Nonlinear, Rotational-Acoustic Processes in Solid Rocket Engines

摘要

Solid rocket motor chamber fluid dynamics are modeled using the full NavierStokes equations. Mass injection from the sidewall of a cylinder simulates the propellant gasification. Prescribed boundary disturbances in velocity or pressure induce acoustic waves and other transients into the chamber geometry. Vorticity is generated on the sidewall from an inviscid interaction between transient pressure gradients and the fluid injected from the surface. Axisymmetric and three dimensional solutions obtained from analysis and computation are used to predict the dynamics of the co existing acoustic and rotational flows. Results suggest that intense transient vorticity is present throughout much of the chamber during a firing as long as acoustic transients are present. The rotational flow component is associated with intense transient shear stresses on the sidewall. Meanflow profiles and RMS intensity distributions are similar to those found in traditional turbulent pipe flows with injection. Traditional acoustic stability theory, based on purely irrotational flow assumptions, may describe the pressure variations in chamber models, but cannot describe the rotational component of the flow found in the present model.