A modular analysis of the SCRamjet combustion chamber

A numerical model of the dual mode SCRamjet engine combustor is developed. Emphasis is placed upon identifying the important flow phenomena present in the SCRamjet engine and integrating them into the numerical procedure in as simple a fashion as possible. The model is based on the one dimensional Euler equations which are written with general source terms. The combustor flow field is subdivided into one dimensional streams and the important mechanisms of turbulent mixing and viscous and thermal wall effects are incorporated as mass momentum, energy, and chemical species fluxes between the streams via the source terms. The turbulent fluid mixing is calculated using equations derived from experiments in shear flow mixing and the levels of both large scale and small scale (i.e. molecular) mixing are considered. The wall effects are calculated using either a boundary layer approximation or friction and heat transfer coefficients depending on which method is more appropriate. Chemical reaction is accounted for in the equation of state assuming the fluid is in chemical equilibrium. The numerical method is an explicit finite volume formulation with an adaptive grid and the inviscid fluxes are calculated using a Van-Leer flux vector splitting scheme. The engine model is verified by comparison with mixing experiments which have been conducted under conditions similar to those expected in the SCRamjet combustor. Finally, the model is used to predict the flow field in a model SCRamjet combustor. A description of the model combustor and some basic theory on dual mode engine operation is also included.