Throttling a Laval Nozzle by a Vortex: an Analytical Theory

摘要

This paper presents an analytical theory for a vortex flow through a Laval nozzle. It will demonstrate that when a vortex is present the total velocity reaches sonic conditions upstream of the nozzle throat, that the axial velocity in the nozzle throat is equal to the local speed of sound and that the mass flow through the Laval nozzle depends on the vortex strength in such a way that the mass flow decreases with increasing vortex strength. The predictions of the analytical theory have been compared to the results of experiments and a numerical simulation, and it can be concluded that the analytical theory describes the characteristics of the flow very well.