Precise method for calculation of viscous flows in Lavale nozzle

A new model for numerical computation chemical-reacting viscous flows through variable cross section channel with smoothly curved wall is proposed. It is based on the full system of Navier–Stokes equations, which has been written in the adaptive system of orthogonal curvilinear coordinates attached to channel geometry. The simplified equations have been deduced. The model improves the well-known slender channel approximation in case of curved channel: the new terms have been brought into the equations by the nonzero curvature of a wall. Numerical combined march method is worked out providing calculations both subsonic and supersonic flows. The critical flow through supersonic nozzle is calculated with controlled accuracy.