The numerical analysis of combustion performance of a wedge shaped strut-based scramjet combustor

Abstract

The combustion performance of hydrogen fueled supersonic ramjet combustor has been computationally analysed. For the need of comparison, DLR Scramjet model of German Aerospace Center (DLR) has been taken into consideration. Off design analysis has also been conducted through the same model to see the appropriate changes. Ansys 14.0 fluent solver has been used to solve the two dimensional DLR Scramjet model with the help of Reynolds Averaged Navier-Stokes (RANS) equation. To have the reasonable accurateness of turbulent flow, RNG k-ε two equation model has been chosen. The good agreement can be seen between present computation and the experiment data in open literature. Shock incident point follows the same pattern as previous experimentations and this can also be recognised in contour plots. To explore the variation behind the combustion performance by means of two selected parameters i.e. Mach number and temperature of incoming free stream air. This variation in the supersonic combustor is found helpful in terms of mixing length, shock wave behavioural strength, mixing efficiency and combustion efficiency. The changes in air speed lead to alter the incident location points of the shock waves. As the free stream air speed is getting higher, the appearance of fuel from the strut face became parallel in nature with air. Smallest mixing length of 26 mm is accomplished. Ignition delay between fuel entrainment and start of combustion did not take place in cases with Mach number 2.6, 2.8 and 3.0. However the superior combustion performance among all the selected cases is seen at the free stream air Mach number 3.0.