International Journal of Heat and Fluid Flow最新文献

{"title":"Experimental study on mixed convection of liquid metal GaInSn","authors":"Jian-Dong Zhou ,&nbsp;Yu-Hao Tang ,&nbsp;Jia-Jun Wu ,&nbsp;Juan-Cheng Yang ,&nbsp;Ming-Jiu Ni","doi":"10.1016/j.ijheatfluidflow.2025.109995","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109995","url":null,"abstract":"<div><div>Mixed convection is of great importance for the thermal–hydraulic characteristics of nuclear fast reactors and nuclear fusion blankets. In the present study, the liquid metal mixed convection is experimentally studied by adopting GaInSn, which remains in a liquid state at room temperature. The test section is a duct with a cross-area of 50 mm × 50 mm and a length of 3 m made of stainless steel. By installing the thermocouples, flow meter, and differential pressure transducers on the experimental system, the corresponding flow and heat transfer characteristics can be identified with considering the influence of flow rate and heat flux density. The present results show that, compared to forced convection, the Nusselt number (<em>Nu</em>) of mixed convection decreased first and then increased with the increase of Reynolds number (<em>Re</em>). There exists a critical <em>Re</em>_c when <em>Nu</em> reaches a minimum value, and <em>Re</em>_c increases with the increase of the Grashof number (<em>Gr</em>). It is a consequence of flow layering, plume sweeping, and bulk heat entrapment, due to the competition between buoyancy and shear forces, which can be described by the Richardson number (<em>Ri</em>). The change tendency of <em>Nu</em> as a function of <em>Ri</em> indicates that the threshold value of <em>Ri</em>_c is around 1. An empirical correlation is obtained to predict <em>Nu</em> for GaInSn mixed convection when <em>Pe</em> &lt; 1000. The variation of the local <em>Nu</em> in flow direction indicates the existence of the onset of mixed convection in the flow direction, which is further confirmed by the power spectral density.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109995"},"PeriodicalIF":2.6,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144724777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel three-dimensional topology-optimized cold plate design for lithium-ion battery thermal management based on Murray’s law","authors":"Jiao Wang ,&nbsp;Shengke Tang ,&nbsp;Zilong Song ,&nbsp;Xiaojun Fan ,&nbsp;Chuang Gao","doi":"10.1016/j.ijheatfluidflow.2025.109997","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109997","url":null,"abstract":"<div><div>The flow channel design of liquid cold plates is a critical aspect of battery thermal management systems. This study aims to develop a novel 3D topology-optimized cold plate design method based on Murray’s law to enhance the thermal management performance of lithium-ion batteries. To address the limitations of the conventional approach that directly stretches 2D topology optimization results to form 3D cold plates, a new design strategy involving secondary optimization based on Murray’s law is proposed to generate scientifically improved 3D cold plate structures. Numerical simulations are employed to systematically investigate the effects of cold plate type, inlet mass flow rate, coolant and ambient temperatures, and channel depth on the performance of the cold plates. The optimal channel depth for each hydraulic diameter is identified. The results indicate that, under identical conditions, the optimized cold plate (OP) achieves a heat transfer coefficient improvement of up to 122.12 % compared to the conventional stretched plate (SP), significantly enhancing battery temperature control. Moreover, the Performance Evaluation Criterion (PEC) of the OP increases by up to 55.36 % relative to the SP, and can be further improved by 34.84 % through channel depth optimization. The study also reveals that for each inlet hydraulic diameter, the optimal channel depth is 0.5 mm greater than that of the corresponding SP. This research provides a new optimization approach and methodology for the efficient design of cold plates in lithium-ion battery thermal management systems.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109997"},"PeriodicalIF":2.6,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Visualization of transient boundary heat transfer of supercritical CO2 through-flow in mini-channel under top heating","authors":"Gang Zeng ,&nbsp;Lin Chen ,&nbsp;Haizhuan Yuan ,&nbsp;Yanping Huang","doi":"10.1016/j.ijheatfluidflow.2025.109994","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109994","url":null,"abstract":"<div><div>The top-heated heat transfer dynamics of supercritical CO₂ (sCO₂) are critical for applications like power cycles, nuclear reactor cooling, duct heat exchangers, solar energy, and spacecraft thermal management. This study focuses on the experimental measurement of the transient boundary heat transfer behavior of sCO₂ inside a mini-channel under local heat flux from above. The flow starts from the pre-existing turbulent dynamics, followed by local heating from upper walls. A pixelated phase-shifting interferometer was employed to observed the test object, enabling quantitative analysis of the thermal boundary layer influenced by the combination of buoyancy effects and local top heating. The results reveal that: (1) the density stratification (∼0.7 kg/m³), predominantly formed in the upper region as the low-density fluid heatedly flows upward, significantly suppresses the generation of convention; (2) increased heat flux enhances the density shifts and buoyancy, accelerating lighter/hotter fluid perturbations and broadening the spectrum of secondary flows across the entire observed window; (3) relatively larger density shifts but smaller temperature gradients are observed under supercritical conditions (∼0.9 kg/m³, ∼0.006 K) compared to subcritical ones (∼0.25 kg/m³, ∼1.1 K), yielding more pronounces secondary flows and thermal stratification along the midline of the vertical axis.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109994"},"PeriodicalIF":2.6,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144711717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of entrainment and mixing in a supersonic air ejector using Large-Eddy Simulation","authors":"R. Debroeyer ,&nbsp;T. Toulorge ,&nbsp;M. Rasquin ,&nbsp;G. Winckelmans ,&nbsp;Y. Bartosiewicz","doi":"10.1016/j.ijheatfluidflow.2025.109978","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109978","url":null,"abstract":"<div><div>The interest towards supersonic ejectors as replacement for compressors in various industrial applications has grown over the last decade. In contrast with the simplicity of their working principle, the turbulent phenomena responsible for the entrainment and mixing are still not fully understood nor well captured by numerical simulations. Indeed, mostly Reynolds-Averaged Navier–Stokes (RANS) simulations have been performed up to now, where the unsteady phenomena responsible for the entrainment are solely modeled using an effective turbulent viscosity, and that also needs calibration. This work aims at providing the tools to improve the understanding and design of those devices by analyzing the instantaneous and averaged fields from a Large-Eddy Simulation (LES) of a supersonic air ejector. First, the structure of the mixing layers is analyzed, showing a very early transition to turbulence in the shear layers and the necessity to properly capture the associated fluctuations. The impact of turbulence injection in the primary flow is also discussed. Then, the post-processing tools, using total exergy fluxes, are presented. The exergy fluxes between the streams in the mixing duct are computed, and are compared to their incomplete counterpart obtained using RANS simulation results. The observed discrepancies are shown to be due to the large differences in the turbulent shear stress and turbulent heat flux through the shear layer between the RANS and LES results. A new criterion to measure the completion of the mixing between the flows is introduced thanks to a novel decomposition of the total exergy flux. Finally, the complete mixing of both streams, as newly defined, is shown not to be a sufficient condition to find the optimum performance of the ejector, e.g. a maximum compression at the maximum flow rate of the secondary stream. This optimum is found to be much more dependent on the balance between shear stress between streams and wall-friction.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109978"},"PeriodicalIF":2.6,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144711738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 impact of pressure gradient history on flow structures in High Reynolds number rough wall turbulence","authors":"T. Preskett,&nbsp;B. Ganapathisubramani","doi":"10.1016/j.ijheatfluidflow.2025.109942","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109942","url":null,"abstract":"<div><div>High Reynolds number experiments are conducted over a rough wall with strong non-equilibrium pressure gradients. The boundary layer is exposed to different pressure gradient histories via an aerofoil mounted above the boundary layer. Particle image velocity (PIV) allows for the flow development from one chord upstream of the leading edge to one chord downstream of the trailing edge to be captured (3.75 m or <span><math><mrow><mo>≈</mo><mn>22</mn><msub><mrow><mi>δ</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow></math></span>). The freestream speed upstream of the aerofoil is set to 20 m/s, and the resulting <span><math><mrow><mi>R</mi><msub><mrow><mi>e</mi></mrow><mrow><mi>τ</mi></mrow></msub></mrow></math></span> varies from 12900 to 18500. The integral pressure gradient history parameter is seen to have a second-order relationship with the wake strength, <span><math><mi>Π</mi></math></span>. Furthermore, the extent to which the upstream history has to be accounted for is considered. The structures within the flow are examined first through the mean turbulence intensity profiles as well as quadrant analysis. These results show that the effect of flow events on adverse and favourable pressure gradients varies depending on the position within the boundary layer. Some success is achieved in matching the turbulence profiles and flow structure length scales through the integral of the pressure gradient history. The agreement is improved for cases where the local pressure gradient history parameter is also matched.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109942"},"PeriodicalIF":2.6,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A generalisable data-augmented turbulence model with progressive and interpretable corrections for incompressible wall-bounded flows","authors":"Mario Javier Rincón ,&nbsp;Martino Reclari ,&nbsp;Xiang I.A. Yang ,&nbsp;Mahdi Abkar","doi":"10.1016/j.ijheatfluidflow.2025.109970","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109970","url":null,"abstract":"<div><div>The integration of interpretability and generalisability in data-driven turbulence modelling remains a fundamental challenge for computational fluid dynamics applications. This study yields a generalisable advancement of the <span><math><mi>k</mi></math></span>-<span><math><mi>ω</mi></math></span> Shear Stress Transport (SST) model through a progressive data-augmented framework, combining Bayesian optimisation with physics-guided corrections to improve the predictions of anisotropy-induced secondary flows and flow separation simultaneously. Two interpretable modifications are systematically embedded: (1) a non-linear Reynolds stress anisotropy correction to enhance secondary flow predictions, and (2) an activation-based separation correction in the <span><math><mi>ω</mi></math></span>-equation, regulated by an optimised power-law function to locally adjust turbulent viscosity under adverse pressure gradients. The model is trained using a multi-case computational fluid dynamics-driven <em>a posteriori</em> approach, incorporating periodic hills, duct flow, and channel flow to balance correction efficacy with baseline consistency. Validation across multiple unseen cases – spanning flat-plate boundary layers, high-Reynolds-number periodic hills, and flow over diverse obstacle configurations – demonstrates enhanced accuracy in velocity profiles, recirculation zones, streamwise vorticity, and skin friction distributions while retaining the robustness of the original <span><math><mi>k</mi></math></span>-<span><math><mi>ω</mi></math></span> SST in attached flows. Sparsity-enforced regression ensures reduced parametric complexity, preserving computational efficiency and physical transparency. Results underscore the framework’s ability to generalise across geometries and Reynolds numbers without destabilising corrections, offering a validated framework toward deployable, data-augmented turbulence models for numerical simulations.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109970"},"PeriodicalIF":2.6,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Parametric analysis of a metal foam-based PVT collector coupled with a ventilated room for building heating","authors":"Hani Boussenah ,&nbsp;Abderrahim Bourouis ,&nbsp;Abdullah A. AlZahrani ,&nbsp;Abdeslam Omara ,&nbsp;Samir Djimli","doi":"10.1016/j.ijheatfluidflow.2025.109985","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109985","url":null,"abstract":"<div><div>This study numerically investigates the thermal and dynamic integration between a hybrid photovoltaic-thermal (PVT) solar collector and a ventilated room for efficient renewable heating. To enhance heat transfer, a metal foam layer is embedded beneath the photovoltaic cells. Two distinct domains are considered in this study: laminar flow is assumed in the PVT air channel and simulated using an in-house FORTRAN code based on the finite volume method, while turbulent flow is assumed in the ventilated room and simulated using ANSYS Fluent with the standard k–ε turbulence model. A comprehensive parametric analysis is conducted to evaluate the influence of key parameters, including inlet air velocity, porous medium porosity, Darcy number, and the dimensionless porous layer thickness, on the overall system performance. The results indicate that increasing the porosity from 0.2 to 0.98 reduces electrical efficiency from 12.2 % to 9 %. However, the thermal efficiency shows gains of 67 %, 52 %, 45 %, and 35 % for inlet air velocities of 0.2, 0.3, 0.4, and 0.5 m/s, respectively. At high Darcy numbers (Da ≥ 10⁻³), increasing the porous layer thickness up to 0.8 enhances the system performance, leading to improvements of 47.8 %, 22 %, and 23 % in thermal efficiency, electrical efficiency, and average room temperature, respectively.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109985"},"PeriodicalIF":2.6,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the methods of extracting attached eddies","authors":"X.X. Li ,&nbsp;L. Fang","doi":"10.1016/j.ijheatfluidflow.2025.109983","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109983","url":null,"abstract":"<div><div>The success of the attached eddy model (AEM) and the search for typical representations of attached eddies call for the development of various methods for extracting attached eddies. However, previous studies have not systematically compared these methods in terms of their statistical wall laws for different physical quantities. In particular, the wall laws for arbitrary moments of the velocity gradient and higher-order velocity derivatives in the logarithmic region, derived in our previous study, have not been checked by using these various methods. In the present study, we focus on three methods, that is, the spectral filtering based on streamwise wavelength (SF), proper orthogonal decomposition (POD), and clustering methodology (CM), and assess their ability of capturing the statistical characteristics predicted by the AEM. It is found that based on two-dimensional instantaneous flow fields, the SF method demonstrates the best performance in capturing the statistical laws of velocity gradients and Hessians, followed by CM, while POD proves inadequate for capturing the scaling laws of velocity gradients and Hessians. Moreover, a parametric analysis is carried out to discuss in detail the specific effects of various parameters in each method on the statistical moments. These results are expected to identify key parameters in these methods and contribute to their improvement, enabling better capture of the statistical laws predicted by the AEM.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109983"},"PeriodicalIF":2.6,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 influence of nozzle geometries and operating modes on the propulsive performance of continuous unsteady jet","authors":"Xiaofeng He,&nbsp;Yin Li,&nbsp;Wei Yu,&nbsp;Hewen Huang","doi":"10.1016/j.ijheatfluidflow.2025.109986","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109986","url":null,"abstract":"<div><div>In this paper, the effects of the nozzle geometry, formation time and duty cycle on the propulsive performance of continuous unsteady jets were experimentally investigated. Total of seven types of nozzles with different specific cavity shapes and nozzle lip angles were considered, which can be categorized into straight, contracting and expanding nozzles. The output thrust and input power of continuous unsteady jets in different modes of operation are obtained. Based on the experiment data, the power–thrust ratio was used to evaluate the energy conversion efficiency of continuous unsteady jets. The results indicate that the energy saving effect is positively correlated to the mean jet Reynolds number, which the continuous unsteady jet can have high efficiency in the operating mode with small formation time and duty cycle. Furthermore, it is proved that the small nozzle lip angle is conducive to the energy saving of unsteady jets. Analyzed from energy-optimal perspective, among the different nozzles, the hyperbolic nozzle has optimal propulsive performance under the formation time 3.03 and duty cycle 0.4. At this time, the power–thrust ratio is 0.018 watts per newton. The Vitosinski nozzle works under the formation time 2.82 has the widest duty cycle range for high efficiency operation.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109986"},"PeriodicalIF":2.6,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on heat transfer and flow characteristics of latent functionally thermal fluid in circular tubes with embedded fins","authors":"Chenzhen Liu ,&nbsp;Peng Zhao ,&nbsp;Peng Yang ,&nbsp;Peizhao Lyu ,&nbsp;Xinjian Liu ,&nbsp;Zhonghao Rao","doi":"10.1016/j.ijheatfluidflow.2025.109992","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109992","url":null,"abstract":"<div><div>In this paper, an experimental investigation was arranged to study the heat transfer and flow characteristics of latent functionally thermal fluid (LFTF) in circular tubes with different fins (smooth tube, straight finned tube, and cross finned tube). The water-based microencapsulated phase change materials suspension (MPCS) as LFTF was prepared. The effects of microencapsulated phase change materials (MicroEPCM) mass concentration, inlet temperature, heat flux, and circular tube structure on heat transfer and flow performance of MPCS were investigated. The results indicated that the convective heat transfer capacity of MPCS was significantly better than that of water under the same experimental conditions. The optimal inlet temperature and heat flux were 29 °C and 4301.48 W/m², respectively. Among the three types of circular tube structures, the cross-fin tube exhibited the best enhanced heat transfer capability but also resulted in the highest pressure drop loss. When the heat exchange section was a smooth circular tube, the comprehensive evaluation coefficients of 5 wt% MPCS and 10 wt% MPCS were approximately 1.3 and 1.5 times higher than that of water, respectively. This demonstrated that MicroEPCM can enhance the overall heat transfer capability. This study investigated the heat transfer and flow characteristics of LFTF in circular tubes, contributing to the expansion of its practical applications electronic device heat dissipation and battery thermal management.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109992"},"PeriodicalIF":2.6,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}