The flowfield and performance analyses of turbine-based combined cycle inlet mode transition at critical/subcritical conditions

The fluid dynamics and performance analyses of steady and continuous combined cycle inlet mode transition at critical/subcritical conditions were investigated through wind tunnel tests and three dimensional unsteady numerical simulations. When the inlet operated at critical condition, the terminal shock was unsteady and oscillated in the frequency between 40 Hz and 60 Hz around the shoulder of inlet and the downstream of cowl leading edge. In critical inlet mode transition the performance parameters of diffuser exit varied with positions of terminal shock. When the inlet operated at subcritical condition, terminal shock was steady at the upstream of cowl leading edge. The continuous mode transition test results reveal that the shock can be steady at subcritical condition. Considering the shock stability and performance parameters at the diffuser exit, subcritical inlet mode transition is better than critical condition for combined cycle inlet investigated in this paper.