| Although the concept of the supersonic combustion ramjet (scramjet) is not new, the maximum flight speed that can be achieved by this power plant has not been established to date. The purpose of this dissertation is to determine the maximum flight speed at which the scramjet is capable to produce enough thrust to overcome its own external drag. In order to determine the maximum flight speed, the net thrust developed by the scramjet is compared to the external drag acting on it for flight Mach numbers 7 to 25. Using an ideal engine cycle, it will be shown that the maximum flight Mach number of the scramjet is approximately 23. When more realistic assumptions are used to include the effects of stagnation pressure loss due to viscous effects and combined friction at the wall of the combustion chamber, the maximum flight Mach number which the scramjet engine may produce is about 12. In this analysis, the flow at the end of each of the engine components is assumed to be one dimensional and in chemical and thermodynamic equilibrium. Performance losses due to incomplete mixing and combustion of fuel and air have not been considered. |
