Investigation of the Kelvin-Helmholtz Instability Process in Liquefying Hybrid Rocket Fuels

Abstract

The combustion behavior of paraffin-based hybrid rocket fuels has been investigated with different optical techniques in the framework of this research. Combustion tests were conducted in a 2D single-slab burner at atmospheric conditions. High speed videos and CH* chemiluminescence imaging were performed and analysed in detail by using an automated video evaluation routine. Two different decomposition techniques (Proper Orthogonal Decomposition and Independent Component Analysis) were applied to the scalar field of the flame luminosity and the flame characteristics of these fast burning fuels were computed. The fuel viscosity and oxidizer mass flow have been varied in order to study the influence of these parameters on the liquid layer instability process. Wave-like structures can be seen throughout the whole combustion process in all the performed tests. The flame topology and location within the boundary layer is found to depend on the choice of the fuel and oxidizer mass flow.