Heat Transfer in Helmholtz-Type Valveless Self-Excited Pulse Combustor Tailpipe

Tailpipe heat transfer characteristics of Helmholtz-type valveless self-excited pulse combustor was investigated by experiments. The results show that heat transfer coefficient in the tailpipe increases with pressure amplitude and frequency. Heat transfer coefficient of oscillating flow is about 2 to 5 times of steady flow at the same mean Reynolds number. A heat transfer correlation for the oscillating flow in the tailpipe of the pulse combustor, Nû = -0.0022Re̅^3/4 (1 - 18.909U_m + 147.27 fd/U̅) is proposed using appropriate micro-scales model under the experimental conditions. The correlation is least-squares fitted to the experimental data. The agreement between the experimental Nusselt number and the regress Nusselt number is good.