Heat Transfer最新文献

{"title":"Effect of Interface Bonding on Optimizing the Heat Transfer in Substrate Board With an Array of Heat Sources","authors":"Y. Aditya Varma,&nbsp;N. Rino Nelson,&nbsp;S. P. Venkateshan","doi":"10.1002/htj.23243","DOIUrl":"https://doi.org/10.1002/htj.23243","url":null,"abstract":"<div>\u0000 \u0000 <p>Effective heat distribution in electronic circuitry is essential to improve the performance and life of electronic components such as chips. This study presents a numerical analysis of heat transfer on a substrate board populated with an array of discrete heat sources, assumed to be placed in a horizontal air channel for forced convection cooling. The analysis of electronic packages is performed, taking into consideration the effect of thermal contact conductance (TCC) between the heat source (chip) and the substrate board. The dependence of the temperature distribution on the Reynolds number of air at the inlet and the heating power from the heat source is investigated for inlet velocities ranging from 0.6 to 1.4 m/s and observed to be significant. Temperature and heat transfer coefficient are observed to systematically increase with the increase in the heat dissipation from the heat source. Two configurations—inline and staggered—are analyzed, with the staggered configuration showing superior cooling performance. This improvement is attributed to the fact that staggered arrangements expose fewer heat sources to pre-heated air before it exits the system. Additionally, the location of the heat source reaching the highest temperature is found to be highly dependent on the TCC of the bonding material between the heat source and the substrate. A hybrid optimization strategy is employed, by combining Artificial Neural Network (ANN) and Genetic Algorithm (GA) for optimizing the location of heat sources. ANN is used for predicting the temperature distribution, subsequently followed by GA to minimize the maximum temperature attained by the heat generating source by varying other control variables like TCC thickness, inlet velocity, and heat generation. The thickness of the bonding layer is varied from 0.225 to 0.271 mm and the heat generation is varied from 1000 to 2000 W/m². Among them, TCC is observed to be an important parameter controlling the optimum location of heat generating sources. The results obtained from the proposed hybrid optimization strategy are compared with the simulation results and observed to be reasonably close.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 2","pages":"1574-1588"},"PeriodicalIF":2.8,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143380221","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}

{"title":"Magnetohydrodynamic Natural Convection in a Circular Dome-Shaped Enclosure","authors":"K. Venkatadri","doi":"10.1002/htj.23245","DOIUrl":"https://doi.org/10.1002/htj.23245","url":null,"abstract":"<div>\u0000 \u0000 <p>The design of flow structures plays a crucial role in enhancing natural convective heat transfer within enclosures. By optimizing the geometry of enclosures to influence flow structures, we can significantly improve their natural convective heat transfer performance. Specifically, the dome-shaped wall can alter flow direction, improving flow circulation and natural convection. The current study conducts a numerical investigation of the laminar flow and natural convective heat transfer of air within a dome-shaped enclosure, while also considering the impact of a magnetic field. The analysis encompasses the interaction between magnetic field and buoyancy-driven flow. Governing equations for momentum, energy, and angular momentum are formulated, integrating the influence of the Lorentz force. The working fluid <i>Pr</i> = 0.71 is considered in this study. The equations are transformed into dimensionless form using key parameters, such as the buoyancy number (<i>Ra</i>) and Hartmann number (<i>Ha</i>). The modeled partial differential equations were carried out with a vorticity-stream function algorithm to explore the influence of magnetic field strength on the flow and thermal characteristics. Results indicate significant alterations in flow patterns and temperature distribution behavior under varying magnetic field and Rayleigh number. The interaction between buoyancy and magnetic fields plays a critical role in determining the heat transfer characteristics of an incompressible fluid, with <i>Ra</i> enhancing, and <i>Ha</i> suppressing, convective efficiency. Heat transfer enhancement of 82.84% is noticed for a Rayleigh number ranging from 10³ to 10⁴, while a 48.316% decrement is found for a Hartmann number ranging from 0 to 10 with <i>Ra</i> = 10⁵. The transition from a magnetically dominated regime (high <i>Ha</i>) to a thermally driven regime (low <i>Ha</i>) leads to a shift from a uniform temperature field to one with more complex thermal layering and mixing, which is reflected in the varying shapes and amplitudes of the Nusselt number distributions. At higher <i>Ha</i> values, magnetic forces dominate, significantly suppressing buoyancy-driven convection, and reducing the intensity of thermal mixing.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 2","pages":"1611-1622"},"PeriodicalIF":2.8,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379924","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}

{"title":"Computational Analysis and Experimental Investigation of the Performance of an Evacuated Tube Solar Air Heater Incorporating Therminol-55 as a Thermal Energy Storage Medium","authors":"Adarsh Abi Mathew,&nbsp;Neeta Mandhare","doi":"10.1002/htj.23226","DOIUrl":"https://doi.org/10.1002/htj.23226","url":null,"abstract":"<div>\u0000 \u0000 <p>The evacuated tube solar air heaters (ETSAHs) are gaining popularity today because of their reduced heat loss capability. A performance evaluation of the evacuated tube solar collector (ETSC) using a thermal energy storage (TES) facility was carried out during the study. A new heat pipe (HP) system with a TES unit directly integrated into it was used in the study along with ETSAH. The novel HP system directly stores the thermal energy and is capable of heating the air uniformly from all directions. Therminol-55 (T-55) was the sensible heat storage material integrated inside a common condenser HP system. The solar collector's performance was evaluated at air flow rates ranging from 0.003 to 0.02 kg/s. The HP and T-55 exhibited a maximum temperature of 121°C and 127°C. The highest temperature of the air leaving ETSAH-TES was 128°C. ETSAH-TES delivered hot air over 100°C continuously for 7 h. The results depict that even when solar energy was erratic, the HP developed in this research supplied a continuous hot air flow. The average energy and exergy efficiency achieved was 37.87% and 2.8%, respectively. T-55 can store a maximum of 1920 kJ of energy. With a standard deviation ranging from 0.2% to 1.87%, the ETSC-TES numerical analysis is in excellent agreement with experimental results.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 2","pages":"1543-1561"},"PeriodicalIF":2.8,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143380977","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}

{"title":"Optimization of Conductive Partitions on the Mixed Convection in a Vented Cavity","authors":"Nihal Uğurlubilek,&nbsp;Zerrin Sert,&nbsp;Fatih Selimefendigil,&nbsp;Hakan F. Öztop","doi":"10.1002/htj.23200","DOIUrl":"https://doi.org/10.1002/htj.23200","url":null,"abstract":"<div>\u0000 \u0000 <p>Numerical estimation for the impacts of the conductive partitions having different positions on the mixed laminar convection of air in a 2D vented enclosure was examined. The variable parameters are accepted as Reynolds number (<i>Re</i> = 10–1000), Richardson number (<i>Ri</i> = 0–5), and size of the partition (0.25<i>H</i>, 0.5<i>H</i>, and 0.75<i>H</i>). Twelve cases having several partition arrangements were analyzed. It was observed that excellent convection control can be obtained by using conductive partitions depending upon the <i>Re</i> and <i>Ri</i> combinations. Generally, at small <i>Re</i>, the mean <i>Nu</i> was not affected by the variation of geometry and <i>Ri</i> at small <i>Re</i>. The highest <i>Nu</i> is achieved in Case 12, a cavity with two partitions having a length of 0.75. At <i>Re</i> = 1000, the rate of increase in <i>Nu</i> at <i>Ri</i> = 0, 1, and 5 are obtained at 2.085, 1.868, and 1.43 according to the bare cavity, respectively. In addition, the effect of the solid–fluid thermal conductivity ratio (<i>K</i> = 0.002, 0.2, 1, 5, and 40) on heat transfer was investigated for Case 12. Empirical power-law Nusselt number correlation was derived for a 2D vented cavity with/without conductive partitions. In conclusion, the maximum heat transfer enhancement rate is obtained in the vented cavity with two length partitions of 0.75. At <i>Re</i> = 1000, the increases in heat transfer rate (<i>Nu</i>/<i>Nu</i>₀) for <i>Ri</i> = 0, 1, and 5 are 2.085, 1.87, and 1.43 times higher, respectively, compared with the bare cavity. In terms of effectiveness, Case 12 is the optimum case after Case 0.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 2","pages":"1530-1542"},"PeriodicalIF":2.8,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143380976","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}

{"title":"Performance of North Wall Modified Passive and Active Greenhouse Groundnuts Dryers","authors":"Shimpy,&nbsp;Mahesh Kumar,&nbsp;Vishal Sahu,&nbsp; Mahesh,&nbsp;Shravan Yadav,&nbsp;Aman Saini","doi":"10.1002/htj.23237","DOIUrl":"https://doi.org/10.1002/htj.23237","url":null,"abstract":"<div>\u0000 \u0000 <p>An even-span greenhouse groundnuts dryer having a reflective north wall has been developed and tested under passive and active modes. The effects of varying sample mass (580, 880, and 1180 g) on the thermal and enviro-economic performance indicators of the dryer have been investigated. The Nusselt number expression, embodied energy (EE), and capital cost (<i>C</i>_c) were used for thermal, environmental, and economic assessment of the dryer. The drying behavior of the groundnuts samples has also been estimated using the moisture ratio in drying models. Thermal indicators were observed to increase with increased sample mass and were found higher under active mode. The values of EE and <i>C</i>_c of the dryer under passive and active modes were 145.24 and 158.42 kWh, and INR 1257.11 and INR 2157.11, respectively. Enviro-economic indicators were also observed to improve with increased sample mass and were comparable for both the passive and active modes. The moisture ratio for all the samples shows an excellent fit with the Midilli–Kucuk model. An average Midilli–Kucuk model has been recommended to predict the drying behavior of groundnuts in the developed greenhouse dryer.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 2","pages":"1517-1529"},"PeriodicalIF":2.8,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143380942","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}

{"title":"Thermally Intense Cilia Generated Motion of Two-Phase Biological Fluid in a Vertical Tube Under Wall Properties","authors":"Mubbashar Nazeer,&nbsp;Muna Al-Razgan,&nbsp;Yasser A. Ali,&nbsp;Talib K. Ibrahim,&nbsp;Nargiza Kamolova,&nbsp;Manish Gupta","doi":"10.1002/htj.23225","DOIUrl":"https://doi.org/10.1002/htj.23225","url":null,"abstract":"<div>\u0000 \u0000 <p>The exact solution is obtained for the unsteady fluid–particle suspension model of Rabinowitsch fluid through a vertical tube having ciliated walls. The flow inside the tube is produced by the metachronal waves of cilia. The lubricant approach is used to produce the solution of fluid phase velocity, particle phase velocity, stream function, and temperature. The pressure rise is calculated through a numerical analytical technique. The graphs are constructed to explore the characteristics of the velocity of both phases, thermal analysis, trapping phenomena, pressure gradient, and pressure rise. It is known that the slip parameter diminishes the velocity of both phases. The thermal slip parameter and density number upsurge the thermal profile. The particle phase velocity is less than the fluid phase. The present analysis can be useful in biomedical engineering to construct the heart and lung machines that are used to pump blood in arteries.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 2","pages":"1506-1516"},"PeriodicalIF":2.8,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143381063","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}

{"title":"Thermo-Enviro-Economic Study of Solar Concentrated Hexagonal Covered Tubular Still Using Interrupted and Tilted Receiver","authors":"Karima E. Amori,&nbsp;Tabark A. Hussien","doi":"10.1002/htj.23231","DOIUrl":"https://doi.org/10.1002/htj.23231","url":null,"abstract":"<div>\u0000 \u0000 <p>Solar energy is still commonly used to produce clean drinking water due to its simple construction, low maintenance, and ecofriendliness. This work aims to experimentally investigate the yield upgrade and the thermal performance of a novel concentrated single-axis tracking trough tubular solar still (TSS). This tubular still is identified by three baffles that generate four interrupted sections in the U-receiver, which is inserted with copper mesh and fitted in a hexagonal-shaped glass cover. Two identical TSS models were side-by-side outdoor tested in Baghdad-Iraq 33.3° N and 43.3° E from January to March 2024. The first is inserted with black copper mesh (Model I), and the other has no insertion (Model ll). The effect of the inserted copper mesh (60, 120, and 180 g) and the receivers' tilt angle (5°, 10°, and 15°) on the still performance are involved. The still thermal performance is analyzed per heat transfer coefficients, energy, and exergy efficiencies. The results revealed that the accumulated daily yield is enhanced for Model I by 78.9%–194.8% while the thermal efficiency is enhanced by 68.3%–206.4% when it is tilted at 15° with the insertion of 60–180 g copper mesh, respectively, compared with Model II. It is concluded that an effective improvement in the solar still yield is obtained by using copper mesh.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 2","pages":"1488-1505"},"PeriodicalIF":2.8,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143381080","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}

{"title":"Experimental Investigation of Pool Boiling Heat Transfer on Cu─Al2O3 Composite Coated Patterned Surfaces Using Refrigerant R-134a","authors":"Ajay D. Pingale,&nbsp;Govind Waghmare,&nbsp;Anil S. Katarkar,&nbsp;Sagar Wankhede,&nbsp;Swapan Bhaumik,&nbsp;Sachin Belgamwar","doi":"10.1002/htj.23235","DOIUrl":"https://doi.org/10.1002/htj.23235","url":null,"abstract":"<div>\u0000 \u0000 <p>The present study investigates pool boiling heat transfer (PBHT) of R-134a on Cu─Al₂O₃ composite-coated patterned surfaces (CPS_I, CPS_II, CPS_III, and CPS_IV). Using a wire EDM method, four different types of copper patterned surfaces (PS_I, PS_II, PS_III, and PS_IV) were manufactured. Comparing the heat transfer coefficients (HTCs) of the Cu─Al₂O₃ composite-coated patterned surfaces to the uncoated Cu surfaces, a notable enhancement was observed. The maximum HTC improvements of 162%, 178%, 189%, and 211% were observed for CPS_I, CPS_II, CPS_III, and CPS_IV, respectively, when compared with bare Cu surfaces. These results demonstrate the effectiveness of these treatments in enhancing heat transfer compared to bare copper surfaces. The enhancement in PBHT is mainly due to the integration of porous Cu─Al₂O₃ composite coating with patterned surfaces which resulted in a larger heat transfer area, improved capillary action, and a substantial increase in active nucleation sites.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 2","pages":"1476-1487"},"PeriodicalIF":2.8,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143380924","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}

{"title":"Thermo-Solutal Nonlinear Convection in a Nanofluid Flow Past a Porous Plate in the Presence of Heat Generation/Absorption","authors":"Sudip Dey,&nbsp;Swati Mukhopadhyay,&nbsp;Kuppalapalle Vajravelu","doi":"10.1002/htj.23221","DOIUrl":"https://doi.org/10.1002/htj.23221","url":null,"abstract":"<div>\u0000 \u0000 <p>The aim of the present study is to analyze the effects of thermo-solutal nonlinear convection in a nanofluid flow past a vertical permeable plate in the presence of heat generation/absorption and a first-order chemical reaction. The effects of Brownian motion and thermophoresis have been included in this study. By using similarity transformations, the ordinary differential equations (ODEs) are obtained from the governing partial differential equations (PDEs). Then by using a Runge-Kutta (R-K) method coupled with a shooting technique, numerical solutions are obtained. The effects of the relevant physical parameters on the velocity, the temperature, and the nanoparticle volume fraction are analyzed. When the magnitude of the thermal buoyancy parameter and solutal buoyancy parameter increase, the fluid velocity initially rises rapidly and then diminishes. But the temperature and concentration fields reduce. Near the plate, the fluid velocity is found to enhance with increasing values of the thermo-quadratic convection parameter as well as with the rising values of the solutal-quadratic convection parameter. However, both the temperature and the nanoparticle volume fraction reduce. The results of this study are interesting and motivating for further investigations on the problem for different situations and with different geometries.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 2","pages":"1394-1419"},"PeriodicalIF":2.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143380719","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}

{"title":"Impacts of Double Rotating Cylinders on the Forced Convection of Nanoencapsulated Phase Change Material","authors":"Aissa Abderrahmane,&nbsp;Houssem Laidoudi,&nbsp;Alhadj Hisseine Issaka Ali,&nbsp;Abdeldjalil Belazreg,&nbsp;Obai Younis,&nbsp;Riadh Marzouki","doi":"10.1002/htj.23234","DOIUrl":"https://doi.org/10.1002/htj.23234","url":null,"abstract":"<div>\u0000 \u0000 <p>Many engineering and industrial applications rely on heat transfer (HT) as a basic and central process. Therefore, engineers and researchers place significant emphasis on optimizing HT rates. Here, we numerically attempt to maximize the heat transmission rate of mixed convection of nanoencapsulated phase change material in a square compartment. The compartment is differentially heated and incorporates two cold rotating cylinders. The Galerkin finite element approach is utilized for addressing the system governing equations. A range of various factors affecting the thermal activity in the compartment were considered. These factors include the speed of spinning cylinders (<i>Re</i> = 0–1000), the porousness of the compartment (<i>Da</i> = 10⁻⁵–10⁻²), the magnetic field intensity (<i>Ha</i> = 0–100), and the concentration of nanoadditives (<i>ϕ</i> = 0%–8%). The obtained numerical findings demonstrated that the thermal activity inside the compartment is positively correlated to the speed of the spinning cylinders, the concentration of nanoadditives, and the porousness of the compartment. In contrast, increasing the intensity of the magnetic field obstructs the heat transmission. It was noted that at the highest <i>Re</i> number, the average Nusselt number augmented by 257% and 13.6% when increasing <i>Da</i> and <i>ϕ</i>, respectively.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 2","pages":"1448-1461"},"PeriodicalIF":2.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143380718","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}