Pub Date : 2026-01-09DOI: 10.1016/j.csite.2026.107679
Anil Kumar , Mohd Aamir Mumtaz
<div><div>This work examines the thermal as well as hydraulic performance (THP) of a flat plate solar air collector (FPSAC), including integrated combined nozzle jets and spherical turbulence promoters, employing computational fluid dynamics (CFD) simulations based on the RNG <span><math><mrow><mi>k</mi><mo>−</mo><mi>ε</mi></mrow></math></span> turbulence model. The CFD data for the smooth surface duct was validated against existing experimental data and established correlations for smooth surface flat plate collectors, with deviations in Nusselt number and friction factor remaining within acceptable limits, thereby affirming the model reliability. The present study maintained a constant value of sphere-to-hydraulic diameter ratio (<span><math><mrow><msub><mi>D</mi><mrow><mi>S</mi><mi>H</mi></mrow></msub></mrow></math></span>/ <span><math><mrow><msub><mi>D</mi><mi>H</mi></msub></mrow></math></span> = 0.108), while systematically varying the spanwise pitch ratio (<span><math><mrow><msub><mi>P</mi><mrow><mi>S</mi><mi>P</mi><mi>A</mi><mi>N</mi></mrow></msub><mo>/</mo><msub><mi>D</mi><mi>H</mi></msub></mrow></math></span> = 0.70–1.25), streamwise pitch ratio (<span><math><mrow><msub><mi>P</mi><mrow><mi>S</mi><mi>T</mi><mi>R</mi><mi>E</mi><mi>A</mi><mi>M</mi></mrow></msub><mo>/</mo><msub><mi>D</mi><mi>H</mi></msub></mrow></math></span> = 0.53–0.74), and nozzle diameter ratio (<span><math><mrow><msub><mi>D</mi><mrow><mi>O</mi><mi>N</mi></mrow></msub></mrow></math></span>/ <span><math><mrow><msub><mi>D</mi><mrow><mi>I</mi><mi>N</mi></mrow></msub></mrow></math></span> = 0.38–0.60) over a different Reynolds number <span><math><mrow><mo>(</mo><mrow><mi>R</mi><mi>e</mi></mrow><mo>)</mo></mrow></math></span> range of 5500–15,500. Geometric configurations such nozzle jet design, spherical promoters arrangement, flow conditions, and fluid characteristics must be studied to enhance FPSAC system performance. Both <span><math><mrow><msub><mrow><mi>N</mi><mi>u</mi></mrow><mrow><mi>N</mi><mi>S</mi></mrow></msub><mo>/</mo><msub><mrow><mi>N</mi><mi>u</mi></mrow><mrow><mi>S</mi><mi>S</mi></mrow></msub></mrow></math></span> and THP rise with <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span>, indicating a considerable influence on turbulence promoter geometry. The best performance was achieved at <span><math><mrow><msub><mi>P</mi><mrow><mi>S</mi><mi>P</mi><mi>A</mi><mi>N</mi></mrow></msub><mo>/</mo><msub><mi>D</mi><mi>H</mi></msub><mo>=</mo><mn>1.04</mn></mrow></math></span>, <span><math><mrow><msub><mi>P</mi><mrow><mi>S</mi><mi>T</mi><mi>R</mi><mi>E</mi><mi>A</mi><mi>M</mi></mrow></msub><mo>/</mo><msub><mi>D</mi><mi>H</mi></msub><mo>=</mo><mn>0.60</mn></mrow></math></span>, and <span><math><mrow><msub><mi>D</mi><mrow><mi>O</mi><mi>N</mi></mrow></msub><mo>/</mo><msub><mi>D</mi><mrow><mi>I</mi><mi>N</mi></mrow></msub><mo>=</mo><mn>0.45</mn></mrow></math></span>. These findings show that geometric optimization is crucial to efficiency in turbulence flow.</div></
{"title":"Computational study of combined nozzle jet and spherical promoters for enhanced heat transfer in flat plate solar air collector","authors":"Anil Kumar , Mohd Aamir Mumtaz","doi":"10.1016/j.csite.2026.107679","DOIUrl":"10.1016/j.csite.2026.107679","url":null,"abstract":"<div><div>This work examines the thermal as well as hydraulic performance (THP) of a flat plate solar air collector (FPSAC), including integrated combined nozzle jets and spherical turbulence promoters, employing computational fluid dynamics (CFD) simulations based on the RNG <span><math><mrow><mi>k</mi><mo>−</mo><mi>ε</mi></mrow></math></span> turbulence model. The CFD data for the smooth surface duct was validated against existing experimental data and established correlations for smooth surface flat plate collectors, with deviations in Nusselt number and friction factor remaining within acceptable limits, thereby affirming the model reliability. The present study maintained a constant value of sphere-to-hydraulic diameter ratio (<span><math><mrow><msub><mi>D</mi><mrow><mi>S</mi><mi>H</mi></mrow></msub></mrow></math></span>/ <span><math><mrow><msub><mi>D</mi><mi>H</mi></msub></mrow></math></span> = 0.108), while systematically varying the spanwise pitch ratio (<span><math><mrow><msub><mi>P</mi><mrow><mi>S</mi><mi>P</mi><mi>A</mi><mi>N</mi></mrow></msub><mo>/</mo><msub><mi>D</mi><mi>H</mi></msub></mrow></math></span> = 0.70–1.25), streamwise pitch ratio (<span><math><mrow><msub><mi>P</mi><mrow><mi>S</mi><mi>T</mi><mi>R</mi><mi>E</mi><mi>A</mi><mi>M</mi></mrow></msub><mo>/</mo><msub><mi>D</mi><mi>H</mi></msub></mrow></math></span> = 0.53–0.74), and nozzle diameter ratio (<span><math><mrow><msub><mi>D</mi><mrow><mi>O</mi><mi>N</mi></mrow></msub></mrow></math></span>/ <span><math><mrow><msub><mi>D</mi><mrow><mi>I</mi><mi>N</mi></mrow></msub></mrow></math></span> = 0.38–0.60) over a different Reynolds number <span><math><mrow><mo>(</mo><mrow><mi>R</mi><mi>e</mi></mrow><mo>)</mo></mrow></math></span> range of 5500–15,500. Geometric configurations such nozzle jet design, spherical promoters arrangement, flow conditions, and fluid characteristics must be studied to enhance FPSAC system performance. Both <span><math><mrow><msub><mrow><mi>N</mi><mi>u</mi></mrow><mrow><mi>N</mi><mi>S</mi></mrow></msub><mo>/</mo><msub><mrow><mi>N</mi><mi>u</mi></mrow><mrow><mi>S</mi><mi>S</mi></mrow></msub></mrow></math></span> and THP rise with <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span>, indicating a considerable influence on turbulence promoter geometry. The best performance was achieved at <span><math><mrow><msub><mi>P</mi><mrow><mi>S</mi><mi>P</mi><mi>A</mi><mi>N</mi></mrow></msub><mo>/</mo><msub><mi>D</mi><mi>H</mi></msub><mo>=</mo><mn>1.04</mn></mrow></math></span>, <span><math><mrow><msub><mi>P</mi><mrow><mi>S</mi><mi>T</mi><mi>R</mi><mi>E</mi><mi>A</mi><mi>M</mi></mrow></msub><mo>/</mo><msub><mi>D</mi><mi>H</mi></msub><mo>=</mo><mn>0.60</mn></mrow></math></span>, and <span><math><mrow><msub><mi>D</mi><mrow><mi>O</mi><mi>N</mi></mrow></msub><mo>/</mo><msub><mi>D</mi><mrow><mi>I</mi><mi>N</mi></mrow></msub><mo>=</mo><mn>0.45</mn></mrow></math></span>. These findings show that geometric optimization is crucial to efficiency in turbulence flow.</div></","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"78 ","pages":"Article 107679"},"PeriodicalIF":6.4,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956599","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 : 2026-01-09DOI: 10.1016/j.csite.2026.107648
Fatima Ezzahra Allali, Hicham Fatnassi, Hassan Demrati, Abderrahim Amarraque, Rachid Bouharroud, Fouad Elame, Ahmed Aharoune, Ahmed Wifaya
Greenhouse systems play a critical role in sustaining crop production in arid and semi-arid regions, where open-field agriculture is constrained by harsh climatic conditions and chronic water scarcity. In the southern Mediterranean basin, particularly in Morocco, traditional greenhouses, such as the widely adopted Canarian-type greenhouse, are increasingly challenged by rising temperatures and growing climate variability stressing the need for climate-resilient designs tailored to local conditions.
{"title":"Design and Evaluation of Climate-Adaptive Greenhouses for Semi-Arid regions Using CFD model","authors":"Fatima Ezzahra Allali, Hicham Fatnassi, Hassan Demrati, Abderrahim Amarraque, Rachid Bouharroud, Fouad Elame, Ahmed Aharoune, Ahmed Wifaya","doi":"10.1016/j.csite.2026.107648","DOIUrl":"https://doi.org/10.1016/j.csite.2026.107648","url":null,"abstract":"Greenhouse systems play a critical role in sustaining crop production in arid and semi-arid regions, where open-field agriculture is constrained by harsh climatic conditions and chronic water scarcity. In the southern Mediterranean basin, particularly in Morocco, traditional greenhouses, such as the widely adopted Canarian-type greenhouse, are increasingly challenged by rising temperatures and growing climate variability stressing the need for climate-resilient designs tailored to local conditions.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"4 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956584","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 : 2026-01-09DOI: 10.1016/j.csite.2026.107689
S. Sungworagarn , U. Chuensumran , P. Sathitruangsak , S. Lohmoh , S. Jannil , T. Madhiyanon
Waterless live transport of freshwater prawns (Macrobrachium rosenbergii) offers a promising alternative to traditional water-based shipment, drastically reducing freight costs and physical trauma. However, its commercial adoption has been hindered by the lack of a reliable, scalable method for safe anesthetization without cold shock or mortality. Therefore, this study aims to develop and validate an integrated, engineering-standardized shipment protocol to enable practical, high-survival waterless transport of M. rosenbergii.
We designed a dual-output refrigeration prototype that simultaneously generates chilled (5 °C) and hot (43 °C) water via custom-designed heat exchangers, precisely controlled by a PLC to deliver a consistent chilling rate of 9.87 ± 0.63 °C/h (or lower, if required). This gradually reduced prawn temperature from ambient (25–27.5 °C) to 16.5 ± 0.2 °C over 60–75 min. The system was paired with a five-stage commercial protocol: acclimatization, thermal anesthetization, moisture-preserving live packing, temperature-stable transport (16–18 °C), and revitalization.
Performance was validated through simulated (8–14 h) and real 10-h road transport trials. The approach achieved exceptional survival rates (91.3–98.65 % in simulation; 95.63 % in field trials), demonstrating that accurately controlled thermal anesthetization and an appropriate live transport protocol can safely replace immersion transport. This work presents the first fully engineered, field-validated system for waterless live shipment of M. rosenbergii—scalable, energy-efficient (COP = 3.16), and directly applicable to tropical aquaculture supply chains.
{"title":"Design and field validation of thermal anesthetization system for waterless live transport of giant freshwater prawn (Macrobrachium rosenbergii)","authors":"S. Sungworagarn , U. Chuensumran , P. Sathitruangsak , S. Lohmoh , S. Jannil , T. Madhiyanon","doi":"10.1016/j.csite.2026.107689","DOIUrl":"10.1016/j.csite.2026.107689","url":null,"abstract":"<div><div>Waterless live transport of freshwater prawns (<em>Macrobrachium rosenbergii</em>) offers a promising alternative to traditional water-based shipment, drastically reducing freight costs and physical trauma. However, its commercial adoption has been hindered by the lack of a reliable, scalable method for safe anesthetization without cold shock or mortality. Therefore, this study aims to develop and validate an integrated, engineering-standardized shipment protocol to enable practical, high-survival waterless transport of <em>M. rosenbergii</em>.</div><div>We designed a dual-output refrigeration prototype that simultaneously generates chilled (5 °C) and hot (43 °C) water via custom-designed heat exchangers, precisely controlled by a PLC to deliver a consistent chilling rate of 9.87 ± 0.63 °C/h (or lower, if required). This gradually reduced prawn temperature from ambient (25–27.5 °C) to 16.5 ± 0.2 °C over 60–75 min. The system was paired with a five-stage commercial protocol: acclimatization, thermal anesthetization, moisture-preserving live packing, temperature-stable transport (16–18 °C), and revitalization.</div><div>Performance was validated through simulated (8–14 h) and real 10-h road transport trials. The approach achieved exceptional survival rates (91.3–98.65 % in simulation; 95.63 % in field trials), demonstrating that accurately controlled thermal anesthetization and an appropriate live transport protocol can safely replace immersion transport. This work presents the first fully engineered, field-validated system for waterless live shipment of <em>M. rosenbergii</em>—scalable, energy-efficient (COP = 3.16), and directly applicable to tropical aquaculture supply chains.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"78 ","pages":"Article 107689"},"PeriodicalIF":6.4,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956692","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 : 2026-01-09DOI: 10.1016/j.csite.2026.107687
Ying Sun , Lin Lyu , Miaomiao Wen , Junjie Liang
The development of accurate and reliable combustion kinetic models is imperative to advance the application of diesel/biodiesel blended fuels in marine engines. This study developed a reduced kinetic mechanism comprising six surrogate components (n-hexadecane, 2-methylheptane, methylcyclohexane, n-propyl benzene, methyl decanoate, and methyl-9-decenoate) based on the decoupling method. The mechanism encompasses the critical pathways from the oxidation of the components to the formation of polycyclic aromatic hydrocarbons, consisting of 129 species and 400 reactions. To comprehensively evaluate its performance, rigorous validations of the mechanism were conducted against multi-scale experimental data, spanning the fundamental combustion properties of the surrogate components, the spray combustion characteristics of diesel/biodiesel obtained in a constant volume combustion chamber, and the ignition and heat release processes of the blended fuel in a practical marine engine. The comparisons indicate that the proposed mechanism reproduces well the experimental results across various conditions, confirming the capability of the developed multi-component mechanism to support in-depth analysis and optimization of heat release process for biodiesel/diesel blended fuel in marine engines.
{"title":"A reduced chemical kinetic mechanism for diesel/biodiesel surrogate fuel: Formulation and validation","authors":"Ying Sun , Lin Lyu , Miaomiao Wen , Junjie Liang","doi":"10.1016/j.csite.2026.107687","DOIUrl":"10.1016/j.csite.2026.107687","url":null,"abstract":"<div><div>The development of accurate and reliable combustion kinetic models is imperative to advance the application of diesel/biodiesel blended fuels in marine engines. This study developed a reduced kinetic mechanism comprising six surrogate components (n-hexadecane, 2-methylheptane, methylcyclohexane, n-propyl benzene, methyl decanoate, and methyl-9-decenoate) based on the decoupling method. The mechanism encompasses the critical pathways from the oxidation of the components to the formation of polycyclic aromatic hydrocarbons, consisting of 129 species and 400 reactions. To comprehensively evaluate its performance, rigorous validations of the mechanism were conducted against multi-scale experimental data, spanning the fundamental combustion properties of the surrogate components, the spray combustion characteristics of diesel/biodiesel obtained in a constant volume combustion chamber, and the ignition and heat release processes of the blended fuel in a practical marine engine. The comparisons indicate that the proposed mechanism reproduces well the experimental results across various conditions, confirming the capability of the developed multi-component mechanism to support in-depth analysis and optimization of heat release process for biodiesel/diesel blended fuel in marine engines.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"78 ","pages":"Article 107687"},"PeriodicalIF":6.4,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956578","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}
For traditional energy systems, the setpoint temperature was set following standards and codes. However, for optimizing the systems by control methods, the precondition for this was that the relationships between the setpoint temperature and system indicators were clear. For the newly designed, integrated solar collector and air-source heat pump system with PCM tank, these relationships had not been previously explored. To address this research gap, this study examined effects of different setpoint temperatures on the energy, economic, and environmental performance. The genetic algorithm was applied to conduct the optimization for maximizing comprehensive performance. An open-air swimming pool served as the case study, with a total heating load of 7.44×105 kWh. Each air-source heat pump in the system had a rated heating capacity of 500 kW and weighed approximately 2 tons, based on market data. Results indicated that system coefficient of performance was respectively 3.46 and 7.92 when pool water setpoint temperature during preheating period was 27°C and 31°C, increased by 129.1%. After optimization, system coefficient of performance achieved 8.92, and total melting time of PCM tank was 143.4 hours. This study offered valuable guidance for optimizing setpoint temperatures in integrated solar collector and air-source heat pump system with PCM tank.
{"title":"Optimal control of an integrated solar collector and air-source heat pump system with PCM tank","authors":"Yantong Li, Zixi Mo, Junhan Liang, Weihao Chen, Sikai Zou, Zebo Wu, Changhong Wang, Tingting Wu, Huibin Yin, Gechuanqi Pan","doi":"10.1016/j.csite.2026.107680","DOIUrl":"https://doi.org/10.1016/j.csite.2026.107680","url":null,"abstract":"For traditional energy systems, the setpoint temperature was set following standards and codes. However, for optimizing the systems by control methods, the precondition for this was that the relationships between the setpoint temperature and system indicators were clear. For the newly designed, integrated solar collector and air-source heat pump system with PCM tank, these relationships had not been previously explored. To address this research gap, this study examined effects of different setpoint temperatures on the energy, economic, and environmental performance. The genetic algorithm was applied to conduct the optimization for maximizing comprehensive performance. An open-air swimming pool served as the case study, with a total heating load of 7.44×10<ce:sup loc=\"post\">5</ce:sup> kWh. Each air-source heat pump in the system had a rated heating capacity of 500 kW and weighed approximately 2 tons, based on market data. Results indicated that system coefficient of performance was respectively 3.46 and 7.92 when pool water setpoint temperature during preheating period was 27°C and 31°C, increased by 129.1%. After optimization, system coefficient of performance achieved 8.92, and total melting time of PCM tank was 143.4 hours. This study offered valuable guidance for optimizing setpoint temperatures in integrated solar collector and air-source heat pump system with PCM tank.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"38 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956582","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}
Passive cold start remains a major challenge to Proton Exchange Membrane Fuel Cells (PEMFCs), with thermal imbalance during warm-up being a key challenge. Uneven temperatures can cause startup failure and long-term degradation. This study experimentally evaluates a new passive heating strategy using alternating coolant flow to improve thermal management. Experiments are conducted using a 3-cell thermal-emulation stack (100 cm2 per cell, ≈230 W thermal power), designed to replicate the edge and central-cell thermal behavior of real PEMFC stacks at −10 °C. The proposed method relies on alternating-flow operation, in which the coolant periodically reverses direction inside the cooling channels, enhancing heat retention and redistribution. This configuration is systematically compared with conventional no-flow (no coolant circulation) and unidirectional-flow (constant flow direction) using key thermal metrics, including temperature rise, vertical and horizontal uniformity, and forced-convection losses. Results show that the no-flow configuration enables rapid heating but induces significant inter-cell temperature differences, resulting in poor horizontal uniformity. Unidirectional configuration provides better horizontal uniformity but limits heating capability and leads to vertical temperature stratification at the cell level due to convective heat removal. The proposed alternating-flow strategy outperforms both reference cases, achieving a 32.3 °C temperature rise in 85 s, reducing vertical gradients by 90 %, and decreasing inter-cell temperature dispersion by more than 57 %. Under these conditions, the active surface exceeds 0 °C, enabling safe cold start. An adaptive strategy is proposed, dynamically switching flow modes based on internal thermal monitoring. This scalable approach offers a promising passive solution for cold-start management in PEMFCs.
{"title":"Experimental investigation of passive alternating flow heating strategies for PEMFC cold start","authors":"El Ahmadi Mortada , Bégot Sylvie , Harel Fabien , Layes Guillaume , Lepiller Valérie","doi":"10.1016/j.csite.2026.107693","DOIUrl":"10.1016/j.csite.2026.107693","url":null,"abstract":"<div><div>Passive cold start remains a major challenge to Proton Exchange Membrane Fuel Cells (PEMFCs), with thermal imbalance during warm-up being a key challenge. Uneven temperatures can cause startup failure and long-term degradation. This study experimentally evaluates a new passive heating strategy using alternating coolant flow to improve thermal management. Experiments are conducted using a 3-cell thermal-emulation stack (100 cm<sup>2</sup> per cell, ≈230 W thermal power), designed to replicate the edge and central-cell thermal behavior of real PEMFC stacks at −10 °C. The proposed method relies on alternating-flow operation, in which the coolant periodically reverses direction inside the cooling channels, enhancing heat retention and redistribution. This configuration is systematically compared with conventional no-flow (no coolant circulation) and unidirectional-flow (constant flow direction) using key thermal metrics, including temperature rise, vertical and horizontal uniformity, and forced-convection losses. Results show that the no-flow configuration enables rapid heating but induces significant inter-cell temperature differences, resulting in poor horizontal uniformity. Unidirectional configuration provides better horizontal uniformity but limits heating capability and leads to vertical temperature stratification at the cell level due to convective heat removal. The proposed alternating-flow strategy outperforms both reference cases, achieving a 32.3 °C temperature rise in 85 s, reducing vertical gradients by 90 %, and decreasing inter-cell temperature dispersion by more than 57 %. Under these conditions, the active surface exceeds 0 °C, enabling safe cold start. An adaptive strategy is proposed, dynamically switching flow modes based on internal thermal monitoring. This scalable approach offers a promising passive solution for cold-start management in PEMFCs.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"78 ","pages":"Article 107693"},"PeriodicalIF":6.4,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956691","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 : 2026-01-09DOI: 10.1016/j.csite.2026.107696
Xin Li , Qiang Li , Jin Zhang , Junli Sun , Yantong Liu , Jinmei Li
Gas eruption induced by thermal runaway (TR) of lithium-ion batteries (LIBs) is one of the critical issues restricting their safe application. Accurate measurement of eruption dynamic parameters is crucial for risk assessment and safety design. To investigate the State of Charge (SOC)-dependent venting behavior during TR, this study employed a three-axis force sensor to directly capture the recoil force () and mass loss () based on the principle of momentum conservation, deriving the mass flow rate () and venting velocity (), which effectively overcomes the technical bottleneck of traditional methods. The results reveal a distinct two-stage characteristic of TR: In the safety valve opening stage, the peak recoil force is 0.16–0.29 N, independent of SOC; In the TR stage, dynamic parameters are SOC-dependent, with mild mass loss of 5.01–5.77 g under low SOC (≤75 %). At 100 % SOC, the maximum venting velocity reaches 497.6 ± 38.46 m s−1, with total mass loss of 26.38 ± 1.02 g and TR duration of 1017 ± 167 ms, exhibiting intense energy release. This study uncovers the SOC-dependent differences between the two TR stages, providing key parameters for battery safety design.
{"title":"SOC-dependent venting behavior of thermal runaway in 18,650 LiFePO4 batteries","authors":"Xin Li , Qiang Li , Jin Zhang , Junli Sun , Yantong Liu , Jinmei Li","doi":"10.1016/j.csite.2026.107696","DOIUrl":"10.1016/j.csite.2026.107696","url":null,"abstract":"<div><div>Gas eruption induced by thermal runaway (TR) of lithium-ion batteries (LIBs) is one of the critical issues restricting their safe application. Accurate measurement of eruption dynamic parameters is crucial for risk assessment and safety design. To investigate the State of Charge (SOC)-dependent venting behavior during TR, this study employed a three-axis force sensor to directly capture the recoil force (<span><math><mrow><msub><mi>F</mi><mi>r</mi></msub></mrow></math></span>) and mass loss (<span><math><mrow><msub><mo>Δ</mo><mi>m</mi></msub></mrow></math></span>) based on the principle of momentum conservation, deriving the mass flow rate (<span><math><mrow><mover><mi>m</mi><mo>˙</mo></mover></mrow></math></span>) and venting velocity (<span><math><mrow><msub><mi>v</mi><mi>g</mi></msub></mrow></math></span>), which effectively overcomes the technical bottleneck of traditional methods. The results reveal a distinct two-stage characteristic of TR: In the safety valve opening stage, the peak recoil force is 0.16–0.29 N, independent of SOC; In the TR stage, dynamic parameters are SOC-dependent, with mild mass loss of 5.01–5.77 g under low SOC (≤75 %). At 100 % SOC, the maximum venting velocity reaches 497.6 ± 38.46 m s<sup>−1</sup>, with total mass loss of 26.38 ± 1.02 g and TR duration of 1017 ± 167 ms, exhibiting intense energy release. This study uncovers the SOC-dependent differences between the two TR stages, providing key parameters for battery safety design.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"78 ","pages":"Article 107696"},"PeriodicalIF":6.4,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956583","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 : 2026-01-09DOI: 10.1016/j.csite.2026.107691
Huiting Bian , Jianing Liu , Yang Wang , Yida Kuang , Yiping Zeng , Chi-Min Shu , Huiling Jiang , Yanli Zhao
Investigation of biomass pyrolysis is of particular interest for the production and use of biofuels, composite and building materials with broad applications. Cucumber vine, an agricultural waste from cucumber harvesting, holds potential as biopolymer fiber for composites. Understanding its pyrolysis behavior is key to elucidate thermal stability and complex pyrolysis process. This study aims to explore pyrolysis characteristics for primordial and chemically treated cucumber vine by experiment and the combined kinetic analysis. A synergistic treatment of 5 % sodium hydroxide, 20 % acetic acid +5 % sodium hypochlorite and 5 % silane coupling agent was applied, and its impact was evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Based on inert thermogravimetric analysis, kinetic triplets were determined using both model-free and model-fitting approaches, and thereby the optimal reaction mechanisms were reconstructed by considering kinetic compensation effect. Results indicated that chemical treatment effectively isolated cellulose from raw samples with reduction of amorphous components, like hemicellulose, and slight promotion of crystallinity by FTIR and XRD analysis. Thermogravimetric analysis found the lessened water absorption with a narrower region and the more distinct characteristics of three reaction stages for treated samples. The initial pyrolysis temperature and average activation energy increased from 216.93 to 233.80 °C and from 88.54 to 103.16 kJ/mol, respectively. Fn reaction model best described the pyrolysis of both raw and treated samples with further refinement via Sestak-Berggren model. Thermodynamic analysis confirmed an increase of 15.73 kJ/mol in average enthalpy, supporting the reaction's non-spontaneous and endothermic nature.
{"title":"Thermal degradation behavior and kinetic analysis of chemically modified cucumber vine biomass for sustainable thermal applications","authors":"Huiting Bian , Jianing Liu , Yang Wang , Yida Kuang , Yiping Zeng , Chi-Min Shu , Huiling Jiang , Yanli Zhao","doi":"10.1016/j.csite.2026.107691","DOIUrl":"10.1016/j.csite.2026.107691","url":null,"abstract":"<div><div>Investigation of biomass pyrolysis is of particular interest for the production and use of biofuels, composite and building materials with broad applications. Cucumber vine, an agricultural waste from cucumber harvesting, holds potential as biopolymer fiber for composites. Understanding its pyrolysis behavior is key to elucidate thermal stability and complex pyrolysis process. This study aims to explore pyrolysis characteristics for primordial and chemically treated cucumber vine by experiment and the combined kinetic analysis. A synergistic treatment of 5 % sodium hydroxide, 20 % acetic acid +5 % sodium hypochlorite and 5 % silane coupling agent was applied, and its impact was evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Based on inert thermogravimetric analysis, kinetic triplets were determined using both model-free and model-fitting approaches, and thereby the optimal reaction mechanisms were reconstructed by considering kinetic compensation effect. Results indicated that chemical treatment effectively isolated cellulose from raw samples with reduction of amorphous components, like hemicellulose, and slight promotion of crystallinity by FTIR and XRD analysis. Thermogravimetric analysis found the lessened water absorption with a narrower region and the more distinct characteristics of three reaction stages for treated samples. The initial pyrolysis temperature and average activation energy increased from 216.93 to 233.80 °C and from 88.54 to 103.16 kJ/mol, respectively. <em>F</em><sub>n</sub> reaction model best described the pyrolysis of both raw and treated samples with further refinement via Sestak-Berggren model. Thermodynamic analysis confirmed an increase of 15.73 kJ/mol in average enthalpy, supporting the reaction's non-spontaneous and endothermic nature.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"78 ","pages":"Article 107691"},"PeriodicalIF":6.4,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956585","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 : 2026-01-08DOI: 10.1016/j.csite.2026.107674
Jianan Gao, Shugang Li, Fengliang Wu, Li Ma
The issue of heat hazard caused by high-temperature surrounding rock in deep mines is becoming increasingly prominent, while the potential for geothermal energy exploitation form surrounding rock is considerable. Therefore, the synergetic technology of mine geothermal mining and heat hazard prevention has garnered significant attention. Previous studies have primarily focused on the coupled effects of open-loop systems and formation cooling, with limited exploration of the mechanisms underlying the cooling effects of geothermal extraction from closed-loop systems on roadway airflow. This research utilizes COMSOL software to establish a coupled heat transfer and seepage model for the synergistic implementation of heat extraction and cooling through buried tubes within the surrounding rock. The heat transfer behavior of surrounding rock, the cooling effect on airflow, and the geothermal extraction performance during long-term heat transfer processes are studied. The results indicate that when groundwater seeps horizontally and perpendicularly to the axial direction of the roadway, and a single buried tube is located in the upstream seepage zone of the roadway, the cold domain range on the downstream side of the fluid cooling influence zone in the buried tube is significantly expanded, which is more likely to overlap with the cold domain range on the upstream side of the airflow cooling influence zone in the roadway and form a cold accumulation, resulting in the best cooling effect of the airflow. As the distance between the buried tube and roadway increases, the cooling effect of the airflow decreases, and the fluid temperature at the outlet of the buried tube and thermal power increase, but the improvement in both becomes negligible once the distance reaches a certain value. Lowering the fluid temperature at the inlet of the buried tube has a significant effect on improving the cooling effect of the airflow and thermal power, but it can cause a decrease in the fluid temperature at the outlet of the buried tube. Reducing the fluid mass flow rate of the buried tube can significantly increase the fluid temperature at the outlet of the buried tube, while increasing the fluid mass flow rate of the buried tube can enhance the cooling effect of the airflow and thermal power, but the impact on both is no longer significant after the fluid mass flow rate of the buried tube increases to a certain value.
{"title":"Numerical simulation of synergistic geothermal energy extraction and roadway airflow cooling through buried tubes in the surrounding rock in deep high-temperature mines","authors":"Jianan Gao, Shugang Li, Fengliang Wu, Li Ma","doi":"10.1016/j.csite.2026.107674","DOIUrl":"10.1016/j.csite.2026.107674","url":null,"abstract":"<div><div>The issue of heat hazard caused by high-temperature surrounding rock in deep mines is becoming increasingly prominent, while the potential for geothermal energy exploitation form surrounding rock is considerable. Therefore, the synergetic technology of mine geothermal mining and heat hazard prevention has garnered significant attention. Previous studies have primarily focused on the coupled effects of open-loop systems and formation cooling, with limited exploration of the mechanisms underlying the cooling effects of geothermal extraction from closed-loop systems on roadway airflow. This research utilizes COMSOL software to establish a coupled heat transfer and seepage model for the synergistic implementation of heat extraction and cooling through buried tubes within the surrounding rock. The heat transfer behavior of surrounding rock, the cooling effect on airflow, and the geothermal extraction performance during long-term heat transfer processes are studied. The results indicate that when groundwater seeps horizontally and perpendicularly to the axial direction of the roadway, and a single buried tube is located in the upstream seepage zone of the roadway, the cold domain range on the downstream side of the fluid cooling influence zone in the buried tube is significantly expanded, which is more likely to overlap with the cold domain range on the upstream side of the airflow cooling influence zone in the roadway and form a cold accumulation, resulting in the best cooling effect of the airflow. As the distance between the buried tube and roadway increases, the cooling effect of the airflow decreases, and the fluid temperature at the outlet of the buried tube and thermal power increase, but the improvement in both becomes negligible once the distance reaches a certain value. Lowering the fluid temperature at the inlet of the buried tube has a significant effect on improving the cooling effect of the airflow and thermal power, but it can cause a decrease in the fluid temperature at the outlet of the buried tube. Reducing the fluid mass flow rate of the buried tube can significantly increase the fluid temperature at the outlet of the buried tube, while increasing the fluid mass flow rate of the buried tube can enhance the cooling effect of the airflow and thermal power, but the impact on both is no longer significant after the fluid mass flow rate of the buried tube increases to a certain value.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"78 ","pages":"Article 107674"},"PeriodicalIF":6.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956597","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 : 2026-01-08DOI: 10.1016/j.csite.2025.107599
Li Ma , Xin Wang , Hui Wang , Fang Lou , Xixi Liu , Gaoming Wei , Ruizhi Guo
Fly ash grouting is an effective technical to prevent the coal spontaneous combustion. However, fly ash slurry has its problems such as being prone to sedimentation and not easy to solidify, which has a negative impact on the prevention and control of coal spontaneous combustion. To enhance fly ash colloid's efficacy in preventing coal spontaneous combustion, an XG/HPMC fly ash colloid incorporating polymer xanthan gum (XG) and hydroxypropyl methylcellulose (HPMC) is developed. The ratio of the XG/HPMC fly ash colloid is optimized by integrating single -factor experiments and response surface analysis. The microstructure and rheological behavior of the XG/HPMC fly ash colloid are characterized, and its anti - spontaneous combustion properties are compared and analyzed. The results reveal that the gelling properties of XG/HPMC fly ash colloid are better during the colloid concentration is 0.78 %, the colloid mass ratio is 65:35, and the water-cement ratio is 10.38:1, respectively. Microscopic tests indicate that the functional groups of XG and HPMC have been successfully graft-polymerized onto the surface of the fly ash colloid. XG/HPMC fly ash colloid belongs to yield pseudoplastic fluid. It exhibits shear - thinning behavior, allowing it to flow easily and cover the coal surface, thereby effectively preventing oxygen from contacting coal. Moreover, the inhibition rate of XG/HPMC fly ash colloid on is 77.47 % higher than of raw coal in 100 °C. XG/HPMC fly ash colloid treated coal maximum weight loss rate is reduced by 4.41 % that compared with the raw coal. Furthermore, the XG/HPMC fly ash colloid lowers the content of oxygen-containing functional groups in coal and prevents chain reactions, thus curbing coal spontaneous combustion. The results provide support for achieving efficient fire prevention performance of fly ash colloid.
{"title":"Response surface optimizing XG/HPMC fly ash colloid to inhabit coal spontaneous combustion: An experimental study","authors":"Li Ma , Xin Wang , Hui Wang , Fang Lou , Xixi Liu , Gaoming Wei , Ruizhi Guo","doi":"10.1016/j.csite.2025.107599","DOIUrl":"10.1016/j.csite.2025.107599","url":null,"abstract":"<div><div>Fly ash grouting is an effective technical to prevent the coal spontaneous combustion. However, fly ash slurry has its problems such as being prone to sedimentation and not easy to solidify, which has a negative impact on the prevention and control of coal spontaneous combustion. To enhance fly ash colloid's efficacy in preventing coal spontaneous combustion, an XG/HPMC fly ash colloid incorporating polymer xanthan gum (XG) and hydroxypropyl methylcellulose (HPMC) is developed. The ratio of the XG/HPMC fly ash colloid is optimized by integrating single -factor experiments and response surface analysis. The microstructure and rheological behavior of the XG/HPMC fly ash colloid are characterized, and its anti - spontaneous combustion properties are compared and analyzed. The results reveal that the gelling properties of XG/HPMC fly ash colloid are better during the colloid concentration is 0.78 %, the colloid mass ratio is 65:35, and the water-cement ratio is 10.38:1, respectively. Microscopic tests indicate that the functional groups of XG and HPMC have been successfully graft-polymerized onto the surface of the fly ash colloid. XG/HPMC fly ash colloid belongs to yield pseudoplastic fluid. It exhibits shear - thinning behavior, allowing it to flow easily and cover the coal surface, thereby effectively preventing oxygen from contacting coal. Moreover, the inhibition rate of XG/HPMC fly ash colloid on is 77.47 % higher than of raw coal in 100 °C. XG/HPMC fly ash colloid treated coal maximum weight loss rate is reduced by 4.41 % that compared with the raw coal. Furthermore, the XG/HPMC fly ash colloid lowers the content of oxygen-containing functional groups in coal and prevents chain reactions, thus curbing coal spontaneous combustion. The results provide support for achieving efficient fire prevention performance of fly ash colloid.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"78 ","pages":"Article 107599"},"PeriodicalIF":6.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923191","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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