Fuel/air mixture clouds have important research value in the process industry and military applications. Different from condensed explosions, blast height has a direct impact on the fuel cloud field and the detonation power field. In this paper, we establish numerical models of the detonation process of propylene-oxide (PO) clouds generated by the dispersion of 2kg fuel/air explosives at different blast heights. The process of fuel dispersion, detonation propagation and the distribution of the near-surface detonation power field are explored. Through theoretical analysis, we establish optimization models of the fuel/air explosive dispersion under different blast heights. The relationship between the proportional blast height, proportional distance and power field peaks are quantitatively revealed. The results show that the effect of cloud detonation on the ground power field is obvious. The optimal proportional blast height exists. When the cloud mass is 2kg, the optimum proportional blast height is 0.8m/kg1/3. At the optimum blast height, the overpressure effect of cloud detonation is the strongest (the peak overpressure is 2.19 MPa, and the action time is 1.77 ms), and the temperature range of cloud detonation is the largest (the peak temperature is 1462.16K, and the action time is 2.84 ms). Under the condition that the proportional blast height is less than or equal to the optimal proportional blast height, the power field peaks show N-shaped trends with the increase of the proportional distance. When the proportional blast height > proportional ignition radius > 0.8m/kg1/3,the peaks decrease with the increase of the proportional distance.

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