Heat Transfer最新文献_第10页

Weakly nonlinear analysis of Darcy–Brinkman gravity modulated biothermal convection in rotating porous media 旋转多孔介质中Darcy-Brinkman重力调制双热对流的弱非线性分析

IF 2.8

Heat Transfer Pub Date : 2024-10-09 DOI: 10.1002/htj.23205

P. A. Akhila, B. Patil Mallikarjun, Palle Kiran

{"title":"Weakly nonlinear analysis of Darcy–Brinkman gravity modulated biothermal convection in rotating porous media","authors":"P. A. Akhila, B. Patil Mallikarjun, Palle Kiran","doi":"10.1002/htj.23205","DOIUrl":"https://doi.org/10.1002/htj.23205","url":null,"abstract":"The present study investigates the gyrotactic microorganism flow in a rotating porous medium containing Newtonian fluid. Using gravity modulation, Darcy–Brinkman biothermal convection is examined. Linear theory describes the stationary convective mode which derives the expression for critical Rayleigh number. This indicates the onset of bioconvection. The system's marginal stability is demonstrated by graphical and tabular representation which has a good agreement with each other. The Ginzburg–Landau equation governs the Nusselt number, which is used to further explore heat transfer. The study provides an explanation and graphical representation of the effects of the following factors on heat transfer: cell eccentricity, modified Vadasz number and bioconvective Rayleigh–Darcy number, modulation frequency, and amplitude along with Taylor number. The mean Nusselt number has been plotted in the current study. The effect of rotating porous media and gravity modulation is explained in this work. Additionally, a comparison graph is plotted to examine the effects of gravity, both modulated and unmodulated, on the Nusselt number. This demonstrates how well gravity modulation on rotating porous media controls the system's heat transfer. A comparison between numerical and analytical results for unmodulated cases is also explained graphically.","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 1","pages":"968-993"},"PeriodicalIF":2.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental study on the effects of integrating phase change material with a solar updraft tower 相变材料与太阳上升气流塔集成效应的实验研究

IF 2.8

Heat Transfer Pub Date : 2024-10-09 DOI: 10.1002/htj.23207

Ali Abdulrahman Qasim, Munther Abdullah Mussa

{"title":"Experimental study on the effects of integrating phase change material with a solar updraft tower","authors":"Ali Abdulrahman Qasim, Munther Abdullah Mussa","doi":"10.1002/htj.23207","DOIUrl":"https://doi.org/10.1002/htj.23207","url":null,"abstract":"The solar updraft tower power plant presents a promising renewable energy solution but faces limitations in thermal efficiency and energy production during nonsunny hours. This study addresses a critical gap in the literature by investigating the integration of latent heat storage systems utilizing paraffin wax as phase change materials (PCMs) to enhance solar updraft tower (SUT) performance. Two identical small-scale SUTs were constructed, both using the same tank configuration; however, the PCM device was filled with paraffin wax as a PCM, while the non-PCM device contained only atmospheric air. Three scenarios were explored, featuring varying PCM tank heights of 2, 4, and 6 cm (the full capacity of the PCM tank). Results indicated that, from 3 p.m. until sunset, the PCM-integrated SUT in Case 3 (with 6 cm of PCM) achieved the best performance, with an average absorber temperature rise of 25°C, compared with 12°C for the non-PCM device. During the same period, the average air velocity at the tower neck, where a wind turbine could be installed, was 1.21 m/s for the PCM device, versus 0.82 m/s for the non-PCM device. Notably, the nocturnal operating time extended significantly with PCM use, rising from 90 min for the 2 cm case to 125 min for the 6 cm case. In contrast, the non-PCM device exhibited no operational time after sunset. This research not only demonstrates the effectiveness of PCM in improving the thermal performance and operational longevity of SUTs but also introduces a novel tank configuration that allows for flexible PCM integration, representing a significant advancement in the development of more efficient SUT systems.","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 1","pages":"994-1013"},"PeriodicalIF":2.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of Brownian motion and thermophoresis in magnetohydrodynamic dissipative: Radiative flow of chemically reactive nanoliquid thin films on an unsteady expandable sheet in a composite media 磁流体耗散中布朗运动和热电泳的影响：复合介质中化学反应纳米液体薄膜在非定常可膨胀片上的辐射流动

IF 2.8

Heat Transfer Pub Date : 2024-10-07 DOI: 10.1002/htj.23203

Dulal Pal, Debranjan Chatterjee

{"title":"Impact of Brownian motion and thermophoresis in magnetohydrodynamic dissipative: Radiative flow of chemically reactive nanoliquid thin films on an unsteady expandable sheet in a composite media","authors":"Dulal Pal, Debranjan Chatterjee","doi":"10.1002/htj.23203","DOIUrl":"https://doi.org/10.1002/htj.23203","url":null,"abstract":"This study comprehensively examines magnetohydrodynamic heat transport characteristics within a thin nanofluid film on a stretchable sheet embedded in a composite medium. By considering factors such as the unsteady nature of sheet velocity, Brownian motion, thermophoresis, thermally radiative heat, irregular heat generation/sink, chemical reactions, and dissipation due to viscous fluid, the research provides valuable insights into the variations in fluid velocity, temperature, and nanoparticles concentration. The computational solution utilizes the efficient numerical method that enables accurate predictions of system behavior under varying conditions. Notable findings include the influence of Schmidt numbers on nanoparticle concentration distribution, the opposing impact of thermophoresis parameter values, and the influence of Brownian motion and heat source/sink on temperature profiles in thin nanofluid film. Also, nanoliquid film thickness is reduced by enhancing the porous parameter values and Hartmann number values. The nanoliquid film becomes thinner when the space-dependent heat source/sink parameter is considered compared to the temperature-dependent heat source/sink coefficient. In space-dependent and temperature-dependent cases, the increase in these parameters leads to a decrease in the temperature gradient. Furthermore, it is observed that higher thermophoresis values correspond to reduced nanoparticle concentration gradient profiles. Also, enhancement in the chemical reaction values leads to an expansion in the solutal boundary region surrounding nanoparticles, and as a consequence, the concentration gradient of nanoparticles is enhanced. This research has significant potential for optimizing heat performance and advancing innovation in industrial and engineering processes.","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 1","pages":"941-967"},"PeriodicalIF":2.8,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical analysis of the combined influence of fin shape and location on constrained melting of phase change materials in a spherical capsule with double fins 翅片形状和位置对带有双翅片的球形胶囊中相变材料受限熔化的综合影响的数值分析

IF 2.8

Heat Transfer Pub Date : 2024-10-07 DOI: 10.1002/htj.23196

Akhalesh Sharma, Rohit Kothari, Vivek Saxena, Santosh Kumar Sahu

{"title":"Numerical analysis of the combined influence of fin shape and location on constrained melting of phase change materials in a spherical capsule with double fins","authors":"Akhalesh Sharma, Rohit Kothari, Vivek Saxena, Santosh Kumar Sahu","doi":"10.1002/htj.23196","DOIUrl":"https://doi.org/10.1002/htj.23196","url":null,"abstract":"This study presents a novel approach to investigating the combined influence of fin position and shape on the constrained melting behavior of phase change material (PCM) within a spherical capsule (S.C.) through numerical analysis. Unlike previous research, which predominantly focused on single fin shapes or positions, this work uniquely explores the impact of double, simple, and easily manufacturable fin shapes. A two-dimensional computational model employing the enthalpy–porosity method assesses melting behavior, temperature distribution, and PCM flow. Numerous fin shapes, namely rectangular, trapezoidal converging, trapezoidal diverging stepped, inverse stepped, and triangular, are considered in the analysis. The study reports the influence of the location of two identically shaped fins on the thermal performance. The fins' cross-sectional area and base thickness are kept equal in all cases. The thermal performance of an S.C.-integrated fin system is evaluated by analyzing various attributes such as total saving in the duration of melting, enhancement ratio, and Nusselt number. The results indicate that the position of the fins has a more significant impact on melting performance than the fin shape. The best performance is achieved when fins are placed in the lower half of the capsule, followed by the center and upper halves, regardless of fin shape. For rectangular fins, shifting the position of the fin from the bottom half to the center increases the melting time by 24.7% and the top half by 68.3%. The shortest melting time of 93 min is observed for lower-half rectangular fins, followed by center-placed triangular fins (94 min). This study offers a theoretical foundation for optimizing the performance of different technologies using latent heat thermal energy storage systems such as packed-bed, cascaded thermal energy storage systems.","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 1","pages":"904-940"},"PeriodicalIF":2.8,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical analysis of Soret/Dufour MHD convection in a NEPCM-filled cavity with partial porous foam: Double pipe heat exchanger application Soret/Dufour MHD对流在nepcm填充部分多孔泡沫腔中的数值分析：双管换热器的应用

IF 2.8

Heat Transfer Pub Date : 2024-10-03 DOI: 10.1002/htj.23185

Mohammed Azeez Alomari, Ahmed M. Hassan, Qusay H. Al-Salami, Farah Q. A. Alyousuf, Muneer A. Ismael, Faris Alqurashi, Mujtaba A. Flayyih

{"title":"Numerical analysis of Soret/Dufour MHD convection in a NEPCM-filled cavity with partial porous foam: Double pipe heat exchanger application","authors":"Mohammed Azeez Alomari, Ahmed M. Hassan, Qusay H. Al-Salami, Farah Q. A. Alyousuf, Muneer A. Ismael, Faris Alqurashi, Mujtaba A. Flayyih","doi":"10.1002/htj.23185","DOIUrl":"https://doi.org/10.1002/htj.23185","url":null,"abstract":"The current work extensively investigates double-diffusive of nano-encapsulated phase change material in a thermal storage system partially filled with porous foam. The generation of irreversibilities and the influence of Soret/Dufour and magnetohydrodynamic effects are also considered. The circular cold cavity contains a corrugated hot cylinder covered by an annular foam. The considered parameters are Rayleigh number (103–105), fusion temperature (0.1–0.9), Stefan number (0.1–0.9), volume concentration of nanoparticles (0–0.05), Darcy number (10−4–10−1). Hartmann number (0–80) and the undulations of the inner (3–9). The numerical analysis has exploited the finite element approximations. The results indicate that Rayleigh and Hartmann numbers greatly influence the fluid flow, isotherms, concentrations and the melting/solidification region. The fusion has also a great influence on the melting/solidification region while there is no evident influence on the flow, isotherms and the concentrations where both Nusselt and Sherwood numbers change with around 5% with the change of the fusion temperature and Stefan number. In contrast, both values are decreased by around 30% by decreasing the Da number from 0.1 to 10−4. Furthermore, the change of the undulations number has very low influence on heat transfer, mass transfer and the melting/solidification region.","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 1","pages":"788-830"},"PeriodicalIF":2.8,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Field study of a cubical integrated solar collector storage tank under Baghdad province 巴格达省地下立方体集成太阳能集热器储罐的实地研究

IF 2.8

Heat Transfer Pub Date : 2024-10-03 DOI: 10.1002/htj.23183

Karima E. Amori, Sarah O. Al-Tahir

{"title":"Field study of a cubical integrated solar collector storage tank under Baghdad province","authors":"Karima E. Amori, Sarah O. Al-Tahir","doi":"10.1002/htj.23183","DOIUrl":"https://doi.org/10.1002/htj.23183","url":null,"abstract":"A new, easy-to-manufacture, and low-cost integrated cubical solar collector tank for domestic usage is concerned in this work. Three models are prepared, side by side, and tested to point out their seasonal performance. Tank Model I has three vertical sides, black painted and glazed to act as an absorber; the other sides are insulated. Tank Model II has two black painted and glazed sides, with four insulated surfaces. The models are south-oriented at different positions and tested versus the conventional tank (Model III) to validate and assess their performance in summer and winter. In summer, the temperatures in Models I and II are lower than those for Model III since they have insulated sides. Their glazed sides absorb a small amount of solar radiation since they are almost parallel to the incident solar radiation in summer. In winter, the water temperature in these models rises higher than that for Model III since their glazed sides work as solar collectors and have much lower heat loss to ambient. Therefore, the new design can provide a moderate temperature for summer and winter for residential use. Their water temperature does not exceed the ambient temperature at night in summer. It was higher than the ambient temperature in winter. The thermal efficiency for Models I and II in summer was 10.93% and 15.62%, respectively. While in winter, they were 15.09% and 19.46%, respectively.","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 1","pages":"767-787"},"PeriodicalIF":2.8,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study the effect of adding rectangular fins along the riser pipe on the thermal performance of the flat-plate solar water heater system 研究了沿提升管加装矩形翅片对平板太阳能热水器系统热性能的影响

IF 2.8

Heat Transfer Pub Date : 2024-10-03 DOI: 10.1002/htj.23197

Sabaa Theeyzen, Basim Freegah

{"title":"Study the effect of adding rectangular fins along the riser pipe on the thermal performance of the flat-plate solar water heater system","authors":"Sabaa Theeyzen, Basim Freegah","doi":"10.1002/htj.23197","DOIUrl":"https://doi.org/10.1002/htj.23197","url":null,"abstract":"The earlier studies investigated many parameters affecting the flat plate solar collectors (FPSCs) while employing an active approach to transmit the heat transfer fluid and running under a constant heat flux. In contrast, the presented study investigates enhancing the thermal performance through added fins with different heights and numbers to FPSC in a changing heat-flux condition and relies on a passive technique. Thus, Models A, B, and C included adding five fins along the riser-pipe with heights of 5, 7.5, and 10 mm, respectively, while Models D and E used four and three fins of 10 mm height, and the numerical calculations were conducted using ANSYS Fluent 2022R1. Then, the experimental work was done for the traditional model in Baghdad City, Iraq, to validate the results of numerical work, and the numerical and experimental work difference was found to be 10.17% for the tank's average temperature and the heat transfer liquid's temperature at the riser outlet is 10.14%. The numerical results indicate that the thermal efficiency of the system in all test models (A, B, C, D, and E) is enhanced than the classical model regarding the water's temperature in the tank and the working liquid's temperature at the pipe's outlet. In addition, the study concluded that Model C achieved a greater overall thermal efficiency than the traditional model by 38.59% and higher than Models A, B, D, and E by 11.77%, 6.65%, 8.19%, and 18.09%, respectively.","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 1","pages":"831-853"},"PeriodicalIF":2.8,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An analytical study of ohmic dissipation and diffusion-thermo effect on MHD convective flow through an infinite vertical porous plate with constant heat and mass flux 恒热恒质垂直多孔板中MHD对流的欧姆耗散和扩散热效应分析研究

IF 2.8

Heat Transfer Pub Date : 2024-10-03 DOI: 10.1002/htj.23201

Sweety Sharma, Kangkan Choudhury

引用次数: 0

Performance analysis of minichannel heat sink with oblong cavities and diverse pin fin configurations 矩形腔和不同引脚鳍结构的小通道散热器性能分析

IF 2.8

Heat Transfer Pub Date : 2024-10-03 DOI: 10.1002/htj.23198

Ahmed Jamal Mustafa, Ihsan Ali Ghani

{"title":"Performance analysis of minichannel heat sink with oblong cavities and diverse pin fin configurations","authors":"Ahmed Jamal Mustafa, Ihsan Ali Ghani","doi":"10.1002/htj.23198","DOIUrl":"https://doi.org/10.1002/htj.23198","url":null,"abstract":"Passive heat transfer techniques in minichannel heat sinks (MCHS) provide effective thermal management solutions for high heat flux applications. The current study introduces a three-dimensional numerical analysis conducted to explore the flow and heat transfer characteristics of MCHS utilizing two passive techniques: incorporating pin fins with oblong-shaped cavities. Four types of pin fin shapes were developed, including tear-drop (MCOC-TDPF), pyramidal (MCOC-PPF), conical (MCOC-CPF), and oval (MCOC-OPF), respectively. The study is carried out under a laminar flow regime with Reynolds number ranging from 100 to 1000. The overall performance of these designs is assessed through a comparative analysis of traditional MCHS based on average Nusselt number, friction factor, and overall performance factor. Among these designs, MCOC-CPF exhibited superior thermal performance compared to the other three configurations, with a maximum performance factor of 2.25 at a Reynolds number of 1000. Furthermore, the influence of conical pin fin taper ratio (β) on the thermal enhancement of MCOC-CPF is also analyzed. Four values of conical pin fin taper ratio (β) have been considered, namely 1/6, 1/3, 1/2, and 2/3. The results revealed that β = 1/3 achieved an optimal overall performance of 2.39 at Reynolds number Re = 1000.","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 1","pages":"854-882"},"PeriodicalIF":2.8,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Maximal heat transfer density from cross-flow heat exchanger with tapered fins using constructal design method 用结构设计方法计算锥形翅片交叉流换热器的最大换热密度

IF 2.8

Heat Transfer Pub Date : 2024-09-30 DOI: 10.1002/htj.23199

Ahmed Waheed Mustafa

{"title":"Maximal heat transfer density from cross-flow heat exchanger with tapered fins using constructal design method","authors":"Ahmed Waheed Mustafa","doi":"10.1002/htj.23199","DOIUrl":"https://doi.org/10.1002/htj.23199","url":null,"abstract":"Tapered fins are widely used in heat sinks cooled by forced convection. In this study, maximal forced convective heat transfer from a set of tapered fins in cross-flow is investigated based on the constructal design method. The tapering of the fins is done for a three-fin base-to-tip ratio (taper ratio). The first taper ratio is TR = 0.5 (fin base < fin tip), the second taper ratio is TR = 1 (fin base = fin tip, straight fin), and the third taper ratio is TR = 2 (fin base > fin tip). In all these cases, the fin length is constant. The fins are heated at constant surface temperature and they are cooled by cross-flow. A constant pressure difference pushes the cross-flow toward the fins. The Bejan number ranges from 105 to 107. The forced convective heat transfer density is maximized from the fins for the three taper ratios, and a comparison between them is carried out. The maximization is conducted by numerical and scale analysis. In the numerical analysis, the pressure-driven flow equations (continuity, momentum, and energy) are solved by means of the finite volume method. In the scale analysis, two extremes are considered. The first extreme is for TR < 1, and the second extreme is for TR > 1. These two extremes are intersected to find the maximal forced convective heat transfer density. The results obtained from numerical and scale analysis confirmed that the maximal forced convective heat transfer density occurs for straight fins (TR = 1) in the whole range of the Bejan number. The heat transfer density from straight fins (TR = 1) is higher than that of tapered fins (TR = 2) by 45.2%, and it is higher than that of tapered fins (TR = 0.5) by 52.7% at Be = 107.","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 1","pages":"749-766"},"PeriodicalIF":2.8,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142862416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0