A computational study of turbulent reacting flowfields for scramjet applications.

摘要

A computational model has been developed to solve the Favre-averaged Navier-Stokes equations coupled with transport equations for individual chemical species. Turbulence closure is achieved using three different two-equation turbulence models, and an assumed Gaussian probability density function (PDF) for temperature is employed for closure of the chemical production rates. Two axisymmetric combusting flowfields are used for model validation: a subsonic bluff-body stabilized methane flame, and a supersonic hydrogen flame. Results are also presented for a three-dimensional flame/shock wave interaction experiment with comparison to wall static pressure, pitot pressures, and Schlieren photographs. Contrary to experimental findings, calculations show the flame to be stabilized by the passage of an oblique shock wave through the fuel jet, indicating that a better characterization of the ignition process is required. Both the combusting and mixing flowfields are found to exhibit a high degree of three-dimensionality, with stream-wise vortices providing the primary mechanism for large scale fuel-air mixing.