Helium Injection Into the Boundary Layer at an Axisymmetric Stagnation Point

Abstract

Abstract : A theoretical analysis of the boundary layer at an axisymmetric stagnation point with large rates of helium injection is presented. The exact stagnation point boundary layer equations are integrated numerically with an approximate representation of the gas properties. The new treatment of the two-point boundary value problem that arises is shown to be useful for various boundary layer and mixing problems. The exact solutions indicate that for large rates of injection the boundary layer can be represented by a thick, inner layer of constant shear, temperature and composition and by a relatively thin outer region in which the flow variables adjust to their free-stream values. An inviscid flow model is shown to lead to accurate predictions of this shear layer and will thus provide sufficiently accurate profiles forfagnation point mass transfer. The heat transfer to the stagnation point is also considered. Tabulations of the solutawlconditions and injection rates are given in an appendix. (Author)