Two-Phase Vorticoacoustic Flow Interactions in Solid-Propellant Rocket Motors

Two-phase e ow interactions with vorticoacoustic oscillations in simulated solid-propellant rocket motors have been studied numerically using a combined Eulerian ‐Lagrangian approach. The model accommodates the complete conservation equations in axisymmetric coordinates and, consequently, allows for a detailed treatment of particle dynamics and unsteady motor internal e ow evolution. Emphasis is placed on the interphase coupling between the gas and particle e elds under the ine uence of acoustic excitation and turbulence dispersion and the intraphase interactions among particles such as collision and coalescence. The study demonstrates that acoustic oscillations provide additional mechanisms to transfer energy from periodic motions to turbulence, leading to an enhanced level of turbulence intensity and an early transition from laminar to turbulence. On the other hand, turbulence-induced eddy viscosity tends to suppress vortical e ow motions caused by acoustic waves. The thermal and momentum relaxation times of particles, along with acoustic characteristic time, play an important role in dictating thetwo-phase e ow interactionswith oscillatory motorinternal e ows. Amaximum attenuation of acoustic waves occurs when those timescales become comparable. Small particles, however, usually exert greater ine uence on thedispersion ofacousticwave through its effectivemodie cation of mixturecompressibility. Particleintraphase interactions are signie cant mainly in situations with a wide range of particle size distribution.