Numerical modeling of detonation combustion of hydrogen-air mixtures in a convergent-divergent nozzle

Starting of an axisymmetric convergent-divergent nozzle in a hypersonic flow

“…Flow past the model with a detached shock is visible in the shadowgraph Fig. 5b, which indicates the formation of a subsonic flow in the convergent channel section and was numerically established in [5].…”

“…As distinct from [5], in this study, as the nozzle is thrown in a supersonic flow, the gas within the channel starts to be entrained in the motion simultaneously at the nozzle entry and exit, as a result of the breakdown of flow parameter discontinuities in these sections. A successful starting, without the formation of an inverse flow in the divergent nozzle section, occurs at M 0 = 6 ( Fig.…”

“…At M 0 = 6 the interaction between the outflowing gas and the external flow ensures in the calculations the starting of a nozzle with an extended supersonic region (R 2 = 5, x 2 = 14) without return flow (see [5]). At M 0 = 5 the nozzle with the diffuser shape considered cannot be started.…”

“…In the first set pylon 5 was fixed in position II until the flow from nozzle 2 arrived. At the starting of the setup the freestream Mach number rapidly increases to M 0 = 6 which corresponds to nozzle acceleration from the state of rest (see [5]). Flow past the model with a detached shock is visible in the shadowgraph Fig.…”

“…In [4] the starting in which a supersonic flow is also realized in the convergent section of a convergent-divergent nozzle, that is, in the diffuser. The starting of this type can become necessary in connection, for example, with the solution of the problem of stabilizing detonation combustion of a hydrogen-air mixture entering in the nozzle at a hypersonic velocity [5].…”