International Journal of Heat and Mass Transfer最新文献_第5页

Film cooling performance and aerodynamic characteristics of mid-passage gap in turbine guide vane doublets 涡轮导叶双叶中间间隙气膜冷却性能及气动特性

IF 5 2区工程技术

International Journal of Heat and Mass Transfer Pub Date : 2025-07-23 DOI: 10.1016/j.ijheatmasstransfer.2025.127568

Yufan Wang , Weihao Zhang , Shuai Jing , Dongming Huang

{"title":"Film cooling performance and aerodynamic characteristics of mid-passage gap in turbine guide vane doublets","authors":"Yufan Wang , Weihao Zhang , Shuai Jing , Dongming Huang","doi":"10.1016/j.ijheatmasstransfer.2025.127568","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127568","url":null,"abstract":"<div><div>In engineering practice, high-pressure turbine guide vanes are generally manufactured as single- or double-airfoil sections, inevitably introducing mid-passage gaps (MPGs) between adjacent sections. Although doublet vanes can reduce leakage losses, there is little research analyzing their flow and cooling characteristics. This study numerically focuses on the differences in cooling and aerodynamic characteristics among gapless structures, singlets, and doublets. The results show that MPGs complicate the vortex system near the endwall of the passage, and doublets alter the characteristics of vortex interactions downstream of the trailing edge (TE). Gas ingress and radial leakage jets are the primary flow features introduced by MPGs. The gas ingress leads to an increase in the leakage rate and narrows the outflow area, resulting in an enhancement of the leakage. Leakage jets roll up into leakage vortex (LV) under cross-flow and also enhances upper passage vortex (UPV). Entrained into these vortices, the coolant effectively cools the endwall downstream of MPGs. The UPV adheres closely to the suction side of the passage, whereas the LV adheres to the pressure side. Consequently, in the region downstream of the TE, the LV interacts with the UPV from the adjacent passage rather than from the same passage. Therefore, the flow field downstream of the TE in doublets is not a simple alternating superposition of that from gapless structures and singlets. Instead, it develops distinct loss and cooling characteristics in doublets. Additionally, MPGs significantly enhance the wake, while doublets introduce new periodic characteristics to the outlet flow field.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"253 ","pages":"Article 127568"},"PeriodicalIF":5.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686044","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}

引用次数: 0

Evaluating the thermal effects of Gaussian versus rectangular laser beams on single-layer biological tissues: Implications for advanced biomedical therapies 评估高斯激光束与矩形激光束对单层生物组织的热效应：对先进生物医学治疗的意义

IF 5 2区工程技术

International Journal of Heat and Mass Transfer Pub Date : 2025-07-23 DOI: 10.1016/j.ijheatmasstransfer.2025.127569

Mohsan Hassan , Fateh Mebarek-Oudina , Edrisa Jawo , A.I. Ismail , M.M. Helal

{"title":"Evaluating the thermal effects of Gaussian versus rectangular laser beams on single-layer biological tissues: Implications for advanced biomedical therapies","authors":"Mohsan Hassan , Fateh Mebarek-Oudina , Edrisa Jawo , A.I. Ismail , M.M. Helal","doi":"10.1016/j.ijheatmasstransfer.2025.127569","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127569","url":null,"abstract":"<div><div>This study explores the thermal dynamics of single-layer biological tissues subjected to Gaussian and rectangular laser beams, focusing on their unique thermal characteristics and potential medical applications. A comprehensive mathematical model that incorporates the Local Thermal Non-equilibrium (LTNE) framework is utilized, considering factors like tissue porosity and dual-lag effects to better understand thermal behavior. Through extensive numerical simulations, the influences of porosity, laser intensity, and exposure duration on the tissues under both beam configurations are analyzed. Results reveal that rectangular beams produce intense, localized heating, resulting in sharp temperature peaks that are particularly advantageous for targeted therapies. In contrast, Gaussian beams facilitate more uniform temperature distributions, which are beneficial for treatments requiring broader thermal coverage. Notably, it is found that increased porosity significantly mitigates maximum temperatures and reduces the extent of thermal damage, whereas higher laser intensities and prolonged exposure times lead to heightened tissue temperatures and an increased risk of thermal injury. These findings enhance the current understanding of bio-heat transfer mechanics and offer valuable guidance for the design and implementation of safer and more effective laser-based therapeutic systems.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"253 ","pages":"Article 127569"},"PeriodicalIF":5.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686059","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}

引用次数: 0

Theoretical modeling of the stratified flow in a hybrid extraction ventilated room with a localized buoyancy source 局部浮力源混合抽提通风室内分层流动的理论建模

IF 5 2区工程技术

International Journal of Heat and Mass Transfer Pub Date : 2025-07-23 DOI: 10.1016/j.ijheatmasstransfer.2025.127530

H.N. Fauzi, Y.J.P. Lin

{"title":"Theoretical modeling of the stratified flow in a hybrid extraction ventilated room with a localized buoyancy source","authors":"H.N. Fauzi, Y.J.P. Lin","doi":"10.1016/j.ijheatmasstransfer.2025.127530","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127530","url":null,"abstract":"<div><div>This study develops a set of steady-state theoretical models for the indoor stratified flow driven by the combined effects of the buoyancy force by a localized heat source and the inertial force by an extraction device. The investigation considers an isolated room that has a vent and a mechanical extraction device at the ceiling level and a vent at the floor level. The combined effects of different mechanical extraction flow rates and a fixed buoyancy flux of a localized heat source on the stratified flow are investigated. In addition, various effective vent area ratios are considered as part of this study. Salt bath experiments are conducted in a reduced-scale building model to validate the theoretical models. The interface height and the reduced gravity of the buoyant layer observed in the experiments are in reasonable agreement with those predicted by the theoretical models. In this study, the volumetric flow rates through both the ceiling-level and floor-level openings were not directly measured by using this experimental technique, and the volumetric flow rates are estimated by using experimental data of the interface height and the reduced gravity instead. Two flow regimes are observed, the forward and reverse flow regimes separated by the critical flow rate, in the hybrid extraction ventilated space. In the forward flow regime, the interface height and the reduced gravity of the buoyant layer depend on the extraction flow rate and the effective vent area ratio. These variables still influence the interface height in the reverse flow regime, while the extraction flow rate alone determines the reduced gravity of the buoyant layer.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"253 ","pages":"Article 127530"},"PeriodicalIF":5.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686038","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}

引用次数: 0

Enhanced close-contact melting by tuning container configurations for fast-charging latent heat storage systems 通过调整用于快速充电潜热储存系统的容器配置来增强近接触熔化

IF 5 2区工程技术

International Journal of Heat and Mass Transfer Pub Date : 2025-07-23 DOI: 10.1016/j.ijheatmasstransfer.2025.127549

Jia-Jie Jiang , Li-Wu Fan

{"title":"Enhanced close-contact melting by tuning container configurations for fast-charging latent heat storage systems","authors":"Jia-Jie Jiang , Li-Wu Fan","doi":"10.1016/j.ijheatmasstransfer.2025.127549","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127549","url":null,"abstract":"<div><div>Latent heat energy storage (LHES) systems using energy-intensive phase change material (PCM) have gained increasing attention for solar thermal utilization and industrial waste heat recovery. Close-contact melting (CCM), which maintains a small gap between the unmelted PCM and the heated surface, is known to allow high-power LHES. For enclosed PCM containers, however, the contribution of CCM to the total charging process and its dependence on the container configurations remain unclear. In this work, the effects of CCM on the melting of a paraffin wax in rectangular containers with various geometrical and thermal configurations were studied numerically. The results showed that reducing the container height-to-width ratio from 6.25 to 0.25 improves the melting contribution of CCM from 38% to 87%, with a corresponding 65% reduction of the melting time. As the aspect ratio decreases, the gravity center of the unmelted PCM moves closer to the heated bottom surface, and the liquid film thickness slightly grows. In comparison to the top and side walls, heating from the bottom wall was demonstrated to be more efficient to facilitate CCM, which drastically shortens the melting time. When elevating the bottom wall superheat from 18 to 30°C, the melting fraction can be generalized using the dimensionless group FoSte<sup>0.9</sup>, and the maximum mean power density for LHES reaches 500 W/kg. These findings can serve as practical design guidelines for enhancing the CCM mechanism in a passive manner to realize fast-charging LHES systems.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"253 ","pages":"Article 127549"},"PeriodicalIF":5.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686040","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}

引用次数: 0

High Weber number fuel drop breakup during impact with heated walls 高韦伯数燃料在撞击加热壁时破裂

IF 5 2区工程技术

International Journal of Heat and Mass Transfer Pub Date : 2025-07-23 DOI: 10.1016/j.ijheatmasstransfer.2025.127532

Enzhe Song, Tian Yang, Lili Lu, Xuankun Liu, Chong Yao

{"title":"High Weber number fuel drop breakup during impact with heated walls","authors":"Enzhe Song, Tian Yang, Lili Lu, Xuankun Liu, Chong Yao","doi":"10.1016/j.ijheatmasstransfer.2025.127532","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127532","url":null,"abstract":"<div><div>Understanding high Weber number fuel drop breakup during impact with walls is critical to the prediction and optimization of fuel-air mixture distribution in internal combustion engines. In combustors, drops impact walls over a range of wall temperatures and drop velocities, resulting in complex outcomes. In this paper, diesel and methanol drops were tested under wall temperatures ranging from 27 to 400 °C with Weber numbers extending up to 2000. The drop impact events were recorded using high-speed imaging, allowing the identification of impact outcomes and analysis of secondary droplets. Initially, the basic dynamic behaviors of drops impacting on the wall at high Weber numbers were discussed, including the edge splashing that occurred at the initial moment and the subsequent phase-change characteristics. The results show that the effect of wall temperature on the critical Weber number for splashing differs between the two types of fuel. As the wall temperature rises, four heat transfer phenomena are observed: film evaporation, nucleate boiling, transition boiling, and film boiling. Subsequently, the disintegration behavior of drops impacting walls above the fuel’s dynamic Leidenfrost temperature was investigated, with statistical analyses of both impact residence time and the normalized Sauter mean diameter of secondary droplets. The mechanism of liquid film levitation and its disintegration into secondary droplets depend on the vaporization of the wetted area of the spreading liquid film. This article enhances the understanding of drop impact dynamics on heated surfaces, which can provide a theoretical basis and data support for the development of methanol/diesel dual-fuel direct injection engines.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"253 ","pages":"Article 127532"},"PeriodicalIF":5.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686041","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}

引用次数: 0

Generalized dual-phase-lag modeling of rectal wall thermal protection in prostate laser therapy using hyaluronic acid, collagen, and balloon spacers 使用透明质酸、胶原蛋白和球囊间隔剂的前列腺激光治疗中直肠壁热保护的广义双相位滞后模型

IF 5 2区工程技术

International Journal of Heat and Mass Transfer Pub Date : 2025-07-23 DOI: 10.1016/j.ijheatmasstransfer.2025.127570

Phanuwat Boontatao , Nattadon Pannucharoenwong , Piyawat Sermlao , Suphasit Panvichien

{"title":"Generalized dual-phase-lag modeling of rectal wall thermal protection in prostate laser therapy using hyaluronic acid, collagen, and balloon spacers","authors":"Phanuwat Boontatao , Nattadon Pannucharoenwong , Piyawat Sermlao , Suphasit Panvichien","doi":"10.1016/j.ijheatmasstransfer.2025.127570","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127570","url":null,"abstract":"<div><div>Prostate laser therapy is a widely accepted minimally invasive procedure due to its precision and effective treatment outcomes. However, increasing laser energy to improve therapeutic efficacy can result in excessive thermal exposure to adjacent healthy tissues, particularly the rectum. This raises concerns about rectal toxicity, primarily due to the anatomical proximity of the prostate to the anterior rectal wall. This study numerically investigated the influence of prostate-rectum separation distance and different interstitial spacers, namely Hyaluronic Acid (HA), Collagen, and Balloon Spacers on reducing rectal wall thermal exposure during prostate laser therapy. The simulations were performed using the Generalized Dual-Phase-Lag (GDPL) bioheat transfer model to predict transient temperature distributions in biological tissues. Spacer-induced separation distances of 4.0, 5.1, 7.1, and 8.8 mm were analyzed. The results demonstrated that all spacer materials significantly reduced the peak rectal wall temperature compared to the no spacer condition. Temperature reductions of 53.56 %, 54.81 % and 55.34 % were observed for Collagen, Balloon Spacers and Hyaluronic Acid, respectively. Furthermore, increasing the spacer thickness resulted in additional temperature reductions, with Hyaluronic Acid providing the greatest thermal protection across all distances. These findings suggest that the use of interstitial spacers can effectively mitigate unintended thermal damage to the rectal wall during prostate laser therapy. Among the materials evaluated, Hyaluronic Acid showed superior thermal insulation performance. These results provide valuable insights for improving thermal safety in prostate cancer laser treatments and support future clinical validation.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"253 ","pages":"Article 127570"},"PeriodicalIF":5.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686058","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}

引用次数: 0

Thermal characteristics analysis of a novel vapor chamber suitable for air-cooled PEMFC thermal management 适用于空冷式PEMFC热管理的新型蒸汽室热特性分析

IF 5 2区工程技术

International Journal of Heat and Mass Transfer Pub Date : 2025-07-23 DOI: 10.1016/j.ijheatmasstransfer.2025.127575

Jing Zhao , Xinxuan Cheng , Zixun Zhong , Yongkang Ma , Caiting Zhou , Youfu Lv , Baoshan Xie , Zhenxin Yi , Chuanchang Li

{"title":"Thermal characteristics analysis of a novel vapor chamber suitable for air-cooled PEMFC thermal management","authors":"Jing Zhao , Xinxuan Cheng , Zixun Zhong , Yongkang Ma , Caiting Zhou , Youfu Lv , Baoshan Xie , Zhenxin Yi , Chuanchang Li","doi":"10.1016/j.ijheatmasstransfer.2025.127575","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127575","url":null,"abstract":"<div><div>PEMFCs generate substantial waste heat during operation, which can degrade performance and durability if not promptly dissipated. Effective thermal management is therefore crucial for the efficient operation of PEMFCs. In this study, a novel vapor chamber designed specifically for integration with air-cooled PEMFCs was proposed, offering superior thermal management through direct sandwiching between flow field plates. The vapor chamber features an innovative support column structure with etched cross-shaped micro-grooves, enhancing capillary-driven working fluid transport and mechanical robustness under stack clamping. The influence of key factors such as heat load, gravity, and cooling conditions on the thermal characteristics of vapor chambers was investigated. The experimental results indicated that the VC could remove 35–40 W of heat and achieve thermal equilibrium within 100 s. The comparison with the copper plate further proved that the vapor chamber had excellent temperature equalization ability and thermal diffusion rate. Besides, this study revealed that gravity and cooling conditions had a significant effect on the thermal characteristics of the vapor chamber. When the tilt angle was 90°, the overall temperature difference and thermal resistance of the vapor chamber were minimal. Moreover, comparative experiments with simulated short stacks showed that, compared with air cooling, the VC-cooled system reduced the maximum temperature by 11 °C and the maximum temperature difference by 9 °C at a heat load of 25 W, highlighting its superior cooling efficiency and thermal uniformity in practical stack applications. The research results show that the vapor chamber meets the key thermal management requirements of PEMFCs and has great application potential in low and medium-power PEMFCs.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"253 ","pages":"Article 127575"},"PeriodicalIF":5.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686042","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}

引用次数: 0

Hybrid nongray radiation solver for combustion environments based on the full spectrum correlated k-distribution method 基于全谱相关k分布法的燃烧环境混合非灰色辐射求解器

IF 5 2区工程技术

International Journal of Heat and Mass Transfer Pub Date : 2025-07-23 DOI: 10.1016/j.ijheatmasstransfer.2025.127572

Nehal Jajal, Sandip Mazumder

{"title":"Hybrid nongray radiation solver for combustion environments based on the full spectrum correlated k-distribution method","authors":"Nehal Jajal, Sandip Mazumder","doi":"10.1016/j.ijheatmasstransfer.2025.127572","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127572","url":null,"abstract":"<div><div>Modeling thermal radiation in combustion environments is rendered challenging due to the extreme oscillatory nature of the absorption coefficient of most combustion gases. The radiative transfer equation (RTE) must be solved repeatedly to account for this nongray nature of gases. Two popular deterministic RTE solvers are the lowest order spherical harmonics approximation (P<sub>1</sub>) and the Finite Angle Method (FAM). The P<sub>1</sub> approximation results in a single elliptic partial differential equation making it efficient to solve, but it is only accurate for nearly isotropic intensity fields, typical of optically thick media. FAM can provide accurate solutions for all optical thicknesses, but requires sufficient angular resolution, which can become increasingly computationally expensive. Here, a Hybrid RTE solver, used in conjunction with the full-spectrum correlated <em>k</em>-distribution (FSCK) nongray model, is proposed and assessed. The solver is <em>Hybrid</em> in the sense that it adaptively switches between P<sub>1</sub> and FAM based on the optical thickness of each FSCK quadrature point—the goal being to reduce the computational cost without sacrificing accuracy. The Hybrid solver is implemented within the OpenFOAM framework. It is first verified and optimized for the Sandia D x 4 turbulent jet flame in 2D with prescribed temperature and concentration fields (frozen field) and finally, its optimal version is used to compute the same flame in 3D with full two-way coupling (with the reacting flow solver) using reaction mechanisms of different levels of complexity. The Hybrid solver is found to predict the temperature distribution with comparable accuracy as FAM but with a speedup of 1.6x – 3x. Trade-offs between efficiency and accuracy are discussed.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"253 ","pages":"Article 127572"},"PeriodicalIF":5.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686049","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}

引用次数: 0

Hairpin vortex suppression and cooling enhancement in turbine blade trailing edges: A DDES study of bio-inspired ribs with streamwise length gradients 涡轮叶片尾缘的发夹涡抑制和冷却增强：具有流向长度梯度的仿生肋的DDES研究

IF 5 2区工程技术

International Journal of Heat and Mass Transfer Pub Date : 2025-07-23 DOI: 10.1016/j.ijheatmasstransfer.2025.127548

Yaping Sun , Qilong Liu , Shijie Li , Shaohua Han , Tianyi Huo , Runsheng Zhang , Leping Zhou , Li Li , Hui Zhang , Xiaoze Du

{"title":"Hairpin vortex suppression and cooling enhancement in turbine blade trailing edges: A DDES study of bio-inspired ribs with streamwise length gradients","authors":"Yaping Sun , Qilong Liu , Shijie Li , Shaohua Han , Tianyi Huo , Runsheng Zhang , Leping Zhou , Li Li , Hui Zhang , Xiaoze Du","doi":"10.1016/j.ijheatmasstransfer.2025.127548","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127548","url":null,"abstract":"<div><div>To address the escalating thermal challenges in gas turbine blade Trailing Edges (TEs), this study introduces a novel bio-inspired rib cooling architecture, inspired by shark dermal denticles, to synergistically enhance film cooling effectiveness while suppressing adverse pressure losses. Leveraging the Delayed Detached-Eddy Simulation (DDES) method, the unsteady vortex dynamics and thermal performance of three TE configurations are systematically investigated: conventional pin fins (Case 1) and bio-inspired ribs with distinct streamwise length variations (Δ<em>l</em>/<em>L</em><sub>0</sub> = 1/6 for Case 2; 1/3 for Case 3) at blowing ratios <em>M</em> = 0.50 and 1.25. Key findings reveal that the bio-inspired ribs, particularly Case 3, outperform conventional designs by 46 % in laterally averaged cooling effectiveness (<em>η</em>) at <em>M</em> = 0.50 through targeted vortex modulation - suppressing large-scale hairpin vortices and redirecting transverse secondary flows to homogenize coolant coverage. However, at <em>M</em> = 1.25, excessive coolant-mainstream mixing under high momentum conditions reduces <em>η</em> by 33 % for Case 2, highlighting a critical trade-off between vortex control efficacy and blowing ratio. Mechanistically, the rib length variation governs boundary layer reattachment and fragmented vortex generation, as quantified by <em>Q</em>-criterion and spectral analyses. This work pioneers a bionic design paradigm for extreme-condition thermal management, demonstrating that strategically tuned rib geometries can decouple turbulence enhancement from pressure penalty - a breakthrough for next-generation turbine cooling systems.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"253 ","pages":"Article 127548"},"PeriodicalIF":5.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686060","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}

引用次数: 0

Experimental certificate of secondary flow inhibits the crystallization fouling of CaCO3 in tube with twisted tape insert 二次流抑制CaCO3在扭曲带插入管内结晶结垢的实验证明

IF 5 2区工程技术

International Journal of Heat and Mass Transfer Pub Date : 2025-07-22 DOI: 10.1016/j.ijheatmasstransfer.2025.127550

Caiping Liu , Liangbi Wang , Liangchen Wang

{"title":"Experimental certificate of secondary flow inhibits the crystallization fouling of CaCO3 in tube with twisted tape insert","authors":"Caiping Liu , Liangbi Wang , Liangchen Wang","doi":"10.1016/j.ijheatmasstransfer.2025.127550","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127550","url":null,"abstract":"<div><div>Secondary flow is commonly used to enhance heat transfer of heat exchangers. Circulating water, being a commonly working fluid in heat exchangers, inevitably contains minerals that could form fouling, which deteriorates the heat transfer performance of the surface. But there are limited reports on the role of secondary flow in the crystallization fouling. This paper reports the role of secondary flow on the growth characteristics of CaCO<sub>3</sub> fouling. A number of experiments have been carried out to investigate the fouling process of calcium carbonate in an aluminum alloy tube with various twisted tape inserts, which produce secondary flow in different intensity. The experimental results reveal that secondary flow can inhibit fouling of CaCO<sub>3</sub>. The ability of inhibiting depends on the intensity of secondary flow that is indicated by a non dimensional parameter <em>Sw</em>. As <em>Sw</em> increases from 0 to 1896, the fouling thickness <em>δ</em><sub>c</sub> decreases from 1.4 × 10<sup>–4</sup> m to 3.49 × 10<sup>–5</sup> m, representing a reduction of nearly fourfold. Simultaneously, the mean growth rate of fouling crystal d<em>δ</em><sub>c</sub>/d<em>t</em> declines from approximately 1.69 × 10<sup>–10</sup> m/s to 2.69 × 10<sup>–11</sup> m/s, indicating a decrease of about sixfold. Secondary flow reduces global fouling resistance, thins the fouling thickness in progressive equilibrium state, and slows down the mean growth rate of fouling crystal. Notably, velocity and concentration of circulating water does not alter the inhibiting role of secondary flow.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"253 ","pages":"Article 127550"},"PeriodicalIF":5.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679724","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}

引用次数: 0