International Journal of Thermal Sciences最新文献_第4页

Study on heat transfer characteristics of film cooling turbine vane with localized thermal barrier coating

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences

Pub Date : 2025-04-09 DOI: 10.1016/j.ijthermalsci.2025.109926

Peng Guan , Chang-Xu Liu , Jia-Ning He , Yan-Ming Liu , Yan-Ting Al , Bo Guan

With the increase in turbine inlet temperature, thermal barrier coating (TBC) has become an effective thermal protection technology. Localized TBC outperforms conventional uniform TBC in addressing localized overheating and can also reduce the manufacturing cost of the vane. The film cooling turbine vane has a complex structure, which makes numerical simulations of the vane with localized TBC challenging. This study employs multiphysics-coupled numerical simulations and experimental investigations to analyze the thermal insulation effects of localized TBC on film cooling turbine vanes. A high-fidelity numerical simulation model of a film cooling vane with localized TBC is established, and the effects of localized TBC on different regions of the film cooling vane are observed. The results show that localized TBC applied to the leading edge, midsection of the pressure side, and trailing edge of the film cooling turbine vane exhibit better thermal protection. The maximum temperature reduction is approximately 221 K. Specifically, the surface temperature at the leading edge decreases by approximately 200 K, at the midsection of the pressure side by 150–200 K, at the trailing edge of the pressure side by 100–150 K, and at the trailing edge of the suction side by 50–100 K. The localized TBC not only provides effective thermal insulation during engine operation but also significantly mitigates the sudden temperature fluctuations on the vane surface after engine shutdown. Furthermore, the numerical simulation method used in this paper shows a calculation error of less than 15 % compared with experimental results, confirming the accuracy of the simulation results.

{"title":"Study on heat transfer characteristics of film cooling turbine vane with localized thermal barrier coating","authors":"Peng Guan , Chang-Xu Liu , Jia-Ning He , Yan-Ming Liu , Yan-Ting Al , Bo Guan","doi":"10.1016/j.ijthermalsci.2025.109926","DOIUrl":"10.1016/j.ijthermalsci.2025.109926","url":null,"abstract":"<div><div>With the increase in turbine inlet temperature, thermal barrier coating (TBC) has become an effective thermal protection technology. Localized TBC outperforms conventional uniform TBC in addressing localized overheating and can also reduce the manufacturing cost of the vane. The film cooling turbine vane has a complex structure, which makes numerical simulations of the vane with localized TBC challenging. This study employs multiphysics-coupled numerical simulations and experimental investigations to analyze the thermal insulation effects of localized TBC on film cooling turbine vanes. A high-fidelity numerical simulation model of a film cooling vane with localized TBC is established, and the effects of localized TBC on different regions of the film cooling vane are observed. The results show that localized TBC applied to the leading edge, midsection of the pressure side, and trailing edge of the film cooling turbine vane exhibit better thermal protection. The maximum temperature reduction is approximately 221 K. Specifically, the surface temperature at the leading edge decreases by approximately 200 K, at the midsection of the pressure side by 150–200 K, at the trailing edge of the pressure side by 100–150 K, and at the trailing edge of the suction side by 50–100 K. The localized TBC not only provides effective thermal insulation during engine operation but also significantly mitigates the sudden temperature fluctuations on the vane surface after engine shutdown. Furthermore, the numerical simulation method used in this paper shows a calculation error of less than 15 % compared with experimental results, confirming the accuracy of the simulation results.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109926"},"PeriodicalIF":4.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of full-scale thermal-hydraulic characteristics of sodium-cooled fast reactor core under steady-state and accident scenarios

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences

Pub Date : 2025-04-08 DOI: 10.1016/j.ijthermalsci.2025.109909

Zhipeng Yang, Jiacheng Yu, Kai Liu, Hanrui Qiu, Mingjun Wang, Wenxi Tian, G.H. Su

Based on the open-source CFD platform OpenFOAM, CorTAF-SFR has been developed to analyze the 3D thermal-hydraulic characteristics of sodium-cooled fast reactor (SFR) fuel rod assemblies using the finite volume method. The code has been validated against the ORNL-FFM2A and SCARLET-II experiments, demonstrating its accuracy in predicting the thermal-hydraulic behavior of fuel rod assemblies under both steady-state and blockage conditions. The tool was further applied to analyze the thermal-hydraulic performance of the China Experimental Fast Reactor (CEFR) under steady-state operation and accident scenarios. Under steady-state conditions, the average coolant outlet temperature deviation from the design values was within 2.0 K, with significant temperature drops observed at the component interface regions. During an overpower accident, peak temperatures of the coolant, cladding surface, and fuel pellet reached 1028.4 K, 1030.6 K, and 1598.9 K, respectively. In the blockage accident, the temperature of the blocked area increased significantly, and the coolant flow rate at about 150 mm downstream of the blocked area returned to the original level. Detailed analysis revealed the thermal-hydraulic behavior changes during the overpower scenario and the mechanisms of flow and temperature field alterations in blocked regions. These findings are crucial for advancing thermal-hydraulic analysis methods for SFR cores and ensuring reactor safety and performance.

{"title":"Analysis of full-scale thermal-hydraulic characteristics of sodium-cooled fast reactor core under steady-state and accident scenarios","authors":"Zhipeng Yang, Jiacheng Yu, Kai Liu, Hanrui Qiu, Mingjun Wang, Wenxi Tian, G.H. Su","doi":"10.1016/j.ijthermalsci.2025.109909","DOIUrl":"10.1016/j.ijthermalsci.2025.109909","url":null,"abstract":"<div><div>Based on the open-source CFD platform OpenFOAM, CorTAF-SFR has been developed to analyze the 3D thermal-hydraulic characteristics of sodium-cooled fast reactor (SFR) fuel rod assemblies using the finite volume method. The code has been validated against the ORNL-FFM2A and SCARLET-II experiments, demonstrating its accuracy in predicting the thermal-hydraulic behavior of fuel rod assemblies under both steady-state and blockage conditions. The tool was further applied to analyze the thermal-hydraulic performance of the China Experimental Fast Reactor (CEFR) under steady-state operation and accident scenarios. Under steady-state conditions, the average coolant outlet temperature deviation from the design values was within 2.0 K, with significant temperature drops observed at the component interface regions. During an overpower accident, peak temperatures of the coolant, cladding surface, and fuel pellet reached 1028.4 K, 1030.6 K, and 1598.9 K, respectively. In the blockage accident, the temperature of the blocked area increased significantly, and the coolant flow rate at about 150 mm downstream of the blocked area returned to the original level. Detailed analysis revealed the thermal-hydraulic behavior changes during the overpower scenario and the mechanisms of flow and temperature field alterations in blocked regions. These findings are crucial for advancing thermal-hydraulic analysis methods for SFR cores and ensuring reactor safety and performance.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigation of enhancing heat transfer in three Kenics static mixer utilizing muti-objective optimization

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences

Pub Date : 2025-04-08 DOI: 10.1016/j.ijthermalsci.2025.109911

Yanfang Yu , Wenlong Qiao , Huibo Meng , Haijun Wan , Wen Sun , Puyu Zhang , Jingyu Guo , Feng Wang

The enhancement of heat transfer efficiency in industrial processes remains a critical technological challenge for achieving optimal energy utilization and minimizing environmental impacts. In light of static mixers efficient heat transfer, this study employs experimental and numerical simulations at Re = 2600 ‒ 17,700 to investigate the influence of various geometric parameters in three Kenics static mixer (TKSM), including elevation angles (α = 0°, 3°, 5°, 7°), deflection angles (θ = 0°, 30°, 60°), and aspect ratios (A_r = 1, 1.25, 1.5). Artificial neural networks and multi-objective genetic algorithms are implemented to predict the geometric structure. Results indicate that the optimal heat transfer performance of TKSM occurs at α = 5° and θ = 60°, demonstrating an improvement of 1.69 %–3.7 % compared to α = 0°; when θ = 0° and α = 7°, the overall heat transfer performance of the α = 7° structure is improved by 6.9 %–11.7 % compared to the unmodified TKSM. Through ANNs modeling, correlations were established between structural parameters, heat transfer performance and fluid resistance, achieving prediction accuracies of 93.84 % and 89.6 % for Nusselt number (Nu) and pressure drop(Δp), respectively. In the Re range of 2600–8800, the optimal structures are: α = 9°–9.6°, θ = 0.2°–0.5°, and A_r range from 1.39 to 1.46. Compared with the initial structure under the same operating conditions, the comprehensive heat transfer performance is improved by 7.69 %–11.58 %. In the Re range of 8800–17700, the optimal structures are: α = 2.2°–7.4°, θ = 18.9°–60° and A_r range from 1.46 to 1.5, the comprehensive heat transfer performance is improved by 7.85 %–9.84 %.

{"title":"Investigation of enhancing heat transfer in three Kenics static mixer utilizing muti-objective optimization","authors":"Yanfang Yu , Wenlong Qiao , Huibo Meng , Haijun Wan , Wen Sun , Puyu Zhang , Jingyu Guo , Feng Wang","doi":"10.1016/j.ijthermalsci.2025.109911","DOIUrl":"10.1016/j.ijthermalsci.2025.109911","url":null,"abstract":"<div><div>The enhancement of heat transfer efficiency in industrial processes remains a critical technological challenge for achieving optimal energy utilization and minimizing environmental impacts. In light of static mixers efficient heat transfer, this study employs experimental and numerical simulations at <em>Re</em> = 2600 ‒ 17,700 to investigate the influence of various geometric parameters in three Kenics static mixer (TKSM), including elevation angles (<em>α</em> = 0°, 3°, 5°, 7°), deflection angles (<em>θ</em> = 0°, 30°, 60°), and aspect ratios (<em>A</em><sub>r</sub> = 1, 1.25, 1.5). Artificial neural networks and multi-objective genetic algorithms are implemented to predict the geometric structure. Results indicate that the optimal heat transfer performance of TKSM occurs at <em>α</em> = 5° and <em>θ</em> = 60°, demonstrating an improvement of 1.69 %–3.7 % compared to <em>α</em> = 0°; when <em>θ</em> = 0° and <em>α</em> = 7°, the overall heat transfer performance of the <em>α</em> = 7° structure is improved by 6.9 %–11.7 % compared to the unmodified TKSM. Through ANNs modeling, correlations were established between structural parameters, heat transfer performance and fluid resistance, achieving prediction accuracies of 93.84 % and 89.6 % for Nusselt number (<em>Nu</em>) and pressure drop(Δ<em>p</em>), respectively. In the <em>Re</em> range of 2600–8800, the optimal structures are: <em>α</em> = 9°–9.6°, <em>θ</em> = 0.2°–0.5°, and <em>A</em><sub>r</sub> range from 1.39 to 1.46. Compared with the initial structure under the same operating conditions, the comprehensive heat transfer performance is improved by 7.69 %–11.58 %. In the <em>Re</em> range of 8800–17700, the optimal structures are: <em>α</em> = 2.2°–7.4°, <em>θ</em> = 18.9°–60° and <em>A</em><sub>r</sub> range from 1.46 to 1.5, the comprehensive heat transfer performance is improved by 7.85 %–9.84 %.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Heat transfer and aerodynamic losses of additively manufactured turbine alloy blades with different surface enhancement post-processing

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences

Pub Date : 2025-04-08 DOI: 10.1016/j.ijthermalsci.2025.109914

Phillip M. Ligrani , Christoph Bueschges , Morgan Tatge , Bernhard Weigand , Chelakara Subramanian , Hallie L. Collopy , Zach Taylor , Jason Sheth , Paul Gradl

With increasing temperatures and pressure ratios, the requirements for rocket engine turbine blades become more demanding. Additive manufacturing (AM) enables production of complex geometries for such an application environment, while using novel alloys, such as GRX-810, an alloy with superior strength and durability at elevated temperatures compared to currently employed alloys. An inherent characteristic of such additively manufactured components is a rough surface texture, which varies depending upon the surface enhancement post processing procedure. With the present investigation, procedures which are considered include as built (AM0 blade), abrasive flow machining (AM5 blade), and chemical polishing in combination with chemical mechanical polishing (AM4 blade). The effects of the resulting surface textures are considered as they affect turbine blade aerodynamic losses, and turbine blade tip surface heat transfer coefficient distributions. To acquire these data, a transonic linear cascade within a transonic/supersonic wind tunnel is utilized, with centrally installed, and additively manufactured GRX-810 turbine blades, which are instrumented for aerodynamic loss and surface heat transfer measurements. Measured wake profile variations for the AM0, AM4, and AM5 blades are a consequence of multiple physical effects and phenomena, with different relative consequences, which depend upon the blade wake location, local blade shape alterations, as well as the character and magnitude of surface roughness. Dimensional heat transfer coefficient values along the tips of the turbine alloy blades are generally larger with the rougher surface textures, which are associated with increased tip gap flow friction, and locally lower tip gap flow Mach numbers.

{"title":"Heat transfer and aerodynamic losses of additively manufactured turbine alloy blades with different surface enhancement post-processing","authors":"Phillip M. Ligrani , Christoph Bueschges , Morgan Tatge , Bernhard Weigand , Chelakara Subramanian , Hallie L. Collopy , Zach Taylor , Jason Sheth , Paul Gradl","doi":"10.1016/j.ijthermalsci.2025.109914","DOIUrl":"10.1016/j.ijthermalsci.2025.109914","url":null,"abstract":"<div><div>With increasing temperatures and pressure ratios, the requirements for rocket engine turbine blades become more demanding. Additive manufacturing (AM) enables production of complex geometries for such an application environment, while using novel alloys, such as GRX-810, an alloy with superior strength and durability at elevated temperatures compared to currently employed alloys. An inherent characteristic of such additively manufactured components is a rough surface texture, which varies depending upon the surface enhancement post processing procedure. With the present investigation, procedures which are considered include as built (AM0 blade), abrasive flow machining (AM5 blade), and chemical polishing in combination with chemical mechanical polishing (AM4 blade). The effects of the resulting surface textures are considered as they affect turbine blade aerodynamic losses, and turbine blade tip surface heat transfer coefficient distributions. To acquire these data, a transonic linear cascade within a transonic/supersonic wind tunnel is utilized, with centrally installed, and additively manufactured GRX-810 turbine blades, which are instrumented for aerodynamic loss and surface heat transfer measurements. Measured wake profile variations for the AM0, AM4, and AM5 blades are a consequence of multiple physical effects and phenomena, with different relative consequences, which depend upon the blade wake location, local blade shape alterations, as well as the character and magnitude of surface roughness. Dimensional heat transfer coefficient values along the tips of the turbine alloy blades are generally larger with the rougher surface textures, which are associated with increased tip gap flow friction, and locally lower tip gap flow Mach numbers.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109914"},"PeriodicalIF":4.9,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Theoretical study of bubble departure and lift-off diameters model for evaporation based on microlayer in flow boiling

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences

Pub Date : 2025-04-08 DOI: 10.1016/j.ijthermalsci.2025.109906

Wu-han Dong, Ming Gao, Zhong-xiang Shen, Meng-yuan Dang, Li-xin Zhang

This study was devoted to the theory of microlayer evaporation and bubble dynamics. In subcooled flowing boiling, a theoretical study of the mechanism of heat and mass transfer in vapor bubbles during boiling heat transfer has been carried out. The forces on mononuclear boiling bubbles during subcooled flow boiling are analyzed. In addition, the effect of microlayer evaporation was considered, and microlayer evaporation force has been introduced. Evaporation of the microlayers as between the bottom of a bubble and the heated wall, evaporation of the layer of superheated liquid around the bubble, the condensation of the vapors at the top of a bubble are taken into account on the basis of the bubble dynamics. The prediction models for bubble forces, departure and lift-off diameters were improved. The influence of force on the bubble under the same working conditions was also investigated. Compared with previous experimental results, it was found that the improved model could forecast the diameters of the bubble departure and bubble lift-off well.

{"title":"Theoretical study of bubble departure and lift-off diameters model for evaporation based on microlayer in flow boiling","authors":"Wu-han Dong, Ming Gao, Zhong-xiang Shen, Meng-yuan Dang, Li-xin Zhang","doi":"10.1016/j.ijthermalsci.2025.109906","DOIUrl":"10.1016/j.ijthermalsci.2025.109906","url":null,"abstract":"<div><div>This study was devoted to the theory of microlayer evaporation and bubble dynamics. In subcooled flowing boiling, a theoretical study of the mechanism of heat and mass transfer in vapor bubbles during boiling heat transfer has been carried out. The forces on mononuclear boiling bubbles during subcooled flow boiling are analyzed. In addition, the effect of microlayer evaporation was considered, and microlayer evaporation force has been introduced. Evaporation of the microlayers as between the bottom of a bubble and the heated wall, evaporation of the layer of superheated liquid around the bubble, the condensation of the vapors at the top of a bubble are taken into account on the basis of the bubble dynamics. The prediction models for bubble forces, departure and lift-off diameters were improved. The influence of force on the bubble under the same working conditions was also investigated. Compared with previous experimental results, it was found that the improved model could forecast the diameters of the bubble departure and bubble lift-off well.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109906"},"PeriodicalIF":4.9,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Combining surface modification of carbon fiber and introduction of phase change capsules to synergistically improve heat dissipation performance of dual-function polymeric composite

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences

Pub Date : 2025-04-07 DOI: 10.1016/j.ijthermalsci.2025.109923

Junpeng Zhou , Yu Zhao , Chi Yin , Zhengguo Zhang , Ziye Ling , Xiaoming Fang

Thermally conductive composites are widely employed for heat dissipation of electronic devices, but they suffer from incompatibility between thermally conductive filler and polymeric matrix and lack of a function to relieve thermal shock. Elucidating the relationship between surface modification of thermally conductive filler and interface thermal resistance to optimize thermal conductivity for thermally conductive composite, along with introducing phase change capsules to craft dual-function composite with both heat conduction and storage properties, is expected to address these issues. Herein, we chose polydopamine (PDA)-modified carbon fiber (CF) as a prototype to elucidate relationship between surface modification and interface thermal resistance within polydimethylsiloxane (PDMS)-based composite. Molecular dynamics simulations suggested that the modification with PDA did decrease the interfacial thermal resistance between CF and PDMS, but the loading of PDA needed to be controlled at an appropriate amount. The highest thermal conductivity was achieved by the CF/PDMS composite containing 20 wt% of the optimal PDA-modified CF, which composite was then combined with paraffin@SiO₂ nanocapsules with different mass fractions to craft dual-function composites. The obtained dual-function composites exhibited enhanced thermal conductivity, increased heat storage capacity and decreased hardness with increasing mass fraction of the nanocapsules, all of which changes are positive factors in affecting heat dissipation performance. When loading the nanocapsules at 15 wt%, the obtained dual-function composite achieved much improved heat dissipation performance, accounting for the contributes of both the surface modification with PDA and the introduction of the nanocapsules.

{"title":"Combining surface modification of carbon fiber and introduction of phase change capsules to synergistically improve heat dissipation performance of dual-function polymeric composite","authors":"Junpeng Zhou , Yu Zhao , Chi Yin , Zhengguo Zhang , Ziye Ling , Xiaoming Fang","doi":"10.1016/j.ijthermalsci.2025.109923","DOIUrl":"10.1016/j.ijthermalsci.2025.109923","url":null,"abstract":"<div><div>Thermally conductive composites are widely employed for heat dissipation of electronic devices, but they suffer from incompatibility between thermally conductive filler and polymeric matrix and lack of a function to relieve thermal shock. Elucidating the relationship between surface modification of thermally conductive filler and interface thermal resistance to optimize thermal conductivity for thermally conductive composite, along with introducing phase change capsules to craft dual-function composite with both heat conduction and storage properties, is expected to address these issues. Herein, we chose polydopamine (PDA)-modified carbon fiber (CF) as a prototype to elucidate relationship between surface modification and interface thermal resistance within polydimethylsiloxane (PDMS)-based composite. Molecular dynamics simulations suggested that the modification with PDA did decrease the interfacial thermal resistance between CF and PDMS, but the loading of PDA needed to be controlled at an appropriate amount. The highest thermal conductivity was achieved by the CF/PDMS composite containing 20 wt% of the optimal PDA-modified CF, which composite was then combined with paraffin@SiO<sub>2</sub> nanocapsules with different mass fractions to craft dual-function composites. The obtained dual-function composites exhibited enhanced thermal conductivity, increased heat storage capacity and decreased hardness with increasing mass fraction of the nanocapsules, all of which changes are positive factors in affecting heat dissipation performance. When loading the nanocapsules at 15 wt%, the obtained dual-function composite achieved much improved heat dissipation performance, accounting for the contributes of both the surface modification with PDA and the introduction of the nanocapsules.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109923"},"PeriodicalIF":4.9,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental and numerical analysis of a novel constructal design for canopy-to-canopy liquid cooling systems

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences

Pub Date : 2025-04-05 DOI: 10.1016/j.ijthermalsci.2025.109918

José Félix Guil-Pedrosa , Luis Miguel García-Gutiérrez , Antonio Soria-Verdugo , Sylvie Lorente

The cooling capacity of canopy-to-canopy flat plates with the coolant inlet and outlet on the same side of the plate was analyzed in detail, both experimentally and numerically. A novel constructal design was proposed to derive the diameter of each branch of canopy-to-canopy configurations. Thanks to the predicted diameter ratios, the new design results in a reduction of the coolant pumping power of 60 % to achieve the same maximum temperature as a traditional configuration with equal diameters in all branches. Four canopy-to-canopy configurations with a number of branches ranging from 2 to 5 were designed based on this innovative constructal approach to optimize the cooling capacity of flat plate systems, keeping the same fluid volume for all of them. The resulting designs were tested experimentally and modelled for steady state and transient cooling operations. A higher number of branches improved the steady state cooling performance under continuous heating, as the 5-branches configuration yielded the lowest maximum and mean temperatures while maintaining similar temperature homogeneity in both experimental measurements and numerical simulations. The maximum deviation between experimental and numerical results was 1.4 °C for both maximum and average temperatures, allowing the validation of the numerical models. For the transient cooling process, the flat plates experienced a progressively faster temperature reduction over time as the number of branches in the design increases, accelerating the cooling process by 14.7 % when increasing the number of branches from 2 to 5. The results show that the 5-branches canopy-to-canopy configuration has an excellent cooling capacity with a limited pressure drop to circulate the coolant.

{"title":"Experimental and numerical analysis of a novel constructal design for canopy-to-canopy liquid cooling systems","authors":"José Félix Guil-Pedrosa , Luis Miguel García-Gutiérrez , Antonio Soria-Verdugo , Sylvie Lorente","doi":"10.1016/j.ijthermalsci.2025.109918","DOIUrl":"10.1016/j.ijthermalsci.2025.109918","url":null,"abstract":"<div><div>The cooling capacity of canopy-to-canopy flat plates with the coolant inlet and outlet on the same side of the plate was analyzed in detail, both experimentally and numerically. A novel constructal design was proposed to derive the diameter of each branch of canopy-to-canopy configurations. Thanks to the predicted diameter ratios, the new design results in a reduction of the coolant pumping power of 60 % to achieve the same maximum temperature as a traditional configuration with equal diameters in all branches. Four canopy-to-canopy configurations with a number of branches ranging from 2 to 5 were designed based on this innovative constructal approach to optimize the cooling capacity of flat plate systems, keeping the same fluid volume for all of them. The resulting designs were tested experimentally and modelled for steady state and transient cooling operations. A higher number of branches improved the steady state cooling performance under continuous heating, as the 5-branches configuration yielded the lowest maximum and mean temperatures while maintaining similar temperature homogeneity in both experimental measurements and numerical simulations. The maximum deviation between experimental and numerical results was 1.4 °C for both maximum and average temperatures, allowing the validation of the numerical models. For the transient cooling process, the flat plates experienced a progressively faster temperature reduction over time as the number of branches in the design increases, accelerating the cooling process by 14.7 % when increasing the number of branches from 2 to 5. The results show that the 5-branches canopy-to-canopy configuration has an excellent cooling capacity with a limited pressure drop to circulate the coolant.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109918"},"PeriodicalIF":4.9,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143777217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Entropy optimization and Prandtl-Eyring non-Newtonian fluid flow with second-order slip conditions past a curved Riga sheet; numerical simulation

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences

Pub Date : 2025-04-04 DOI: 10.1016/j.ijthermalsci.2025.109916

Bilal Ali , Yue-Ting Zhou , Sidra Jubair , Muzammal Hameed Tariq , Abhinav Kumar , Md Irfanul Haque Siddiqui

The non-Newtonian (NN) Prandtl-Eyring fluid (PEF) model can be used to optimize conditions for processing, ensure substance high quality and consistency, and anticipate melted polymer flow behavior. This paper looks into an intriguing feature of irreversibility estimation through NN-PEF flow over a curved Riga surface. The impact of second-order slip conditions, thermal radiation, and exponential heat source/sink are also elaborated. The flow equations of NN-PEF have been reformulated into a dimensionless representation of differential equations (DEs) with an application of similarity conversions. The obtained lowest-order differential equations are numerically solved through the PCM (parametric continuation method). For accuracy of the results, the outcomes are compared to both experimental and theoretical results. The relative percent error between the present findings and the published numerical results at Re = 5000 is 0.71094 %. The rate of heat transfer (W/m²K) enhances from 4238.0724 to 44390.4205 at Re = 1594 to 440. The relative error between published experimental and present results is about 0.0029 % at Re = 440, which ensures the reliability of the proposed model and applied methodology. The velocity field of PEF is significantly boosted with the positive variation in 1st and 2nd order slip parameters. The influence of the Brinkmann number and heat radiation factor is enhanced, while the consequences of the temperature ratio parameter drop the rate of entropy generation in the system.

{"title":"Entropy optimization and Prandtl-Eyring non-Newtonian fluid flow with second-order slip conditions past a curved Riga sheet; numerical simulation","authors":"Bilal Ali , Yue-Ting Zhou , Sidra Jubair , Muzammal Hameed Tariq , Abhinav Kumar , Md Irfanul Haque Siddiqui","doi":"10.1016/j.ijthermalsci.2025.109916","DOIUrl":"10.1016/j.ijthermalsci.2025.109916","url":null,"abstract":"<div><div>The non-Newtonian (NN) Prandtl-Eyring fluid (PEF) model can be used to optimize conditions for processing, ensure substance high quality and consistency, and anticipate melted polymer flow behavior. This paper looks into an intriguing feature of irreversibility estimation through NN-PEF flow over a curved Riga surface. The impact of second-order slip conditions, thermal radiation, and exponential heat source/sink are also elaborated. The flow equations of NN-PEF have been reformulated into a dimensionless representation of differential equations (DEs) with an application of similarity conversions. The obtained lowest-order differential equations are numerically solved through the PCM (parametric continuation method). For accuracy of the results, the outcomes are compared to both experimental and theoretical results. The relative percent error between the present findings and the published numerical results at Re = 5000 is 0.71094 %. The rate of heat transfer (W/m<sup>2</sup>K) enhances from 4238.0724 to 44390.4205 at Re = 1594 to 440. The relative error between published experimental and present results is about 0.0029 % at Re = 440, which ensures the reliability of the proposed model and applied methodology. The velocity field of PEF is significantly boosted with the positive variation in 1st and 2nd order slip parameters. The influence of the Brinkmann number and heat radiation factor is enhanced, while the consequences of the temperature ratio parameter drop the rate of entropy generation in the system.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109916"},"PeriodicalIF":4.9,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of fan speed, sample orientation, and tray structure on heat transfer and food freezing time in batch air blast freezer

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences

Pub Date : 2025-04-04 DOI: 10.1016/j.ijthermalsci.2025.109915

Zheng Xu , Mark Anthony Redo , Yvan Llave , Yasushi Koga , Manabu Watanabe

The batch air blast freezer is commonly used in the food industry, but nonuniform airflow distribution has been an on-going challenge. In this study, experiments and numerical simulations were performed to investigate the effects of varying the fan speed, sample orientation, and tray structure on flow dynamics, local heat transfer coefficient, and transient temperature of loaded samples. Ice crystallization and freezing times of individual samples were predicted, and strong and weak convection locations were identified. Increasing the fan speed from 560 rpm to 840 rpm resulted in a 34%–39% increase in the average surface heat transfer coefficient of the samples in weak convection locations, leading to a reduction in ice crystallization and total freezing times by 20%–29%. The change in sample orientation exhibited a slight difference in freezing time, but the transition from trays to wire shelves demonstrated a substantial enhancement in convective heat transfer by 19%–22%, reducing the total freezing time by 10%–13%.

{"title":"Effect of fan speed, sample orientation, and tray structure on heat transfer and food freezing time in batch air blast freezer","authors":"Zheng Xu , Mark Anthony Redo , Yvan Llave , Yasushi Koga , Manabu Watanabe","doi":"10.1016/j.ijthermalsci.2025.109915","DOIUrl":"10.1016/j.ijthermalsci.2025.109915","url":null,"abstract":"<div><div>The batch air blast freezer is commonly used in the food industry, but nonuniform airflow distribution has been an on-going challenge. In this study, experiments and numerical simulations were performed to investigate the effects of varying the fan speed, sample orientation, and tray structure on flow dynamics, local heat transfer coefficient, and transient temperature of loaded samples. Ice crystallization and freezing times of individual samples were predicted, and strong and weak convection locations were identified. Increasing the fan speed from 560 rpm to 840 rpm resulted in a 34%–39% increase in the average surface heat transfer coefficient of the samples in weak convection locations, leading to a reduction in ice crystallization and total freezing times by 20%–29%. The change in sample orientation exhibited a slight difference in freezing time, but the transition from trays to wire shelves demonstrated a substantial enhancement in convective heat transfer by 19%–22%, reducing the total freezing time by 10%–13%.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109915"},"PeriodicalIF":4.9,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Transition and heat transfer in a water filled cubic cavity with convectively heated sidewalls

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences

Pub Date : 2025-04-03 DOI: 10.1016/j.ijthermalsci.2025.109913

Md Harun Rashid , Feng Xu

Transition and heat transfer in a water filled cubic cavity with convectively heated sidewalls are investigated using three dimensional numerical simulations due to the practical significance in environment and industry. The numerical study is performed for a range of Rayleigh number (Ra) from 10⁰ to 5 × 10⁸ for which the working fluid is water (Pr = 7.74). Such a range of Rayleigh numbers shows a complex transition route to chaos of natural convection involving successive bifurcations. The first pitchfork bifurcation occurs under steady convection regime between Ra = 3.3 × 10⁴ and Ra = 3.4 × 10⁴ based on the topologic invariant relation. Further, more pitchfork bifurcations happen as Ra is increased. Additionally, a Hopf bifurcation occurs between Ra = 2.6 × 10⁹ and Ra = 2.7 × 10⁹ at which natural convection becomes periodic. Further bifurcations may also occur between Ra = 3.2 × 10⁹ and Ra = 3.3 × 10⁹ from periodic to period doubling state and between Ra = 3.3 × 10⁹ and Ra = 3.4 × 10⁹ from period doubling to quasi-periodic state. For a large Rayleigh number of Ra≥3.9 × 10⁹, natural convection becomes chaotic. To characterize the transition to chaos, topologic invariant relation, spectrum, attractor, maximum Lyapunov exponent, and fractal dimension are adopted. In addition, heat transfer is analyzed and scaled under different regimes.

{"title":"Transition and heat transfer in a water filled cubic cavity with convectively heated sidewalls","authors":"Md Harun Rashid , Feng Xu","doi":"10.1016/j.ijthermalsci.2025.109913","DOIUrl":"10.1016/j.ijthermalsci.2025.109913","url":null,"abstract":"<div><div>Transition and heat transfer in a water filled cubic cavity with convectively heated sidewalls are investigated using three dimensional numerical simulations due to the practical significance in environment and industry. The numerical study is performed for a range of Rayleigh number (<em>Ra</em>) from 10<sup>0</sup> to 5 × 10<sup>8</sup> for which the working fluid is water (Pr = 7.74). Such a range of Rayleigh numbers shows a complex transition route to chaos of natural convection involving successive bifurcations. The first pitchfork bifurcation occurs under steady convection regime between <em>Ra</em> = 3.3 × 10<sup>4</sup> and <em>Ra</em> = 3.4 × 10<sup>4</sup> based on the topologic invariant relation. Further, more pitchfork bifurcations happen as <em>Ra</em> is increased. Additionally, a Hopf bifurcation occurs between <em>Ra</em> = 2.6 × 10<sup>9</sup> and <em>Ra</em> = 2.7 × 10<sup>9</sup> at which natural convection becomes periodic. Further bifurcations may also occur between <em>Ra</em> = 3.2 × 10<sup>9</sup> and <em>Ra</em> = 3.3 × 10<sup>9</sup> from periodic to period doubling state and between <em>Ra</em> = 3.3 × 10<sup>9</sup> and <em>Ra</em> = 3.4 × 10<sup>9</sup> from period doubling to quasi-periodic state. For a large Rayleigh number of <em>Ra</em>≥3.9 × 10<sup>9</sup>, natural convection becomes chaotic. To characterize the transition to chaos, topologic invariant relation, spectrum, attractor, maximum Lyapunov exponent, and fractal dimension are adopted. In addition, heat transfer is analyzed and scaled under different regimes.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"214 ","pages":"Article 109913"},"PeriodicalIF":4.9,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0