Pneumatic design method for separation type exhaust jet pipe of high bypass ratio engine

Abstract

Pneumatic design method for separation type exhaust jet pipe of high bypass ratio engine, which is characterized in that: the method adopts parametrization design, a straight line segment form composes a pneumatic shape of the jet pipe, circular arcs are used for smoothly connecting among the straight line segments. A concrete flow is that: step 1, defining an initial parameter of the pneumatic design of the jet pipe, and assigning; step 2, solving the other parameter according with a geometric relation of the jet pipe shape and establishing a mathematics model; step 3, generating the jet pipe shape controlled by the step 1 and the step 2; step 4, examining the pneumatic shape whether reaching to a required pneumatic performance - if yes, finishing the design flow; if no, returning to thestep 1 and restarting the flow. The design method can design an inner-outer bypass jet-pipe flow scheme rapidly, check the scheme whether practicably reduce the design period obviously, and ensure a simple processing method.

Description

technical field [0001] The invention belongs to the field of aerodynamic design of a split exhaust nozzle of a large bypass ratio engine. Background technique [0002] Document A numerical investigation into the nozzle flow of high by-pass ratioturbofans[92-GT-10, H.ZIMMERMANN] proposed the idea of ​​using some parameters to represent the shape of the nozzle, but its connotation nozzle is not a plug nozzle, A mathematical model for establishing the aerodynamic shape of the inner and outer nozzles using these variables is not given in this paper. [0003] H. ZIMMERMANN carefully discussed the aerodynamic shape design of the external nozzle, and believed that the design principle of the external nozzle is to obtain as much expansion as possible in the nozzle, because the momentum item in the thrust composition can bring a greater impact than the pressure item. thrust, and think figure 1 The configuration "C" in the configuration "C" will have a local pressure decay area on t...

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Problems solved by technology

But we believe that the reason for the high performance of configuration "C" is that the velocity field at the outlet of the outer culvert is more uniform than that of other structures (you can compare the other four structures), and the uniform velocity field is the same as the uniform pressure field , uniform temperature field, and uniform outlet flow field will lead to greater thrust

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