Numerical Simulations of Vortex-Acoustic Coupling in Two-Phase Flow of VKI Motor

The vortex-acoustic coupling caused by flow instability is one of the main gain factors that result in combustion instability of motors. Through taking the VKI (Von Karman Institute for Fluid Dynamics) motor as a reference model and introducing the aluminium oxide condensed particles, this paper focused on the influence study of obstacle vortex shedding on the pressure oscillation under two-phase interaction by applying Large Eddy Simulation (LES) method. Based on the analysis of two-phase flow characteristics and acoustic features in the combustion chamber, the paper revealed influences of the aluminium oxide condensed particles in VKI motor on the law of vortex movement, the pressure oscillation frequency and the pressure amplitude. The results show that, under the action of two-phase flow the vortex movement is not as clear as the one in pure-gas flow, the vortex structure becomes chaotic. Meanwhile, the dominant pressure oscillation frequency of the VKI combustor decreases, and the corresponding pressure amplitude also slightly decreases.