Bypass casing for engine

Abstract

The invention discloses a bypass casing for an engine and belongs to the field of design of engine casings. The bypass casing comprises an outer casing, an inner casing, junction boxes and a support; a core engine unit body (6) of the engine is sleeved with the inner casing (2); the inner casing (2) is sleeved with the outer casing (1); a flow channel is formed between the outer casing (1) and the inner casing (2); multiple junction boxes are arranged in the flow channel between the outer casing (1) and the inner casing (2) so as to lead out pipelines; the support and the core engine unit body are separately mounted through bolts; and the other end of the support adopts the arc-shaped structure and is glidingly connected with the back section of the inner casing. The outer casing forms an upper wall surface of the bypass flow channel, the inner casing replaces the core engine unit body to form the lower wall surface of the bypass flow channel, the flow channel formed by the outer casing and the inner casing effectively reduces the total pressure loss of the bypass, the total pressure recovery coefficient is increased, the vibration effects caused by air flows on the engine structure and accessories are reduced, and the structural reliability is improved.

Description

technical field [0001] The invention belongs to the field of engine casing design, and in particular relates to an engine external casing. Background technique [0002] The external casing is an important structural unit for the aviation turbofan engine to form external flow passages and realize structural integrity and engine functions. The external casing is located behind the intermediate casing, before the turbine rear casing, and surrounds the outside of the core unit. The outer casing usually contains external accessories such as actuators, controllers, bleed pipes, lubricating oil supply / return pipes, cables, etc. These external accessories are arranged according to the functional requirements of the engine, which is diverse, disordered and scattered characteristics such as sex. [0003] Existing external engine casings are usually single-layer wall structures, which mainly play the role of forming external flow channels. This type of external accessories directly e...

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Problems solved by technology

[0006] (3) In terms of cost: the external casing is usually a thin-walled sheet metal structure, the process is simple, and there is no cost advantage

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