Scramjet Design and Analysis for Experimental Investigation on Supersonic Combustion with Energy Addition

摘要

This work shows preliminary results of the design and analysis of a scramjet inlet and combustor for heat addition rate studies. The scramjet design Mach number was 7.0 at an altitude of 30 km, using hydrogen as fuel, with a design fuel-air equivalence ratio of 0.15. The analysis focuses on how the heat addition rate influences key combustor exit properties. In the aerodynamic design of the scramjet, we considered the following steps: i) in the inlet, air flow with calorically perfect gas behavior, inviscid flow, so that oblique Shockwave relations can be used, also the incident Shockwave of the compression system focuses in the cowl leading edge (shock-on-lip) and the reflected Shockwave focuses at the combustion chamber entrance (shock-on-corner), ii) boundary layer is taken into account by a simple methodology; iii) combustor at constant pressure and constant area approaches are studied; iv) combustion process in chemical equilibrium is calculated considering a Gibbs energy minimization process, with quasi-one-dimensional flow assumption and with friction; and v) fuel injection effects were simplified by using an empirical model to estimate the mixing efficiency.