An Experimental Study of Transient Flows in Pulse Combustors

The purpose of this investigation was to experimentally characterize a pulse combustor with respect to ambient conditions, pressure amplitudes, wall temperature, combustor geometry and type of centerbody used. The wall temperatures were recorded and the pressure variation was obtained using a sampling rate of 10,000 readings per second. These parameters were recorded for two different tailpipe lengths and centerbodies, and for different ambient conditions. Power spectrums were then obtained from the pressure variations. These spectrums displayed the peak amplitudes and the frequencies at which they occurred. The experiment showed distinct repeatability. It was concluded that combustor displayed the steady, pulsing and flame-out modes. The pulse combustor behaved just like any other combustion engine in terms of its efficiency with respect to ambient temperature and pressure. It was deduced that the inlet pressures dictated the achievement of the pulsing mode. The effect of increasing the length of the tailpipe proved advantageous to a certain limit. A change in the centerbody proved advantageous in some cases and had no effect in others