Effect of Temperatures on Flame Propagation of Diethyl Ether Spray Explosion

The study aims to identify the flame propagation in the diethyl ether (DEE) spray explosion through mathematical analysis by processing the gray-level histogram of the flame images. Different ambient and material temperatures’ effect on flame propagation and structure was investigated using a high-speed camera in a 20-L explosion vessel. The results showed that the overall duration could be divided into combustion and deflagration processes. With the ambient temperature increased, the combustion duration showed a trend of first decreasing, then increasing, and then decreasing again. The combustion zone first increased and then decreased. The explosion duration showed an overall decreasing trend. The explosion duration was longer than the combustion duration, ranging from 152.75 to 307 ms. The overall combustion and explosion duration trend was consistent with the explosion duration. When the ambient temperature was 308.15 K, the combustion duration reached its minimum value of 13.25 ms, and the equivalent radius of the combustion zone reached its maximum value of 52.89 mm. With the increase in material temperature, both the combustion and explosion durations showed a trend of first decreasing and then increasing, with combustion durations ranging from 12.42 to 16.25 ms and explosion durations ranging from 106 to 117.5 ms, respectively. When the material temperature was 308.15 K, the combustion zone expansion rate reached its maximum value of 10.20 m/s, and the explosion zone expansion rate reached its maximum value of 13.36 m/s. The effect of ambient temperature on the development of combustion zone is greater than that of material temperature, which is mainly reflected in the obvious change of equivalent radius.