International Communications in Heat and Mass Transfer最新文献

{"title":"Experimental and numerical study of turbulent fluid flow of jet impingement on a solid block in a confined duct with baffles","authors":"A. Abdel-Fattah,&nbsp;E. Wahba,&nbsp;A.-F. Mahrous","doi":"10.1016/j.icheatmasstransfer.2024.108294","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108294","url":null,"abstract":"<div><div>This study investigates the heat transfer and fluid flow characteristics of turbulent flow resulting from jet impingement on a heated solid block positioned on the lower wall of a duct with baffles. Both experimental and numerical methods were employed in this research. The flow was presumed to be three-dimensional, steady, incompressible, and turbulent. The study involved the installation of one baffle on the lower wall and another one on the upper wall. Three variants of the k-ε turbulence model (the standard, the RNG, and the realizable) were numerically compared. The realizable k-ε model has shown the most reliable results compared to the other models, and thus is utilized in all calculations.</div><div>The flow characteristics were experimentally and numerically studied by varying jet Reynolds number (38,957 ≤ Re ≤ 77,315), baffle height (h_b /d = 0.6,0.8 and 1.0), baffles' locations arrangement [(L₁/d with L₂/d) as (3 with 4), (4 with 6), (6 with 8) and (6 with 4)], solid block temperature (333 ^o K ≤ T_b ≤ 363 ^o K) at an aspect ratio (w/a) of 5.25.</div><div>The results showed that several vortices were formed: a main vortex close to the upper wall, a smaller one above the hot solid block, a vortex adjacent to the solid block, and additional vortex zones both in front of and behind the lower and upper baffles. The vortices intensity increases as the Reynolds number grows up. When the baffle locations change downstream, the sizes of these generated vortices increase, the height of the recirculation zone behind the lower baffle is slightly higher than that behind the upper baffle, and the primary vortex diminishes. Besides, all recirculation zones grow up in sizes when swapping the baffle locations.</div><div>The study also revealed that the pressure is higher when the baffle is presented in the domain than the case of no baffle. The pressure value at the stagnation point, peak sub-atmospheric pressure value and maximum pressure value increase as the Reynolds number increases. They also increase with the increase of baffle height. However, it was found that the pressure values decay when the positions of the baffles get changed in the downstream direction.</div><div>In addition, the results showed that the maximum deviation in temperature between the experimental and theoretical results was about 3 %. Besides, the increase in the maximum temperature value in the presence of baffles was about 10.8 % as compared to the case without baffles. Furthermore, the temperature increases as the Reynolds number decreases while it increases with the increase of solid block temperature and/or baffles height and location.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108294"},"PeriodicalIF":6.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759753","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":"Investigation of asymmetric heating in Poiseuille-Rayleigh-Bénard water flow: A numerical study","authors":"Aymen Benbeghila ,&nbsp;Riadh Ouzani ,&nbsp;Ammar Benderradji ,&nbsp;Chérifa Abid ,&nbsp;Sofiane Khelladi","doi":"10.1016/j.icheatmasstransfer.2024.108404","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108404","url":null,"abstract":"<div><div>In this paper, a numerical investigation of the impact of asymmetric heating on laminar mixed convection in Poiseuille-Rayleigh-Bénard water flow within parallel horizontal channels is presented. The study has been carried out in a rectangular channel with a transverse aspect ratio of 10, and considered both low (<em>Ra</em> = 1.28 × 10⁴) and high (<em>Ra</em> = 1.4 × 10⁵) Rayleigh numbers, with Reynolds numbers of 50 and 100. A uniform heat flux was applied to the top and bottom walls of the heated region to assess its effect on the system's thermoconvective behavior and heat transfer efficiency. Two flux ratio scenarios were considered: q_t/q_b = 1 and q_t/q_b = 2.</div><div>The results indicate that increasing the flux ratio intensifies the destabilizing temperature gradient and significantly enhances buoyancy-induced flow, thereby influencing the patterns of thermoconvective structures. Specifically, flux ratios lead to an increased number of plumes originating from the bottom of the channel, while reducing their height and confining them between the bottom wall and the upper thermal boundary layer. It is also observed that flux ratios do not affect the mechanisms involved in the formation of longitudinal rolls. Furthermore, at low Rayleigh numbers, asymmetric heating has a pronounced impact on the establishment length. In contrast, this effect diminishes and becomes negligible at higher Rayleigh numbers. Numerical computations further reveal that near the bottom wall, the Nusselt number exhibits singular behavior, approaching infinity. Regardless of Reynolds and Rayleigh numbers, flux ratios significantly enhance heat transfer within the system. Additionally, near the top wall, the buoyancy effects from the bottom wall have negligible impact on heat transfer, except in the case where q_t/q_b = 2, <em>Re</em> = 50 and <em>Ra</em> = 1.4 × 10⁵, where instability in the upper thermal layer was observed.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108404"},"PeriodicalIF":6.4,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743524","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 research on geothermal energy extraction in backfilled mines by using the excellent heat transfer performance of loop heat pipe","authors":"Xueli Wang ,&nbsp;Pengju Zhang ,&nbsp;Xuquan Dong ,&nbsp;Jingyu Wang ,&nbsp;Jiabin Fang ,&nbsp;Xiaoyan Zhang ,&nbsp;Lang Liu","doi":"10.1016/j.icheatmasstransfer.2024.108385","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108385","url":null,"abstract":"<div><div>Deep mine harbor substantial geothermal energy. Integrating a heat exchanger within the backfill body mitigates thermal hazards and facilitates the concurrent extraction of mineral and geothermal resources. Inspired by the capabilities of superior thermal conductivity, high heat transfer limit without additional energy consumption of loop heat pipe (LHP), a novel cemented paste backfill system coupled with an LHP heat exchanger (LHPHE-CPB) was developed to effectively improve the thermal conductivity of backfill body and enhance the extraction performance of geothermal energy in backfilled mines. The temperature evolutions of LHPHE-CPB system and the mechanisms of vapor-liquid phase transition and two-phase flow within LHP were numerically analyzed during the stages of heat storage and simultaneous heat storage/heat release. Orthogonal tests meticulously examined the effects of surrounding rock temperature, and the inlet temperature and flow rate of cooling water on the system's heat transfer performance. Optimal operating conditions for the system, in terms of reducing backfill body temperature, achieving favorable temperature differentials between the inlet and outlet cooling water, and enhancing the heat extraction capacity of system, were determined through range and variance analyses. This research establishes a theoretical foundation for the application of LHP in efficiently extracting geothermal energy from backfilled mines.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108385"},"PeriodicalIF":6.4,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743523","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":"Non-isothermal wicking in polymer sintered bead wicks: Experimentation, analytical solutions, and numerical validation","authors":"Abul Borkot Md Rafiqul Hasan,&nbsp;Krishna M. Pillai,&nbsp;Jordan Piontkowski","doi":"10.1016/j.icheatmasstransfer.2024.108384","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108384","url":null,"abstract":"<div><div>Though models and applications abound for spontaneous imbibition of liquids into porous media (also called wicking), this is perhaps the first attempt to propose (and rigorously test) any model under non-isothermal conditions. This paper evaluates non-isothermal wicking phenomena through experiments, theoretical models, and numerical simulations. Experiments measure the wicking height of hexadecane in a heated beaker with a polypropylene wick at room temperature. An analytical solution predicts the wicking rate based on temperature-sensitive liquid properties, such as viscosity, surface tension, and density. Three temperature models are introduced: Liquid Temperature Model, Average Temperature Model, and Dynamic Temperature Model. The first two models incorporate temperature-induced changes in liquid properties but have limitations. The Liquid Temperature Model overestimates wicking height, while the Average Temperature Model improves predictions but still faces challenges. The Dynamic Temperature Model, using numerical simulation, accurately calculates fluid properties at dynamically determined temperatures, leading to better predictions of wicking height. Comparisons with experimental data show increasing accuracy across the three models. The Dynamic Temperature Model also successfully demonstrates temperature transitions in the wick observed through thermal imaging.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108384"},"PeriodicalIF":6.4,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142742916","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":"Convective heat transfer of microchannel heat sinks with pinfins and jets for a heat flux up to 500 W/cm2","authors":"Xue Zhang ,&nbsp;Puhang Jin ,&nbsp;Gongnan Xie","doi":"10.1016/j.icheatmasstransfer.2024.108381","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108381","url":null,"abstract":"<div><div>This study proposes a kind of jet impingement microchannel heat sink with pinfins and then investigates the effects of jets arragement, pinfins placement angle, and pinfins shape on the flow characteristics and heat transfer of various heat sinks. It is found that the arrangement of jets has a minor influence on the flow pressure drop but has a significant influence on the heat transfer. Considering the heat transfer coefficient and pressure drop, the 5 × 6 array jet heat sink performs the best. The shape and placement angle of pinfins greatly affect the flow characteristics and heat transfer. Elliptical fins have a more advantageous influence on the overall performance of the heat sink compared with rectangular fins. The angle of the elliptical fins corresponding to maximum thermal performance factor value decreases with Reynolds number, the trend not seen in rectangular fins. The maximum thermal performance factor of heat sink, with rectangular fins at the angle of 15° is increase by 6.73 %, and it is increased by 7.86 % for the case with elliptical fins at the angle of 30°. The numerical simulations of the present design are justified by the analysis from the perspectives of entropy generation and Field Synergy Principle.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108381"},"PeriodicalIF":6.4,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743525","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":"Mechanistic model of wall heat transfer for vertical subcooled boiling flow","authors":"Manh Long Doan,&nbsp;Jinyeong Bak,&nbsp;Youngchang Ko,&nbsp;Jae Jun Jeong,&nbsp;Byongjo Yun","doi":"10.1016/j.icheatmasstransfer.2024.108389","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108389","url":null,"abstract":"<div><div>Nucleate boiling rate is significantly affected by heat flux partitioning from the heated wall during subcooled boiling flow. Therefore, precisely modeling wall heat flux partitioning is crucial for the realistic prediction of boiling two-phase flows. In this study, a new mechanistic model based on bubble dynamics and associated heat transfer mechanisms is proposed for wall heat flux partitioning under vertical subcooled boiling flow. The proposed model categorizes the wall heat flux into four components: evaporation, nucleation quenching, sliding transient conduction, and forced convection. Unlike previous models, the nucleation quenching and sliding transient conduction components, both triggered by sliding bubbles, are modeled separately owing to their different active times in the new model. Additionally, the proposed model incorporates suppression factors into the existing model for nucleation site density to address boiling suppressions induced by subcooled liquid and static bubble interactions. Evaluation results reveal that the new model, including its closure models, exhibits a good prediction capability in a wide range of thermal-hydraulic conditions covering 298–3527 kg/m²s of mass flux, 100–6000 kW/m² of heat flux, 5–83.3 K of liquid subcooling, and 1–6 bar of pressure.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108389"},"PeriodicalIF":6.4,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142742917","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":"Effect of statistical positional correlation on the radiative property investigation of dispersed particulate medium","authors":"Zhang Aoyu ,&nbsp;Wang Fuqiang ,&nbsp;Zou Huichuan ,&nbsp;Song Jintao ,&nbsp;Cheng Ziming ,&nbsp;Xu Jie","doi":"10.1016/j.icheatmasstransfer.2024.108396","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108396","url":null,"abstract":"<div><div>Spectral radiative transfer between particles of dispersed particulate medium is prevalent in various fields, which may be affected by particle distribution when considering dependent scattering effect (DSE). Meanwhile, statistical positional correlation (SPC) describes the possible existing order of particle distribution in the spatial variation for disordered dispersed particulate medium. SPC plays a pivotal role in the transformation of radiative transfer regimes between particles. However, the existing theory lacks a precise criterion for describing SPC and fails to comprehensively consider key factors within SPC influencing radiative transfer regimes, such as mean distance, relative distance, standard deviation, cluster, and aggregation. To achieve more representative and accurate results of radiative property calculations while minimizing computational resources, we proposed MRSDL (Mean distance, Relative distance, Standard deviation, Density-based clustering, and Line matrix) criterion combined with particle swarm optimization (PSO) for characterizing and regulating SPC. Moreover, to further achieve the statistical averaging of radiative properties precisely, the multiple sphere T-matrix (MSTM) method is combined to eliminate the random fluctuations of radiative properties caused by SPC. Compared to the conventional method, the method by authors can decrease error between experimental and calculation data from 41.23 % to 5.32 %, when considering the effect of SPC on the radiative property.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108396"},"PeriodicalIF":6.4,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743522","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":"Computational study of flow boiling heat transfer enhancement in Grooved Wall channels","authors":"A.R. Mallah ,&nbsp;Omer A. Alawi ,&nbsp;A. Ataki ,&nbsp;H.G. Svavarsson ,&nbsp;Waqar Ahmed ,&nbsp;G. Sævarsdóttir","doi":"10.1016/j.icheatmasstransfer.2024.108392","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108392","url":null,"abstract":"<div><div>Using specially structured surfaces such as a grooved surface to enhance the flow boiling heat transfer has many advantages; it enhances the ebullition cycle of the nucleate boiling and improves the two-phase flow on the heated wall, significantly boosting the heat transfer coefficient. The grooves allow surface tension forces to play a role during the boiling process under certain conditions, which also assists in the creation and detachment of the bubbles. This study employed a computational study based on a mechanistic flow-boiling model to simulate the flow for the subcooled boiling phenomenon on grooved surfaces. Bubble creation, growth, and departure were computationally studied for various wall structures: smooth wall, V-shaped grooved wall, and U-shaped grooved wall. The results were validated by comparing them to an experimental study in terms of the bubbles' creation and departure parameters. The results reveal a significant improvement in thermal efficiency following U-shaped grooved wall use.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108392"},"PeriodicalIF":6.4,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721099","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 of jet-regeneration composite cooling systems: An analysis of flow mode and distribution utilizing supercritical n-decane and ambient air","authors":"Jin Zhang ,&nbsp;Yong Li ,&nbsp;Jie Li ,&nbsp;Yingchun Zhang ,&nbsp;Jiajie Zhang ,&nbsp;Bengt Sunden ,&nbsp;Gongnan Xie","doi":"10.1016/j.icheatmasstransfer.2024.108382","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108382","url":null,"abstract":"<div><div>To enhance the heat transfer performance of the scramjet, this paper conducts research and analysis on the impact of flow mode and flow distribution of supercritical n-decane and ambient air on flow and heat transfer characteristics, based on regeneration cooling channels. Given the disparities in fluid flow characteristics within the channel, the three flow configurations exhibit varying degrees of heat transfer deterioration. In the jet single outlet flow mode, the fluid mobility within the channel is relatively poor, leading to the most pronounced deterioration of heat transfer. The combined heat transfer performance between the jet fluid and the crossflow fluid is predominantly influenced by the number of jets and the distribution ratio of flow rates. Notably, the jet-crossflow single outlet arrangement exhibits exceptional heat transfer capabilities when the jet flow rate constitutes a relatively low proportion (12.5 %) while the crossflow flow rate is substantial (87.5 %). Ambient air, with its lower density, arrives at the heated surface with significantly higher velocities and greater turbulence intensity compared to supercritical n-decane. As the number of jet holes increases, the inhomogeneity (<em>R</em>) in the Nusselt number gradually diminishes. For most configurations, <em>R</em> is more pronounced in ambient air than in supercritical n-decane.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108382"},"PeriodicalIF":6.4,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721297","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 study on gas-liquid transport uniformity in full-scale flow field of proton exchange membrane fuel cells","authors":"Fei Dong,&nbsp;Wenshan Qin,&nbsp;Sheng Xu,&nbsp;Huaisheng Ni","doi":"10.1016/j.icheatmasstransfer.2024.108395","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108395","url":null,"abstract":"<div><div>Distribution zone governs airflow transmission and distribution within large-scale flow field, which further affects the discharge of liquid water produced. This paper combines experimental validation and computational fluid dynamics (CFD) methods to elevate mass transfer coherence in full-scale flow field (375 cm²). For the first time, circulation number <span><math><mi>λ</mi></math></span> and drainage maldistribution (DM) are introduced to quantify variations in water and gas transport homogeneity attributable to the distribution zone. Effect on orientation and spacing of dot matrix, as well as main field structure are investigated. The results reveal that full-scale flow field inlet and outlet distribution zones manage the behavior of gas and liquid transport. Specifically, dot matrix flow field with an inclination angle α = 90° demonstrates superior flow uniformity, while α = 45° exhibits the fastest initial drainage rate. Optimal comprehensive mass transfer and drainage consistency are achieved with a vertical dot matrix spacing of S = 1.2 mm ∼ 1.5 mm, yielding the lowest maldistribution factor (MF) and DM number of 0.15 and 0.04 respectively. This configuration results in a maximum improvement of 58.4 % and 43.1 %. Notably, a novel aspect is that the drainage rate in full-scale flow field follows an exponential distribution, with peak efficiency factor <em>R</em> = 0.29 observed at α = 90°and S = 1.5 mm.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108395"},"PeriodicalIF":6.4,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721100","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}