Numerical analysis of transient combustion response to acoustic oscillations in axisymmetric rocket motors

摘要

A numerical analysis of unsteady motions in solidudrocket motors with a nozzle has been conducted. Theudformulation treats the complete conservation equationsudfor the gas phase and the one-dimensional equations inudthe radial direction for the condensed phase. A fullyudcoupled implicit scheme based on a dual time-steppingudintegration algorithm has been adopted to solve the governing equations and associated boundary conditions.udAfter obtaining a steady state solution, periodic pressureudoscillations are imposed at the head end to simulate acoustic oscillations of a traveling-wave motion inudthe combustion chamber. The amplitude of the pressureudoscillation is 1.0 % of the mean pressure and theudfrequency is 1790 Hz, corresponding to the twice of theudfundamental frequency of the chamber. Magnitude andudphase of pressure and axial velocity fluctuations are influenced by the upstream reflecting wave from the nozzleudwall. Axial velocity near surface region oscillatesudin phase advance manner with reference to the acousticudpressure. Large vorticity fluctuations are observed inudnear surface region. The mass-flow-rate at the nozzleudexit periodically oscillates with a time delay comparedudto the imposed pressure oscillations at the head end.