Effects of Tube Wall Thickness on Combustion and Growth Rate of Supersonic Reacting Mixing Layer

Abstract

The study of supersonic reacting shear layer has been paid great attention to further understand flow characteristics and mechanism of the engine combustion process. However, most past studies remain narrow in focus dealing only with infinitely small tube thickness or fixed ones which neglects the complex flow structures reflecting some general features of scramjet engine mixing and combustion process. In the present study, supersonic reacting mixing layer has been studied under different tube thickness. Numerical simulations have been carried out with CFD++ 14.1 to solve the Reynolds averaged equation on the Evan’s configuration which is closed by Menter’s Shear Stress Transport turbulence model and finite reaction rate chemical kinetic model. The flow field evolution, mixing layer growth and combustion ignition are the major focus of current study. The obtained results show that the existence of finite tube thickness brings unique flow field characteristic such as expansion fans and shock systems which is not included in the tradition simplified analysis of reacting shear with infinitesimal tube thickness. The tube thickness has a positive effect on growth of mixing layer and ignition delay that 50% of decrease in ignition delay has achieved by enough tube wall thickness.