RU94025919A - Double-flow turbojet engine with heat exchanger - Google Patents

Abstract

FIELD: heavy transport and passenger aircraft. SUBSTANCE: air pressure ratio in modern turbojet engines reaches 27-30. Further increase of air pressure ratio enhances economical efficiency of engine to insignificant level but specific thrust reduces considerably due to rise of temperature after compressor. Provision is made for intermediate cooling of air in compressor. As soon as air pressure ratio $$$ reaches approximately 10, air from compressor is fed to heat exchanger where it is cooled with cold air forced by second-loop fan. Heat is transferred from first-loop compressor to second-loop air heating it and increasing rate of flow, thus increasing the engine thrust. After heat exchanger cooled air enters the high-pressure compressor. Compression work in high-pressure compressor is reduced by 1/3 due to drop of temperature, thus increasing the free energy by two times. The bypass ratio "m" at $$$=1.42 of fan increases from 5 to 10, thus increasing the engine thrust by two times. Heat exchanger consists of segments twisted by Archimedean spiral which makes it possible to ensure even pitch of passages by engine diameter. Segments are made from light metal, for example, aluminium. Compressed air from compressor enters inner passages whose passage areas may be small. Outer passages have large areas and are provided with outer fins to ensure required heat exchange surface. Segments are supported by rests to ensure required rigidity and avoid vibrations. EFFECT: enhanced economical efficiency and specific power of engine.

Claims (1)

The dual-circuit turbojet engine with heat exchanger is designed for heavy transport and passenger aircraft. To increase the efficiency of the engine and its specific power, intermediate air cooling was introduced into the compressor. Upon reaching a degree of pressure increase (Pc) of the order of 10, air from the compressor enters the heat exchanger, where it is cooled by cold air pumped by a secondary fan. The heat that is transferred from the compressor of the primary circuit to the air of the secondary circuit heats it and increases the flow rate, which increases the thrust of the engine. The cooled air after the heat exchanger enters the high-pressure compressor. The compression work in the high-pressure compressor by reducing air temperature decreases by 1/3, which means that free energy is doubled. The bypass ratio m with П _к = 1.42 fans increases from 5 to 10. This allows you to double the engine thrust. The heat exchanger is made of segments that are twisted in a spiral of Archimedes, which allows for uniform channel pitch along the diameter of the engine. Segments are made of light metal, for example, aluminum. Compressed air from the compressor enters the internal channels, the passage sections of which may be small. The outer channels have large passage sections and external fins, which provides the necessary heat transfer area. To provide the necessary rigidity and eliminate vibrations, the segments are supported by stops.