Double-S-bend convergent-divergent spray pipe with infrared suppression measure

Abstract

The invention discloses a double-S-bend convergent-divergent spray pipe with an infrared suppression measure, and belongs to the field of aero-engines. The double-S-bend convergent-divergent spray pipe comprises an engine outer duct, an engine mixer, an engine inner duct, a cooling channel, a spray pipe contraction section, a spray pipe expansion section and a spray pipe throat part, wherein the cooling channel is located on the periphery of a leeward area of the S-bend spray pipe and is composed of a cooling channel wall covering the leeward area of the S-bend spray pipe and an S-bend spray pipe wall; an opening is formed in the starting end of the cooling channel, and the other sides are connected with the S-bend spray pipe wall through the edge of the cooling channel wall to form a closed structure and communicate with the interior of the S-bend spray pipe through bypass air inlet holes and cooling outlets; and the plurality of bypass air inlet holes are evenly distributed in the starting end of the cooling channel in the circumferential direction, and the cooling outlets are located in the tail end of the cooling channel and communicate with the S-bend spray pipe through a plurality of cooling air outlet holes. The temperature of the wall surface of the spray pipe is reduced by airflow in the cooling channel, so that the infrared radiation characteristic of the spray pipe is reduced; and flow separation of the leeward area of the double-S-bend spray pipe is improved through airflow exhausted by cooling holes, so that the thrust of the spray pipe is improved.

Description

technical field [0001] The invention belongs to the field of aero-engines, and in particular relates to a double-S-curved retractable nozzle with infrared suppression measures. Background technique [0002] The S-curved nozzle structure can shield the hot walls such as turbine blades and central cones in the aero-engine, thereby reducing the infrared radiation intensity of the solid wall received by the detector; in addition, the S-curved pipe and the binary or special-shaped outlet also intensify the airflow The mixing effect of the gas reduces the range of the high temperature area in the plume area, thereby reducing the infrared radiation intensity of the gas. In terms of radar scattering, the S-curved nozzle structure reduces the radar echo intensity received by the monostatic radar. It is this structural feature that enables the S-curved nozzle to reduce the forward and backward infrared and radar features of the aircraft, and has been widely concerned in the developme...

AI Technical Summary

Problems solved by technology

For example, CN107229798A discloses "A Design Method for Double S-curved Nozzles", which proposes a design process for S-curved pipes, which can improve the generation efficiency of the pipe profiles of double S-curved nozzles. The influence of the wall temperature of the nozzle is not considered

CN208310917U discloses "a transition section structure that solves the matching problem between the S-curved nozzle and the turbofan engine", proposes a structure to improve the matching of the engine, analyzes the shape of the connection between the nozzle and the engine, and passes the proposed A contracted connection structure to improve the matching between the S-bend nozzle and the engine, but the infrared stealth performance of the S-bend nozzle was not analyzed and the cooling of the wall was not considered

[0004] When the double S-bend nozzle is used in a small bypass ratio turbine engine, the high-temperature gas at the outlet of the engine turbine breaks through the cold flow from the outer bypass and will impact the curved wall of the double S-bend nozzle, causing the temperature of the curved part to increase and the local thermal stress to increase , and even the separation of the airflow will cause the aerodynamic performance to decline, which will have an adverse effect on the structure, aerodynamics and infrared stealth performance, thus affecting the performance of the aircraft

Therefore, there is an urgent need for a technical solution to solve the problem of uneven temperature and pressure distribution at the bend in the double S-bend nozzle

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