International Journal of Heat and Fluid Flow最新文献

{"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 ,&nbsp;Jiangyi He ,&nbsp;Running Wang ,&nbsp;Tingting Jing ,&nbsp;Xing Sun ,&nbsp;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-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 <span><math><mrow><mi>M</mi><mi>W</mi><mo>/</mo><mi>m</mi></mrow></math></span> 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 <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span>. 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.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110261"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","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}

{"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,&nbsp;Weiwen Chen,&nbsp;Guomeng Wei,&nbsp;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 (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.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110254"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","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}

{"title":"Investigation into the effects of crimp morphology on heat transfer and flow of high-frequency welded finned tubes","authors":"Chunxue Zhang ,&nbsp;Wenchun Jiang ,&nbsp;Huibo Meng ,&nbsp;Yiliang Jia ,&nbsp;Yucai Zhang ,&nbsp;Shan-Tung Tu","doi":"10.1016/j.ijheatfluidflow.2026.110296","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110296","url":null,"abstract":"<div><div>Crimped spiral finned tubes (CSFTs) are increasingly adopted in air coolers owing to advances in high-frequency resistance welding technology. Targeting the unique crimped morphology of CSFTs, this study innovatively quantifies the effects of crimping parameters on heat transfer and flow resistance, while simultaneously examining the influence of fin pitch and fin thickness on both plain spiral finned tubes (PSFTs) and CSFTs. Results show that PSFTs benefit more from fin pitch optimization, achieving up to 16.8% enhancement in <em>Nu</em> and 13.8% in the comprehensive performance index <em>ζ</em>, whereas CSFTs exhibit only marginal improvements accompanied by higher frictional losses. Nevertheless, introducing crimp amplitude <em>C_a</em> and crimp frequency <em>C_fd</em> enables further enhancement for CSFTs. Variance analysis demonstrates that <em>C_a</em> and <em>C_fd</em> contribute almost equally to <em>Nu</em> (48.7% vs. 47.8%), whereas <em>C_a</em> imposes a stronger penalty on the friction factor <em>f</em>. Considering the trade-off between amplitude and frequency imposed by manufacturing constraints, a novel optimization strategy is proposed: prioritize increasing crimp frequency while appropriately limiting crimp amplitude. In addition, predictive models for <em>Nu</em> and <em>f</em> are established using <em>Re</em>, fin pitch, fin thickness, <em>C_a</em> and <em>C_fd</em> as inputs. Artificial neural networks outperform regression models, with prediction errors below 5%, demonstrating strong accuracy and practical applicabilit. This study provides practical guidance into heat transfer enhancement for high-efficiency heat exchange systems employing CSFTs.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110296"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170485","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":"Numerical modelling of heat and mass transfer during vapour condensation in porous media: Insights from neutron tomography","authors":"Arash Nemati ,&nbsp;Philippe Séchet ,&nbsp;Bratislav Lukić ,&nbsp;Matthieu Briffaut","doi":"10.1016/j.ijheatfluidflow.2026.110293","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110293","url":null,"abstract":"<div><div>Moisture condensation in porous media influences heat and mass transport in natural and engineered systems, with implications for energy, environmental, and material applications. This study presents a new framework for analysing coupled heat and mass transfer during vapour condensation in porous materials. The Darcy-scale model, formulated under local thermal equilibrium, incorporates multiphase flow, phase change, and heat transport through standard capillary and permeability relationships. A finite-volume solver was implemented in OpenFOAM to couple heat and vapour transport via a temperature-dependent vapour saturation relationship. An analytical solution for the immobile case, where the condensed liquid remains stationary, defines an effective Péclet number that quantifies the competition between advective and diffusive transport of both heat and vapour. Together with the capillary number (relevant in mobile regimes), representing the balance between pressure and capillary forces, these parameters help classify the condensation regimes. Simulation results reveal that near the condensation front, water flux is driven by capillarity, while farther behind, pressure gradients from vapour injection dominate. Higher effective Péclet numbers yield sharper condensation fronts, while higher capillary numbers enhance liquid spreading near the front. Validation using time-resolved neutron tomography and prior numerical results confirms the ability of the model to capture key condensation mechanisms. The framework also extends to heterogeneous media with fractures, where condensation concentrates near the fracture and gradually diffuses into the surrounding matrix.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110293"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073597","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":"Investigation of thermal–hydraulic characteristics of cut-out type flying-wing fins","authors":"Xin Qi ,&nbsp;Pengcheng Zheng ,&nbsp;Zipei Zhang ,&nbsp;Wenqiang Suo ,&nbsp;Shiqun Liu ,&nbsp;Xiangshu Lei ,&nbsp;Aiyan Li ,&nbsp;Peng Yang ,&nbsp;Yingwen Liu","doi":"10.1016/j.ijheatfluidflow.2026.110290","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110290","url":null,"abstract":"<div><div>The study investigates the potential of a cut-out structure to enhance the heat transfer and flow characteristics of fins in the flying-wing condenser for refrigerator. The proposed cut-out structure is designed to address the limitations of conventional methods for strengthening heat transfer accompanied by an increase in flow resistance. The introduction of a cut-out structure facilitates the flow of cooling air from the front part to the rear area of the fins, thereby enhancing the heat transfer efficiency for rear fins. Additionally, it minimizes the collision between the airflow and the fins, enabling the flying-wing fins to achieve augmented heat transfer and reduced flow resistance simultaneously. The findings of the study demonstrate that the heat exchange rate of the flying-wing fins is enhanced by 7% and the flow resistance is reduced by 20.8% following the integration of the cut-out. Concurrently, an augmentation in the cut-out height and length of the fins resulted in a concurrent decrease in both heat exchange rate and flow resistance. Furthermore, an analysis of the field synergy angle and local convective heat transfer coefficient (LCHTC) of the different cut-out type flying-wing fins reveals that the introduction of the cut-out leads to a significant enhancement in the synergy between the velocity field and the temperature field. Concurrently, the LCHTC exhibits a “high and low” distribution pattern within the fin channel, with the LCHTC on the right side being notably higher than that on the left side.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110290"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146169957","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":"Probing exponential disjoining pressure in thin films via wettability and sub-atmospheric pressure: An experimental study","authors":"Junhe Wang ,&nbsp;Yongxin Liu ,&nbsp;Tengxiao Ma ,&nbsp;Leping Zhou ,&nbsp;Xiaoze Du","doi":"10.1016/j.ijheatfluidflow.2026.110297","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110297","url":null,"abstract":"<div><div>The stability and transport of nanoscale liquid films under reduced pressure are critical for space thermal management, yet remain poorly understood as classical interfacial theories assume standard atmospheric conditions. This study presents the first systematic experimental investigation of disjoining pressure (<em>P_d</em>) isotherms under low pressure (50–90 kPa) across a broad wettability spectrum (contact angles: 4.18° to 99.11°). Utilizing a novel dual-chamber system that integrates a vacuum-controlled Sheludko cell with multilayer nanoparticle image velocimetry, we simultaneously mapped film thickness and disjoining pressure. It was discovered that reducing pressure induces a fundamental departure from DLVO theory: the equilibrium film thickness increases linearly, while the scaling exponent <em>B</em> in <em>P_d</em> ∼ <em>δ</em>⁻<em>^B</em> grows exponentially to values up to 23.5, which is far exceeding the classical limit of 3 for van der Waals forces. Furthermore, hydrophobic surfaces exhibited a pressure-amplified enhancement of the effective Hamaker constant, correlating with superior evaporation suppression despite minimal film thickness. These findings reveal strong non-classical interfacial thermodynamics in low-pressure environments and establish a new foundation for designing advanced thermal management systems, such as microgravity heat pipes and passive cooling surfaces for planetary habitats.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110297"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170016","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":"Outer-layer similarity from the perspective of uniform momentum zones in turbulent boundary layer over smooth and rough wall","authors":"Zichun Zhang ,&nbsp;Zexin Feng ,&nbsp;Kebing Huo ,&nbsp;Nan Jiang","doi":"10.1016/j.ijheatfluidflow.2026.110292","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110292","url":null,"abstract":"<div><div>The study investigates outer-layer similarity in turbulent boundary layers (TBLs) over smooth and rough walls through the lens of uniform momentum zones (UMZs), measured via two-dimensional particle image velocimetry (PIV) in the streamwise-wall-normal plane at moderate Reynolds numbers. Preliminary analyses of first-order and second-order statistics confirm the broad consistency of outer-layer dynamics across both wall conditions. The turbulent/non-turbulent interface (TNTI) and associated intermittency were examined in both cases, revealing a region of higher intermittency and a thicker boundary layer in the rough-wall case. Despite these differences, the multiple UMZs observed over both surfaces exhibit comparable structural features, consistent with the expectations of outer-layer similarity. A comparative assessment of UMZ geometrical properties—including modal velocity, interface height, and zone thickness—was conducted under two classification schemes. The observed hierarchical arrangement, where thinner near-wall UMZs evolve into thicker outer-layer zones with higher modal velocities, follows a consistent trend for both surfaces. Further insight was obtained by employing conditional averaging with respect to <em>N_UMZ</em>, highlighting both the similarities and deviations in mean velocity, Reynolds stress, dissipation, and production, particularly within the logarithmic region. Quadrant analysis reveals that ejection (Q2) and sweep (Q4) events in rough-wall TBLs exhibit altered scale interactions between small-scale and large-scale motions compared to their smooth-wall counterparts. Two-point conditional correlation analyses stratified by <em>N_UMZ</em> further delineate the spatial organization of coherent structures in both near-wall and outer regions, reinforcing the perspective of outer-layer similarity. Our research advances an innovative structural interpretation of the similarity hypothesis, offering a refined framework for examining universality in wall turbulence.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110292"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170017","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":"Optimizing slot design in pin-fin heat sinks: a numerical approach to lower entropy and pressure drop","authors":"Md Ishtiaque Hossain ,&nbsp;Md Samiul Haider Chowdhury ,&nbsp;Md. Shahjahan Durjoy ,&nbsp;Syed Shaheer Uddin Ahmed ,&nbsp;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":"2026-04-01","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}

{"title":"Heat transfer characteristics of nonlinearly graded metal foam in thermal storage tank: A novel framework model of BP neural network fused with tactical unit algorithm","authors":"Jiayi Gao ,&nbsp;Xinyu Gao ,&nbsp;Yuanji Li ,&nbsp;Xiaohu Yang ,&nbsp;Ya-Ling He","doi":"10.1016/j.ijheatfluidflow.2026.110236","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110236","url":null,"abstract":"<div><div>Metal foams (MF) are widely used in phase change materials (PCMs) due to their high thermal conductivity, high porosity and large specific surface area. These characteristics jointly improve the thermal performance of PCMs. This study investigates the influence of porosity variation (ranging from 0.85 to 0.96) on the thermal behavior of a phase change thermal storage (PCTS) unit. The research finds that while the reduction of porosity significantly improves the heat storage efficiency, it concurrently reduces the overall storage capacity. Specifically, compared to a porosity of 0.96, a porosity of 0.85 leads to a 71.06% increase in efficiency but is accompanied by a 10.51% decrease in capacity. To further optimize the prediction performance, an improved Tactical Unit Algorithm (ITUA), incorporating elite retention, Lévy flight, and Gaussian mutation strategies, is proposed. Compared to conventional algorithms, ITUA exhibits markedly enhanced optimization performance. Furthermore, ITUA is integrated with a backpropagation artificial neural network (BP-ANN) to develop a model of liquid phase distribution during the melting process. To maintain heat storage capacity while enhancing efficiency, both linear and nonlinear porosity distributions are investigated. At an average porosity of 0.95, energy storage efficiency is increased by 58.46% and 68.95% for linear and nonlinear arrangements, respectively, relative to uniform porosity distribution. The proposed model provides valuable guidance for optimizing MF porosity configuration in PCTS systems.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110236"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923206","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":"Numerical simulation of thermal counterflow in superfluid helium: converging/diverging, hyperbolic/elliptical, and forward/backward steps channels","authors":"Hamid Yousefi,&nbsp;Hossein Afshin","doi":"10.1016/j.ijheatfluidflow.2026.110262","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110262","url":null,"abstract":"<div><div>In this study, the thermal counterflow of superfluid helium is numerically simulated within converging/diverging, hyperbolic/elliptic, and forward/backward step channels —all possessing identical length and volume— in order to gain deeper insight into how channel geometry influences heat transport, thereby supporting improved engineering and design of high-performance heat exchangers. Simulations were performed using the two-fluid model incorporating the Gorter-Mellink mutual friction formulation under varying ratios of maximum to minimum channel height. The newly developed Super-PIMPLE algorithm—previously proposed for coupling the momentum equations of the components with pressure—has also been employed here. Unlike many similar studies, common simplifications have been avoided, and the results have been validated through a four-stage verification process. Key performance indicators, including maximum temperature difference, thermal resistance, effective thermal conductivity, pressure drop, maximum Reynolds number, component velocity difference, and density ratio, were evaluated and compared across the different geometries. The results indicate that, in general, the straight channel yields the lowest thermal gradient (i.e., minimal thermal resistance and highest effective thermal conductivity). When low thermal resistance is prioritized, but a straight channel is not feasible, the elliptic geometry proves to be a more suitable choice. Furthermore, when the cross-section of the heat flux input is not aligned with the isothermal cross-section, it is preferable for the heat flux to be applied at the smaller cross-sectional area; in such cases, step geometries are more advantageous than nozzles/diffusers. The maximum temperature difference in the nozzle geometry is approximately 16.8 times greater, and in the elliptic channel, approximately 3.8 times greater than that of the straight channel. While all non-straight configurations generally exhibit higher pressure drop compared to the straight channel, a notable exception occurs in the hyperbolic geometry. In certain cases, due to the suppression of vortices and oscillatory flows, the pressure drop is reduced by about 64.9% compared to the straight channel. Overall, when minimizing pressure drop is the primary objective, the hyperbolic channel is preferable to the straight geometry. The highest component velocity difference and mutual friction were observed in the converging channel. In nozzle and backward-step geometries, the mean temperature is higher, and the normal fluid fraction is more dominant.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110262"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073598","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}