International Journal of Heat and Mass Transfer最新文献

{"title":"MHD stagnation point flow of Casson hybrid nanofluid with bioconvection for biomedical skin patch applications","authors":"Umar Farooq , Tao Liu , Ali Alshamrani , Umer Farooq","doi":"10.1016/j.ijheatmasstransfer.2025.127048","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127048","url":null,"abstract":"<div><div>This study investigates the magnetohydrodynamic (MHD) stagnation point flow of a Casson hybrid nanofluid across a stretchable surface, with applications in biomedical fields such as thermal management in skin patches. The research addresses the critical need for efficient heat and mass transfer in medical applications by utilizing a hybrid nanofluid composed of magnesium oxide <span><math><mrow><mo>(</mo><mrow><mi>M</mi><mi>g</mi><mi>O</mi></mrow><mo>)</mo></mrow></math></span> and silicon dioxide <span><math><mrow><mo>(</mo><mrow><mi>S</mi><mi>i</mi><msub><mi>O</mi><mn>2</mn></msub></mrow><mo>)</mo></mrow></math></span> nanoparticles dispersed in blood as the base fluid. These nanoparticles are chosen for their biocompatibility, cost-effectiveness, and ability to enhance heat and mass transfer properties. The study incorporates the CattaneoChristov double diffusion model alongside the bioconvection phenomenon and effects of magnetic strength, thermal radiation, viscous dissipation, and chemical reactions. The governing partial differential equations (PDEs) are transformed into nonlinear ordinary differential equations (ODEs) using similarity transformations and solved numerically using the BVP4C algorithm with a three-stage Lobatto method. The following dimensionless parameter ranges are considered: Casson parameter <span><math><mrow><mo>(</mo><mi>β</mi><mo>)</mo></mrow></math></span> from 1 to 7, magnetic strength <span><math><mrow><mo>(</mo><mi>M</mi><mo>)</mo></mrow></math></span> from 0.01 to 0.18, Eckert number <span><math><mrow><mo>(</mo><mtext>Ec</mtext><mo>)</mo></mrow></math></span> from 0.5 to 2, radiation parameter <span><math><mrow><mo>(</mo><mtext>Rd</mtext><mo>)</mo></mrow></math></span> from 0.3 to 1.2, Schmidt number <span><math><mrow><mo>(</mo><mrow><mi>S</mi><mi>c</mi></mrow><mo>)</mo></mrow></math></span> from 1 to 2.5, and chemical reaction parameter <span><math><mrow><mo>(</mo><mi>κ</mi><mo>)</mo></mrow></math></span> from 0.5 to 0.8. Key findings demonstrate that the temperature distribution increases with the <span><math><mtext>Ec</mtext></math></span>, while the velocity profile decreases with higher <span><math><mi>β</mi></math></span> values. The study also highlights that hybrid nanofluids significantly reduce drag force by 34–39 % for Casson parameter values (<span><math><mi>β</mi></math></span> =1, 3, 5). Additionally, the Nusselt number shows a substantial enhancement of 50–72 % for specific ranges of the Brinkman number (<span><math><mtext>Br</mtext></math></span> = 1–3) and radiation parameter (<span><math><mtext>Rd</mtext></math></span> = 0.3–0.9), with a maximum increase of 72.69 %. Response surface methodology and sensitivity analysis are conducted to quantify the sensitivity caused by input data such as the <span><math><mrow><mi>β</mi><mo>,</mo><mrow><mspace></mspace><mtext>Ec</mtext></mrow><mo>,</mo></mrow></math></span> and <span><math><mi>κ</mi></math></span>. The results demonstrate that the coef","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"245 ","pages":"Article 127048"},"PeriodicalIF":5.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of an intermediate layer on immiscible viscous fingering instability in radial Hele-Shaw cell","authors":"Priya Verma ,&nbsp;Shih-Wei Hung ,&nbsp;Jia-Jun Mao ,&nbsp;Ching-Yao Chen","doi":"10.1016/j.ijheatmasstransfer.2025.127010","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127010","url":null,"abstract":"<div><div>We examine viscous fingering instability in a Hele-Shaw cell involving immiscible fluids with a three-layer fluid–fluid interface for radial flow, experimentally. The impact of introducing an intermediate layer on flow dynamics is explored, with particular attention to viscosity profiles. Our findings reveal that if the intermediate layer creates a non-monotonic viscosity profile, it significantly enhances the instability, leading to denser and more elongated fingering patterns. In particular, when the intermediate layer exhibits maximum viscosity, the growth of fingering patterns is suppressed after penetrating the intermediate layer, causing them to coalesce into a connected region. Key flow parameters such as the viscosity of the intermediate layer and the injection rate, strongly influence instability. Lowering the values of these parameters delays the suppression of instability. However, the injection volume of the intermediate layer decides whether the suppression of instability occurs. In contrast, when the intermediate layer has minimum viscosity, fingering patterns experience continuous growth with an early breakthrough. On the other hand, monotonic viscosity profiles result in less unstable flows due to smoother viscosity contrasts, causing the fingering patterns to channel and form less unstable configurations. These insights advance understanding of the interplay between viscosity profiles and flow parameters in controlling interfacial instabilities. The findings apply to CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-enhanced oil recovery and groundwater remediation, offering strategies to optimize fluid displacement processes by tailoring flow conditions and viscosity contrasts.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"245 ","pages":"Article 127010"},"PeriodicalIF":5.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Falling film heat transfer from sensible convection to boiling on horizontal tubes: Database construction and machine learning-based heat transfer prediction","authors":"Chen-Min Zheng ,&nbsp;Chuang-Yao Zhao ,&nbsp;Wei Xiao ,&nbsp;Bing-Ye Song ,&nbsp;Di Qi ,&nbsp;Jun-Min Jiang","doi":"10.1016/j.ijheatmasstransfer.2025.127020","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127020","url":null,"abstract":"<div><div>Accurate predictions of heat transfer coefficients are essential for falling film evaporators’ optimum design and heat transfer enhancement. However, the complex interplay of mechanisms and various influencing factors, poses challenges for existing prediction methods. In this study, three general consolidated databases based on comprehensive reviews of relevant published literature were constructed, following which, artificial neural network (ANN) models employing the backpropagation (BP) algorithm were developed to predict falling film heat transfer coefficients in sensible convection, evaporation, and boiling. The sensible convection database comprises 1635 data of water and alcoholic fluids, the evaporation database contains 2097 data of water, R22, and ammonia, and the boiling database consists of 1207 data involving water, R134a, R123, R11, R32, R290, R600a, R1234ze, and R245fa. An optimal ANN model was selected for prediction of the test dataset after evaluating impacts of neural network architectures and parameter combinations on the model performance. The mean absolute errors (<em>MAE</em>s) of three databases are 1.29 %, 1.09 %, and 5.02 %, respectively, with coefficient of determination (<em>R</em>²) of 0.9177, 0.9236, and 0.9637, respectively. Sensitivity analyses of the input parameters were performed to strengthen the interpretability of the model's construction. The superiority of the present optimal ANN model was revealed through comparisons with published correlations. Furthermore, the prediction capability of the present model for entirely new and unfamiliar data was assessed, demonstrating its substantial generalization capability.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"245 ","pages":"Article 127020"},"PeriodicalIF":5.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity analysis and modeling uncertainties quantification for impinging-film cooling via active subspaces","authors":"Jieli Wei ,&nbsp;Nana Wang ,&nbsp;Jingyu Zhang ,&nbsp;Xiaomin He","doi":"10.1016/j.ijheatmasstransfer.2025.127046","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127046","url":null,"abstract":"<div><div>Within the context of exploiting efficient cooling methods for advanced gas turbine combustors, understanding the fundamental physics for impinging-film cooling under various operational conditions is of significance. In this paper, impacts of different interaction modes between coolant and hot mainstream on the impinging-film cooling are quantitatively evaluated via active subspace (AS) method. Three interaction modes are considered, i.e., <em>a transitional flow</em> (TF), <em>a turbulent boundary layer</em> (TBL) and <em>a wall jet</em> (WJ). Sensitivities and uncertainties of cooling effectiveness <span><math><mi>η</mi></math></span> with respect to coolant mass flow rate <span><math><msub><mi>M</mi><mi>c</mi></msub></math></span> and model parameters (<span><math><mrow><msub><mi>C</mi><mi>μ</mi></msub><mo>,</mo><mspace></mspace><msub><mi>C</mi><mrow><mrow><mi>ε</mi></mrow><mn>1</mn></mrow></msub><mo>,</mo><mspace></mspace><msub><mi>C</mi><mrow><mrow><mi>ε</mi></mrow><mn>2</mn></mrow></msub><mo>,</mo><mspace></mspace><mi>P</mi><msub><mi>r</mi><mi>tw</mi></msub></mrow></math></span>) are estimated. Results show that 1-D active subspaces are sufficient to map <span><math><mi>η</mi></math></span> in TF and TBL modes while high-dimensional active subspaces are warranted for WJ mode, indicating its more complicated interaction between cold and hot flows. <span><math><mi>η</mi></math></span> is the most sensitive to and dominated by <span><math><msub><mi>M</mi><mi>c</mi></msub></math></span> especially in the slot and far fields, and turbulent effects are more significant in the near field than other places. Specifically, an increase in <span><math><msub><mi>M</mi><mi>c</mi></msub></math></span> or a decrease in turbulent level monotonously improves <span><math><mi>η</mi></math></span> in TF and TBL modes while initially increases <span><math><mi>η</mi></math></span> then reduces it for WJ mode. Further analysis of flow characteristics of WJ mode demonstrates that the reduction in <span><math><mi>η</mi></math></span> results from the strengthened impingement-induced streamwise vortexes and thereby, enhanced mixing between the coolant and mainstream. The propagation of the input uncertainty to <span><math><mi>η</mi></math></span> is space- and operational condition-dependent, consistent with the evolution of active subspaces.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"245 ","pages":"Article 127046"},"PeriodicalIF":5.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of flow dynamics and cooling performance in combined porosity structures at the leading edge of a hypersonic vehicle","authors":"Weijie Chen ,&nbsp;Yongqing Wang ,&nbsp;Shantung Tu ,&nbsp;Tiange Chu ,&nbsp;Huijuan Su ,&nbsp;Ke Wang","doi":"10.1016/j.ijheatmasstransfer.2025.126996","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126996","url":null,"abstract":"<div><div>Transpiration cooling presents significant promise for enhancing thermal protection in hypersonic vehicles. However, leading edge structures with single-homogeneous porosity (LE-SHP) frequently encounter excessive flow resistance at the stagnation point, resulting in non-uniform temperature distribution in localized regions, which adversely influences the thermal protection effectiveness. In response, a combined porosity structure (LE-GHP) based on local thermal equilibrium model was introduced in this paper. The cooling mechanism of LE-GHP at Mach 7 was analyzed using a step-by-step numerical simulation method. The effects of coolant injection rate and combined porosity distribution on coolant flow and cooling performance were investigated. Furthermore, the impact of discontinuous transpiration surfaces with varying lengths on downstream cooling performance was evaluated. The results indicate that flow resistance at the stagnation point is reduced by LE-GHP, forming a more uniform cooling gas film that significantly mitigates the thermal impact of high-enthalpy freestream on the transpiration surface. Compared to the LE-SHP, superior cooling performance with lower endothermic power under different coolant injection rates are demonstrated by LE-GHP, improving the temperature distribution uniformity of the transpiration surface by 30.56–70.79 % and increasing the average cooling efficiency of the hot surface by 11.48–13.01 %. Additionally, when the gradient porosity region ranges from 0° to 60° (<em>θ</em>=60°), the endothermic power of transpiration surface is reduced by up to 64.88 %, with a corresponding increase in the thermal protection effect on hot surface by up to 28.17 %. In comparison to <em>θ</em>=60°, the discontinuous transpiration surface with a length of 1 mm not only ensures the reliability of thermal protection material, but also improves the temperature distribution uniformity of hot surface by 18.36 %.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"245 ","pages":"Article 126996"},"PeriodicalIF":5.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing thermal performance for electric vehicle lithium-ion battery pack based on active thermal management","authors":"Tiancheng Ouyang ,&nbsp;Kanglin Zuo ,&nbsp;Zirui Wang ,&nbsp;Jiaqiang Hao ,&nbsp;Yong Chen","doi":"10.1016/j.ijheatmasstransfer.2025.127026","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127026","url":null,"abstract":"<div><div>Electric vehicles are powered by a range of batteries, with lithium batteries playing a dominant role, which is inseparable from their excellent performance. However, the high-rate of discharge leads to faster electrochemical reaction rates, generating more heat, thereby presenting a serious threat to the battery thermal management technology. In response to this challenge, a battery thermal management system (BTMS) consisting of pyrolytic graphite sheet (PGS), copper foam phase change material (CFPCM), and liquid cooling is suggested. A BTMS model is developed by coupling electrochemical and thermodynamic models with non-isothermal flow models. The model's accuracy is further confirmed through experiments, followed by a comparison of different schemes to reveal the excellent cooling performance of BTMS. Additionally, the impacts of CFPCM, flow rate, and coolant flow direction are investigated with respect to the performance of the BTMS. Finally, the model is numerically simulated with charging and discharging cycles in conjunction with real-world use, and it is found that the BTMS could maintain a very stable performance.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"245 ","pages":"Article 127026"},"PeriodicalIF":5.0,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-material isogeometric topology optimization for thermoelastic metamaterials","authors":"Zhaohui Xia ,&nbsp;Wanpeng Zhao ,&nbsp;Yingjun Wang ,&nbsp;Peng Li ,&nbsp;Mi Xiao ,&nbsp;Liang Gao","doi":"10.1016/j.ijheatmasstransfer.2025.126995","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126995","url":null,"abstract":"<div><div>The design of thermoelastic metamaterials has traditionally relied on finite element analysis. This paper introduces a high-precision isogeometric topology optimization method specifically tailored for thermoelastic metamaterials. By leveraging non-uniform rational B-spline (NURBS) basis functions within isogeometric analysis (IGA), the proposed method significantly enhances computational accuracy and efficiency. A numerical homogenization approach is integrated with IGA to evaluate the effective material properties of microstructures, enabling seamless integration with computer-aided design and computer-aided engineering. To formulate the optimization problem for thermoelastic metamaterials, a multi-material interpolation model is constructed, with a focus on minimizing the effective thermal expansion coefficient. Sensitivity analysis of the discrete multi-material variables are conducted within this framework. To overcome challenges such as convergence to local optima and the emergence of isolated ‘island’ in multi-material designs, innovative strategies are introduced, including a random density distribution technique and a variable-intensity threshold projection method. The proposed method's effectiveness and advantages are demonstrated through several two-dimensional and three-dimensional numerical examples. Furthermore, simulations performed using the commercial finite element software ANSYS validate the feasibility and robustness of the approach.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"245 ","pages":"Article 126995"},"PeriodicalIF":5.0,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat transfer dynamics of transient liquid CO2 spray cooling for replacement of conventional R134a spray cooling in laser dermatology","authors":"Zhi-Fu Zhou,&nbsp;Zhi-Zhong He,&nbsp;Xiang-Wei Lin,&nbsp;Xing-Yao Li,&nbsp;Xin-Yu Ding,&nbsp;Dong Li,&nbsp;Bin Chen","doi":"10.1016/j.ijheatmasstransfer.2025.127051","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127051","url":null,"abstract":"<div><div>To protect the epidermis from thermal injury, selective cooling is essential during laser surgery. Among many cooling techniques, cryogen spray cooling is widely applied because it can provide powerful cooling with tens of milliseconds. However, conventional R134a spray often fails to provide sufficient cooling for the darkly pigmented skins, meanwhile, R134a is not friendly to the environment due to high GWP of 1300. Liquid CO₂ spray might be an ideal solution to these problems with advantages of very low GWP of 1 and high latent heat. In this study, liquid CO₂ was used to form a low-temperature spray for rapid cooling. The spray pattern presented an explosive atomization characterized by bowl-like shape, large spray width and angle at nozzle exit due to Joule-Thompson effect. The effects of spurt duration, spray height and container pressure on surface temperature, heat flux and heat transfer coefficient were fully investigated. Results showed that Liquid CO₂ spray provided much higher cooling capacity with a maximum heat flux twice of that of R134a spray cooling. Decreasing spray height and increasing spurt duration both enhanced the heat flux and lower surface temperature in the range of 20∼40 mm and 40∼100 ms. Elevating the container pressure improved the cooling capacity at spray periphery while had little effect at spray center. Finally, three dimensionless correlations were derived to express the dynamic heat transfer of CO₂ spray cooling.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"245 ","pages":"Article 127051"},"PeriodicalIF":5.0,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of models and correlations for onset of significant void in subcooled boiling flows in channels with various geometries","authors":"Shichang Dong,&nbsp;Takashi Hibiki","doi":"10.1016/j.ijheatmasstransfer.2025.127028","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127028","url":null,"abstract":"<div><div>To achieve a deeper understanding of the prediction performance, this paper presents a comprehensive review and evaluation of existing mechanistic models and empirical correlations for the onset of significant void (OSV) in subcooled boiling for vertical upward flows based on an extensively collected database. First, 5 mechanistic models and 21 empirical correlations are summarized. Subsequently, an experimental database for thermal equilibrium vapor quality at OSV is prepared, which covers a wide range of operation conditions and comprises 448 data points from 27 sources. The models and correlations are then evaluated under low-pressure (<em>P</em> ≤ 1 MPa) and high-pressure (<em>P</em> &gt; 1 MPa) conditions in different channels based on the experimental database, and it is determined that the Saha-Zuber correlation exhibits inadequate performance in both rectangular and annular channels, while the Okawa model and the Levy model exhibit the highest prediction accuracy for low-pressure and high-pressure conditions, respectively. Meanwhile, the Okawa model also demonstrates the highest overall prediction performance among the reviewed models and correlations, with a mean-relative-error of 37.3 %. On the other hand, sensitivity analysis of key parameters reveals that the Okawa model has limitations in accurately predicting the influence of pressure and heat flux.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"245 ","pages":"Article 127028"},"PeriodicalIF":5.0,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation of external flow condensation heat transfer in horizontal tube-in-tube configuration","authors":"Jiayuan Li,&nbsp;Jayachandran K. Narayanan,&nbsp;Chirag R. Kharangate","doi":"10.1016/j.ijheatmasstransfer.2025.127044","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127044","url":null,"abstract":"<div><div>Flow condensation is an important process used to achieve heat rejection across thermal power and energy systems. Studies on tube condensation have concentrated on the condensing fluid flowing in the inner tube. However, common heat exchanger configurations like the shell-and-tube types see the condensing fluid on the outer surface of the tubes. To address this gap, in this study, we investigate the local and channel-averaged heat transfer characteristics of flow condensation happening on the exterior of a horizontal tube in the tube-in-tube configuration. An external flow condensation module is developed and tested to obtain heat transfer and flow visualization data, with PF-5060 as the condensing fluid flowing outside the tube and de-ionized water as the cooling fluid flowing inside the tube in the counter-current direction. Densely arranged thermocouples are installed on the exterior surface of the 12.7-mm outer-diameter tube and embedded within the water flow to measure variations in wall and water temperatures respectively, which determines the local heat transfer characteristics along a 683.6-mm condensation path. Flow visualization is achieved using a transparent polycarbonate plate that serves as the PF-5060 flow channel. The test conditions cover PF-5060 inlet mass velocities of 26.66 – 58.67 kg/m²·s, water mass velocities of 330.9 – 463.26 kg/m²·s, PF-5060 inlet pressures of 124.76 – 155.24 kPa, and PF-5060 inlet superheats of 4.39 – 5.63 °C. The local condensation heat transfer coefficient is highest near the upstream region and decreases monotonically in the downstream direction due to the thickening of liquid film and transition of flow regimes along the condensation path. Further, the heat transfer coefficient increases with both PF-5060 and water flow rates, with the PF-5060 showing a more pronounced effect. Pressure effects are also examined, showing the heat transfer coefficient decreases with the increase in operating pressure. Further, common correlations for internal flow condensation show underprediction in measured heat transfer coefficient for external flow condensation. Finally, flow visualization of external flow condensation reveals continuous detachment of liquid film at tube's underside, highlighting a clear distinction from the internal flow condensation.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"245 ","pages":"Article 127044"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143737974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}