Pub Date : 2026-04-01Epub Date: 2026-03-04DOI: 10.1016/j.csite.2026.107876
Christian Boßer , David Sedarsky
Challenging heat rejection caused by small temperature differences between ambient air and low-temperature proton exchange membrane fuel cells (PEMFC) lead to significantly increased radiator dimension and fan power requirements, increasing the need for alternative cooling solutions. To overcome these limitations, the high latent heat of water that is produced in the hydrogen PEMFC can be utilized to enhance the overall system heat rejection.
A novel bubble column evaporator concept for fuel cell (FC) thermal management has been developed. High heat and mass transfer rates make bubble columns a promising alternative to evaporate the product water. It consists of a semi-closed loop in which heat is transferred from the FC coolant to a secondary water circuit that is evaporatively cooled by injecting the FC exhaust air into a bubble column. This solution utilizes only air and water for cooling, provides additional heat storage, improves with increasing altitude and does not increase the vehicle's drag.
We present the novel counterflow bubble column evaporator concept together with proof-of-concept measurements to demonstrate its viability by validating theoretically predicted heat rejection rates. Higher superficial gas velocities than previously reported have been investigated to reduce system size, reaching up to 1.22 m/s. Based on the presented measurements and a verified heavy-duty PEMFC truck model, this approach could complement the conventional truck cooling system with 153 kW additional heat rejection for 23 min with 50 kg of water storage. At 20 °C, this corresponds to an increase of over 40% compared to the conventional cooling system alone.
{"title":"Experimental proof-of-concept of bubble column evaporative cooling for PEMFC heavy-duty vehicle thermal management","authors":"Christian Boßer , David Sedarsky","doi":"10.1016/j.csite.2026.107876","DOIUrl":"10.1016/j.csite.2026.107876","url":null,"abstract":"<div><div>Challenging heat rejection caused by small temperature differences between ambient air and low-temperature proton exchange membrane fuel cells (PEMFC) lead to significantly increased radiator dimension and fan power requirements, increasing the need for alternative cooling solutions. To overcome these limitations, the high latent heat of water that is produced in the hydrogen PEMFC can be utilized to enhance the overall system heat rejection.</div><div>A novel bubble column evaporator concept for fuel cell (FC) thermal management has been developed. High heat and mass transfer rates make bubble columns a promising alternative to evaporate the product water. It consists of a semi-closed loop in which heat is transferred from the FC coolant to a secondary water circuit that is evaporatively cooled by injecting the FC exhaust air into a bubble column. This solution utilizes only air and water for cooling, provides additional heat storage, improves with increasing altitude and does not increase the vehicle's drag.</div><div>We present the novel counterflow bubble column evaporator concept together with proof-of-concept measurements to demonstrate its viability by validating theoretically predicted heat rejection rates. Higher superficial gas velocities than previously reported have been investigated to reduce system size, reaching up to 1.22 m/s. Based on the presented measurements and a verified heavy-duty PEMFC truck model, this approach could complement the conventional truck cooling system with 153 kW additional heat rejection for 23 min with 50 kg of water storage. At 20 °C, this corresponds to an increase of over 40% compared to the conventional cooling system alone.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107876"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147360580","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 : 2026-04-01Epub Date: 2026-03-07DOI: 10.1016/j.csite.2026.107915
Ramakrishnan Sambasivam, Annamalai Kandasamy
Global energy crisis and environmental issues also have encouraged the quest for renewable and sustainable solutions to the traditional fossil fuels. Alternative biofuels based on water plants offer great potential as they are fast growing, do not compete with food crops and produce high biomass. In the present work, an aquatic weed Hydrilla verticillata was examined as a likely feedstock for biodiesel production. Solvent extracted oil by using n-hexane solvent helps in increasing the yield efficiency and fuel quality from Hydrilla plant feedstocks. The thus obtained oil was mixed with diesel in different ratios and experiments were carried out in a compression ignition engine. Prior to the use of this process analysis work done on zirconia material coated (0.5 mm) that is piston for checking the heat transfer of the piston from top to down with help of ANSYS software and also compared without coated engine. Further to enhance combustion and robustness across the blend range, A zirconia-based thermal barrier coated material was applied to the piston crown to increase in-cylinder heat and pressure to retention and minimize heat losses to the bottom of the piston. The zirconia coating promoted the higher Hydrilla–diesel fulcrum blend ratio and enhanced virility as could be observed in the experiments. The engine with coated piston showed better BTE, less specific fuel consumption and lesser dependency on conventional diesel. Analysis of exhaust emissions further showed that CO reduced, CO2 increased, and unburned HC had decreased but NOx was also increased but kept within permissible limits. The results demonstrate the two-fold advantage of employing Hydrilla biofuel and thermal barrier coating as a collective technique for minimizing fossil fuel dependence and engaging with sustainable engine technologies.
{"title":"Enhance the performance of the thermal barrier coated diesel engine with application of novelly extracted and optimization of aquatic plant-based biofuel blend","authors":"Ramakrishnan Sambasivam, Annamalai Kandasamy","doi":"10.1016/j.csite.2026.107915","DOIUrl":"10.1016/j.csite.2026.107915","url":null,"abstract":"<div><div>Global energy crisis and environmental issues also have encouraged the quest for renewable and sustainable solutions to the traditional fossil fuels. Alternative biofuels based on water plants offer great potential as they are fast growing, do not compete with food crops and produce high biomass. In the present work, an aquatic weed <em>Hydrilla verticillata</em> was examined as a likely feedstock for biodiesel production. Solvent extracted oil by using n-hexane solvent helps in increasing the yield efficiency and fuel quality from Hydrilla plant feedstocks. The thus obtained oil was mixed with diesel in different ratios and experiments were carried out in a compression ignition engine. Prior to the use of this process analysis work done on zirconia material coated (0.5 mm) that is piston for checking the heat transfer of the piston from top to down with help of ANSYS software and also compared without coated engine. Further to enhance combustion and robustness across the blend range, A zirconia-based thermal barrier coated material was applied to the piston crown to increase in-cylinder heat and pressure to retention and minimize heat losses to the bottom of the piston. The zirconia coating promoted the higher Hydrilla–diesel fulcrum blend ratio and enhanced virility as could be observed in the experiments. The engine with coated piston showed better BTE, less specific fuel consumption and lesser dependency on conventional diesel. Analysis of exhaust emissions further showed that CO reduced, CO<sub>2</sub> increased, and unburned HC had decreased but NOx was also increased but kept within permissible limits. The results demonstrate the two-fold advantage of employing Hydrilla biofuel and thermal barrier coating as a collective technique for minimizing fossil fuel dependence and engaging with sustainable engine technologies.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107915"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387454","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 : 2026-04-01Epub Date: 2026-02-23DOI: 10.1016/j.csite.2026.107852
M.S. Faltas , E.A. Ashmawy , M.G. Nashwan , Baraa A. Ahmed , M. El-Sayed
Thermophoretic transport near fluid interfaces governs a wide array of natural and technological processes, yet a unified theoretical framework that simultaneously captures particle-surface slip phenomena and interfacial thermocapillarity has remained absent from the literature. This study bridges that critical gap by developing a semi-analytical framework, solved via the boundary collocation method, to investigate the motion of a spherical particle in a viscous fluid near an immiscible fluid–fluid interface. The model’s novelty lies in its comprehensive integration of thermal creep, mechanical slip, and thermal stress slip at the particle surface with the transformative influence of thermocapillary (Marangoni) flow. Following rigorous validation against established rigid-wall limits, our analysis reveals physical phenomena that fundamentally diverge from classical predictions for solid boundaries. Most notably, strong interfacial thermocapillary flow is shown to counteract the expected hydrodynamic retardation of an insulating particle, even inverting its motion into a regime of net acceleration. Furthermore, our results challenge the traditional view of mechanical slip as a simple drag-reducer, uncovering a non-monotonic dual role where slip initially weakens the thermophoretic drive before its drag-reducing effect becomes dominant. We also demonstrate for the first time that the impact of thermal stress slip can reverse from enhancing to hindering at higher Knudsen numbers, a complex behavior contingent upon the thermal properties of the secondary fluid. These findings establish a more complete physical picture of thermophoresis in multiphase systems, providing a powerful predictive toolset with direct implications for designing advanced thermal precipitators, engineering “smart fluids” with tunable transport properties, and fabricating novel composite materials through the controlled deposition of particles at interfaces.
{"title":"Coupled thermophoretic and thermocapillary effects on the motion of a particle near an immiscible fluid interface","authors":"M.S. Faltas , E.A. Ashmawy , M.G. Nashwan , Baraa A. Ahmed , M. El-Sayed","doi":"10.1016/j.csite.2026.107852","DOIUrl":"10.1016/j.csite.2026.107852","url":null,"abstract":"<div><div>Thermophoretic transport near fluid interfaces governs a wide array of natural and technological processes, yet a unified theoretical framework that simultaneously captures particle-surface slip phenomena and interfacial thermocapillarity has remained absent from the literature. This study bridges that critical gap by developing a semi-analytical framework, solved via the boundary collocation method, to investigate the motion of a spherical particle in a viscous fluid near an immiscible fluid–fluid interface. The model’s novelty lies in its comprehensive integration of thermal creep, mechanical slip, and thermal stress slip at the particle surface with the transformative influence of thermocapillary (Marangoni) flow. Following rigorous validation against established rigid-wall limits, our analysis reveals physical phenomena that fundamentally diverge from classical predictions for solid boundaries. Most notably, strong interfacial thermocapillary flow is shown to counteract the expected hydrodynamic retardation of an insulating particle, even inverting its motion into a regime of net acceleration. Furthermore, our results challenge the traditional view of mechanical slip as a simple drag-reducer, uncovering a non-monotonic dual role where slip initially weakens the thermophoretic drive before its drag-reducing effect becomes dominant. We also demonstrate for the first time that the impact of thermal stress slip can reverse from enhancing to hindering at higher Knudsen numbers, a complex behavior contingent upon the thermal properties of the secondary fluid. These findings establish a more complete physical picture of thermophoresis in multiphase systems, providing a powerful predictive toolset with direct implications for designing advanced thermal precipitators, engineering “smart fluids” with tunable transport properties, and fabricating novel composite materials through the controlled deposition of particles at interfaces.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107852"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147278947","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 : 2026-04-01Epub Date: 2026-02-27DOI: 10.1016/j.csite.2026.107871
Pouya Nikpendar, Omid Jahanian, Davood Domiri Ganji, Mohammad Mohsen Peiravi
As oil fields and steam power plants develop further, the separation of gas particles and liquid droplets presents significant challenges. Cyclone separators, as a type of high-efficiency and low-volume separators, are widely used in the separation of gas-liquid flows. In this study, the steady-state performance of the cyclone separator under pulsed and turbulent flow conditions at the outlet of two-phase gas-liquid cylindrical cyclones was simulated using three-dimensional discrete phase model and validated with experimental results from the cyclone constructed. The effect of pulsating output and turbulent flow fluctuations on the separation efficiency and the reduction of unwanted phenomena of gas transport from the lower outlet and liquid transport from the upper outlet were investigated. The innovation in the geometry of these separators were experimentally evaluated and the effect of various geometric parameters including the length of the cyclone below the inlet, the length of the cyclone above the inlet, the diameter of the cyclone and the frequency of the outlet valve were analyzed. Through systematic experimentation and numerical analysis, in addition to reducing the gas carry-under value to zero, the best upper and lower pipe heights of 400 and 1300 mm, respectively, and the best upper outlet diameter of 40 mm were achieved. Also, in addition to reducing the gas carry-under value to zero and controlling the liquid carry-over value through the separation process under the pulse pressure range at an optimal frequency, the best closing and opening times of the pulse outlet valve were 3 and 1 s, respectively.
{"title":"Sustainable separation system for pulsating and multiphase turbulent flow in gas-liquid cylindrical cyclone","authors":"Pouya Nikpendar, Omid Jahanian, Davood Domiri Ganji, Mohammad Mohsen Peiravi","doi":"10.1016/j.csite.2026.107871","DOIUrl":"10.1016/j.csite.2026.107871","url":null,"abstract":"<div><div>As oil fields and steam power plants develop further, the separation of gas particles and liquid droplets presents significant challenges. Cyclone separators, as a type of high-efficiency and low-volume separators, are widely used in the separation of gas-liquid flows. In this study, the steady-state performance of the cyclone separator under pulsed and turbulent flow conditions at the outlet of two-phase gas-liquid cylindrical cyclones was simulated using three-dimensional discrete phase model and validated with experimental results from the cyclone constructed. The effect of pulsating output and turbulent flow fluctuations on the separation efficiency and the reduction of unwanted phenomena of gas transport from the lower outlet and liquid transport from the upper outlet were investigated. The innovation in the geometry of these separators were experimentally evaluated and the effect of various geometric parameters including the length of the cyclone below the inlet, the length of the cyclone above the inlet, the diameter of the cyclone and the frequency of the outlet valve were analyzed. Through systematic experimentation and numerical analysis, in addition to reducing the gas carry-under value to zero, the best upper and lower pipe heights of 400 and 1300 mm, respectively, and the best upper outlet diameter of 40 mm were achieved. Also, in addition to reducing the gas carry-under value to zero and controlling the liquid carry-over value through the separation process under the pulse pressure range at an optimal frequency, the best closing and opening times of the pulse outlet valve were 3 and 1 s, respectively.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107871"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330093","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 : 2026-04-01Epub Date: 2026-02-26DOI: 10.1016/j.csite.2026.107868
Hassan Raza Shah , Shangqing Tao , Jun Fang , Jingwu Wang , Xuqing Lang , Zhi Jian Tian
Water mist systems for fire protection are widely recognized for their ability to attenuate thermal radiation and suppress fires. This study used high-precision shadow imaging with a non-luminous radiant panel to investigate the water mist droplet evolution and distribution under varying nozzle pressures and radiant panel temperatures (i.e., ambient thermal conditions), and their effects on thermal radiation attenuation (TRA). Under non-thermal conditions, droplet growth with distance was dominated by coalescence, while under thermal exposure, both evaporation and coalescence were observed, with pressure governing the dominant mechanism: at low pressure, droplets transitioned from evaporation-dominant to a combination of evaporation and coalescence, whereas at high pressure, the mechanism sequence was reversed. A radiation-driven critical distance based on characteristic droplet size (CDS) and size variance distribution parameter (σ) was identified, beyond which the dominant mechanism changed. A simplified theoretical equation, validated against experiments, reproduced droplet size and velocity evolution, revealing the coupled mechanism arising from size variation with distance. Furthermore, the water mist radiation protection was significantly influenced by radiant panel temperature, thereby altering TRA. These findings provide theoretical and experimental insights for advancements of efficient water-mist technologies for thermal radiation protection and fire suppression.
{"title":"Effect of droplet size evolution and distribution of water mist on the thermal radiation attenuation","authors":"Hassan Raza Shah , Shangqing Tao , Jun Fang , Jingwu Wang , Xuqing Lang , Zhi Jian Tian","doi":"10.1016/j.csite.2026.107868","DOIUrl":"10.1016/j.csite.2026.107868","url":null,"abstract":"<div><div>Water mist systems for fire protection are widely recognized for their ability to attenuate thermal radiation and suppress fires. This study used high-precision shadow imaging with a non-luminous radiant panel to investigate the water mist droplet evolution and distribution under varying nozzle pressures and radiant panel temperatures (<em>i.e.</em>, ambient thermal conditions), and their effects on thermal radiation attenuation (TRA). Under non-thermal conditions, droplet growth with distance was dominated by coalescence, while under thermal exposure, both evaporation and coalescence were observed, with pressure governing the dominant mechanism: at low pressure, droplets transitioned from evaporation-dominant to a combination of evaporation and coalescence, whereas at high pressure, the mechanism sequence was reversed. A radiation-driven critical distance based on characteristic droplet size (CDS) and size variance distribution parameter (σ) was identified, beyond which the dominant mechanism changed. A simplified theoretical equation, validated against experiments, reproduced droplet size and velocity evolution, revealing the coupled mechanism arising from size variation with distance. Furthermore, the water mist radiation protection was significantly influenced by radiant panel temperature, thereby altering TRA. These findings provide theoretical and experimental insights for advancements of efficient water-mist technologies for thermal radiation protection and fire suppression.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107868"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330096","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 : 2026-04-01Epub Date: 2026-03-04DOI: 10.1016/j.csite.2026.107895
Maojun Xu , Yao Qin , Tingyi Ouyang , Bei Liu , Jinxin Liu , Jia Geng , Huihui Miao , Minglong Du , Zhiping Song
Turbine exit total temperature (Tt6) is a critical yet challenging parameter to measure directly in aero-engines due to extreme thermal conditions that often lead to sensor faults like drift, threatening engine safety and efficiency. Virtual sensing provides a viable alternative, but prevailing data-driven methods, typically reliant on the mean squared error (MSE) loss, suffer from performance degradation under non-Gaussian noise and sensor anomalies. To overcome this limitation, this paper introduces a robust virtual sensing framework based on a novel Truncated Generalized Correntropy loss. By integrating the generalized maximum correntropy criterion with an adaptive truncation mechanism, the proposed loss function effectively suppresses the influence of outliers and faulty measurements. Embedded into an Extreme Learning Machine (ELM), this yields the Robust Truncated Generalized Correntropy ELM (RTGC-ELM) algorithm. The framework was rigorously validated using high-fidelity component-level model data under realistic flight profiles and further tested on the public NASA C-MAPSS dataset. Evaluations covered both normal operations and severe sensor fault scenarios (step-type and ramp-type drift). The results demonstrate that RTGC-ELM maintains high accuracy under normal conditions (MAE ∼1.21%) while exhibiting exceptional robustness under faults. For instance, under a step-type fault, RTGC-ELM limited performance degradation to only 0.01% (MAE increase from 1.21% to 1.22%), significantly outperforming conventional ELM (MAE increase from 1.28% to 1.75%) and other algorithms. This superior robustness was consistent across fault types and severity levels, confirmed through statistical significance tests and cross-dataset validation. The proposed RTGC-ELM provides a robust, efficient, and practical solution for analytical redundancy in aero-engine health management systems.
{"title":"Robust virtual sensing of turbine exit temperature for aero-engines using a truncated generalized correntropy-based extreme learning machine","authors":"Maojun Xu , Yao Qin , Tingyi Ouyang , Bei Liu , Jinxin Liu , Jia Geng , Huihui Miao , Minglong Du , Zhiping Song","doi":"10.1016/j.csite.2026.107895","DOIUrl":"10.1016/j.csite.2026.107895","url":null,"abstract":"<div><div>Turbine exit total temperature (<em>T</em><sub>t6</sub>) is a critical yet challenging parameter to measure directly in aero-engines due to extreme thermal conditions that often lead to sensor faults like drift, threatening engine safety and efficiency. Virtual sensing provides a viable alternative, but prevailing data-driven methods, typically reliant on the mean squared error (MSE) loss, suffer from performance degradation under non-Gaussian noise and sensor anomalies. To overcome this limitation, this paper introduces a robust virtual sensing framework based on a novel Truncated Generalized Correntropy loss. By integrating the generalized maximum correntropy criterion with an adaptive truncation mechanism, the proposed loss function effectively suppresses the influence of outliers and faulty measurements. Embedded into an Extreme Learning Machine (ELM), this yields the Robust Truncated Generalized Correntropy ELM (RTGC-ELM) algorithm. The framework was rigorously validated using high-fidelity component-level model data under realistic flight profiles and further tested on the public NASA C-MAPSS dataset. Evaluations covered both normal operations and severe sensor fault scenarios (step-type and ramp-type drift). The results demonstrate that RTGC-ELM maintains high accuracy under normal conditions (MAE ∼1.21%) while exhibiting exceptional robustness under faults. For instance, under a step-type fault, RTGC-ELM limited performance degradation to only 0.01% (MAE increase from 1.21% to 1.22%), significantly outperforming conventional ELM (MAE increase from 1.28% to 1.75%) and other algorithms. This superior robustness was consistent across fault types and severity levels, confirmed through statistical significance tests and cross-dataset validation. The proposed RTGC-ELM provides a robust, efficient, and practical solution for analytical redundancy in aero-engine health management systems.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107895"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147359836","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 : 2026-04-01Epub Date: 2026-03-06DOI: 10.1016/j.csite.2026.107896
Yuliang Sun , Xuehua Li , Yanzi Lei , Hongtao An , Kaipeng Wang , Qiang Yu
Deep mining is the primary direction for future mine development. However, deep mining causes heat damage, which seriously affects work efficiency and worker health. To satisfy the requirements of thermal comfort, a two-stage desiccant wheel dehumidification deep mine cooling system driven by mine water source heat pump (TSDW-DMCS-MWSHP) is proposed. The system consists of a two-stage desiccant wheel, water source heat pump, air cooler, and air heater. A water source heat pump is used to realize the dual supply of cold and heat, which provides cold and heat sources for cooling the mine airflow and heating the regeneration air. A two-stage desiccant wheel is used to achieve deep dehumidification. A heat and mass transfer model of the system is established and simulated. The effects of the main operating parameters on energy, dehumidification, and exergy performances are systematically investigated. The results show that when the inlet temperature of the mine airflow is 32 °C and the relative humidity is 80 %, the system can achieve a temperature difference of 6 °C, a humidity ratio difference of 11.7 g/kg, and an enthalpy difference of 36.1 kJ/kg. When the two-stage desiccant wheel operates at a low regeneration temperature of 60 °C, the TCOP, DCOP, and exergy efficiency reach their peak values of 2.8, 0.9, and 68.9 %, respectively. Compared with the ground centralized refrigeration system, the supply air relative humidity of the TSDW-DMCS-MWSHP is reduced by 13.3 %, and the COP is increased by 16 %. The TSDW-DMCS-MWSHP offers a viable solution for mitigating mine heat damage and advancing the sustainable development in the mining industry.
{"title":"Study on a two-stage desiccant wheel dehumidification deep mine cooling system driven by mine water source heat pump","authors":"Yuliang Sun , Xuehua Li , Yanzi Lei , Hongtao An , Kaipeng Wang , Qiang Yu","doi":"10.1016/j.csite.2026.107896","DOIUrl":"10.1016/j.csite.2026.107896","url":null,"abstract":"<div><div>Deep mining is the primary direction for future mine development. However, deep mining causes heat damage, which seriously affects work efficiency and worker health. To satisfy the requirements of thermal comfort, a two-stage desiccant wheel dehumidification deep mine cooling system driven by mine water source heat pump (TSDW-DMCS-MWSHP) is proposed. The system consists of a two-stage desiccant wheel, water source heat pump, air cooler, and air heater. A water source heat pump is used to realize the dual supply of cold and heat, which provides cold and heat sources for cooling the mine airflow and heating the regeneration air. A two-stage desiccant wheel is used to achieve deep dehumidification. A heat and mass transfer model of the system is established and simulated. The effects of the main operating parameters on energy, dehumidification, and exergy performances are systematically investigated. The results show that when the inlet temperature of the mine airflow is 32 °C and the relative humidity is 80 %, the system can achieve a temperature difference of 6 °C, a humidity ratio difference of 11.7 g/kg, and an enthalpy difference of 36.1 kJ/kg. When the two-stage desiccant wheel operates at a low regeneration temperature of 60 °C, the <em>TCOP</em>, <em>DCOP</em>, and exergy efficiency reach their peak values of 2.8, 0.9, and 68.9 %, respectively. Compared with the ground centralized refrigeration system, the supply air relative humidity of the TSDW-DMCS-MWSHP is reduced by 13.3 %, and the COP is increased by 16 %. The TSDW-DMCS-MWSHP offers a viable solution for mitigating mine heat damage and advancing the sustainable development in the mining industry.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107896"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387374","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 : 2026-04-01Epub Date: 2026-02-19DOI: 10.1016/j.csite.2026.107821
Jie Zhang , Wangru Yang , Shusheng Gao , Jinmei Peng , Feifei Fang , Zhenkai Wu , Ye Zhang , Xiaoliang Huang , Zhilin Qi
Water lock in the near-wellbore region severely constrains the productivity of tight sandstone gas reservoirs. Unlike conventional methods limited by high energy costs and secondary pollution, microwave heating offers a high-efficiency alter native capable of simultaneously reducing flow resistance and inducing fracture-enhanced permeability. This study investigates these mechanisms using Sulige sandstone cores through a combination of CT scanning, XRD, physical experiments, and coupled thermo-hydro-mechanical simulations. Key findings include: (1) Microwave radiation induces pore water vaporization and thermal stress fracturing, significantly improving pore connectivity once a temperature threshold of 500 °C is surpassed. (2) Under optimal conditions (800 W, 15min), the stable production period extended by 23–48 times, and ultimate recovery improved by approximately 20–26% across varying water saturations. (3) Numerical modeling, exhibiting high agreement with experimental data, predicts an effective remediation radius of 0.6 m and a total gas production increase of 0.34 × 106 m3. These results confirm the efficacy of microwave heating in alleviating water lock, offering a robust theoretical and technical basis for optimizing field development strategies.
{"title":"Research on the mechanism of water lock removal in tight sandstone gas reservoirs under microwave radiation","authors":"Jie Zhang , Wangru Yang , Shusheng Gao , Jinmei Peng , Feifei Fang , Zhenkai Wu , Ye Zhang , Xiaoliang Huang , Zhilin Qi","doi":"10.1016/j.csite.2026.107821","DOIUrl":"10.1016/j.csite.2026.107821","url":null,"abstract":"<div><div>Water lock in the near-wellbore region severely constrains the productivity of tight sandstone gas reservoirs. Unlike conventional methods limited by high energy costs and secondary pollution, microwave heating offers a high-efficiency alter native capable of simultaneously reducing flow resistance and inducing fracture-enhanced permeability. This study investigates these mechanisms using Sulige sandstone cores through a combination of CT scanning, XRD, physical experiments, and coupled thermo-hydro-mechanical simulations. Key findings include: (1) Microwave radiation induces pore water vaporization and thermal stress fracturing, significantly improving pore connectivity once a temperature threshold of 500 °C is surpassed. (2) Under optimal conditions (800 W, 15min), the stable production period extended by 23–48 times, and ultimate recovery improved by approximately 20–26% across varying water saturations. (3) Numerical modeling, exhibiting high agreement with experimental data, predicts an effective remediation radius of 0.6 m and a total gas production increase of 0.34 × 10<sup>6</sup> m<sup>3</sup>. These results confirm the efficacy of microwave heating in alleviating water lock, offering a robust theoretical and technical basis for optimizing field development strategies.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107821"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146777433","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 : 2026-04-01Epub Date: 2026-02-28DOI: 10.1016/j.csite.2026.107850
Muhammad Sabeel Khan , A. Al-Zubaidi , Noor-ul Absar , M. Asif Memon , Amsalu Fenta
This study investigates heat and mass transfer in a square porous cavity containing oxytactic microorganisms using the Cattaneo–Christov heat flux model and Darcy flow. The governing equations, which incorporate the laws of mass, momentum, and energy conservation, are solved numerically using the finite-element method. Strong agreement is found when the Nusselt and Sherwood values are calculated and compared with the data provided in the black literature to validate the results. The results are calculated and thoroughly presented for a range of values of the physical parameters. Using streamlines, isotherms, concentration profiles and tables, the results show how different parameters like the Lewis number, the Peclet number, the Rayleigh number, and the bioconvection Rayleigh number affect heat and mass transfer with oxytactic microorganisms in the cavity. The cavity’s side walls further highlight how these characteristics affect the Nusselt and Sherwood numbers. With an emphasis on the influence of important physical parameters, the study often offers valuable information about the intricate relationships between heat, fluid flow, and microbe concentration within a porous cavity. It is observed that when the Péclet number increases from the baseline case of 0.1 to 13, the maximum value of the stream function increases by approximately 44. 2%, clearly highlighting the sensitivity of the flow field to variations in the advection strength. Similarly, as the Péclet number increases from 1 to 29, the minimum oxygen concentration decreases by almost 16.1%, indicating substantial oxygen depletion at higher Péclet values. An increase in the relaxation parameter from 0 to 2.55 results in a reduction of 41. 3% in the maximum value of the stream function, demonstrating the significant suppressive effect of relaxation on the convective strength of the flow. The presence of microorganisms improves heat transfer, with the Nusselt number increasing by approximately 15%–20% at low Prandtl numbers and exceeding 30% at higher Prandtl numbers, indicating a synergistic interaction between thermal stratification and bioconvection. Furthermore, as the oxygen consumption parameter increases, the minimum oxygen concentration is reduced by almost 12. 9%, indicating the dominant role of consumption over diffusion in shaping oxygen distribution within the cavity. These results are crucial to improve heat transmission and bioconvection processes in porous media, especially biological or ecological systems where microorganisms are important to dynamics.
{"title":"Thermo-bioconvective transport in an oxytactic microorganisms-laden cavity","authors":"Muhammad Sabeel Khan , A. Al-Zubaidi , Noor-ul Absar , M. Asif Memon , Amsalu Fenta","doi":"10.1016/j.csite.2026.107850","DOIUrl":"10.1016/j.csite.2026.107850","url":null,"abstract":"<div><div>This study investigates heat and mass transfer in a square porous cavity containing oxytactic microorganisms using the Cattaneo–Christov heat flux model and Darcy flow. The governing equations, which incorporate the laws of mass, momentum, and energy conservation, are solved numerically using the finite-element method. Strong agreement is found when the Nusselt and Sherwood values are calculated and compared with the data provided in the black literature to validate the results. The results are calculated and thoroughly presented for a range of values of the physical parameters. Using streamlines, isotherms, concentration profiles and tables, the results show how different parameters like the Lewis number, the Peclet number, the Rayleigh number, and the bioconvection Rayleigh number affect heat and mass transfer with oxytactic microorganisms in the cavity. The cavity’s side walls further highlight how these characteristics affect the Nusselt and Sherwood numbers. With an emphasis on the influence of important physical parameters, the study often offers valuable information about the intricate relationships between heat, fluid flow, and microbe concentration within a porous cavity. It is observed that when the Péclet number increases from the baseline case of 0.1 to 13, the maximum value of the stream function increases by approximately 44. 2%, clearly highlighting the sensitivity of the flow field to variations in the advection strength. Similarly, as the Péclet number increases from 1 to 29, the minimum oxygen concentration decreases by almost 16.1%, indicating substantial oxygen depletion at higher Péclet values. An increase in the relaxation parameter from 0 to 2.55 results in a reduction of 41. 3% in the maximum value of the stream function, demonstrating the significant suppressive effect of relaxation on the convective strength of the flow. The presence of microorganisms improves heat transfer, with the Nusselt number increasing by approximately 15%–20% at low Prandtl numbers and exceeding 30% at higher Prandtl numbers, indicating a synergistic interaction between thermal stratification and bioconvection. Furthermore, as the oxygen consumption parameter increases, the minimum oxygen concentration is reduced by almost 12. 9%, indicating the dominant role of consumption over diffusion in shaping oxygen distribution within the cavity. These results are crucial to improve heat transmission and bioconvection processes in porous media, especially biological or ecological systems where microorganisms are important to dynamics.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107850"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330092","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}
To facilitate the effective design of supercritical fluid (SCF) processes aimed at micro- or nanosizing solid pharmaceuticals, obtaining solubility data in environmentally friendly solvents such as pressurized carbon dioxide (CO2) is essential. Solubility assessment represents a critical first step in evaluating SCF technologies. This study introduces a statistical methodology to experimentally determine the solubility of paclitaxel (Pac) in supercritical CO2. UV-vis spectrophotometric studies were carried out under pressures ranging from 120 to 270 bar and temperatures ranging from 308 to 338 K. Three distinct modeling approaches were used to predict and correlate the experimentally determined solubility of paclitaxel: (i) a collection of six density-based empirical models; (ii) a hybrid of the Peng-Robinson (PR) equation of state and the van der Waals quadratic mixing rule; and (iii) machine learning procedures, including fifteen non-linear regressions. A solubility range of 0.0017 to 0.077 g/L was observed for paclitaxel. At a steady temperature, the paclitaxel mole fraction increased as the pressure rose, albeit a crossover occurrence was noted. While all methods achieved adequate levels of correlation accuracy, the Méndez-Santiago & Teja (MT) model outperformed the others in terms of predictive power, with an AARD of only 4.06%. For the first time semi-empirical correlations were used to estimate the paclitaxel/Sc-CO2 system enthalpies as = 28.04 kJ/mol, = −19.11 kJ/mol, and, = 47.15 kJ/mol.
{"title":"Determination of paclitaxel anticancer drug solubility in supercritical CO2: Thermodynamics modeling and machine learning approach","authors":"Gholamhossein Sodeifian , Ratna Surya Alwi , Nedasadat Saadati Ardestani , Adel Noubigh , Reza Derakhsheshpour , Amir Elyasi","doi":"10.1016/j.csite.2026.107864","DOIUrl":"10.1016/j.csite.2026.107864","url":null,"abstract":"<div><div>To facilitate the effective design of supercritical fluid (SCF) processes aimed at micro- or nanosizing solid pharmaceuticals, obtaining solubility data in environmentally friendly solvents such as pressurized carbon dioxide (CO<sub>2</sub>) is essential. Solubility assessment represents a critical first step in evaluating SCF technologies. This study introduces a statistical methodology to experimentally determine the solubility of paclitaxel (Pac) in supercritical CO<sub>2</sub>. UV-vis spectrophotometric studies were carried out under pressures ranging from 120 to 270 bar and temperatures ranging from 308 to 338 K. Three distinct modeling approaches were used to predict and correlate the experimentally determined solubility of paclitaxel: (i) a collection of six density-based empirical models; (ii) a hybrid of the Peng-Robinson (PR) equation of state and the van der Waals quadratic mixing rule; and (iii) machine learning procedures, including fifteen non-linear regressions. A solubility range of 0.0017 to 0.077 g/L was observed for paclitaxel. At a steady temperature, the paclitaxel mole fraction increased as the pressure rose, albeit a crossover occurrence was noted. While all methods achieved adequate levels of correlation accuracy, the Méndez-Santiago & Teja (MT) model outperformed the others in terms of predictive power, with an AARD of only 4.06%. For the first time semi-empirical correlations were used to estimate the paclitaxel/Sc-CO<sub>2</sub> system enthalpies as <span><math><mrow><msub><mrow><mo>Δ</mo><mi>H</mi></mrow><mtext>tot</mtext></msub></mrow></math></span> = 28.04 kJ/mol, <span><math><mrow><msub><mrow><mo>Δ</mo><mi>H</mi></mrow><mtext>sol</mtext></msub></mrow></math></span> = −19.11 kJ/mol, and, <span><math><mrow><msub><mrow><mo>Δ</mo><mi>H</mi></mrow><mtext>vap</mtext></msub></mrow></math></span> = 47.15 kJ/mol.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107864"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330099","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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