Journal of Shanghai University(Natural Science Edition) ›› 2020, Vol. 26 ›› Issue (5): 802-815.doi: 10.12066/j.issn.1007-2861.2094

• Research Articles • Previous Articles     Next Articles

Interfacial instability and particle dispersion of explosion-driven fuel cloud

SHEN Yang, DING Jue(), WENG Peifen   

  1. Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China
  • Received:2018-09-18 Online:2020-10-30 Published:2020-11-06
  • Contact: DING Jue E-mail:dingjue_lu@shu.edu.cn

Abstract:

In industrial explosion disaster area and the military area, the unsteady two- phase combustion detonation of the fuel cloud composed of gas and fuel particles can have a destructive effect on the surrounding medium, which is closely related to fuel motion characteristics and mass spatial distribution. In this paper, a two-dimensional gas-liquid (two-phase) flow model is established. Based on the finite volume method and the two-order accuracy monotonic upwind scheme for conservation laws (MUSCL) difference scheme, the numerical study on propagation of the shock waves in a two-phase medium, instability evolution of the fuel cloud interface, the mechanism of shock induced vortices and the initial motion of fuel cloud are conducted based on $n$-heptanes as the fuel. The research results show that the interaction between shock wave and fuel is a transfer process of momentum and energy. When the shock wave sweeps through the two-phase medium, the pressure attenuates and the relation with the proportional distance satisfies the power law. Moreover, the reflected wave and refraction wave are generated in the cloud and the wave front in the gas-liquid medium is bent. The liquid fuel obtains the same propagation direction of wave. For the initial particle size 60 $\mu $m, the fuel cloud will increase up to 22.8 m/s during the period of 112 μs. In the meantime, when the shock wave acts on the fuel cloud, then the flow field at the gas-liquid interface is disturbed. During the wave passing around the fuel cloud, large-scale vortices will be generated around the outer edge of cloud, which enhances the turbulence intensity of the original undisturbed flow field. Furthermore, the vorticity is induced by the density and pressure gradient of the flow field near the interface, and the development of Richtmyer-Meshkov instability (RMI) makes the interface generate a series of small-scale vortices. Large and small-scale vortices promote the development of turbulence, which also enhances the movement of fuel cloud and the dispersion of particles. It provides important conditions for the expansion of the cloud and subsequent two-phase detonation.

Key words: explosion-driven, shock wave, fuel cloud, shock-induced vortex, particle dispersion

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