Variable cycle engine

Abstract

The invention provides a variable cycle engine. The engine comprises a first combustion chamber, a second combustion chamber and a third combustion chamber which are independent, wherein the first combustion chamber is a core combustion chamber, the second combustion chamber is positioned on an outer side of a high-pressure turbine, thermal expansion airflow combusted in the second combustion chamber flows through a blade with the largest outer diameter at a rear end of the low-pressure turbine, the third combustion chamber is positioned outside the second combustion chamber, a scramjet combustion chamber is adopted, the first combustion chamber, the second combustion chamber and the third combustion chamber adopt low-pressure evaporators for auxiliary combustion, a thermodynamic cycle ratio of an engine turbine to a compressor is adjusted by adjusting oil supply of the first combustion chamber, the second combustion chamber and the third combustion chamber, engine surge is avoided, the working temperature of the turbine can be actively adjusted and controlled at any time instead of being originally uncontrollable, and the engine rise limit and the highest speed are greatly increased. The engine is advantaged in that the turbofan engine and the scramjet engine can be integrated into a whole at the same time under the condition that parts and the weight are reduced.

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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