International Journal of Heat and Mass Transfer最新文献

{"title":"Design Principles of Thermoelectric-Microchannel Hybrid Cooling Modules for Hotspot Thermal Management","authors":"Yuqing Wei ,&nbsp;Yifan Lei ,&nbsp;Yuhan Yao ,&nbsp;Ronggui Yang ,&nbsp;Xin Qian","doi":"10.1016/j.ijheatmasstransfer.2025.127113","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127113","url":null,"abstract":"<div><div>Hotspot thermal management is crucial for microprocessors, radial-frequency electronics, and power electronics. Hybrid cooling combining thermoelectrics and microchannels (TEC-MC) offers an effective solution for active and precise temperature control. This work develops an analytical model for predicting the heat flux, hotspot temperatures, and coefficient of performance (<span><math><mrow><mi>C</mi><mi>O</mi><mi>P</mi></mrow></math></span>) of TEC-MC hybrid coolers, by treating thermoelectrics as an adjustable thermal resistor. The model incorporates heat spreading resistances to account for both the in-plane and the cross-plane heat conduction from the hotspot, enabling computation of hotspot temperatures four orders of magnitude faster than three-dimensional finite element simulations. Our method can be seamlessly interfaced with multi-objective optimization algorithms for the co-design of TEC and MC. Results revealed intricate correlations among different parameters. An optimal thickness of thermoelectric legs is identified which scales linearly with the filling ratio of TEC when optimizing the cooling power. On the other hand, thinner thermoelectric legs are favored when optimizing <span><math><mrow><mi>C</mi><mi>O</mi><mi>P</mi></mrow></math></span>. Moreover, as the heat transfer performance of the MC heat sink improves, the reduced hot-side temperature of the TEC allows for a further decrease in TEC thickness, leading to higher <span><math><mrow><mi>C</mi><mi>O</mi><mi>P</mi></mrow></math></span>. Finally, the Pareto front is identified to quantify the trade-offs between the maximum cooling power and the optimal <span><math><mrow><mi>C</mi><mi>O</mi><mi>P</mi></mrow></math></span>. We proposed a co-design workflow and showed that simultaneously decreasing the thickness of thermoelectric legs and the thermal resistance of the MC is pivotal for achieving both high cooling power and improved <span><math><mrow><mi>C</mi><mi>O</mi><mi>P</mi></mrow></math></span>. This study offers a guideline for developing hybrid cooling systems for hotspot thermal management.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"247 ","pages":"Article 127113"},"PeriodicalIF":5.0,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859939","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 supercritical CO2 heat transfer characteristics in a three-rod bundle","authors":"Qianqian Ren ,&nbsp;Qinggang Qiu ,&nbsp;Yu Liu ,&nbsp;Yuwei Peng ,&nbsp;Peiyu Li ,&nbsp;Xiaojing Zhu","doi":"10.1016/j.ijheatmasstransfer.2025.127141","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127141","url":null,"abstract":"<div><div>The investigation of the heat transfer properties of supercritical CO₂ (SCO₂) within rod bundles is crucial for optimizing the design of the supercritical CO₂ direct-cooled reactor. This study presents an experimental study on the heat transfer characteristics of supercritical CO₂ in a three-rod bundle. The experiments were conducted under pressures ranging from 8 to 11 MPa, heat fluxes from 31 to 123 kW/m², mass fluxes from 270 to 830 kg/(m²·s), and inlet temperatures from 5 to 114 °C. The internal wall temperature of the heated rod was measured with a sliding thermocouple device. To assess the accuracy of the measurements, a validation experiment was performed by comparing the temperature readings from the sliding thermocouple with those from a fixed thermocouple over a temperature range from room temperature to 350 °C. The maximum difference between the two measurements was approximately 3 °C, confirming the reliability of the sliding thermocouple measurements. The effects of heat flux, mass flux, and pressure on heat transfer were systematically analyzed. Seven heat transfer correlations based on tube data and three correlations derived from rod bundle data were evaluated with the experimental results. The findings reveal that the Jackson 1 correlation exhibits the highest agreement with the experimental data. Furthermore, two new correlations were developed based on the section-averaged wall temperature and section-maximum wall temperature, respectively. These newly proposed correlations not only enhance prediction accuracy but also increase their utility for practical applications.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"247 ","pages":"Article 127141"},"PeriodicalIF":5.0,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The formation mechanism and process regulation of collapse defects in high-power laser penetration welding of 20mm thick 316L stainless steel plates","authors":"Yiyang Hu ,&nbsp;Chunming Wang ,&nbsp;Zehui Liu ,&nbsp;Zhongshun Zhao ,&nbsp;Fei Yan","doi":"10.1016/j.ijheatmasstransfer.2025.127123","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127123","url":null,"abstract":"<div><div>Laser penetration welding provides significant efficiency advantages for single-pass joining of thick stainless steel plates. However, as plate thickness increases, the challenge of \"full penetration leads to collapse\" persists. This study successfully achieves single-pass welding formation of 20 mm thick steel plates, identifying the process bottleneck in high-power thick-plate laser full-penetration welding as the excessively large output laser spot size and addressing the welding challenges associated with thicker plates. A novel numerical model was employed to explore the mechanisms behind collapse defects. To quantitatively assess weld quality, the degrees of \"underfill\" and \"sagging\" were evaluated based on national standards, and various weld formations were categorized accordingly. The results indicated that welding with a large spot size of 937.5 μm rarely produced a well-formed weld. In contrast, using a smaller spot size of 600 μm created a partial process window, where the laser power threshold for \"full penetration leads to collapse\" decreased from 25,000 W to 20,000 W. High-speed imaging and numerical simulations further revealed two critical factors necessary for achieving high-quality weld formation. First, the mass of molten material lost as spatter and droplets must remain minimal. Second, a well-defined backflow channel must be established, ensuring the upward movement of molten material under the influence of the Marangoni effect. This study highlighted the crucial role of spot size in the laser penetration welding of thick plates and provides guidance for selecting optimal laser parameters. Additionally, it elucidated the underlying mechanisms of weld formation, offering theoretical insights for process regulation.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"247 ","pages":"Article 127123"},"PeriodicalIF":5.0,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859942","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":"Improving the Accuracy of Transient Plane Source Thermal Conductivity Measurements: Novel Analytical Models, Fitting Approaches, and Systematic Sensitivity Analysis","authors":"Jiaqi GU,&nbsp;Saad Bin SAFIULLAH,&nbsp;Yang LU,&nbsp;Ziyan QIAN,&nbsp;Qiye ZHENG","doi":"10.1016/j.ijheatmasstransfer.2025.127110","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127110","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Accurate thermal conductivity (&lt;em&gt;λ&lt;/em&gt;) measurement is critical for optimizing material performance in applications where effective heat exchange and dissipation are paramount. Among contact methods, the transient plane source (TPS) method (ISO 22007-2:2022) is widely used for its efficiency and versatility, particularly for bulk solid samples. However, we reveal that for high-&lt;em&gt;λ&lt;/em&gt; materials (&lt;em&gt;λ&lt;/em&gt; &gt; 30 W/(m·K)), TPS measurements can suffer from significant systematic errors—up to 97%—due to the limitations of traditional analytical models and fitting methods in addressing sensor/sample interface thermal resistance (&lt;em&gt;R&lt;sub&gt;c&lt;/sub&gt;&lt;/em&gt;) and heat conduction within the sensor. Furthermore, the lack of in-depth investigation into measurement sensitivity and parameter correlations in the TPS method hampers the accurate fitting and identification of sample &lt;em&gt;λ&lt;/em&gt;, particularly under the influence of other unknown parameters such as sample heat capacity (&lt;em&gt;C&lt;/em&gt;) and &lt;em&gt;R&lt;sub&gt;c&lt;/sub&gt;&lt;/em&gt;. This study addresses these challenges by: (1) developing two novel analytical models, termed realistic sensor model (RSM) and multilayer model (MLM), that account for heat transfer within the sensor and the &lt;em&gt;R&lt;/em&gt;&lt;sub&gt;c&lt;/sub&gt; effect, both of which are neglected in the traditional model but crucial in the TPS study of high-&lt;em&gt;λ&lt;/em&gt; materials; (2) proposing an innovative temperature derivative-based analysis approach using nonlinear regression (NR) to effectively suppress the influence of the &lt;em&gt;R&lt;/em&gt;&lt;sub&gt;c&lt;/sub&gt; and the sensor geometry, which outperforms the conventional iterative linear regression of the raw temperature data; and (3) systematically analyzing the sensitivities of key parameters in different analytical and numerical models as well as parameter relationships via singular value decomposition (SVD) of the sensitivity matrix, providing deeper insights into the selection of the optimal time interval for fitting sample &lt;em&gt;λ&lt;/em&gt; and &lt;em&gt;C&lt;/em&gt;.&lt;/div&gt;&lt;div&gt;To reveal the limitations of traditional models and regression while evaluating our new analytical models and fitting methods, a reliable 3D finite element model (FEM) that replicates the actual TPS sensor with bifillar spiral heater was developed . The TPS experiments on four representative materials with significantly varied &lt;em&gt;λ&lt;/em&gt; (polymethyl methacrylate, borosilicate glass, 304 stainless steel, and aluminum) and simulated TPS data for a broad range of materials (&lt;em&gt;λ&lt;/em&gt; in 0.1–400 W/(m·K)) from our FEM simulations are utilized to systematically assess the performance of the proposed analytical model and fitting methods. We demonstrate that the proposed derivative-based approach combined with the new analytical models using two-parameters NR (NR-2) exhibits high robustness against &lt;em&gt;R&lt;sub&gt;c&lt;/sub&gt;&lt;/em&gt; and improves the accuracy of the fitted &lt;em&gt;λ&lt;/em&gt;, reducing errors from 50-97% to &lt; 10% for high-&lt;em&gt;λ&lt;/em&gt; material, which remain robust against ","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"247 ","pages":"Article 127110"},"PeriodicalIF":5.0,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859940","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":"Investigating the relationship of process parameter, heat-mass transfer and joint strength in Mg/Al friction stir lap welding via experiments, machine learning and numerical analysis","authors":"Ming Zhai ,&nbsp;JiaLin Yin ,&nbsp;ChunLiang Yang ,&nbsp;ChuanSong Wu ,&nbsp;HongTu Song ,&nbsp;WenZhen Zhao ,&nbsp;Lei Shi ,&nbsp;JunNan Qiao","doi":"10.1016/j.ijheatmasstransfer.2025.127143","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127143","url":null,"abstract":"<div><div>With the increasing demand for lightweight structures, Mg/Al friction stir lap welding (FSLW) has attracted more attention. In this study, the relationship of process parameter, heat-mass transfer behaviors and joint strength is comprehensively investigated by the combination method of experimental tests, machine learning and numerical analysis. Contrary to the traditional understanding, the optimal joint strength appears at low rotation rate (600 rpm) and high welding speed (90 mm/min). The developed ensemble machine learning model (gradient boosting regression + gaussian process regression) quantitatively maps process parameter - joint strength relationship. The joint strength can be effectively improved by properly decreasing the rotation rate and increasing the welding speed within the process window. Numerical analysis reveals the heat and mass transfer mechanisms. Compared with the process parameter of 1000 rpm - 60 mm/min, when the process parameters is 600 rpm - 90 mm/min, the welding temperature decreases by about 35 K and the material flow velocity decreases by about 50 mm/s. It is helpful to form smaller hook, cold lap and thinner intermetallic compounds (IMCs), which is beneficial to improve the lap joint strength. The findings show that although the increase of rotation rate can enhance the mixing of materials, excessive rotation will aggravate the materials diffusion. The balance between mechanical interlocking and metallurgical bonding can be achieved by adopting appropriate combination of process parameters. This work can provide theoretical basis for the design principle of Mg/Al FSLW process.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"247 ","pages":"Article 127143"},"PeriodicalIF":5.0,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859938","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":"Electroosmotic slip flow in peristaltic transport of non-Newtonian third-grade MHD fluid: RSM-based sensitivity analysis","authors":"R. Ellahi ,&nbsp;A. Zeeshan ,&nbsp;Samar Shafique ,&nbsp;Sadiq M. Sait ,&nbsp;Amad ur Rehman","doi":"10.1016/j.ijheatmasstransfer.2025.127121","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127121","url":null,"abstract":"<div><div>An innovative model of electroosmotic peristaltic motion produced by a third-grade non-Newtonian magnetohydrodynamics fluid within a symmetric conduit is proposed. Three nonlinear coupled partial differential equations govern the flow problem are reduced to a system of nonlinear coupled ordinary differential equations by using the approximations of long wave length and low Reynolds number. Response Surface Methodology based Central Composite Design is utilized to predict refined empirical model. The adequacy of the fitted model is assessed using an analysis of variance. The influence of the Hartman number, Deborah number, and electroosmotic parameter on pressure rise per wavelength and frictional forces is prognosticated graphically. It is observed that the axial velocity increases by increasing the values of electroosmotic parameter, however, quite a reverse behaviour in axial velocity is noted for higher values of the Helmholtz-Smoluchowski parameter, slip parameter and Hartmann number. A sensitivity analysis of physical parameters is presented. It is reveals that the Deborah number has a substantial impact on pressure rise per wavelength and frictional forces in the electroosmotic flow system.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"247 ","pages":"Article 127121"},"PeriodicalIF":5.0,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855678","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":"Modeling of torque resistance in laminar annular rotating flow with axial flow","authors":"Guoqiang Xu ,&nbsp;Guanglong Zhao ,&nbsp;Tao Dong ,&nbsp;Yongkai Quan ,&nbsp;Jingchuan Sun ,&nbsp;Lina Zhang ,&nbsp;Laihe Zhuang ,&nbsp;Bensi Dong","doi":"10.1016/j.ijheatmasstransfer.2025.127119","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127119","url":null,"abstract":"<div><div>The issue of electric power shortage in hypersonic aircraft has become increasingly prominent in recent years. The liquid-cooling ram air turbine power generation system, which uses fuel as the cooling medium, offers an effective solution. However, the high viscosity of the liquid causes significant rotating resistance torque, which reduces the energy conversion efficiency of the system. Moreover, the accurate prediction of the rotating resistance of the annulus in generator is limited by the applicability of existing expressions. To study the rotating torque characteristic in the stator-rotor gap of the liquid-cooling generator, the fundamental flow model, namely laminar annular rotating flow with axial flow (LARAF), is investigated in this paper. By drawing an analogy to transient parallel plane Couette flow, a torque expression applicable to LARAF is derived. Numerical simulations are performed to study the flow behavior in detail. A correction expression as function of the axial Reynolds number is established through statistical analysis. The predicted torque values are consistent with experimental results, with deviations remaining within ±7 %. A simplified method for deriving the torque expression of LARAF is developed by analogy method and good prediction accuracy is achieved through correction. This study proposes a novel perspective for understanding the torque characteristics of LARAF, laying a theoretical foundation for future research on annular rotating flow with axial flow in the presence of vortices or turbulence.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"247 ","pages":"Article 127119"},"PeriodicalIF":5.0,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855677","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":"Analysis of UV radiation of solid rocket plume containing multiphase alumina clusters","authors":"Yueyuan Xu ,&nbsp;Lu Bai ,&nbsp;Ligong Zhang ,&nbsp;Jinlu Li ,&nbsp;Huigang shi ,&nbsp;Lixin Guo","doi":"10.1016/j.ijheatmasstransfer.2025.127125","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127125","url":null,"abstract":"<div><div>Alumina particles, ejected from rocket nozzles, undergo dynamic crystallization, resulting in multiphase clusters in the rocket plume. These multiphase alumina (MA) clusters exhibit significantly different optical properties compared to stable-phase alumina studied in previous research, inevitably affecting the radiative characteristics of the plume. However, research in this area remains sparse. To address this, a plume radiation model incorporating multiphase alumina was proposed to analyze the UV radiation characteristics of the solid rocket plume containing multiphase alumina clusters. The line-by-line integration method was used to solve the absorption coefficient of OH molecules, and super position T-matrix method and the statistical average optical algorithm were utilized to obtain the optical properties of alumina clusters. The results indicate that, if the presence of multiphase alumina clusters is ignored, the radiance of plumes will be underestimated by 41.3 % in our study. The thermal radiation and scattering of alumina clusters can increase the UV radiation of plume, and the magnitude of such enhancement is affected by the phase state of alumina. Although our study used simplified cluster models due to the lack of precise data for each alumina cluster in the plume, it emphasizes the importance of alumina’s phase state in plume radiation studies. The findings offer a new theoretical foundation for aircraft detection and identification.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"247 ","pages":"Article 127125"},"PeriodicalIF":5.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143851727","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":"Mesoscopic scale model for predicting thermal conductivity of aeolian sand-rock-layer mixed medium in cold regions","authors":"Fenglei Han ,&nbsp;Guo Li ,&nbsp;Lu Cheng ,&nbsp;Wenbing Yu ,&nbsp;Shenglin Wang","doi":"10.1016/j.ijheatmasstransfer.2025.127093","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127093","url":null,"abstract":"<div><div>The filling and accumulation of aeolian sand altered hydrothermal response of crushed-rock embankment (CRE) in the permafrost regions of the Qinghai-Tibet Plateau, significantly reducing its cooling capacity. Accurately determining the equivalent thermal conductivity of the mixed medium layer is the premise for evaluating the long-term thermal stability of CRE under aeolian sand conditions. Unlike traditional empirical thermophysical formulas, this paper established a mesoscopic scale model (ESE) to predict the equivalent thermal conductivity of the aeolian sand-rock-layer mixed medium, employing equivalent rules and mesoscopic three-phase theory. The ESE model was verified by laboratory experiments, demonstrating comparable accuracy to six other theoretical models. The errors of different prediction models and the main influencing factors were compared and analyzed. The results demonstrate that the predictions of the ESE model align well with experimental data. For moisture contents between 0.00 % and 15.00 %, the equivalent thermal conductivity ranges from 0.64 to 2.01 W·m⁻¹· °C⁻¹ in the frozen state (-5.00 °C) and from 0.64 to 1.61 W·m⁻¹· °C⁻¹ in the unfrozen state (5.00 °C). Among the six comparative theoretical models, the ESE model achieved the highest accuracy, with an average relative error of 5.70 %. The influence of each factor in the model ranked as follows: sand content (0.764) &gt; porosity (0.613) &gt; water content (0.598) &gt; temperature (0.447). The research results provide a theoretical basis for selecting thermophysical parameters to predict cooling performance of CRE in sandy environments.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"247 ","pages":"Article 127093"},"PeriodicalIF":5.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143851728","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":"Constructing a breakthrough pressure and blockage based PEMFC model for elucidating water and gas transport in gas diffusion layers","authors":"Guan Shumeng ,&nbsp;Zhou Fen ,&nbsp;Zhan Zhigang ,&nbsp;Pan Mu","doi":"10.1016/j.ijheatmasstransfer.2025.127122","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127122","url":null,"abstract":"<div><div>The performance of proton exchange membrane fuel cells (PEMFCs) is strongly relied on the transport of water and gas in a gas diffusion layer (GDL). In this study, it introduces a novel concept of water blockage as an alternative to the traditional definition of water saturation. Concurrently, breakthrough pressure drainage mechanism is proposed. Building on these concepts, it develops a new model for the water and gas transport elucidation. The breakthrough pressure is defined as the point at which the hydraulic pressure at the entrance of the pores exceeds a critical threshold, enabling liquid water to penetrate into the pores of MPLs. At the same time, it is considered that the pore area filled with water in MPLs cannot be transported by gas, and the ratio of this area to the total pore area of the cross section parallel to the surface of the MPL is defined as water blockage. The water blockage will be more conducive to evaluate the water and gas transport performance of MPLs than water saturation.</div><div>Based on the breakthrough pressure and water blockage, a new model of water and gas transport in PEMFCs is constructed. In-depth study on the water and gas transport process with the new model, it is found that: (1) The water blockage in the MPL increases with the increase of back pressure. It is showed that the increase of back pressure is a double-edged sword. In the low back pressure range, increasing the back pressure can increase oxygen partial pressure, contributing an enhanced exchange current density and cell performance. However, when the back pressure is high enough, the increased water blockage would reduce the gas transport path, resulting in a serious concentration polarization and a decline of the performance at high current density. (2) The water blockage is also strongly related to the pore size in MPLs. Macropores are more likely to be filled by water and used as liquid water transport channels, while pores with small size that are not easy to be blocked which is applied as gas transport paths. Therefore, the MPL with bimodal pore distribution is more conducive to achieving excellent water and gas transport performance. (3) On the premise of maintaining or improving the porosity of the MPL, increasing the proportion of small pores can significantly reduce the water blockage at high current density and enhance the cell performance.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"247 ","pages":"Article 127122"},"PeriodicalIF":5.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143851730","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}