International Journal of Heat and Mass Transfer最新文献

{"title":"Molecular dynamics study on thermal properties of nanofluids enhanced by interfacial molecular orientation","authors":"Fuquan Luo,&nbsp;Yunxie Huang,&nbsp;Runkeng Liu,&nbsp;Huiying Wu,&nbsp;Zhenyu Liu","doi":"10.1016/j.ijheatmasstransfer.2025.126791","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126791","url":null,"abstract":"<div><div>Nanofluids have a wide range of applications due to its excellent thermal properties (density, thermal conductivity and heat capacity), however, the mechanisms of thermal properties enhancement for nanofluids are still debatable. In this work, the study is focused on the effects of temperature, particle concentration and surface property (hydroxylated silica or hydrogenated silica) on the thermal properties of silica/1,8-octanediol (ODL) nanofluid using the molecular dynamics (MD) simulations. It reveals that the different molecular orientation of interfacial layers formed by 1,8-ODL on the silica surface cause the differences in its thermal properties: the nanofluid with hydroxylated silica possesses a higher density and a higher thermal conductivity, while the nanofluid with hydrogenated silica possesses a higher heat capacity. Moreover, the effects of temperature and particle concentration are also investigated in this study. As the temperature increases, the thermal conductivity enhancement changes nonmonotonically and presents a maximum, which results from the combination of the limited diffusion of 1,8-ODL molecules and the adsorption-desorption of molecules in the interfacial layer. The heat capacity enhancement of nanofluids increases with temperature can be attributed to the elevated interfacial thermal resistance between 1,8-ODL and silica. With a low silica concentration, the heat capacity of nanofluids can exceed that of pure 1,8-ODL due to the existence of interfacial layer. The findings in this work emphasize the important role of interfacial layer and molecular diffusion characteristics in enhancing the thermal properties of nanofluids.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126791"},"PeriodicalIF":5.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From concept to optimization: Advancing passive microfluidic fuel cells through electrode-rib-channel innovations","authors":"Ning Yang ,&nbsp;Libo Yu ,&nbsp;Fan Ren ,&nbsp;Bowen Wang ,&nbsp;Jin Xuan ,&nbsp;Gang Wang ,&nbsp;Lei Xing","doi":"10.1016/j.ijheatmasstransfer.2025.126808","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126808","url":null,"abstract":"<div><div>Passive microfluidic fuel cells, operated with methanol and air, are novel energy conversion devices, with low pollution, high portability, and relatively low cost, to debate the increasing energy demand and environmental concerns. During operation, the cell's structure plays a crucial role in determining the ohmic and concentration losses, which are closely related with the cell performance. In this study, a numerical model was developed to investigate the performance of a passive microfluidic fuel cell, focusing on variations in three structural components: electrodes, ribs, and flow channels. Our findings demonstrated that optimal designs in each category notably enhanced the cell performance. Specifically, compared to the base case without modification, using 6 trapezoidal electrodes increased the current and power densities by 20.62 mA cm⁻² and 1.89 mW cm⁻², respectively. Additionally, the employment of 3 triangular ribs enhanced the densities by 2.5 mA cm⁻² and 0.35 mW cm⁻², respectively. Furthermore, optimizing wave-shaped channels, with an amplitude of 0.5, a period of 3, and a phase of 0, resulted in increases of 3.55 mA cm⁻² and 0.4 mW cm⁻² in current and power densities, respectively. Finally, the optimization of three distinct structural categories was integrated and conducted using response surface methodology (RSM). This comprehensive optimization significantly reduced concentration and ohmic losses by decreasing ion transport resistance, thereby enhancing the overall cell performance. Under the optimal structural parameters, the microfluidic fuel cell achieved current and power densities of 52.44 mA cm⁻² and 6.21 mW cm⁻², respectively, which represent increases of 15.56 % and 12.12 % over those achieved with single-category optimization.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126808"},"PeriodicalIF":5.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transfer machine learning framework for efficient full-field temperature response reconstruction of thermal protection structures with limited measurement data","authors":"Yuluo Chen ,&nbsp;Qiang Chen ,&nbsp;Han Ma ,&nbsp;Shuailong Chen ,&nbsp;Qingguo Fei","doi":"10.1016/j.ijheatmasstransfer.2025.126785","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126785","url":null,"abstract":"<div><div>Thermal protection structures are key components of reusable launch vehicles. As an important basis for monitoring the health status of the vehicle, it is necessary to timely and accurately predict the full-field temperature response of the thermal protection structure. In this work, a novel model is proposed for solving this problem based on physical information neural network (PINN) and transfer learning techniques, in which both the direct and inverse heat conduction problems are involved. A thermal protection structure (TPS) is taken as the research object. The corresponding simulation model is obtained based on the experimental model, which is used to train the PINN pre-model and to verify the validity and accuracy of the pre-model. Combining pre-model and limited experimental data, three different fine-tuning strategies are utilized for transfer learning. Furthermore, the PINN model obtained based on the optimal fine-tuning strategy is chosen to complete the temperature field reconstruction and thermophysical parameter recognition. Results demonstrate that the proposed method not only solves the complex problem of heat transfer across material layers but also performs well in the face of complex heat flow conditions. The experimental model obtained under the fine-tuning strategy of freezing the first two fully connected layers not only performs better in terms of accuracy and efficiency but also has the best stability during training. The training efficiency of the model is improved by more than 7 times through transfer learning. This suggests the desirability of combining transfer learning and PINN to construct experimental models dealing with direct and inverse heat conduction problems.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126785"},"PeriodicalIF":5.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An innovative inverse model for predicting the minimum protective bank inside a cylindrical electric arc furnace","authors":"Ahmed El-Hassnaoui,&nbsp;Marcel Lacroix","doi":"10.1016/j.ijheatmasstransfer.2025.126801","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126801","url":null,"abstract":"<div><div>An innovative fast inverse heat transfer method for predicting the protective phase-change banks inside a cylindrical electric arc smelter is presented. The proposed model takes into account the phase change processes and the thermal effect of the chemical reactions for the smelting of the ore. The Particle Swarm Optimization algorithm is combined with the Levenberg-Marquardt method in order to determine the minimum thickness of the protective bank from non-invasive temperature measurements taken outside the refractory brick walls of the furnace. The required number of temperature sensors and their location is determined using the Principal Component Analysis. Results show that the proposed overall inverse method is computationally faster than other existing inverse methods and, as a result, it may be incorporated to existing on-line control systems of industrial smelters.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126801"},"PeriodicalIF":5.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conjugate heat transfer characteristics of crushed coal rock mass under axial compression: Coupling numerical analysis based on CT reconstruction and FEM","authors":"Yanchi Liu ,&nbsp;Baiquan Lin ,&nbsp;Ting Liu ,&nbsp;Zhiyong Hao","doi":"10.1016/j.ijheatmasstransfer.2025.126788","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126788","url":null,"abstract":"<div><div>This study focuses on the heat transfer characteristics of crushed coal under axial compression in deep abandoned mines during geothermal extraction. By combining visualized experiments with CT image reconstruction, the study overcame the limitation in the simulation scale, increase the size of finite element model by tens of times. The transient conjugate heat transfer of multi-phase fluid flow process in real axial pressure crushed coal at macro scale is realized. The key findings are as follows: With regard to the thermal conductivity characteristics, the effective thermal conductivities of models filled with different fluids rise linearly with the increase in thermal conductivity of the matrix. As for conjugate heat transfer characteristics, dominant heat transfer paths significantly impact conjugate heat transfer during the non-steady-state phase. An increase in boundary velocity enhances heat extraction efficiency. However, when the boundary velocity increases to 0.001 m/s, the thermal breakthrough time decreases by 66.8 %. Additionally, an increase in the initial temperature difference enhances the heat extraction rate and thermal recovery rate. When gaseous CO₂ is used as the fluid, the temperature and conductive heat flux differences in the heat transfer model are mainly manifested as axial stratification. This research provides an important theoretical support for the development of digital core technology for heat transfer research.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126788"},"PeriodicalIF":5.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of excavation and soil recovery on soil temperature and ground infrared radiation containing a metal-bearing block","authors":"Shengkang Hu ,&nbsp;Yuge Han ,&nbsp;Qunqing Lin ,&nbsp;Dengfeng Ren","doi":"10.1016/j.ijheatmasstransfer.2025.126802","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126802","url":null,"abstract":"<div><div>The effect of excavation and soil recovery on the soil temperature field and surface infrared properties is a critical factor in shallow subsurface target detection, yet it has not been sufficiently addressed in existing research. This study employs a combined discrete element method and MIE scattering model to simulate the changes in soil surface morphology and physical properties after the shallow burial of metal blocks in sandy, loamy, and clay soils. By integrating soil heat and moisture transfer with an infrared radiation model, we simulate the resulting temperature field and infrared radiation characteristics of the surface after excavation. The results indicate that the granularity of sandy soils and the high cohesion of clay soils lead to relatively minor changes in surface morphology and physical parameters in comparison to loamy soils. Infrared imaging analysis reveals that buried materials are most easily detected in loamy and clayey soils, while detection is more challenging in sandy soils. Furthermore, the comparison of temperature differences between the surface center and surrounding environment demonstrates that the characteristics of buried objects in loamy and clay soils are most pronounced at 12:00 and 24:00, enhancing the feasibility of underground target detection at these times. The study also found that different excavation speeds had a minimal impact on soil parameters at the surface. Faster excavation speeds increase shear stresses at the subsurface interface, thereby enhancing the density of the subsurface layer. Additionally, stronger solar radiation was found to improve the detection of buried objects, reducing the difficulty of underground target identification. The methodology proposed in this paper provides a more realistic approach to underground target detection by accounting for the dynamic changes in soil properties during excavation and recovery processes.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126802"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal boundary layer modelling for bubbles at saturation: A posteriori analysis","authors":"Mathis Grosso ,&nbsp;Guillaume Bois ,&nbsp;Adrien Toutant","doi":"10.1016/j.ijheatmasstransfer.2025.126744","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126744","url":null,"abstract":"<div><div>This study investigates different temperature and flux coupling strategies in Direct Numerical Simulations (DNS) of bubbles at saturation, employing local one-dimensional thermal boundary layer sub-resolutions. Specifically, a laminar radial sub-resolution (LRS) near the interface is employed to address challenges in capturing sharp temperature variations, which is crucial for liquid–vapour heat transfer correlations. State-of-the-art techniques use analytical profiles to capture very thin boundary layers around single-rising objects for very high Prandtl or Schmidt numbers. The original approach proposed in Grosso et al. (2024) relies on a more general embedded sub-resolution still applicable at low Prandtl numbers and coarse grids. To accurately integrate the sub-layer variations into the CFD grid, the literature recommends using the sub-grid profiles to evaluate the Eulerian face fluxes instead of correcting cell temperature. From experience, it avoids excessive flux leakage from the sub-layer region at high Prandtl numbers. The present article investigates these coupling methods while proposing adaptations for thick boundary layers and very coarse grids in the context of LRS. Two test cases, pure diffusion acting around a sphere and a single rising bubble configuration, are explored, measuring heat flux at the interface and its transmission to the fluid domain serving as figures of merit for each coupling method. In low Prandtl bubbly flows (<span><math><mrow><mi>P</mi><msub><mrow><mi>r</mi></mrow><mrow><mi>l</mi></mrow></msub><mo>≤</mo><mn>5</mn></mrow></math></span>), and on coarse and affordable grids (<span><math><mrow><mo>&lt;</mo><mn>20</mn></mrow></math></span> cells per bubble diameter), temperature coupling is found to be more stable though not conservative compared to flux coupling approaches. On the other hand, classical flux coupling strategies can exhibit artefacts and introduce potential instabilities with LRS. To overcome such problems, an improved local flux balance approach is proposed, demonstrating both robustness and efficiency in predicting and transmitting interfacial flux across the tested thermal layers’ thickness ranges.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126744"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat transfer of impinging sweeping jets: Influence of nozzle-to-target spacing and feedback channel minimum passage width","authors":"Cristina D’Angelo,&nbsp;Gerardo Paolillo,&nbsp;Carlo Salvatore Greco,&nbsp;Gennaro Cardone,&nbsp;Tommaso Astarita","doi":"10.1016/j.ijheatmasstransfer.2025.126773","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126773","url":null,"abstract":"<div><div>Infrared Thermography and the heated thin foil heat flux sensor are employed to experimentally investigate the heat transfer characteristics of sweeping jets impinging on a flat surface. Multiple nozzle-to-target spacings <span><math><mi>H</mi></math></span> (<span><math><mrow><mi>H</mi><mo>/</mo><mi>w</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>5</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>1</mn><mo>.</mo><mn>5</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>4</mn><mo>,</mo><mn>6</mn><mo>,</mo><mn>8</mn></mrow></math></span> and 10, where <span><math><mi>w</mi></math></span> represents the width of the square exit nozzle throat) and feedback channel minimum passage widths <span><math><mi>g</mi></math></span> (<span><math><mrow><mi>g</mi><mo>/</mo><mi>w</mi><mo>=</mo><mn>1</mn><mo>,</mo><mn>0</mn><mo>.</mo><mn>83</mn><mo>,</mo><mn>0</mn><mo>.</mo><mn>67</mn><mo>,</mo><mn>0</mn><mo>.</mo><mn>50</mn><mo>,</mo><mn>0</mn><mo>.</mo><mn>33</mn><mo>,</mo><mn>0</mn><mo>.</mo><mn>17</mn></mrow></math></span> and 0) are analyzed to evaluate the effects of these two parameters on the convective heat transfer of the investigated jets. The Reynolds number is set to <span><math><mrow><mn>1</mn><mo>.</mo><mn>47</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span> for all the experiments performed. To assess the heat transfer behavior of the studied sweeping jet device, both time-averaged and phase-averaged analyses are conducted. This study demonstrates that the convective heat transfer of the impinging sweeping jet affects a broader area of the foil as the nozzle-to-target spacing increases, whereas the opposite effect is observed when reducing the minimum passage width of the feedback channels. Furthermore, the time-averaged analyses reveal that for <span><math><mrow><mn>0</mn><mo>.</mo><mn>5</mn><mo>≤</mo><mi>H</mi><mo>/</mo><mi>w</mi><mo>≤</mo><mn>1</mn><mo>.</mo><mn>5</mn></mrow></math></span>, compared to the corresponding steady jet, sweeping jets enhance the convective heat transfer close to the impingement center of the target surface; instead, for <span><math><mrow><mi>H</mi><mo>/</mo><mi>w</mi><mo>&gt;</mo><mn>2</mn></mrow></math></span> the steady jet exhibits superior heat transfer performance near the stagnation region, while the sweeping jets generate a more uniformly distributed region of maximum convective heat transfer. Additionally, the analysis of the phase-averaged Nusselt number distributions across the target surface reveals that the maximum convective heat transfer region is situated on its uphill side, close to the stagnation point, resembling the behavior of inclined impinging jets.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126773"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling electron beam melting through electron trajectory control in electromagnetic fields for homogeneous titanium ingot manufacturing","authors":"HyunChul Kim ,&nbsp;Soosung Kim ,&nbsp;YongKwan Lee ,&nbsp;Jae-Hong Shin ,&nbsp;Donghyun Kim ,&nbsp;SoongJu Oh ,&nbsp;Kyoung-Tae Park","doi":"10.1016/j.ijheatmasstransfer.2025.126799","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126799","url":null,"abstract":"<div><div>Electron beam melting (EBM), which is used to prepare ultra-high-purity refractory and rare metals with high melting points, is associated with an extremely high energy density of tens of megawatts per unit area. The shape and momentum of the electron beam can be adjusted by controlling the electromagnetic field within the electron-beam device to generate this high energy density. However, the energy density in EBM may decrease depending on the beam geometry and magnetic field strength of the focusing coil. To achieve high energy efficiency, the flux density generated by the focusing coil of the electron beam gun should be controlled such that the focusing point of the electron beam is on the surface of the molten material. In this study, the electron beam trajectory in the EBM process was altered by controlling the momentum of the electrons generated by the electric field and the shape of the electron beam produced under the magnetic field generated by the solenoid coil. Finite element analysis was performed to establish the process conditions required to form a beam with high energy efficiency and to minimize the electron bundle loss due to collisions with the inner wall. Our findings can be applied to the refinement of rare metals through high-efficiency energy-beam generation using electron-beam devices with various specifications. The necessary conditions for the electron beam to attain a Gaussian distribution are also outlined. To validate the simulation results, a real-time monitoring of a metal surface subjected to electron-beam irradiation was conducted using a thermal imaging camera. The predicted melting characteristics of titanium, based on electron beam trajectory and turbulence heat transfer models, were validated by ingot manufacturing experiments, confirming the model's applicability.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126799"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hot spot temperature optimization of turbulent heat convection systems: Application to battery thermal management systems","authors":"Jiajun Zhang ,&nbsp;Mengxuan Song ,&nbsp;Xiaoling Wu ,&nbsp;Zhenli Zhang ,&nbsp;Kai Chen","doi":"10.1016/j.ijheatmasstransfer.2025.126779","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126779","url":null,"abstract":"<div><div>Reduction of hot spot temperature is extremely important for power devices. Optimization equations using variational method are effective approaches to analyze convective heat transfer process. However, it is still lack of turbulent convective heat transfer optimization equations for minimization of hot spot temperature. In this work, the turbulent convective heat transfer optimization is investigated using variational method, with the aim of minimizing the hot spot temperature at customized regions. A continuous function that characterizes hot spot temperature is adopted as the objective function. The optimization equations with fixed total viscous dissipation are derived using the variational method, by solving which, the optimal flow field is obtained to achieve the minimum hot spot temperature. Subsequently, the developed optimization equations are applied to optimize the flow fields of the battery thermal management systems with different flow patterns. Numerical results demonstrate that the optimal flow fields from the developed optimization equations achieve lower hot spot temperature and temperature difference inside the battery pack, as compared to those obtained using extremum entransy dissipation in previous studies. Combined with the flow resistance network model, an iterative optimization strategy based on the optimal flow fields is further developed for structural design of the systems. The optimized systems exhibit superior performance in terms of hot spot temperature and temperature difference compared to the original systems before optimization. Finally, the effectiveness of this optimization strategy is validated by experiments. Compared with the systems before optimization, the experimental system with optimized parallel channel widths reduces the hot spot temperature and temperature difference by 6.3 K and 74 % respectively, and the system with optimized inlet defector reduces the hot spot temperature and temperature difference by 5.4 K and 67 % respectively. The optimal flow fields obtained from the developed optimization equations provide valuable insights for designing turbulent convective heat transfer systems which aim at reducing hot spot temperature, and the proposed strategy based on the optimal flow field shows great potential for efficient structural design of battery thermal management systems.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126779"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}