Experimental study on the explosion characteristic and flame propagation of methanol spray at different injection pressures

The risk of methanol spray explosion increased under negative pressure. And the explosion characteristics and flame propagation of methanol spray at different injection pressures under negative pressure have been further investigated in this paper. Experiments were carried out by varying the injection pressure (13-21 bar) to study effects of different turbulence intensities on spray explosion. The effect of different concentrations (198-514.8 g/ m3) and initial temperatures (303.15-323.15 K) on the explosion of methanol sprays (308.15 K) was also explored. At different injection pressures, decreasing concentrations and increasing initial temperatures promoted a reduction of particle size linearly. The effect of initial turbulence on the combustion and explosion regions was not remarkable. However, the increasing injection pressures facilitated the pmax, (dp/dt)max, and Tmax of methanol spray. The excessive methanol concentration inhibited the explosion characteristics. The increase of initial temperature significantly increased the risk of spray explosion. However, when the initial temperature was above 313.15 K, the particle size of methanol spray was less than 10 mu m. The expansion rate of the combustion region remained stable. And the spray explosion was close to the vapor-phase methanol explosion.