International Journal of Thermal Sciences最新文献

{"title":"Optimum pin-fin spacing of branching radial heat sinks under natural convection for LED cooling","authors":"Trailokya Lochan Tripathy,&nbsp;Sukanta Kumar Dash","doi":"10.1016/j.ijthermalsci.2025.109973","DOIUrl":"10.1016/j.ijthermalsci.2025.109973","url":null,"abstract":"<div><div>The performance of Light Emitting Diodes (LEDs) experiences a significant degradation at elevated temperatures due to inefficient heat dissipation. Passive heat sinks, such as fins, are an effective solution for managing the heat generated by LEDs. The design of fins is critical for ensuring high rates of heat removal as well as lower mass. This study conducts a numerical investigation of radial heat sinks with branching pin fins under natural convection. The primary objective is to obtain an optimum design of the branching pin fins. A parametric study is conducted to observe the effect of fin height (15 mm <span><math><mrow><mo>&lt;</mo><mi>H</mi><mo>&lt;</mo></mrow></math></span> 30 mm), fin number (<span><math><mrow><mn>5</mn><mo>&lt;</mo><mi>n</mi><mo>&lt;</mo><mn>20</mn></mrow></math></span>), and pin-fin spacing (<span><math><mrow><mn>2</mn><mspace></mspace><mtext>mm</mtext><mo>&lt;</mo><msub><mi>L</mi><mi>s</mi></msub><mo>&lt;</mo><mn>10</mn><mspace></mspace><mtext>mm</mtext></mrow></math></span>) on the heat transfer performance of the heat sink arrays. A heat transfer enhancement factor based on the thermal resistance and mass of the heat sink is used to calculate the increase in the heat transfer performance of the current design over the branching plate fin radial heat sinks. Due to the branching pin fins, the mass of the heat sinks reduces by 23 %–33 % for fin heights of 15 mm and 30 mm while providing similar thermal performance as branching plate-fin heat sinks. From the current study, an optimum pin-fin spacing of 4 mm yields the lowest mass and thermal resistance among the other pin fin-spacings for fin arrays with <span><math><mrow><mi>n</mi><mo>&gt;</mo><mn>20</mn></mrow></math></span> and <span><math><mrow><mi>H</mi><mo>=</mo><mn>21.3</mn></mrow></math></span> mm.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"215 ","pages":"Article 109973"},"PeriodicalIF":4.9,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929408","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":"On dispersion of solute in a hydromagnetic flow through a channel subject to asymmetric wall temperature and slip velocity","authors":"Susmita Das ,&nbsp;Bijoy Singha Mazumder ,&nbsp;Kajal Kumar Mondal","doi":"10.1016/j.ijthermalsci.2025.109951","DOIUrl":"10.1016/j.ijthermalsci.2025.109951","url":null,"abstract":"&lt;div&gt;&lt;div&gt;With the influence of asymmetric wall temperature and inclined magnetic field under a constant pressure gradient, the present study explores the transport process of solute in a magneto-hydrodynamics (MHD), viscous, incompressible, electrically conducting fluid through a porous channel. The coupled heat and velocity equations are solved to obtain the explicit expressions for the temperature and velocity profiles. The slip velocity has been taken at the lower wall of the channel and the first order boundary absorption is applied at both the channel walls. Aris’s moment method is employed to obtain the first four central moments and the governing time-dependent advection-diffusion equation is solved, using an implicit finite-difference technique. The axial distribution of mean concentration of the solute is determined by the Hermite polynomial representation. For the first time, the various dispersion characteristics are observed for various parameters, such as the absorption parameter (&lt;span&gt;&lt;math&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;), angle of inclined magnetic field (&lt;span&gt;&lt;math&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;), Prandtl number (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), Hartmann number (&lt;span&gt;&lt;math&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;), suction Reynolds number (&lt;span&gt;&lt;math&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;), injection Reynolds number (&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;′&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;), Darcy number (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), Grashof number (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;G&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), Navier slip parameter (&lt;span&gt;&lt;math&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;), thermal radiation parameter (&lt;span&gt;&lt;math&gt;&lt;mi&gt;δ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;) and dispersion time (&lt;span&gt;&lt;math&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;), simultaneously. It is prominent that when &lt;span&gt;&lt;math&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; increases from 0.1 to 0.2, the dispersion of solute increases 28.68% and when it increases from 0.2 to 0.3, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; increases by 22.75%. Conversely, when &lt;span&gt;&lt;math&gt;&lt;mi&gt;δ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; increases from 1 to 2, the dispersion of solute enhances more rapidly by 154.95% and when &lt;span&gt;&lt;math&gt;&lt;mi&gt;δ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; rises from 2 to 3, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; increases 39.33%. It is significant to note that, the amplitude of the mean concentration &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; reduces as &lt;span&gt;&lt;math&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;G&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; enhances. On the other hand, the amplitude of the mean concentration rises as &lt;span&gt;&lt;math&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; reduces. Both experimental and numerical validations are perf","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"215 ","pages":"Article 109951"},"PeriodicalIF":4.9,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929410","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":"Performance improvement of wavy-plate heat exchanger by vortex generators with adjacent-reverse arrangement","authors":"XuanXing Wan ,&nbsp;KeWei Song ,&nbsp;HaoLong Dong ,&nbsp;QingZhi Hou ,&nbsp;Xiang Wu ,&nbsp;AiLing He","doi":"10.1016/j.ijthermalsci.2025.109982","DOIUrl":"10.1016/j.ijthermalsci.2025.109982","url":null,"abstract":"<div><div>The installation of vortex generators on the heat transfer surface is an effective method for enhancing heat transfer. In this study, a novel arrangement of vortex generators with an adjacent-reverse arrangement on the bottom wall is investigated for wavy fin channel. Configurations of vortex generators with different attack angles are numerically compared. Moreover, the performance of the studied arrangement is compared with that of the normal arrangement in the literature. The results indicate that longitudinal vortices generated by vortex generators with an adjacent-reverse arrangement are more effective at disrupting fluid flow and, consequently, heat transfer improvement. The Nusslet number increases and then decreases with the increase in attack angles, with increments occurring every 15° from 15° to 75°. The Nusselt number of the studied wavy channel increases by 16.6 %–40.5 % for various attack angles compared with the smooth wavy channel, while the friction factor only increases by 7.5 %–30.3 %. Through coupled evaluation of heat transfer and pressure loss characteristics, the 60° attack angle demonstrates optimal performance, achieving a maximum thermal performance factor of 1.29. This value represents a 29 % enhancement compared with the smooth wavy channel. Furthermore, the studied configuration achieves a 5.1 % enhancement compared with the normal setup of vortex generators aligned in the same direction as found in the literature.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"215 ","pages":"Article 109982"},"PeriodicalIF":4.9,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143922749","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 simulation of ice slurry fluid flow characteristics and transport capability in the Flat-Sided Oval Pipe","authors":"Omid Tutunchian ,&nbsp;Majid Abbasalizadeh ,&nbsp;Morteza Khalilian ,&nbsp;Iraj Mirzaee ,&nbsp;Ahad Ramezanpour","doi":"10.1016/j.ijthermalsci.2025.109976","DOIUrl":"10.1016/j.ijthermalsci.2025.109976","url":null,"abstract":"<div><div>Ice slurry due to good characteristics such as fluidity and high energy capacity is one of the common methods in Cold Thermal Energy Storage (CTES). In this study, 3D numerical simulations were carried out using the Eulerian-Eulerian multiphase model to investigate the flow pattern, pressure drop, particle distribution, and related factors in the ice slurry flow. These investigations were conducted within both circular and Flat-Sided Oval Pipe (FSOP) cross-sections with L/H (aspect ratio of cross-section) ratios of 1, 2, and 3. Using FSOP compared to a circular cross-section while maintaining the hydraulic diameter leads to an increase in the pipe's wetted area. The study takes into account a 10.3 wt% ethanol-water solution as a carrier fluid and mass fractions of 10 % and 15 % for ice particles. The increase in entrance region and pressure drop are directly related to the L/H ratio. The results of this study show that in the best case, where L/H = 1, when FSOP cross-section compared to a circular pipe, the wetted area (A_w) increased by 63.7 %, while the increase in pressure drop (P_d) was 1.6 % and 1.3 % for ice mass fractions of 10 % and 15 %, respectively. The ratio between these two parameters, A_w/P_d, showed approximately a 61 % increase for 10 % and 15 % ice mass fraction. In the circular cross-section the ice particles tend to accumulate on the upper side of the pipe cross-section and near the wall, while in FSOP, the particles are pushed out of this central region on the two symmetrical sides near the wall. The study shows that the transport capability is directly proportional to the L/H ratio, inlet velocity, and ice mass fraction. The transport capability within the FSOP cross-section compared to the circular pipe, demonstrates about a 75 % improvement.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"215 ","pages":"Article 109976"},"PeriodicalIF":4.9,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929406","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":"Multi-physics coupling-based numerical simulation and optimization of heat pipe cooling systems for sealed switchgear","authors":"Haodong Yu,&nbsp;Pengsen Yang,&nbsp;Hongwang Yao,&nbsp;Haodong Li,&nbsp;Yannan Li,&nbsp;Hanzhong Tao","doi":"10.1016/j.ijthermalsci.2025.109983","DOIUrl":"10.1016/j.ijthermalsci.2025.109983","url":null,"abstract":"<div><div>A multi-physics coupled numerical model was developed to investigate the thermal performance of sealed high-current switchgear integrated with three heat pipe heat exchangers (HEs) under forced convection. The study evaluates the temperature distribution, Reynolds number (<em>Re</em>), Nusselt number (<em>Nu</em>), and heat transfer coefficient (<em>h</em>) across various airflow configurations. Results show that Scheme IV achieves the best thermal performance, with a maximum temperature drop of 16.82 °C and a 15 % increase in cooling efficiency, attributed to the formation of a strong internal circulation and reduced vortex generation. The highest local <em>h</em> value of 21.96 W/m²·K was obtained in Scheme II, while Scheme III exhibited the highest thermal efficiency per unit fan power, with a quality factor (<em>QF</em>) of 2.25. The heat exchanger system also reduced the temperature rise at faulty tulip contacts by up to 95.7 %, demonstrating its effectiveness in mitigating localized overheating. This work provides quantitative insight into convective enhancement and thermal optimization in sealed electrical enclosures, offering practical guidance for advanced heat management design.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"215 ","pages":"Article 109983"},"PeriodicalIF":4.9,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143922747","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":"Oxide nanoadditives as an effective route to thermal refinement of deep eutectic solvents","authors":"Bertrand Jóźwiak ,&nbsp;Grzegorz Dzido","doi":"10.1016/j.ijthermalsci.2025.109980","DOIUrl":"10.1016/j.ijthermalsci.2025.109980","url":null,"abstract":"<div><div>This study explores thermophysical properties of highly concentrated (1–15 wt%) low-cost, easy-to-synthesize, and scalable nanofluids (NFs) based on deep eutectic solvent (low-viscosity choline chloride/ethylene glycol with molar ratio of 1:5) and metal/metalloid oxide nanoparticles (NPs) of different morphology (SiO₂, Al₂O₃, TiO₂, CuO), across various working temperatures, a topic not previously addressed in the literature. The NFs are characterized in terms of stability, nanoscale morphology, thermal properties, and rheological behavior. Applying oxide NPs reduces the costs of the dispersed phase by 50–99.8 % compared to other commercially available nanomaterials. The NPs in NFs form large agglomerates with <em>Z</em>-average hydrodynamic diameter of 112.4–535.7 nm and a polydispersity index of 0.232–0.406. It was found that nanosilica forms the most stable and fully transparent NFs. Thermal conductivity exhibits a linear increase from 1 % to 15 % (up to 0.255 W m⁻¹ K⁻¹ at 25 °C), regardless of NP type and temperature. Specific heat capacity remains high despite the presence of 15 wt% solids (1.979–2.292 kJ kg^–1 K⁻¹ at 23.5 °C). The viscosity augmentation of NFs occurs in the following order of NPs: CuO &lt; TiO₂ &lt; Al₂O₃ &lt; SiO₂. Neat base liquid and 1–10 wt% NFs exhibit Newtonian behavior, while 15 wt% NFs are more complex shear-thinning media.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"215 ","pages":"Article 109980"},"PeriodicalIF":4.9,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916539","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 on the influence of external magnetic field on the thermal field of aluminum-steel MIG welding-brazing via an integrated numerical model","authors":"Jie Xu ,&nbsp;Longjian Zhou ,&nbsp;Yiming Ma ,&nbsp;Ruwei Geng ,&nbsp;Haocheng Wu ,&nbsp;Yu Fan ,&nbsp;Lin Wang","doi":"10.1016/j.ijthermalsci.2025.109981","DOIUrl":"10.1016/j.ijthermalsci.2025.109981","url":null,"abstract":"<div><div>This study investigates the influence of transverse-parallel magnetic fields (TPMF) on the thermal dynamics of aluminum-steel MIG welding-brazing using a three-dimensional fluid-solid coupled numerical model. The model integrates electromagnetic-fluid dynamics of arc plasma and heat transfer in solid workpieces, enabling self-adaptive prediction of arc morphology and thermal cycles under varying TPMF excitation parameters (current: 0–20 A, frequency: 2–30 Hz). Results show that TPMF induces periodic arc oscillation, changing the peak temperatures at the aluminium-steel interface and expanding the heat-affected zone. Optimal parameters (10 A, 10–15 Hz) enhance interfacial wetting and joint quality, whereas excessive parameters (&gt;10 A or &gt;15 Hz) destabilize the arc and hinder metal spreading. Experimental validation confirms the model's accuracy, providing a reliable tool for optimizing TPMF-assisted welding processes.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"215 ","pages":"Article 109981"},"PeriodicalIF":4.9,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143922748","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":"The coupling effects of oxide particle microstructural parameters and atmospheric (temperature, pressure, composition) conditions on thermal transport in powder beds","authors":"Jordan Letessier ,&nbsp;Aïmen E. Gheribi ,&nbsp;Fabrice Rigollet ,&nbsp;Jerôme Vicente ,&nbsp;Jean-Mathieu Vanson ,&nbsp;Nathalie Ehret ,&nbsp;Christelle Duguay ,&nbsp;Jean-Laurent Gardarein","doi":"10.1016/j.ijthermalsci.2025.109945","DOIUrl":"10.1016/j.ijthermalsci.2025.109945","url":null,"abstract":"<div><div>This study investigates the interdependent influence of microstructural parameters and thermodynamic (temperature between 298 K and 473 K, pressure between 0.1 Pa and 3 10⁷ Pa, various gas composition e.g., air, Ar, H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, He, N<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>) conditions of the atmosphere on thermal transport within granular media. To accurately describe the thermal conductivity behavior, we propose an extended analytical model based on the Rombouts’s model (Rombouts et al., 2005). This study investigates three types of microstructures: dense non-cohesive particles, dense and cohesive particles and porous non-cohesive particles. Analysis of the results provides a precise understanding of the influence of these typical microstructure parameters on thermal conductivity. We underscore the pivotal roles of intraparticle porosity in governing the heat transfer transition in the gas phase. A comparative analysis between our model and a percolation model approach reveals a robust correlation between the two formulations. Our findings indicate that an increase in conductance between particles leads to an enhanced thermal coordination within the system, consequently shifting the thermal percolation threshold to higher values (from 0.1 to 0.5).</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"215 ","pages":"Article 109945"},"PeriodicalIF":4.9,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916538","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":"Research on the influence of cross-distance and cross-phase angle on thermodynamic performance of cross wavy channels","authors":"Ruihao Wang,&nbsp;Zongrui Jin,&nbsp;Tianchu Song,&nbsp;Xiaohu Chen,&nbsp;Zhongyi Wang","doi":"10.1016/j.ijthermalsci.2025.109975","DOIUrl":"10.1016/j.ijthermalsci.2025.109975","url":null,"abstract":"<div><div>It is an energy-saving measure for micro gas turbine to recycle waste heat by using recuperator. The cross wavy recuperator is widely used with the compact and efficient characteristics. Although there have been related studies on its geometric size, the influence of cross form on its thermodynamic performance has not been paid attention to. Therefore, this research innovatively studies the influence of two geometric parameters of the cross form on the thermodynamic performance by the numerical simulation. The results show that only changing the cross-distance can increase the Nusselt number by 3.24 % and the comprehensive performance index by 2.09 % maximally. Only changing the cross-phase angle can decrease the channel resistance and increase the comprehensive performance index by 3.77 % maximally. Based on the sample data of two cross parameters, the comprehensive performance index under each working condition is increased averagely by 12.06 %. Moreover, the correlations of Nusselt number and friction factor are obtained. The average calculation errors of the formulas and numerical simulation are 3.75 % (Nusselt number and 2.47 % (friction factor), which proves the accuracy of the correlation formulas and can provide help for the optimization and design of the cross wavy recuperator.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"215 ","pages":"Article 109975"},"PeriodicalIF":4.9,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916540","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":"Fire characteristics of electric vehicles and occupant evacuation: An experiment study of thermal runaway triggered by nail penetration and heating","authors":"Zhenpo Wang ,&nbsp;Tengfeng Jiang ,&nbsp;Peng Liu ,&nbsp;Bin Chen ,&nbsp;Shipeng Ma ,&nbsp;Qing Wang ,&nbsp;Jinghan Zhang","doi":"10.1016/j.ijthermalsci.2025.109978","DOIUrl":"10.1016/j.ijthermalsci.2025.109978","url":null,"abstract":"<div><div>The thermal runaway (TR) of lithium-ion batteries poses a significant risk to the occupants of electric vehicles (EVs) due to the potential for fire. This study investigates the thermal runaway behavior and fire characteristics of electric vehicles triggered by both nail penetration and heating methods. Through a series of experiments, the full process from thermal runaway propagation (TRP) to complete vehicle fire was examined. The study analyzed key aspects such as temperature changes, smoke concentration, flame spread, and thermal radiation throughout the fire development process. The research results indicate that the maximum TR temperatures for the three experiments were 1236 °C, 1050 °C, and 1236 °C, respectively. During the TRP process, heat conduction accounted for only 7 % of the total heat release. Explosions triggered by heating typically occur earlier and are more intense than those triggered by nail penetration. Carbon monoxide and smoke concentrations pose a threat to occupants even before the explosion, with the smoke concentration in Experiment 2 reaching dangerous levels 793 s after TR. The maximum thermal radiation intensities for the three experiments were 69.3 kW/m², 33.3 kW/m², and 59.5 kW/m², respectively. During the fire, thermal radiation contributed to 5 % of the heat release. Despite the small proportion of thermal radiation, rescue personnel would still be exposed to approximately 20 MJ of thermal radiation energy. During the entire fire process, the total heat release from the battery accounts for only a small portion. The main risk of the battery lies in its ability to ignite surrounding combustible materials, leading to large-scale EV fires. The findings of this study provide theoretical insights into the entire process of EV fires triggered by TRP due to nail penetration and heating, offering valuable implications for improving firefighting and rescue guidelines.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"215 ","pages":"Article 109978"},"PeriodicalIF":4.9,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916736","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}