Numerical investigation of staged transverse sonic injection in Mach 2 stream in confined environment

Abstract

Transverse sonic injection, usually in a staged manner, in a confined environment is a necessity in the design of an efficient combustion chamber. The design requires an analysis of the mixing of the injectant with incoming stream as efficient combustion depends upon good mixing. This kind of analysis needs numerical model/simulation to assess the mixing of the two streams. To determine the suitability of an existing software package for such a study, staged transverse sonic injection into a Mach 2 stream in a confined environment is taken as a test case. The experimental conditions of McDaniel et al are reproduced for this simulation. In this experiment, staged transverse injection of sonic jet behind the backward facing step in Mach 2 stream was carried out and profiles of various flow parameters were measured. The numerical simulation solves the 3D Navier-Stokes equations with a k – ε turbulence model using the PARallel Aerodynamic Simulator PARAS3D. Computed results show a good match for injectant penetration profile although the computations predict slightly higher penetration near the orifice location. Detailed comparison of flow parameter profiles between computed and experimental data reveal that in the zone away from the injection orifice, computations predict the flow field reasonable well. However, in the vicinity of the orifice, there are some differences between experimental data and computed results. These differences could be due to non-uniform inlet profile in the experiment and/or inadequacy of the turbulence model considered in the study.