An experimental study of the ignition and combustion mechanisms in a pulse combustor. A new approach to a wide-range and low-noise pulse combustor.

A new method is proposed to obtain a wide-range and low-noise-level pulse combustion in the case of natural ventilation. It is found that the supply of a rich propane-air mixture, instead of pure fuel, which is outside the rich inflammability limit and has and equivalence ratio of 3.0 in the present experiment, can realize a higher combustion intensity of 53.4 MW/m3 and a larger turn-down ratio of 4.5 than those of the usual pulse combustors. A rather silent pulse combustion, whose noise level is 55-70dB(A) without any silencer, is possible by operating the present combustor at a 15-35% partial load. The volumetric efficiency of a pulse combustor is defined by the ratio of the total volume of fresh mixture and air supplied per cycle at NTP to the volume of the combustor, and is found to vary within the range of 4-12%, corresponding to the minimum and maximum combustion loads, respectively. As a result, the volumetric efficiency may be expected to be an important design parameter of the pulse combustor.