Numerical Model to Predict Unsteady Cavitating Flow Behavior in Inducer Blade Cascades

Abstract

The cavitation behavior of a four-blade rocket engine turbopump inducer is simulated. A two-dimensional numerical model of unsteady cavitation was applied to a blade cascade drawn from an inducer geometry. The physical model is based on a homogeneous approach of cavitation, coupled with a barotropic state law for the liquid/vapor mixture. The numerical resolution uses a pressure-correction method derived from the SIMPLE algorithm and a finite volume discretization. Unsteady behavior of sheet cavities attached to the blade suction side depends on the flow rate and cavitation number. Two different unstable configurations of cavitation are identified. The mechanisms that are responsible for these unstable behaviors are discussed, and the stress fluctuations induced on the blade by cavitation instabilities are estimated.