Applied Thermal Engineering最新文献

{"title":"Multi-objective adaptive energy management strategy for fuel cell hybrid electric vehicles considering fuel cell health state","authors":"","doi":"10.1016/j.applthermaleng.2024.124270","DOIUrl":"10.1016/j.applthermaleng.2024.124270","url":null,"abstract":"<div><p>This study proposes a multi-objective adaptive energy management strategy for fuel cell hybrid electric vehicles considering fuel cell health state. By integrating rule-based control with multi-objective optimization methods, the strategy aims to improve system efficiency, extend the lifespan of proton exchange membrane fuel cells (PEMFC), and reduce operating costs. Based on a comprehensive model of PEMFC output characteristics and lifetime degradation, this study introduces an optimized point line (OPL) strategy. This strategy dynamically adjusts operating constraints according to the state of health (SOH) of the PEMFC, ensuring optimal vehicle performance throughout its lifecycle. To optimize the OPL strategy parameters, a particle swarm optimization algorithm with compression factor was employed, enhancing the strategy’s optimization efficiency, adaptability, and robustness to better handle various real-world operating conditions. The strategy was evaluated under US06 and WLTC driving cycles and compared with traditional power following (PF) and point line (PL) strategies. Results show that compared to the PL strategy, the OPL strategy achieved a 36.4% and 34.2% reduction in operating costs under US06 and WLTC cycles, respectively. Moreover, PEMFC lifetime degradation decreased by 44.9% and 39.4% in these cycles. In high-power regions, the average operating efficiency of PEMFC improved by 2%. The strategy demonstrated good adaptability to different driving conditions, providing an effective solution for optimizing the performance and durability of fuel cell hybrid electric vehicles.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142099656","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":"Operation Scheme analysis of a multipurpose small modular reactor under cogeneration condition based on a once-through steam generator dynamic model","authors":"","doi":"10.1016/j.applthermaleng.2024.124264","DOIUrl":"10.1016/j.applthermaleng.2024.124264","url":null,"abstract":"<div><p>Highly flexible load requirements and cogeneration economy need to challenge the operation of a multipurpose small modular reactor cogeneration plant with once-through steam generators. Therefore, the present study develops a once-through steam generator dynamic model to analyze the multipurpose small modular reactor operation scheme under cogeneration conditions at different power levels. The once-through steam generator dynamic model is derived based on conversation equations using the moving boundary method. It is verified with RELAP5 results and open literature and the maximum relative error is 3.21 %. Three operation schemes are proposed for multipurpose small modular reactor cogeneration operation: Scheme 1 with constant steam pressure and average coolant temperature, Scheme 2 with constant steam temperature and pressure, and Scheme 3 with constant steam temperature and pure sliding steam pressure. Steady-state and dynamic characteristics with three operation schemes are simulated and investigated at three power levels: 100 %, 70 % and 30 %. The steady-state results show that Scheme 1 is more favorable for the primary loop, while Scheme 2 is beneficial to the secondary loop, and Scheme 3 can improve the thermal efficiency at low power level. The transient findings indicate that disturbances from the reactor side have a significant impact on the once-through steam generator and the minimum settling time is 3.3 s. Consequently, steam temperature control of once-through steam generator is achieved by regulating the control rods for Schemes 2 and 3, while steam pressure is suggested to be controlled by the feedwater valve for Scheme 1. For cogeneration conditions at 70 % power level, Scheme 2 can achieve the highest steam flow of turbine, the highest steam flow of steam extraction and the smallest steam specific volume, which are 87.88 kg·s⁻¹, 28.96 kg·s⁻¹, and 0.0503 m³·kg⁻¹, respectively. Scheme 2 is recommended for high power levels under cogeneration operation. In contrast, Scheme 1 is more suitable for the condensing unit operation for low power levels.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142121691","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 free-energy based multiple-distribution-function lattice Boltzmann method for multi-component and multi-phase flows","authors":"","doi":"10.1016/j.applthermaleng.2024.124241","DOIUrl":"10.1016/j.applthermaleng.2024.124241","url":null,"abstract":"<div><p>This study presents the development of a multiple-distribution-function lattice Boltzmann model (MDF-LBM) for the accurate simulation of multi-component and multi-phase flow. The model is based on the diffuse interface theory and free energy model, which enable the derivation of hydrodynamic equations for the system. These equations comprise a Cahn-Hilliard (CH) type mass balance equation, which accounts for cross diffusion terms for each species, and a momentum balance equation. By establishing a relationship between the total chemical potential and the general pressure, the momentum balance equation is reformulated in a potential form. This potential form, together with the CH type mass balance equation, is then utilized to construct the MDF-LBM as a coupled convection–diffusion system. Numerical simulations demonstrate that the proposed MDF-LBM accurately captures phase behavior and ensures mass conservation. Additionally, the calculated interface tension exhibits good agreement with experimental data obtained from laboratory studies.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142088944","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":"Comparison between pool boiling system of graphene quantum dots and nitrogen-doped graphene quantum dots suspended in binary base fluids","authors":"","doi":"10.1016/j.applthermaleng.2024.124259","DOIUrl":"10.1016/j.applthermaleng.2024.124259","url":null,"abstract":"<div><p>Using nanofluids instead of conventional heat transfer fluids as a passive method is a well-established and widely used technique by researchers to increase the rate and thermal performance of engineering equipment. In this study, the hydrothermal method with a bottom-up approach was used for the synthesis of graphene quantum dots and nitrogen-doped graphene quantum dots. Then, nanofluid samples were prepared in a two-step process, by adding nanoparticles to binary base fluids of deionized water and ethylene glycol in volume concentrations of (50:50) and (60:40), in four concentrations of 100, 200, 500, and 1000 ppm. In order to better understand the boiling heat transfer mechanism and measure its characteristics such as critical heat flux and heat transfer coefficient, an experimental system was designed and built. Nanofluids based on graphene quantum dots have unique features such as compatibility with the environment, economic efficiency, high stability and suitable heat transfer capability. For this reason, their selection in the pool boiling heat transfer process, in addition to saving energy, is introduced as one of the most effective options for improving CHF and HTC. The tests were performed under saturated conditions, atmospheric pressure, and on a vertical flat and polished copper thermal plate. Prepared nanofluids GQDs and N: GQDs based on DI-water maintained their apparent stability for two months. For GQDs nanofluids at an optimal concentration of 500 ppm with a volume ratio of (60:40) DI-water and EG, compared to DI-water, the greatest increase in CHF and HTC is 90.69, 85.011 % and for N: GQDs at a concentration of 500 with a volume ratio (50:50) DI-water and EG, 75.37 and 78.17 % compared to DI-water.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142150763","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 investigation of a small-scale reversible high-temperature heat pump − organic Rankine cycle system for industrial waste heat recovery","authors":"","doi":"10.1016/j.applthermaleng.2024.124237","DOIUrl":"10.1016/j.applthermaleng.2024.124237","url":null,"abstract":"<div><p>Innovative technologies are required to mitigate the challenges of climate change. A reversible high-temperature heat pump (HTHP) − organic Rankine cycle (ORC) system can be used for effective utilisation of industrial waste heat in the lower temperature band &lt;100 °C. The system can provide useful process heat for industrial processes by operating in HTHP mode or generating power in ORC mode. This paper presents the experimental investigation of the reversible system in both HTHP and ORC modes. A single scroll unit was selected for the compressor (HTHP) and expander (ORC) roles, keeping the system compact. A HCFO refrigerant, R1233zd(E), with a low GWP value, was chosen as the working fluid for both operating modes. When operated in HTHP mode, a maximum compressor overall isentropic efficiency of 73.4 % and a COP_mech of 4.8 (ΔT_lift,rside = 41 K, T_sf,ev,in = 60 °C) was obtained. In ORC mode, the maximum net power output was 512.4 W (T_sf,ev,in = 90 °C, r_p = 2.3), overall cycle efficiency was 3.01 %, and overall isentropic efficiency of the expander was 54.6 %. The technical limitations encountered, and solutions put in place during the experimental testing campaign are discussed in detail.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1359431124019057/pdfft?md5=08934f6a28a48452423b1d8197478d43&pid=1-s2.0-S1359431124019057-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142087731","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":"Effects of motive flow temperature on holding steam ejector Performance under Condenser temperature change by considering Entropy generation and Non-equilibrium condensation","authors":"","doi":"10.1016/j.applthermaleng.2024.124268","DOIUrl":"10.1016/j.applthermaleng.2024.124268","url":null,"abstract":"<div><p>The condenser plays a crucial role as one of the key components in a power plant, directly influencing its overall efficiency. Any alteration in the power plant’s efficiency has a substantial impact on both energy consumption and the environment. The holding steam ejector (HSE) is essential for condenser operation by creating a vacuum and effectively removing air. The primary objective of this study is to evaluation the motive flow temperature (MFT) by considering various parameters such as steam price, production entropy, air suction, and entrainment ratio (ER). The investigation focuses on different temperatures within the power plant condenser. The study examines the changes in MFT within the range of 350 ˚C to 400 ˚C, as well as the variation in condenser temperature (CDT) spanning from 47 ˚C to 67 ˚C. The results demonstrate that varying the MFT impacts the functional parameters of the HSE. As the MFT increases, there is an increasing trend in the ER. Simultaneously, there is a decreasing trend observed in the cost of steam production, production entropy, and air suction. When the MFT increased from 350 ˚C to 400 ˚C, the suction air mass flow rate for temperatures of 47 ˚C, 57 ˚C and 67 ˚C decreases by 2.22%, 2.09% and 1.99%, respectively. These results highlight the influence of temperature on various parameters, showcasing how adjustments in the MFT and CDTs can affect the flow characteristics and associated factors in the system.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142099735","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 study on the impact of convective heat transfer on lithium battery air cooling thermal model","authors":"","doi":"10.1016/j.applthermaleng.2024.124220","DOIUrl":"10.1016/j.applthermaleng.2024.124220","url":null,"abstract":"<div><p>To enhance the accuracy of lithium battery thermal models, this study investigates the impact of temperature-dependent convective heat transfer coefficients on the battery’s air cooling and heat dissipation model, based on the sweeping in-line robs bundle method proposed by Zukauskas. By calculating and fitting the relationship between the convective heat transfer coefficient and temperature at flow rates of 0.05 m/s, 0.15 m/s, 0.25 m/s, and 0.35 m/s, it was found that the relationship is complex. An electrochemical-thermal coupling model was established using the operational characteristics of lithium batteries, and a thermal runaway reaction kinetics model was created using isothermal thermal runaway experiments and least squares optimization. The temperature-dependent convective heat transfer coefficient was then integrated into both models. Numerical simulations revealed that during normal discharge, the maximum temperature difference in the battery when the convective heat transfer coefficient is a function of temperature is less than 1 % compared to when it is constant. However, in the high-temperature thermal runaway model, the impact of temperature-dependent convective heat transfer coefficients on the thermal runaway critical parameters is minimal at flow rates of 0.05 m/s and 0.15 m/s. When the flow rate increases to 0.25 m/s and 0.35 m/s, the impact on the trigger time of thermal runaway is 17.34 % and 18.07 %, respectively. Experimental validation and research results indicate that the temperature effect on the convective heat transfer coefficient should be considered in high-temperature thermal runaway and thermal management models to calculate the convective heat transfer more accurately within the battery pack, improving model accuracy and reducing the risks of thermal runaway.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142099441","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 of solar-driven trilateral-like organic Rankine cycle with radial-inflow turboexpander","authors":"","doi":"10.1016/j.applthermaleng.2024.124239","DOIUrl":"10.1016/j.applthermaleng.2024.124239","url":null,"abstract":"<div><p>Low-temperature solar collectors coupled with thermal energy storage can enable stable and carbon-free energy production. This work proposes a fully integrated organic Rankine cycle (ORC) with solar field and thermocline direct energy storage. The organic fluid remains liquid inside the solar field and the thermal energy storage, leading to a trilateral-like thermodynamic cycle. As opposed to other trilateral (flash) cycles, the proposed system distinguishes itself by including a turboexpander to deal with two-phase expansion, leading to higher conversion efficiency. In particular, with the same turbine efficiency, the proposed cycle outperforms alternative integrated ORC-solar field configurations by 1.5–3.8 percentage points in thermodynamic cycle efficiency for maximum temperatures between <span><math><mrow><mn>400</mn><mtext>–</mtext><mn>600</mn><mspace></mspace><mstyle><mi>K</mi></mstyle></mrow></math></span>. The equivalent electric energy density also increases by 30% to 60%. The problem of the two-phase turbine is tackled by relying on a recently proposed radial-inflow turbine concept. The centripetal stator leverages the retrograde shape of the saturation curve to achieve a complete liquid-to-vapor expansion. As a result, the rotor can handle dry organic vapors without experiencing mechanical damage or additional losses from two-phase interactions. Preliminary turbine designs, obtained through optimization of a validated meanline method, consistently yield isentropic total-to-static efficiencies exceeding 85%, confirming the potential of the proposed system.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142099574","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 study of an aluminum based three-dimensional thermosyphon heat sink with microscale enhancement structure","authors":"","doi":"10.1016/j.applthermaleng.2024.124273","DOIUrl":"10.1016/j.applthermaleng.2024.124273","url":null,"abstract":"<div><p>One of the most significant limitations to the advancement of electronics is the issue of heat dissipation. Currently, air cooling remains the most widely used method for heat dissipation due to the advantages of low cost and ease of maintenance. However, the traditional air-cooling method based on an all-solid heat sink is unable to keep pace with the rapid advancement in thermal power of electronics due to its limitation in area expansion by only solid fins. This study proposes an aluminum-based three-dimensional thermosyphon (3D-TS) coupling boiling-condensation heat transfer and forced air cooling as a means of overcoming the limitations of conventional air-cooling methods. Additionally, the incorporation of micro pin-fins enhances the boiling heat transfer and the overall performance of the three-dimensional thermosyphon. The performance of the three-dimensional thermosyphon is experimentally studied and analyzed under different volumetric flow rates using the environmentally friendly refrigerant R1233zd(E) as the working fluid. The results indicate that the total thermal resistance exhibits a biphasic response to heating power, with a decrease initially followed by an increase. This response is primarily attributed to the boiling mode on the substrate. Moreover, the micro pin-fins significantly enhance the boiling heat transfer on the substrate of the three-dimensional thermosyphon, enabling the three-dimensional thermosyphon to reach a minimum thermal resistance of 0.075 K/W and a maximum thermal dissipating power of 650 W with the temperature of the heating source below 85 °C. The three-dimensional thermosyphon proposed in this work is capable of meeting the cooling requirements of the majority of high-performance chips. This paper offers a valuable reference and guidance for the design and optimization of the phase-change devices.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142121701","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 spring-mass-damper model based on separated phase flow mode for pulsating heat pipe with adjustive-structured channels","authors":"","doi":"10.1016/j.applthermaleng.2024.124275","DOIUrl":"10.1016/j.applthermaleng.2024.124275","url":null,"abstract":"<div><p>Pulsating heat pipe (PHP) is a kind of efficient passive phase-change cooling device. The pulsating behaviors of the two-phase flow inside PHP significantly affect the heat transfer performance for PHP, the investigation of which will greatly contribute to the optimal design of PHP for electronic heat dissipation in small space. In the present work, the heat transfer performance of PHP is optimized via structure analysis and modeling calculation. A new “spring-mass-damper” model in terms of separated phase flow mode is established, where the frictional pressure loss of the real two-phase flow pattern − slug flow in PHP is considered. Besides, a prototype of PHP with adjustive-structured channel (ASCPHP) is proposed. The heat transfer performance of ASCPHP is evaluated with the newly established model. With theoretical computation method, the frequency of ASCPHP the superiority of ASPHP is also confirmed by comparison with other types of PHPs.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142129532","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}