A Design Method for Inlet Split Flow and Stability Expansion Applicable to Counter-rotating Lift Fans

Abstract

The invention discloses a design method for diverting and expanding the stability of an inlet of a counter-rotating lift fan. The spline curve interpolation method is used to reconstruct the profile of the casing end wall of the fan inlet section, and the reconstructed casing end is a curved cone. The taper angle is smoothly transitioned from the inlet of the lift device to the inlet guide vane; the circumferential shunting groove is connected and designed between the leading edge of the inlet guide vane and the position near the leading edge of the first stage rotor, and the area of ​​the through groove decreases from the inlet to the outlet. The invention changes the traditional layout mode of self-circulation expansion and stabilization of air bleed from the rear stage to the front stage, thereby fundamentally reducing the performance loss of the rear stage; the use of the inlet curved tapered design suppresses the inlet guide vane caused by the shunting of the inlet pipeline. The flow of the blade tip deteriorates; the advantage of the lower pressure difference between the front end of the inlet guide vane and the leading edge of the rotor is used, so that the inlet flow consumed by the shunt pipeline is very limited, so the harmful offset effect of the performance curve of the whole machine is weak; It is effective for lift fans with various speed conditions and various load levels.

Description

technical field [0001] The invention relates to the technical field of counter-rotating lift fans for aviation, in particular to a design method for inlet diversion and stability expansion of counter-rotating lift fans, and is especially suitable for weakening the separation of first-stage rotor blade tips of counter-rotating lift fans and expanding counter-rotating lift devices The case of stability margins. Background technique [0002] The counter-rotating lift propulsion fan plays an important role as a power source during the take-off and landing of short vertical take-off and landing aircraft, and its stability determines the safety of its landing process. Due to the harsh operating environment of short vertical take-off and landing aircraft, and the limited flow stabilization section at the entrance of the lift propulsion system, the instability problem faced by the first-stage rotor blade tip is more prominent when it is distorted or even flows smoothly. Therefore, ...

AI Technical Summary

Problems solved by technology

Essentially, the driving force of the fluid in the self-circulation communication tank still comes from the work of the impeller, which will inevitably lead to a decrease in the theoretical work downstream of the impeller.

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