Case Studies in Thermal Engineering最新文献

{"title":"The experimental study of compressed air foam produced by 2-bromo-3,3,3-trifluoro-propene and air in suppression of 1 m2 n-pentane oil fire","authors":"Tao Chen ,&nbsp;Junyi Zhang ,&nbsp;Lishuai Jing ,&nbsp;Yi Li ,&nbsp;Qihang Yue ,&nbsp;Peng Zhang ,&nbsp;Biao Zhou","doi":"10.1016/j.csite.2025.105900","DOIUrl":"10.1016/j.csite.2025.105900","url":null,"abstract":"<div><div>In this paper, an experimental model of a 1 m² tank fire was constructed to investigate the coupling mechanism between 2-bromo-3,3,3-trifluoro-propene (BTP) and the compressed air foam system (CAFS), and to optimize the extinguishing performance of the combination of extinguishing agents by controlling the flow rate of BTP. The results demonstrated that the combination of compressed air foam (CAF) and BTP significantly enhances the foam's performance on low-boiling point flammable liquids. It is found that, in Test No.3, the fire control time of the aqueous film-forming foam (AFFF) and BTP was about two times higher than the extinguishing time of CAF with the same supply strength. In Test No.2, the fire control and extinguishing time of the alcohol-resistant aqueous film-forming foam (AFFF/AR) and BTP was about 20 % higher than that of CAF. After the formula was calculated, it gave the BTP gasification rates range from 0.26 to 0.73, and the volume share of BTP vapor ranges from 12.77 % to 53.77 %. And the BTP vapor percentage in the foam reaches a certain value, the physical and chemical extinguishing effects are coupled. The effectiveness of fire suppression is increased. This study offers a novel technical approach for the low-boiling point flammable liquid fires, carrying important implications for engineering applications.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105900"},"PeriodicalIF":6.4,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438258","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}

{"title":"Influence of flat tube aspect ratio on melting characteristics of phase change material within a double-tube unit","authors":"Gwan Gyu Kim ,&nbsp;Chan Woo An ,&nbsp;Young Min Seo ,&nbsp;Seokho Kim ,&nbsp;Hoon Ki Choi ,&nbsp;Yong Gap Park","doi":"10.1016/j.csite.2025.105892","DOIUrl":"10.1016/j.csite.2025.105892","url":null,"abstract":"<div><div>In this study, a numerical analysis was performed to investigate how the aspect ratio of flat tubes in a double-tube latent thermal energy storage system affects the melting behavior and thermal transfer properties of N-eicosane. To simulate the melting characteristics of the systems, the enthalpy–porosity method was employed. The aspect ratios of flat tubes in the inner and outer configurations significantly affected the melting characteristics. A smaller aspect ratio of the inner flat tube (AR_i) increased natural convection, resulting in a decreased total melting time. Conversely, a larger aspect ratio of the outer flat tube (AR_o) decreased the amount of solid PCM remaining, which also contributed to a shorter total melting time. For instance, in case 13, the total melting time was 1223.5 s, which represents a 59.3 % reduction compared with case 46, i.e., the base case with circular double tubes. The mean power in case 13 was 261.2 W, which corresponded to an increase of 146.08 % compared with the base case. Furthermore, at the optimal performance of AR_o = 1.8, correlation equations for total melting time and mean power were derived to assess the influence of AR_i regarding the melting process of systems.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105892"},"PeriodicalIF":6.4,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446151","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}

{"title":"Thermal analysis of non-Newtonian fluid with radiation and MHD effects over permeable exponential stretching sheet","authors":"Nadeem Abbas ,&nbsp;Wasfi Shatanawi ,&nbsp;Zead Mustafa","doi":"10.1016/j.csite.2025.105895","DOIUrl":"10.1016/j.csite.2025.105895","url":null,"abstract":"<div><div>In our recent analysis, we investigated the 3-D flow of a second-grade fluid over an exponentially stretching sheet, taking into account the variable viscosity and thermal conductivity of the fluid. We also considered the influences of a magnetic field and the characteristics of a permeable exponential stretching sheet under thermal slip condition. Furthermore, we explored the phenomena of radiation and heat generation. The governing flow system has been mathematically formulated, and boundary layer approximations are used to make simpler the differential equations. By applying appropriate transformations, we reduced the differential equations into a dimensionless (ordinary differential equations) system of equations. We then employed a numerical scheme to solve the dimensionless system, presenting the numerical results in tabular and graphical formats. Through these graphical and numerical results, we discussed the influence of several physical phenomena on the flow and examined how different parameters affected the behavior of the system. Velocity profile decreased with growing values of the magnetic field factor. As a result of the fluid encountering more flow resistance, the velocity profile become lesser. The temperature curves are seen to increase by enlarging values of heat generation.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105895"},"PeriodicalIF":6.4,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446152","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}

{"title":"Experimental study and correlation analysis on thermal storage oxidation of ventilation air methane mixed with pulverized coal","authors":"Hao Zhang ,&nbsp;Baisheng Nie ,&nbsp;Guofu Li ,&nbsp;Xianfeng Liu ,&nbsp;Feifei Yin ,&nbsp;Zheng Wang ,&nbsp;Hengyi He ,&nbsp;Song Bao ,&nbsp;Haolun Fu ,&nbsp;Jijiang Huang","doi":"10.1016/j.csite.2025.105885","DOIUrl":"10.1016/j.csite.2025.105885","url":null,"abstract":"<div><div>The recovery and utilization of ventilation air methane (VAM) are critical for advancing green, low-carbon and sustainable development. This study aims to address the challenge associated with the low concentration of VAM, which hampers its effective utilization. A self-constructed experimental system was employed in which VAM was blended with pulverized coal for thermal storage and oxidation. This system was used to evaluate the effects of key process parameters, including initial temperature, concentration, and flow rate. The results indicate that the blending of pulverized coal significantly increases the VAM conversion rate and extends the duration of stable conversion. However, while the stabilization time of the regenerative reaction was prolonged, an increase in flow rate had the opposite effect. Furthermore, the VAM conversion rate exhibited a positive correlation with the self-sustaining stable time of the reaction, with initial temperature showing the strongest influence on the conversion rate. This study provides valuable insights into the thermal oxidation and storage of VAM doped with pulverized coal, offering a clear path forward for the large-scale utilization of VAM for thermal storage.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105885"},"PeriodicalIF":6.4,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429676","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}

{"title":"Exploring interfacial solar evaporation heat transfer mechanisms of photothermal solar still systems","authors":"Milad Haghighat ,&nbsp;Mohammad Mahdi Entezarian ,&nbsp;Mohsen Salimi ,&nbsp;Majid Amidpour","doi":"10.1016/j.csite.2025.105883","DOIUrl":"10.1016/j.csite.2025.105883","url":null,"abstract":"<div><div>The growing global demand for freshwater, coupled with the scarcity of freshwater resources and the environmental concerns associated with fossil fuel-based water desalination, necessitates innovative approaches to freshwater production. This paper presents a novel method for desalinating water using renewable energy sources. The proposed method involves the use of a glass chamber with a sloping roof, filled with seawater of 3.5 % salt concentration, and covered with porous filaments. These filaments facilitate the absorption of saltwater, promote air circulation, and harness solar radiation within the chamber, thereby enhancing the process of saltwater absorption and evaporation. The evaporated water vapor condenses on the sloping glass roof, and the external airflow cools the water, leading to the collection of freshwater droplets at the bottom of the chamber. This solar-powered desalination device offers a sustainable solution for regions lacking access to freshwater resources or during emergencies requiring immediate access to freshwater.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105883"},"PeriodicalIF":6.4,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438257","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}

{"title":"Significance of aspect ratio of internal heating element in optimizing thermal production of water with ternary nano composition in crown chamber","authors":"S. Bilal ,&nbsp;Imtiaz Ali Shah ,&nbsp;A.S. Alqahtani ,&nbsp;M.Y. Malik","doi":"10.1016/j.csite.2025.105882","DOIUrl":"10.1016/j.csite.2025.105882","url":null,"abstract":"<div><div>Enhancing the thermodynamic performance of systems including thermal exchanging devices, solar collectors, and thermally controlled instruments is crucial for industrial advancements. This investigation probes the thermal performance of water in a crown-shaped chamber infused with Cu-CuO-Al₂O₃ ternary hybrid nanoparticles. Unlike previous studies focusing on simpler geometries and binary nanofluids, this work introduces a novel chamber design with a heating element of varying aspect ratios with magnetic field effectiveness. The governing equations are modeled using partial differential equations, incorporating the thermophysical characteristics of the ternary nanofluid. Finite element simulations are performed in COMSOL Multiphysics, with mesh independence verified. Results show a remarkable 360 % upsurge in the average thermal flux, highlighting the superior heat transfer capabilities of ternary nanofluids and the influence of advanced geometrical designs. These findings emphasize the potential of ternary nanofluids in optimizing thermal systems.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105882"},"PeriodicalIF":6.4,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453462","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}

{"title":"Thermal performance and entropy generation analysis of hybrid nanofluids in a 3D cylindrical microtube: Implications for biomedical applications","authors":"Chenxu Duan ,&nbsp;Hassan Roshani ,&nbsp;Payam Jalili ,&nbsp;Bahram Jalili ,&nbsp;Irshad Ahmad ,&nbsp;Qasem M Al-Mdallal ,&nbsp;Pan Zhang","doi":"10.1016/j.csite.2025.105873","DOIUrl":"10.1016/j.csite.2025.105873","url":null,"abstract":"<div><div>This study presents a numerical analysis of transient natural convection, heat transfer, and entropy generation in a 3D cylindrical microtube containing a hybrid nanofluid with potential applications in biomedical engineering, such as targeted drug delivery and microfluidic heat exchangers. The analysis spans the time interval of 0 ≤ t ≤ 1.5 s and is based on dimensionless parameters, including Reynolds number, Richardson number, nanoparticle volume fraction, and Prandtl number. The hybrid nanofluid, composed of Al₂O₃ (5 %) and Cu (3 %) nanoparticles suspended in water, enhances flow and heat transfer characteristics, making it suitable for high-precision thermal management in micro-scale biomedical systems. Galerkin's finite element method is employed to solve the governing equations for flow behavior, temperature distribution, and entropy generation. Results indicate that increasing Reynolds and Richardson numbers intensifies flow and enhances velocity magnitudes, which is crucial for optimizing drug transport and thermal efficiency in microdevices. Additionally, entropy generation decreases with increasing Richardson number but rises with Reynolds number, while the average Nusselt number improves with both parameters, ensuring effective heat transfer performance in medical devices.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105873"},"PeriodicalIF":6.4,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453459","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}

{"title":"Supply-demand matching analysis of solar energy systems integrated with ASHP utilization in residential buildings with various time scale","authors":"Min Chen ,&nbsp;Sijia Qiao","doi":"10.1016/j.csite.2025.105859","DOIUrl":"10.1016/j.csite.2025.105859","url":null,"abstract":"<div><div>The optimization of the matching relationship between solar energy supply and building energy demand is crucial for enhancing solar energy utilization in buildings. In this study, models of solar photothermal integrated heat pump (PT-ASHP) and solar photovoltaic integrated heat pump (PV-ASHP) systems were established, with a single air source heat pump (ASHP-only) system as a benchmark, based on their implementation in a six-story residential building located in Wuhan. Energy supply-demand matching analysis was conducted at three different time scales using indicators such as On-site energy fraction and On-site energy matching, to evaluate the influence of climate conditions on the thermal and electrical efficiency of the solar energy system. Furthermore, economic and environmental comparisons were made among PT-ASHP, PV-ASHP, and ASHP-only systems. The results showed that the PV-ASHP system had excellent performance with a coefficient of performance of 3.38 and achieved the lowest annual operating cost. Additionally, both PT-ASHP and PV-ASHP systems reduced annual operating costs by 4936.96 CNY and 6980 CNY respectively compared to the ASHP-only system. The PV-ASHP system also exhibited a higher primary energy saving ratio of 22 %, while the PT-ASHP system reduced electricity purchased from the grid resulting in better carbon emissions reduction up to 38.66 tons.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105859"},"PeriodicalIF":6.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419086","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}

{"title":"Revealing the heat transfer enhancement mechanism of dimpled tube hybridized with twisted tape via dimple utility indicator","authors":"Jinyi Liu ,&nbsp;Jiayu Sun ,&nbsp;Chuqin Yin ,&nbsp;Chuntao Wang ,&nbsp;Jie Sun","doi":"10.1016/j.csite.2025.105867","DOIUrl":"10.1016/j.csite.2025.105867","url":null,"abstract":"<div><div>The dimpled tube has long been recognized as an effective method for enhancing heat transfer. However, further improvements in its performance have been constrained by challenges in optimizing the structure and arrangement of dimples. In this study, we propose a novel approach based on hybridization enhancement, where the dimpled tube is combined with a twisted tape, introducing a new mechanism for heat transfer improvement. Numerical simulations demonstrate that this hybrid design can boost the average heat transfer coefficient by up to approximately 16 % compared to the conventional dimpled tube. Systematic analyses reveal that the circumferential flow induced by the twisted tape significantly enhances the utilization of dimples, thereby improving heat transfer performance, assuming the number and shape of dimples remain constant. The degree of enhancement is found to depend on the height and pitch of the twisted tape. To quantify these effects, we introduce the dimple utility indicator (DUI), defined as the number of dimples exposed to fluid flow per unit time, effectively measuring the \"dimple washing rate.\" Simulation results confirm that a higher DUI is the primary factor contributing to heat transfer enhancement. Furthermore, the DUI increases with the height of the tape and decreases as the tape pitch decreases.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105867"},"PeriodicalIF":6.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438256","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}

{"title":"Thermal analysis using Prandtl nanofluid in a non-uniform channel: Computational paradigm focusing on complex cilia waves","authors":"Maalee Almheidat ,&nbsp;Mohammad Alqudah ,&nbsp;Ali Imran ,&nbsp;F.M. Allehiany ,&nbsp;M.M. Alqarni ,&nbsp;M.S. Alqurashi ,&nbsp;Emad E. Mahmoud","doi":"10.1016/j.csite.2025.105872","DOIUrl":"10.1016/j.csite.2025.105872","url":null,"abstract":"<div><div>Applications of complex cilia waves may play a vital role in advancing medicine, robotics, fluid dynamics, and environmental technologies. By simulating the synchronized movements of cilia, researchers are developing efficient systems for fluid manipulation, propulsion, and drug delivery. Non-Newtonian nanofluids enhance thermal properties, enable precise flow control, and adapt effectively to complex systems. This work elaborates rheological and thermal aspects of MHD non-Newtonian nanofluids with complex metachronal wave. This investigation aims to enrich engineering design procedures by implementing second-order velocity slip and thermal slip conditions. A mathematical model is presented for cilia induce transport of a Prandtl fluid with nanofluid axioms through a non-uniform ciliated micro-channel by applying magnetic field, second-order velocity slip and thermal slip at the boundaries. Formulation for the physiological fluid transport is made and equations of motion are simplified with pertinent flow scenarios. The solution of the physical fluid transport is carried out with novel BVP5C technique in the MATLAB and computational manipulations are validated with Artificial Neural Network. It has been observed that the nanofluid transport is enhanced at the boundaries by making slip parameters strong, size of the trapped bolus is reduced with Prandtl fluid parameters suggested that this parameter may give driving force to nanofluid flow. Temperature of the nanofluid is significantly raised with the implementation of thermal slip and reduced with variable thermal conductivity. Concentration of the nanofluid is surged with variable thermal conductivity and is declined with Biot number. The pumping phenomenon is lifted with Prandtl fluid parameters and may be controlled with velocity slip, and Darcy parameters, also heat transfer coefficient is affected with Prandtl fluid parameters.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105872"},"PeriodicalIF":6.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429626","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}