Influences of the Cloud Shape of Fuel-Air Mixtures on the Overpressure Field

Abstract

This paper presents an experiment system in the open field, which comprises a charge structure (approximately 166.2 kg), a high-speed camera subsystem, and a pressure measurement subsystem. Through a series of experiments under the cylindrical clouds with different diameters, heights, and diameter-to-height ratios (D : H), the influences of various cloud shapes on the overpressure field were analyzed and discussed. Based on the experimental results, the overpressure field was divided into two zones: detonation wave zone and shock wave zone. It is found that the overpressure of shock waves at the same distance from the explosion center increased with the diameters, but the variations of heights had little impact on the overpressure. Therefore, the pancake-shaped cloud of fuel-air mixtures is the optimal shape for obtaining the wider overpressure field. Moreover, it is found that the overpressure field gets the maximum under the diameter-to-height ratios of 5.7 in the same distance within the studied range.

A Whole Explosive Dispersion Process Prediction Model for Fuel Clouds

“…Then, r = c and s r ¼ À P 1 for the outer wall of the shell, substituting them into Eq. (15). The expression of the velocity of the particle on inner wall variation with time is obtained as follows:…”

“…Wang et al used the commercial program (AUTODYN) and Gurney model to prove that the smaller ratio of center charge mass to fuel mass reduced the energy exchange between explosive products and air made more explosion energy convert into kinetic energy of particles [14]. According to the research of Bai et al [15], the peak overpressure variation corresponding to different directions is directly related to the cloud cross-section. The propagation of the shock wave was affected by the forms of dispersal cloud to a large extent.…”

Dispersal Characteristics Dependence on Mass Ratio for Explosively Driven Dry Powder Particle

“…Explosive dispersal of the granular materials is extensively applied in industrial security and military engineering [ 1 , 2 , 3 , 4 , 5 ]. Dry powder fire-extinguishing bombs explode and disperse the dry powder particles to form stable aerosols, serving for fire control and suppression [ 6 ].…”

Optimization of Ejection Characteristics for Twice-Detonating Device in Double-Event Fuel-Air Explosive with High Drop Velocity

“…In the modern military context, warheads equipped with double-event fuel-air explosives (DEFAEs) have great lethality, with the advantages of a large explosive area and high explosive strength [1][2][3][4][5][6]. A DEFAE typically follows two detonation processes to produce an explosive cloud [7][8][9][10][11][12]. The first detonation is used for dispersal of the fuel; the second one is for the timely initiation of the twice-detonating device (TDD) and detonation of the fuel-air mixture, bringing about an explosive cloud and causing shock-wave damage to the target.…”