Investigation of a Movable Slot-Plate Control Method for Hypersonic Inlet Unstart Caused by Downstream Mass-Flow Choking

Violent oscillation caused by unstart in a hypersonic inlet will always bring fatal damages to the flight control and structural safety of the vehicle. A new control method for the hypersonic inlet unstart caused by downstream mass-flow choking based on a movable slotplate is brought forward and investigated by computational method. First, the start and unstart flows of the two-dimensional rectangular hypersonic inlet are studied at a freestream Mach number of 4.92. The results show that the captured mass flow rate is 3.005kg/s at the started mode and the dominant frequency of oscillations is approximately 351Hz at the unstarted mode with TR=58%.Then, the movable slot-plate starts to open to let air flow spill, and when the mass flow rate of spilled reaches 1.447kg/s, the oscillation of the unstard flow vanishes. However the slot-plate has no effect on improving the inlet restart capability.