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Design and application of electric oil pump in automatic transmission for efficiency improvement and start–stop function 被引量:1
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作者 刘艳芳 董鹏 +1 位作者 刘洋 徐向阳 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第3期570-580,共11页
For the purpose of improving efficiency and realizing start–stop function, an electric oil pump(EOP) is integrated into an 8-speed automatic transmission(AT). A mathematical model is built to calculate the transmissi... For the purpose of improving efficiency and realizing start–stop function, an electric oil pump(EOP) is integrated into an 8-speed automatic transmission(AT). A mathematical model is built to calculate the transmission power loss and the hydraulic system leakage. Based on this model, a flow-based control strategy is developed for EOP to satisfy the system flow requirement. This control strategy is verified through the forward driving simulation. The results indicate that there is a best combination for the size of mechanical oil pump(MOP) and EOP in terms of minimum energy consumption. In order to get a quick and smooth starting process, control strategies of the EOP and the on-coming clutch are proposed. The test environment on a prototype vehicle is built to verify the feasibility of the integrated EOP and its control strategies. The results show that the selected EOP can satisfy the flow requirement and a quick and smooth starting performance is achieved in the start–stop function. This research has a high value for the forward design of EOP in automatic transmissions with respect to efficiency improvement and start–stop function. 展开更多
关键词 automatic transmission electric oil pump mechanical oil pump start-stop function efficiency improvement forwarddriving simulation control strategy
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A NUMERICAL SIMULATION OF 3-D INNER FLOW IN UP-STREAM PUMPING MECHANICAL SEAL 被引量:9
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作者 ZHANG Jin-feng YUAN Shou-qi +1 位作者 FU Yong-hong FANG Yu-jian 《Journal of Hydrodynamics》 SCIE EI CSCD 2006年第5期572-577,共6页
Numerical simulation of 3-D inner flow between Up-stream Pumping Mechanical Face Seals (UPMFS) faces was initially done by CFD software, which made the flow visualization come true. Simulation results directly disco... Numerical simulation of 3-D inner flow between Up-stream Pumping Mechanical Face Seals (UPMFS) faces was initially done by CFD software, which made the flow visualization come true. Simulation results directly discover the action of hydrodynamic lubrication, and by comparison with that of Conventional Mechanic Face Seals (CMFS), the advantage over bigger bearing capability, less friction and much less leakage are explained clearly. Otherwise there are also some different ideas and results from precedent analysis and computational research results: dynamic and static pressure profiles can be obtained respectively instead of the analytic total pressure distribution only, pressure distribution is nonlinear, while always be solved as linear, lower pressure is observed at the area of inner diameter caused by the grooves, but its possible cavitations effects to the performance of UPMFS still need further study. 展开更多
关键词 Up-stream (UPMFS) Conventional hydrodynamic lubrication simulation pumping mechanical Face Seals mechanic Face Seals (CMFS) visualization of flow numerical simulation
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Experimental study on dynamic behavior of mechanically pumped two-phase loop with a novel accumulator in simulated space environment 被引量:1
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作者 Qingliang MENG Tao ZHANG +3 位作者 Feng YU Yu ZHAO Zhenming ZHAO Zhenhua ZHOU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2022年第12期102-116,共15页
Mechanically pumped two-phase loop(MPTL)which is a prominent two-phase heat transfer technology presents a promising prospect in thermal control for space payload.However,transient behavior of MPTL caused by phase-cha... Mechanically pumped two-phase loop(MPTL)which is a prominent two-phase heat transfer technology presents a promising prospect in thermal control for space payload.However,transient behavior of MPTL caused by phase-change and heat sources load-on/off in simulated space environment is rarely reported.In the present study,one MPTL setup was designed and constructed,and experimentally studied.Particularly,a novel two-phase thermally-controlled accumulator integrated with passive cooling measure and three capillary structures was designed as the temperature-control device.Dynamic behavior of the start-up,temperature control,and temperature adjustment were monitored;meanwhile,thermodynamic behavior within the proposed accumulator,the operating behavior as well as the heat and mass transfer behavior between the main loop and the accumulator were revealed.The results show that the fluid management function of the capillary structures for the novel accumulator is verified.The working point of the MPTL system can be adjusted by changing the temperature control point of the accumulator and it is little influenced by external heat flux and heat sources on/off.Pressure-drop oscillations which are manifested as fluctuations of temperature and pressure can be observed after phase changing due to the compressible volume within the accumulator and the negative-slope portion of the internal pressure. 展开更多
关键词 Heat and mass transfer mechanically pumped twophase loop(MPTL) Pressure drop fluctuation Thermal control Two-phase flow
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Generation of Interstellar Class Ⅱ 7_2-8_1A^+ and 7_2-8_1A^-Methanol Masers
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作者 Han-Ping Liu Jin Sun 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第6期803-808,共6页
New methanol maser lines at 72 → 63A^-(86.6 GHz) and 72 → 63A^+(86.9 GHz) together with two candidate methanol maser lines at 72 → 81A-(80.99GHz) and 72→81A^+(111.29GHz) have been detected in W3(OH). W... New methanol maser lines at 72 → 63A^-(86.6 GHz) and 72 → 63A^+(86.9 GHz) together with two candidate methanol maser lines at 72 → 81A-(80.99GHz) and 72→81A^+(111.29GHz) have been detected in W3(OH). We use a pumping mechanism, i.e., methanol masers without population inversion, to explain the formation of weak methanol masers of 72 → 81A^+ and 72→ 81A^-. We explain well why the line-shape of the transition 72 → 81A^+ is not typical. A similar argument can be applied to the A-type level system 72A^-, 63A^- and 81A^-, as well as to the 72 → 81A^- 80.99 GHz masers. 展开更多
关键词 pumping mechanism -- Class II methanol sources -- maser without inversion-- coherent microwave field
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Seasonal Wind Characteristics and Prospects of Wind Energy Conversion Systems for Water Production in the Far North Region of Cameroon
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作者 Dieudonné Kaoga Kidmo Bachirou Bogno +1 位作者 Kodji Deli Deli Goron 《Smart Grid and Renewable Energy》 2020年第9期127-164,共38页
<span style="font-family:Verdana;">This study aimed at investigating the characteristics of the wind power resource in the Far North Region of Cameroon (FNR), based on modelling of daily long-term sate... <span style="font-family:Verdana;">This study aimed at investigating the characteristics of the wind power resource in the Far North Region of Cameroon (FNR), based on modelling of daily long-term satellite-derived data (2005-2020) and </span><i><span style="font-family:Verdana;">in-situ</span></i><span style="font-family:Verdana;"> wind measurements data (1987-2020). Five</span><span><span><span><span><span style="font-family:;" "=""> </span></span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">different reliable statistical indicators assessed the accuracy level for the goodness-of-fit tests of satellite-derived data. The two-parameter Weibull distribution function using the energy factor method described the statistical distribution of wind speed</span></span></span></span></span><span><span><span><span><span style="font-family:;" "=""> </span></span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">and investigated the characteristics of the wind power resource. Six 10-kW pitch-controlled wind turbines (WT) evaluated the power output, energy and water produced. A 50 m pumping head was considered to estimate seasonal variations of volumetric flow rates and costs of water produced. The results revealed that the wind resource in FNR is suitable only</span></span></span></span></span><span><span><span><span><span style="font-family:;" "=""> </span></span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">for wind pumping applications. Based on the hydraulic requirements for wind pumps, mechanical wind pumping system can be the most cost-effective option of wind pumping technologies in FNR. However, based on the estimated capacity factors of selected WT, wind electric pumping system can be acceptable for only four out of twenty-one sites in FNR.</span></span></span></span></span> 展开更多
关键词 In Situ Wind Measurements mechanical Wind pumping Wind Electrical pumping Satellite-Based Wind Resource Wind Energy Far North Cameroon
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Review on thermal management technologies for electronics in spacecraft environment
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作者 Yi-Gao Lv Yao-Ting Wang +2 位作者 Tong Meng Qiu-Wang Wang Wen-Xiao Chu 《Energy Storage and Saving》 2024年第3期153-189,共37页
Due to the rapid development of the space industry,ever higher demands are being made for the optimization and improvement of spacecraft thermal management systems.Thermal control technology has become one of the key ... Due to the rapid development of the space industry,ever higher demands are being made for the optimization and improvement of spacecraft thermal management systems.Thermal control technology has become one of the key bottlenecks that restrict the level of spacecraft design.In this paper,the thermal management technologies(TMTs)for spacecraft electronics are reviewed according to the different heat transfer processes,including heat acquisition,heat transport,and heat rejection.The researches on efficient heat acquisition include the utilization of high thermal conductance materials,the development of novel package structure based on micro-/nanoelectromechanical system(MEMS/NEMS)technologies,and advanced near-junction microfluidic cooling techniques.For the heat transport process,various heat pipes and mechanical pumped fluid loops(MPFLs)are widely implemented to transport heat from heat generation components to the ultimate heat sinks.The heat pipes are divided into two categories based on their structure layout,i.e.,separated heat pipes and unseparated heat pipes.The merits and demerits of these heat pipes and MPFLs(including the single-phase MPFL and the two-phase MPFL)are discussed and summarized respectively.In terms of the heat rejection for spacecraft,thermal radiators are normally the sole option due to the unique space environment.To meet the requirements of large heat dissipation power and fluctuated thermal environment,research efforts on the radiators mainly focus on the development of deployable radiators,variable emissivity radiators,and the combination with other techniques.Due to the fluctuated characteristics of the heat power of internal electronics and the outer thermal environment,the phase change materials(PCMs)exhibit great advantages in this scenario and have attracted a lot of research attention.This review aims to serve as a reference guide for the development of thermal management system in the future spacecraft. 展开更多
关键词 Thermal management ELECTRONICS SPACECRAFT Heat pipe mechanically pumped fluid loop RADIATOR Phase change material
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Valveless Thermally-Driven Phase-Change Micropump
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作者 王沫然 李志信 《Tsinghua Science and Technology》 SCIE EI CAS 2004年第6期688-693,共6页
A dynamic model with moving heat sources was developed to analyze the pumping mechanism of a valveless thermally-driven phase-change micropump. The coupled equations were solved to determine the pumping characteristic... A dynamic model with moving heat sources was developed to analyze the pumping mechanism of a valveless thermally-driven phase-change micropump. The coupled equations were solved to determine the pumping characteristics. The numerical results agree with experimental data from micropumps with different diameter microtubes. The maximum flow rate reached 33 μL / min and the maximum pump pressure was over 20 kPa for a 200-μm diameter microtube. Analysis of the pumping mechanism shows that the main factors affecting the flow come from the large density difference between the liquid and vapor phases and the choking effect of the vapor region. 展开更多
关键词 valveless MICROpump phase change pumping mechanism
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