International Journal of Heat and Mass Transfer最新文献

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Enhancement of the film cooling performance by the combination of droplet/air coolant and upstream micro-vortex generator 结合液滴/空气冷却剂和上游微涡流发生器提高薄膜冷却性能
IF 5 2区 工程技术
International Journal of Heat and Mass Transfer Pub Date : 2024-10-29 DOI: 10.1016/j.ijheatmasstransfer.2024.126376
Wei Tian , Kuan Zheng , Zhiyun Hu , Na Cao
{"title":"Enhancement of the film cooling performance by the combination of droplet/air coolant and upstream micro-vortex generator","authors":"Wei Tian ,&nbsp;Kuan Zheng ,&nbsp;Zhiyun Hu ,&nbsp;Na Cao","doi":"10.1016/j.ijheatmasstransfer.2024.126376","DOIUrl":"10.1016/j.ijheatmasstransfer.2024.126376","url":null,"abstract":"<div><div>In this study, a combination of Euler-Lagrange method is adopted to investigate the effect of upstream micro-vortex generator (VG) on the film cooling performance of two-phase droplet/air film cooling. The droplet trajectories and flow field are also simulated to reveal the flow mechanism related to the improvement effect of micro-VG on the droplet/air film cooling performance. The results indicate that the anti-counter-rotating vortex pair (anti-CRVP) induced by micro-VG can expand the spreading region of droplets in spanwise direction, and also force the droplets to approach the wall, delaying the separation of droplets from the wall under high blowing ratios. As a result, the micro VG can effectively enhance the improvement effect of droplets on film cooling effectiveness in both spanwise and streamwise directions, thereby enhancing the overall cooling performance of droplet/air film cooling. In addition, the size and flow rate of droplets are also investigated to reveal the influence of droplet parameters on the performance of droplet/air film cooling. It was found that there is an optimal droplet size for the enhancement of droplet/air film cooling efficiency.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":"Article 126376"},"PeriodicalIF":5.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538320","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
A bulk nucleation model for flashing applications 闪光应用中的体核模型
IF 5 2区 工程技术
International Journal of Heat and Mass Transfer Pub Date : 2024-10-29 DOI: 10.1016/j.ijheatmasstransfer.2024.126244
Stanley John, Carlos F. Lange
{"title":"A bulk nucleation model for flashing applications","authors":"Stanley John,&nbsp;Carlos F. Lange","doi":"10.1016/j.ijheatmasstransfer.2024.126244","DOIUrl":"10.1016/j.ijheatmasstransfer.2024.126244","url":null,"abstract":"<div><div>Modeling flash evaporation cases is challenging due to their occurrence in high temperatures and mass flow rates, along with mass transfer taking place in a narrow region of space. As an improvement to the previous Limited Evaporation model, which was based on the normalized critical work of nucleation, a new Bulk Nucleation model based on Classical Nucleation theory is developed and tested in comparison with liquid–vapor evaporation experiments conducted at the Brookhaven National Laboratories. The original theory is modified to take into account the cluster size formed during nucleation and a minimum threshold of vapor volume fraction required to trigger large-scale mass transfer. The Bulk Nucleation model shows better predictions for radial volume fractions, representing an improvement over well-correlated predictions for area-averaged pressure and volume fractions. The discrepancy in the radial volume fractions is attributed to the presence of pressure taps used in experiments, which protrude into the fluid domain. The role of model parameters such as cluster size and vapor volume fractions in the mass transfer model is also discussed in detail in this study. Similar to previous work, the new model is implemented in the open-source Computational Fluid Dynamics solver OpenFOAM in an Euler–Euler framework, which provides for the use of inter-momentum forces such as lift, drag, and turbulent dispersion, which are essential for accurate predictions for transport and generation of new vapor bubbles.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":"Article 126244"},"PeriodicalIF":5.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538323","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}
引用次数: 0
Melting and solidification performance of latent heat thermal energy storage system under flip condition 翻转条件下潜热蓄热系统的熔化和凝固性能
IF 5 2区 工程技术
International Journal of Heat and Mass Transfer Pub Date : 2024-10-29 DOI: 10.1016/j.ijheatmasstransfer.2024.126370
Xueqiang Li , Qihui Wang , Xinyu Huang , Xiaohu Yang , Bengt Sundén
{"title":"Melting and solidification performance of latent heat thermal energy storage system under flip condition","authors":"Xueqiang Li ,&nbsp;Qihui Wang ,&nbsp;Xinyu Huang ,&nbsp;Xiaohu Yang ,&nbsp;Bengt Sundén","doi":"10.1016/j.ijheatmasstransfer.2024.126370","DOIUrl":"10.1016/j.ijheatmasstransfer.2024.126370","url":null,"abstract":"<div><div>Latent heat storage technology has made significant contributions to solving the problem of unstable renewable energy supply. Related research indicates that phase change devices are essential for the stability of spacecraft temperature control systems. However, phase change material (PCM) has low thermal conductivity, which reduces device thermal storage and release efficiency. Moreover, the PCM heat transfer performance is further affected by movements such as attitude adjustment during the launch and operation of spacecraft. This paper adopted active heat transfer enhancement technology to enhance uniformity and rate of heat transfer in latent heat thermal energy storage (LHTES) unit. A new method is presented on flipping LHTES unit at appropriate stages of the phase change process, namely flipping enhancement technology. This method effectively uses the benefits of natural convection to enhance heat transfer, reducing the storage and release time of LHTES systems. A physical model was established building upon verification with data in literature, and the effect of flipping under different phase transition fractions on melting and solidification performance within the square cavity was discussed through numerical simulation. Further analysis was conducted on factors including phase transition fraction, phase interface, temperature interface distribution, velocity interface distribution, and heat storage capacity. Finally, the response surface methodology (RSM) was adopted to analyze and determine the optimal flipping phase transition fraction. The research results indicate that flipping improves the heat transfer efficiency of LHTES. Flipping significantly enhances heat transfer 3–5 times during melting compared to solidification process. As the phase transition fraction increases, the complete melting/solidification time demonstrates a trend of decline followed by an increase. Through single factor analysis, the optimal flipping liquid fraction is 51.65 % during the melting process, leading to a substantial decrease in complete melting time by 25.71 %. Based on this, the optimal phase transition fraction combination of melting first and then solidification was explored, which shortened the melting-solidification full cycle time by 12.96 %. This study investigates the melting/solidification performance of LHTES unit under flip conditions, which guides the design of phase change thermal control devices and contributes to the field of spacecraft thermal management.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":"Article 126370"},"PeriodicalIF":5.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538322","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
The synergistic effect of honeycomb structure and substrate thermal conductivity on the reduction of contact time at high temperatures 蜂窝结构和基底导热性对缩短高温接触时间的协同效应
IF 5 2区 工程技术
International Journal of Heat and Mass Transfer Pub Date : 2024-10-29 DOI: 10.1016/j.ijheatmasstransfer.2024.126357
Minjie Liu, Shuaiquan Zhu, Zhili Ma, Gan Tian, Xiaoyu Ding
{"title":"The synergistic effect of honeycomb structure and substrate thermal conductivity on the reduction of contact time at high temperatures","authors":"Minjie Liu,&nbsp;Shuaiquan Zhu,&nbsp;Zhili Ma,&nbsp;Gan Tian,&nbsp;Xiaoyu Ding","doi":"10.1016/j.ijheatmasstransfer.2024.126357","DOIUrl":"10.1016/j.ijheatmasstransfer.2024.126357","url":null,"abstract":"<div><div>Rapid detachment of droplets at different temperatures has been extensively studied in recent years by regulating surface wettability or introducing well-designed topological structures. It is of practical significance in many industrial fields such as dropwise condensation, self-cleaning, and so on. However, a single material cannot satisfy a wide range of applications. The synergistic effect of surface structure and substrate thermal conductivity on the regulation of contact time at high temperatures has not been revealed. In this work, we prepare hierarchically non-interconnected honeycomb surfaces with four different substrates and explore droplet dynamics at different temperatures. The unique pancake bouncing can be observed on the honeycomb surface and the solid-liquid contact time is largely shortened, which is aroused by the generation of strong vapor pressure in the non-interconnected structure. We also discover that both the increase in temperature and substrate thermal conductivity can reduce the contact time of droplets on the honeycomb surface. Therefore, we speculate that droplet dynamics at high temperatures can be modulated through the rational use of substrate materials and topological structure, which may find wide applications in thermal-related fields, such as high-frequency spray cooling.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":"Article 126357"},"PeriodicalIF":5.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538364","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
Boiling enhancement on the thermally induced deformation surfaces 热诱导变形表面的沸腾增强
IF 5 2区 工程技术
International Journal of Heat and Mass Transfer Pub Date : 2024-10-29 DOI: 10.1016/j.ijheatmasstransfer.2024.126358
Yibo Yan , Weijia Zheng , Ling Xie , Changxiang Fan , Yanxin Hu , Tingting Wu
{"title":"Boiling enhancement on the thermally induced deformation surfaces","authors":"Yibo Yan ,&nbsp;Weijia Zheng ,&nbsp;Ling Xie ,&nbsp;Changxiang Fan ,&nbsp;Yanxin Hu ,&nbsp;Tingting Wu","doi":"10.1016/j.ijheatmasstransfer.2024.126358","DOIUrl":"10.1016/j.ijheatmasstransfer.2024.126358","url":null,"abstract":"<div><div>Enhancing boiling heat transfer by adding microstructures to boiling surfaces is an effective and simple method. However, traditional heat transfer surfaces cannot change their geometric structure after processing and forming and can only have good heat transfer characteristics under certain heat transfer conditions. Shape memory alloys exhibit a wide range of transformation temperatures and superior mechanical properties, which are expected to achieve adaptively enhanced heat transfer. In this study, the pool boiling heat transfer performance of surfaces with different structures made of shape memory alloys using HFE-7100 as the working fluid has been studied. The experimental results indicate that the curved microstructures have more activated nucleation sites, which are conducive to bubble generation in the early stage of boiling but prevent bubble detachment and liquid replenishment in the later stage of boiling. In contrast, the onset of nucleate boiling (ONB) of the upright microstructures appears later, and there is \"boiling retardation\", but it has higher heat transfer coefficients (HTCs) and the critical heat flux (CHF) in the later stage of boiling. However, the deformable microstructures surface (DMS) can adaptively adjust its microstructures to meet the heat transfer requirements at different boiling stages. Consequently, the DMS has the highest CHF and HTC, with maximum improvements of 98.58 % and 104.88 % compared to the polished surface (PS), respectively.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":""},"PeriodicalIF":5.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529957","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 and numerical analysis of the pressure drop and convective heat transfer in the three-period spirally fluted tubes 三周期螺旋凹槽管内压降和对流传热的实验与数值分析
IF 5 2区 工程技术
International Journal of Heat and Mass Transfer Pub Date : 2024-10-29 DOI: 10.1016/j.ijheatmasstransfer.2024.126267
Young Ha Jeon, Hie Chan Kang
{"title":"Experimental and numerical analysis of the pressure drop and convective heat transfer in the three-period spirally fluted tubes","authors":"Young Ha Jeon,&nbsp;Hie Chan Kang","doi":"10.1016/j.ijheatmasstransfer.2024.126267","DOIUrl":"10.1016/j.ijheatmasstransfer.2024.126267","url":null,"abstract":"<div><div>This study proposes a unique configuration for a three-period spirally fluted (3PSF) tube that strengthens the flow mixing effect to enhance heat transfer. Conventional spirally fluted tubes exhibit an internal flow with two periodic characteristics that depend on the number of starts and the spiral angle, while the proposed 3PSF tube also periodically varies the depth of the spiral dimple. Experimental and numerical analyses were carried out to investigate the heat transfer and flow characteristics of six types of 3PSF tube, which were compared to a circular tube and a conventional two-period spirally fluted tube. The heat transfer performance of the 3PSF tubes was determined based on the f-factor, Nusselt number, goodness factor, and performance evaluation criteria. For Reynolds numbers from 1,000 to 30,000, the 3PSF tube with three dimple periods per spiral lead had an f-factor and a Nusselt number that were 349–460% and 184–215%, respectively, of that of the two-period spirally fluted (2PSF) tube with the same outermost diameter. The performance evaluation criteria of 3PSF tubes are higher than that of 2PSF tube in the wide range of Reynolds number. In the 3PSF tubes, high velocity swirling strength developed along the main flow direction due to the varying depth of the spiral dimples. Consequently, the flow-mixing effects were enhanced, improving the heat transfer characteristics despite the higher pressure drop. The proposed 3PSF tube design thus demonstrates the potential to be employed in heat exchangers that require a high heat transfer.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":"Article 126267"},"PeriodicalIF":5.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538318","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-dynamic performance enhancement analysis on central impinging jet double layer microchannel heat sinks with variable working flow conditions verified by SLM 3D printing technology for the powerful electronics cooling system 利用 SLM 3D 打印技术验证强力电子设备冷却系统工作流条件可变的中央冲击射流双层微通道散热器的热动力性能提升分析
IF 5 2区 工程技术
International Journal of Heat and Mass Transfer Pub Date : 2024-10-29 DOI: 10.1016/j.ijheatmasstransfer.2024.126381
Xinyue Lan , Peng Li , Chi-Chuan Wang , Han Shen
{"title":"Thermal-dynamic performance enhancement analysis on central impinging jet double layer microchannel heat sinks with variable working flow conditions verified by SLM 3D printing technology for the powerful electronics cooling system","authors":"Xinyue Lan ,&nbsp;Peng Li ,&nbsp;Chi-Chuan Wang ,&nbsp;Han Shen","doi":"10.1016/j.ijheatmasstransfer.2024.126381","DOIUrl":"10.1016/j.ijheatmasstransfer.2024.126381","url":null,"abstract":"<div><div>In order to further improve the thermal performance of parallel straight double-layer microchannel heat sinks, the central impinging jet double layer microchannel heat sinks are designed. Six kinds of working flow conditions are examined in the designed structure, the designs feature two inlets and three outlets. Simulations were conducted for all configurations and the corresponding experimental samples made by selective laser melting (SLM) 3D are conducted for verification of the numerical simulations. It is found that the test results for heat transfer performance and pressure drop penalty are in line with the numerical results. Through combining the advantages of impinging jets and double layer structures, the controlling of peak temperature and thermal uniformity on substrate is quite effective. In comparison with parallel straight double-layer microchannel heat sinks, the maximum temperature on substrate in the central impinging jet double layer microchannel heat sinks with optimal working condition decreases significantly. As <em>Re</em> = 580, the Nusselt number of the optimal working conditions reaches 38.18, which increases by 51.86 % compared with the referenced model. Taking the overall thermal performance factor ((Nu/Nu<sub>0</sub>)/(Δp/Δp<sub>0</sub>)<sup>1/3</sup>) as the criterion to evaluate the comprehensive overall thermal performance, the optimal working condition has the value mentioned above up to 1.47 and the thermal resistance is at a very low level. It is worth mentioning that the pressure drop is not significantly increased under various working conditions.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":"Article 126381"},"PeriodicalIF":5.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538319","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
Homogenization-based analysis of pyrolysis and mechanical degradation of ablative silica fiber-reinforced phenolic resin composites 基于均质化的烧蚀硅纤维增强酚醛树脂复合材料热解和机械降解分析
IF 5 2区 工程技术
International Journal of Heat and Mass Transfer Pub Date : 2024-10-29 DOI: 10.1016/j.ijheatmasstransfer.2024.126328
Shuo Cao , Ting Fu , Ran Tao , Yiqi Mao , Shujuan Hou
{"title":"Homogenization-based analysis of pyrolysis and mechanical degradation of ablative silica fiber-reinforced phenolic resin composites","authors":"Shuo Cao ,&nbsp;Ting Fu ,&nbsp;Ran Tao ,&nbsp;Yiqi Mao ,&nbsp;Shujuan Hou","doi":"10.1016/j.ijheatmasstransfer.2024.126328","DOIUrl":"10.1016/j.ijheatmasstransfer.2024.126328","url":null,"abstract":"<div><div>Silica fiber-reinforced phenolic resin composites (SiFPRCs), characterized by exceptional insulative properties and ablation resistance, are widely utilized in thermal protection systems (TPS) and structural materials for hypersonic vehicles. Under extreme thermal conditions, the physicochemical ablative processes, including severe local thermal conduction, decomposition, and structural failure, lead to complex variations in thermomechanical properties. This study developed a homogenization-based thermomechanical model to investigate the micro-ablation characteristics of SiFPRCs and the resultant overall mechanical degradation. The ablation rate and porosity evolution were experimentally analyzed firstly, through oxyacetylene ablation experiments and mechanical property tests coupled with high-precision CT technology. Within the framework of non-equilibrium dissipative thermodynamics, a cross-scale consistent thermomechanical model integrating heat conduction and pyrolysis reaction characteristics of SiFPRCs was developed and implemented through a nonlinear finite element algorithm. After calibration and validation through comparison with experimental results, the developed model was applied to examine multiple thermal dissipation mechanisms, including thermal decomposition of phenolic resin, heat blocking effects, phase transitions in silica fibers, carbo-silicon reactions, and mechanical degradation. This research provides robust theoretical support and a design foundation for the development and application of high-performance TPS materials.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":"Article 126328"},"PeriodicalIF":5.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538274","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
Flow boiling in a relatively large copper heat sink comprised of Tesla microchannels 由特斯拉微通道组成的相对较大的铜制散热器中的流动沸腾
IF 5 2区 工程技术
International Journal of Heat and Mass Transfer Pub Date : 2024-10-29 DOI: 10.1016/j.ijheatmasstransfer.2024.126366
Zhaoxuan Liu , Qun Han , Jingwei Han , Yuanle Zhang , Xuemei Chen , Wenming Li
{"title":"Flow boiling in a relatively large copper heat sink comprised of Tesla microchannels","authors":"Zhaoxuan Liu ,&nbsp;Qun Han ,&nbsp;Jingwei Han ,&nbsp;Yuanle Zhang ,&nbsp;Xuemei Chen ,&nbsp;Wenming Li","doi":"10.1016/j.ijheatmasstransfer.2024.126366","DOIUrl":"10.1016/j.ijheatmasstransfer.2024.126366","url":null,"abstract":"<div><div>Flow boiling in copper microchannel heat sink is widely used for the cooling of high power electronic modules, particularly the IGBT power electronic modules with large sizes. However, it is challenging to significantly enhance the flow boiling performance of copper microchannel heat sink due to the long-lasting issue of vapor backflow and liquid supply that severely deteriorates flow boiling heat transfer. Also, a high channel length to hydraulic diameter ratio (L/D<sub>h</sub>) of a large heat sink is not favorable for efficient two-phase transport, resulting in the early occurrence of boiling crisis. In this work, a relatively large copper heat sink (<em>L</em> × <em>W</em> = 10 cm × 5 cm) comprised of Tesla microchannels characterized with excellent flow diodicity was designed and fabricated. The L/D<sub>h</sub> ratio of the as-designed heat sink is about 220, which is much larger than the reported studies. In this new heat sink, the periodic Tesla valve structures in each channel is capable of inhibiting the severe vapor backflow to dramatically enhance the two-phase transport and then delay the dryout of heating surface. To demonstrate the advantages of our design, the flow boiling performances in terms of heat transfer coefficient (HTC), critical heat flux (CHF), and two-phase flow stabilities were experimentally studied and a comprehensive comparison against a heat sink consisted of plain-wall microchannels is presented. Experiments were conducted on DI-water with total inlet flow rate varying from 20 ml·min<sup>-1</sup> to 50 ml·min<sup>-1</sup>. The results of this study show that flow boiling performances and two-phase flow stabilities are significantly enhanced owing to the successful suppression of two-phase backflow and efficient two-phase transport. For example, at a flow rate of 50 ml·min<sup>-1</sup>, the CHF and HTC of this design in the forward direction are about 30.6 W·cm<sup>-2</sup> and 49.7 kW·m<sup>-2</sup>K<sup>-1</sup>, respectively, accompanied by significant enhancements of 57.4 % and 106.7 %, respectively, in contrast to the heat sink with plain wall microchannels. Additionally, the standard deviations (STD) of wall temperature and pressure drop of the conventional heat sink are 17.1 and 12.6 times higher than that of this new heat sink. Visualization studies were conducted to elucidate the working mechanism of Tesla valves in regulating vapor backflow.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":"Article 126366"},"PeriodicalIF":5.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538321","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 investigation on the effects of inclined grooves on flow boiling heat transfer and instability in a minichannel heat sink 斜槽对微型通道散热器中流动沸腾传热和不稳定性影响的实验研究
IF 5 2区 工程技术
International Journal of Heat and Mass Transfer Pub Date : 2024-10-26 DOI: 10.1016/j.ijheatmasstransfer.2024.126333
Yongrui Bian , Zhen Chen , Zhenzhou Li , Yuxiang Liang , Yuetong Li , Xu Lu , Ding Yuan , Zhenfei Feng
{"title":"Experimental investigation on the effects of inclined grooves on flow boiling heat transfer and instability in a minichannel heat sink","authors":"Yongrui Bian ,&nbsp;Zhen Chen ,&nbsp;Zhenzhou Li ,&nbsp;Yuxiang Liang ,&nbsp;Yuetong Li ,&nbsp;Xu Lu ,&nbsp;Ding Yuan ,&nbsp;Zhenfei Feng","doi":"10.1016/j.ijheatmasstransfer.2024.126333","DOIUrl":"10.1016/j.ijheatmasstransfer.2024.126333","url":null,"abstract":"<div><div>Composite cooling technology combining micro/minichannel and flow boiling has shown great potential in enhancing heat transfer. However, improving their heat transfer efficiency and reducing flow boiling instability is necessary for high heat flux devices to achieve more efficient operation. Therefore, this work first designs a minichannel heat sink with inclined grooves at the bottom and experimentally investigates two-phase flow boiling heat transfer under three mass fluxes (138.8, 230.32, and 331.90 kg/m<sup>2</sup>·s) and two inlet temperatures (70 and 80 °C). The minichannel with a length, width, and height of 200 mm, 2 mm, and 2 mm, respectively. The grooves are evenly arranged at the bottom of the minichannel, with a depth and width of 0.5 mm and an inclination angle of 45° to the flow direction. Results show that the inclined grooves not only provide more nucleation sites to generate more bubbles but also hinder the excessive growth and coalescence of bubbles, delaying the transition from bubbly flow to annular flow. In addition, compared to the smooth minichannel heat sink, the minichannel heat sink with bottom groove can achieve boiling at lower wall superheat and smaller effective heat flux, and the onset of nucleate boiling is advanced. When the inlet temperature is <em>T</em><sub>in</sub>=80 °C and the mass flux is <em>G</em> ≈ 138.81 kg/(m<sup>2</sup>·s), the maximum average heat transfer coefficient of the minichannel heat sink with bottom grooves in the two-phase region is 30.70 kW/(m<sup>2</sup>·K), which is 18.31 % higher than that of the smooth minichannel heat sink. Moreover, the inclined grooves at the bottom generally reduce pressure drop, yield an excellent net effect for heat transfer intensification, and mitigate flow boiling instability. Therefore, this work demonstrates that setting inclined grooves at the bottom of minichannel heat sinks can significantly improve their overall performance and provide a reference for enhancing two-phase boiling heat transfer.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":"Article 126333"},"PeriodicalIF":5.0,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529962","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
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