Variation of the pulse combustion characteristics with pressure in decoupling chamber

This paper described experimental results of combustion oscillations produced in a self-excited pulse combustion system. It is shown that combustion oscillations can be produced with a steady supply of fuel and air, requiring no mechanical or aerodynamic valves, and it can be controlled by adjusting the pressure in decoupling chamber as well. A blower was applied for adjusting the relative pressure from about -10 to 10 kPa in decoupling chamber. The temperature and the pulse pressure distribution along the axial direction of the pulse combustor, and the components of flue gas in the exit of the tailpipe were measured. The results show that when power of the combustor and equivalence ratio are constant, the temperature in combustion chamber and tailpipe, mean pressure in combustion chamber and the thermal efficiency of the combustor increase with the increase of the pressure in decoupling chamber; when the pressure in decoupling chamber is higher or lower than the atmospheric pressure, the heat transfer coefficient in tailpipe can increase by 10% to 28%.