Controllable Solid Rocket Motor Nozzle Operations in Conditions of Limited-Amplitude Fluctuations

A nonlinear multi scale analysis of a controllable solid rocket motor operating in conditions ranging from high-amplitude fluctuations in combustion chamber to conditions lying in limit cycle is presented and the motor behavior subsequent to some relevant nozzle operations is investigated. Effects of acoustic-vorticity-entropy wave coupling, wave steepening, rotational/viscous flow losses, steep-fronted wave losses are taken into account and oscillatory energy losses in pintle-nozzle, unsteady combustion and chamber geometry changes resulting from grain regression are included. The analysis provides evidence that the unsteady energy balance and the motor wave amplitude evolution are influenced by severity, direction and sequence of nozzle operations. This open the perspective of a new concept of controlling the wave amplitude evolution and the opportunity to enlarge the operational limits of controllable solid rocket motors are discussed.