High Resolution Numerical Simulation Of Two Phase Hybrid Detonation In Gas-solid Flow

In the process of industrial production,if there is flammable gas and combustible dust in the air at the same time,the two-phase hybrid explosion will occur when there is an ignition source with enough energy.Due to the existence of flammable gas,two-phase hybrid explosion is easier to occur and is generally at higher risk compared with dust explosion.Because of the existence of dust,the two-phase hybrid explosion is more powerful than gas explosion,which is more harmful.The study of two-phase hybrid explosion is of great significance for the protection of industrial safety.Because of complexity of the two-phase hybrid explosion involved,there are many difficulties in theoretical research.There are also many difficulties in experimental study,for example uniform particle size and distribution is difficult to control,which result in that today experimental study concentrated in the explosion characteristic parameters,study on detonation wave propagation law and coupling mechanism between shock wave and chemical reaction is relatively insufficient.This paper focusses on the detonation problem in the two-phase hybrid explosion,and carried out numerical research.In the two-phase hybrid detonation,a multi-components two-phase reaction dynamics model is established in order to describe homogeneous chemical reaction and two-phase chemical reaction coupling problem.Because of the strong discontinuities in detonation flow field,the traditional high accuracy calculation method for solving discontinuous problems will result in numerical oscillation.In order to solve this problem,a high resolution calculation method based on WENO(weighted essentially non oscillatory)schemes is developed to simulate two-phase hybrid detonation.The high resolution numerical simulation of the two-phase mixing detonation wave propagation process is realized.The main work of this paper is as follows:(1)Based on the specific characteristics of gas detonation,the control equations of gas phase detonation neglect viscous diffusion and heat conduction are established.By simplifying the governing equations,the analytical solution of one dimensional steady state ZND detonation wave is derived.Considering discontinuous problems in gaseous detonation of,a high resolution WENO finite difference method is constructed based on the local characteristic decomposition.(2)Traditional WENO scheme is of low efficiency when simulation detonation which exist multi-scale characteristic.An adaptive mesh refinement method based on high resolution WENO scheme is developed to solve the low efficiency problems.This method make improvement in following respects of the traditional adaptive mesh refinement method: establishes the grid data structure based on the index table,propose an adaptive refinement criterion based on pressure and reaction progress,develop high precision data prolongation method,using the Hilbert space filling curve algorithm realized the dynamic partition of the computation domain.(3)Based on adaptive mesh refinement method mention above,dynamic load balancing parallel adaptive mesh refinement program is developed which is of high resolution.The high efficiency and high precision numerical simulation for shock wave and detonation problem are realized.The computational accuracy of the method is tested by constructing human solution.The efficiency and accuracy of the method are tested by simulating some classical shock problems.The method is used to simulate gas phase detonatin problem,verified the method is reliability in simulating gas phase detonation.(4)A multi-components two-phase reaction dynamics model is established in order to describe the homogeneous chemical reaction and two-phase chemical reaction coupling problem.The multi-component gas phase state equation is established,based on the assumption of pressure equilibrium,the solid state equation is established,Mass,momentum and energy exchange model between the two phase is given,the above state equation and exchange model make the two-phase hybrid detonation model to a closed model.The local characteristic decomposition method of multi-component equations is realized,and the finite difference method based on the WENO scheme is constructed.(5)A high precision parallel computing program for the two-phase hybrid detonation problem is developed.A theoretical analysis of the aluminum dust two-phase reaction model is carried out.The propagation process of aluminum dust/ air two-phase detonation wave in different conditions was simulated.The influence of pipe width and aluminum particle concentration on detonation wave propagation was studied.The propagation process of aluminum dust/acetylene/air two-phase hybrid detonation wave in different conditions was simulated,and the effect of particle size on detonation wave propagation characteristics is studied.The propagation process of coal dust/methane/air two-phase hybrid detonation wave in different conditions was simulated,and the effect of methane and coal dust concentration on detonation wave propagation characteristics is studied.