Initiation of detonation in a tube with parabolic contraction and conic expansion

The use of the profiling of axisymmetric tube walls in the shape of parabolic contraction and conic expansion for initiating the detonation by means of a relatively weak shock wave is examined. For simulating the propane-air mixture, researchers found the parabolic-contraction shape and selected the conic-expansion parameters providing the initiation of detonation for the Mach number of an original shock wave equal to 2.65. It is assumed that the motion in the tube occurs as a result of the ISW propagation along it with the set Mach number in the initial moment at the tube input and constant parameters behind its front. The flow is described within the framework of the model of an ideal compressed multicomponent reacting gas mixture in the axisymmetric and three-dimensional unsteady formulations.