Pub Date : 2024-08-01DOI: 10.1615/jenhheattransf.2024053149
Iachachene Farida, Achab Louisa, Cheradi Hanane
In this numerical study, we investigate a novel hybrid consisting of core-shell nanoparticles with a ZnO@Ag structure, with the aim of enhancing heat transfer in non-uniformly heated systems. The numerical analysis spans a diverse set of Rayleigh numbers with a constant nanoparticle density of 0.1%. The results demonstrate significant improvements in Nusselt numbers, with ZnO@Ag nanoparticles, which exhibited a remarkable 20.15% enhancement. This enhancement is attributed to the even coating of materials with superior thermal properties, such as Ag, onto metallic oxides like ZnO, leading to increased overall thermal conductivity. These findings underscore the promising potential of core-shell nanoparticles for enhancing heat transfer in engineering applications, thereby motivating further research and optimization efforts.
{"title":"Enhancing Heat Transfer with New Hybrid Nanofluids type Core@Shell Nanoparticles","authors":"Iachachene Farida, Achab Louisa, Cheradi Hanane","doi":"10.1615/jenhheattransf.2024053149","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2024053149","url":null,"abstract":"In this numerical study, we investigate a novel hybrid consisting of core-shell nanoparticles with a ZnO@Ag structure, with the aim of enhancing heat transfer in non-uniformly heated systems. The numerical analysis spans a diverse set of Rayleigh numbers with a constant nanoparticle density of 0.1%. The results demonstrate significant improvements in Nusselt numbers, with ZnO@Ag nanoparticles, which exhibited a remarkable 20.15% enhancement. This enhancement is attributed to the even coating of materials with superior thermal properties, such as Ag, onto metallic oxides like ZnO, leading to increased overall thermal conductivity. These findings underscore the promising potential of core-shell nanoparticles for enhancing heat transfer in engineering applications, thereby motivating further research and optimization efforts.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":"11 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1615/jenhheattransf.2024053199
Yi-ping Tu, Hsu-Te Lin, Rong-Hua Yeh
A steady, hydrodynamically and thermally fully developed turbulent water flow in internally finned tubes with constant heat flux boundary condition is investigated experimentally. In this experiment, 70°C hot water passes the inner tube while 20°C cold water flows through the annulus passage. In order to eliminate contact thermal resistance, the circular tube having a length of 1400 mm with inner fins is directly milled from a cylinder. Apart from a smooth tube, three internal-finned-tube heat exchanger having 4, 6, and 8 longitudinal trapezoidal fins are tested. For Re=5000, the tested tubes with four, six and eight fins can improve thermal performance by approximately 35.4%, 44.6% and 67.2%, but merely increase friction factor by 1.92%, 4.8% and 6.73%, respectively, compared to a smooth tube. The increases with respect to to a smooth tube in both Nu and f become smaller at a higher Re for N=4, 6, and 8. As pressure drop, increases, Q of the tested finned tubes first grows rapidly, and this growth curve gradually becomes flatter at a higher ΔP. Consequently, the heat transfer performance will become worse as ΔP>3.5 kPa for the proposed heat exchangers. Finally, correlating equations of Nu and f with respect to Re are presented for 3000 ≤ Re ≤ 7250.
实验研究了具有恒定热通量边界条件的内翅片管中稳定、流体力学和热学充分发展的湍流水流。实验中，70°C 的热水流经内管，20°C 的冷水流经环形通道。为了消除接触热阻，长度为 1400 毫米、带有内翅片的圆管是由圆柱体直接铣削而成的。除光滑管外，还测试了三种带有 4、6 和 8 片纵向梯形翅片的内翅片管热交换器。在 Re=5000 的条件下，与光滑管相比，带有 4 片、6 片和 8 片鳍片的测试管分别能将热性能提高约 35.4%、44.6% 和 67.2%，但摩擦因数仅分别增加 1.92%、4.8% 和 6.73%。当 N=4、6 和 8 的 Re 值较高时，与光滑管相比，Nu 和 f 的增加都会变小。随着压降的增加，测试的翅片管的 Q 值首先快速增长，当 ΔP 越大时，增长曲线逐渐变得平缓。因此，当 ΔP>3.5 kPa 时，拟议热交换器的传热性能将变差。最后，在 3000 ≤ Re ≤ 7250 的条件下，给出了 Nu 和 f 与 Re 的相关方程。
{"title":"Experimental Study of Fully Developed Turbulent Flow in Internally Finned Tubes","authors":"Yi-ping Tu, Hsu-Te Lin, Rong-Hua Yeh","doi":"10.1615/jenhheattransf.2024053199","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2024053199","url":null,"abstract":"A steady, hydrodynamically and thermally fully developed turbulent water flow in internally finned tubes with constant heat flux boundary condition is investigated experimentally. In this experiment, 70°C hot water passes the inner tube while 20°C cold water flows through the annulus passage. In order to eliminate contact thermal resistance, the circular tube having a length of 1400 mm with inner fins is directly milled from a cylinder. Apart from a smooth tube, three internal-finned-tube heat exchanger having 4, 6, and 8 longitudinal trapezoidal fins are tested. For Re=5000, the tested tubes with four, six and eight fins can improve thermal performance by approximately 35.4%, 44.6% and 67.2%, but merely increase friction factor by 1.92%, 4.8% and 6.73%, respectively, compared to a smooth tube. The increases with respect to to a smooth tube in both Nu and f become smaller at a higher Re for N=4, 6, and 8. As pressure drop, increases, Q of the tested finned tubes first grows rapidly, and this growth curve gradually becomes flatter at a higher ΔP. Consequently, the heat transfer performance will become worse as ΔP>3.5 kPa for the proposed heat exchangers. Finally, correlating equations of Nu and f with respect to Re are presented for 3000 ≤ Re ≤ 7250.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":"20 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141882032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1615/jenhheattransf.2024053008
Mohab Soliman, Mohamed Shedid, Hala Abd El-Hameed, Hosny Abou-Ziyan
This experimental study investigates the effect of condenser configurations on the thermal performance and operational characteristics of a horizontally rotating heat pipe. The investigated parameters include three condenser lengths (112.5, 150, and 187.5mm), outer condenser conical ends (60, 80, and 100), and inside condenser tapered angles (1, 2, and 3). An experimental apparatus was designed, constructed, and commissioned with nine condenser sections to explore the effect of condenser configuration on the steady-state thermal performance of heat pipes. The heat pipe is tested at a constant speed of 1500 rpm and various heat loads ranging from 25-200 W, using water as the working fluid. Results indicated that under a constant filling charge equals the inside evaporator volume, the best condenser length of the heat pipe equals the evaporator length. On the other hand, under a variable filling charge equals 0.25 the inside pipe volume, the best condenser length equals 1.25 the evaporator length. The condenser with a conical end of 60 enhances the heat pipe performance by about 37.5-60% over the plain condenser. However, the condenser with a tapered angle of 3 produces the best heat pipe thermal performance compared to the conical end or the different-length condensers. The tapered condenser with an angle of 3 enhances the heat pipe thermal conductivity over the plain condenser by 33.3-257.8%. Also, it achieved higher thermal conductivity than the condenser with a conical end of 60 by 16.6-125.0%.
{"title":"Experimental Investigation of the Effect of Condenser Configuration on a Horizontally Rotating Wickless Heat Pipe Performance","authors":"Mohab Soliman, Mohamed Shedid, Hala Abd El-Hameed, Hosny Abou-Ziyan","doi":"10.1615/jenhheattransf.2024053008","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2024053008","url":null,"abstract":"This experimental study investigates the effect of condenser configurations on the thermal performance and operational characteristics of a horizontally rotating heat pipe. The investigated parameters include three condenser lengths (112.5, 150, and 187.5mm), outer condenser conical ends (60, 80, and 100), and inside condenser tapered angles (1, 2, and 3). An experimental apparatus was designed, constructed, and commissioned with nine condenser sections to explore the effect of condenser configuration on the steady-state thermal performance of heat pipes. The heat pipe is tested at a constant speed of 1500 rpm and various heat loads ranging from 25-200 W, using water as the working fluid. Results indicated that under a constant filling charge equals the inside evaporator volume, the best condenser length of the heat pipe equals the evaporator length. On the other hand, under a variable filling charge equals 0.25 the inside pipe volume, the best condenser length equals 1.25 the evaporator length. The condenser with a conical end of 60 enhances the heat pipe performance by about 37.5-60% over the plain condenser. However, the condenser with a tapered angle of 3 produces the best heat pipe thermal performance compared to the conical end or the different-length condensers. The tapered condenser with an angle of 3 enhances the heat pipe thermal conductivity over the plain condenser by 33.3-257.8%. Also, it achieved higher thermal conductivity than the condenser with a conical end of 60 by 16.6-125.0%.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":"263 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1615/jenhheattransf.2024048659
Ketan Yogi, Shankar Krishnan, Prabhu SV
Heat transfer in a flat plate with metal foam under impinging jet conditions is a complex combination of conduction (finned) and convection (unfinned) heat transfer. This study reports an analytical approach for the quantification of finned and unfinned heat transfer from a targeted plate with metal foam under impinging jet conditions. Along with the quantification of heat transfer modes, the interstitial heat transfer, the efficiency of metal foam as a fin, and thermal resistances are also quantified analytically. The analysis is carried out for rectangular slot jet and multiple air jet impingement conditions. The varying parameters are jet to plate spacing, metal foam thickness and Reynolds number. The results suggest that for the slot jet case, the finned and unfinned heat transfer is around 70 and 30 percent of the total heat transfer independent of the foam thickness. However, for multiple jet case, finned and unfinned heat transfer is around 50 percent each except for 12 mm thickness. The interstitial heat transfer coefficient and fin efficiency increase with a decrease in the thickness of the foam. For both slot and multiple jet impingement cases, the thermal resistance to unfinned heat transfer is more in comparison with the finned heat transfer. The presence of metal foam on the flat plate incenses the overall heat transfer by 2 times the smooth flat plate.
{"title":"Finned and unfinned thermal resistances of a metal foam under jet impingement conditions","authors":"Ketan Yogi, Shankar Krishnan, Prabhu SV","doi":"10.1615/jenhheattransf.2024048659","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2024048659","url":null,"abstract":"Heat transfer in a flat plate with metal foam under impinging jet conditions is a complex combination of conduction (finned) and convection (unfinned) heat transfer. This study reports an analytical approach for the quantification of finned and unfinned heat transfer from a targeted plate with metal foam under impinging jet conditions. Along with the quantification of heat transfer modes, the interstitial heat transfer, the efficiency of metal foam as a fin, and thermal resistances are also quantified analytically. The analysis is carried out for rectangular slot jet and multiple air jet impingement conditions. The varying parameters are jet to plate spacing, metal foam thickness and Reynolds number. The results suggest that for the slot jet case, the finned and unfinned heat transfer is around 70 and 30 percent of the total heat transfer independent of the foam thickness. However, for multiple jet case, finned and unfinned heat transfer is around 50 percent each except for 12 mm thickness. The interstitial heat transfer coefficient and fin efficiency increase with a decrease in the thickness of the foam. For both slot and multiple jet impingement cases, the thermal resistance to unfinned heat transfer is more in comparison with the finned heat transfer. The presence of metal foam on the flat plate incenses the overall heat transfer by 2 times the smooth flat plate.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":"26 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141739471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.1615/jenhheattransf.2024053673
Basant Singh Sikarwar
PREFACE
前言
{"title":"Preface: Heat Transfer in Advanced Materials for Sustainable Energy Storage and Conversion","authors":"Basant Singh Sikarwar","doi":"10.1615/jenhheattransf.2024053673","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2024053673","url":null,"abstract":"PREFACE","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":"16 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.1615/jenhheattransf.2024052254
Zhihua Wan, Yanzhong Li
Falling film evaporation has been proposed as a promising alternative to traditional pool boiling heat exchangers due to advantages such as low-pressure drop, heat transfer improvement and refrigerant charge reduction. This paper provides a comprehensive review of recent advancements in falling film flow and heat transfer characteristics, specifically focusing on various surface structures, including smooth plates, corrugated plates, vertical tubes, and horizontal tubes. In the case of film flow on plates, this review highlights key aspects such as film thickness, film wave evolution, wettability, and heat transfer properties. The study further reviews findings on film flow along both the inner and outer surfaces of vertical tubes, as well as horizontal round tubes and non-round tubes. The enhanced tube can be divided into tubes machined with fins and coated with material. Noteworthy findings regarding flow pattern transitions, film thickness, and heat transfer characteristics on horizontal tubes are comprehensively outlined. Furthermore, the impact of external disturbances on film flow and heat transfer is also reviewed. Finally, several challenges and prospective directions for future research are concluded.
{"title":"A review of falling film evaporation under different surface structures and external disturbances","authors":"Zhihua Wan, Yanzhong Li","doi":"10.1615/jenhheattransf.2024052254","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2024052254","url":null,"abstract":"Falling film evaporation has been proposed as a promising alternative to traditional pool boiling heat exchangers due to advantages such as low-pressure drop, heat transfer improvement and refrigerant charge reduction. This paper provides a comprehensive review of recent advancements in falling film flow and heat transfer characteristics, specifically focusing on various surface structures, including smooth plates, corrugated plates, vertical tubes, and horizontal tubes. In the case of film flow on plates, this review highlights key aspects such as film thickness, film wave evolution, wettability, and heat transfer properties. The study further reviews findings on film flow along both the inner and outer surfaces of vertical tubes, as well as horizontal round tubes and non-round tubes. The enhanced tube can be divided into tubes machined with fins and coated with material. Noteworthy findings regarding flow pattern transitions, film thickness, and heat transfer characteristics on horizontal tubes are comprehensively outlined. Furthermore, the impact of external disturbances on film flow and heat transfer is also reviewed. Finally, several challenges and prospective directions for future research are concluded.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":"67 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141257160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Solar Still functions through utilizing solar energy for the process of distilling water. Researchers worldwide are investigating techniques to enhance effectiveness and output of solar stills. The present research is aimed to study variations in different parameters measured during the experimentation of solar still and to analyze the variation of temperature and radiation absorption coefficients for varying water depths. It has been noted that with increase in water level, the maximum temperature achieved within the still decreases. The radiation absorption coefficient with higher water levels, 0.0937 m, is 0.53967 m-1 in comparison to other instances with lower water levels, 0.0625 m, 0.0312 m, and 0.0156 m of radiation absorption coefficient 0.53999 m-1, 0.53999 m-1 and 0.53999 m-1 respectively. The experimentation with a hybrid setup of single slope solar still and a Flat Plate Collector (FPC) (MANIT, Bhopal (23.2599° N, 77.4126° E)) has been used to record for 3 consecutive days during sunshine hours for the month of January. The parameters have been analyzed for a comparative study of convective, radiative, and evaporative heat transfer coefficients.
{"title":"EXPERIMENTATION AND CFD MODELLING OF A SINGLE SLOPE SOLAR STILL","authors":"Shantam Warkad, Jay Mant Jha, Iram Malik, Gaurav Saini, Gaurav Dwivedi, Sundarmurti Suresh","doi":"10.1615/jenhheattransf.2024052793","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2024052793","url":null,"abstract":"The Solar Still functions through utilizing solar energy for the process of distilling water. Researchers worldwide are investigating techniques to enhance effectiveness and output of solar stills. The present research is aimed to study variations in different parameters measured during the experimentation of solar still and to analyze the variation of temperature and radiation absorption coefficients for varying water depths. It has been noted that with increase in water level, the maximum temperature achieved within the still decreases. The radiation absorption coefficient with higher water levels, 0.0937 m, is 0.53967 m-1 in comparison to other instances with lower water levels, 0.0625 m, 0.0312 m, and 0.0156 m of radiation absorption coefficient 0.53999 m-1, 0.53999 m-1 and 0.53999 m-1 respectively. The experimentation with a hybrid setup of single slope solar still and a Flat Plate Collector (FPC) (MANIT, Bhopal (23.2599° N, 77.4126° E)) has been used to record for 3 consecutive days during sunshine hours for the month of January. The parameters have been analyzed for a comparative study of convective, radiative, and evaporative heat transfer coefficients.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":"63 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140831197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Surge in fossil fuels consumption has severely impacted the environment, namely in terms of climate change, due to the influence of extensive pollution. The current study assesses and contrasts the ability of Artificial Neural Networks (ANN), a machine learning technique, and Response Surface Methodology (RSM) derived model to predict the important engine characteristics such as performance and emissions. The effect of parameters such as load (25%, 50%, 75%, and 100%), speed (1500 RPM and 1800 RPM), compression ratio (17.5 and 18.5), and six different blends of diesel-biodiesel fuels (Diesel, SM20, SM40, SM60, SM80, and SM100) were investigated on test engine (4-S single-cylinder DI diesel engine). Box Behnken Design (BBD) of Response Surface Methodology (RSM) and a Multi-Layer Perceptron (MLP) neural network with a topology of 4-10-6 was employed to study the principal engine performance (brake thermal efficiency, brake-specific fuel consumption, and indicated mean effective pressure) and emission (carbon dioxide, nitrogen oxides, and smoke) parameters. Using statistical analysis on both RSM and ANN, the projected outcomes were then compared with experimental results. The outcomes of present study reveals that RSM (Response Surface Methodology) and ANN (Artificial Neural Networks) can be employed to model processes that exhibit high predictability. Optimization can be performed utilizing diverse strategies, which rely on the specific process or problem.
{"title":"Impact of machine learning approach using ANN and RSM to evaluated the engine characteristics of a dual-fuel CI engine","authors":"Chandrabhushan Tiwari, Gaurav Dwivedi, , Tikendra Nath Verma, Anoop Shukla","doi":"10.1615/jenhheattransf.2024052726","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2024052726","url":null,"abstract":"Surge in fossil fuels consumption has severely impacted the environment, namely in terms of climate change, due to the influence of extensive pollution. The current study assesses and contrasts the ability of Artificial Neural Networks (ANN), a machine learning technique, and Response Surface Methodology (RSM) derived model to predict the important engine characteristics such as performance and emissions. The effect of parameters such as load (25%, 50%, 75%, and 100%), speed (1500 RPM and 1800 RPM), compression ratio (17.5 and 18.5), and six different blends of diesel-biodiesel fuels (Diesel, SM20, SM40, SM60, SM80, and SM100) were investigated on test engine (4-S single-cylinder DI diesel engine). Box Behnken Design (BBD) of Response Surface Methodology (RSM) and a Multi-Layer Perceptron (MLP) neural network with a topology of 4-10-6 was employed to study the principal engine performance (brake thermal efficiency, brake-specific fuel consumption, and indicated mean effective pressure) and emission (carbon dioxide, nitrogen oxides, and smoke) parameters. Using statistical analysis on both RSM and ANN, the projected outcomes were then compared with experimental results. The outcomes of present study reveals that RSM (Response Surface Methodology) and ANN (Artificial Neural Networks) can be employed to model processes that exhibit high predictability. Optimization can be performed utilizing diverse strategies, which rely on the specific process or problem.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":"148 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140831200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the thermal management performance of phase change material (PCM) coupled with a microgroove flat plate heat pipe under air cooling and spray cooling conditions. Different ratios of paraffin-lauric acid hybrid PCMs are prepared, and the thermophysical properties of the materials are optimal when the ratio of paraffin-lauric acid is 4:6. Composite PCMs are prepared by adding alumina nanoparticles, and the thermal conductivity is increased by 3.66 times when alumina particles with a mass fraction of 0.6 % are added. Compared to air cooling, the spray cooling system demonstrate up to a 5.7% reduction in peak chip temperature. In the experimental range the spray cooling system dissipates heat better for the 60 W heating power chip, while the air cooling system is more suitable for the 30 W heating power chip. In the air cooling system, the heat stored in the PCM accounts for up to 39.8 % of the heating power. The maximum amount of heat stored in the PCM in the spray cooling system is 37.8 % of the heating power. The heat storage capacity of the PCM in the spray cooling system is slightly lower than that of the air cooling system, but it still has a considerable heat storage capacity. This research can provide ideas for solving the heat dissipation problem of high-density server chips in data centers.
{"title":"Comparison of air-cooled and spray-cooled heat transfer performance with phase change material coupled with microgroove flat plate heat pipe","authors":"Yanpeng Wu, Qianglong Wang, Qianlong Liu, Kaikai Guo, Zisu Hao","doi":"10.1615/jenhheattransf.2024052239","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2024052239","url":null,"abstract":"This study investigates the thermal management performance of phase change material (PCM) coupled with a microgroove flat plate heat pipe under air cooling and spray cooling conditions. Different ratios of paraffin-lauric acid hybrid PCMs are prepared, and the thermophysical properties of the materials are optimal when the ratio of paraffin-lauric acid is 4:6. Composite PCMs are prepared by adding alumina nanoparticles, and the thermal conductivity is increased by 3.66 times when alumina particles with a mass fraction of 0.6 % are added. Compared to air cooling, the spray cooling system demonstrate up to a 5.7% reduction in peak chip temperature. In the experimental range the spray cooling system dissipates heat better for the 60 W heating power chip, while the air cooling system is more suitable for the 30 W heating power chip. In the air cooling system, the heat stored in the PCM accounts for up to 39.8 % of the heating power. The maximum amount of heat stored in the PCM in the spray cooling system is 37.8 % of the heating power. The heat storage capacity of the PCM in the spray cooling system is slightly lower than that of the air cooling system, but it still has a considerable heat storage capacity. This research can provide ideas for solving the heat dissipation problem of high-density server chips in data centers.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":"49 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140802303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.1615/jenhheattransf.2024050377
Kadir Gelis, Kadir Özbek, Taha Mermer
Global population growth and the resulting rapid depletion of energy resources make sustainability of energy resources difficult. By reducing size, weight, and costs, more effective and sustainable systems can be developed and resource consumption reduced. Mini-channel heat exchangers ensure higher heat transfer than macro-channel heat exchangers because of the volume and surface effect factor. Furthermore, the performance of heat exchangers can be increased by suspending nano-sized particles in the base heat transfer fluids. In this study, a concentric mini-tube heat exchanger was designed, manufactured and energy-exergy analyses were made. MWCNT-Water nanofluid prepared at various volume concentrations (0.1%-0.2%-0.3%) and used as a working fluid. The heat transfer performance of the concentric mini-tube heat exchanger was evaluated using the ε-NTU method. The relationship between ε, NTU, Reynolds number, and dimensionless exergy is investigated. Effectiveness (ε), NTU, and dimensionless exergy (e) values were calculated in the range of 5 different Reynolds values (5000-25000) for water and nanofluids prepared at 3 different volumetric concentrations. The use of nanofluids as a working fluid was found to increase the ε and NTU values while decreasing the dimensionless exergy value.
{"title":"ENERGY AND EXERGY ANALYSIS OF DOUBLE PIPE MINI TUBE HEAT EXCHANGER","authors":"Kadir Gelis, Kadir Özbek, Taha Mermer","doi":"10.1615/jenhheattransf.2024050377","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2024050377","url":null,"abstract":"Global population growth and the resulting rapid depletion of energy resources make sustainability of energy resources difficult. By reducing size, weight, and costs, more effective and sustainable systems can be developed and resource consumption reduced. Mini-channel heat exchangers ensure higher heat transfer than macro-channel heat exchangers because of the volume and surface effect factor. Furthermore, the performance of heat exchangers can be increased by suspending nano-sized particles in the base heat transfer fluids. In this study, a concentric mini-tube heat exchanger was designed, manufactured and energy-exergy analyses were made. MWCNT-Water nanofluid prepared at various volume concentrations (0.1%-0.2%-0.3%) and used as a working fluid. The heat transfer performance of the concentric mini-tube heat exchanger was evaluated using the ε-NTU method. The relationship between ε, NTU, Reynolds number, and dimensionless exergy is investigated. Effectiveness (ε), NTU, and dimensionless exergy (e) values were calculated in the range of 5 different Reynolds values (5000-25000) for water and nanofluids prepared at 3 different volumetric concentrations. The use of nanofluids as a working fluid was found to increase the ε and NTU values while decreasing the dimensionless exergy value.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":"138 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140579783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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