Real gas normal shock waves with the redlich-kwong equation of state

Abstract

The calculation of the normal shock wave of real gases poses serious difficulties either because of the complexity of the exact thermal and caloric equations of state of the real gas considered, or because of the total lack of these equations. The present work describes a method for the prediction of the normal shock wave of real gases, which is based on the Redlich-Kwong generalized equation of state. The method involves iterative solution of the energy conservation equation for one of the state variables, while all the other variables are calculated explicitly. The method is applicable to real gases for which no detailed thermodynamic data are available, as the only gas-dependent information required is the values of pressure and temperature at the critical point and the heat capacity in the ideal gas state (pressure approaching zero). Because of the short computational time, the method is recommended even in the case of real gases for which the exact thermal and caloric equations of state are available. Applications have been made in the case of real air, for which exact shock wave values are available for comparison with the present method. The agreement is very good in a wide range of conditions.