Weak Shock Waves in Spherically Symmetric Reactors during Propane Oxidation: Experimental Evidence of the Presence of a Saddle-Type Special Point at the Center of the Reactor

Abstract The phase space of low-temperature propane oxidation in a spherical reactor has been investigated in terms of the presence of special points by registering light emission pulses resulting from the generation of weak shock waves in the near-surface layer of the reactor. The phenomenon is explained using the results of the well-known self-similar method to assert that a saddle point forms at the center of the reactor due to the convergence of the weak shock wave towards the reactor’s center. The property of the weak shock wave to reflect off surfaces, as well as from the saddle point, leads to a situation where both the periphery and the center of the reactor reflect the weak shock wave. Under these conditions, closed trajectories typically exist, onto which the trajectory of the shock wave wraps. As a result, it becomes possible to register the radiation of the shock wave occurring in the combustible mixture. Justification is provided for the possibility of experimentally registering weak shock waves in the reactor.