EFFECTS OF ACOUSTIC-OSCILLATIONS ON FLAME DYNAMICS OF HOMOGENEOUS PROPELLANTS IN ROCKET MOTORS

The interactions between acoustic waves and gas-phase flame dynamics o f a double-base homogeneous propellant in a rocket motor has been stud ied by means of a comprehensive numerical analysis. The formulation tr eats the complete conservation equations of mass, momentum, energy, an d species concentration, and accounts for finite rate chemical kinetic s in the gas phase and subsurface reactions. The model has been implem ented to examine the detailed flow structures and heat-release mechani sms in various parts of the motor, including microscale motions near t he propellant surface and macroscale motions in the bulk of the chambe r. Results indicate that strong interactions between exothermic reacti ons and acoustic waves occur in regions with steep temperature gradien ts due to the large activation energy of the associated chemical kinet ics. The dynamic behavior of the luminous flame plays a decisive role in determining the motor stability characteristics. Distributed combus tion response in the gas phase provides the energy for driving flow os cillations, and can be treated correctly as a combination of monopole and dipole sources based on acoustic theory.