Energy losses in flow through stenosed valves

Abstract

A theoretical analysis yields equations for the calculation of rates of mechanical energy loss in unsteady flow, both within a stenosed valve and in the turbulent mixing region which occurs downstream of the valve. Losses within each of the two regions can be determined by subtraction of the mechanical energy terms at inlet and outlet, but they cannot be obtained explicitly by analysis of the loss mechanisms alone. The equations are then simplified for application to a rigid walled system and re-arranged to allow the prediction of energy loss rates based upon known inflow rates and system geometry. This allows some insight into the effects upon losses of severity of stenosis, jet angle and post-stenotic dilatation. The theoretical predictions are supported by results from a model study.