Pub Date : 2024-11-27DOI: 10.1016/j.icheatmasstransfer.2024.108391
Yanlong Zhu , Jiaqi Wang , Yanyu Sun , Chenyuan Hong , Changchun Xu , Serhiy Serbin , Daifen Chen
Long-term stability and safety are two key factors for the application of solid oxide fuel cell (SOFC) technology, with thermodynamics playing a central role in influencing this stability. Thus, understanding the thermodynamic behavior within SOFC and how it will depend on the stack structure are very important, especially at the start and stop stages. In this study, a 3D calculated fluid dynamics model and thermomechanical coupling model based on the actual component structures are established. We place emphasis on understanding how these factors evolve during dynamic phases, shedding light on the transient thermal stress behavior of the SOFC. The influence of different interconnect structures on the thermal stress distribution is studied. The coupling calculation results show that the first principal stress of the electrolyte is significantly affected by the specific interconnect structure. Adopting cylindrical ribs instead of rectangular ribs, the thermal stresses of the SOFC components can be reduced by 13–25 %, respectively.
{"title":"Prediction of transient thermal stress distribution in SOFC based on coupled computational fluid dynamics and thermodynamics modeling","authors":"Yanlong Zhu , Jiaqi Wang , Yanyu Sun , Chenyuan Hong , Changchun Xu , Serhiy Serbin , Daifen Chen","doi":"10.1016/j.icheatmasstransfer.2024.108391","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108391","url":null,"abstract":"<div><div>Long-term stability and safety are two key factors for the application of solid oxide fuel cell (SOFC) technology, with thermodynamics playing a central role in influencing this stability. Thus, understanding the thermodynamic behavior within SOFC and how it will depend on the stack structure are very important, especially at the start and stop stages. In this study, a 3D calculated fluid dynamics model and thermomechanical coupling model based on the actual component structures are established. We place emphasis on understanding how these factors evolve during dynamic phases, shedding light on the transient thermal stress behavior of the SOFC. The influence of different interconnect structures on the thermal stress distribution is studied. The coupling calculation results show that the first principal stress of the electrolyte is significantly affected by the specific interconnect structure. Adopting cylindrical ribs instead of rectangular ribs, the thermal stresses of the SOFC components can be reduced by 13–25 %, respectively.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108391"},"PeriodicalIF":6.4,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721098","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}
Pub Date : 2024-11-27DOI: 10.1016/j.icheatmasstransfer.2024.108399
Shuai Sun , Ali B.M. Ali , Shahram Babadoust , Murtadha M. Al-Zahiwat , Raman Kumar , Rahul Raj Chaudhary , Dilsora Abduvalieva , Soheil Salahshour , Nafiseh Emami
This study explored the effect of nanovoid size on the mechanical properties of polymer‑carbon matrices through detailed molecular dynamics simulations. The investigation focused on spherical nanovoids with radii of 5, 7, 10, 12, and 15 Å, evaluating their effects on critical mechanical properties, such as Young's modulus and ultimate strength. The Tersoff potential was employed to accurately model the atomic and mechanical behavior of the polymer‑carbon matrix, considering the presence of these nanovoids. The simulation results indicate that the potential energy and total energy stabilized at −132,279.23 eV and − 131,522.4 eV, respectively, confirming the physical stability of simulated samples. On the other hand, the findings reveal that for a nanovoid radius of 5 Å, the ultimate strength and Young's modulus were 36.41 GPa and 424.93 GPa, respectively. As the radius of nanovoids increased from 5 Å to 15 Å, both ultimate strength and Young's modulus exhibited a decreasing trend, with values dropping from 36.41 GPa and 424.93 GPa to 31.18 GPa and 364.39 GPa, respectively. Moreover, larger nanovoids contributed to increased flexibility and a higher critical strain in the polymer‑carbon matrix. This systematic analysis of nanovoid size effects provided a new perspective on void engineering within composites. By enhancing the theoretical understanding of how void dimensions affected material properties, the study offered significant insights for optimizing the mechanical performance of advanced materials and advancing the field of structural engineering.
本研究通过详细的分子动力学模拟，探讨了纳米形体尺寸对聚合物-碳基质机械性能的影响。研究重点是半径为 5、7、10、12 和 15 Å 的球形纳米空心体，评估它们对杨氏模量和极限强度等关键力学性能的影响。考虑到这些纳米实体的存在，采用了特尔索夫势能来精确模拟聚合物-碳基体的原子和机械行为。模拟结果表明，势能和总能分别稳定在 -132,279.23 eV 和 -131,522.4 eV，证实了模拟样品的物理稳定性。另一方面，研究结果表明，当纳米晶半径为 5 Å 时，极限强度和杨氏模量分别为 36.41 GPa 和 424.93 GPa。随着纳米实体半径从 5 Å 增加到 15 Å，极限强度和杨氏模量均呈下降趋势，分别从 36.41 GPa 和 424.93 GPa 下降到 31.18 GPa 和 364.39 GPa。此外，较大的纳米形体有助于增加聚合物-碳基体的柔韧性和临界应变。这种对纳米空泡尺寸效应的系统分析为复合材料中的空泡工程提供了一个新的视角。通过加强对空隙尺寸如何影响材料性能的理论理解，该研究为优化先进材料的机械性能和推动结构工程领域的发展提供了重要见解。
{"title":"Examination of the mechanical properties of porous carbon matrix by considering the Nanovoids: A computational study using molecular dynamics simulation","authors":"Shuai Sun , Ali B.M. Ali , Shahram Babadoust , Murtadha M. Al-Zahiwat , Raman Kumar , Rahul Raj Chaudhary , Dilsora Abduvalieva , Soheil Salahshour , Nafiseh Emami","doi":"10.1016/j.icheatmasstransfer.2024.108399","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108399","url":null,"abstract":"<div><div>This study explored the effect of nanovoid size on the mechanical properties of polymer‑carbon matrices through detailed molecular dynamics simulations. The investigation focused on spherical nanovoids with radii of 5, 7, 10, 12, and 15 Å, evaluating their effects on critical mechanical properties, such as Young's modulus and ultimate strength. The Tersoff potential was employed to accurately model the atomic and mechanical behavior of the polymer‑carbon matrix, considering the presence of these nanovoids. The simulation results indicate that the potential energy and total energy stabilized at −132,279.23 eV and − 131,522.4 eV, respectively, confirming the physical stability of simulated samples. On the other hand, the findings reveal that for a nanovoid radius of 5 Å, the ultimate strength and Young's modulus were 36.41 GPa and 424.93 GPa, respectively. As the radius of nanovoids increased from 5 Å to 15 Å, both ultimate strength and Young's modulus exhibited a decreasing trend, with values dropping from 36.41 GPa and 424.93 GPa to 31.18 GPa and 364.39 GPa, respectively. Moreover, larger nanovoids contributed to increased flexibility and a higher critical strain in the polymer‑carbon matrix. This systematic analysis of nanovoid size effects provided a new perspective on void engineering within composites. By enhancing the theoretical understanding of how void dimensions affected material properties, the study offered significant insights for optimizing the mechanical performance of advanced materials and advancing the field of structural engineering.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108399"},"PeriodicalIF":6.4,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721096","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}
Pub Date : 2024-11-27DOI: 10.1016/j.icheatmasstransfer.2024.108398
Bin Guo , Ali Basem , As'ad Alizadeh , Akram Shakir Najm , Hamed Kazemi-Varnamkhasti , Dheyaa J. Jasim , Soheil Salahshour
Turbulent natural convection of -water ferrofluid with Reynolds Averaged Navier-Stokes (RANS) based turbulence model of in the presence of wire-induced non-uniform magnetic field inside a porous medium is simulated, numerically. To discretize and solve the related equations the FVM method and SIMPLE algorithm are implemented. For applying the non-uniform magnetic field, two wires carrying electric currents have been installed below and above the enclosure. Simulations are implemented for different Rayleigh numbers (), porosity number of (), volume fractions of nanoparticles magnetic field numbers . According to the results, in low Rayleigh number and high MFN, at the high-volume fraction of nanoparticles, applying a magnetic field optimally influenced transfer and Nusselt number. At high porosity numbers, low Ra numbers and , the heat transfer rate improved by up to 17 %. However, at high Ra numbers and , applying the magnetic field reduces the Nusselt number by almost 12 %.
{"title":"Numerical analysis of turbulent natural convection in the presence of wire-induced non-uniform magnetic field inside a porous medium","authors":"Bin Guo , Ali Basem , As'ad Alizadeh , Akram Shakir Najm , Hamed Kazemi-Varnamkhasti , Dheyaa J. Jasim , Soheil Salahshour","doi":"10.1016/j.icheatmasstransfer.2024.108398","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108398","url":null,"abstract":"<div><div>Turbulent natural convection of <span><math><mi>F</mi><msub><mi>e</mi><mn>3</mn></msub><msub><mi>O</mi><mn>4</mn></msub></math></span>-water ferrofluid with Reynolds Averaged Navier-Stokes (RANS) based turbulence model of <span><math><mi>k</mi><mo>−</mo><mi>ω</mi></math></span> in the presence of wire-induced non-uniform magnetic field inside a porous medium is simulated, numerically. To discretize and solve the related equations the FVM method and SIMPLE algorithm are implemented. For applying the non-uniform magnetic field, two wires carrying electric currents have been installed below and above the enclosure. Simulations are implemented for different Rayleigh numbers (<span><math><msup><mn>10</mn><mn>6</mn></msup><mo>≤</mo><mi>Ra</mi><mo>≤</mo><msup><mn>10</mn><mn>8</mn></msup></math></span>), porosity number of (<span><math><mi>η</mi><mo>=</mo><mn>0.5</mn><mspace></mspace><mtext>and</mtext><mspace></mspace><mn>0.9</mn></math></span>), volume fractions of nanoparticles <span><math><mfenced><mrow><mn>0</mn><mo>≤</mo><mi>ϕ</mi><mo>≤</mo><mn>4</mn><mo>%</mo></mrow></mfenced><mo>,</mo></math></span> magnetic field numbers <span><math><mfenced><mrow><mn>0</mn><mo>≤</mo><mi>MFN</mi><mo>≤</mo><msup><mn>10</mn><mn>9</mn></msup></mrow></mfenced></math></span>. According to the results, in low Rayleigh number and high MFN, at the high-volume fraction of nanoparticles, applying a magnetic field optimally influenced transfer and Nusselt number. At high porosity numbers, low Ra numbers and <span><math><mi>ϕ</mi><mo>=</mo><mn>4</mn><mo>%</mo></math></span>, the heat transfer rate improved by up to 17 %. However, at high <em>Ra</em> numbers and <span><math><mtext>high</mtext><mspace></mspace><mi>ϕ</mi></math></span>, applying the magnetic field reduces the Nusselt number by almost 12 %.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108398"},"PeriodicalIF":6.4,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721097","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}
Pub Date : 2024-11-26DOI: 10.1016/j.icheatmasstransfer.2024.108354
Hongxia Li , Lang Wu , Changshun Xia , Shuiqing Huang , Meiqin Ni , Chunlin Huang , Ming Xu , Zhaohui Ruan
Graphitic carbon nitride ( ) as a kind of important 2D materials, shows great potential applications as electric and photoelectric devices. However, most reported works mainly focus on the thermal transport characteristics of monolayer , with bulk ignored, which also has many important applications. Herein, anisotropic thermal conductivity of bulk is investigated with the help of molecular dynamics. Considering the unique layer-by-layer structural characteristics, a deep neural network potential (DNNP) is developed, for accurately describing the interlayer vdw interactions among different C-N layers. It has been demonstrated that DNNP can accurately describe the atomic interactions in , which is the weakness of classical potential fields. With the help of DNNP, phonon density of states, thermal conductivities, mechanical properties of monolayer, Bi-layer and Tri-layer are fully investigated, and the relationship among atomic structures, structural symmetry and thermal conductivity is discussed, and mechanisms on vdW interactions making difference to thermal conductivity of are illustrated on. The anisotropic thermal conductivity of bulk is evaluated, showing that the thermal conductivity perpendicular to the C-N planes is 1.40 Wm−1K−1 which is about 1/3 of that along with C-N plane (4.41 and 4.12 Wm−1K−1 in x and y direction, respectively).
{"title":"A deep neural network potential model for theoretically predicting thermal transport, mechanical properties of multi-layered graphitic carbon nitride with molecular dynamics","authors":"Hongxia Li , Lang Wu , Changshun Xia , Shuiqing Huang , Meiqin Ni , Chunlin Huang , Ming Xu , Zhaohui Ruan","doi":"10.1016/j.icheatmasstransfer.2024.108354","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108354","url":null,"abstract":"<div><div>Graphitic carbon nitride ( <figure><img></figure> ) as a kind of important 2D materials, shows great potential applications as electric and photoelectric devices. However, most reported works mainly focus on the thermal transport characteristics of monolayer <figure><img></figure> , with bulk <figure><img></figure> ignored, which also has many important applications. Herein, anisotropic thermal conductivity of bulk <figure><img></figure> is investigated with the help of molecular dynamics. Considering the unique layer-by-layer structural characteristics, a deep neural network potential (DNNP) is developed, for accurately describing the interlayer vdw interactions among different C-N layers. It has been demonstrated that DNNP can accurately describe the atomic interactions in <figure><img></figure> , which is the weakness of classical potential fields. With the help of DNNP, phonon density of states, thermal conductivities, mechanical properties of monolayer, Bi-layer and Tri-layer <figure><img></figure> are fully investigated, and the relationship among atomic structures, structural symmetry and thermal conductivity is discussed, and mechanisms on vdW interactions making difference to thermal conductivity of <figure><img></figure> are illustrated on. The anisotropic thermal conductivity of bulk <figure><img></figure> is evaluated, showing that the thermal conductivity perpendicular to the C-N planes is 1.40 Wm<sup>−1</sup>K<sup>−1</sup> which is about 1/3 of that along with C-N plane (4.41 and 4.12 Wm<sup>−1</sup>K<sup>−1</sup> in x and y direction, respectively).</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108354"},"PeriodicalIF":6.4,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721113","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}
Pub Date : 2024-11-26DOI: 10.1016/j.icheatmasstransfer.2024.108380
Mehran Sharifi , Narin Rasouli
This review investigates Double Diffusive Convection (DDC), a phenomenon where heat and solute concentration diffuse at differing rates, resulting in complex flow dynamics influenced by temperature and concentration gradients. DDC plays a crucial role in various natural and engineered systems, including oceanography, energy systems, and astrophysical contexts. This article synthesizes recent research on flow, heat, and mass transfer in DDC, emphasizing the effects of diverse flow geometries and external forces, including porous media. It examines critical parameters such as buoyancy ratio (), aspect ratio (), Prandtl (), Reynolds (), Rayleigh (), and Lewis () numbers, alongside the Hartmann (), Soret (), and Dufour () numbers, highlighting their influence on velocity profiles, entropy generation, and heat/mass transfer rates quantified by Nusselt () and Sherwood () numbers. The review underscores the significant impact of geometry on DDC outcomes, demonstrating that configurations like rectangular and porous cavities enhance heat transfer efficiencies at elevated Rayleigh numbers. The introduction of nanofluids and variable porosity in porous media further optimizes thermal performance. Additionally, magnetic fields and rotation introduce complexities in flow stability and transfer efficiency, with higher Hartmann numbers leading to a transition from convection-dominated to conduction-dominated heat transfer. The interaction of thermal and solutal diffusion in porous media reveals transitions in stability, influencing flow patterns and convective currents. This comprehensive analysis highlights the vital role of geometrical configurations, fluid properties, and external forces in advancing DDC applications across diverse contexts.
{"title":"A comprehensive review of double diffusive convection: Effects of flow geometries, external forces, and porous media","authors":"Mehran Sharifi , Narin Rasouli","doi":"10.1016/j.icheatmasstransfer.2024.108380","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108380","url":null,"abstract":"<div><div>This review investigates Double Diffusive Convection (DDC), a phenomenon where heat and solute concentration diffuse at differing rates, resulting in complex flow dynamics influenced by temperature and concentration gradients. DDC plays a crucial role in various natural and engineered systems, including oceanography, energy systems, and astrophysical contexts. This article synthesizes recent research on flow, heat, and mass transfer in DDC, emphasizing the effects of diverse flow geometries and external forces, including porous media. It examines critical parameters such as buoyancy ratio (<span><math><mi>BR</mi></math></span>), aspect ratio (<span><math><mi>AR</mi></math></span>), Prandtl (<span><math><mi>PR</mi></math></span>), Reynolds (<span><math><mo>Re</mo></math></span>), Rayleigh (<span><math><mi>Ra</mi></math></span>), and Lewis (<span><math><mi>Le</mi></math></span>) numbers, alongside the Hartmann (<span><math><mi>Ha</mi></math></span>), Soret (<span><math><mi>Sr</mi></math></span>), and Dufour (<span><math><mi>Du</mi></math></span>) numbers, highlighting their influence on velocity profiles, entropy generation, and heat/mass transfer rates quantified by Nusselt (<span><math><mi>Nu</mi></math></span>) and Sherwood (<span><math><mi>Sh</mi></math></span>) numbers. The review underscores the significant impact of geometry on DDC outcomes, demonstrating that configurations like rectangular and porous cavities enhance heat transfer efficiencies at elevated Rayleigh numbers. The introduction of nanofluids and variable porosity in porous media further optimizes thermal performance. Additionally, magnetic fields and rotation introduce complexities in flow stability and transfer efficiency, with higher Hartmann numbers leading to a transition from convection-dominated to conduction-dominated heat transfer. The interaction of thermal and solutal diffusion in porous media reveals transitions in stability, influencing flow patterns and convective currents. This comprehensive analysis highlights the vital role of geometrical configurations, fluid properties, and external forces in advancing DDC applications across diverse contexts.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108380"},"PeriodicalIF":6.4,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721101","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}
Pub Date : 2024-11-26DOI: 10.1016/j.icheatmasstransfer.2024.108390
Xiaojing Ma , Zihao Wu , Jinliang Xu , Songhe Wang , Haoran Hong
Exploring energy within boiling system is becoming an effective way to enhance heat transfer nowadays. Novel bubble-driven heater has great potential to achieve it. However, heater dynamics in this technique are crucial but unclear in previous studies. Here, boiling on a movable suspended heater with the same density of liquid was simulated to investigate heater dynamics and corresponding mechanisms in detail. Smaller departure diameter and higher frequency were found on movable heater. Periodical up-down motion was observed and the upward movement only occurred at high heat fluxes. Up-down motion contributed to small dry spot diameter and rapid cold liquid supply. The mechanism of different motion over entire bubble cycle was investigated for the first time. Heater moved downwards due to evaporation momentum force () and add mass force () during the initial bubble growth stage with expanding triple line, moved upwards due to surface tension force () during bubble growth period with nearly constant triple line, and it moved downwards again due to when bubble departed. and which impeded bubble departure before were found benefit departure by induced movable heater. Heater manipulation mechanism was found and our study would benefit the design of smart and automatic heater.
如今，在沸腾系统中探索能量已成为加强热传递的有效方法。新型气泡驱动加热器具有实现这一目标的巨大潜力。然而，该技术中的加热器动力学至关重要，但以往的研究并不清楚。在此，我们模拟了液体密度相同的可移动悬浮加热器上的沸腾，以详细研究加热器的动力学和相应机制。结果发现，活动加热器上的偏离直径较小，频率较高。观察到周期性的上下运动，只有在高热流量时才会出现向上运动。自上而下的运动导致干斑直径较小，冷液供应较快。首次研究了整个气泡周期内不同运动的机理。在三重线不断扩大的气泡生长初期，加热器受蒸发动量力（Fe）和质量增加力（Fa）的作用而向下运动；在三重线几乎不变的气泡生长期，加热器受表面张力（Fs）的作用而向上运动；当气泡离开时，加热器又受 Fa 的作用而向下运动。发现之前阻碍气泡离开的 Fa 和 Fe 有利于诱导活动加热器的离开。我们发现了加热器的操纵机制，我们的研究将有助于智能和自动加热器的设计。
{"title":"Bubble-driven heater dynamics in saturated pool boiling","authors":"Xiaojing Ma , Zihao Wu , Jinliang Xu , Songhe Wang , Haoran Hong","doi":"10.1016/j.icheatmasstransfer.2024.108390","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108390","url":null,"abstract":"<div><div>Exploring energy within boiling system is becoming an effective way to enhance heat transfer nowadays. Novel bubble-driven heater has great potential to achieve it. However, heater dynamics in this technique are crucial but unclear in previous studies. Here, boiling on a movable suspended heater with the same density of liquid was simulated to investigate heater dynamics and corresponding mechanisms in detail. Smaller departure diameter and higher frequency were found on movable heater. Periodical up-down motion was observed and the upward movement only occurred at high heat fluxes. Up-down motion contributed to small dry spot diameter and rapid cold liquid supply. The mechanism of different motion over entire bubble cycle was investigated for the first time. Heater moved downwards due to evaporation momentum force (<span><math><msub><mi>F</mi><mi>e</mi></msub></math></span>) and add mass force (<span><math><msub><mi>F</mi><mi>a</mi></msub></math></span>) during the initial bubble growth stage with expanding triple line, moved upwards due to surface tension force (<span><math><msub><mi>F</mi><mi>s</mi></msub></math></span>) during bubble growth period with nearly constant triple line, and it moved downwards again due to <span><math><msub><mi>F</mi><mi>a</mi></msub></math></span> when bubble departed. <span><math><msub><mi>F</mi><mi>a</mi></msub></math></span> and <span><math><msub><mi>F</mi><mi>e</mi></msub></math></span> which impeded bubble departure before were found benefit departure by induced movable heater. Heater manipulation mechanism was found and our study would benefit the design of smart and automatic heater.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108390"},"PeriodicalIF":6.4,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721151","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}
Pub Date : 2024-11-26DOI: 10.1016/j.icheatmasstransfer.2024.108393
Sabir Rasheed , Muzaffar Ali , Hassan Ali , Nadeem Ahmed Sheikh , Guiqiang Li
Cooling demand is escalating because of the climate change and population growth in emerging nations. One of the today's concerns is meeting exponentially raising cooling requirements. Additionally, sustainable development goals (SDGs) such as SDG 03, SDG 07, and SDG 13 emphasize the need of environmentally friendly cooling techniques for human thermal comfort. Therefore, it is essential to develop novel approaches for cooling indoor spaces. The current study presents the design evolution of a Maisotsenko cycle-based indirect evaporative air-cooling system (IEC), with a focus on air-water flow patterns, structural design, and the improved energy efficiency by utilizing locally accessible low-cost polymeric materials. This study also comprises a thorough experimental investigation of an indirect evaporative cooling system by developing multiple configurations (Config) of heat and mass exchangers at the stack level. The experimental findings demonstrate that thermal efficiency of the IECs enhances by increasing the ambient air temperature and wetted area in wet channels. Overall, the resultant wetbulb and dewpoint effectiveness of Config 1-Config 6 vary from 0.29 to 1.12 and 0.22 to 0.86, respectively. Moreover, the configuration 6 has the maximum cooling capacity, coefficient of performance (COP), and energy efficiency ratio (EER) of 2.07 kW, 6.91, and 23.59, respectively under control conditions by utilizing the air conditioning laboratory unit. The results clearly indicate that proposed design configurations incorporating polymeric materials, having high CC and EER, are more effective for air-cooling in hot and dry climate conditions.
{"title":"Design evolution of indirect evaporative air-cooling system through multiple configurations for the enhancement of heat and mass transfer mechanism","authors":"Sabir Rasheed , Muzaffar Ali , Hassan Ali , Nadeem Ahmed Sheikh , Guiqiang Li","doi":"10.1016/j.icheatmasstransfer.2024.108393","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108393","url":null,"abstract":"<div><div>Cooling demand is escalating because of the climate change and population growth in emerging nations. One of the today's concerns is meeting exponentially raising cooling requirements. Additionally, sustainable development goals (SDGs) such as SDG 03, SDG 07, and SDG 13 emphasize the need of environmentally friendly cooling techniques for human thermal comfort. Therefore, it is essential to develop novel approaches for cooling indoor spaces. The current study presents the design evolution of a Maisotsenko cycle-based indirect evaporative air-cooling system (IEC), with a focus on air-water flow patterns, structural design, and the improved energy efficiency by utilizing locally accessible low-cost polymeric materials. This study also comprises a thorough experimental investigation of an indirect evaporative cooling system by developing multiple configurations (Config) of heat and mass exchangers at the stack level. The experimental findings demonstrate that thermal efficiency of the IECs enhances by increasing the ambient air temperature and wetted area in wet channels. Overall, the resultant wetbulb and dewpoint effectiveness of Config 1-Config 6 vary from 0.29 to 1.12 and 0.22 to 0.86, respectively. Moreover, the configuration 6 has the maximum cooling capacity, coefficient of performance (COP), and energy efficiency ratio (EER) of 2.07 kW, 6.91, and 23.59, respectively under control conditions by utilizing the air conditioning laboratory unit. The results clearly indicate that proposed design configurations incorporating polymeric materials, having high CC and EER, are more effective for air-cooling in hot and dry climate conditions.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108393"},"PeriodicalIF":6.4,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721102","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}
Pub Date : 2024-11-25DOI: 10.1016/j.icheatmasstransfer.2024.108374
Md. Asaduzzaman Sourov , A.K.M. Monjur Morshed , Amitav Tikadar , Titan C. Paul
This study investigated an interconnected microchannel (IMCHS) thermal management system using the flow boiling of HFE-7100, focusing on enhanced heat transfer by confining a two-phase mixture within the IMCHS. The interconnection channels were designed to promote continuous thermal boundary layer disruption and improve mixing, facilitating the exploration of suitable microchannel geometry. Contour plots were utilized to visualize key flow phenomena, with attention given to the instabilities induced by the interconnectors, as indicated by local non-dimensional fluctuations in pressure, temperature, and velocity fields. Six different geometric configurations were analyzed and compared with conventional parallel microchannels by varying the width and location of interconnectors, while maintaining a constant aspect ratio of 1. Four distinct mass fluxes (280.4, 560.8, 841.2, and 1121.6 kg/m2s) were applied in counterflow, along with a constant heat flux of 40 W/cm2 at the sink bottom, to assess the thermal and hydraulic performance. Key parameters, such as pressure drop penalty, Nusselt number, thermal resistance, and total vapor fractions, were evaluated at varying mass fluxes. The performance analysis revealed a maximum reduction in pressure drop penalty of around 30 % at 560.8 kg/m2s. Moreover, a significant improvement in the Nusselt number (approximately 34 %) and a reduction in thermal resistance (about 23 %) were observed at 1121.6 kg/m2s. These improvements in thermal and hydraulic performance enabled effective dissipation of high heat fluxes while reducing the pumping power requirement, providing a guideline for future design.
{"title":"Impact of interconnectors on the thermal and hydraulic performances of microchannel heat sink utilizing flow boiling of HFE-7100: A numerical study","authors":"Md. Asaduzzaman Sourov , A.K.M. Monjur Morshed , Amitav Tikadar , Titan C. Paul","doi":"10.1016/j.icheatmasstransfer.2024.108374","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108374","url":null,"abstract":"<div><div>This study investigated an interconnected microchannel (IMCHS) thermal management system using the flow boiling of HFE-7100, focusing on enhanced heat transfer by confining a two-phase mixture within the IMCHS. The interconnection channels were designed to promote continuous thermal boundary layer disruption and improve mixing, facilitating the exploration of suitable microchannel geometry. Contour plots were utilized to visualize key flow phenomena, with attention given to the instabilities induced by the interconnectors, as indicated by local non-dimensional fluctuations in pressure, temperature, and velocity fields. Six different geometric configurations were analyzed and compared with conventional parallel microchannels by varying the width and location of interconnectors, while maintaining a constant aspect ratio of 1. Four distinct mass fluxes (280.4, 560.8, 841.2, and 1121.6 kg/m<sup>2</sup>s) were applied in counterflow, along with a constant heat flux of 40 W/cm<sup>2</sup> at the sink bottom, to assess the thermal and hydraulic performance. Key parameters, such as pressure drop penalty, Nusselt number, thermal resistance, and total vapor fractions, were evaluated at varying mass fluxes. The performance analysis revealed a maximum reduction in pressure drop penalty of around 30 % at 560.8 kg/m<sup>2</sup>s. Moreover, a significant improvement in the Nusselt number (approximately 34 %) and a reduction in thermal resistance (about 23 %) were observed at 1121.6 kg/m<sup>2</sup>s. These improvements in thermal and hydraulic performance enabled effective dissipation of high heat fluxes while reducing the pumping power requirement, providing a guideline for future design.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108374"},"PeriodicalIF":6.4,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699642","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}
Pub Date : 2024-11-25DOI: 10.1016/j.icheatmasstransfer.2024.108383
Abdelraheem M. Aly , Noura Alsedais
This study examines the heat and mass transfer characteristics within a wavy porous cavity filled with nano-enhanced phase change materials (NEPCM), employing the incompressible smoothed particle hydrodynamics (ISPH) and XGBoost models. Key parameters, including the Darcy number () ranging from to , Rayleigh number () from to , fusion temperature () from 0.05 to 0.9, and Soret and Dufour numbers ( and ) up to 0.6, were varied to analyze their impact on heat and mass transfer efficiency. Variable high-temperature and high-concentration zones, extending along the X-axis () from 0.5 to 1.5 and the Y-axis () from 0.4 to 1.6, were found to play a significant role. Simulations reveal that expanding these zones strengthens the velocity field, with resulting in an approximate 35 % increase in flow speed, while smaller values reduce convective currents by up to 26 %. This expansion also enlarges temperature and concentration distributions within the cavity. However, a wider high-temperature and high-concentration region decreases the heat capacity ratio (), while enhancing concentration gradients by 25 %, underscoring NEPCM's potential for optimized thermal and mass transfer. These findings highlight the effectiveness of NEPCM and tailored wavy geometries in achieving superior thermal management and uniform distributions within cavities, with promising applications in advanced thermal systems. Future work will focus on experimental validation and varied geometrical configurations to further refine and expand the model's applicability.
{"title":"Heat and mass transfer of NEPCM in a wavy porous cavity with variable hot and high-concentration zones: A study using ISPH and XGBoost models","authors":"Abdelraheem M. Aly , Noura Alsedais","doi":"10.1016/j.icheatmasstransfer.2024.108383","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108383","url":null,"abstract":"<div><div>This study examines the heat and mass transfer characteristics within a wavy porous cavity filled with nano-enhanced phase change materials (NEPCM), employing the incompressible smoothed particle hydrodynamics (ISPH) and XGBoost models. Key parameters, including the Darcy number (<span><math><mi>Da</mi></math></span>) ranging from <span><math><msup><mn>10</mn><mrow><mo>−</mo><mn>2</mn></mrow></msup></math></span> to <span><math><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math></span>, Rayleigh number (<span><math><mi>Ra</mi></math></span>) from <span><math><msup><mn>10</mn><mn>3</mn></msup></math></span> to <span><math><msup><mn>10</mn><mn>6</mn></msup></math></span>, fusion temperature (<span><math><msub><mi>θ</mi><mi>f</mi></msub></math></span>) from 0.05 to 0.9, and Soret and Dufour numbers (<span><math><mi>Sr</mi></math></span> and <span><math><mi>Du</mi></math></span>) up to 0.6, were varied to analyze their impact on heat and mass transfer efficiency. Variable high-temperature and high-concentration zones, extending along the X-axis (<span><math><msub><mi>L</mi><mi>X</mi></msub></math></span>) from 0.5 to 1.5 and the Y-axis (<span><math><msub><mi>L</mi><mi>Y</mi></msub></math></span>) from 0.4 to 1.6, were found to play a significant role. Simulations reveal that expanding these zones strengthens the velocity field, with <span><math><msub><mi>L</mi><mi>X</mi></msub><mo>=</mo><mn>1.5</mn></math></span> resulting in an approximate 35 % increase in flow speed, while smaller values reduce convective currents by up to 26 %. This expansion also enlarges temperature and concentration distributions within the cavity. However, a wider high-temperature and high-concentration region decreases the heat capacity ratio (<span><math><mi>Cr</mi></math></span>), while enhancing concentration gradients by 25 %, underscoring NEPCM's potential for optimized thermal and mass transfer. These findings highlight the effectiveness of NEPCM and tailored wavy geometries in achieving superior thermal management and uniform distributions within cavities, with promising applications in advanced thermal systems. Future work will focus on experimental validation and varied geometrical configurations to further refine and expand the model's applicability.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108383"},"PeriodicalIF":6.4,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699570","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}
Zeolite is vital for biomass catalytic conversion and high-value utilization. Delving into the intricate mechanisms by which the morphological characteristics of zeolite influence the physicochemical processes involved in biomass conversion holds key to refining zeolite architecture and elevating reaction efficiency. This study established a pore-scale multicomponent reactive transport model based on lattice Boltzmann method to simulate the conversion of glucose to levulinic acid (LA) catalyzed by zeolite, simulation results were in good agreement with experimental results from literature. The zeolite structure is accurately modulated by modeling to systematically investigate the independent effects of each zeolite morphological features on the process. Simulation results revealed that excessively high active components distribution density exerted a detrimental impact on the rehydration of 5-Hydroxymethylfurfural into LA, primarily due to severe coking that impede substance transport and hinder reactants interaction with active sites. It was also unveiled that the reactants transport from liquid phase into zeolite particles stands as a pivotal rate-determining step in the reactive transport process, and a more extensive distribution of mesopores in outer layer of zeolite was identified to enhance the transport efficiency. This study accentuates the importance of morphological engineering in improving LA production and provides a theoretical basis for optimal zeolite design.
沸石对于生物质催化转化和高价值利用至关重要。研究沸石形态特征影响生物质转化过程中物理化学过程的复杂机制，是完善沸石结构、提高反应效率的关键。本研究建立了基于晶格玻尔兹曼法的孔尺度多组分反应输运模型，模拟了沸石催化葡萄糖转化为左旋乙酸（LA）的过程，模拟结果与文献实验结果吻合。通过建模对沸石结构进行精确调控，系统研究了各沸石形态特征对过程的独立影响。模拟结果表明，过高的活性组分分布密度会对 5-羟甲基糠醛再水合成 LA 的过程产生不利影响，这主要是由于严重的结焦现象阻碍了物质的传输，并妨碍了反应物与活性位点的相互作用。研究还发现，反应物从液相传输到沸石颗粒是反应传输过程中决定速率的关键步骤，沸石外层更广泛的中孔分布可提高传输效率。这项研究强调了形态工程在提高 LA 产量方面的重要性，并为沸石的优化设计提供了理论依据。
{"title":"Pore-scale study of zeolite morphology effects on dynamic transport processes and carbon deposition tendencies during glucose appreciation","authors":"Gehao Chen, Xiangqian Wei, Haoyang Wei, Xinyi Zhou, Xinghua Zhang, Longlong Ma","doi":"10.1016/j.icheatmasstransfer.2024.108377","DOIUrl":"10.1016/j.icheatmasstransfer.2024.108377","url":null,"abstract":"<div><div>Zeolite is vital for biomass catalytic conversion and high-value utilization. Delving into the intricate mechanisms by which the morphological characteristics of zeolite influence the physicochemical processes involved in biomass conversion holds key to refining zeolite architecture and elevating reaction efficiency. This study established a pore-scale multicomponent reactive transport model based on lattice Boltzmann method to simulate the conversion of glucose to levulinic acid (LA) catalyzed by zeolite, simulation results were in good agreement with experimental results from literature. The zeolite structure is accurately modulated by modeling to systematically investigate the independent effects of each zeolite morphological features on the process. Simulation results revealed that excessively high active components distribution density exerted a detrimental impact on the rehydration of 5-Hydroxymethylfurfural into LA, primarily due to severe coking that impede substance transport and hinder reactants interaction with active sites. It was also unveiled that the reactants transport from liquid phase into zeolite particles stands as a pivotal rate-determining step in the reactive transport process, and a more extensive distribution of mesopores in outer layer of zeolite was identified to enhance the transport efficiency. This study accentuates the importance of morphological engineering in improving LA production and provides a theoretical basis for optimal zeolite design.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"160 ","pages":"Article 108377"},"PeriodicalIF":6.4,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699644","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}
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