Double throat nozzle capable of changing throat area and outlet area and method thereof

The invention discloses a double throat nozzle capable of changing a throat area and an outlet area and a method thereof. The double throat nozzle comprises a nozzle inlet, a nozzle outlet, and a nozzle front fixed segment, a nozzle converging segment, a concave cavity expansion segment and a concave cavity converging segment connected between the nozzle inlet and the nozzle outlet sequentially. The segments of a nozzle body profile are connected by hinges, and a hinge shaft a at the connecting site of the concave cavity expansion segment and the concave cavity converging segment is mounted ona slide rail; the paving direction of the slide rail is consistent to the axial direction of the nozzle; the hinge shaft a is connected to a power output end of a driving device A; and under the action of the driving device A, the hinge shaft a can slide along the slide rail. Therefore, the positions of the moving parts are changed by using the power driving device, so that the throat area and the outlet area of the nozz