Numerical simulation of a muzzle flow field involving chemical reactions based on gridless method

A gridless method for simulation of reactive flows involving moving boundaries was investigated based on the linear basis least-squares gridless method. The Euler equations of arbitrary Lagrangian-Eulerian form were employed as governing equations. The numerical flux and chemical sources were calculated by the multi-component HLLC ((Harten-Lax-van Leer-Contact) scheme and finite rate reaction model, respectively. An elevated restructuring technique of local cloud was adopted to deal with the moving boundaries. The front advance method of fictitious boundaries was used during the restructuring. The flow around the cylinder and the shock-induced combustion flow field were simulated to validate the accuracy firstly. The muzzle flow of a 12.7 mm machine gun was simulated. The computational shadowgraphs agree well with the experimental photographs, the density and pressure contours are in agreement with the results by the unstructured mesh method. The numerical results show the coupling and interaction progress in the initial muzzle flow field, the under-expanding jet of explosive gas and high-speed projectile clearly, and the temporal, spatial distribution characteristics of the muzzle flash are reappeared plainly.