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1
Guo, Kunpeng. "Optimisation of plate/plate-fin heat exchanger design." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/optimisation-of-plateplatefin-heat-exchanger-design(e019a7a5-4be1-4350-b219-3387fd12f7d1).html.
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With increasing global energy consumption, stringent environmental protection legislation and safety regulations in industrialised nations, energy saving has been put under high priority. One of the most efficient ways of energy reduction is through heat transfer enhancement for additional heat recovery. Applying compact heat exchanger is one of the main strategies of heat transfer enhancement. However, the application of compact heat exchangers is prohibited by the lack of design methodology. Therefore, the aim of this research is to tackle the problem of developing optimisation methodologies of plate/plate-fin heat exchanger design. A mathematical model of plate-fin heat exchanger design is proposed to consider fin type selection with detailed geometry and imposed constraints simultaneously. The concept of mix-and-match fin type combinations is put forward to include all possible fin type combinations in a heat exchanger. The mixed integer nonlinear programming (MINLP) model can be converted to a nonlinear programming (NLP) model by employing continuous heat transfer and pressure drop correlations and considering the basic fin geometric parameters as continuous variables. The whole optimisation is based on volumetric minimisation or capital cost minimisation and completed by CONOPT solver in GAMS. Case studies are carried out to demonstrate the effectiveness and benefits of the new proposed methodology. For plate heat exchangers, the design methodology is developed on the basis of plate-fin heat exchanger methodology, and takes phase change, plate pattern selection, flow arrangement and pressure drop constraints simultaneously. The phase change problem is tackled by dividing the whole process into several subsections and considering constant physical properties in each subsection. The performances of various flow arrangements are evaluated by correction factors of logarithmic mean temperature difference. For two-phase conditions, the heat transfer and pressure drop performance are predicted by continuous two-phase Nusselt number and Fanning friction factor correlations to avoid the MINLP problem. The optimisation is solved by CONOPT solver as well. The feasibility and accuracy of the new proposed methodology is examined by case studies.
2
Pua, Lee M. "Overall optimisation framework for multi-stream plate-fin heat exchanger network synthesis." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506290.
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Shi, Dantong. "Characterizing, Correlating, and Evaluating Swirl Flow and Heat Transfer in Wavy Plate-Fin Channels with Novel Enhancement Attributes." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613742268339123.
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Milko, Michal. "Regenerace tepla a vody při sušení papíru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378497.
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Diploma thesis titled Regeneration of heat and water for paper drying process analyzes use of waste hot air ventilated from drying section of paper mill. Moreover is described detailed design process of recuperation heat exchanger, which should be part of regeneration loop of paper mill. Designed heat exchanger is plate-fin crossflow heat exchanger. For deasign is used – NTU method.
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Супрун, А. В. "Дослідження пластинчасто-ребристих теплообмінників з різними видами насадок." Master's thesis, Сумський державний університет, 2020. https://essuir.sumdu.edu.ua/handle/123456789/81699.
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У роботі виконано тепловий, гідравлічний та конструктивний
розрахунки пластинчасто-ребристого апарату компресорної установки з
трикутною, прямокутною та трапецієвидною насадками. У результаті
розрахунку визначено коефіцієнти тепловіддачі від гарячого та холодного
теплоносіїв, геометричні параметри апарату та втрати тиску в апараті.
Проведено дослідження ефективності цих апаратів з різними видами насадок та
вибрано оптимальний варіант, який працює з найбільшими показниками
ефективності по гарячому та холодному теплоносію. Також було розглянуто
питання охорони праці на компресорному підприємстві, де експлуатуються такі
теплообмінники та виконано розрахунок повітрообміну у виробничому
приміщенні.В работе выполнен тепловой, гидравлический и конструктивный расчеты пластинчато-ребристого аппарата компрессорной установки с треугольной, прямоугольной и трапециевидной насадками. В результате расчета определены коэффициенты теплоотдачи от горячего и холодного теплоносителей, геометрические параметры аппарата и потери давления в аппарате. Проведено исследование эффективности этих аппаратов с различными видами насадок и выбрано оптимальный вариант, который работает с наибольшими показателями эффективности по горячему и холодному теплоносителю. Также были рассмотрены вопросы охраны труда на компрессорном предприятии, где эксплуатируются такие теплообменники и выполнен расчет воздухообмена в производственном помещении.
In the work, the thermal, hydraulic and structural calculations of the lamellar-ribbed apparatus of the compressor unit with triangular, rectangular and trapezoidal nozzles were performed. As a result of the calculation, the coefficients of heat transfer from hot and cold heat carriers, the geometric parameters of the apparatus and the pressure loss in the apparatus were determined. A study of the efficiency of these devices with various types of nozzles was carried out and the optimal option was selected, which works with the highest efficiency indicators for hot and cold coolant. Also, the issues of labor protection at the compressor plant, where such heat exchangers are operated, were considered and the calculation of air exchange in the production room was performed.
6
Barbé, Jean-Patrick. "Modélisation des échangeurs-réacteurs compacts." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0146.
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Le contexte industriel est favorable aux échangeurs-réacteurs catalytiques intensifiés puisqu’ils permettent une diminution des limitations aux transferts de matière et de chaleur comparé aux réacteurs conventionnels. Toutefois, l'industrialisation de ces unités est problématique à cause de l'absence de logiciel d’ingénierie de prédiction et d’optimisation de leurs performances. Afin de construire un tel outil, les écoulements, les transferts de matière interne et externe liés aux réactions catalytiques hétérogènes, les transferts de chaleur convectif, conductif, diffusif et par rayonnement sont d’abord analysés, permettant de formuler des hypothèses simplificatrices. Les phénomènes pertinents identifiés sont ensuite mis en équations pour créer la base physique de ProSec Réaction, le nouveau logiciel de simulation des échangeurs-réacteurs. Ce logiciel est validé par comparaison avec les résultats expérimentaux du pilote de vaporeformage du méthane d'Air Liquide et par confrontation avec des simulations tri-dimensionnelles de celui-ci (CFD). L'excellente adéquation entre les résultats expérimentaux et numériques démontre le potentiel de prédiction du modèle mono-dimensionnel développé. Dans le cas particulier des échangeurs-réacteurs à plaques et ailettes catalytiques (wash-coat), une représentation bi-dimensionnelle discrète est construite et permet de tenir compte des effets thermiques radiaux intrinsèques à ces échangeurs particuliers. Enfin, ProSec Réaction est exploité pour évaluer les perspectives d'optimisation géométrique des canaux de l'échangeur-réacteur du pilote d'Air Liquide. Celles-ci montrent la flexibilité et l'intérêt de ce nouvel outil de simulationIntensified heat exchanger reactors are promising technologies in the current industrial context because of their high potential to significantly reduce heat and mass transfer limitations compared to conventional reactors. However, the absence of simulation software for predicting their performances and optimising their geometry inside a flowsheet is limiting the industrialisation of these units. Preliminary to the development of such a simulation tool, flow characteristics, internal and external mass transfers inherent to heterogeneous catalytic reactions, convective, conductive, diffusive and radiative heat transfers are analysed, allowing the definition of simplifying assumptions. The identified relevant phenomena are then modelled and constitute the physical base of ProSec Reaction, the new heat exchanger-reactor simulation software. This software is validated by comparing the predicted values to the Air Liquide steam reforming pilot plant results and to three-dimensional simulation results as well (CFD). The excellent consistency between numerical and experimental results demonstrates the accuracy and the predictive potential of the developed one-dimensional model. In the specific case of wall-coated plate-fin heat exchanger reactors, a discrete two-dimensional model is built and allows the representation of radial temperature gradients in the material, which are intrinsic to these specific heat exchangers. Finally, optimisation perspectives of the Air Liquide pilot plant heat exchanger reactor channel geometry are evaluated thanks to ProSec Reaction. They demonstrate the flexibility and the benefits of this new simulation tool
7
Hecht, Thomas [Verfasser]. "Static Flow Instabilities in Plate-Fin Heat Exchangers / Thomas Hecht." München : Verlag Dr. Hut, 2014. http://d-nb.info/1051550181/34.
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Toubiana, Ephraïm. "Modélisation et analyse des transferts dans les échangeurs à plaques et ailettes à pas décalés : intensification par optimisation géométrique et génération de vorticité." Thesis, Valenciennes, 2015. http://www.theses.fr/2015VALE0005.
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Ce mémoire de thèse traite de l’analyse, l’intensification et l’optimisation du transfert thermique convectif dans les échangeurs à plaques et ailettes à pas décalés utilisés notamment dans le domaine automobile comme refroidisseurs d’air de suralimentation. Deux approches complémentaires sont abordées dans cette étude : des simulations numériques visant à l’analyse fine locale des caractéristiques de l’écoulement et des mécanismes de transfert, et une modélisation de type nodale permettant une caractérisation globale des performances thermo-aérauliques. Sur la gamme de Reynolds considérée différentes modélisations de la turbulence sont mises en œuvre et comparées. Ainsi des simulations aux grandes échelles (LES) permettent de qualifier des simulations de type RANS classiquement utilisées jusque-là : de fortes différences tant au niveau structuration de l’écoulement qu’au niveau performances globales sont ainsi mises en évidence selon le régime d’écoulement considéré. La mise au point d’un modèle nodal est ensuite abordée dans le but de mener des optimisations de géométries d’échangeurs non-conventionnels à pas décalés. Les différents scénarii d’optimisation considérés montrent l’intérêt de cette approche autorisant l’évaluation d’un nombre élevé de configurations géométriques. Dans une dernière partie une nouvelle géométrie innovante permettant de générer des tourbillons longitudinaux sur ce type d’ailettes est proposée et étudiéeThis thesis deals with the analysis, intensification and optimization of convective heat transfer in offset strip fins (OSF) heat exchangers used, for example, in the automotive field as water-cooled charge air coolers. Two complementary approaches are carried out in this study: CFD simulations to perform local fine analysis of the flow characteristics and transfer mechanisms, and a nodal type modeling allowing calculation of global aerothermal performance. Over the range of Reynolds numbers considered, different turbulence modeling approaches are implemented and compared: Large Eddy Simulations (LES) and RANS simulations which are usually used. The qualification of the RANS models shows that strong differences, both in the flow structure and at the overall performance evaluation level, may beobserved, depending on the flow regime considered. Then the development of a nodal model is presented. It aims at carrying out rapid optimization of geometries of unconventional OSF heat exchangers. The various optimization scenarios considered show the interest of this approach allowing the evaluation of a large number of geometric configurations. In a last part, an innovative new geometry that generates longitudinal vortices on this type of fins is proposed and studied
9
Baldwin, Stephen. "A study of heat and fluid flow phenomena on the gas side of circular-tube plate-fin heat exchangers." Thesis, Coventry University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329038.
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Lin, Kuan-Ting. "Experimental and Computational Study of Novel Plate-Fin-Surfaces for Enhancing Forced Convection Heat Transfer in Compact Heat Exchangers." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623166309984355.
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Al-Azzawi, Huda Jasim Mohammed [Verfasser]. "Numerical Simulation of Heat Transfer and Fluid Flow in Additively Manufactured Plate-Fin Heat Exchangers with Wavy Fins / Huda Jasim Mohammed Al-Azzawi." Hannover : Gottfried Wilhelm Leibniz Universität, 2021. http://d-nb.info/123822203X/34.
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Panse, Satchit Pradip. "A Numerical Investigation of Thermal-Hydraulic Characteristics in Three Dimensional Plate and Wavy Fin-Tube Heat Exchangers for Laminar and Transitional Flow Regimes." Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/panse/PanseS0805.pdf.
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The plate fin-and-tube heat exchangers are used in wide variety of industrial applications, particularly in the heating, air-conditioning and refrigeration industries. In most cases the working fluid is liquid on the tube side exchanging heat with a gas, usually air. The current study is focused on two fin configurations, the plain plate-fin and the wavy-fin. These two fin configurations are numerically investigated in both staggered and in-lined tube layouts. The present investigation ranges from laminar flow regime into the sub-critical or transitional flow regime. The suitability of the eddy viscosity turbulence models for the flow representation in the transitional flow regime is discussed in this study. This study reveals that the flow distinction between plain and wavy fin has a profound influence on the heat transfer and flow friction performance of these configurations when compared on the basis of tube layouts. The obtained results also indicate that the number of tube rows plays an important part for the overall heat exchanger performance and an optimum choice for the number of tube rows must be made in order to achieve the critical balance between high heat transfer performance and low pressure drop. It was observed that for an optimum number of tube rows, increasing the longitudinal or transverse tube pitch causes a decrease in the thermal and hydraulic performance of the heat exchanger. For the transitional flow regime, the k-ω turbulence model was found to be more suitable than the k-ε based turbulence models. This suitability of the k-ω turbulence model was linked to the better near wall treatment by this model as compared to the k-ε based models. The results for the fin pitch study indicated that the decrease in the fin pitch causes a decrease in both heat transfer and flow friction characteristics for the transitional flow regime. The results also suggested that for the transitional flow regime, for an equal wavy height, the thermal and hydraulic performance is increased as the wavy angle is increased. On the other hand, for an equal wavy angle, it is decreased as the wavy height is increased.
13
Wei-hsun, Lee, and 李韋勳. "Heat Transfer Estimation of the Varying Fin material Plate Fin and Tube Heat Exchanger." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/40688344828175040437.
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碩士國立勤益科技大學
冷凍空調系
95
The effects of variation of fin material and tube pitch on the plate finned-tube heat exchanger are studied by numerical method. Five fin materials、two tube diameter、two fin pitches and three tube pitches are investigated. Three rating methods are used in the paper: the first method used the Schmidt approximation equation to iterate the fin efficiency, the second method used the Bessel analysis solution to iterate the fin efficiency, and the third method used the Bessel analysis fin efficiency with Schmidt iterated heat transfer coefficient. The results show that the heat exchanger capacity are not affected by the tube diameter and fin material under the low air velocity（0.51m/s）with small fin spacing and the results of the three heat exchanger capacity calculating method used in the study are all the same. Similar results are shown when the tube pitch is increased under the low air velocity. The heat exchanger capacity calculated by the heat transfer coefficients of the aluminum fin would have much error when the air velocity is high. The discrepancy is caused by the decreased fin efficiency and the tube effect on the heat transfer. The results show that the second calculation method has better result when the fin conductivity is larger than the sample(Aluminum)。The first calculation method has better result when the fin conductivity is lower than the Aluminum. The Bessel solution of the fin efficiency is recommended to be used with the sample heat transfer coefficient in the calculation of the increased tube pitch heat exchanger. This study demonstrate the error of the heat exchanger capacity rated by empirical heat transfer coefficient may be caused by the excluding of the fin material and tube diameter in the calculation.
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Chen, Han-Chiang, and 陳漢強. "The effect of end plate on the louver fin-and-tube heat exchanger." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/31686415438453136397.
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碩士國立勤益科技大學
冷凍空調系
102
The effects of flat end plates on the louver fin-and-tube heat exchanger are studied by numerical simulation. The heat transfer and flow field including the flow efficiency and by-pass factors of the flow under different wind speed in the heat exchangers of 3, 4, 5, and 7 fins and two end plates are shown in the results. The flow field in the heat exchanger channel including the duct and louver directed streams is also shown in the results. The results show that the end plates affect the air volume between fins and the louver-directed flow, the end plates lead to the different heat transfer rate in each fin. The channel near the end plates have smaller air flow by the resistant of the plane end plate to the louver-directed flow, which decrease the fin heat transfer neighboring on it. The heat transfer reduction effect is more evident in the low wind speed. The fins in the middle of the heat exchanger have higher heat transfer due to the increasing air flow directed from the channel near the end plates. The results show that increasing the numbers of the fin between the end plates can make the heat transfer rate of the middle fin in the heat exchanger approaches the results of the ideal fin with periodic boundary conditions which used in the most literatures. But it is seems that 7 fins used in this research is still not enough to simulate the periodic ideal fin, it still has about 13% difference. The research could be a reference to the experimental model design of louver fin-and-tube heat exchangers.
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Chen, Chien-Jung, and 陳建榕. "Surface characteristics on effects of heat transfer and condensate carryover phenomena in plate fin-and-tube heat exchanger." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/14527747486726590922.
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Chienyun, Chen, and 陳建昀. "The Optimized Design of the Thermo-Hydraulic Performance for a Plate Fin and Tube Heat Exchanger." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/2ak5q9.
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碩士國立臺北科技大學
能源與冷凍空調工程系碩士班
105
In recent years,the issue of saving energy and carbon reduction has been paid more and more attention. The heat exchanger is based on the heat transfer between the fluids to achieve the purpose of reducing the load. Plate fin-and-tube heat exchagers are widely used in several areas, such as heating, ventilating, air conditioning and refrigeration system. However, the geometries of plate fin and tube heat exchanger influence the flow field characteristics greatly and are the main reason for determining the effectiveness of the heat exchanger. In this study, the heat transfer performance and pressure drop of the air side are simulated by using Computational Fluid Dynamics,CFD. The turbulence model is simulated by k-ω and the simulation results are compared with literature. According to the comparison of results, the reasonable agreement is found between the simulation and experimental data, revealing the accuracy of the CFD simulation. For the purpose of optimizing heat exchanger, this research use Taguchi analysis to find the optimal combination of parameters. The geometrical parameters that affect the performance of the heat exchanger, such as tube arrangement, longitudinal pitch, transverse pitch and fin pitch. The increase in the longitudinal pitch and transverse pitch causes a decrease in the heat transfer and pressure drop performance as the flow becomes less compact. The effect of fin pitch on the heat exchanger shows the opposite performance to that of the longitudinal and transverse pitches. According to the results, the optimal combination of parameters is the in-lined configuration, the longitudinal pitch of 38.1mm, the transverse pitch of 35.4mm, and the fin pitch of 1.53mm.
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Hsun, Yen Chang, and 顏昌旭. "A STUDY OF LOCAL CONVECTIVE HEAT TRANSFER COEFFICIENTS ON PLATE FIN OF A FIN-AND-TUBE HEAT EXCHANGER BY THE TRANSIENT HEAT TRANSFER METHOD WITH THERMOCHROMIC LQUID CRYSTALS." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/00887990424438315206.
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碩士國立中山大學
機械工程學系
87
Heat transfer enhancement is one of the most important objectives for heat exchanger design. However, the coefficient of heat exchanger mainly depends on the performance of fin. In the present study, the local convective heat transfer coefficients on the plate fin of a fin-and-tube heat exchanger with different geometrical parameters, including fin pitch of S=D/3.8, D/4.4 and D/5.6, transverse tube pitch of S=2.0D, 2.5D and 3.0D, longitudinal tube pitch of L=1.5D, 2.0D and 2.5D, and Reynolds number range of 2000 to 9300 are studied and described. Experimental models of heat exchangers are constructed according to similarity principles. Complete distribution of local heat transfer coefficients are measured over the full surface of the plate fin of a fin-and-tube heat exchanger by the transient heat transfer method with thermochromic liquid crystal used as the surface thermometer. Software, LCIA (Liquid Crystal Image Analysis), is used to obtain the temporal history of the surface temperature used to determined the local heat transfer coefficient. The results show that the heat transfer coefficient of the plate fin increases with the Reynolds number and the fin pitch. The heat transfer coefficients of the plate fin with transverse tube pitch S=2.0D is similar to the case with S=2.5D, and is larger than the case with S=3.0D. The heat transfer coefficients of the plate fin with longitudinal tube pitch L=1.5D is similar to the case with L=2.0D, and is smaller than the case with L=2.5D. Therefore, there should exist an optimum geometry of the plate fin for a fin-and-tube heat exchanger.
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WU, KAI-XIANG, and 吳凱翔. "Effect of the angle of attack and position of the vortex generator on the performance of the plate-fin-tube type heat exchanger." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/975847.
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碩士逢甲大學
機械與電腦輔助工程學系
107
In this study, the numerical software ANSYS_FLUENT was used to investigate the influence of the angle of attack and position of the vortex generator on the heat transfer performance of the plate-fin-tube type heat exchanger. The author intended to study the angle of attack of the vortex generator from 15° to 75°, and has planned to change the horizontal position and the vertical position of the vortex generator. In this study, the velocity vector diagram, temperature profile, pressure profile, average heat convection coefficient along the flow direction, and overall average heat convection coefficient were used to investigate the variation of various parameters on the performance of the plate-fin-tube type heat exchanger. It can be inferred from the research results that the difference in the angle of attack of the vortex generator has a great influence on the heat transfer performance. The heat transfer performance is best at an angle of attack of 60°, and the pressure drop increases with an increase in the angle of attack. As for the placement position of the vortex generator, there is a significant influence on the heat transfer effect. When the author changed the horizontal placement position, it is found that the vortex generator can effectively destroy the wake behind the circular tube when placed behind the center of the circular tube, thereby improving the heat transfer effect. However, when the author changed the vertical placement position, it has been found that as the vortex generator approaches the circular tube, the flow gap of the fluid between the vortex generator and the circular tube became smaller, and the resistance increased, thereby causing a decrease in heat transfer performance.
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Ceci, David Michael. "Performance evaluation of plate-fin heat exchangers." Thesis, 1987. http://hdl.handle.net/10945/22411.
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Hsieh, Wu-Lun, and 謝武倫. "Three-dimensional Numerical Analysis of Plate-Fin Heat Exchangers." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/41003746414814974596.
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碩士元智大學
機械工程學系
94
This paper has investigated the performance of the plate-fin heat exchangers numerically. The validity of the used CFD software was confirmed first by comparing the obtained numerical results of the fin surface temperature distribution and the region of the condensation on the fin surface with the measured data by previous experiments. The results of this thesis can be used as a guildline of the designers of heat exchangers. The parameters studied in the present work include the relative humidity of the inlet air, the height of the fin, the width of the fin, the space between the fins, the thickness of the fin, the velocity of the inlet air and the base temperature of the fin. From the simulation results, it has been observed that the corresponding fin performance becomes worse with higher relative humidity of the inlet air, lower height of the fin, smaller width of the fin, narrower space between the fins, thinner of the fin, faster velocity of the approaching air and highter base temperature of the fin. It is also found that the most influential parameter is the thickness of the fin.
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Yu, Jui-Ming, and 游瑞銘. "Estimation of Transient Heat-Transfer Characteristics on the Fin of Plate Finned-Tube Heat Exchangers." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/87045963069526482565.
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碩士國立成功大學
機械工程學系碩博士班
95
The present study applies the finite difference method in conjunction with the Laplace transform method, the least-squares method and the experimental temperature data to predict the transient average heat transfer coefficient, transient heat flux and transient fin efficiency on the rectangular vertical fin of one-tube plate finned-tube heat exchangers. It can be found from the previous study that the heat transfer coefficient on the rectangular fin is very non-uniform. Thus the whole plate fin is divided into several sub-fin regions in order to predict the transient average heat transfer coefficient, transient heat flux and transient fin efficiency on the fin from the knowledge of the experimental fin temperature. In order to validate the accuracy of the present inverse scheme, the present study will simulate this problem. The transient heat-transfer characteristics on the rectangular vertical fin of one-tube plate finned-tube heat exchangers can be predicted using the present inverse scheme in conjunction with the experimental measured temperatures. The results show that the transient heat-transfer characteristics will increase with time and slowly approach its corresponding steady state values. Thus it shows that the estimated results of the present inverse scheme have good reliability and accuracy.
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Chih-HanLu and 呂致翰. "Effect of Flow Model on Heat Transfer Characteristics of Staggered Plate Fin and Tube Heat Exchangers." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/81865369786590343759.
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碩士國立成功大學
機械工程學系碩博士班
101
The present study applies the experimental and numerical inverse methods to predict the average heat transfer coefficient and heat transfer coefficient under the isothermal situation on a vertical square fin of the four-tube plate finned-tube heat exchangers for staggered arrangements and various tube pitch, fin spacings and air velocities, and also investigate the effect on heat transfer characteristics by using another fan behind the fins. These tubes may not have the same temperature in the present study. Due to the non-uniform distribution of the heat transfer coefficient, the whole plate fin is divided into several sub-fin regions before performing the inverse scheme, and the average heat transfer coefficient on each sub-fin region is assumed to be unknown. Later, the inverse scheme of the finite difference method in conjunction with the Least squares scheme and experimental measured temperatures is applied to determine the present results. Results show that and in nature convection increase with increasing the tube pitch and fin spacing S. However, and in force convection increase with increasing the , S and air velocity, under both conditions, Due to the increasing tube pitch caused by the increased amplitude becomes smaller with increasing distance between tube. So present study shows the larger tube pitch the better heat dissipation we have. Other findings are that the average heat transfer coefficients in the upstream and wake fin regions of the 2nd row may be generally lower than these on other sub-fin regions, so we use the outlet fan to improve this problem. In order to validate the accuracy and reliability of the present results, the values are compared with those obtained from the existing correlations or computational fluid dynamics commercial code. Besides, the present study also applies the commercial software, Fluent, in conjunction with the present experimental data to obtain the inter-fin flow field of the plate finned-tube heat exchanger and temperature measurements at various measurement locations of the fin.
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Jian-RongLai and 賴健榮. "Study of Heat-transfer Characteristics on the Fin of Four-tube Plate Finned-tube Heat Exchangers." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/09192653323810477974.
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Pin-ChunChen and 陳品君. "Study of Heat Transfer Characteristics of Plate Fin and Tube Heat Exchangers with Various Tube Arrangements." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/41431584111054163741.
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碩士國立成功大學
機械工程學系
103
The present study applies the inverse method and computational fluid dynamics commercial software in conjunction with the experimental method to predict the heat transfer and fluid flow characteristics of plate-finned tube heat exchangers. The effects of parameters such as air velocity, fin spacing and tube diameter are examined. Due to the heat transfer coefficient on the fin is non uniform, the fin is divided into several sub-regions. Later, the inverse method applies finite difference method in conjunction with the least-squares scheme and the experimental data to estimate the heat transfer coefficient on the fins. More accurate results can be obtained if the heat transfer coefficient is close to the inverse results and matches the existing correlations. The results obtained using the RNG k-ε turbulence flow model for the tube diameter being 27 mm and the laminar model for the tube diameter being 2 mm is more accurate. It means the importance of flow model is negligible, and the number of grid points may also need to change with the air velocity. Therefore, the present study applies different flow models with appropriate grid points to obtain the fin temperature, heat transfer coefficient, air velocity and pressure distribution. Furthermore, the heat transfer coefficient, friction factor and the pressure drop of the big tube diameter is larger than the small tube diameter. The increases friction factor is about 153％ to 277％.
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Yung-ShiangLin and 林詠翔. "Study of Heat Transfer Characteristics for Vertical Plate Fin and Tube Heat Exchangers with Different Tube Diameters." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/52658444325977769888.
Full textAbstract:
碩士國立成功大學
機械工程學系
104
The present study applies the inverse method and CFD software in conjunction with the experimental method to predict the heat characteristics of plate-fin and tube heat exchangers. The effects of parameters such as fin pitch, air velocity and tube diameter are examined. Since the heat transfer coefficient on the fin is not uniform, the fin is divided into several sub-regions and the heat transfer coefficient in each sub-regions is assumed to be a constant. Later, the inverse method applies finite difference method in conjunction with the least-squares scheme and the experimental data to estimate the heat transfer coefficient on the fins. Furthermore, how to choose the appropriate flow model and the effect of grid points are also investigated. Velocity, temperature and heat transfer coefficient distributions of the fin are determined using the CFD software. More accurate results can be obtained if the heat transfer coefficient is closed to the inverse results and matches the existing correlations. The results obtained using the RNG-k-ε turbulence flow model are more accurate for natural convection and mixed convection.
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Lin, Chih hao, and 林志浩. "The Effect of Thermal Conductivity of Plate Fin on Convection Heat Transfer in a Finned-Tube Heat Exchangers." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/41663699784369849549.
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Liu, Young-Chang, and 劉永銓. "Performance of Plate Fin-and-Tube Heat Exchangers – Heat transfer and Frictional Performance Analysis of Larger Diameter Configurations." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/08266199092872248747.
Full textAbstract:
碩士國立雲林科技大學
機械工程系碩士班
94
In the present study, nine plate fin-and-tube heat exchangers were tested. In the geomorphic diameter of heat exchangers, the corresponding longitudinal tube pitches and transverse tube pitches for the tested samples were 33 mm and 38.1 mm, respectively. The nominal tube diameter for all the samples were 15.8mm, and there are three different types of the number of tube rows and fin pitches including 2, 4 and 8-rows and 2.12 mm, 2.54 mm and 3.17 mm for fin pitches. The effect of the number of row and fin pitches of the air-side heat transfer and friction performance were experimentally investigated. According to results, it was found that the fin pitch has negligible effect on both heat transfer and friction factor in 2 and 4 rows heat exchangers. However, it was observed the Colburn j-factor at low Reynolds numbers drops down for plate fin-and-tube exchangers at lager number of tube row and smaller fin pitch form this experiment that is the same with Wang’s definition of Maximum phenomena. The lowest j factor compared with the highest within 80% , the mean deviation of j is between 10~30% and f is between 0~20%. A correlation for fin-and-tube heat exchanger having plain geometry is proposed in this study. We provided a correct factor to upgrade the development correlation. A total of 83 samples containing approximately 739 points for j factor and 593 points for f factor were included the new correlation. The proposed j factor can describe 89.6% of the database within +15%, while the proposed f factor can correlate 86.7% of the database within +15%. The mean deviation of Colburn factor is 7.47 %, and friction factor is 8.22%.
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Chou, Jui-Che, and 周睿晢. "Prediction of Heat Transfer Coefficient on the Fin of Plate Finned-Tube Heat Exchangers with Experimental Temperature Data." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/06270862679409770153.
Full textAbstract:
碩士國立成功大學
機械工程學系碩博士班
93
The present study applies the finite difference method in conjunction with the least-squares scheme and the experimental temperature data to predict the average convection heat transfer coefficient and the fin efficiency on the rectangular vertical fin of one-tube plate finned-tube heat exchangers. The heat transfer coefficient on this rectangular fin is very non-uniform. Thus the whole plate fin is divided into several sub-fin regions in order to predict the average heat transfer coefficient and the fin efficiency on the fin from the knowledge of the experimental fin temperature. A plate finned-tube evaporator and some relative experimental equipments and set up in order to measure the fin temperature. The heat transfer coefficient can be predicted by using the present inverse scheme according to the temperature measurements on the fin. The results show that the heat transfer coefficient on the upstream region of the fin can be markedly higher than that on the downstream region in mixed convection. However, the average heat transfer coefficient will approach a fixed value under the free convection provided the fin spacing is larger than 0.002m. In order to evidence the accuracy of the present inverse scheme and the reliability of the some experimental formulas, a comparison of the average heat transfer coefficient between the present predicated results and the previous results in Heat Transfer Textbook is made.
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Shi-WeiZhan and 詹士緯. "Comparative Study of Heat Transfer Characteristics for Elliptic Tube and Plate Fin Heat Exchangers in Staggered Two-Row Arrangements." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/82832370901698604839.
Full textAbstract:
碩士國立成功大學
機械工程學系碩博士班
100
The present study applies the numerical inverse method and experimental method to predict the average heat transfer coefficient and heat transfer coefficient under the isothermal situation on two kinds of elliptic tubes and plate-finned heat exchangers for two-row staggered arrangements in different fin spacings and air velocities. Due to the non-uniform distribution of the heat transfer coefficient, it must divide the plate fin into several sub-fin regions before performing the inverse scheme, and the unknown average heat transfer coefficient on each sub-fin region is required. Next step, the inverse scheme of the finite difference method in conjunction with the Least squares scheme and experimental measured temperatures is applied to determine the present results. Another important result of the study is that and in nature convection increase with increasing the fin spacing S but it tends asymptotically towards a certain limiting or final value. However, and in force convection increase with increasing the fin spacing S and air velocity. The lower average heat transfer coefficients concerned with the upstream and wake fin regions of the 2nd row, The concentrated elliptic tube of staggered plate-finned may increase the pressure drop. A computational fluid dynamics ( CFD ) program called Fluent for verifying the Reliability is used in the analysis.
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Huang-ChiaTseng and 曾竑嘉. "Numerical and experimental study on natural convection heat transfer characteristics of plate finned tube heat exchangers with various fin shapes." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/hm65p5.
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Yuan, Ping, and 袁平. "Thermal Analysis of Plate-Fin Crossflow Heat Exchangers Including Three Fluid Streams with Different Arrangements and Longitudinal Wall Conduction." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/35665010396905671148.
Full textAbstract:
博士大同工學院
機械工程研究所
87
This study investigates the thermal performance of three fluid streams that flow into a single-pass, plate-fin, crossflow heat exchanger with and without longitudinal wall conduction in three different arrangements. By using the numerical method, the present study discretizes the governing equations into the finite difference equations in each arrangement and then calculates the exit mean temperature of each fluid stream in each arrangement. Meanwhile, this study considers four types of inlet conditions in arrangement 3 by changing the position of fluid stream 1 and fluid stream 3 as well as mixing both the fluid streams. According to the results, it indicates that the suitable choice with different types is I, II, and III in sequence. In addition, this study focuses to analyze the effect of longitudinal wall conduction in arrangements 1 and 3 by defining a deterioration factor. The results show that the wall conduction deteriorates the thermal performance of each fluid stream in both arrangements 1 and 3. Besides, the effect of longitudinal wall conduction on the thermal performance for each fluid stream is evident and it increases with the increase of NTU when both the heat capacity rate of fluid streams 1 and 3 are half of that of fluid stream 2 in arrangement 1. Then, under the same flow and thermal conditions, this study compare the thermal performance among these three arrangements based on the exit mean temperature of fluid streams 1 and 3 as well as temperature difference between inlet and exit mean temperatures of fluid stream 2. The results indicate that the first arrangement has the best uniformity for preheating when both the heat capacity rates of fluid streams 1 and 3 are same and the third arrangement has the best overall ability of heat exchange for all cases. Besides, based on the deterioration factor, the effect of longitudinal wall conduction among these three arrangements is compared with one another under the same flow and thermal conditions. The results show that the deterioration effect on fluid stream 3 is more severe in the first and the third arrangements. Finally, in the view of irreversibility, this study calculates the entropy generation for each arrangement and compares them in the figures of Ns versus NTU1. The results indicate that the third arrangement has the least entropy generation. In other words, the third arrangement has the best quality of thermal energy transformation.
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Wang, Hung-Chih, and 王宏志. "Application of the Inverse Scheme with Experimental Temperature Data to Estimate Heat Transfer Performance on a Wet Fin of Plate Finned-tube Heat Exchangers." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/83769153636246096864.
Full textAbstract:
碩士國立成功大學
機械工程學系碩博士班
94
The present study applies the finite difference method in conjunction with the least-squares scheme and measured temperatures to predict the average convection heat transfer coefficient, total heat rate, and fin efficiency on the rectangular vertical wet fin of plate finned-tube heat exchangers for various air speeds and relative humidities. The least-squares minimization technique is applied to correct the present estimates until the sum of the squares of the deviations between the calculated and measured temperatures are minimum in the present study. In order to show the reliability of the present estimates, the present study will apply the 1-D inverse heat conduction problem to perform the inverse analysis. A comparison between the present estimates and the previous results is made. The results show that the heat transfer coefficient and the heat rate on the fin increases with the relative humidity, but the fin efficiency decreases with increasing the relative humidity. In order to investigate the heat transfer performance on a fin of plate finned-tube heat exchangers further, the 2-D inverse heat conduction problem is also applied to determine the present estimates. The present estimates obtained from the 2-D inverse analysis compare with those obtained from the 1-D inverse analysis.