Identification of chemical and vibrational relaxation regimes in rocket nozzle flow via a quasi-linear formulation

Abstract

A quasi-linear formulation is proposed for high-speed finite-rate chemically reacting mixtures of imperfect gases, i.e. thermally perfect gases with specific heat varying with temperature, as an extension of a previously developed formulation for perfect gases. The form is suitable for application of accurate and fast algorithms. In particular, the resulting equations keep the same formalism already derived for reacting mixtures of perfect gases, thus indicating the potential for a straightforward extension of existing computational algorithms. In order to assess the applicability of the approach, the assumption of vibrational equilibrium needs to be verified. Accordingly, vibrational, as well as chemical, relaxation regimes are checked in a high expansion ratio rocket nozzle, indicating that the assumption under consideration is fully warranted. The effect of nozzle size on engine performance is also predicted.

Keywords

chemically reacting flows transonic flow

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