Dual-pressure jet engine and device for work done by compressed air thereof

A dual-pressure jet engine, comprising a device for work done by compressed air, and a main casing, the device comprising:

• an inner casing and a main shaft,
• wherein the main shaft extends in the inner casing along an axial direction of the inner casing, wherein an air intake compressor and a screw gas compressor are successively provided on the main shaft along a gas flowing direction, the inner casing is provided with an inner duct for introducing air into the air intake compressor at a front end of the air intake compressor, a first compressed air storage chamber for cooperating with the air intake compressor is arranged between the air intake compressor and the screw gas compressor, the air intake compressor is configured to pressurize the air, the first compressed air chamber communicates with the screw gas compressor, an air intake end of the screw gas compressor is provided with a fuel injection mechanism for injecting fuel inside the screw gas compressor, an air outlet end of the screw gas compressor is provided with two second compressed air storage chambers, the screw gas compressor is configured to pressurize air, the two second compressed air storage chambers communicate with a combustion chamber, the combustion chamber is configured to be injected with fuel, and an ignition mechanism for detonating a mixture of the fuel and the air is arranged in the combustion chamber;
• wherein the main casing is sleeved outside the device for work done by compressed air, two ends of the main casing are opened so as to form an inlet port and an outlet port, individually;
• a main air intake fan is arranged inside the inlet port of the main casing and communicates with the inner duct, and the outlet port of the main casing is provided with a main pushing chamber;
• the main pushing chamber communicates with the combustion chamber, the main shaft extends into the main pushing chamber and is coaxially sleeved with a high pressure turbine, the high pressure turbine directly faces to an air outlet of the combustion chamber, an outer duct is arranged between the main casing and the device for work done by compressed air, the outer duct and the inner duct communicate with the inlet port in parallel, and two airway turbofans for pressurizing the air in the outer duct are arranged between the high pressure turbine and the main pushing chamber.