International Journal of Heat and Mass Transfer最新文献_第2页

Numerical investigation on reversible reactive flow inside ribbed channels with different inclined angles

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2025-02-18 DOI: 10.1016/j.ijheatmasstransfer.2025.126820

Ran Yao, Kai Zhang, Sajad Jafari, Christophe Duwig

In accordance with the United Nations Sustainable Development goal #7 – affordable and clean energy, the concept of reversible reactive flow (N₂O₄/NO₂) inside ribbed channel is proposed for low-temperature waste heat recovery. Quasi direct numerical simulations are performed to reveal the relationship between flow, heat/mass transfer, and chemical characteristics with different rib inclined angles (90° and 45°). The analyses indicate that the reaction of N₂O₄ ⇌ 2NO₂ has limited influence on flow patterns inside the ribbed channel, but intensifies the heat transfer considerably. For the 90° reactive case, the enhancement of Nusselt number reaches 112.7 % when Reynolds number is 2000. Although non-equilibrium thermal-chemical phenomenon is observed by instantaneous snapshots, time-averaged results show that the forward endothermic reaction is concentrated close to the heated wall. The flow structures transport fluid pocket consisting of “overheated” gas and triggers local backward exothermic reaction, which decreases the thickness of thermal boundary layer and thereby intensifies the overall heat transfer. For the 45° inclined reactive case, a flow circulation at local equilibrium between heat release and absorption is formed by the rib-induced large-scale vortices. The comprehensive thermal performance is further improved by 24.6 % compared to the 90° reactive case, which attributes to higher Nusselt number and lower friction loss.

{"title":"Numerical investigation on reversible reactive flow inside ribbed channels with different inclined angles","authors":"Ran Yao, Kai Zhang, Sajad Jafari, Christophe Duwig","doi":"10.1016/j.ijheatmasstransfer.2025.126820","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126820","url":null,"abstract":"<div><div>In accordance with the United Nations Sustainable Development goal #7 – affordable and clean energy, the concept of reversible reactive flow (N<sub>2</sub>O<sub>4</sub>/NO<sub>2</sub>) inside ribbed channel is proposed for low-temperature waste heat recovery. Quasi direct numerical simulations are performed to reveal the relationship between flow, heat/mass transfer, and chemical characteristics with different rib inclined angles (90° and 45°). The analyses indicate that the reaction of N<sub>2</sub>O<sub>4</sub> ⇌ 2NO<sub>2</sub> has limited influence on flow patterns inside the ribbed channel, but intensifies the heat transfer considerably. For the 90° reactive case, the enhancement of Nusselt number reaches 112.7 % when Reynolds number is 2000. Although non-equilibrium thermal-chemical phenomenon is observed by instantaneous snapshots, time-averaged results show that the forward endothermic reaction is concentrated close to the heated wall. The flow structures transport fluid pocket consisting of “overheated” gas and triggers local backward exothermic reaction, which decreases the thickness of thermal boundary layer and thereby intensifies the overall heat transfer. For the 45° inclined reactive case, a flow circulation at local equilibrium between heat release and absorption is formed by the rib-induced large-scale vortices. The comprehensive thermal performance is further improved by 24.6 % compared to the 90° reactive case, which attributes to higher Nusselt number and lower friction loss.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126820"},"PeriodicalIF":5.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437872","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

Numerical simulation of heat and mass transfer in novel stepped structure friction stir welding of Ti/Al dissimilar alloys

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2025-02-18 DOI: 10.1016/j.ijheatmasstransfer.2025.126803

Xiankun Zhang , Lei Shi , Hengyu Luo , Chuansong Wu , Sergey Mironov

Friction stir welding (FSW) is one of the most suitable joining methods for Ti/Al dissimilar welding. Understanding and optimizing the heat and mass transfer behavior of Ti/Al dissimilar FSW is crucial for enhancing the mechanical properties of the joints. In this work, a novel stepped structure friction stir welding (SFSW) was proposed to optimize heat and mass transfer for simultaneously improving mechanical properties and welding efficiency. A validated multi-phase numerical model for SFSW of Ti/Al dissimilar alloy was developed using CFD in cooperation with the VOF method. Through numerical modelling and experimental analysis, the influence mechanism of the novel stepped structure on the heat and mass transfer, as well as the resulting microstructure at the weld root was revealed. The stepped structure leads to an increase in temperature at the weld root by approximately 17 K, significantly improving the heat and mass transfer behavior at the weld root. The SFSW approach significantly raises the temperature and strain rate, promoting metallurgical bonding in the Ti/Al interface. It is concluded that the temperature rise caused by the stepped structure is not limited to a specific region, but rather the entire stepped structure as a whole experiences the temperature increase. The stepped structure supports Al adhesion without altering IMCs distribution. By increasing welding speed from 50 to 80 mm/min, SFSW achieves a 60 % boost in welding efficiency, with ultimate tensile strength reaching 320.4 MPa, an 18.4 % improvement over conventional FSW. In summary, the stepped structure is crucial in promoting metallurgical bonding and optimizing heat and mass transfer.

{"title":"Numerical simulation of heat and mass transfer in novel stepped structure friction stir welding of Ti/Al dissimilar alloys","authors":"Xiankun Zhang , Lei Shi , Hengyu Luo , Chuansong Wu , Sergey Mironov","doi":"10.1016/j.ijheatmasstransfer.2025.126803","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126803","url":null,"abstract":"<div><div>Friction stir welding (FSW) is one of the most suitable joining methods for Ti/Al dissimilar welding. Understanding and optimizing the heat and mass transfer behavior of Ti/Al dissimilar FSW is crucial for enhancing the mechanical properties of the joints. In this work, a novel stepped structure friction stir welding (SFSW) was proposed to optimize heat and mass transfer for simultaneously improving mechanical properties and welding efficiency. A validated multi-phase numerical model for SFSW of Ti/Al dissimilar alloy was developed using CFD in cooperation with the VOF method. Through numerical modelling and experimental analysis, the influence mechanism of the novel stepped structure on the heat and mass transfer, as well as the resulting microstructure at the weld root was revealed. The stepped structure leads to an increase in temperature at the weld root by approximately 17 K, significantly improving the heat and mass transfer behavior at the weld root. The SFSW approach significantly raises the temperature and strain rate, promoting metallurgical bonding in the Ti/Al interface. It is concluded that the temperature rise caused by the stepped structure is not limited to a specific region, but rather the entire stepped structure as a whole experiences the temperature increase. The stepped structure supports Al adhesion without altering IMCs distribution. By increasing welding speed from 50 to 80 mm/min, SFSW achieves a 60 % boost in welding efficiency, with ultimate tensile strength reaching 320.4 MPa, an 18.4 % improvement over conventional FSW. In summary, the stepped structure is crucial in promoting metallurgical bonding and optimizing heat and mass transfer.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126803"},"PeriodicalIF":5.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430311","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 simulation research on the dynamic behavior of arc and bubble in ultrasonic frequency pulse current-assisted underwater wet flux cored arc welding

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2025-02-18 DOI: 10.1016/j.ijheatmasstransfer.2025.126853

Xuefei Cui , Ji Chen , Tao Zheng , Hao Su , Shengli Li , Chuansong Wu

In this study, a three-dimensional numerical model is established to investigate the dynamic behavior of the arc and bubble in ultrasonic frequency pulse current-assisted underwater wet flux cored arc welding (UFPC-UWFCAW). The aim is to deepen the understanding of the interaction between the arc and bubble in UFPC-UWFCAW process and evaluate its impact on welding quality. The mathematical model account for the effects of UFPC from both microscale and macroscale perspectives. On the one hand, a microscopic model of plasma under a non-equilibrium state is established to analyze the influence of UFPC on the thermophysical properties of plasma. This analysis reveals that UFPC influenced the plasma thermophysical parameters by altering the number density and velocity distribution function of particles in the plasma. On the other hand, the ultrasonic field excited by UFPC is added to the model as a momentum source term to investigate the influence of UFPC on the heat transfer and fluid flow process of the arc and bubble. To explore the effect of UFPC on the behavior of the arc and bubble, a comparison is conducted between conventional underwater wet flux cored arc welding (C-UWFCAW) and UFPC-UWFCAW. The simulation results demonstrate that UFPC effectively control the arc shape and bubble behavior, reducing instability during the welding process and improving the weld quality. This optimization effect is attributed to the high-frequency characteristics of UFPC, allowing for better control over the arc's heat input and affecting the bubble's growth, necking, and separation processes. The research provides a new theoretical basis for optimizing UFPC-UWFCAW and offers guidance for enhancing the welding process in practical industrial applications.

{"title":"Experimental and simulation research on the dynamic behavior of arc and bubble in ultrasonic frequency pulse current-assisted underwater wet flux cored arc welding","authors":"Xuefei Cui , Ji Chen , Tao Zheng , Hao Su , Shengli Li , Chuansong Wu","doi":"10.1016/j.ijheatmasstransfer.2025.126853","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126853","url":null,"abstract":"<div><div>In this study, a three-dimensional numerical model is established to investigate the dynamic behavior of the arc and bubble in ultrasonic frequency pulse current-assisted underwater wet flux cored arc welding (UFPC-UWFCAW). The aim is to deepen the understanding of the interaction between the arc and bubble in UFPC-UWFCAW process and evaluate its impact on welding quality. The mathematical model account for the effects of UFPC from both microscale and macroscale perspectives. On the one hand, a microscopic model of plasma under a non-equilibrium state is established to analyze the influence of UFPC on the thermophysical properties of plasma. This analysis reveals that UFPC influenced the plasma thermophysical parameters by altering the number density and velocity distribution function of particles in the plasma. On the other hand, the ultrasonic field excited by UFPC is added to the model as a momentum source term to investigate the influence of UFPC on the heat transfer and fluid flow process of the arc and bubble. To explore the effect of UFPC on the behavior of the arc and bubble, a comparison is conducted between conventional underwater wet flux cored arc welding (C-UWFCAW) and UFPC-UWFCAW. The simulation results demonstrate that UFPC effectively control the arc shape and bubble behavior, reducing instability during the welding process and improving the weld quality. This optimization effect is attributed to the high-frequency characteristics of UFPC, allowing for better control over the arc's heat input and affecting the bubble's growth, necking, and separation processes. The research provides a new theoretical basis for optimizing UFPC-UWFCAW and offers guidance for enhancing the welding process in practical industrial applications.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126853"},"PeriodicalIF":5.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430313","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

Research of structure and performance on passive cooling heat sink in TEG waste heat recovery system based on topology optimization

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2025-02-17 DOI: 10.1016/j.ijheatmasstransfer.2025.126795

Liyao Xie , Zhaowei He , Yulong Zhao , Domagoj Vulin

This study employs topology optimization techniques to enhance the structural design and performance of passive cooling heat sinks within thermoelectric generator (TEG) waste heat recovery systems. The topology optimization model aims to minimize the temperature on the heat sink's bottom surface and different fin structures are obtained by altering the Grashof number (Gr). The results show that, at low Gr numbers, fins are elongated and multi-branched, enhancing thermal conduction. Conversely, at high Gr numbers, fins are shorter with fewer branches, relying mainly on natural convection. Topology optimization markedly improves the thermoelectric performance of heat sinks. Compared to conventional straight-fin designs, the optimized heat sink increases the temperature differential by 8.8 %, boosts system output power by 20.1 %, and enhances thermoelectric conversion efficiency by 10.7 %, all while reducing material usage by 55.1 %. The study reveals that different heat sink configurations significantly affect heat transfer and fluid flow within TEG systems. Topology-optimized heat sinks exhibit superior temperature distribution and flow field optimization, though they may introduce increased local resistance.

{"title":"Research of structure and performance on passive cooling heat sink in TEG waste heat recovery system based on topology optimization","authors":"Liyao Xie , Zhaowei He , Yulong Zhao , Domagoj Vulin","doi":"10.1016/j.ijheatmasstransfer.2025.126795","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126795","url":null,"abstract":"<div><div>This study employs topology optimization techniques to enhance the structural design and performance of passive cooling heat sinks within thermoelectric generator (TEG) waste heat recovery systems. The topology optimization model aims to minimize the temperature on the heat sink's bottom surface and different fin structures are obtained by altering the Grashof number (<em>Gr</em>). The results show that, at low <em>Gr</em> numbers, fins are elongated and multi-branched, enhancing thermal conduction. Conversely, at high <em>Gr</em> numbers, fins are shorter with fewer branches, relying mainly on natural convection. Topology optimization markedly improves the thermoelectric performance of heat sinks. Compared to conventional straight-fin designs, the optimized heat sink increases the temperature differential by 8.8 %, boosts system output power by 20.1 %, and enhances thermoelectric conversion efficiency by 10.7 %, all while reducing material usage by 55.1 %. The study reveals that different heat sink configurations significantly affect heat transfer and fluid flow within TEG systems. Topology-optimized heat sinks exhibit superior temperature distribution and flow field optimization, though they may introduce increased local resistance.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126795"},"PeriodicalIF":5.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430310","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

Determination of Spearman's rank correlation for melt spreading-solidification dynamics through the combination of integrated experiments and Monte Carlo method

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2025-02-17 DOI: 10.1016/j.ijheatmasstransfer.2025.126831

Ryo Yokoyama , Kai Wang , Shunichi Suzuki , Shuichiro Miwa , Koji Okamoto

Molten metal spreading and solidification behaviors are crucial phenomena in various fields. This study employs Spearman's rank correlation to identify the key parameters influencing spreading behaviors through a series of experiments and Monte Carlo simulations. The experiments utilized three different low melting point alloys, systematically varying parameters such as water level, subcooling, superheating, and jet velocity, among others. The results revealed that the spreading behaviors can be classified into three distinct modes: (1) clear spreading, (2) irregular spreading, and (3) clear sedimentation. These modes are determined by the energy balance between jet inertia and solidification.

Dimensionless analyses were conducted to investigate the spread areas and thicknesses. The findings demonstrated that thickness increases exponentially with decreasing the dimensionless volume while the spread area decreases due to enhanced cooling efficiency. Additionally, an empirical dimensionless correlations were developed to predict the spread area and thickness based on the interplay between jet-driven inertial forces and solidification. This correlation indicates that the transition between spreading and sedimentation occurs within a threshold range of 0.1 to 0.3. This threshold corresponds to the solid fraction at which the melt immobilizes as the dynamic viscosity sharply increases due to cooling.

Finally, Monte Carlo simulations, utilizing a combination of random sampling and Bayesian modeling, were employed to estimate Spearman's rank correlation. The analysis revealed that the critical parameters for spreading are the latent heat of fusion and the superheat of the melt, as these factors significantly impact the melt's ability to maintain fluidity. In contrast, the melting temperature and subcooling were found to predominantly influence sedimentation by accelerating solidification and enhancing cooling efficiency. These results underscore an empirical correlation that is broadly applicable to general melt spreading phenomena, providing a quantitative framework for identifying the key parameters that govern the process.

{"title":"Determination of Spearman's rank correlation for melt spreading-solidification dynamics through the combination of integrated experiments and Monte Carlo method","authors":"Ryo Yokoyama , Kai Wang , Shunichi Suzuki , Shuichiro Miwa , Koji Okamoto","doi":"10.1016/j.ijheatmasstransfer.2025.126831","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126831","url":null,"abstract":"<div><div>Molten metal spreading and solidification behaviors are crucial phenomena in various fields. This study employs Spearman's rank correlation to identify the key parameters influencing spreading behaviors through a series of experiments and Monte Carlo simulations. The experiments utilized three different low melting point alloys, systematically varying parameters such as water level, subcooling, superheating, and jet velocity, among others. The results revealed that the spreading behaviors can be classified into three distinct modes: (1) clear spreading, (2) irregular spreading, and (3) clear sedimentation. These modes are determined by the energy balance between jet inertia and solidification.</div><div>Dimensionless analyses were conducted to investigate the spread areas and thicknesses. The findings demonstrated that thickness increases exponentially with decreasing the dimensionless volume while the spread area decreases due to enhanced cooling efficiency. Additionally, an empirical dimensionless correlations were developed to predict the spread area and thickness based on the interplay between jet-driven inertial forces and solidification. This correlation indicates that the transition between spreading and sedimentation occurs within a threshold range of 0.1 to 0.3. This threshold corresponds to the solid fraction at which the melt immobilizes as the dynamic viscosity sharply increases due to cooling.</div><div>Finally, Monte Carlo simulations, utilizing a combination of random sampling and Bayesian modeling, were employed to estimate Spearman's rank correlation. The analysis revealed that the critical parameters for spreading are the latent heat of fusion and the superheat of the melt, as these factors significantly impact the melt's ability to maintain fluidity. In contrast, the melting temperature and subcooling were found to predominantly influence sedimentation by accelerating solidification and enhancing cooling efficiency. These results underscore an empirical correlation that is broadly applicable to general melt spreading phenomena, providing a quantitative framework for identifying the key parameters that govern the process.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126831"},"PeriodicalIF":5.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421415","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

Design, optimization, and validation of a triply periodic minimal surface based heat exchanger for extreme temperature applications

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2025-02-17 DOI: 10.1016/j.ijheatmasstransfer.2025.126797

Lalith Dharmalingam, Brian O'Malley, James Tancabel, Vikrant Aute

Heat exchanger (HX) innovation offers potential for significant improvements in energy efficiency for a host of applications including but not limited to aviation and power generation cycles. Triply Periodic Minimal Surfaces (TPMS) have received significant attention in recent years due to their incredibly high surface area density, which makes them very attractive from a heat transfer point of view. Recent efforts have largely focused on thermal-hydraulic characterization of the many available TPMS and the testing of small-scale HX prototypes. However, practical implementation remains largely unexplored, partially due to the extreme computational cost associated with accurately simulating these complex structures. In this work, we present the design, simulation, and optimization of a TPMS-HX for high temperature (900 °C) and pressure (25 MPa) applications. Detailed analysis of HX sub-sections is conducted to define the smallest repeatable section which may be used to characterize the thermal-hydraulic performance of the entire HX, enabling rapid design and iteration with significantly reduced computational cost. Compared to preliminary results for a water-to-water experiment, calibrated heat transfer and pressure drop predictions were within ±5 % and ±10 %, respectively. Optimization results show a 10x increase in volumetric power density over the initial design, which is verified against a parametric exhaustive search of the HX design space. It was found that reducing the unit cell hydraulic diameter cell plays the largest role in increasing heat transfer, increasing the surface area density and enabling a more compact and efficient HX.

{"title":"Design, optimization, and validation of a triply periodic minimal surface based heat exchanger for extreme temperature applications","authors":"Lalith Dharmalingam, Brian O'Malley, James Tancabel, Vikrant Aute","doi":"10.1016/j.ijheatmasstransfer.2025.126797","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126797","url":null,"abstract":"<div><div>Heat exchanger (HX) innovation offers potential for significant improvements in energy efficiency for a host of applications including but not limited to aviation and power generation cycles. Triply Periodic Minimal Surfaces (TPMS) have received significant attention in recent years due to their incredibly high surface area density, which makes them very attractive from a heat transfer point of view. Recent efforts have largely focused on thermal-hydraulic characterization of the many available TPMS and the testing of small-scale HX prototypes. However, practical implementation remains largely unexplored, partially due to the extreme computational cost associated with accurately simulating these complex structures. In this work, we present the design, simulation, and optimization of a TPMS-HX for high temperature (900 °C) and pressure (25 MPa) applications. Detailed analysis of HX sub-sections is conducted to define the smallest repeatable section which may be used to characterize the thermal-hydraulic performance of the entire HX, enabling rapid design and iteration with significantly reduced computational cost. Compared to preliminary results for a water-to-water experiment, calibrated heat transfer and pressure drop predictions were within ±5 % and ±10 %, respectively. Optimization results show a 10x increase in volumetric power density over the initial design, which is verified against a parametric exhaustive search of the HX design space. It was found that reducing the unit cell hydraulic diameter cell plays the largest role in increasing heat transfer, increasing the surface area density and enabling a more compact and efficient HX.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126797"},"PeriodicalIF":5.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421414","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

Frosting characteristics on silver iodide (AgI) micro patterned surface under various temperature conditions

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2025-02-16 DOI: 10.1016/j.ijheatmasstransfer.2025.126826

Jinchen Tang, Takao Okabe, Katsuhiko Nishimura, Anna Sciazko, Naoki Shikazono

This study investigates frost growths on a silver iodide (AgI) patterned surface fabricated by a UV-lithography method under various temperature conditions. Effects of surface temperature and AgI micropatterns under both desublimation condition (ambient temperature of 4.5 ± 1 °C and relative humidity of 37 ± 2 %) and condensation frosting condition (ambient temperature of 23.9 ± 2 °C and relative humidity of 25 ± 5 %) are investigated. In addition, characteristic parameters of frost growth such as frost coverage ratio and frost growth rate are analyzed. Results show that frost on AgI micropattern exhibits very different frost shape compared to that on a bare surface. Planer ice crystals form on the AgI micropatterns, which grow horizontally and remain unchanged for 150 min. This study demonstrates that AgI patterns can effectively suppress frost height by promoting horizontal crystal growth, which may provide new insights to control frost local microstructure such as density and tortuosity.

{"title":"Frosting characteristics on silver iodide (AgI) micro patterned surface under various temperature conditions","authors":"Jinchen Tang, Takao Okabe, Katsuhiko Nishimura, Anna Sciazko, Naoki Shikazono","doi":"10.1016/j.ijheatmasstransfer.2025.126826","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126826","url":null,"abstract":"<div><div>This study investigates frost growths on a silver iodide (AgI) patterned surface fabricated by a UV-lithography method under various temperature conditions. Effects of surface temperature and AgI micropatterns under both desublimation condition (ambient temperature of 4.5 ± 1 °C and relative humidity of 37 ± 2 %) and condensation frosting condition (ambient temperature of 23.9 ± 2 °C and relative humidity of 25 ± 5 %) are investigated. In addition, characteristic parameters of frost growth such as frost coverage ratio and frost growth rate are analyzed. Results show that frost on AgI micropattern exhibits very different frost shape compared to that on a bare surface. Planer ice crystals form on the AgI micropatterns, which grow horizontally and remain unchanged for 150 min. This study demonstrates that AgI patterns can effectively suppress frost height by promoting horizontal crystal growth, which may provide new insights to control frost local microstructure such as density and tortuosity.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126826"},"PeriodicalIF":5.0,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421351","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

Accurate identification of ablation dynamics in charring materials using a stepwise inversion scheme

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2025-02-16 DOI: 10.1016/j.ijheatmasstransfer.2025.126810

Yuhang Yin, Tingting Wu, Hongli Ji, Chongcong Tao, Chao Zhang, Jinhao Qiu

This study introduces a novel stepwise inversion method to accurately estimate the ablation state and surface heat flux of charring ablative materials. By dividing the problem into two sequential steps, the method first determines the thickness of the unpyrolyzed material from the bottom surface temperature data and then uses this information to infer the surface heat flux. This approach enhances the precision of heat flux estimation by increasing the sensitivity coefficients, outperforming traditional direct inversion methods. The Helmholtz filter is applied to smooth the identified heat flux, mitigating the impact of measurement errors. Numerical simulations, validated against experimental data, demonstrate the method's superior accuracy and robustness under various thermal loads. Additionally, the study explores the effects of temperature measurement errors and sensor placement depth, providing comprehensive insights into the practical implementation of this method. This innovative approach significantly improves the design and maintenance of thermal protection systems, ensuring greater reliability and safety for spacecraft subjected to severe aerodynamic heating.

{"title":"Accurate identification of ablation dynamics in charring materials using a stepwise inversion scheme","authors":"Yuhang Yin, Tingting Wu, Hongli Ji, Chongcong Tao, Chao Zhang, Jinhao Qiu","doi":"10.1016/j.ijheatmasstransfer.2025.126810","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126810","url":null,"abstract":"<div><div>This study introduces a novel stepwise inversion method to accurately estimate the ablation state and surface heat flux of charring ablative materials. By dividing the problem into two sequential steps, the method first determines the thickness of the unpyrolyzed material from the bottom surface temperature data and then uses this information to infer the surface heat flux. This approach enhances the precision of heat flux estimation by increasing the sensitivity coefficients, outperforming traditional direct inversion methods. The Helmholtz filter is applied to smooth the identified heat flux, mitigating the impact of measurement errors. Numerical simulations, validated against experimental data, demonstrate the method's superior accuracy and robustness under various thermal loads. Additionally, the study explores the effects of temperature measurement errors and sensor placement depth, providing comprehensive insights into the practical implementation of this method. This innovative approach significantly improves the design and maintenance of thermal protection systems, ensuring greater reliability and safety for spacecraft subjected to severe aerodynamic heating.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"242 ","pages":"Article 126810"},"PeriodicalIF":5.0,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421321","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

Splashing of a gasoline-camellia oil droplet impact on thin film-heated wall: Secondary droplets

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2025-02-16 DOI: 10.1016/j.ijheatmasstransfer.2025.126787

Zhiyu Li , Guanqing Wang , Enhua Zheng , Lu Wang , Tao Wang , Jiangrong Xu

Biomass oil has attracted extensive attention due to its carbon neutrality, high energy density, and renewable nature. During its spray combustion, the droplet impacting heated wall surfaces is of paramount significance. Despite extensive research, few studies focused on the splashing behavior of a mixing oil droplet impacting a thin film on a heated wall, particularly on transition regimes and characteristics of secondary droplets. The present work experimentally studied the splashing behavior of a mixing gasoline-camellia oil (GCO) droplet impacting its thin film on heated walls, with a focus on the secondary droplets and their energy ratio. Their kinematic features (detachment time, velocity, splashing angle) were characterized by analyzing the effects of Weber number (We), Ohnesorge number (Oh) and the wall temperature T_w. Their energy ratio was further estimated through the statistical analysis of their counts and diameters. Novel concise correlations for the detachment time and the energy ratio of the secondary droplet were respectively developed by considering We and Oh. The results show that the detachment time is primarily governed by T_w and Oh, with a minimal influence of We. Splashing angle typically ranges from 30°to 50°, while splashing velocity increases with T_w and We. The count of secondary droplets, while influenced by Oh values, increases with We, gradually converging to a constant value for increasing T_w. The energy ratio of the total secondary droplets exhibits a parabolic behavior as a function of the product of We and Oh. The results demonstrate that a 50 % mixture of the camellia oil-gasoline still exhibits good splashing behavior (secondary atomization), while the optimal mixing ratio is about 25 %. These founding get valuable insights into the heat transfer mechanism involved in the impact, gasification and combustion of GCO.

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引用次数: 0

Single-phase-lagging thermoelastic dissipation for cylindrical shell resonator model with initial stress field

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2025-02-16 DOI: 10.1016/j.ijheatmasstransfer.2025.126800

Jung-Hwan Kim

This study investigates thermoelastic damping in a tubular shell model including time delay of heat flux, which is a critical factor for high-performance, high-frequency vibrational structures. Firstly, the equation of motion is established, and the heat equation with finite speed of heat transfer is introduced including thermal moments. Subsequently, the complex eigenfrequency of a thin shell is obtained according to Donnell–Mushtari–Vlasov's assumption. In addition, the effect based on initial stress along the axial direction is further analyzed that can be caused by self-weight, etc. Moreover, the difference between the real part of the complex result and the traditional isothermal frequency provides insight into the accuracy improvement. Then the thermoelastic damping in the terms of a quality factor (Q) is obtained through approximation assumptions. This work demonstrates that incorporating multiple independent parameters allows for more precise predictions for cylindrical shells. Additionally, the investigation shows the potential of this approach to enhance the efficiency and performance in the design of resonator structures under extreme conditions.

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引用次数: 0