Numerical simulation of fuel dispersal into cloud and its combustion and explosion with smoothed discrete particle hydrodynamics

Abstract

A fuel air cloud is formed under the driving force of the explosive detonation and then it’s ignited to explosion to attack the target. The existing numerical simulations are mainly limited to the fuel dispersal processes which are all based on mesh methods. The fuel particles in the air cloud are difficult to traced. Otherwise, the computing process is complex and could not be solved by the exiting methods for the chemical reaction and the forming and propagation of shock waves are both involved in the fuel combustion and explosion. Smoothed discrete particle hydrodynamics (SDPH), as a new method to solve the gas-particle two-phase flow, has been successfully used to simulate the aeolian sand transport, heat transfer and evaporation. Based on the previous work, the Jones-Wilkins-Lee (JWL) function is imported to describe the explosive detonation to expansion and it is solved by finite volume method. The fuel drops dispersed by explosion are traced by the improved smoothed particle hydrodynamics. The drop evaporation model and the EBU-Arrhenius combustion model for gas high-speed combustion are introduced to describe the combustion and detonation of fuel drops. Then we build a new SDPH method to simulate the warhead initiation, fuel dispersal, and the fuel second explosion. Firstly, we design a test that is the dispersal of circular fuel drops drove by explosive detonation to validate our new method. The changing of the explosive detonation pressure and the velocity fields of explosive and particles are analyzed and they are consistent with the theory. And then, the forming and developing of FAE cloud are simulated. Through comparing with the experiments, the shapes of the cloud by the two methods coincide with each other. The effects of different initiations on the cloud forming are also analyzed. Finally, based on the cloud group forming, the evaporation and combustion models are introduced to study the combustion and explosion of FAE. We obtain the velocity field and the distribution of combustion product. The result indicates that the fuel dispersal into cloud and its explosion can be simulated better with the mathematical model and computational method built in this paper. This finding supplies a more effective numerical method for the design and research on this type of weapon equipments.