固体推进剂非线性压强耦合响应特性实验研究

为获得固体推进剂非线性压强耦合响应特性,建立了一种非线性压强耦合响应函数的实验测量方法,分别对三种含铝复合推进剂开展了非线性压强耦合响应函数(Rp)的实验研究,获得了推进剂非线性压强耦合响应特性,深入分析了非线性压强耦合响应的影响因素。结果表明,提高触发激励压强以及改变触发激励方式,可以在T型燃烧器中模拟与实际发动机非线性燃烧不稳定相类似的非线性压强振荡特性,从而获得固体推进剂非线性压强耦合响应特性。非线性压强耦合响应函数对轴向各阶频率振荡幅值的变化较为敏感,峰值频率附近的响应值对振荡幅值的变化最为敏感,响应值变化最大,其中响应函数峰值从0.4增大到1.12。中间位置触发激励产生的二阶频率响应值与线性法长度减半对应的一阶频率响应值有明显的不同,进一步验证了线性法和非线性测量结果本质区别。

Experiments on the Characteristic of the Nonlinear Combustion Response Functions of Solid Propellants

In order to obtain the characteristics of nonlinear pressure coupling response of solid propellants, a method for measurement of the nonlinear pressure coupling response function of solid propellants was established. The nonlinear pressure coupling response functions of three formulations of aluminum propellants were obtained. The characteristics of the nonlinear pressure coupling response of propellants were also analyzed in detail. It indicates that with increase of the trigger pressure, higher-order frequency oscillations can be excited and the amplitude of nonlinear oscillation could be larged as well. By triggering at the both ends of the chamber, the oscillation is dominated by the longitudinal first-order frequency, but when triggering in the chamber middle, the oscillation is dominated by the longitudinal second-order frequency.The nonlinear pressure coupling response function is sensitive to the amplitude of the oscillation, whereas the response value near the peak frequency is the most sensitive to the change of the amplitude of the oscillation. The response value is significantly different between the second-order frequency by triggering in the chamber and the first-order frequency by triggering at end of the half-length chamber. This result just verifies the method of the linear and nonlinear methods are different.