High-Enthalpy Nonequilibrium Nozzle Flow of Air: Experiments and Computations

Abstract

An investigation of the nozzle expansion of air from a reservoir at high specific enthalpy is presented. The objective is to test the chemical models assumed in nonequilibrium numerical computations and obtain a better understanding of the conditions at the nozzle exit as a function of the reservoir conditions. Static pressure measurements at the nozzle exit are performed in the T5 free-piston shock tunnel at the California Institute of Technology and compared with computations using DPLR CFD code which solves the chemically reactive Navier Stokes equations. Experiments are performed at four conditions with a range of stagnation pressures between 20 and 60 MPa and stagnation enthalpies between 10 and 17 MJ/kg. The measured static pressures are between 10% to 17% lower than those computed which seems to indicate that less recombination occurs in the experiment.

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