Applied Thermal Engineering最新文献

{"title":"Entropy-based evaluation and optimization of double-wall cooling structures: Design and experimental validation","authors":"Ziqiang Gao ,&nbsp;Tian Qiu ,&nbsp;Yue Song ,&nbsp;Yu Zhou ,&nbsp;Shuiting Ding ,&nbsp;Peng Liu ,&nbsp;Zongchao Li ,&nbsp;Ronghui Cheng ,&nbsp;Qiyu Yuan","doi":"10.1016/j.applthermaleng.2025.126125","DOIUrl":"10.1016/j.applthermaleng.2025.126125","url":null,"abstract":"<div><div>The design of double-wall structures must minimize the impact on engine performance while simultaneously ensuring effective cooling. Current research on cooling efficiency, which considers parameters such as blowing ratio, as well as studies on aerodynamic flow losses, do not adequately meet the design requirements for double-wall structures in engine environments. This paper presents an entropy-based cooling effectiveness (<em>ECE</em>) metric that integrates the cooling performance of double-wall structures with the associated system losses in the engine. This metric serves as an effective tool for comparing the design levels of various cooling structures under engine operating conditions. Simulation results indicate that external cooling structures with a small blowing ratio and internal cooling structures characterized by weak impingement and a high heat transfer area are pivotal in enhancing the low-entropy generation design of double-wall structures. A novel double-wall structure is proposed, which features V-shaped fins and small-blowing-ratio film-cooling holes (VF-SF). Experimental tests were conducted in a high-temperature wind tunnel, comparing the conventional 121 structure with the newly proposed VF-SF structure. The research findings revealed significant improvements in both overall cooling efficiency (<em>ϕ</em>) and <em>ECE</em> with the VF-SF design. Under comparable engine conditions, specifically with a bleed air ratio of 3.8 %, the VF-SF structure exhibited a 76 % increase in <em>ϕ</em> and an 84 % enhancement in <em>ECE</em>, marking a substantial advancement in low entropy generation design. These results offer critical insights for optimizing the design of double-wall structures within engine system environments and highlight the considerable potential for enhanced thermal management in aircraft engines.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"269 ","pages":"Article 126125"},"PeriodicalIF":6.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579903","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}

{"title":"Numerical simulation of single droplet growing and moving in a heat transfer environment with small size","authors":"Yi-Fan Li ,&nbsp;Liang-Bi Wang ,&nbsp;An-Ning Guo ,&nbsp;Jing-Long Zhang ,&nbsp;Zhi-Min Lin","doi":"10.1016/j.applthermaleng.2025.126060","DOIUrl":"10.1016/j.applthermaleng.2025.126060","url":null,"abstract":"<div><div>When the moist air is cooled to supersaturation state, the water vapor in the moist air will condense into droplets on cooling surface, which will have an effect on the heat transfer ability of cooling surface and the flow resistance of fluid flow passing the cooling, so it is especially important to study the growing and moving of droplets on the cooling surface. This paper developed a numerical model to account the droplet growing and moving, then, the growing and moving characteristics of an individual droplet are studied under some working conditions. Under some studied conditions the maximum mass of the droplet is 2.31 × 10^-5 mg; the average mass growing rate is 0.00909 mg/s; the average moving velocity is 0.176 m/s. The large receding contact angle and low inlet air velocity are both more favorable for the droplet growing and moving. The high inlet air relative humidity is more favorable for the droplet moving and growing.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"269 ","pages":"Article 126060"},"PeriodicalIF":6.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580034","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}

{"title":"Numerical investigation of supersonic gas-particle lance with shrouded oxygen jets for industrial furnaces","authors":"Qijia Yang,&nbsp;Shiliang Yang,&nbsp;Wengui Peng,&nbsp;Hua Wang","doi":"10.1016/j.applthermaleng.2025.126154","DOIUrl":"10.1016/j.applthermaleng.2025.126154","url":null,"abstract":"<div><div>Supersonic gas-particle two-phase flow has been pivotal in fields such as metallurgy, materials processing, and environmental engineering, where they enhance processes like steelmaking, cold spraying, and fluidized bed operations. This study numerically analyzes a supersonic gas-particle lance with a shrouding jet used in industrial furnaces, within an Eulerian-Lagrangian framework. After model validation, this study elucidates the mechanisms of gas jet and particle distribution characteristics of supersonic shrouding gas-particle flows under varying shrouding jet flow rates and temperatures. The findings suggest that higher flow rates and elevated temperatures of shrouding jet significantly extend the length of the supersonic region and enhance jet spraying efficiency. The axial velocity of injected particles positively correlates with shrouding parameters. At the free domain outlet, compared to a shrouding flow rate of 0.4 kg/s, particle speed increases by factors of 1.30, 1.52, and 1.75 at flow rates of 0.8 kg/s, 1.2 kg/s, and 1.6 kg/s, respectively. Furthermore, at shrouding temperatures of 500 K, 700 K, and 900 K, particle speed is 1.17, 1.34, and 1.48 times higher than that at 300 K. Increasing the shrouding jet flow rate enhances particle aggregation, steepening the slope of the radial particle cumulative frequency distribution, while temperature increases promote a more uniform particle distribution. Additionally, increasing flow rates enlarges the particle Reynolds number, intensifying gas–solid interactions, and enhances heat transfer between phases. The radial distribution of particles can be precisely controlled by adjusting the shrouding flow rate. This study bridges the knowledge gap by providing a comprehensive analysis of shrouding effects on gas–solid interactions, offering theoretical insights and practical guidance for optimizing lance design and improving energy efficiency in industrial furnace applications.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"269 ","pages":"Article 126154"},"PeriodicalIF":6.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580092","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}

{"title":"Analysis of a polymer-based textile-embroidered thermoelectric generator for harvesting electrical power from the human body","authors":"Salman Soltanian,&nbsp;Shohel Mahmud,&nbsp;Animesh Dutta","doi":"10.1016/j.applthermaleng.2025.126156","DOIUrl":"10.1016/j.applthermaleng.2025.126156","url":null,"abstract":"<div><div>Warm and lightweight clothing is indispensable in cold climates, and textile thermoelectric generators embroidered into fabrics provide a practical solution for harnessing body heat to generate electricity. This study performed analytical and numerical analyses for a textile thermoelectric generator with p-type legs composed of polymer:polyelectrolyte-coated threads and n-type legs made of silver-plated threads sewn on a thick wool fabric. The one-dimensional thermoelectric equations, derived from energy balance on small thermoelectric elements, were analytically solved for a constant Seebeck coefficient under three boundary conditions: (a) fixed temperatures at both sides, (b) fixed temperature at the hot side with convection at the cold side, and (c) convection at both sides. These conditions effectively simulate the thermal contact resistance encountered in wearable thermoelectric generators. Subsequently, a semi-analytical approach was applied to the one-dimensional thermoelectric equation for a p-type leg with linearly temperature-dependent Seebeck coefficient and thermal conductivity under ideal thermal contact with the heat sources. The analysis yielded the temperature and electric potential distributions along the textile thermoelectric legs, as well as the maximum achievable power, peak power current, and optimal load resistance. A higher temperature gradient significantly enhanced maximum power output and associated electric current. As the convective heat transfer coefficient increased, the maximum power and corresponding electric current initially rose sharply before stabilizing at higher values, influenced by the temperature gradient. With convective heat transfer on both sides and a temperature gradient of 50 K, a maximum power of 46.65 nW per thermocouple unit was achieved at a textile thickness of 15.9 mm. Interestingly, the analytical analysis revealed that the optimal load resistance for maximum power generation was unaffected by the boundary conditions and was consistently equal to the thermoelectric generator’s internal resistance. The thermoelectric generator-embroidered fabric reached a steady state power generation after 17 min, with the open-circuit voltage increasing linearly as more thermoelectric pairs were added. This study presents a comprehensive mathematical framework for analyzing and optimizing thermoelectric generator designs for industrial applications.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"269 ","pages":"Article 126156"},"PeriodicalIF":6.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609617","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}

{"title":"Direct-to-chip immersion liquid cooling for high-power vertical-cavity surface-emitting laser (VCSEL)","authors":"Jionghao Wang ,&nbsp;Chongxian Yuan ,&nbsp;Yang Li ,&nbsp;Chuanchuan Li ,&nbsp;Yongli Wang ,&nbsp;Xin Wei","doi":"10.1016/j.applthermaleng.2025.126137","DOIUrl":"10.1016/j.applthermaleng.2025.126137","url":null,"abstract":"<div><div>The performance of high-power laser diodes (HPLDs) is critically dependent on effective thermal management strategies. This study presents an innovative thermal management technique for high-power Vertical-Cavity Surface-Emitting Laser (VCSEL) through direct-to-chip liquid cooling. The effectiveness of this approach was assessed through comprehensive theoretical simulations and experimental analysis. Results indicate that the immersion cooling system facilitates multidimensional heat dissipation, effectively extracting heat from VCSEL arrays and enhancing both efficiency and power stability. In comparison to traditional TEC cooling, immersion cooling lowers junction thermal resistance and increases the optical output power of VCSELs. This comparative advantage makes immersion cooling a more effective solution for HPLD thermal management.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"269 ","pages":"Article 126137"},"PeriodicalIF":6.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580036","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}

{"title":"A novel ultra-compact combustor with low flow resistance for the aero-engine","authors":"Dongliang Ren ,&nbsp;Weijun Fan ,&nbsp;Rongchun Zhang","doi":"10.1016/j.applthermaleng.2025.126139","DOIUrl":"10.1016/j.applthermaleng.2025.126139","url":null,"abstract":"<div><div>The use of an ultra-compact combustor has the potential to enhance the lightweight and durable characteristics of aero-engines. To reduce flow loss and achieve stable combustion in a compact space, a novel ultra-compact combustor based on trapped-vortex combustion technology was proposed in this study. The impact of the secondary flow ratio (λ) on the flow and combustion characteristics was investigated through a combination of numerical and experimental analysis methods. The nonreacting flow results demonstrated that with increasing λ value, the large-scale streamwise vortex within the cavity gradually decreases and subsequently results in a more stable spanwise vortex. However, increasing the λ value results in higher flow loss, and the total pressure recovery coefficient ranges from 96.6 % to 98.8 % at Mach 0.28. The airflow residence time is less than 1.5 ms, which significantly influences the ignition performance. The combustion results showed that an increase in λ increases the combustion efficiency and reduces the outlet temperature distribution factor. In addition, there is a correlation between the CRT and the ignition fuel–air ratio (FAR). The higher the CRT is, the longer the fuel–air residence time and the lower the FAR. The ignition performance is highest at λ = 21.9 %, and the ignition FAR values range from 0.009 to 0.015. The strong-combustion zone is concentrated at the junction of the front wall of the cavity and the guide vane during stable combustion, and the combustion intensity is highest for λ = 20.1 % at the same equivalence ratio.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"269 ","pages":"Article 126139"},"PeriodicalIF":6.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562165","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}

{"title":"Research on the thermal response characteristics of turbine blades considering engine operating conditions","authors":"Chengliang Lv,&nbsp;Longfei Wang,&nbsp;Yiming Liu,&nbsp;Junkui Mao,&nbsp;Tianyi Wang,&nbsp;Xinzi Liu,&nbsp;Dewei Zhang","doi":"10.1016/j.applthermaleng.2025.126140","DOIUrl":"10.1016/j.applthermaleng.2025.126140","url":null,"abstract":"<div><div>The sudden change of turbine inlet temperature rise in the operating conditions of an aero-engine seriously affects the blade heat load and even the overall life of the engine. In order to clarify the influence of the temperature rise process of the mainstream combustion air on the turbine blade temperature response, the study focuses on the high-pressure turbine stator NASA GEE3, utilizing a combination of numerical calculations and experimental measurements to investigate the impact of Reynolds number, temperature rise rate, and temperature rise curve on turbine blade thermal response characteristics. Compared to the blade height direction, the temperature thermal response difference is more pronounced along the chord direction. Temperature response rate follows the order of trailing edge, leading edge, and middle edge, from fastest to slowest. Increasing Reynolds number enhances the mass flow rate of the gas that contacts the blade, improving the heat transfer capability and accelerating the rate of temperature change on the blade surface in response to changes in inlet temperature. The temperature response is more pronounced at higher Reynolds number. Lower temperature rise rates improve the heat transfer time between the gas and blade, enhancing the blade surface temperature’s response rate. The inlet’s convex temperature rise curve leads to the fastest thermal response at the trailing edge, with a temperature lag of only 3.23%.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"269 ","pages":"Article 126140"},"PeriodicalIF":6.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580027","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}

{"title":"Thermal insulation design for superheated steam pipeline transport: Balancing technical and economic factors for optimal performance","authors":"Chao Lou ,&nbsp;Chong Zhai ,&nbsp;Lun Li ,&nbsp;Yuhe Shang ,&nbsp;Xiaohui Li ,&nbsp;Dong Li","doi":"10.1016/j.applthermaleng.2025.126134","DOIUrl":"10.1016/j.applthermaleng.2025.126134","url":null,"abstract":"<div><div>Proper pipe insulation design ensures efficient and reliable heat transfer to end-users in the heating network. Optimizing pipeline insulation design requires balancing technical and economic factors to enhance energy efficiency and promote environmental sustainability. This study evaluates optimal insulation thickness using a steam pipeline transport model and life-cycle cost analysis, examining variables, including pressure, superheat degree, pipe diameter, and composite insulation schemes within a supersaturated steam network. A condensate term was incorporated to account for phase change effects in vapor transport, improving the accuracy of the model and reducing the enthalpy discrepancy to only 0.101 %. The results indicate that an insulation structure featuring a 74 mm aerogel blanket (AB) as the inner layer and 500 mm glass wool (GW) as the outer layer achieves optimal performance under a superheat of 10 °C, pressure of 0.8 MPa, and pipe diameter of DN600. The life-cycle cost optimization demonstrated a payback period of less than three years for the optimal insulation scheme. Furthermore, the optimal insulation thickness increases linearly with superheat and pressure, with economic parameters, such as energy efficiency and total cost, exhibiting a nonlinear decline at higher pressures.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"269 ","pages":"Article 126134"},"PeriodicalIF":6.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580090","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}

{"title":"Assessing the effect of size variation in graphite and alginate matrices for thermochemical heat storage","authors":"Jack Reynolds,&nbsp;Nigel Koungampillil,&nbsp;Jonathon Elvins,&nbsp;Eifion Jewell,&nbsp;Justin Searle,&nbsp;Nicola C Mumford,&nbsp;Cameron Pleydell-Pearce,&nbsp;Richard E Johnston","doi":"10.1016/j.applthermaleng.2025.126138","DOIUrl":"10.1016/j.applthermaleng.2025.126138","url":null,"abstract":"<div><div>The charging and discharging performance of thermochemical heat storage (TCHS) materials within practical applications will be influenced by key material and reactor properties such as thermal conductivity, ease of airflow through the material bulk and moisture exchange kinetics. This study examines the impact of varying the bead size of Alginate-Graphite-CaCl₂ composites on the thermal and kinetic performance under static and dynamic conditions. Successful synthesis was achieved, with variations in composite composition ascribed to differential shrinkage factors during freezing. XCT studies highlighted improved packing with decreasing bead diameter although this significantly increases the differential pressure across the bed. Smaller diameters result in increased water sorption, which corresponds with higher peak temperatures and sustained temperature elevation during discharging analysis. Charging materials at temperatures between 90–150 °C has minimal effect on the ultimate charge profile. However, materials with large diameters display an improved charging efficiency advantage up to a charging level of 50 % but ultimately the smallest composites exhibit a slight efficiency improvement at 95 % charge.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"269 ","pages":"Article 126138"},"PeriodicalIF":6.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580191","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":"Gas-particle flow and combustion performance of prototype and enhanced burners under minimum stable load: From laboratory to industrial scale","authors":"Xiuyi Wu ,&nbsp;Gaoke Xia ,&nbsp;Huacai Liu ,&nbsp;Zhengqi Li ,&nbsp;Chunchao Huang ,&nbsp;Xiuli Yin ,&nbsp;Xiao Guo ,&nbsp;Jun Cheng ,&nbsp;Xuemin Guo","doi":"10.1016/j.applthermaleng.2025.126141","DOIUrl":"10.1016/j.applthermaleng.2025.126141","url":null,"abstract":"<div><div>The operational frequency of coal-fired units undertaking deep peak-shaving loads has significantly increased, with stable combustion under ultra-low loads emerging as a critical challenge for grid security. This study conducts the first systematic comparison of a prototype low-NOx swirl burner (L-D) with two enhanced variants (L-A, L-C) under 180MWe conditions (27% rated load). A hybrid approach, combining 1:4.5 lab-scale cold-flow experiments and full-scale industrial tests on a 660 MWe wall-fired boiler operating at minimum stable load without auxiliary fuel, was employed. Key findings are demonstrated: the recirculation zone of L-C was the longest (0.63 nozzle diameters), with a peak reflux ratio exceeding 60 % at axial positions of x/d = 0.3–0.4. Stronger axial velocity decay and radial diffusion were observed in L-A than in L-D, whereas L-C maintained a more concentrated particle distribution. The calculated swirl numbers were 0.584 for L-C, 0.495 for L-A, and 0.440 for L-D. Ignition distances were measured as 1.36 m for L-C, 1.47 m for L-A, and 2.39 m for L-D. NO_x emissions from L-C exceeded 1600 mg·m^-3 (6% O₂) at 1.2 m from the burner outlet, while incomplete combustion in L-A led to CO concentrations reaching 11,196 ppm in near-wall regions. This integrated lab-industrial investigation bridges the experimental gap for sub-30 % load operations and establishes design-performance correlations for deep peak-shaving retrofits.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"269 ","pages":"Article 126141"},"PeriodicalIF":6.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580028","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}