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Optimization of Finned-Tube Heat Exchanger in a Gravity-Assisted Separated Heat Pipe
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作者 Yangyiming Rong Weitao Su +3 位作者 Shuai Wang Bowen Du Jianjian Wei Shaozhi Zhang 《Frontiers in Heat and Mass Transfer》 EI 2024年第4期1209-1229,共21页
Finned-tube heat exchanger(FTHE)is often used as an evaporator in commercial products of separated heat pipe(SHP).The working conditions of FTHE in gravity-assisted SHP are significantly different from those working i... Finned-tube heat exchanger(FTHE)is often used as an evaporator in commercial products of separated heat pipe(SHP).The working conditions of FTHE in gravity-assisted SHP are significantly different from those working in refrigerators and air conditioners.Although FTHE is widely used in commercial products of SHP,previous research on its characteristics is very limited.In this paper,a mathematical model for a SHP with FTHE as the evaporator and plate heat exchanger as the condenser is established and verified with experiments.Parametric analyses are carried out to investigate the influences of evaporator design parameters:air inlet velocity,number of tube rows,tube diameter,and fin pitch.With the increasing of air velocity,number of tube rows and tube diameter,and the decreasing of fin pitch,the heat transfer rate increases,while the energy efficiency ratio(EER)decreases monotonically.Using the total cost of the ten-year life cycle as the performance index,the structure parameters of the evaporator with a given heat transfer rate are optimized by the method of orthogonal experimental design.It is found that the total cost can differ as large as nearly ten times between groups.Among the three factors investigated,the number of tube rows has a significant impact on the total cost of the evaporator.With more tube rows,the total cost will be less.The impacts of fin pitch and tube diameter are insignificant.These results are of practical importance for the engineering design of FTHE in gravity-assisted SHP. 展开更多
关键词 Separated heat pipe finned-tube heat exchanger GRAVITY OPTIMIZATION
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Analysis of Thermal Conductivity of Frost on Cryogenic Finned-tube Vaporizer Using Fractal Method 被引量:1
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作者 Shuping Chen Shuting Yao Fushou Xie 《Energy and Power Engineering》 2013年第4期109-115,共7页
Thermal conductivity of frost is not only related to density, but also affected by its microstructure and environmental conditions, and it will continuously change with the formation and growth of frost. Images of fro... Thermal conductivity of frost is not only related to density, but also affected by its microstructure and environmental conditions, and it will continuously change with the formation and growth of frost. Images of frost formation and growth on the cryogenic surface in various shapes at different stages were obtained by experimental measurements, and a numerical simulation of frost formation and growth was carried out based on Diffusion Limited Aggregation (DLA) model of fractal theory in this paper. Based on the frost structure obtained by experiment, the fractal dimension of pore area distribution and porosity of frost layer on the cryogenic finned-tube?vaporizer were calculated by using fractal method, and combined with heat conduction model of frost layer obtained by thermal resistance method, the thermal conductivity of frost on the cryogenic surface was calculated. The result shows that the thermal conductivity calculated by the fractal model coincides with the range of the experimental data. Additionally, comparison with other heat conduction models indicated that it is feasible to introduce the fractal dimension of pore area distribution into heat conduction model to deduce the thermal conductivity of frost. 展开更多
关键词 CRYOGENIC finned-tube VAPORIZER Thermal Conductivity FROST Layer FRACTAL
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Experimental Research on Heat Transfer and Pressure Drop of Two Configurations of Pin Finned-Tubes in an In-line Array
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作者 ShouGuangYao DeShuZhu 《Journal of Thermal Science》 SCIE EI CAS CSCD 1994年第3期167-172,共6页
In this paper, a local simulation method is employed to investigate the heat transfer and pressure dropcharacteristics of two configurations of pin finned tubes deployed in an in-line array. In this research,heat pipe... In this paper, a local simulation method is employed to investigate the heat transfer and pressure dropcharacteristics of two configurations of pin finned tubes deployed in an in-line array. In this research,heat pipes are adopted as heating elements. Therefore, the experimental equipment becomes simpleand has an advantage of sufficient reducibility. The air-side heat transfer and pressure drop correlations for each type of pin fin surface including the effect of the tube-row number are obtained in theReynolds number range commonly encountered in engineering. These correlations may be used in thedesign of pin finned tube heat exchangers. 展开更多
关键词 pin finned-tube heat transfer pressure drop
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CFD performance analysis of finned-tube CO_(2)gas coolers with various inlet air flow patterns
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作者 Xinyu Zhang Yunting Ge Jining Sun 《Energy and Built Environment》 2020年第3期233-241,共9页
A detailed model of three-dimensional computational fluid dynamics(CFD)on a finned-tube CO_(2)gas cooler has been developed and validated.The model is then applied to investigate the effect of uniform and mal-distribu... A detailed model of three-dimensional computational fluid dynamics(CFD)on a finned-tube CO_(2)gas cooler has been developed and validated.The model is then applied to investigate the effect of uniform and mal-distribution inlet airflow profiles on the coil performance.The airflow mal-distribution velocity profiles include linear-up,linear-down and parabolic while the effected coil performance parameters contain airside pressure drop,average airside heat transfer coefficient,approach temperature and coil heating capacity.The model also enables to predict the CO_(2)refrigerant temperature profile along the coil pipes from refrigerant inlet to outlet at different operation conditions.The simulation results reveal that different types of inlet airflow velocity profiles have significant effects on the gas cooler performance.The uniform airflow velocity profile case shows the best thermal performance of gas cooler.Compared with the cases of linear-up and parabolic air velocity profiles,the linear-down airflow profile can influence more on the coil heat transfer performance.Due to the thermal conduction between neighbour tubes through coil fins,reversed heat transfer phenomenon exists which can be detected and simulated by the CFD model.It is predicted that the linear-down airflow profile can increase greatly the reversed heat transfer phenomenon and thus lead to the highest approach temperature and the lowest heating capacity amongst these four types of airflow profiles.The research method and outcomes presented in this paper can have great potentials to optimize the performance of a CO_(2)gas cooler and its associated refrigeration system. 展开更多
关键词 CO_(2)finned-tube gas cooler Airflow misdistributions Heat transfer coefficient CO_(2)refrigeration system Computational Fluid Dynamics(CFD) modelling
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Experimental investigation of enhanced heat transfer for fined circular tube heat exchanger with rectangular fins
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作者 李永星 杨冬 陈听宽 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2006年第4期385-390,共6页
Presents a set of data for flow and heat transfer of finned-tube bundle under the condition of high air flow velocity. Air flow and heat transfer over a 4 × 4 ( columns × rows) finned-tube heat exchanger w... Presents a set of data for flow and heat transfer of finned-tube bundle under the condition of high air flow velocity. Air flow and heat transfer over a 4 × 4 ( columns × rows) finned-tube heat exchanger with rectangular fins was investigated experimentally in a wind tunnel with constant wall temperatures condition. The air flow velocity based on the minimum flow cross-section area over flow channel ranged from 13.8 to 50. 2 m/s, the heal transfer rate ranged from 21.8 to47. 1 kW, and the air temperatures increase ranged from 10. 9 to 19. 8 ℃. The present results were compared with results calculated from correlations proposed by CSPE. For air flow velocity less than 25 m/s, these two results of heat transfer agreed well with each other, whereas for larger velocity, our test data disagreed with the CSPE correlations. For the friction factor, present data are much higher than the predicted results in the whole range. Finally, correlations for friction factors and heat transfer coefficients are DrODosed based on the experimental results. 展开更多
关键词 haeat exchanger rectangular finned-tube enhanced heat transfer friction factor
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3D numerical study and comparison of thermal-flow performance of various annular finne d-tub e designs
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作者 Farouk Tahrour Hijaz Ahmad +3 位作者 Houari Ameur Tareq Saeed Hanaa Abu-Zinadah Younes Menni 《Journal of Ocean Engineering and Science》 SCIE 2023年第3期294-307,共14页
With the increase of heat transfer problems in marine vehicles and submerged power stations in oceans,the search for an efficient finned-tube heat exchanger has become particularly important.The purpose of the present... With the increase of heat transfer problems in marine vehicles and submerged power stations in oceans,the search for an efficient finned-tube heat exchanger has become particularly important.The purpose of the present investigation is to analyze and compare the thermal exchange and flow characteristics between five different fin designs,namely:a concentric circular finned-tube(CCFT),an eccentric circular finned-tube(ECFT),a perforated circular finned-tube(PCFT),a serrated circular finned-tube(SCFT),and a star-shaped finned-tube(S-SFT).The fin design and spacing impact on the thermal-flow performance of a heat exchanger was computed at Reynolds numbers varying from 4,300 to 15,000.From the numerical results,and when the fin spacing has been changed from 2 to 7 mm,an enhancement in the Colburn factor and a reduction in the friction factor and fin performances were observed for all cases under study.Three criteria were checked to select the most efficient fin design:the performance evaluation criterion P EC,the global performance criterion G PC,and the mass global performance criterion M G PC.Whatever the value of Reynolds number,the conventional CCFT provided the lowest performance evaluation criterion P EC,while the SCFT gave the highest amount of P EC.The most significant value of G PC was reached with the ECFT;however,G PC remained almost the same for CCFT,PCFT,SCFT,and S-SFT.In terms of the mass global performance criterion,the S-SFT provides the highest M Gpc as compared with the full fins of CCFT(41-73%higher)and ECFT(29-54%higher).Thus,the heat exchanger with S-SFT is recommended to be used in the cooling of offshore energy systems. 展开更多
关键词 Thermal-flow performance Eccentric fins Star-shaped fins Perforated fins finned-tube designs
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