Pub Date : 2026-06-01Epub Date: 2026-01-21DOI: 10.1016/j.ijthermalsci.2026.110703
Ping He , Runfa Liu , Ming Yan , Shun Zhu , Bin Yuan , Xinyu Li , Yiwei Fan , Jing Liu
To effectively prevent local overheating and enhance the thermal safety margin during high-rate charging, a liquid cooling plate featuring a bio-inspired channel structure was designed. The thermophysical properties of the battery cells were determined experimentally. The influence of three key structural parameters—length ratio, spiral angle, and width ratio—on the cooling performance was analyzed. The results demonstrated that the optimal heat transfer performance was achieved with a length ratio of 0.75, a spiral angle of 160°, and a width ratio of 0.85. Furthermore, the cooling performance of three typical channel designs (PC, CC, TVC) with identical flow area was compared. Based on the calculated mathematical expectation, the spiral channel design exhibited the best overall cooling performance. Additionally, the impact of varying the inlet and outlet positions of the coolant on the thermal management of the battery module was investigated. The results indicated that placing the inlet and outlet on the same side yielded the most effective cooling. Under this configuration, the maximum temperature of the battery module was 304.84 K, and the average temperature per cell was 302.324 K.
{"title":"Structural optimization and cooling performance study of bionic spiral channel liquid cooling plate","authors":"Ping He , Runfa Liu , Ming Yan , Shun Zhu , Bin Yuan , Xinyu Li , Yiwei Fan , Jing Liu","doi":"10.1016/j.ijthermalsci.2026.110703","DOIUrl":"10.1016/j.ijthermalsci.2026.110703","url":null,"abstract":"<div><div>To effectively prevent local overheating and enhance the thermal safety margin during high-rate charging, a liquid cooling plate featuring a bio-inspired channel structure was designed. The thermophysical properties of the battery cells were determined experimentally. The influence of three key structural parameters—length ratio, spiral angle, and width ratio—on the cooling performance was analyzed. The results demonstrated that the optimal heat transfer performance was achieved with a length ratio of 0.75, a spiral angle of 160°, and a width ratio of 0.85. Furthermore, the cooling performance of three typical channel designs (PC, CC, TVC) with identical flow area was compared. Based on the calculated mathematical expectation, the spiral channel design exhibited the best overall cooling performance. Additionally, the impact of varying the inlet and outlet positions of the coolant on the thermal management of the battery module was investigated. The results indicated that placing the inlet and outlet on the same side yielded the most effective cooling. Under this configuration, the maximum temperature of the battery module was 304.84 K, and the average temperature per cell was 302.324 K.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110703"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023865","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 : 2026-06-01Epub Date: 2026-01-29DOI: 10.1016/j.ijthermalsci.2026.110725
Bowen Yu, Zhiguo Xu
Droplet impingement on high-temperature solid surfaces is fundamental to numerous industrial technologies. While multilayered textured surfaces and electric field modulation are known to enhance evaporation, their coupled effects remain unexplored. In this work, the multilayered bio-inspired surface, designed based on the springtail cuticle reentrant surface and reef cilia, is proposed to regulate evaporation under a uniform electric field. The coupled lattice Boltzmann-immersed boundary method, accounting for multi-physics interactions, is utilized to systematically examine how Jakob number (Ja), flexible filament, electric capillary number, and Weber number affect the droplet evaporation. Results show that flexible filaments enhance evaporation on the bio-inspired surface, and this effect weakens at high Ja without an electric field but remains significant when the electric field is applied. Electric field-induced vortex redistribution (2.45 % peak vorticity increase at Ja = 0.27) and filament deformation (60.15 % increase in time-averaged contact length at Ja = 0.09) jointly enhance evaporation efficiency. The electric field governs evaporation behavior by promoting droplet expansion and inducing instability associated with detachment-contact dynamics: at Ja = 0.09, increasing the electric capillary number from 0.75 to 1.5 and 2.25 shortens the droplet lifetime by 29.25 % and 39.83 %, respectively; the shortening effect is more significant at Ja = 0.18, with reductions of 37.78 % and 43.65 %. The Weber number exhibits different influences on evaporation at low and high Ja, with a non-monotonic response occurring at Ja = 0.09, whereas at higher Ja (0.135–0.225), increasing Weber number shortens the droplet lifetime.
{"title":"Droplet evaporation on multilayered bio-inspired surfaces under a uniform electric field","authors":"Bowen Yu, Zhiguo Xu","doi":"10.1016/j.ijthermalsci.2026.110725","DOIUrl":"10.1016/j.ijthermalsci.2026.110725","url":null,"abstract":"<div><div>Droplet impingement on high-temperature solid surfaces is fundamental to numerous industrial technologies. While multilayered textured surfaces and electric field modulation are known to enhance evaporation, their coupled effects remain unexplored. In this work, the multilayered bio-inspired surface, designed based on the springtail cuticle reentrant surface and reef cilia, is proposed to regulate evaporation under a uniform electric field. The coupled lattice Boltzmann-immersed boundary method, accounting for multi-physics interactions, is utilized to systematically examine how Jakob number (<em>Ja</em>), flexible filament, electric capillary number, and Weber number affect the droplet evaporation. Results show that flexible filaments enhance evaporation on the bio-inspired surface, and this effect weakens at high <em>Ja</em> without an electric field but remains significant when the electric field is applied. Electric field-induced vortex redistribution (2.45 % peak vorticity increase at <em>Ja</em> = 0.27) and filament deformation (60.15 % increase in time-averaged contact length at <em>Ja</em> = 0.09) jointly enhance evaporation efficiency. The electric field governs evaporation behavior by promoting droplet expansion and inducing instability associated with detachment-contact dynamics: at <em>Ja</em> = 0.09, increasing the electric capillary number from 0.75 to 1.5 and 2.25 shortens the droplet lifetime by 29.25 % and 39.83 %, respectively; the shortening effect is more significant at <em>Ja</em> = 0.18, with reductions of 37.78 % and 43.65 %. The Weber number exhibits different influences on evaporation at low and high <em>Ja</em>, with a non-monotonic response occurring at <em>Ja</em> = 0.09, whereas at higher <em>Ja</em> (0.135–0.225), increasing Weber number shortens the droplet lifetime.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110725"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074470","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 : 2026-06-01Epub Date: 2026-01-30DOI: 10.1016/j.ijthermalsci.2026.110731
Chuanyu Song , Bing Yang , Qi Chen , Shengxiang Wang , Hongyu Zheng
It is proved that the introduction of an interlayer into typical heterostructures can effectively improve the interfacial thermal conductance (ITC) in semiconductor chips. Thus, structure changes of the amorphous carbon (a-C) interlayer caused by the thickness and laser shock duration and related effect on the ITC at the Cu/a-C/3C-SiC heterointerface are investigated in depth by non-equilibrium molecular dynamics, simulated magnetron sputtering, vacuum annealing and laser shock. As the increase of the thicknesses, the ITCs significantly increase first, and then decrease slowly. Notably, a thickness of 0.5 nm increases the ITC by a factor of 3.49. The enhancement mechanism stems from the fact that the introduction of all a-C layers enhances the phonon density of states (PDOS) at 13–21 THz, activates high-frequency phonons at 35–65 THz, reduces the phonon mismatch between Cu and 3C-SiC. However, a further enlargement in thickness increases the amorphous structure, decreases the number of phonons in the ranges of 0–9 THz and 22–29 THz, weakens the phonon coupling at the a-C/3C-SiC sub-interface, ultimately, the ITCs reduce accordingly. Additionally, with the increase of the laser shock durations on the a-C layer, the ITCs show a gradual decrease, with the maximum decrease of 11.55 %. This phenomenon originates from the situation that laser shock decreases the surface roughness of the a-C and the effective contact area at the interfaces, reduces the interfacial van der Waals interactions, attenuates the phonon matching at the Cu/a-C sub-interface. The above analysis provides important reference value for thermal management of GaN-based power chips.
研究证明，在典型异质结构中引入中间层可以有效地提高半导体芯片的界面热导率。为此，采用非平衡分子动力学、模拟磁控溅射、真空退火和激光冲击等方法，深入研究了非晶碳（a-C）层厚度和激光冲击时间对Cu/a-C/3C-SiC异质界面处非晶碳（a-C）层结构的影响及其对ITC的影响。随着厚度的增加，ITCs先显著增加，后缓慢降低。值得注意的是，0.5 nm的厚度使ITC增加了3.49倍。这种增强机制源于全a-C层的引入增强了13-21 THz声子态密度（PDOS），激活了35-65 THz的高频声子，减少了Cu和3C-SiC之间的声子失配。然而，厚度的进一步增加会增加非晶结构，减少0-9 THz和22-29 THz范围内的声子数量，减弱a- c /3C-SiC子界面处的声子耦合，最终导致ITCs相应降低。此外，随着激光冲击时间的增加，a- c层的ITCs逐渐减小，最大降幅为11.55%。这一现象源于激光冲击降低了a-C表面粗糙度和界面有效接触面积，降低了界面范德华相互作用，减弱了Cu/a-C子界面声子匹配。以上分析为gan基功率芯片的热管理提供了重要的参考价值。
{"title":"The regulation mechanism of heat transport at Cu/a-C/3C-SiC heterointerface by interlayer thickness and laser shock","authors":"Chuanyu Song , Bing Yang , Qi Chen , Shengxiang Wang , Hongyu Zheng","doi":"10.1016/j.ijthermalsci.2026.110731","DOIUrl":"10.1016/j.ijthermalsci.2026.110731","url":null,"abstract":"<div><div>It is proved that the introduction of an interlayer into typical heterostructures can effectively improve the interfacial thermal conductance (ITC) in semiconductor chips. Thus, structure changes of the amorphous carbon (a-C) interlayer caused by the thickness and laser shock duration and related effect on the ITC at the Cu/a-C/3C-SiC heterointerface are investigated in depth by non-equilibrium molecular dynamics, simulated magnetron sputtering, vacuum annealing and laser shock. As the increase of the thicknesses, the ITCs significantly increase first, and then decrease slowly. Notably, a thickness of 0.5 nm increases the ITC by a factor of 3.49. The enhancement mechanism stems from the fact that the introduction of all a-C layers enhances the phonon density of states (PDOS) at 13–21 THz, activates high-frequency phonons at 35–65 THz, reduces the phonon mismatch between Cu and 3C-SiC. However, a further enlargement in thickness increases the amorphous structure, decreases the number of phonons in the ranges of 0–9 THz and 22–29 THz, weakens the phonon coupling at the a-C/3C-SiC sub-interface, ultimately, the ITCs reduce accordingly. Additionally, with the increase of the laser shock durations on the a-C layer, the ITCs show a gradual decrease, with the maximum decrease of 11.55 %. This phenomenon originates from the situation that laser shock decreases the surface roughness of the a-C and the effective contact area at the interfaces, reduces the interfacial van der Waals interactions, attenuates the phonon matching at the Cu/a-C sub-interface. The above analysis provides important reference value for thermal management of GaN-based power chips.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110731"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074396","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 : 2026-06-01Epub Date: 2026-01-24DOI: 10.1016/j.ijthermalsci.2026.110718
Jun Zheng (郑俊) , Yibiao Chen (陈一镖) , Nuo Chen (陈诺) , Decai Li (李德才) , Hongming Zhou (周宏明) , Yanjuan Zhang (张艳娟) , Qi Pan (潘琦)
Ferrofluid, valuable for its fluidity and magnetic response, is extensively employed in sealing applications. The sealing capability of ferrofluid is limited by temperature elevation resulting from viscous dissipation, with heat transfer efficiency strongly dependent on thermal conductivity. Although magnetic fields are recognized to modulate the thermal conductivity of ferrofluids, the governing mechanisms under high-field sealing conditions, particularly the impact of excessive aggregation, remain inadequately elucidated. This study employs a multiscale methodology integrating microstructure analysis with macroscopic thermal transport modeling. A modified effective medium theory incorporating magnetic aggregation effects is coupled with microscale heat transfer simulations and experimental validation. Through this framework, the influence of magnetic aggregation on thermal transport under high magnetic fields is systematically examined. The findings indicate that the synergistic action of intense magnetic fields and spatial confinement promotes excessive particle aggregation, giving rise to dense transverse aggregates that ultimately restrict the enhancement of macroscopic thermal conductivity. The elucidated multiscale evolution mechanism offers theoretical insights and technical guidance for advancing thermal management strategies in high-end equipment, precision manufacturing, and energy systems.
{"title":"Correlation between microstructure and macroscopic thermal transport: Mechanism of thermal conductivity variation in ferrofluids in a sealed high magnetic field","authors":"Jun Zheng (郑俊) , Yibiao Chen (陈一镖) , Nuo Chen (陈诺) , Decai Li (李德才) , Hongming Zhou (周宏明) , Yanjuan Zhang (张艳娟) , Qi Pan (潘琦)","doi":"10.1016/j.ijthermalsci.2026.110718","DOIUrl":"10.1016/j.ijthermalsci.2026.110718","url":null,"abstract":"<div><div>Ferrofluid, valuable for its fluidity and magnetic response, is extensively employed in sealing applications. The sealing capability of ferrofluid is limited by temperature elevation resulting from viscous dissipation, with heat transfer efficiency strongly dependent on thermal conductivity. Although magnetic fields are recognized to modulate the thermal conductivity of ferrofluids, the governing mechanisms under high-field sealing conditions, particularly the impact of excessive aggregation, remain inadequately elucidated. This study employs a multiscale methodology integrating microstructure analysis with macroscopic thermal transport modeling. A modified effective medium theory incorporating magnetic aggregation effects is coupled with microscale heat transfer simulations and experimental validation. Through this framework, the influence of magnetic aggregation on thermal transport under high magnetic fields is systematically examined. The findings indicate that the synergistic action of intense magnetic fields and spatial confinement promotes excessive particle aggregation, giving rise to dense transverse aggregates that ultimately restrict the enhancement of macroscopic thermal conductivity. The elucidated multiscale evolution mechanism offers theoretical insights and technical guidance for advancing thermal management strategies in high-end equipment, precision manufacturing, and energy systems.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110718"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074471","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 : 2026-06-01Epub Date: 2026-01-16DOI: 10.1016/j.ijthermalsci.2026.110696
Linfang Fang , Tao Yang , Qingyu Yang , Fuyong Su , Zhiping Yuan , Jun Shen
This paper presents a simulation-based investigation on the thermal behavior of an industrial-scale composite masonry ladle, incorporating with a conventional joint pattern. A three-dimensional model is developed to illustrate the impact of high-temperature loads, material discontinuities, and closed-end effects on the thermo-mechanical performance of the ladle. The study investigates the effects of thermal expansion and friction between masonry units influence stress distribution. The analysis of four joint configurations is fully analyzed, focusing on the open or closed states of both horizontal and vertical joints. The findings indicate that an increased friction coefficient changes the main region of shell deformation. The hoop compressive stress predominantly influences slag line safety, limiting the stress reduction achieved by horizontal joints. Staggered vertical joints along the ladle's circumference effectively mitigate hoop stress and reduce the risk of stress concentration and structural collapse. The microscopic model more accurately represents the thermodynamic behavior in the masonry structure by accounting for material discontinuities, thereby offering a significant theoretical foundation for the optimization of masonry design.
{"title":"Microscopic modeling of thermal coupling in composite refractory masonry ladle with different joint configurations","authors":"Linfang Fang , Tao Yang , Qingyu Yang , Fuyong Su , Zhiping Yuan , Jun Shen","doi":"10.1016/j.ijthermalsci.2026.110696","DOIUrl":"10.1016/j.ijthermalsci.2026.110696","url":null,"abstract":"<div><div>This paper presents a simulation-based investigation on the thermal behavior of an industrial-scale composite masonry ladle, incorporating with a conventional joint pattern. A three-dimensional model is developed to illustrate the impact of high-temperature loads, material discontinuities, and closed-end effects on the thermo-mechanical performance of the ladle. The study investigates the effects of thermal expansion and friction between masonry units influence stress distribution. The analysis of four joint configurations is fully analyzed, focusing on the open or closed states of both horizontal and vertical joints. The findings indicate that an increased friction coefficient changes the main region of shell deformation. The hoop compressive stress predominantly influences slag line safety, limiting the stress reduction achieved by horizontal joints. Staggered vertical joints along the ladle's circumference effectively mitigate hoop stress and reduce the risk of stress concentration and structural collapse. The microscopic model more accurately represents the thermodynamic behavior in the masonry structure by accounting for material discontinuities, thereby offering a significant theoretical foundation for the optimization of masonry design.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110696"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974798","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 : 2026-06-01Epub Date: 2026-01-15DOI: 10.1016/j.ijthermalsci.2026.110698
Qingjun Wang , Yu Chen , Feilong Dou , Yaheng Song , Yufeng Wang
Artificial neural networks are promising for predicting highly nonlinear characteristics of convective heat transfer. Dimensionless and parametric networks are two strategies for supercritical fluid heat transfer prediction, yet their relative accuracy and extrapolation performance with few samples remain unclear. This study obtained a training sample dataset containing 410 sets of data and an extrapolation test dataset containing 940 sets of data of n-decane under supercritical pressure via experiments and calculations. Two corresponding networks were constructed and trained using the sample data, and wall temperature from the dimensionless network was obtained by a surface-intersection method. Results show that in the training sample dataset, both networks show similar errors, while the dimensionless network better captures the characteristics of heat-transfer deterioration. In the extrapolation test dataset, the dimensionless network demonstrates higher accuracy, while the parametric network yields unreasonable predictions in which the predicted wall temperature is lower than the bulk fluid temperature. The reason is that the dimensionless network leverages prior knowledge about the correlation of dimensionless number groups. By directly learning dimensionless variables strongly associated with thermophysical properties, it reduces the degree of nonlinearity in its structure. In contrast, although the parametric network has a simpler structure, it conceals the nonlinear relationships of thermophysical properties and the implicit relationships between wall temperature and other variables. This makes it difficult to extract sufficient information from a small number of samples. This research provides insights into the differences in the extrapolation capability of different artificial neural networks when faced with a limited sample size.
{"title":"Study on the extrapolability of artificial neural network for predicting convective heat transfer of supercritical fluid based on a small number of samples","authors":"Qingjun Wang , Yu Chen , Feilong Dou , Yaheng Song , Yufeng Wang","doi":"10.1016/j.ijthermalsci.2026.110698","DOIUrl":"10.1016/j.ijthermalsci.2026.110698","url":null,"abstract":"<div><div>Artificial neural networks are promising for predicting highly nonlinear characteristics of convective heat transfer. Dimensionless and parametric networks are two strategies for supercritical fluid heat transfer prediction, yet their relative accuracy and extrapolation performance with few samples remain unclear. This study obtained a training sample dataset containing 410 sets of data and an extrapolation test dataset containing 940 sets of data of n-decane under supercritical pressure via experiments and calculations. Two corresponding networks were constructed and trained using the sample data, and wall temperature from the dimensionless network was obtained by a surface-intersection method. Results show that in the training sample dataset, both networks show similar errors, while the dimensionless network better captures the characteristics of heat-transfer deterioration. In the extrapolation test dataset, the dimensionless network demonstrates higher accuracy, while the parametric network yields unreasonable predictions in which the predicted wall temperature is lower than the bulk fluid temperature. The reason is that the dimensionless network leverages prior knowledge about the correlation of dimensionless number groups. By directly learning dimensionless variables strongly associated with thermophysical properties, it reduces the degree of nonlinearity in its structure. In contrast, although the parametric network has a simpler structure, it conceals the nonlinear relationships of thermophysical properties and the implicit relationships between wall temperature and other variables. This makes it difficult to extract sufficient information from a small number of samples. This research provides insights into the differences in the extrapolation capability of different artificial neural networks when faced with a limited sample size.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110698"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974802","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}
As the heat flux of data center chips surpasses 1000 W/cm2, traditional air cooling (limited to 37 W/cm2) and microchannel cooling technologies struggle to meet the efficient heat dissipation demands of next-generation chips due to significant chip temperature differences and thermal stress. While two-phase immersion cooling holds substantial potential, its pool boiling critical heat flux (CHF) and heat transfer coefficient (HTC) require further improvement. To address high-heat-flux chip cooling bottlenecks, this paper proposes synergistically integrating micro heat pipe arrays (MHPA) with immersion phase change cooling (IPCC) to create a staged heat dissipation strategy. A visual experimental system was established using HFE-7100 as the working fluid to systematically investigate boiling heat transfer characteristics and thermal resistance evolution. Experimental results demonstrate that this MHPA-IPCC structure achieves a critical heat flux of 207.6W/cm2, representing a 739.29 % increase over IPCC alone, with a maximum heat transfer coefficient of 4.49 W/(cm2·K), a 219 % improvement, significantly pushing the current limits of heat dissipation. Visual observations revealed the evolution process from natural convection, through nucleate boiling, to film boiling. At a heat flux of 188.3 W/cm2, the system stabilizes hotspot temperature at 103.5 °C; however, film boiling at CHF risks temperature exceedance, necessitating mitigation. Thermal resistance analysis shows that the total thermal resistance (Rt) and MHPA thermal resistance (R2) exhibit a three-stage evolutionary pattern with increasing heat flux: during the low heat flux stage, synergistic working fluid circulation and boiling cause thermal resistance to decrease exponentially; in the medium-to-high heat flux range, the decline becomes linear and gradual; converging to a minimum value (Rt = 0.15 °C/W, R2 = 0.468 °C/W) at the critical condition, where the equivalent thermal conductivity of the MHPA reaches 557 W/(m· K). Compared to existing chip cooling technologies like microchannels and loop heat pipes, this solution demonstrates significant advantages in heat dissipation density, thermal resistance, and heat transfer performance, offering an efficient and reliable thermal management solution for high-power chips.
{"title":"Experimental study on the hotspot cooling performance of immersion chips based on micro heat pipe arrays","authors":"Jiaheng Zhao , Zhenhua Quan , Haibo Ren , Yaohua Zhao","doi":"10.1016/j.ijthermalsci.2026.110694","DOIUrl":"10.1016/j.ijthermalsci.2026.110694","url":null,"abstract":"<div><div>As the heat flux of data center chips surpasses 1000 W/cm<sup>2</sup>, traditional air cooling (limited to 37 W/cm<sup>2</sup>) and microchannel cooling technologies struggle to meet the efficient heat dissipation demands of next-generation chips due to significant chip temperature differences and thermal stress. While two-phase immersion cooling holds substantial potential, its pool boiling critical heat flux (CHF) and heat transfer coefficient (HTC) require further improvement. To address high-heat-flux chip cooling bottlenecks, this paper proposes synergistically integrating micro heat pipe arrays (MHPA) with immersion phase change cooling (IPCC) to create a staged heat dissipation strategy. A visual experimental system was established using HFE-7100 as the working fluid to systematically investigate boiling heat transfer characteristics and thermal resistance evolution. Experimental results demonstrate that this MHPA-IPCC structure achieves a critical heat flux of 207.6W/cm<sup>2</sup>, representing a 739.29 % increase over IPCC alone, with a maximum heat transfer coefficient of 4.49 W/(cm<sup>2</sup>·K), a 219 % improvement, significantly pushing the current limits of heat dissipation. Visual observations revealed the evolution process from natural convection, through nucleate boiling, to film boiling. At a heat flux of 188.3 W/cm<sup>2</sup>, the system stabilizes hotspot temperature at 103.5 °C; however, film boiling at CHF risks temperature exceedance, necessitating mitigation. Thermal resistance analysis shows that the total thermal resistance (<em>R</em><sub><em>t</em></sub>) and MHPA thermal resistance (<em>R</em><sub><em>2</em></sub>) exhibit a three-stage evolutionary pattern with increasing heat flux: during the low heat flux stage, synergistic working fluid circulation and boiling cause thermal resistance to decrease exponentially; in the medium-to-high heat flux range, the decline becomes linear and gradual; converging to a minimum value (<em>R</em><sub><em>t</em></sub> = 0.15 °C/W, <em>R</em><sub><em>2</em></sub> = 0.468 °C/W) at the critical condition, where the equivalent thermal conductivity of the MHPA reaches 557 W/(m· K). Compared to existing chip cooling technologies like microchannels and loop heat pipes, this solution demonstrates significant advantages in heat dissipation density, thermal resistance, and heat transfer performance, offering an efficient and reliable thermal management solution for high-power chips.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110694"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974803","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}
This study systematically investigates the flow condensation characteristics of the zeotropic mixture R1234ze(E)/R1336mzz(Z) in horizontal smooth tubes through experimental methods. A sapphire-quartz coaxial visualization heat exchanger was developed to enable simultaneous measurement of heat transfer coefficients (HTCs) and flow patterns. Experimental parameters encompassed tube diameters (8 mm and 2 mm), mass fluxes (100–600 kg/(m2·s)), and bubble-point temperatures (75 °C and 85 °C). Results demonstrated that stratified and annular flows dominated in the macro-channel (8 mm), while intermittent and annular flows prevailed in the mini-channel (2 mm). The modified Breber flow pattern map is suitable for zeotropic mixtures. Heat transfer analysis revealed a positive relationship between condensation HTCs and both mass flux and vapor quality, with limited sensitivity to bubble-point temperature variations. In the macro-channel, all models (Shah, Marinheiro, and Cavallini et al. with the Bell and Ghaly and Silver correction) overpredicted HTCs by 120–300 % under non-annular flow conditions, which is attributable to non-negligible thermal resistance induced by concentration gradients. By incorporating an attenuation factor related to vapor-liquid composition differentials (y1−x1) and Bond number (Bo), a modified heat transfer correlation accounting for non-equilibrium effects was proposed, reducing the total mean absolute relative deviation from over 60 % (in non-annular flow) to 12.2 % for macro- and mini-channels. This work provides valuable insights and a reliable tool for the design of compact condensers in high-temperature heat pumps and organic Rankine cycles using zeotropic mixtures.
{"title":"Study on the flow condensation flow patterns and heat transfer characteristics of low-GWP zeotropic mixture R1234ze(E)/R1336mzz(Z) in macro- and mini-channels","authors":"Chunyu Feng, Cong Guo, Junbin Chen, Sicong Tan, Yuyan Jiang","doi":"10.1016/j.ijthermalsci.2026.110665","DOIUrl":"10.1016/j.ijthermalsci.2026.110665","url":null,"abstract":"<div><div>This study systematically investigates the flow condensation characteristics of the zeotropic mixture R1234ze(E)/R1336mzz(Z) in horizontal smooth tubes through experimental methods. A sapphire-quartz coaxial visualization heat exchanger was developed to enable simultaneous measurement of heat transfer coefficients (HTCs) and flow patterns. Experimental parameters encompassed tube diameters (8 mm and 2 mm), mass fluxes (100–600 kg/(m<sup>2</sup>·s)), and bubble-point temperatures (75 °C and 85 °C). Results demonstrated that stratified and annular flows dominated in the macro-channel (8 mm), while intermittent and annular flows prevailed in the mini-channel (2 mm). The modified Breber flow pattern map is suitable for zeotropic mixtures. Heat transfer analysis revealed a positive relationship between condensation HTCs and both mass flux and vapor quality, with limited sensitivity to bubble-point temperature variations. In the macro-channel, all models (Shah, Marinheiro, and Cavallini et al. with the Bell and Ghaly and Silver correction) overpredicted HTCs by 120–300 % under non-annular flow conditions, which is attributable to non-negligible thermal resistance induced by concentration gradients. By incorporating an attenuation factor related to vapor-liquid composition differentials (<em>y</em><sub><em>1</em></sub>−<em>x</em><sub><em>1</em></sub>) and Bond number (Bo), a modified heat transfer correlation accounting for non-equilibrium effects was proposed, reducing the total mean absolute relative deviation from over 60 % (in non-annular flow) to 12.2 % for macro- and mini-channels. This work provides valuable insights and a reliable tool for the design of compact condensers in high-temperature heat pumps and organic Rankine cycles using zeotropic mixtures.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110665"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975201","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 : 2026-06-01Epub Date: 2026-01-22DOI: 10.1016/j.ijthermalsci.2026.110712
Dongyun Wang , Artem Khalatov , E. Shi-Ju , Igor Borisov , Oleh Stupak , Tetyana Donyk
This paper presents results of experimental study of flow structure and heat transfer in the accelerating swirling flow insight the subsonic conical nozzle. Three different nozzles with inlet angle (24°, 32°, 40°) and module (0.25, 0.4, 0.56) was tested in this work. The swirl flow generator with variable blade width (φw = 45°, n = 3) was installed in front of the nozzle, the short cylindrical pipe (L0/D = 2.33) was between swirl generator and nozzle inlet aimed to avoid the flow angular unevenness. The experimental program was established for incompressible swirling flow (M < 0.30), the inlet Reynolds number ReDin was ranged from 5.3 104 to 1.1 105, the inlet flow temperature in heat transfer experiments was 110–120°C. The new results obtained include the axial and rotational flow speed, turbulence distribution, and local heat transfer development. The tangential flow dominates in the nozzle axial zone with maximum speed value, gradually shifting to the nozzle central area. Since the axial speed grows faster, the swirl flow angle drops down throughout the nozzle space. The nozzle module affects greatly the radial turbulent fluctuations both inside the nozzle and in front of it, making them almost even across the nozzle radius due to acceleration. At a high flow acceleration (m = 0.25) the turbulent fluctuations fall down up to 3–5 % both in the central nozzle area and near its surface. The novel experimental correlations were obtained, including the angular momentum flux and swirl flow number decay, link between local and total swirl flow parameters, radius of zero static pressure excess, local heat transfer growth, and some others. The Nud/Nud0 ratio is maximal at the nozzle entrance, but drops down inside the nozzle. As for the axial flow the maximal heat transfer occurs in the nozzle minimum cross section.
{"title":"Flow structure and heat transfer in subsonic nozzle with initial flow swirl","authors":"Dongyun Wang , Artem Khalatov , E. Shi-Ju , Igor Borisov , Oleh Stupak , Tetyana Donyk","doi":"10.1016/j.ijthermalsci.2026.110712","DOIUrl":"10.1016/j.ijthermalsci.2026.110712","url":null,"abstract":"<div><div>This paper presents results of experimental study of flow structure and heat transfer in the accelerating swirling flow insight the subsonic conical nozzle. Three different nozzles with inlet angle (24°, 32°, 40°) and module (0.25, 0.4, 0.56) was tested in this work. The swirl flow generator with variable blade width (<em>φ</em><sub>w</sub> = 45°, <em>n</em> = 3) was installed in front of the nozzle, the short cylindrical pipe (<em>L</em><sub><em>0</em></sub><em>/D</em> = 2.33) was between swirl generator and nozzle inlet aimed to avoid the flow angular unevenness. The experimental program was established for incompressible swirling flow (<em>M</em> < 0.30), the inlet Reynolds number Re<sub>D</sub> <sub>in</sub> was ranged from 5.3 10<sup>4</sup> to 1.1 10<sup>5</sup>, the inlet flow temperature in heat transfer experiments was 110–120°C. The new results obtained include the axial and rotational flow speed, turbulence distribution, and local heat transfer development. The tangential flow dominates in the nozzle axial zone with maximum speed value, gradually shifting to the nozzle central area. Since the axial speed grows faster, the swirl flow angle drops down throughout the nozzle space. The nozzle module affects greatly the radial turbulent fluctuations both inside the nozzle and in front of it, making them almost even across the nozzle radius due to acceleration. At a high flow acceleration (<em>m</em> = 0.25) the turbulent fluctuations fall down up to 3–5 % both in the central nozzle area and near its surface. The novel experimental correlations were obtained, including the angular momentum flux and swirl flow number decay, link between local and total swirl flow parameters, radius of zero static pressure excess, local heat transfer growth, and some others. The <em>Nu</em><sub>d</sub>/<em>Nu</em><sub>d0</sub> ratio is maximal at the nozzle entrance, but drops down inside the nozzle. As for the axial flow the maximal heat transfer occurs in the nozzle minimum cross section.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110712"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023754","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 : 2026-06-01Epub Date: 2026-01-22DOI: 10.1016/j.ijthermalsci.2026.110717
Wang Wu , Xiangsheng Chen , Hanqing Chen
The brine artificial ground freezing (AGF) method is an effective technique for ground reinforcement. Compared to liquid nitrogen or carbon dioxide AGF methods, its advantages include easier control of frozen curtain, adjustable freezing temperatures, and lower freezing costs. However, when faster freezing speed is required, conventional brine AGF methods, in which brine temperatures are maintained at −20 °C to −30 °C, may not be sufficient. This has led to the development of the −50 °C ultra-low brine AGF method. Yet, when applying −50 °C ultra-low freezing, it remains unclear whether existing heat transfer correlations apply to the Robin boundary condition. Therefore, this study establishes a numerical model coupling a brine-freezing pipe-ground based on the conjugate heat transfer mechanism. A convective heat transfer numerical model is also developed based on existing single-pipe, single-phase forced convection heat transfer correlations. Comparative results show that when the brine temperature is between −20 °C and −30 °C, the convective heat transfer model and the conjugate heat transfer model agree well, with most temperature data differing by less than 0.1 °C. However, under −50 °C ultra-low brine AGF conditions, the discrepancy between the two models becomes significant, exceeding 2.5 °C. Based on computational results and existing heat transfer correlations, an improved heat transfer correlation suitable for −50 °C ultra-low brine AGF is proposed. The improved convective heat transfer correlation enables a more accurate simulation of the temperature field development in the ultra-low brine AGF process. The findings of this study provide a valuable reference for future applications of −50 °C ultra-low brine AGF methods.
{"title":"An improved heat transfer correlation for −50 °C ultra-low brine artificial ground freezing from the perspective of conjugate heat transfer","authors":"Wang Wu , Xiangsheng Chen , Hanqing Chen","doi":"10.1016/j.ijthermalsci.2026.110717","DOIUrl":"10.1016/j.ijthermalsci.2026.110717","url":null,"abstract":"<div><div>The brine artificial ground freezing (AGF) method is an effective technique for ground reinforcement. Compared to liquid nitrogen or carbon dioxide AGF methods, its advantages include easier control of frozen curtain, adjustable freezing temperatures, and lower freezing costs. However, when faster freezing speed is required, conventional brine AGF methods, in which brine temperatures are maintained at −20 °C to −30 °C, may not be sufficient. This has led to the development of the −50 °C ultra-low brine AGF method. Yet, when applying −50 °C ultra-low freezing, it remains unclear whether existing heat transfer correlations apply to the Robin boundary condition. Therefore, this study establishes a numerical model coupling a brine-freezing pipe-ground based on the conjugate heat transfer mechanism. A convective heat transfer numerical model is also developed based on existing single-pipe, single-phase forced convection heat transfer correlations. Comparative results show that when the brine temperature is between −20 °C and −30 °C, the convective heat transfer model and the conjugate heat transfer model agree well, with most temperature data differing by less than 0.1 °C. However, under −50 °C ultra-low brine AGF conditions, the discrepancy between the two models becomes significant, exceeding 2.5 °C. Based on computational results and existing heat transfer correlations, an improved heat transfer correlation suitable for −50 °C ultra-low brine AGF is proposed. The improved convective heat transfer correlation enables a more accurate simulation of the temperature field development in the ultra-low brine AGF process. The findings of this study provide a valuable reference for future applications of −50 °C ultra-low brine AGF methods.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110717"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023755","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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