Design of an actively valved and acoustically resonant pulse combustor for pressure-gain combustion applications

This work describes the performance and operational characteristics of a novel, actively valved, resonant pulse combustor designed for use in a pressure-gain combustion application. Three modes of operation are identified and the envelope in which the combustor will sustain resonant operation is quantified, with and without a free-stream flow imposed at the inlet. The combustor is found to be capable of operating in resonant mode with inlet valve set points from 200 Hz extending to above 290 Hz and ethylene mass flow rates from 0.1 to 0.43 g/s. The influence of inlet valve set point and fuel mass flow rate on the combustor operation is evaluated. It was found that for a given fuel mass flow rate the peak combustion chamber pressure amplitude tended to increase with decreasing valve set point frequency. For a fixed inlet valve frequency the peak combustion chamber pressure amplitude increased with increasing fuel flow rate. Also, evidence is presented indicating that the total heat release delay in the combustor is dictated by the fluid dynamic mixing induced by the inlet valve motion.