Pub Date : 2026-01-15DOI: 10.1016/j.ijheatfluidflow.2026.110264
Stephon De Souze, Victor M. Job, Mahesha Narayana
In the present study, the effects of magnetic field strength, nanoparticle magnetization, natural convection, tumour blood retention capacity and tumour rigidity on magnetic hyperthermia cancer therapy in malignant liver tissues in a solenoidal magnetic field are considered. The liver tissue region is modelled as a thermoporoelastic healthy liver tissue surrounding a cancerous region. This is achieved by using the Navier–Cauchy equations to describe the deformation of the tissues, Darcy’s law to describe the fluid flow, continuity equation to describe the conservation of mass and the energy equation to describe the temperature distribution within our system. A finite element/finite difference scheme for this system of equations is constructed and implemented via MATLAB R2024a, and the results are simulated graphically. It was found that an increase in magnetic field strength or nanoparticle magnetization significantly increases the tissue temperature and the chance of tissue death within our system. Moreover, it also significantly increases the deformation of the tissues and interstitial blood pressure. Although the blood retention and rigidity of the tumour significantly affect the local blood pressure and the deformation, they have a negligible effect of the temperature and tissue cell death. The major implication of these findings is that the effectiveness of this therapy is not significantly impacted by tumour blood retention capacity or tumour rigidity, but is greatly affected by the magnetic field strength and nanoparticle magnetization.
{"title":"In-silico study of intratumoural magnetic hyperthermia in thermoporoelastic liver tissues using Fe3O4 nanoparticles","authors":"Stephon De Souze, Victor M. Job, Mahesha Narayana","doi":"10.1016/j.ijheatfluidflow.2026.110264","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110264","url":null,"abstract":"<div><div>In the present study, the effects of magnetic field strength, nanoparticle magnetization, natural convection, tumour blood retention capacity and tumour rigidity on magnetic hyperthermia cancer therapy in malignant liver tissues in a solenoidal magnetic field are considered. The liver tissue region is modelled as a thermoporoelastic healthy liver tissue surrounding a cancerous region. This is achieved by using the Navier–Cauchy equations to describe the deformation of the tissues, Darcy’s law to describe the fluid flow, continuity equation to describe the conservation of mass and the energy equation to describe the temperature distribution within our system. A finite element/finite difference scheme for this system of equations is constructed and implemented via MATLAB R2024a, and the results are simulated graphically. It was found that an increase in magnetic field strength or nanoparticle magnetization significantly increases the tissue temperature and the chance of tissue death within our system. Moreover, it also significantly increases the deformation of the tissues and interstitial blood pressure. Although the blood retention and rigidity of the tumour significantly affect the local blood pressure and the deformation, they have a negligible effect of the temperature and tissue cell death. The major implication of these findings is that the effectiveness of this therapy is not significantly impacted by tumour blood retention capacity or tumour rigidity, but is greatly affected by the magnetic field strength and nanoparticle magnetization.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110264"},"PeriodicalIF":2.6,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974409","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}
Pub Date : 2026-01-12DOI: 10.1016/j.ijheatfluidflow.2026.110261
Zheng Zhao , Jiangyi He , Running Wang , Tingting Jing , Xing Sun , Jiaping Zhang
Struts are usually adopted in hypersonic engines for efficient fuel injection. Sufficient thermal protection is need for injection struts under extremely high temperature gas scouring environment. The objective of this study is to verify the reliability of the C/SiC-HfB2-HfC composite leading-edge strut under Ma6 engine combustor operation conditions. The heat transfer and ablation behaviors of the strut were investigated numerically and experimentally. The experimental results demonstrated that, under conditions of maximum temperature of ∼2800 K and maximum transient heat flux of ∼6 2, only minor scouring marks were found at specific locations on the composite leading edge of the strut. Microscopic morphology analysis revealed that the ablation damage to the strut was predominantly concentrated at the leading edge stagnation point, with the maximum ablation depth being approximately 760 . Furthermore, the solid-phase HfO2 produced by the oxidation of ultra-high temperature phases such as HfC and HfB2 can effectively fix the SiO2 in the oxide layer, thereby reducing the ablation rate of the leading edge.
{"title":"Heat transfer and ablation behaviors of the C/SiC-HfB2-HfC composite leading-edge strut in hypersonic air-breathing engine combustor environment","authors":"Zheng Zhao , Jiangyi He , Running Wang , Tingting Jing , Xing Sun , Jiaping Zhang","doi":"10.1016/j.ijheatfluidflow.2026.110261","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110261","url":null,"abstract":"<div><div>Struts are usually adopted in hypersonic engines for efficient fuel injection. Sufficient thermal protection is need for injection struts under extremely high temperature gas scouring environment. The objective of this study is to verify the reliability of the C/SiC-HfB<sub>2</sub>-HfC composite leading-edge strut under Ma6 engine combustor operation conditions. The heat transfer and ablation behaviors of the strut were investigated numerically and experimentally. The experimental results demonstrated that, under conditions of maximum temperature of ∼2800 K and maximum transient heat flux of ∼6 <span><math><mrow><mi>M</mi><mi>W</mi><mo>/</mo><mi>m</mi></mrow></math></span> <sup>2</sup>, only minor scouring marks were found at specific locations on the composite leading edge of the strut. Microscopic morphology analysis revealed that the ablation damage to the strut was predominantly concentrated at the leading edge stagnation point, with the maximum ablation depth being approximately 760 <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span>. Furthermore, the solid-phase HfO<sub>2</sub> produced by the oxidation of ultra-high temperature phases such as HfC and HfB<sub>2</sub> can effectively fix the SiO<sub>2</sub> in the oxide layer, thereby reducing the ablation rate of the leading edge.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110261"},"PeriodicalIF":2.6,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974048","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}
The direct internally reformed solid oxide fuel cell (DIR-SOFC) has the advantages of wide fuel adaptability and high power generation efficiency. Rapid performance prediction and optimization methods play a very important role in reducing performance improvement of SOFC. In this paper, a DIR-SOFC performance prediction and optimization method based on GA-optimized BP neural network was proposed. Using multi-component fuel as a case, 2060 analysis samples were established by 3D numerical simulation, and the current density and temperature of the DIR-SOFC under different fuel components were predicted and optimized by the proposed method. The results show that this method has the advantages of strong generalization ability, high prediction accuracy and fast calculation speed. Aiming for higher current density and lower maximum temperature gradient, the method is applied to achieve optimization combination of fuel components (H2O, NH3, H2, CO, CH4). At an operating voltage of 0.7 V, the optimal fuel ratio is determined as 0.6% H2O, 25.6% H2, 29% CO, 29.4% CH4 and 15.4% NH3. The current density is 3336 A·m−2 and the maximum temperature gradient is 169618 K·m−1. In addition, the weight analysis method was used to study the influence degree of fuel composition on power generation performance. It is found that increasing the volume fraction of H2O and NH3 in the fuel reduces the power generation performance, while increasing the volume fraction of H2, CO and CH4 in the fuel improves the power generation performance. Increasing the volume fraction of H2O decreases the maximum temperature gradient while other gases increase it. These conclusions are consistent with the results obtained by the prediction method, which proves the consistency of the proposed method with the physical mechanism. This study has guiding significance for optimizing the operating conditions of DIR-SOFC.
{"title":"Performance prediction and optimization method of DIR-SOFC based on GA-optimized BP neural network: A case study of multi-component fuel","authors":"Jianfei Zhang, Weiwen Chen, Guomeng Wei, Zhiguo Qu","doi":"10.1016/j.ijheatfluidflow.2026.110254","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110254","url":null,"abstract":"<div><div>The direct internally reformed solid oxide fuel cell (DIR-SOFC) has the advantages of wide fuel adaptability and high power generation efficiency. Rapid performance prediction and optimization methods play a very important role in reducing performance improvement of SOFC. In this paper, a DIR-SOFC performance prediction and optimization method based on GA-optimized BP neural network was proposed. Using multi-component fuel as a case, 2060 analysis samples were established by 3D numerical simulation, and the current density and temperature of the DIR-SOFC under different fuel components were predicted and optimized by the proposed method. The results show that this method has the advantages of strong generalization ability, high prediction accuracy and fast calculation speed. Aiming for higher current density and lower maximum temperature gradient, the method is applied to achieve optimization combination of fuel components (H<sub>2</sub>O, NH<sub>3</sub>, H<sub>2</sub>, CO, CH<sub>4</sub>). At an operating voltage of 0.7 V, the optimal fuel ratio is determined as 0.6% H<sub>2</sub>O, 25.6% H<sub>2</sub>, 29% CO, 29.4% CH<sub>4</sub> and 15.4% NH<sub>3</sub>. The current density is 3336 A·m<sup>−2</sup> and the maximum temperature gradient is 169618 K·m<sup>−1</sup>. In addition, the weight analysis method was used to study the influence degree of fuel composition on power generation performance. It is found that increasing the volume fraction of H<sub>2</sub>O and NH<sub>3</sub> in the fuel reduces the power generation performance, while increasing the volume fraction of H<sub>2</sub>, CO and CH<sub>4</sub> in the fuel improves the power generation performance. Increasing the volume fraction of H<sub>2</sub>O decreases the maximum temperature gradient while other gases increase it. These conclusions are consistent with the results obtained by the prediction method, which proves the consistency of the proposed method with the physical mechanism. This study has guiding significance for optimizing the operating conditions of DIR-SOFC.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110254"},"PeriodicalIF":2.6,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923208","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}
Pub Date : 2026-01-09DOI: 10.1016/j.ijheatfluidflow.2026.110246
Pooja Thakur , Yugal Sharma , Aruna Thakur
This study investigates the effects of flow and thermal characteristics around a circular cylinder with varying roughness heights, situated in a Bingham plastic fluid. Numerical simulations were performed across the following parameter ranges: 0.1 ≤ Re ≤ 40, 0.7 ≤ Pr ≤ 100, 0 ≤ Bn ≤ 100, and 0 ≤ ε/D ≤ 0.5. The numerical results were validated against existing literature. The analysis includes local and average drag force, streamlines, pressure contours, local and average Nusselt numbers, and isotherms. For ε/D ≤ 0.1, the drag coefficient of the rough-surfaced cylinder exceeds that of the smooth cylinder. Conversely, for ε/D > 0.1, the rough cylinder exhibits a lower drag coefficient than the smooth cylinder. The influence of roughness on the Nusselt number follows a similar pattern. These findings highlight the dependence of conduction and convection heat transfer modes on inertial forces, viscous forces, yield stress effects, and surface texture. A regression technique was employed to develop a correlation for the Nusselt number based on the numerical data, which also reveals discrepancies associated with surface roughness. Additionally, for Bingham plastic fluids, the effect of roughness on drag and the Nusselt number is negligible at low Reynolds numbers. However, for larger roughness and Reynolds numbers (ε/D = 0.1 and Re = 10), significant variations are observed.
{"title":"Investigation of heat transfer and flow structure around a grooved surface cylinder","authors":"Pooja Thakur , Yugal Sharma , Aruna Thakur","doi":"10.1016/j.ijheatfluidflow.2026.110246","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110246","url":null,"abstract":"<div><div>This study investigates the effects of flow and thermal characteristics around a circular cylinder with varying roughness heights, situated in a Bingham plastic fluid. Numerical simulations were performed across the following parameter ranges: 0.1 ≤ Re ≤ 40, 0.7 ≤ Pr ≤ 100, 0 ≤ Bn ≤ 100, and 0 ≤ ε/D ≤ 0.5. The numerical results were validated against existing literature. The analysis includes local and average drag force, streamlines, pressure contours, local and average Nusselt numbers, and isotherms. For ε/D ≤ 0.1, the drag coefficient of the rough-surfaced cylinder exceeds that of the smooth cylinder. Conversely, for ε/D > 0.1, the rough cylinder exhibits a lower drag coefficient than the smooth cylinder. The influence of roughness on the Nusselt number follows a similar pattern. These findings highlight the dependence of conduction and convection heat transfer modes on inertial forces, viscous forces, yield stress effects, and surface texture. A regression technique was employed to develop a correlation for the Nusselt number based on the numerical data, which also reveals discrepancies associated with surface roughness. Additionally, for Bingham plastic fluids, the effect of roughness on drag and the Nusselt number is negligible at low Reynolds numbers. However, for larger roughness and Reynolds numbers (ε/D = 0.1 and Re = 10), significant variations are observed.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110246"},"PeriodicalIF":2.6,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923118","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}
Pub Date : 2026-01-09DOI: 10.1016/j.ijheatfluidflow.2026.110252
Qian Wang , Pingting Chen , Xiaoqi Sun , Simou Sun , Junkui Mao
Additive manufacturing (AM) enables advanced design freedom for turbine film cooling components but concurrently introduces significant in-hole surface roughness, which critically affects cooling performance. Accurately modeling these large-scale roughness features is essential for predictive simulations, yet the validity of various modeling approaches remains insufficiently explored. This study numerically investigates three distinct roughness modeling methodologies: the equivalent sand-grain roughness (ks) method, a stepped roughness method, and an analog roughness method based on an autocorrelation function. Using Computational Fluid Dynamics (CFD), the performance of these models was benchmarked against a synthetically generated “real roughness” hole at blowing ratios (M) of 0.5, 1.0, and 1.5. Results reveal that the in-hole roughness creates asymmetric velocity distributions, altering downstream vortex structures and, in some cases, enhancing lateral average film cooling effectiveness (ηl) compared to a smooth hole. Notably, only the analog roughness model generated via the autocorrelation function successfully replicated the performance and flow physics of the “real roughness” hole. In contrast, the equivalent sand-grain and stepped roughness models predicted a degradation in cooling effectiveness, failing to capture the complex underlying flow phenomena. This work demonstrates the potential of the autocorrelation function approach as a promising tool for characterizing the aero-thermal impact of large-scale AM-induced roughness, highlighting the limitations of simpler, conventional models.
{"title":"Research on modeling In-Hole large scale roughness elements of film cooling holes to replicate film cooling performance","authors":"Qian Wang , Pingting Chen , Xiaoqi Sun , Simou Sun , Junkui Mao","doi":"10.1016/j.ijheatfluidflow.2026.110252","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110252","url":null,"abstract":"<div><div>Additive manufacturing (AM) enables advanced design freedom for turbine film cooling components but concurrently introduces significant in-hole surface roughness, which critically affects cooling performance. Accurately modeling these large-scale roughness features is essential for predictive simulations, yet the validity of various modeling approaches remains insufficiently explored. This study numerically investigates three distinct roughness modeling methodologies: the equivalent sand-grain roughness (<em>k<sub>s</sub></em>) method, a stepped roughness method, and an analog roughness method based on an autocorrelation function. Using Computational Fluid Dynamics (CFD), the performance of these models was benchmarked against a synthetically generated “real roughness” hole at blowing ratios (<em>M</em>) of 0.5, 1.0, and 1.5. Results reveal that the in-hole roughness creates asymmetric velocity distributions, altering downstream vortex structures and, in some cases, enhancing lateral average film cooling effectiveness (<em>η<sub>l</sub></em>) compared to a smooth hole. Notably, only the analog roughness model generated via the autocorrelation function successfully replicated the performance and flow physics of the “real roughness” hole. In contrast, the equivalent sand-grain and stepped roughness models predicted a degradation in cooling effectiveness, failing to capture the complex underlying flow phenomena. This work demonstrates the potential of the autocorrelation function approach as a promising tool for characterizing the aero-thermal impact of large-scale AM-induced roughness, highlighting the limitations of simpler, conventional models.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110252"},"PeriodicalIF":2.6,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923209","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}
Pub Date : 2026-01-09DOI: 10.1016/j.ijheatfluidflow.2026.110251
Shuo Wang , Lin Wan , Hongchao Wang , Gang Che , Yan Li , Tingbo Du , Chaofan Wang
To enhance the heat transfer performance of heat exchange tubes and address the research gap in the coupling of structural parameters, operating parameters, and energy efficiency indicators between Parameter Estimation (PE) and Continuous Adjoint Optimization (CADJ) in heat exchange tubes, this study focuses on the helical groove tube in a novel gas-phase rotary shell-and-tube heat exchanger. The study sequentially applies PE and CADJ methods for optimization design, resulting in a new type of highly efficient heat exchange tube. Based on the thermal performance-to-pressure drop loss ratio, Computational Fluid Dynamics software is used to quantitatively assess the heat exchange tube’s energy efficiency and systematically analyze its heat transfer characteristics. Additionally, a physics-informed neural network (PINN) is employed to solve the Navier-Stokes equations and reconstruct the two-dimensional temperature field, thereby cross-validating the CFD results in the absence of experimental validation and enhancing the robustness of the optimized design conclusions. The results indicate a strong correlation between various parameters, including tube inner diameter, groove depth, pitch, air velocity, inlet fluid temperature, and tube wall temperature, and the heat transfer characteristics, with correlation coefficients of 0.9799, 0.9957, 0.9897, and 0.9989, respectively. It was found that enhancing the Nusselt number comes at the cost of increased pressure drop. Compared to the helical groove tube, the novel heat exchanger tube exhibits superior performance in both heat transfer efficiency and energy efficiency, with improvements in the Nusselt number, pressure drop, and the ratio of thermal efficiency to pressure drop by 22.03 %, 22.88 %, and 58.51 %, respectively. The superior performance of the new heat exchanger tube is attributed to the continuous optimization of the helical groove tube’s inner wall morphology using the CADJ method, which maintains the basic structure of the internal helical ribs. This optimization strengthens the vortex flow structure while effectively preserving the smooth flow path of the fluid. Additionally, in the absence of experimental validation, the discrepancy between the PINN-reconstructed temperature field and the CFD solution remains on the order of 10−1, indicating that employing PINN for cross-validation and auxiliary assessment of CFD results provides a simple yet efficient alternative approach. This study presents a reasonable, novel, and practical optimization strategy to improve the heat transfer performance and energy efficiency of heat exchange tubes, offering significant practical application value.
{"title":"The optimized design and heat transfer characteristics of helical groove tubes: A study based on parameter estimation, continuous adjoint optimization, and physics-informed neural networks","authors":"Shuo Wang , Lin Wan , Hongchao Wang , Gang Che , Yan Li , Tingbo Du , Chaofan Wang","doi":"10.1016/j.ijheatfluidflow.2026.110251","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110251","url":null,"abstract":"<div><div>To enhance the heat transfer performance of heat exchange tubes and address the research gap in the coupling of structural parameters, operating parameters, and energy efficiency indicators between Parameter Estimation (PE) and Continuous Adjoint Optimization (CADJ) in heat exchange tubes, this study focuses on the helical groove tube in a novel gas-phase rotary shell-and-tube heat exchanger. The study sequentially applies PE and CADJ methods for optimization design, resulting in a new type of highly efficient heat exchange tube. Based on the thermal performance-to-pressure drop loss ratio, Computational Fluid Dynamics software is used to quantitatively assess the heat exchange tube’s energy efficiency and systematically analyze its heat transfer characteristics. Additionally, a physics-informed neural network (PINN) is employed to solve the Navier-Stokes equations and reconstruct the two-dimensional temperature field, thereby cross-validating the CFD results in the absence of experimental validation and enhancing the robustness of the optimized design conclusions. The results indicate a strong correlation between various parameters, including tube inner diameter, groove depth, pitch, air velocity, inlet fluid temperature, and tube wall temperature, and the heat transfer characteristics, with correlation coefficients of 0.9799, 0.9957, 0.9897, and 0.9989, respectively. It was found that enhancing the Nusselt number comes at the cost of increased pressure drop. Compared to the helical groove tube, the novel heat exchanger tube exhibits superior performance in both heat transfer efficiency and energy efficiency, with improvements in the Nusselt number, pressure drop, and the ratio of thermal efficiency to pressure drop by 22.03 %, 22.88 %, and 58.51 %, respectively. The superior performance of the new heat exchanger tube is attributed to the continuous optimization of the helical groove tube’s inner wall morphology using the CADJ method, which maintains the basic structure of the internal helical ribs. This optimization strengthens the vortex flow structure while effectively preserving the smooth flow path of the fluid. Additionally, in the absence of experimental validation, the discrepancy between the PINN-reconstructed temperature field and the CFD solution remains on the order of 10<sup>−1</sup>, indicating that employing PINN for cross-validation and auxiliary assessment of CFD results provides a simple yet efficient alternative approach. This study presents a reasonable, novel, and practical optimization strategy to improve the heat transfer performance and energy efficiency of heat exchange tubes, offering significant practical application value.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110251"},"PeriodicalIF":2.6,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923210","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}
Pub Date : 2026-01-09DOI: 10.1016/j.ijheatfluidflow.2026.110250
Tianyu Wu, Yuhao Gao, Xinxin Ren, Jianqiu Zhou
To satisfy the ever-increasing heat flux (>1 kW cm−2) of high-power microelectronics, we perform steady, laminar CFD simulations (validated against existing experiments with friction-factor deviations within 6.9 % and Nusselt-number deviations within 2.4 %) to compare three microchannel architectures: (i) straight rectangular, (ii) double-layer staggered-cavity, and (iii) staggered-cavity with circular pin–fin ribs. For the first time, systematic parametric sweeps (Re = 100–800, cavity depth = 30–70 µm, cavity-pitch-to-hydraulic-diameter ratio = 0.03–0.12) quantify the synergistic boundary-layer disruption generated by cavity-driven vortices and the jet-impingement/recirculation induced by pin fins. Compared with the straight channel, the composite design increases Nu by 9.6–19.8 % while raising the Darcy friction factor by 26–52 %. When both geometries are compared at equal pumping power (PEC), the composite channel yields superior thermo-hydraulic performance below Re ≈ 300 (maximum PEC = 1.13 at Re = 300, depth = 60 µm, pitch/Dh = 0.06), whereas the cavity-only configuration becomes advantageous at higher Reynolds numbers, offering clear design guidelines for practical applications.
{"title":"Numerical investigation on compound heat-transfer enhancement in pin-fin-enhanced double-layer staggered-cavity microchannels","authors":"Tianyu Wu, Yuhao Gao, Xinxin Ren, Jianqiu Zhou","doi":"10.1016/j.ijheatfluidflow.2026.110250","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110250","url":null,"abstract":"<div><div>To satisfy the ever-increasing heat flux (>1 kW cm<sup>−2</sup>) of high-power microelectronics, we perform steady, laminar CFD simulations (validated against existing experiments with friction-factor deviations within 6.9 % and Nusselt-number deviations within 2.4 %) to compare three microchannel architectures: (i) straight rectangular, (ii) double-layer staggered-cavity, and (iii) staggered-cavity with circular pin–fin ribs. For the first time, systematic parametric sweeps (Re = 100–800, cavity depth = 30–70 µm, cavity-pitch-to-hydraulic-diameter ratio = 0.03–0.12) quantify the synergistic boundary-layer disruption generated by cavity-driven vortices and the jet-impingement/recirculation induced by pin fins. Compared with the straight channel, the composite design increases <em>Nu</em> by 9.6–19.8 % while raising the Darcy friction factor by 26–52 %. When both geometries are compared at equal pumping power (PEC), the composite channel yields superior thermo-hydraulic performance below Re ≈ 300 (maximum PEC = 1.13 at Re = 300, depth = 60 µm, pitch/D<sub>h</sub> = 0.06), whereas the cavity-only configuration becomes advantageous at higher Reynolds numbers, offering clear design guidelines for practical applications.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110250"},"PeriodicalIF":2.6,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923204","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}
This paper presents a numerical study of the flow and heat transfer performance of a trapezoidal cavity rib-double rectangular circular fin microchannel heat sink (TR-DRRF) combined with a pulsating fluid. The SIMPLEC algorithm is adopted for the pressure–velocity coupling using second order upwind discretization equations. The TR-DRRF microchannel is analyzed in comparison with straight rectangular microchannel (SR), trapezoidal cavity fin microchannel (TR) and trapezoidal cavity fin-single rectangular circular fin microchannel (TR-SRRF). Results indicate that the dual rectangular circular fins of the TR-DRRF significantly increase the fluid–solid interface area, disrupt thermal boundary layer development, and alter flow field distribution. At Reynolds number (Re) = 400, its maximum temperature () is reduced by 48 K, 15.8 K, and 5.96 K compared to SR, TR, and TR-SRRF, respectively. while the Nusselt number (Nu) increased by 88.72%, 41.76%, and 13.03%, respectively. The performance evaluation criterion (PEC) improved by over 7% compared to the other three designs. The introduction of pulsating flow significantly enhances the overall thermal performance of TR-DRRF compared to steady flow at the same Re number. The core mechanism involves the sustained development of the flow boundary layer and the generation of secondary flow/counterflow. Among these, square-wave pulsed flow exhibits the most effective heat transfer enhancement. Pulsation parameters exert distinct effects: frequencies in the range of 0.2–5 Hz impair heat transfer, whereas those in the range of 5–70 Hz enhance it. Increasing frequency enhances overall heat dissipation performance (PEC outperforms steady flow at f 10 Hz). Increasing amplitude (0.2–1.2 m/s) enhances heat transfer (reducing by up to 2.1 K) but increases pressure loss. Only when amplitude 0.7 m/s does the overall performance surpass steady flow.
{"title":"Numerical study of flow and heat transfer performance in a novel microchannel under pulsating flow conditions","authors":"Chunquan Li, Jirong Huang, Yilong Hu, Cailin Li, Hongyan Huang","doi":"10.1016/j.ijheatfluidflow.2025.110228","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110228","url":null,"abstract":"<div><div>This paper presents a numerical study of the flow and heat transfer performance of a trapezoidal cavity rib-double rectangular circular fin microchannel heat sink (TR-DRRF) combined with a pulsating fluid. The SIMPLEC algorithm is adopted for the pressure–velocity coupling using second order upwind discretization equations. The TR-DRRF microchannel is analyzed in comparison with straight rectangular microchannel (SR), trapezoidal cavity fin microchannel (TR) and trapezoidal cavity fin-single rectangular circular fin microchannel (TR-SRRF). Results indicate that the dual rectangular circular fins of the TR-DRRF significantly increase the fluid–solid interface area, disrupt thermal boundary layer development, and alter flow field distribution. At Reynolds number (Re) = 400, its maximum temperature (<span><math><msub><mrow><mi>T</mi></mrow><mrow><msub><mrow></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></mrow></msub></math></span>) is reduced by 48 K, 15.8 K, and 5.96 K compared to SR, TR, and TR-SRRF, respectively. while the Nusselt number (Nu) increased by 88.72%, 41.76%, and 13.03%, respectively. The performance evaluation criterion (PEC) improved by over 7% compared to the other three designs. The introduction of pulsating flow significantly enhances the overall thermal performance of TR-DRRF compared to steady flow at the same Re number. The core mechanism involves the sustained development of the flow boundary layer and the generation of secondary flow/counterflow. Among these, square-wave pulsed flow exhibits the most effective heat transfer enhancement. Pulsation parameters exert distinct effects: frequencies in the range of 0.2–5 Hz impair heat transfer, whereas those in the range of 5–70 Hz enhance it. Increasing frequency enhances overall heat dissipation performance (PEC outperforms steady flow at f <span><math><mo>></mo></math></span> 10 Hz). Increasing amplitude (0.2–1.2 m/s) enhances heat transfer (reducing <span><math><msub><mrow><mi>T</mi></mrow><mrow><msub><mrow></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></mrow></msub></math></span> by up to 2.1 K) but increases pressure loss. Only when amplitude <span><math><mo><</mo></math></span> 0.7 m/s does the overall performance surpass steady flow.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110228"},"PeriodicalIF":2.6,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923122","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}
Pub Date : 2026-01-08DOI: 10.1016/j.ijheatfluidflow.2026.110235
Yulin Zhang , Yanwei Wu , Leihu Shen , Zixuan Wang , Xia Weng , Jiaqi Li
Low-saturation pressure dielectric liquids are increasingly used in dielectric cooling systems, such as automotive and data center applications. The development of low-GWP refrigerants has introduced some with higher surface tension, which may significantly affect the heat transfer characteristics of the flow boiling process. This study systematically investigates the flow boiling heat transfer behavior of LC-50, a high surface tension, environmentally friendly dielectric liquid, in smooth horizontal copper tubes under varying heat flux, mass flux, saturation pressure, and tube diameter conditions, comparing its flow regimes and heat transfer performance with HFE-7100. The results show, as vapor quality increases, flow regimes transition from plug flow to slug flow to annular flow. Heat flux significantly influences nucleate boiling intensity, while mass flux accelerates flow regime transitions and enhances flow disturbance. Saturation pressure alters vapor properties, affecting heat transfer. Larger tube diameter weakens thin liquid film evaporation, delaying dryout. Increased surface tension suppresses heat transfer in nucleate boiling, while liquid film stability is key in dryout. Using the experimental database, the Kandlikar correlation was improved, achieving a mean absolute error of 7.37 % over 204 data points under 68 conditions, with 95.09 % of predictions within ± 15 % of experimental values. These results provide a foundation for the study of dielectric Liquids in flow boiling applications and offer guidance for future thermodynamic cycle designs in dielectric scenarios.
{"title":"Experimental investigation of flow boiling heat transfer characteristics of eco-friendly dielectric liquid in horizontal tubes","authors":"Yulin Zhang , Yanwei Wu , Leihu Shen , Zixuan Wang , Xia Weng , Jiaqi Li","doi":"10.1016/j.ijheatfluidflow.2026.110235","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110235","url":null,"abstract":"<div><div>Low-saturation pressure dielectric liquids are increasingly used in dielectric cooling systems, such as automotive and data center applications. The development of low-GWP refrigerants has introduced some with higher surface tension, which may significantly affect the heat transfer characteristics of the flow boiling process. This study systematically investigates the flow boiling heat transfer behavior of LC-50, a high surface tension, environmentally friendly dielectric liquid, in smooth horizontal copper tubes under varying heat flux, mass flux, saturation pressure, and tube diameter conditions, comparing its flow regimes and heat transfer performance with HFE-7100. The results show, as vapor quality increases, flow regimes transition from plug flow to slug flow to annular flow. Heat flux significantly influences nucleate boiling intensity, while mass flux accelerates flow regime transitions and enhances flow disturbance. Saturation pressure alters vapor properties, affecting heat transfer. Larger tube diameter weakens thin liquid film evaporation, delaying dryout. Increased surface tension suppresses heat transfer in nucleate boiling, while liquid film stability is key in dryout. Using the experimental database, the Kandlikar correlation was improved, achieving a mean absolute error of 7.37 % over 204 data points under 68 conditions, with 95.09 % of predictions within ± 15 % of experimental values. These results provide a foundation for the study of dielectric Liquids in flow boiling applications and offer guidance for future thermodynamic cycle designs in dielectric scenarios.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110235"},"PeriodicalIF":2.6,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923119","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}
Minimizing the entropy generation and pressure drop penalty during heat transfer has been a prime concern in the design of heat sinks. One way to mitigate this is to include slots in the pin fin heat sink design, which not only improves the overall heat transfer but also reduces these penalties. Present study numerically investigates the impact of six different slot designs on the conventional pin fin structure, which are venturi, circular cavity, sudden expansion, sudden contraction, linear divergence, and linear convergence. A three-dimensional computational fluid dynamics (CFD) model is used to validate the experimental investigation of a cylindrical pin–fin heat sink, considering four Reynolds numbers ranging from 8,547 to 21,367. Later, the model is utilized to examine different slot-inserted square-shaped fin structures to study the overall performance based on Nusselt number, pressure drop across the heat sink, hydrothermal performance factor (HTPF), thermal resistance, and total entropy generation. Among the six different slots, the venturi slot (VS) outperformed the rest. This configuration reports a 33.6% increase and a 29.03% decrease in HTPF and total entropy generation, respectively. As a follow-up, the VS is applied in the cylindrical pin fin (CPF) to understand the influence of the principal fin design on effective heat transfer.
{"title":"Optimizing slot design in pin-fin heat sinks: a numerical approach to lower entropy and pressure drop","authors":"Md Ishtiaque Hossain , Md Samiul Haider Chowdhury , Md. Shahjahan Durjoy , Syed Shaheer Uddin Ahmed , Istiaq Jamil Siddique","doi":"10.1016/j.ijheatfluidflow.2025.110226","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110226","url":null,"abstract":"<div><div>Minimizing the entropy generation and pressure drop penalty during heat transfer has been a prime concern in the design of heat sinks. One way to mitigate this is to include slots in the pin fin heat sink design, which not only improves the overall heat transfer but also reduces these penalties. Present study numerically investigates the impact of six different slot designs on the conventional pin fin structure, which are venturi, circular cavity, sudden expansion, sudden contraction, linear divergence, and linear convergence. A three-dimensional computational fluid dynamics (CFD) model is used to validate the experimental investigation of a cylindrical pin–fin heat sink, considering four Reynolds numbers ranging from 8,547 to 21,367. Later, the model is utilized to examine different slot-inserted square-shaped fin structures to study the overall performance based on Nusselt number, pressure drop across the heat sink, hydrothermal performance factor (HTPF), thermal resistance, and total entropy generation. Among the six different slots, the venturi slot (VS) outperformed the rest. This configuration reports a 33.6% increase and a 29.03% decrease in HTPF and total entropy generation, respectively. As a follow-up, the VS is applied in the cylindrical pin fin (CPF) to understand the influence of the principal fin design on effective heat transfer.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110226"},"PeriodicalIF":2.6,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923120","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}
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