Supersonic flow with pseudoshock formation by thermal addiction

The paper presents the results of a numerical study of the transition from supersonic to subsonic flow in a diffuser (with opening angles Θ = 10° and 90°) of a supersonic air inlet of a ramjet engine (ramjet), due to thermal effects. A description of flow characteristics (pressure, total pressure loss, Mach number) is given. Analysis of calculation results enables to find the relation between the heat addition and geometrical action on the flow in the channel, when the total pressure reductions feasibly coincide in the diffusor. In this case, the static pressure and Mach number at the combustion chamber entrance are also close to each other. It is shown that, when the diffusor with big opening angles is used for the above mentioned actions, the total pressure may rise by 2.7 ÷ 3 in the combustion chamber, which does not influence the air inlet performance and hence the automatic controllability of the total pressure ahead the combustion chamber entrance is provided.