The design and performance evaluation of scramjets derived from quasi-1D flowfields

Literature surveys conducted as part of this research effort revealed that the morphing RAM-SCRAMJET model^1-3, has many attractive engineering characteristics, and as such, it is worthy of an independent and realsitic engineering evaluation. The objective of this effort is to improve on the RAM-SCRAMJET model by incorporating real-world effects into the design process. In accomplishing this goal, a quasi-one-dimensional flow field solver with capabilities of modeling the real-world effects of the scramjet aero-thermodynamic environment was developed. The real-world effects considered in this study are as follows: ‘area change’, ‘friction’, ‘heating’ and ‘chemistry’. The newly developed tool was used to inversely design scramjet configurations with optimum thrust characteristics and to analyze their performance. The scramjet performance evaluations were conducted through the use of a 4^th order Runge-Kutta method for solving systems of differential equations. In principle, the new scramjet configuration design and analysis procedure allows for the flow field evaluation within arbitrary shaped ducts in which the influences of ‘area change’, ‘friction’, ‘heating’ and ‘chemistry’ may be of importance. To date, engineering studies were conducted in the Mach number range of 4 through 12. The results showed the improved RAM-SCRAMJET code performs well at low Mach numbers, but did not compare well with independent efforts in the high Mach number regime. At this stage, the difference is attributed to the fact that the current flow field solver cannot predict the effects of heating well. Efforts to improved on this capability are currently being pursued and will be reported in the final paper.