固体火箭发动机燃烧不稳定研究进展与展望

燃烧不稳定问题是今后相当长一段时间内固体火箭发动机燃烧流动领域需要解决的重要问题。由燃烧响应主导的燃烧不稳定问题具有很典型的非线性燃烧不稳定特征，是当前研究的重点与难点。采用非线性方法开展固体火箭发动机的非线性动力学分析，可以获得非线性燃烧不稳定的触发条件与稳定性区间，以及不稳定的增长过程和最终达到的极限环振荡状态。压强耦合响应、速度耦合响应、分布式燃烧、粒子阻尼和喷管阻尼是燃烧不稳定分析中重要的增益和阻尼项，在非线性燃烧不稳定分析中，这些增益与阻尼同样需要非线性表达式，需要开展精细的实验研究和理论分析，以获得更符合发动机实际工作状况的推进剂燃烧响应和铝分布式燃烧的非线性模型。深刻认识压强振荡增长过程中各阶模态间能量的传递规律，是揭示非线性不稳定触发机理和极限环形成过程的关键所在。在实验验证技术方面，需要建立起地面实验外部激励和飞试状态实际激励环境的等效分析方法，发展能够有效模拟实际飞行时发动机燃烧不稳定环境的地面等效模拟实验方法。

Advances and Prospects of Combustion Instability in Solid Rocket Motors

Combustion instability is and will be an urgent and crucial issue in flow and combustion inside solid rocket motor (SRM). Dominated by combustion response, the combustion instability is a typical nonlinear process, which is extremely complicated. Thus, the nonlinear dynamic process in SRM has to be studied by nonlinear analysis method in order to obtain the trigger of nonlinear combustion instability, the unsteady growth and the final achieved limit cycle. The predominated gain and damping terms, including pressure response, velocity response, distributed combustion, particle damping and nozzle damping, also should be described by nonlinear theory. However, the nonlinear theory is difficult to obtain, especially the one satisfies the actual motor and its operation, which relies on the sophisticated and precise experimental and theoretical study. The most important understanding of nonlinear dynamic theory is established on the energy transfer law among different acoustic modes, which is also the critical key to reveal the mechanism of triggering and generated limit cycle during unsteady combustion. The high demanding on experimental techniques falls to the technology to analogue the outside excites acted on motor during the ground static test and actual flight test. This equivalent analysis method is mean to mimic the realistic flight situation by ground test.