Experiment on wall temperature of an air-breathing pulse detonation engine

To explore the trends of wall temperature variation with time and detonation frequency as well as wall temperature distribution along the tube outer wall, experimental study on wall temperature of an air-breathing pulse detonation engine was performed. This is a valveless air breathing pulse detonation engine with 68mm in diameter and 2000 mm in length. The experiment was conducted with gasoline /air mixture at frequency of 10Hz, 20Hz, 40Hz, respectively. The wall temperature was measured by a thermal image camera. The results indicate that: (1) the increasing rate of outer wall temperature decreases as time increasing on the same frequency; (2) at heat balance point, outer wall temperature is higher with higher frequency; at frequency of 10Hz, 20Hz, 40Hz, outer wall temperatures are over 726°C, 1011.5°C, 1159.5°C, respectively at the heat balance point; (3) before heat balance, increasing rare of wall temperature increases as frequency increasing; increasing rate of wall temperature is proportional to frequency approximately; (4) along the direction of forming detonation, outer wall temperature increases by degrees; at the detonation point temperature is highest; from detonation point to engine exit, outer wall temperature decreases by degrees; (5) on each frequency, the highest temperature area is the same, about 1350 mm from the ignition location; (6) at the same axial location, outer wall temperature increases as frequency increasing. The increasing amplitude of the temperature decreases as frequency increasing.