho Hwang, Jiazhen Ling, Jan Muehlbauer, James Tancabel, Omar Abdelaziz, and Mingkan Zhang. Miniaturized Air-to-Refrigerant Heat Exchangers. Office of Scientific and Technical Information (OSTI), May 2017. http://dx.doi.org/10.2172/1358252.
Wu, K. C. Performance of RHIC Refrigerator IV: Heat Exchangers. Office of Scientific and Technical Information (OSTI), May 1996. http://dx.doi.org/10.2172/1119227.
Klett, J. W. Graphite Foam Heat Exchangers for Thermal Management. Office of Scientific and Technical Information (OSTI), June 2004. http://dx.doi.org/10.2172/885604.
Farrington, R. B., and C. E. Bingham. Testing and analysis of immersed heat exchangers. Office of Scientific and Technical Information (OSTI), August 1986. http://dx.doi.org/10.2172/5189076.
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