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基于大涡模拟方法的二冲程发动机缸内冷态流场的模拟研究
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作者 王传毅 朱宏 肖进 《内燃机与动力装置》 2014年第1期14-20,共7页
应用大涡模拟方法对一台二冲程发动机缸内冷态湍流流场进行了三维瞬态数值分析。探索缸内流场的速度、压力及温度的变动情况,并与PIV流场测试结果进行了对比。三维模拟的缸压曲线与试验及一维模拟均吻合较好,但在速度概率密度函数方面... 应用大涡模拟方法对一台二冲程发动机缸内冷态湍流流场进行了三维瞬态数值分析。探索缸内流场的速度、压力及温度的变动情况,并与PIV流场测试结果进行了对比。三维模拟的缸压曲线与试验及一维模拟均吻合较好,但在速度概率密度函数方面与试验存在一定差异。模拟结果表明:本文建立的三维模型能够自然再现缸内冷态流动的随机大尺度涡流情况,模型可靠有效。模拟能够较好地反应火花塞位置附近速度随机波动情况,其结果对于后续研究缸内大尺度涡流对燃烧循环变动的影响机理具有一定的指导意义。 展开更多
关键词 二冲程 大涡模拟 大尺度涡流 STAR-CD
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LPG发动机缸内流场的数值模拟研究
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作者 李子豪 《汽车维修》 2017年第11期8-11,共4页
液化石油气(LPG)具有辛烷值高、抗爆性好、成本低等优点,已作为点燃式发动机的代用燃料得到推广和应用。在LPG发动机整个工作循环中,缸内气体充量始终进行着极其复杂而又强烈瞬变的湍流运动,这种湍流运动决定了各种量在缸内的输运和空... 液化石油气(LPG)具有辛烷值高、抗爆性好、成本低等优点,已作为点燃式发动机的代用燃料得到推广和应用。在LPG发动机整个工作循环中,缸内气体充量始终进行着极其复杂而又强烈瞬变的湍流运动,这种湍流运动决定了各种量在缸内的输运和空间分布,对缸内混合气形成、火焰传播和燃烧质量及缸内传热都具有直接影响。本文通过计算机数值计算的方法,对一款LPG发动机缸内流场演变过程进行定量描述。 展开更多
关键词 缸内流场 演变过程 发动机 进气过程 LPG 进气门 燃烧过程 压缩冲程 大尺度涡流 火花塞 射流剪切层
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Comparison of two types of persistent heavy rainfall events during sixteen warm seasons in the Sichuan Basin 被引量:3
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作者 Yuanchun Zhang Jianhua Sun +3 位作者 Luqi Zhu Huan Tang Shuanglong Jin Xiaolin Liu 《Atmospheric and Oceanic Science Letters》 CSCD 2021年第6期48-53,共6页
Based on hourly precipitation from national surface stations,persistent heavy rainfall events(PHREs)over the Sichuan Basin(SCB)are explored during the warm season(May to September)from 2000 to 2015 to compare synoptic... Based on hourly precipitation from national surface stations,persistent heavy rainfall events(PHREs)over the Sichuan Basin(SCB)are explored during the warm season(May to September)from 2000 to 2015 to compare synoptic circulations and maintenance mechanisms between different PHRE types.There are two main types of PHREs:one is characterized by a rain belt west of 106°E over the SCB(WSB-PHREs),and the other features a rain belt east of 106°E over the SCB(ESB-PHREs).In total,there are 18 ESB-PHREs and 10 WSB-PHREs during the study period.Overall,the rain belts of WSB-PHREs are along the terrain distribution east of the Tibetan Plateau,while the precipitation intensity of ESB-PHREs is stronger.For the two types of PHREs,the shortwave trough over the SCB and the western Pacific subtropical high act as their favorable background environments,particularly for ESB-PHREs.The water vapor of WSB-PHREs is mainly transported from the South China Sea,whereas for ESB-PHREs the South China Sea and Bay of Bengal are their main moisture sources.The composite vorticity budgets of southwest vortices during their mature stage indicate that the convergence effect is a dominant factor for maintaining the two types of PHREs,and the strong vertical vorticity advection is also favorable,but the relative contribution of vertical advection is larger for WSB-PHREs. 展开更多
关键词 Southwest vortex Persistent heavy rainfall event Large-scale circulation Vorticity budget
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