NACA-TN-3860

Abstract

Generalized expressions and charts which depend on the shock Mach number, the initial state of the gas, and an enthalpy parameter (the enthalpy divided by the ratio of the pressure to the density) are presented for the temperature, pressure, density and flow velocity behind a shock wave. The charts and an enthalpy plot for dissociated air have been used to find the relation in graphical form between the degree of dissociation in air and the enthalpy parameter. Plots are presented of the resulting dependence of the flow variables on the degree of dissociation. <br>Because the chemical reaction rates needed to predict the dependence of degree of dissociation on distance behind the shock are not known, order-of-magnitude estimates of their values have been used in a numerical example, the purpose of which is to illustrate the use of reaction-rate equations to predict relaxation time and distance behind the shock front.