Applied Thermal Engineering最新文献

{"title":"Numerical study on heat and ion transport characteristics enables optimal design of aqueous thermocells for low-grade heat recovery","authors":"Yanyu Shen ,&nbsp;Gao Qian ,&nbsp;Xiaoli Yu ,&nbsp;Zhi Li ,&nbsp;Yuqi Huang","doi":"10.1016/j.applthermaleng.2024.124970","DOIUrl":"10.1016/j.applthermaleng.2024.124970","url":null,"abstract":"<div><div>As a cutting-edge heat-to-electricity technology, thermogalvanic cells (thermocells) have great prospects in low-grade heat recovery due to its high Seebeck coefficient (<em>Se</em>), high scalability and low cost. Most of previous studies about aqueous thermocells have been focused on the overall performance by experimentally exploring advanced electrode and electrolyte materials, while very few simulation studies were reported before, leading to the unclear mechanisms of heat and ion transport inside the thermocell. In view of these challenges, this study aims to reveal the heat and ion transport characteristics of aqueous thermocells under various critical operating parameters, providing theoretical guidelines for further design and optimization of aqueous thermocells with fixed electrode and electrolyte materials. Firstly, a multi-physical model considering the diffusion, migration and convection was established and validated. Then, the effects of hot electrode temperature, electrode spacing and electrode orientation were evaluated on the thermocell performance from the aspects of distributions of multi-physical fields, overpotentials and overall performance. Finally, a prototype aqueous thermocell was proposed based on the understandings of restrictions associated with these operating parameters. Results indicated that each operating parameter can attribute to the variation of natural convection from the intensity and forms, and then affected the ion transport flux and overpotentials, and thus determined the power density of thermocells. These findings prompted the design and optimization of new aqueous thermocells, and the proposed prototype thermocell delivered the maximum power density of 0.43 W/m², which was 115 % higher than that of the basic rectangular thermocell.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 124970"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698349","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":"Experimental and numerical assessment on co-combustion of hydrogen with ammonia in passive pre-chamber engines","authors":"Yanfei Qiang ,&nbsp;Shihao Zhao ,&nbsp;Fangxu Su ,&nbsp;Fuzhi Wang ,&nbsp;Jinxin Yang ,&nbsp;Shuofeng Wang ,&nbsp;Changwei Ji","doi":"10.1016/j.applthermaleng.2024.124919","DOIUrl":"10.1016/j.applthermaleng.2024.124919","url":null,"abstract":"<div><div>This paper explores the combustion and emission characteristics of TJI ammonia/hydrogen (NH₃/H₂) dual-fuel engines through experiments and numerical simulations. The NH₃/H₂ engine operates at 1600 rpm with a manifold absolute pressure of 60 kPa. Two independent hydrogen supply systems enable hydrogen port injection (HPI) and hydrogen direct injection (HDI). The results indicate that HDI yields higher power output compared to HPI. The strong injection ignition ability of the pre-chamber (PC) realizes the stable combustion of the NH₃/H₂ engine under different ammonia volume share (AVS) conditions. With the increase of AVS, the mixture of HDI in PC is stratified and the jet velocity is significantly reduced. Power output under HDI conditions decreases with increasing AVS. At an AVS of 10 %, the brake mean effective pressure (BMEP) and brake thermal efficiency (BTE) reach maximum values of 3.67 bar and 30.25 %, respectively. The BMEP and BTE increase and then decrease with increasing AVS under HPI conditions. An AVS of 40 % achieves peak power and efficiency. The CA10-90 is always shorter than CA0-10 in the combustion process. At an AVS of 20 %, NO emissions peak and then decrease with increasing AVS, but higher AVS increases unburned NH₃ and N₂O. Experimental results show that spark timing (ST) has relatively low sensitivity to H₂-dominated TJI NH₃/H₂ combustion. With the increase of AVS to 60 %, the delayed ST will lead to a rapid decrease in power output and a sharp deterioration in combustion stability. When the ST is postponed from 12 °CA BTDC to 4 °CA ATDC, and AVS is 60 %, the COV_Pmax of the TJI engine increases rapidly from 1.9 % to 13.9 %.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124919"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705304","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":"Feasibility and parametric study of a groove-type thermoelectric generator under multiphysics field conditions","authors":"Ding Luo ,&nbsp;Zerui Liu ,&nbsp;Jin Cao ,&nbsp;Yuying Yan","doi":"10.1016/j.applthermaleng.2024.124972","DOIUrl":"10.1016/j.applthermaleng.2024.124972","url":null,"abstract":"<div><div>In this study, we propose a novel thermoelectric generator (TEG) configuration called the groove-type TEG, which introduces triangular brackets to increase the contact area between thermoelectric semiconductors and conductive strips. Through a thermal-electric-mechanical multiphysics numerical model, the performance of the groove-type TEG under various parameters is evaluated. Our findings reveal that the output power of the groove-type TEG can be effectively improved by increasing the length and height of the grooves, and the total height of the upper and lower grooves should be lower than the height of the thermoelectric semiconductor. Moreover, the groove height ratio and thermoelectric semiconductor height play crucial roles in determining the TEG’s performance and mechanical stability. Considering the allowable thermal stress, the optimal height ratio is 0.125 (or 0.875) when the semiconductor height is less than 1.2 mm (or greater than 1.3 mm). The groove-type TEG reaches the output power and conversion efficiency of 0.84 W and 6.9 %, respectively, at the temperature difference of 200 K and the semiconductor height of 1.3 mm, which are 24.8 % and 0.2 % higher than those of the traditional π-type TEG. This work provides a new approach to enhancing the performance of thermoelectric generators.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124972"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705299","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":"Effect of swirler geometry on the outlet temperature profile performance of a model gas turbine combustor","authors":"Chaowei Tang ,&nbsp;Qian Yao ,&nbsp;Wu Jin ,&nbsp;Jianzhong Li ,&nbsp;Yisheng Yan ,&nbsp;Li Yuan","doi":"10.1016/j.applthermaleng.2024.124946","DOIUrl":"10.1016/j.applthermaleng.2024.124946","url":null,"abstract":"<div><div>This study investigates the impact of swirl numbers, swirl direction combinations, and recirculation zone geometries on outlet temperature distribution and combustion efficiency through numerical simulations using the standard k-ε turbulence model. The research focuses on how variations in swirl numbers and directions affect the formation of high-temperature zones, recirculation patterns, and overall combustor performance. The simulations demonstrate that an increase in the swirl number of the third swirler results in a shift of the local high-temperature zone towards the dome, whereas higher swirl numbers of the first and second swirlers amplify the temperature peak. When the second and third swirlers rotate in the same direction, recirculation occurs at the outlet, moving the high-temperature zone closer to the exit. A decrease in the number of fuel supply nozzles leads to a higher outlet temperature distribution factor (OTDF), while an increase in the number of nozzles enhances temperature distribution. The central recirculation zone significantly influences the outlet temperature of the combustor, with an optimal cold-state length-to-height ratio (L/H)_n of approximately 1.2 and a reactive-state (L/H)_r, of 2 improving temperature distribution. As the ratio decreases from 1.771 to 1.289, the OTDF decreases from 0.41 to 0.24. Higher swirl numbers increase combustion efficiency, with Case3 achieving 99.86%. Insufficient fuel–air mixing under low swirl conditions leads to incomplete combustion, whereas higher swirl numbers promote better mixing and efficiency. These findings provide a foundation for further advancements in high-performance aeroengine combustor design.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 124946"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698445","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":"Waste-Derived carbon porous materials for enhanced performance in adsorption chillers: A Step toward a circular economy","authors":"Agata Mlonka-Mędrala ,&nbsp;Katarzyna Jagodzińska ,&nbsp;Tomasz Bujok ,&nbsp;Wojciech Kalawa ,&nbsp;Tong Han ,&nbsp;Karol Sztekler ,&nbsp;Wojciech Nowak ,&nbsp;Łukasz Mika","doi":"10.1016/j.applthermaleng.2024.124968","DOIUrl":"10.1016/j.applthermaleng.2024.124968","url":null,"abstract":"<div><div>In this study, a comprehensive examination of commercial activated carbons and novel porous carbon materials derived from waste was conducted to evaluate their potential as bed materials in adsorption chillers driven by waste heat. The research uniquely focuses on synthesizing and analyzing sorbents from two distinct waste sources: lignin and excavated waste, aiming to expand the sustainable application of waste-derived materials. A thorough characterisation of the sorption properties was performed using mercury intrusion porosimetry, low-temperature gas adsorption, and dynamic vapour sorption measurements with methanol. These techniques provided detailed insights into the microporous structure and surface areas of the materials, ranging from 500 to 2000 m2/g for the activated carbons. Notably, the lignin-derived magnetic biochar demonstrated an exceptionally well-developed surface area and superior sorption properties at operational conditions of 30 °C, reaching relative adsorption of 59.89 % at P/P_o of 100 %—up to 70 % higher than that of commercially available activated carbons. This material’s performance highlights its potential as a high-efficiency adsorbent in adsorption chillers, surpassing many commercially available options. However, the char obtained from excavated waste exhibited limitations due to high ash and heavy metal content (786 mg/kg Pb and 127 mg/kg Zn), suggesting challenges for its use in activated carbon synthesis. This study bridges a critical knowledge gap by exploring innovative pathways for utilizing waste-derived porous carbon materials in adsorption cooling, thus contributing to the development of sustainable, waste-based solutions for heat-driven cooling applications.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 124968"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698342","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":"Reductions in GHG and unburned ammonia of the pilot diesel-ignited ammonia engines by diesel injection strategies","authors":"Xinran Wang ,&nbsp;Tie Li ,&nbsp;Xinyi Zhou ,&nbsp;Shuai Huang ,&nbsp;Run Chen ,&nbsp;Ping Yi ,&nbsp;Yibin Lv ,&nbsp;Yu Wang ,&nbsp;Honghua Rao ,&nbsp;Yanzhao Liu ,&nbsp;Xiaodong Lv","doi":"10.1016/j.applthermaleng.2024.124967","DOIUrl":"10.1016/j.applthermaleng.2024.124967","url":null,"abstract":"<div><div>How to reduce the exhaust NH₃ and N₂O emissions is very crucial for bridging the gap between the high greenhouse gas (GHG) reduction potential and the engineering application of ammonia engines with high ammonia energetic ratios (AER). In this study, experiments were conducted to explore how the diesel injection pressures and the split injections affect the characteristics of combustion, emissions, and thermal efficiency for the AER of 80 % in a LPDF (i.e., low-pressure injection ammonia-diesel dual-fuel) engine. As for the split injections, both the early first injection during the compression stroke and the postponed second injection after the top dead center (TDC) were detailed investigated. With the injection pressure of the pilot diesel increasing from 60 to 150 MPa, about 28 % reductions in the unburned NH₃ and about 13 % reductions in the N₂O are achieved. With the optimized split injections before the TDC, about 11 % reductions in the unburned NH₃, 13 % reductions in N₂O, and 1.1 % enhancements of the indicated thermal efficiency can be simultaneously achieved. For the split injections with the second injection after TDC, the exhaust temperature can be to some degree increased but result in more NH₃ and N₂O, alongside a decline in thermal efficiency. Numerical simulations show that the diesel spray targeting and mixture reactivity stratification can explain the mechanism behind the improved performance of the optimized split injections, suggesting the potential for further improvement by the co-optimization of diesel injection strategy and combustion chamber geometry for the LPDF operations with high AERs.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 124967"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698346","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 on flow boiling heat transfer characteristics of R513A in the horizontal microfin tubes","authors":"Suhan Zhang ,&nbsp;Leren Tao ,&nbsp;Lihao Huang ,&nbsp;Cheng Jin","doi":"10.1016/j.applthermaleng.2024.124969","DOIUrl":"10.1016/j.applthermaleng.2024.124969","url":null,"abstract":"<div><div>To address the growing demand for high-efficiency heat exchangers in refrigeration, air conditioning, and heat pump systems, this study investigates the boiling heat transfer performance of R513A (an environmentally friendly azeotropic refrigerant) in horizontal microfin and smooth tubes with a 5.89 mm ID. Using 3D transient simulations, the tubes were analyzed under operating conditions of a mass flux of 50 kg/(m²·s) and a saturation temperature of 5 °C. The simulation results were validated against experimental data within a ±10 % error margin, confirming the reliability of model. At the constant mass flux, both the microfin and smooth tubes exhibited predominantly wavy-stratified flow, where surface tension dominated bubble flow. Gravity effects became more pronounced in slug, plug, and wavy-stratified flows. Structural parameters of microfin tubes, such as helical angle, fin height and number of fins, significantly affected flow boiling heat transfer. Increasing the helical angle had limited effect on enhancing boiling heat transfer performance. Microfin tube 4# (helical angle of 28°) exhibited an 11.27 % reduction in the boiling heat transfer coefficient compared to microfin tube 2#, due to the uneven distribution of liquid droplets in the vapor phase further reduced liquid film continuity and thickness. Microfin tube 5# (fin height of 0.30 mm) achieved an average mainstream velocity 1.36 times that of tube 2# (fin height of 0.17 mm), enhancing heat transfer. Conversely, microfin tube 6# with 54 fins showed local drying, negatively impacting its heat transfer efficiency.<!--> <!-->In summary, microfin tube 5# exhibited the optimal heat transfer characteristics.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 124969"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697438","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":"Principles of operational optimization of CSP plants based on carbon dioxide mixtures","authors":"Francesco Crespi,&nbsp;Pablo Rodríguez-deArriba,&nbsp;David Sánchez,&nbsp;Lourdes García-Rodríguez","doi":"10.1016/j.applthermaleng.2024.124871","DOIUrl":"10.1016/j.applthermaleng.2024.124871","url":null,"abstract":"<div><div>This research, developed in the framework of the SCARABEUS project, studies the off-design performance of transcritical power cycles running on C₂-S₂ mixtures in Concentrated Solar Power applications. The objective of this work is to identify optimum operational strategies that maximize net energy production when exposed to variable ambient temperature, with special focus on the operation of the Heat Rejection Unit (Air-Cooled Condenser).</div><div>Four different strategies are identified, depending on ambient temperature: variable or constant condensation pressure for ambient temperatures lower than the design value, and constant turbine inlet temperature or constant return temperature of the heat transfer fluid for ambient temperature higher than design value. The results show that a combination of variable and constant minimum cycle pressure stands as the most promising alternative for low ambient temperatures, enabling net system efficiencies higher than 41%. As a drawback, this strategy poses potential issues on the control of the compressor inlet, which must be further investigated in future works. On the other hand, constant turbine inlet temperature enables higher net performance than constant return temperature of the heat transfer fluid, even if at the expense of a reduction in energy storage capacity for the same inventory of molten salts and the creation of detrimental thermal transients. Finally, it is found that the Air-cooled condenser configuration with all fans equipped with Variable Frequency Driver stands as the best alternative to maximize the techno-economic performance of the system.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 124871"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698400","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":"Efficient jet-assisted single-phase immersion liquid cooling for high heat-flux servers","authors":"Chendong Liu,&nbsp;Yongping Huang,&nbsp;Chengbin Zhang","doi":"10.1016/j.applthermaleng.2024.124935","DOIUrl":"10.1016/j.applthermaleng.2024.124935","url":null,"abstract":"<div><div>With the trend toward integration and decarbonization in data centers, exploring clean and efficient cooling solutions has become increasingly urgent. In response, this study proposes an innovative single-phase immersion liquid cooling (SPILC) system with jet-assisted enhancement. By establishing a three-dimensional cooling model, the performance of conventional and jet-assisted SPILC systems is compared. Moreover, an in-depth study is conducted on the impacts of different jet designs and heatsink optimization on jet-assisted SPILC systems. The results show that the thermal management performance of jet-assisted SPILC systems has significantly improved compared to the conventional one, with the electronic component temperature and coolant temperature uniformity index of jet-assisted SPILC systems decreasing by 6.1 % and 73.1 %, respectively. For the jet-assisted SPILC system, the coolant temperature uniformity is better in the horizontal layout, but the flow resistance is increased compared to the vertical layout. Moreover, its cooling performance improves with the increased jet flow rate ratio, which achieves the best at a jet angle of 90 °. Balancing the trade-off between flow resistance and heat transfer, the thermal management performance of jet-assisted SPILC systems is maximized when the jet-impacted high heat-flux device’s heatsink has a pin fin size of 3 × 3 mm.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124935"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705303","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":"Optimisation of a converging-diverging nozzle for the wet-to-dry expansion of the siloxane MM","authors":"Pawel Ogrodniczak ,&nbsp;Abdulnaser Sayma ,&nbsp;Martin T. White","doi":"10.1016/j.applthermaleng.2024.124870","DOIUrl":"10.1016/j.applthermaleng.2024.124870","url":null,"abstract":"<div><div>Wet-to-dry expansion within the nozzle guide vane of an ORC turbine has been proposed as a means to improve the power output of ORC systems for waste-heat recovery (&lt;<!--> <!-->250 °<span><math><mi>C</mi></math></span>). However, given the rapid fluid acceleration in the stator, the phases can develop significant velocity and temperature disparity due to density difference and finite rate of interphase heat transfer. Since these factors can significantly affect the phase-change process, wet-to-dry nozzle design techniques must account for non-equilibrium effects. The first part of this paper aims to further verify a previously developed quasi-1D inviscid non-equilibrium nozzle design tool by comparing it to non-equilibrium CFD simulations, which, unlike the design model, account for lateral flow variations, viscous and turbulence effects, along with secondary momentum forces. Within the CFD model, the interphase mass, momentum, and energy exchange models have been updated using correlations better tailored to evaporating droplet flows and a corrected drag equation. Moreover, the definition of the vapour mass fraction has been modified, while a simplified droplet breakup model has been used to predict the droplet size. The results from the CFD simulations indicate that the outlet vapour mass fraction is approximately 10 to 15% lower than that predicted by the quasi-1D tool. However, the overall flow behaviour and phase-change pattern were in satisfactory agreement, justifying the use of the design tool for 1D optimisation. As such, the quasi-1D tool is coupled to a gradient-based optimiser to optimise the nozzle pressure profile and enhance evaporation of siloxane MM for expansions with an inlet pressure ranging from 450 to 650 kPa, and inlet vapour quality of 0.3. CFD simulations of the optimised geometries indicate an increase of 3.3 to 5.7% in the outlet vapour mass fraction, which was raised from 84.9, 87.7 and 90.5% to 88.2, 93.4 and 95.7% for 450, 550 and 650 kPa inlet pressures respectively. However, a more abrupt expansion in the optimised nozzles resulted in the development of a shock and led to deterioration in nozzle efficiency compared to the baseline nozzles. Finally, a CFD-based shape optimisation was conducted, which demonstrated that it may be difficult to further enhance the vapourisation rate. However, the optimised geometry did mitigate the effect of the oblique shock that appears in the diverging section of the nozzle, raising the expansion efficiency by around 3%.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 124870"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697266","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}