Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Scramjet thrust analysis based on the variation of its compression section angle
Submission Author:
Laura Carolina Monteiro dos Santos Rodrigues da Silva , SP
Co-Authors:
Laura Carolina Monteiro dos Santos Rodrigues da Silva, Valéria Leite
Presenter: Laura Carolina Monteiro dos Santos Rodrigues da Silva
doi://10.26678/ABCM.COBEM2023.COB2023-1036
Abstract
In the search for a more efficient and affordable way to access space, the supersonic combustion ramjet (scramjet) propulsion systems have been considered as an alternative to the rocket propulsion systems, since the transport of oxidant is unnecessary in the dense atmosphere. As this is a technology still under development, all the new tools and theories for the studies of the vehicle geometry are good to contribute to evaluate the behavior of the thermodynamics properties of the air in relation with some changes in the geometric variables. In this context, this work aims to investigate the variation in the behavior of the net thrust of a scramjet engine generated by changing the angle of a single ramp of the compression section. The objective is to analyze the influence in the provide vehicle thrust, at its exit, by moving a single ramp at its frontal part. A two-dimensional scramjet vehicle with planar symmetry is presented in this work. The geometry is designed so that the Mach number and static temperature at the combustor inlet promote spontaneous ignition of the fuel. The oblique shock wave theory is adopted to calculate the properties in the compression section. Rayleigh’s theory is considered in the combustion chamber in order to calculate the heat addition considering a constant area section. Finally, the area ratio theory is applied in the expansion section in order to calculate the properties at the exit of the scramjet engine. In this work, viscous effects are not considered, and two approaches are applied: calorically perfect gas and gas in chemical and thermodynamic equilibrium, using the polynomial fit method of Tannehill and Mugge, in order to evaluate the thrust variation. Although this method can be applied to scramjets with different numbers of ramps in the compression section, different flight speeds and altitudes, a case with three compression ramps, for a vehicle flying at a speed equal to Mach 6 and altitude of 30 km is considered in this analysis. As a result, it is expected that the net thrust will be the highest possible one for the angle and the geometry under analysis.
Keywords
Oblique Shock Wave, Hypersonic Flow, Scramjet Engines
