International Journal of Thermal Sciences最新文献

{"title":"Similarity analysis for reorientation and self-pressurization of cryogenic fluids in on-orbit propellant tanks","authors":"Zhongqi Zuo ,&nbsp;Bin Wang ,&nbsp;Rongrong Lv ,&nbsp;Lige Tong ,&nbsp;Li Wang","doi":"10.1016/j.ijthermalsci.2025.109910","DOIUrl":"10.1016/j.ijthermalsci.2025.109910","url":null,"abstract":"<div><div>Cryogenic propellants are identified as one of the most promising technologies due to their advantages in specific impulses. However, there still exist gaps in the available knowledge of microgravity cryogenic fluid management, particularly on a large scale. In this study, scaling laws for the interface reorientation and self-pressurization conditions are proposed and validated. Accurate scaling for stationary self-pressurization conditions was achieved by adopting <span><math><mrow><mi>F</mi><mi>o</mi></mrow></math></span> and <span><math><mrow><mi>B</mi><mi>o</mi></mrow></math></span> as similarity criteria. For interface reorientation conditions, the pressure is influenced mainly by the rapid condensation on the interface. The time-factor is proposed to decouple the evolution of the interface and the characteristic length. A new scaling law, <span><math><mrow><mi>t</mi><mo>∼</mo><msup><mrow><mi>L</mi></mrow><mrow><mn>1</mn><mo>.</mo><mn>65</mn></mrow></msup></mrow></math></span>, is proposed to improve the interface similarity between the subscale and the prototype models. The new scaling law significantly improved the pressure prediction accuracy in the scaled models, with a maximum pressure deviation of less than 5%. The scaling methods for the on-orbit cryogenic propellant fluids were systematically proposed and examined by drop tower and ground-based experiments. The results provide a theoretical basis for further scaling experimental and numerical studies of on-orbit cryogenic storage.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828591","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":"Dispersion relation and frequency-dependent thermal conductivity of the two-temperature systems","authors":"S.L. Sobolev ,&nbsp;I.V. Kudinov","doi":"10.1016/j.ijthermalsci.2025.109937","DOIUrl":"10.1016/j.ijthermalsci.2025.109937","url":null,"abstract":"<div><div>We investigate analytically the complex-valued dispersion relation for two-temperature systems with coupling. Based on this dispersion relation, we obtain and analyze the real and imaginary parts of the wave number as well as phase velocity and penetration depth. Furthermore, an effective apparent thermal conductivity is introduced, which depends on the frequency of external thermal disturbances due to coupling effects. It is shown that values of thermal conductivity at high frequencies are drastically reduced compared to low frequencies. The onset of the decrease occurs at a frequency threshold of the order of inverse of characteristic time for energy exchange between subsystems (coupling time). At this frequency, the energy exchange between the subsystems reaches its maximum value and the local nonequilibrium (non-Fourier) effects play the most important role. This work establishes a theoretical basis and opens possibilities for controlling and manipulating heat transfer in heterogeneous systems including composite and thermal metamaterials.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109937"},"PeriodicalIF":4.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of porous structure on the thermal and hydraulic features of combined heat sinks with open microchannels and pin-fins","authors":"Yifan Li ,&nbsp;Tianyu Wang ,&nbsp;Congzhe Zhu ,&nbsp;Zhipeng Wang ,&nbsp;Junlan Yang ,&nbsp;Bin Yang","doi":"10.1016/j.ijthermalsci.2025.109933","DOIUrl":"10.1016/j.ijthermalsci.2025.109933","url":null,"abstract":"<div><div>The rapid development of the computing power of data centers, has resulted in a sharp increase of heat generation on electronic chips. The traditional heat sinks cannot remove the ultra-high heat flux effectively. Novel heat sinks with porous structures are developed to cope with serious overtemperature issues to ensure the safe operation of electronic chips. The effect of the position, porosity, and permeability of porous configurations on the thermal and hydrodynamic features is explored and compared with the traditional smooth microchannel (SM) and the open microchannel with solid pin-fins (OM-SPF). Results manifest that the porous structure is conducive to increasing heat transfer area and enlarging flow space. However, its arrangement significantly influences the temperature control ability and thermal transport rate. For the open microchannel with porous pin-fins (OM-PPF), the friction loss is reduced by 57.1 %, but the perturbance effect is much weaker than the solid counterpart. For the open microchannel with porous sidewall ribs (OM-PSR), the Nusselt number is increased by 2.7, 2.2, and 1.6 times, the peak temperature is reduced by 9.5 °C, 5.6 °C, and 2.5 °C compared to the SM, OM-PPF, and OM-SPF at Re = 631. The friction factor of OM-PSR is 55.1 % smaller than the OM-SPF at Re = 131. The synergy effect of the heat transport enhancement by central solid fins and the drag reduction by porous sidewalls in OM-PSR brings a superior overall capability with a total performance index (<em>TPI</em>) of 2.0 at Re = 329. The small porosity and large permeability of porous sidewalls result in a higher Nusselt number, lower friction factor, and better overall efficiency. The OM-PSR with porosity of 0.2 and permeability of 1 × 10⁻⁸ m² obtains the highest <em>TPI</em> of 4.63 at Re = 131, which helps to balance the heat dissipation and pump consumption, demonstrates a great potential for improving the energy efficiency of the cooling system in high-power data centers.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109933"},"PeriodicalIF":4.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143826184","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 investigation of arc and droplet dynamics in local dry underwater welding under varying ambient pressures","authors":"Xuefei Cui ,&nbsp;Ji Chen ,&nbsp;Jingheng Liang ,&nbsp;Hao Su ,&nbsp;Shengli Li ,&nbsp;Chuansong Wu","doi":"10.1016/j.ijthermalsci.2025.109931","DOIUrl":"10.1016/j.ijthermalsci.2025.109931","url":null,"abstract":"<div><div>A comprehensive numerical model was developed to investigate the effects of varying ambient pressures on arc and molten metal behaviors in local dry underwater welding (LDUW). The model accounted for the influence of ambient pressure on the thermophysical properties of plasma (mass density, specific enthalpy, specific heat, electrical conductivity, thermal conductivity, and viscosity), ensuring high accuracy of simulation results. The results revealed that increasing ambient pressure significantly concentrated the arc shape and altered the spatial distribution of metal vapor. This constriction fundamentally modified the arc plasma properties by reducing the effective heat transfer area and intensifying the interactions between plasma and molten metal. Key parameters such as arc temperature, plasma velocity, current density, and electromagnetic force all decreased with increasing ambient pressure, leading to reduced energy input to the weld pool. Furthermore, the increased ambient pressure altered the droplet transfer behavior. Higher ambient pressures reduced the droplet detachment frequency, while increasing droplet size due to the enhanced constriction of the arc and the altered surface tension forces at the plasma-droplet interface. To validate the numerical model, experiments were conducted using high-speed imaging to capture the real-time droplet processes, and the arc temperature distribution wad measured using spectroscopic methods. The experiments results showed excellent agreement with the simulation data, confirming the reliability of the model. This study provides valuable insights into the impact of ambient pressure on LDUW, offering a solid foundation for optimizing welding parameters to improve process efficiency and weld quality under varying high ambient pressure conditions.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109931"},"PeriodicalIF":4.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143826185","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":"Hydrogen diffusion and deflagration characteristics in a closed battery compartment: experimental and numerical simulation investigation","authors":"Jin Lin ,&nbsp;Jia Jia ,&nbsp;Mengke Zhao ,&nbsp;Qian Li ,&nbsp;Shouxiang Lu ,&nbsp;Mingjun Xu ,&nbsp;Wei Li","doi":"10.1016/j.ijthermalsci.2025.109920","DOIUrl":"10.1016/j.ijthermalsci.2025.109920","url":null,"abstract":"<div><div>The hydrogen diffusion and deflagration characteristics in different ignition positions in a closed battery compartment are systematically researched with experimental and numerical simulation methods, analyzing the hydrogen deflagration flame propagation process, flame propagation velocity, deflagration overpressure, and deflagration temperature. The results show that the maximum concentration gradient between the compartment top and compartment bottom is 4.9%. A nearly spherical flame is first formed after ignition, and the fireball expansion process is restricted by the compartment wall surface and gradually deformed to form a finger-shaped flame. The flame propagation velocity increases with time. And the flame front position increases slowly and then rapidly. In addition, the flame propagates upward from the bottom slightly faster than the flame propagates downward. The deflagration overpressure in ignition position S2 (the top corner of the compartment) is higher compared to that in ignition position S1 (the top center of the compartment), which is nearly 476 KPa. The rise to deflagration peak overpressure is faster when the ignition position is at the compartment top than that at the compartment bottom. In addition, the ignition position on the closed space side (ignition position S2∼S4) is more dangerous.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109920"},"PeriodicalIF":4.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828407","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":"Universal temperature model for large-scale outdoor horizontal tubular microalgae photobioreactor plants","authors":"Heyu Zhang ,&nbsp;Zihao Liu ,&nbsp;Yuyang Chen ,&nbsp;Gege Liu ,&nbsp;Hongjia Bai ,&nbsp;Jing Wu","doi":"10.1016/j.ijthermalsci.2025.109921","DOIUrl":"10.1016/j.ijthermalsci.2025.109921","url":null,"abstract":"<div><div>While the broth temperature is crucial for the design, optimal operation and yield assessment of the microalgae photobioreactors (PBRs), no universal temperature model is available for large-scale outdoor fence-type horizontal tubular PBR plants. A temperature model is created as a function of both the static (location, orientation, and reactor geometry) and dynamic (light irradiance, air temperature, wind velocity, and operation) parameters. The mutual shading among the tubes has a significant effect on the broth temperature and is carefully considered. The model is applicable to both single-row and double-row coiled types of PBRs. The broth temperature in a plant consisting of 10 double-row coiled PBRs, each with 2600 L of gas-free cultivation broth, was subsequently predicted using the model. Based on an analysis of the suitability of various climate zones for algae production, subtropical and temperate monsoon climates are identified as favorable regions. Finally, the relative magnitudes of the various heat transfer rates causing the change in broth temperature are compared. The primary factors affecting the broth temperature are solar radiation, air convection and net longwave radiation, and the direct solar radiation captured by the tubular part of the plant is the most substantial contributor.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109921"},"PeriodicalIF":4.9,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820589","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":"Increasing the ultimate elongation of metal shaped-charge jets by their radiation heating in free flight","authors":"S.V. Fedorov,&nbsp;A.V. Attetkov,&nbsp;I.A. Bolotina,&nbsp;A.M. Kharisov","doi":"10.1016/j.ijthermalsci.2025.109930","DOIUrl":"10.1016/j.ijthermalsci.2025.109930","url":null,"abstract":"<div><div>According to experiments, preliminary heating the liner of the shaped charge allows to increase its penetration effect. The reason for this increase is an increase in the ultimate elongation of the formed shaped-charge jet due to thermal softening of its material. The possibility of heating the jet itself in free flight by thermal radiation of a tube located in front of the shaped charge with heat release in tube, provided by the course of a chemical reaction of self-propagating high-temperature synthesis, is considered. The features of heating shaped-charge jets by thermal radiation are investigated on the basis of an analytical solution of one-dimensional axisymmetric problem of nonstationary heat conductivity for a uniformly elongating cylindrical rod. It is shown that radiation heating of copper shaped-charge jets in free flight is possible, until their plastic break up, to a temperature that allows one to expect some increase in the penetrating effect of the jet.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109930"},"PeriodicalIF":4.9,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820590","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 heat transfer and fluid flow of arc-flash phenomenon in DC molded case circuit breakers: Model optimization and structural improvement","authors":"Wei Duan (段薇),&nbsp;Jing Li (李静),&nbsp;Wanrui Gao (高万瑞),&nbsp;Bingjie Shi (史炳杰),&nbsp;Shuxin Liu (刘树鑫),&nbsp;Yundong Cao (曹云东)","doi":"10.1016/j.ijthermalsci.2025.109919","DOIUrl":"10.1016/j.ijthermalsci.2025.109919","url":null,"abstract":"<div><div>With the increase in circuit breaker interrupting capacity, the frequency of arc-flash phenomena under high-current interruptions rises significantly. However, numerical studies on internal arc-flash phenomena in such equipment are still limited, with most research remaining in its early stages. Due to the complexity of the internal environment in DC molded case circuit breakers (DC-MCCBs), multi-field coupling simulations of high-energy plasma arcs present substantial challenges. This study conducts experimental comparisons to investigate the arc motion and arc-flash pattern evolution in DC-MCCBs under a constant driving magnetic field and varying interrupting current levels. Using magnetohydrodynamics (MHD), an improved arc model accounting for Archimedes force (buoyancy) is developed to analyze the fluid flow, mass transfer, and heat transfer mechanisms within the arc-flash phenomenon. Several structural improvements are proposed to address this phenomenon, with experimental validation of the optimizations. The results show that in the arc chamber of the DC-MCCB, the airflow dispersion effect causes a reverse vortex at the bend of the arc runner, weakening the arc's buoyancy. Additionally, the strong Lorentz force causes the high-energy arc in the lower section to be cut off and move too rapidly, impeding heat dissipation, which limits the utilization of the splitter plates. This results in uneven energy distribution of the arc in the splitter plate region and is the primary cause of the arc-flash phenomenon. The improved dual-side air outlets structure can increase the gas flow rate above the arc chamber, maintaining the forward vortex lift and enhancing the utilization of the splitter plates. The improved insulated gas-generating splitter plate structure can limit arc energy accumulation in the lower splitter region, increase arc chamber pressure, and improve the heat transfer coefficient of the medium, thereby reducing arc-flash energy. Through multi-factor, multi-level orthogonal experiments, comprehensive parameter optimization for arc-flash suppression measures is conducted, providing theoretical foundation and guiding value for the redesign of the new structure of DC-MCCB.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109919"},"PeriodicalIF":4.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816641","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":"Heat transfer analysis of natural fiber composites reinforced with waste glass dust: a numerical and experimental study","authors":"Chandra Sekhar Saran,&nbsp;Alok Satapathy","doi":"10.1016/j.ijthermalsci.2025.109925","DOIUrl":"10.1016/j.ijthermalsci.2025.109925","url":null,"abstract":"<div><div>Rising demand for cost effective and light weight thermal insulation, necessitates to use industrial and bio-wastes in polymers to develop such materials. The estimation of their thermal properties are also equally pertinent. In view of this, the present work reports on the utilization of waste glass dust (WGD) as functional fillers in polymer composites reinforced with two different natural fibers like hemp and flax to develope a new class of thermal insulation. A unique one dimensional heat conduction model is developed to numerically estimate the k_eff of such composites using a finite element method based tool with suitable boundary conditions. Sets of hemp-epoxy and flax-epoxy composites of different filler concentrations (0 %–20 % by weight) are then fabricated using hand lay-up route. Thermal properties such as conductivity, coefficient of thermal expansion (CTE) and glass transition temperature (T_g) of the fabricated composites are measured. The numerical model and experimental results in regard to the conductivity are found to be in good agreement. It is also found that the k_eff of epoxy can be reduced up to 0.144 W/m.K, about 25 % by the reinforcement of natural fibers and waste glass dust. Similarly, a maximum reduction of about 34 % in the value of CTE (27.238 × 10⁻⁶/°C) is achieved. T_g is found to improve from 97 °C (epoxy) to 125.43 °C and 127.03 °C for hemp-epoxy and flax-epoxy composites respectively with the addition of the glass dust particles. Armed with reduced conductivity and favourable CTE and T_g, these composites can potentially be used in thermal insulation applications.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109925"},"PeriodicalIF":4.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816643","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":"Development and application on an unsteady measurement method of heat transfer for aero-engine rotating disk cavity with complex thermal boundary conditions","authors":"Xindi Ming ,&nbsp;Gaowen Liu ,&nbsp;Lingjun Zhang ,&nbsp;Ran Chang ,&nbsp;Aqiang Lin","doi":"10.1016/j.ijthermalsci.2025.109907","DOIUrl":"10.1016/j.ijthermalsci.2025.109907","url":null,"abstract":"<div><div>The measurement method of convective heat transfer coefficient is the technical bottlenecks in carrying out the current thermal analysis and refined design of rotating disk cavity. In order to measure the convective heat transfer coefficient of rotating disk with high rotational speed under complex thermal boundary conditions, this paper proposes a new strategy for acquiring convective heat transfer coefficient by combination with experimental data and numerical calculation of unsteady thermal conductivity in the solid domain. The convective heat transfer coefficient is indirectly obtained at the corresponding position by predicting heat flux through the loading of transient temperature field of solid surface measured in the experiment. Moreover, the effects of Fourier number and measurement random errors on the accuracy of the measurement method during unsteady heat transfer are investigated. The results show that the uncertainty of the convective heat transfer coefficient corresponding to the measurement method is less than 8.20 % when the measurement error is considered. Asymmetric flat plate heat transfer experiments are also carried out. The experimental results show that the deviation of the experimental results from the empirical correlation formula in the range of mass flow rate from 200 g/s to 400 g/s is less than 8 %, which proves that the measurement method can accurately measure the convective heat transfer coefficient under the asymmetric thermal boundary conditions. This paper provides a new convective heat transfer coefficient measurement technique for subsequent rotating disk cavity heat transfer experiments under complex thermal boundary conditions.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143814794","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}