振荡管内激波与乳化液滴相互作用及其耦合机制研究

The rapid atomization and mixing process of the fuel droplets in the oscillating tube with unsteady pressure disturbance is the key to the stable initiation of the new power plant such as the Internal Combustion Wave Rotor (ICWR) and the Pulse Detonation Engine (PDE). This project aims to combine the advanced measurement technology and high-precision numerical simulation to study the mechanism of droplet broken and micro-explosive atomization process with the interaction of the shock wave and emulsion liquid fuel droplets in an oscillation tube. The RM (Richtmyer-Meshkov) instability induced by shock wave was analyzed by advanced optical observation methods (including PDA, high-speed photography / laser image, NPLS, etc.) and VOF interface capturing method combined with large eddy simulation. As well as the unstable broken, secondary atomization by the droplet microexplosion, droplet ultrafast evaporation and turbulent mixing process. The clear image and the dynamic change process of the flow field wave system, velocity distribution and turbulence large scale structure can be obtained, but not limited to these results in the atomization area. The effects of shock wave and fuel droplet properties on the broken process were investigated, and the characteristics of droplet microexplosion under the action of superhigh heat transfer were studied. The mechanism of droplet unstable broken and the secondary atomization because of mircoexplosion is clarified, which is a new approach to explore the stable initiation of the new power plant such as ICWR and PDE.

振荡管内非定常压力扰动环境下燃料液滴的快速雾化及混合过程是内燃波转子及脉冲爆震发动机等新型动力装置稳定起爆的关键。本项目拟采用先进的测量技术与高精度的数值模拟相结合的方法，研究振荡管内激波与乳化液体燃料液滴相互作用时的分散破碎及微爆雾化过程中的机理问题。通过综合运用先进光学观测手段（包括PDA、高速摄影/激光纹影、NPLS等）以及VOF运动界面捕获方法与大涡模拟相结合的数值手段，对激波诱导液滴的RM（Richtmyer-Meshkov）不稳定性破碎、液滴微爆二次雾化、液滴超急速传热蒸发以及湍流混合过程进行研究。获得雾化区域的流场波系、速度分布、湍流大尺度结构等的清晰图像及动态变化过程。考察激波、燃料液滴物性参数对破碎过程的影响，研究超急速传热条件下的液滴微爆特性。力图明晰乳化液体燃料液滴不稳定性破碎与液滴微爆二次雾化的机理，为内燃波转子及脉冲爆震发动机等新型动力装置的稳定起爆探索新的途径。

非定常燃烧技术由于具有自增压特性，且燃烧效率接近于等容燃烧过程，基于爆震循环的推进系统正越来越受到研究者的关注。相比于气体燃料，液体燃料必须经过雾化、蒸发和掺混等物理过程，才能形成可爆混气，燃料液滴的快速雾化依然是内燃波转子及脉冲爆震发动机研究中的技术难点。为进一步阐明爆震燃烧室中激波与液滴的相互作用机制及乳化燃料液滴的“微爆”强化过程，本项目采用数值方法考察激波、燃料液滴物性参数对破碎过程的影响，研究超急速传热条件下的液滴微爆特性，力图明晰乳化液体燃料液滴不稳定性破碎与液滴微爆二次雾化的机理。通过数值模拟分析了不同凹腔结构内在不同初始扰动涡强度下激波聚焦特性，并分析了激波聚焦点能量受粘性耗散的影响，为内燃波转子及脉冲爆震发动机等新型动力装置的稳定起爆探索新的途径。