The Design of Scramjet Configurations for Optimal Operational Temperature and Overall Propulsion Efficiency

The objectives of this research effort were to inversely derived and analyzed scramjet configurations at selected design points along the engines expected flight corridor. The design process implemented herein allowed for the derivation of realistic scramjet geometries, as real-world effects were incorporated into the design process. Once developed, the technical goals were to identify the scramjet design parameters, and evaluate their relationship relative to the scramjet overall performance. In efforts to accomplish these goals, a quasi-one-dimensional flow field solver with capabilities of modeling the real-world effects pertinent to scramjets operations was developed. The quasi-one-dimensional flow field solver is based on the Runge-Kutta 4 order scheme for solving systems of differential equations. In principle, the solver allows for the flow field evaluation within arbitrary shaped ducts in which the influences of ‘area change’, ‘friction’, ‘heating’ and ‘chemistry’ are of importance. The quasi-one-dimensional flow field solver was used to analyze and optimize the overall scramjet thrust performance in the Mach number range of 4 through 8. Technical efforts were geared towards evaluating the performance of this new class of scramjets with existing scramjet models, report on any new findings and suggest recommendations for possible improvements to existing designs. The technical goals were accomplished. In this effort, star-shaped scramjet configurations with morphing capabilities were inversely carved from 2D planar flow fields. These configurations were successfully analyzed through the use of the quasi-one-dimensional solver. The preliminary results obtained from this study supported the fact that hypersonic flight performance requirements will certainly dictate the use of a translating center body and associated outer ‘clamshell’, which means, configurations very similar to the ones derived in this study will play an important role. In general, the preliminary outcomes of this research can be classified into two categories: First, the propulsion system design and assembly process led to the discovery of engineering parameters that directly influence the aerodynamic performance of the resulting configuration. These parameters were manipulated to generate configurations with superior thrust and Isp characteristics. Second, the design information needed to develop routines for a follow-on optimized ‘ramjet-to-scramjet configuration’ were generated.