Influence of pressure variation in decoupling chamber on heat transfer in tailpipe of self-excited pulse combustor

Decoupling chamber is an important component of a pulse combustor which is not only for noise elimination, but also to ensure the acoustics boundary conditions at the exit of tailpipe as to maintain the performance of the whole combustor. Thus, a decoupling chamber pressure control system was designed and installed at the end of the tailpipe of a valveless self-excited pulse combustor. The relative pressure in the decoupling chamber was controlled from about -10 kPa to 10kPa through a blower, and the influence of pressure variation on the heat transfer in tailpipe was investigated. Experimental results showed that when the pressure in decoupling chamber is higher or lower than atmospheric pressure, the heat transfer coefficient in tailpipe would be increased, the heat transfer coefficient in tailpipe is relatively higher when pressure in decoupling chamber is lower than atmospheric pressure, and both the magnitude of pressure amplitude and the velocity ratio in the combustor can reflect the heat transfer coefficient in tailpipe.