天体物理学と航空宇宙技術

Modelling and Exhaust Nozzle Flow Simulations in a Scramjet

Abstract

Naidu KS and Bajaj DK

This project will be aimed at modelling the supersonic flow inside Scramjet engine using the Computational Fluid Dynamics CFD ANSYS Fluent. Scramjet Engine starts at a hypersonic free stream Mach no. 5.00. When pressures and temperatures become so high in supersonic flight that it is no longer efficient to slow the oncoming flow to subsonic speeds for combustion, a scramjet (supersonic combustion ramjet) is used in place of a ramjet. Supersonic flow from a nozzle that represents the exhaust nozzle of a supersonic combustion ramjet SCRAMJET is modelled. Jet from the nozzle is issued into a domain which is bounded on one side by an after body wall which is parallel to the center line of the nozzle. Shocks propagating from the nozzle exit reflect from the after body. Outflow from scramjet engines can have a significant impact on both the heat transfer and the pressure distribution on the section of the aircraft that lies downstream. Most importantly, reflecting shock waves lead to large peaks in the distributions. Two geometrical configurations for the after body are tested. Experimental values are used because this span wise region is closest to the centre of the experimental model where the three-dimensional effects are minimal. Measured values of the distribution of wall pressure and heat transfer rate along the after body are used to validate the CFD simulation.