Applied Thermal Engineering最新文献

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Heat extraction mechanisms of CO2-water mixed-phase flow in a single fracture of hot dry rock
IF 6.1 2区 工程技术
Applied Thermal Engineering Pub Date : 2024-11-26 DOI: 10.1016/j.applthermaleng.2024.125074
Jiansong Zhang , Yongsheng Liu , Jianxin Xia , Jianguo Lv
{"title":"Heat extraction mechanisms of CO2-water mixed-phase flow in a single fracture of hot dry rock","authors":"Jiansong Zhang ,&nbsp;Yongsheng Liu ,&nbsp;Jianxin Xia ,&nbsp;Jianguo Lv","doi":"10.1016/j.applthermaleng.2024.125074","DOIUrl":"10.1016/j.applthermaleng.2024.125074","url":null,"abstract":"<div><div>Deep geothermal energy, recognized for its cleanliness and lack of pollution, has often overlooked the heat extraction dynamics of CO<sub>2</sub>-water two-phase flow within fractures. This study investigates the influence of H<sub>2</sub>O mixing ratios on the output thermal power(OTP) in CO<sub>2</sub>-Enhanced Geothermal Systems, particularly in regions where CO<sub>2</sub> and water coexist. To explore this, a geometric model of a single fracture within dry hot rock (φ50 × 100 mm) was first developed using a 3D self-affine fractal function. Subsequently, a numerical model was constructed to account for the thermophysical property variations of the CO<sub>2</sub>-water mixture within a pressure range of 30 MPa and temperatures between 200 °C and 330 °C. Key findings include: (1) An increase in fracture width results in non-linear variations in the temperature gradient between the inlet and outlet. Notably, the mixture containing 30 % H<sub>2</sub>O and 70 % CO<sub>2</sub> exhibited the most significant reduction in temperature difference, with a maximum decrease of 0.9 °C. (2) Fracture width has a profound impact on heat extraction efficiency, with the 60 % H<sub>2</sub>O and 40 % CO<sub>2</sub> mixture showing the highest increase in output thermal power. At a fracture width of 2 mm, coupled with higher flow velocities, this mixture achieved an output thermal power of 149.69 W. These results underscore the critical influence of H<sub>2</sub>O mixing ratios on heat extraction power in CO<sub>2</sub>-water coexisting regions, offering valuable insights into heat production processes within actual geothermal reservoirs.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 125074"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743649","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}
引用次数: 0
Thermal performance of a solar-assisted slinky foundation heat exchanger coupled with a heat pump in a cold climate
IF 6.1 2区 工程技术
Applied Thermal Engineering Pub Date : 2024-11-26 DOI: 10.1016/j.applthermaleng.2024.124986
Shayan Davani , Amirhossein Darbandi , Jordan Gruenes , Alison Hoxie , Aggrey Mwesigye
{"title":"Thermal performance of a solar-assisted slinky foundation heat exchanger coupled with a heat pump in a cold climate","authors":"Shayan Davani ,&nbsp;Amirhossein Darbandi ,&nbsp;Jordan Gruenes ,&nbsp;Alison Hoxie ,&nbsp;Aggrey Mwesigye","doi":"10.1016/j.applthermaleng.2024.124986","DOIUrl":"10.1016/j.applthermaleng.2024.124986","url":null,"abstract":"<div><div>Using the excavation of a building’s foundation offers a cost-effective solution to alleviate the high installation costs hindering the widespread adoption of ground-source heat pump systems. However, limited land space in urban areas and higher heating loads in cold climates pose challenges. Issues like ground thermal imbalances and prolonged freezing around the heat exchanger can impair performance. To address these, a novel solar-assisted ground source heat pump with a slinky foundation ground heat exchanger and a solar-heated recovery heat exchanger loop embedded in the building’s foundation is proposed. A 3D transient finite element numerical model is developed to evaluate the performance of the proposed system. Realistic building energy loads obtained from a building energy simulation with time-varying ambient temperature and solar irradiation are coupled to the foundation heat exchanger to predict the long-term transient performance of the system. Results show that implementing a solar-assisted foundation heat exchanger system reduces soil freezing from 58.3 % to 32.4 % of the year, and heat pump shut-off occurrences caused by low entering fluid temperature drop from 38.9 % to 5.8 %. Additionally, incorporating an auxiliary heater eliminates heat pump shut-offs and reduces the soil freezing period to 6.3 %. Moreover, extending the heat exchangers beyond the footprint of the house mitigates the soil freezing problem completely and reduces the demand for auxiliary heating.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"261 ","pages":"Article 124986"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142758989","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}
引用次数: 0
Revolutionizing electric vehicle cooling: Optimal performance of R1234yf two-phase refrigerant cooling for EV battery thermal management system
IF 6.1 2区 工程技术
Applied Thermal Engineering Pub Date : 2024-11-26 DOI: 10.1016/j.applthermaleng.2024.125070
Palanisamy Dhamodharan , Mohammad Salman , Rajendran Prabakaran , Gyu Sang Choi , Sung Chul Kim
{"title":"Revolutionizing electric vehicle cooling: Optimal performance of R1234yf two-phase refrigerant cooling for EV battery thermal management system","authors":"Palanisamy Dhamodharan ,&nbsp;Mohammad Salman ,&nbsp;Rajendran Prabakaran ,&nbsp;Gyu Sang Choi ,&nbsp;Sung Chul Kim","doi":"10.1016/j.applthermaleng.2024.125070","DOIUrl":"10.1016/j.applthermaleng.2024.125070","url":null,"abstract":"<div><div>This study investigates the effectiveness of R1234yf-based two-phase refrigerant cooling (TRC) in a secondary heat exchanger (test evaporator) designed for battery thermal management systems (BTMS) in electric vehicles. A brazed plate heat exchanger with an offset strip fin configuration is employed to assess various performance metrics, including heat-transfer coefficient (HTC), frictional pressure drop (FPD), cooling performance index (CPI), and inner wall temperature (T<sub>iw</sub>). Experiments are conducted across saturation temperatures (T<sub>sat</sub>) ranging from 16 to 24 °C, mass flux values of 30 to 70 kg/m<sup>2</sup>s, and inlet vapor-quality levels from 0.1 to 0.8 for standard discharge rates (C-rates) of 1.25. Additional experiments at lower (30 kg/m<sup>2</sup>s) and higher mass flux (50 kg/m<sup>2</sup>s) are performed for discharge rates of 1–1.5C to identify optimal conditions. Results indicate that R1234yf exhibits superior cooling performance across all C-rates at 30 kg/m<sup>2</sup>s and 20 ℃, with HTC increasing by 28 % for 1C and 26 % for 1.5C. The FPD decreases by 30.5 %, 26.4 %, and 21.9 %, leading to increases in the cooling performance index of 44 %, 33 %, and 24 % for 1C, 1.25C, and 1.5C, respectively. Lower mass flux (30 kg/m<sup>2</sup>s) yields reduced T<sub>iw</sub> at T<sub>sat</sub> of 20 °C across all discharge rates, with minimal T<sub>iw</sub> variations observed within specific x<sub>m</sub> ranges (0.57–0.67). A novel correlation is developed integrating a proposed battery and heat-transfer model, validated against experimental results with a 25 % error margin, suggesting further exploration in TRC-based BTMS. Additionally, carbon footprint analysis demonstrates the environmental superiority of R1234yf refrigerant, exhibiting a substantial Total Equivalent Warming Impact reduction of up to 4–28 % compared to conventional R134a refrigerant, affirming its eco-friendly nature and potential for utilization in TRC for battery cooling in BTMS.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 125070"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743749","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}
引用次数: 0
Comparative analysis of transient thermal behaviour and efficiency in longitudinal metal porous fin with combined heat and mass transfer under dehumidification conditions
IF 6.1 2区 工程技术
Applied Thermal Engineering Pub Date : 2024-11-26 DOI: 10.1016/j.applthermaleng.2024.125069
P.L. Pavan Kumar , B.J. Gireesha , P. Venkatesh , M.L. Keerthi
{"title":"Comparative analysis of transient thermal behaviour and efficiency in longitudinal metal porous fin with combined heat and mass transfer under dehumidification conditions","authors":"P.L. Pavan Kumar ,&nbsp;B.J. Gireesha ,&nbsp;P. Venkatesh ,&nbsp;M.L. Keerthi","doi":"10.1016/j.applthermaleng.2024.125069","DOIUrl":"10.1016/j.applthermaleng.2024.125069","url":null,"abstract":"<div><div>This investigation explores the transient thermal characteristics of longitudinal porous fins made of Aluminium (Al) and Copper (Cu), exposed to a dynamic moist airstream under dehumidification conditions. Heat and mass transfer processes are initiated when the fin surface temperature falls below the dew point temperature of the surrounding air, driven by differences in temperature and humidity ratios. Heat transfer within the porous structure is modelled using temperature-dependent convective coefficients and Darcy’s flow model, with the governing nonlinear partial differential equation transformed into dimensionless form and solved using the Finite Difference Method (FDM) to analyse the fin thermal profile and efficiency over time. These results reveal that Cu fin due to their superior thermal conductivity exhibit higher temperature profile and efficiency compared to Al fin across all pertinent parameters. A key finding is the significant impact of Relative Humidity (RH) on the thermal behaviour of the fin: as RH increases by 400%, the temperature distribution from base to tip decreases by 138% in Al due to its higher specific heat capacity, which enables it to absorb more latent heat and 85% in Cu, where the superior thermal conductivity allows for faster heat dissipation. As Darcy number (Da) decreases by 99%, the temperature distribution along the fin from base to tip increases by 0.058% in Al due to its lower thermal conductivity and 0.041% in Cu, where its higher thermal conductivity enables more efficient heat dispersion. These insights are pivotal for advancing fin design and optimization, facilitating improved thermal management in industrial applications under transient and dehumidifying conditions.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"261 ","pages":"Article 125069"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142756625","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}
引用次数: 0
Thermal and flow analysis of a refrigerated truck for cold chains under various conditions in practical use
IF 6.1 2区 工程技术
Applied Thermal Engineering Pub Date : 2024-11-26 DOI: 10.1016/j.applthermaleng.2024.125063
Hyun Sung Hwang , Youngho Rhee , Dongchan Lee
{"title":"Thermal and flow analysis of a refrigerated truck for cold chains under various conditions in practical use","authors":"Hyun Sung Hwang ,&nbsp;Youngho Rhee ,&nbsp;Dongchan Lee","doi":"10.1016/j.applthermaleng.2024.125063","DOIUrl":"10.1016/j.applthermaleng.2024.125063","url":null,"abstract":"<div><div>Heat infiltration from frequent door opening of refrigerated trucks during delivery for cold chains has a significant impact on food quality and energy consumption. This study investigates the flow and heat transfer characteristics inside a 15 m<sup>3</sup> refrigerated truck. Detailed analysis was conducted during the transient state after opening the truck door under several different practical conditions. The numerical method was validated using experimental data and showed an acceptable agreement. Initially, the flow inside a refrigerated truck body with no load and the fan off was investigated after opening two doors. Subsequently, the effects of the number of doors opened, fan operation, and amount of cargo loading were analyzed. When the truck was empty and the fans were operating with all doors opened, the forced flow region was located at the top and the natural convection region was located below. The temperature and infiltration heat increased significantly after the outside air was drawn in by the fans. When the fans were turned off, natural convection was dominant, and a rapid increase in temperature occurred when the inflow of outside air increased. When only one door was closed, the circulation of cold air was maintained, suppressing air inflow and rapidly increasing the air temperature. The rate of temperature increase was approximately 23 % slower for the half-loaded case than for the no-load case. The results of this study can contribute to reducing energy consumption by optimizing the operating strategy and geometry that can minimize the heat loss after opening the doors.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 125063"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743652","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}
引用次数: 0
Thermo-electric characteristics analysis of thermionic energy conversion in space nuclear reactors
IF 6.1 2区 工程技术
Applied Thermal Engineering Pub Date : 2024-11-26 DOI: 10.1016/j.applthermaleng.2024.124997
Haocheng Zhao, Chenglong Wang, Suizheng Qiu, Wenxi Tian, Guanghui Su
{"title":"Thermo-electric characteristics analysis of thermionic energy conversion in space nuclear reactors","authors":"Haocheng Zhao,&nbsp;Chenglong Wang,&nbsp;Suizheng Qiu,&nbsp;Wenxi Tian,&nbsp;Guanghui Su","doi":"10.1016/j.applthermaleng.2024.124997","DOIUrl":"10.1016/j.applthermaleng.2024.124997","url":null,"abstract":"<div><div>Among static energy conversion technologies, thermionic energy converters have emerged as the preeminent choice for space nuclear reactor applications, distinguished by their high efficiency, compact architecture, and exceptional operational reliability. A comprehensive system analysis code, developed in C++, has been employed to integrate a thermionic electron emission model, an electric circuit model, and a thermionic conversion efficiency model. Through this code, thermionic characteristics for both single components and multiple components configured in series and parallel have been calculated, with validation indicating an error margin of less than 0.2 A/cm<sup>2</sup>. The performance characteristics of an individual thermionic fuel element have been rigorously evaluated, and comprehensive sensitivity analyses have been conducted on both emitter and collector temperatures. Under steady-state conditions, a maximum power output of 9.32 kW has been demonstrated by series-connected elements, while parallel-connected configurations have achieved 752 W. Notably, in scenarios involving the loss of a heat sink, it has been observed that maintaining the operating voltage of parallel-connected elements below a specific threshold during the incident results in enhanced power output, thereby facilitating core cooling. This study provides critical insights into the optimization of design and performance for thermionic energy conversion elements in space nuclear reactor applications.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"261 ","pages":"Article 124997"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142756553","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}
引用次数: 0
Development of a multi-physics numerical model for a multi-component thermoelectric generator with discontinuous porosity in the exhaust gas channel
IF 6.1 2区 工程技术
Applied Thermal Engineering Pub Date : 2024-11-26 DOI: 10.1016/j.applthermaleng.2024.125043
Jung Hwan Lee, Tae Young Kim
{"title":"Development of a multi-physics numerical model for a multi-component thermoelectric generator with discontinuous porosity in the exhaust gas channel","authors":"Jung Hwan Lee,&nbsp;Tae Young Kim","doi":"10.1016/j.applthermaleng.2024.125043","DOIUrl":"10.1016/j.applthermaleng.2024.125043","url":null,"abstract":"<div><div>A critical technical challenge in the energy harvesting performance of a thermoelectric generator (TEG) is the optimal utilization of the thermal energy from exhaust gas. In most TEG applications, the exhaust gas flowing through the exhaust channel exhibits high inertia forces, causing significant temperature maldistribution on the hot surfaces of thermoelectric modules (TEMs). To address this challenge, we developed a numerical model that incorporates the primary multi-physics phenomena associated with TEGs, designed with a porous flow conditioner and extended surfaces for practical use. A reliable three-zone method is employed to simulate thermoelectric energy conversion phenomena, including the resulting heat pumping and Joule heating effects in individual TEMs. The model accounts for the communication effect between electrically connected TEMs by integrating Kirchhoff’s voltage and current laws into the solving process. A selective porous media method is proposed for accurately analyzing the pressure jump induced by the flow conditioner and the porosity jump occurring at the interfaces between the flow conditioner and plate fins while ensuring model convergence reliability. The developed numerical model aligns with experimental results, showing a maximum error of 5 %. Comprehensive analyses of TEM-wise heat absorption rates and channel-wise flow distribution characteristics were conducted to identify the optimal position and porosity of the flow conditioner. The findings demonstrate that optimal use of the flow conditioner improves the net output power of the TEG by 31.5 % compared to the case without any flow conditioner.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 125043"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743764","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}
引用次数: 0
A DFT-based kinetic equation for Co3O4 decomposition reaction in high-temperature thermochemical energy storage
IF 6.1 2区 工程技术
Applied Thermal Engineering Pub Date : 2024-11-26 DOI: 10.1016/j.applthermaleng.2024.125064
Lei Liu, Kexin Li, Hanzi Liu, Zhiqiang Sun
{"title":"A DFT-based kinetic equation for Co3O4 decomposition reaction in high-temperature thermochemical energy storage","authors":"Lei Liu,&nbsp;Kexin Li,&nbsp;Hanzi Liu,&nbsp;Zhiqiang Sun","doi":"10.1016/j.applthermaleng.2024.125064","DOIUrl":"10.1016/j.applthermaleng.2024.125064","url":null,"abstract":"<div><div>Thermal energy storage supports stable grid integration of variable renewable energy sources by reducing power curtailment and generation costs. Thermochemical energy storage (TCES) offers high energy density and long-duration, long-distance storage advantages, making it a focus in large-scale applications such as concentrated solar power plants. Metal oxide systems like Co<sub>3</sub>O<sub>4</sub>/CoO are widely used due to their operational flexibility, yet limited understanding of their decomposition kinetics hinders optimization of TCES materials and reactor design. In this study, we developed a rate equation based on density functional theory and transition state theory to identify the reaction mechanisms and rate constants at the gas–solid interface, prior to predict Co<sub>3</sub>O<sub>4</sub> decomposition kinetics. A microkinetic model was then constructed to couple surface reactions with oxygen ion diffusion across the bulk, which was integrated into a reactor model accounting for mass transfer steps. The model’s accuracy was validated against the data from the micro-fluidized bed thermogravimetric analyzer experiments. For particles smaller than 150 μm, the formation step of adsorbed O<sub>2</sub> (energy barrier of 0.8 eV) controls the reaction rate, while gas diffusion dominates the reaction rate for particles larger than 500 μm. To conclude, the optimal conditions for maximizing charge–discharge kinetics in TCES applications were identified as: 850–900 °C, 0–10 vol% O<sub>2</sub>, and 150–500 μm. This model provides theoretical guidance for optimizing TCES materials and reactor design, reducing experimental costs while maintaining accuracy.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 125064"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743847","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}
引用次数: 0
Dual-Module humidity pump with hollow fiber membranes for isothermal dehumidification in industrial drying
IF 6.1 2区 工程技术
Applied Thermal Engineering Pub Date : 2024-11-26 DOI: 10.1016/j.applthermaleng.2024.125062
Jinwoo Oh , Andrew J. Fix , Md Ashiqur Rahman , Davide Ziviani , James E. Braun , David M. Warsinger
{"title":"Dual-Module humidity pump with hollow fiber membranes for isothermal dehumidification in industrial drying","authors":"Jinwoo Oh ,&nbsp;Andrew J. Fix ,&nbsp;Md Ashiqur Rahman ,&nbsp;Davide Ziviani ,&nbsp;James E. Braun ,&nbsp;David M. Warsinger","doi":"10.1016/j.applthermaleng.2024.125062","DOIUrl":"10.1016/j.applthermaleng.2024.125062","url":null,"abstract":"<div><div>Traditional dehumidification and drying processes are energy-intensive as they involve cooling the air below the dew point to condense and remove water vapor. Vacuum membrane dehumidification offers energy-saving opportunities, but its full potential remains undeveloped due to the presence of water vapor within the vacuum pump and excessively high pressure ratios. Recent studies proposed a dual-module humidity pump (DMHP) to address this, but the increased air permeation into the system requires strategies to prevent air pressure buildup and diffusion barrier formation. This study investigates a DMHP, specifically designed to address these issues by incorporating hollow fiber membranes for isothermal dehumidification in industrial heat pump dryers (HPDs). Membrane geometry and properties are coupled with a partial pressure-driven ε-NTU method, and a discretized model is used to identify water vapor transport under sub-ambient conditions. Thermodynamic models of the components are developed, and membrane-integrated HPDs are compared to a conventional HPD. The proposed system’s specific moisture extraction rate (<span><math><mrow><mi>SMER</mi></mrow></math></span>) exceeds conventional HPDs by 69%. Global sensitivity analysis reveals that <span><math><mrow><mi>SMER</mi></mrow></math></span> is 7.2 times more responsive to ambient conditions than dryer inlet conditions, with membrane geometry and properties’ interactions exerting greater influence than their individual effects. The optimum pressure ratio for the water vapor compressor, ranging from 1.2 to 3.8 and adjustable via synchronized control of rotational speeds with the vacuum pump, enhances <span><math><mrow><mi>SMER</mi></mrow></math></span> by up to 33.7% with a vapor balance ratio of 0.84–0.89. The results suggest that future work should investigate further optimization of membrane modules and variable built-in volume ratio compressors to unlock the full potential of DMHP technology.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"261 ","pages":"Article 125062"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759071","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}
引用次数: 0
Numerical study of ducted fuel injection strategy for soot emissions reduction in a heavy-duty diesel engine
IF 6.1 2区 工程技术
Applied Thermal Engineering Pub Date : 2024-11-26 DOI: 10.1016/j.applthermaleng.2024.125066
Yanzhao An , Yuhan Zhang , Tao Chen , Minshuo Shi , Yuzhang Wang , Zhanwang Su , Yiqiang Pei
{"title":"Numerical study of ducted fuel injection strategy for soot emissions reduction in a heavy-duty diesel engine","authors":"Yanzhao An ,&nbsp;Yuhan Zhang ,&nbsp;Tao Chen ,&nbsp;Minshuo Shi ,&nbsp;Yuzhang Wang ,&nbsp;Zhanwang Su ,&nbsp;Yiqiang Pei","doi":"10.1016/j.applthermaleng.2024.125066","DOIUrl":"10.1016/j.applthermaleng.2024.125066","url":null,"abstract":"<div><div>This study investigates the method of ducted fuel injection (DFI) technology to improve fuel–air mixing and reduce soot emissions in heavy-duty diesel engines, addressing critical challenges in sustainable combustion technology. While optical engine experiments have demonstrated DFI’s potential for emissions reduction, challenges arise when translating these results to actual diesel engines due to differences in design and operational conditions. Unlike previous optical engine experiments, this work evaluates DFI under real engine operating conditions through comprehensive numerical simulations. For the first time, the mechanisms of soot emission formation and control with DFI in a practical engine are elucidated. Results show that injection timing significantly affects engine performance, with the optimal timing for the original engine at −12° CA ATDC, achieving an indicated mean effective pressure (IMEP) of 16.55 bar and minimizing soot emissions (1.78 g/kWh). The engine with a directly installed duct (without optimization) improves early-stage combustion but extends later-stage combustion, reducing IMEP to 14.90 bar and increasing soot and CO emissions. By optimizing duct parameters—such as jet direction, number of ducts, and offset angle—we improve fuel–air distribution and in-cylinder airflow dynamics. Our findings indicate that this optimization not only slightly increases the IMEP of 16.56 bar but also significantly reduces soot emissions by 8.99 % and hydrocarbons (HC) emissions by 96.05 % compared to the original engine. These findings highlight the potential of DFI technology for effective emission control and sustainable engine performance, advancing its practical application in heavy-duty diesel engines.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"260 ","pages":"Article 125066"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743747","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}
引用次数: 0
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