Pneumatic and structural feature considered three-dimensional geometric structure of fan blade of aircraft engine

Abstract

The invention discloses a pneumatic and structural feature considered three-dimensional geometric structure of a large fan connotative blade of a civil aircraft engine. The rear section of a blade profile at the root part of the large fan which is designed traditionally has a larger bent corner, a smaller acute angle is formed by a trailing edge suction surface and a hub, low-energy gas is accumulated in the acute-angle area, the flow loss is great, and the smaller acute angle between the suction surface and the hub is not beneficial to the structure modeling of the root stretching section of the blade. According to the invention, the change of an outlet metal corner of an element blade profile of the large fan connotative blade (which is the part within 20% of a blade height of the large fan blade) along the blade height is mainly optimized and a distribution curve of the outlet metal corner of a connotative blade and a projection curve of a trailing edge line in a plane vertical to the axial direction are fit. Through the verification of three-dimensional CFD (Computational Fluid Dynamics), the pneumatic and structural feature considered three-dimensional geometric structure disclosed by the invention has the advantages that the flow separation in the acute-angle area formed by the trailing edge suction surface of the fan and the hub can be effectively reduced, the fan connotative efficiency can be increased, a good entrance condition is provided for a pressure boosting grade, and the blade at the root part and the hub are relatively almost vertical, so that convenience is provided for the installation of the blade on a wheel disc.

Description

technical field [0001] The invention relates to a three-dimensional geometric structure of connotative blades of a large fan of a civil aeroengine taking into account both aerodynamic and structural features, and belongs to the technical field of impellers of turbomachinery axial flow compressors. Background technique [0002] In the large fan of a civil aeroengine, the flow parameters change drastically along the radial direction due to the relatively small hub. The traditional design idea is to adopt the law of power distribution along the blade height, thinking that this can minimize the radial mixing of the flow and reduce the flow loss. Due to the large difference in the root tip tangential velocity of large fans, in order to ensure that the power from the root to the tip of the rim is equal, it is necessary to have a large twist of the basic element blade shape of the internal blade of the fan, so the suction surface of the traditional fan internal blade trailing edge ...

AI Technical Summary

Problems solved by technology

However, studies have shown that the design of equal power distribution cannot minimize the radial mixing of the flow. In terms of aerodynamics, low-energy gas accumulates in the corner area formed by the suction surface of the trailing edge and the hub, and the loss of flow separation is very large. At the same time, it also makes the inner outlet of the fan The high Mach number increases the difficulty and risk of supercharging stage design; in terms of structure, the small angle between the suction surface and the hub is also not conducive to the structural shape of the root section, which makes it difficult to install the blade on the wheel , it is possible to generate excessive stress in the root section

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