Date of Award
Jeff W. Rish, III
The main objectives of this report were to perform analysis of an ideal scramjet engine, to assess the influence of fuel on endurance factor, and the possibility of lowering the starting Mach Number of the scramjet. In the first part, an ideal cycle parametric analysis was conducted on three different fuels i.e. Liquid Hydrogen (LH2), Jet Propellant 7 (JP-7), and Rocket Propellant (RP-1), taking into account their availability, physical properties, current uses, and potential uses. The detailed analysis is done largely relying on a 9 step Parametric Cycle Analysis technique to study how fuel properties influence the variation of seven important performance parameters: specific thrust, thrust-specific fuel consumption, thermal efficiency, propulsive efficiency, overall efficiency, fuel-to-air ratio, and thrust flux with flight conditions. The major factor in deciding the fuel choice was lower heating value of the fuel which directly affects thrust specific fuel consumption and fuel-to-air ratio. However, density, weight, and flash point were also considered. Fuel recommendation was made after the detailed analysis of plots and figures generated applying different scenarios in the derived equations. The second portion of the paper is dedicated to studying the possibilities of operating a scramjet at a lower startup freestream Mach number such that performance at high Mach Numbers are still retained. Recent publications indicate that the transition from subsonic to supersonic combustion is currently achievable at freestream Mach number of 5. While the engine design is one of the prime parameters in lowering the starting Mach number to 3.50. This report is primarily focused on developing insights into the possibility that lower starting Mach numbers might be achieved by carefully selecting fuels based on their properties; namely hPR and ignition temperature. It is found that the starting Mach Number of 4.30 is attainable with the current technologies but the operation of the Scramjet Engine at Mach Number 3.50 is not possible with the fuels researched and other variations in the system.
Luitel, Sumantra and Dangi, Gagan, "Analysis on fuel options for scramjet engines with the study to lower the starting mach number" (2021). Honors Theses. 1900.
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