A variable cycle engine

Abstract

The invention provides a variable-cycle engine, which comprises a first combustion chamber, a second combustion chamber and a third combustion chamber which are independent respectively, the first combustion chamber is a core combustion chamber, the second combustion chamber is located outside the high-pressure turbine, and the second The thermally expanded airflow combusted in the combustion chamber flows through the blade with the largest outer diameter at the rear end of the low-pressure turbine. The third combustion chamber is located outside the second combustion chamber and adopts a scramjet combustion chamber. The first combustion chamber, the second combustion chamber and the third combustion chamber A low-pressure evaporator is used to assist combustion, and the ratio of the engine turbine to the compressor thermodynamic cycle is adjusted by adjusting the oil supply of the first combustion chamber, the second combustion chamber and the third combustion chamber, so as to avoid the occurrence of engine surge and turn the turbine to work The temperature was originally uncontrollable, but it can be actively adjusted at any time, which greatly increases the ceiling and top speed of the engine. It can simultaneously integrate a turbofan engine and a scramjet engine into one machine while reducing parts and weight.

Description

technical field [0001] The invention relates to the technical field of axial flow engines, in particular to a variable cycle engine. Background technique [0002] Such as figure 1 As shown, in the design structure of the existing common axial-flow turbofan engine, the high-pressure airflow after combustion in the core combustion chamber 10 first drives the two-layer high-pressure turbine, and the high-pressure turbine is linked to the high-pressure compressor to rotate, and then passes through the low-pressure turbine, and the low-pressure turbine is linked. The low pressure fan turns, followed by the afterburner 20 . The principle is to expand the air entering the engine through fuel combustion in the core combustion chamber 10, part of the kinetic energy of the expanded airflow is directly the output force of the engine, and the other part of the kinetic energy drives the turbine, and the turbine drives the compressor and the fan, so that the external air continuously flo...

AI Technical Summary

Problems solved by technology

[0003] The existing engines have the following problems: 1. If the engine output power needs to be increased, refueling can only be carried out in the core combustion chamber 10 and the afterburner 20, and too much refueling in the core combustion chamber 10 will cause the temperature of the combustion chamber to increase significantly. Raise, the turbine material is unbearable

2. Due to the fixed matching relationship between the turbine and the compressor, the engine cannot adapt to the huge wind pressure changes at high and low speeds during flight, and engine surge is unavoidable

3. Refueling in the afterburner 20 will greatly reduce the thermal-dynamic conversion ratio of fuel (large fuel consumption), slow down the airflow blockage in the turbine chamber, cause the temperature of the turbine to continue to rise, and slow down the airflow in the turbine chamber to reduce the output power of the turbine, which in turn leads to The reduction of compressor power and fan power directly leads to the decrease of the overall air flow of the engine and the increase of wind resistance

In short, the existing turbofan engine design has small potential for engine power adjustment, high fuel consumption and unstable performance, which is not suitable for changing flight environments

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