Numerical Modeling of Injection of Shear-Thinning Gel Propellants Through Plain-Orifice Atomizer

Abstract

A series of axisymmetric Navier–Stokes simulations were performed to study the mean and unsteady characteristics of gel propellant orifice flows at conditions representative of rocket injectors. The rheology of the gel was simulated assuming a shear-thinning fluid behaving in accordance with the Carreau–Yasuda model. The effects of Reynolds number (flow velocity), orifice L=D, fluid rheology, and orifice inlet chamfering were studied in a series of 200 independent simulations. Unsteady conditions were observed in most cases, due to the high injection velocities typical of rocket injection conditions. The magnitude and frequency of pulsations were characterized in these cases. In general, steady flows were obtained for lower Reynolds numbers and smoother inlet (i.e., greater chamfering) conditions. Mean discharge coefficients were computed for all cases to support design studies and engineering analyses.