分隔式射流通道对凹面腔内爆震起爆与反传的影响

Influence of Divided Jet Incident Channel on Detonation Initiation and In hibition of Detonation Wave Counter-Propagation in a Cavity

关键词:  爆震波  反传  凹面腔  射流  激波  脉冲爆震发动机

Key words:  Detonation wave  Counter-propagation  Cavity  Jet  Shock wave  Pulse detonation engine

摘要:

针对凹面腔内激波聚焦起爆的爆震波反传现象，采用燃料与氧化剂以分隔式通道进入凹面腔的非预混燃料入射方案，通过数值计算，主要探讨了射流入射通道截面积、各截面积比和通道数量对激波聚焦起爆的影响作用。计算结果表明:燃料/氧化剂射流入射通道截面积比为化学恰当比时，凹面腔底部的掺混程度较好，有利于点火起爆；入射通道截面积比为化学恰当比的多入射通道方案，其凹面腔底部激波聚焦起爆时温度和压力更高，相同时刻的燃烧流场其温度和压力峰值均较高，更利于增强凹面腔内的掺混程度，使燃料浓度分布均匀；小截面积比的射流入射通道，有助于增大波阻提高抑制压力反传效果，减小压力反传强度。

Abstract:

To reveal the phenomenon of detonation initiation by shock wave focusing， dividing channel of premixed fuel incident into the concave cavity was used and the fuel is separated from the oxidant. This paper mainly discusses the jet incident channel cross-sectional area， the ratio of the cross-sectional area and channel number on the influence of detonation initiation by shock wave focusing. The calculation results indicate when area ratio of incident channel is chemical appropriateness ratio， the fuel and the oxidant mixed well， which is benefit for detonation initiation. In the multiple incident channels cases， which the area ratio incident channel is chemical appropriateness ratio， the temperature and pressure of initiation point is higher the previous cases. The temperature and pressure peak of the combustion flow field at the same time are higher than the previous examples which is better for the mixing degree of the concave cavity and distributing the fuel more evenly. The ejection channel with small sectional area ratio can help increase the wave resistance and improve the anti-transmission effect and reduce the pressure reverse transmission strength. The calculation results provide guidance for experimental design.