自由活塞发动机进气及压缩终了缸内气体流动特性分析

为组织好自由活塞发动机缸内气体流动,以提高可燃混合气混合质量,进而改善发动机燃烧质量,依据自由活塞运动特点,建立自由活塞发动机系统仿真模型,采用数值模拟方法对进气冲程和压缩冲程缸内流场进行仿真研究。分析结果表明,在进气冲程和压缩冲程时间之和一定情况下,进气冲程活塞运动快慢对进气终了缸内工质运动强度影响不大;快速压缩可提高压缩终了缸内工质运动强度,压缩终了单位质量湍动能在压缩冲程时间占进气冲程时间与压缩冲程时间总和45%时高达4.883 m2/（s2·kg）,比压缩冲程时间占进气冲程时间与压缩冲程时间总和55%时高40%。采用慢进气快压缩的活塞运动规律,增大了压缩终了缸内流场运动强度,有利于火焰...

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Bibliographic Details
Published in农业工程学报 Vol. 31; no. 8; pp. 61 - 67
Main Author 尹凝霞 常思勤
Format Journal Article
LanguageChinese
Published 广东海洋大学工程学院,湛江,524088%南京理工大学机械学院,南京,210094 2015
Subjects
数值分析
模型
活塞运动
流场分析
自由活塞发动机
models
自由活塞发动机
数值分析
free piston engines
模型
numerical analysis
piston motion
流场分析
flow field analysis
活塞运动
Online AccessGet full text
ISSN1002-6819
DOI10.3969/j.issn.1002-6819.2015.08.010

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Summary:为组织好自由活塞发动机缸内气体流动,以提高可燃混合气混合质量,进而改善发动机燃烧质量,依据自由活塞运动特点,建立自由活塞发动机系统仿真模型,采用数值模拟方法对进气冲程和压缩冲程缸内流场进行仿真研究。分析结果表明,在进气冲程和压缩冲程时间之和一定情况下,进气冲程活塞运动快慢对进气终了缸内工质运动强度影响不大;快速压缩可提高压缩终了缸内工质运动强度,压缩终了单位质量湍动能在压缩冲程时间占进气冲程时间与压缩冲程时间总和45%时高达4.883 m2/（s2·kg）,比压缩冲程时间占进气冲程时间与压缩冲程时间总和55%时高40%。采用慢进气快压缩的活塞运动规律,增大了压缩终了缸内流场运动强度,有利于火焰传播。该研究为组织缸内气体流动提供参考,对提高发动机性能具有重要意义。
Bibliography:Compared with the conventional four-stroke engine, the four-stroke free piston engine has benefits in terms of high efficiency, weight reduction, and variable compression ratio and expansion ratio. At the same time, both the freedom and convenience control of the movement of the four-stroke free piston are improved. Without the restriction of the crankshaft, the movement of the piston that is determined by the interaction of a number of forces acting on the mover, makes it possible to further improve the performance through design optimization and technology innovation. Based on the dynamics principle of the free piston engine, the dynamic model of the free piston is built. The dynamics of the free piston assembly obeys Newton’s second law. On the basis of the movement of the free piston, the geometrical model and the simulation model of the compressed natural gas （CNG） free piston engine are established. With the help of the general fluid computing platform, the module of the free piston movement that can be
ISSN:1002-6819
DOI:10.3969/j.issn.1002-6819.2015.08.010