A Reduced-Order Simulation Methodology for Nanosecond-Pulsed Plasmas in a Backward-Facing ‎Step Supersonic Combustor Configuration

Abstract

This work presents a simplified methodology for coupling the physics of a nanosecond-pulsed discharge to the process of supersonic combustion within a backward-facing step combustor. The phenomena of plasma and supersonic combustion are simulated separately and then coupled. Based on results reported in the literature, a zero-dimensional plasma model is built, considering only the kinetic effects of the nanosecond-pulsed discharge. A set of Favre-averaged compressible Navier-Stokes equations, as well as finite rate chemistry, is used in the combustion model and solved with a control-volume based technique. The plasma-supersonic combustion coupling process only considers the discharge as a source of O and H radical species. The calculated densities of the radicals generated during each pulse from the plasma model are periodically seeded inside the domain of the combustor. The proposed methodology is used to perform a novel simulation that involved the application of plasma to a well-known supersonic combustion experiment. The temperature and species concentration contours show that the proposed methodology captures the main effects of the nanosecond-pulsed discharge on supersonic combustion. The ignition delay time is reduced when the plasma discharge was applied. In addition, the simulations show that the plasma causes a supersonic low-enthalpy mixture to ignite, confirming the capability of the methodology.

Keywords

• plasma assisted combustion
• nanosecond pulsed discharge
• scramjet
• supersonic flow
• cfd