A Double-Bell Expansion-Deflection Nozzle

Abstract

The invention discloses a double-bell type expansion deflection nozzle. The double-bell type expansion deflection nozzle comprises an expansion deflection stopper cone, a nozzle converging section, adouble-bell type base expanding section and a double-bell type extension expanding section. The expansion deflection stopper cone is partly designed by a plurality of sections of circular curves, andthe expansion deflection stopper cone and an external wall surface form an annular throat, so that an air flow undergoes deflection flowing not parallel to the axial direction of an engine; an inflection point is formed between the double-bell type base expanding section and the double-bell type extension expanding section through a difference between a moulding surface and a nozzle axis chamfer,so that the air flow is separated at the inflection point when the double-bell type expansion deflection nozzle works at a low pressure drop ratio; the expansion deflection nozzle formed by the double-bell type base expanding section and the expansion deflection stopper cone is effectively utilized for altimetric compensation, so that relatively high push force performance is maintained; and at the high pressure drop ratio, the air flow expands along the double-bell type extension expanding section to a nozzle exit all the time, and the area of the nozzle exit is effectively utilized, so thatthe push force performance at the high pressure drop ratio is ensured.

Description

technical field [0001] The invention relates to the field of aerospace technology, and more specifically relates to a double-bell expansion deflection nozzle, which is mainly used in aero-engines with wide drop pressure ratio and high thrust performance requirements. Background technique [0002] With the development of aerospace technology, horizontal take-off and landing hypersonic vehicles have become the key development direction in recent years because of their advantages of instant strike and rapid penetration. As the core component of hypersonic vehicle power plant, the tail nozzle is also facing unprecedented It is a new technical challenge, its thrust characteristics and flow characteristics will directly affect the working efficiency and operation capability of the propulsion system. [0003] Unlike previous aero-engine exhaust nozzles, hypersonic engine exhaust nozzles need to maintain high thrust performance in an extremely wide drop pressure ratio, and due to th...

AI Technical Summary

Problems solved by technology

However, the above nozzles also have certain disadvantages. The double bell nozzle can only guarantee better thrust performance under the two design pressure ratios, but when working between the two design pressure ratios, there will be inevitable thrust Low point; the expansion deflection nozzle only has height compensation characteristics within a certain pressure ratio range, and when working under the condition of high overexpansion, the pressure at the bottom of the plug cone of the expansion deflection nozzle is too low, which will lead to a sharp deterioration in thrust performance; plug type The nozzle is also not widely used because of the large cooling area and the controversial compensation effect

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