关键词: 爆轰;聚心火焰+;激波;数值仿真

Abstract: Based on two-dimensional axisymmetric Euler equations,coupled with chemical reactions,the phenomena of implosion combustion were numerically studied by using wave propagation algorithm with Superbee limiter in the cylindrical combustor for two types of boundaries.The wave structure and flame distortion in DDT were discussed according to the calculated results.In the cylindrical combustor with two open ends the simulations show that shock induced by combustion reflecting back and forth from walls and the axis of the combustor gives rise to multiple shock-flame interactions.The shock-flame interactions,through the Richtmyer-Meshkov instability,enhance the flame combustion, but fail to transit to detonation.In the case of one closed and another open end the calculated results show that reflected waves from closed end frequently penetrate the flame,leading to continuous flame excitation and forms turbulence. Finally,DDT occurs.The calculated parameters of steady detonation wave front are compared with those of CJ theory,and the good agreement can be obtained.Simultaneously,repeated shock-flame interactions cause instability and distortion of the flame,and then form the shape of symmetrical collapsing flame front in the first boundary and asymmetrical collapsing flame front in the latter boundary.

Key words: Detonation;Implosion flame+;Shock wave;Numerical simulation