Ultralow-noise concave-convex bionic subway tunnel axial-flow fan movable blade

Abstract

The invention discloses a ultralow-noise concave-convex bionic subway tunnel axial-flow fan movable blade. The blade comprises a blade body, and a blade tip and a blade root positioned at the head and the tail of the blade body; multiple sections are divided in the radius direction from the blade root to the blade tip; gravity center accumulation lines of all the sections are arranged in a compounding manner of sweepback and sweepforward; the blade is reversely C-shaped in the airflow direction; a flange plate type blade handle is arranged at the blade root; and a streamlined reinforcing body is arranged between the blade body and the flange plate type blade handle. After a subway / tunnel axial-flow fan adopts a bionic reverse C-shaped design, the operation efficiency of the blade is greatly improved compared with a pure sweepforward mode, meanwhile, the eddy current noise of the blade is reduced at the same time, the safety and the reliability are improved, and the excellent effects of high efficiency, low noise and high safety are achieved.

Description

technical field [0001] The invention relates to a blade, in particular to an ultra-low noise concave-convex bionic type subway tunnel axial flow ventilation motor blade. Background technique [0002] Subway / tunnel axial flow fans are mainly used for ventilation and fire-fighting and smoke exhaust in underground or closed spaces of urban rail transit and highways / railways. The noise characteristics of the circulation fan itself, under the same air volume and wind pressure, the noise is generally about 10dB(A) higher than that of the centrifugal fan, and there is also a parallel operation condition. At this time, the noise will be higher than that of a single fan. Increase by 3dB(A), and the installation location of the subway / tunnel axial fan is usually very close to the passengers and the surrounding residents, according to the highest requirements in Table 1 of GB 3096-2008 "Environmental Quality Standard for Acoustics", category 0 The area requires that the wind pavilion ...

AI Technical Summary

Problems solved by technology

[0003] (1) Taking the heat exhaust fan in daily operation in the subway as an example, the typical parameters are: impeller diameter 1800mm, impeller speed 985rpm, air volume 50m 3 / s, total pressure 800Pa, the blade adopts a conventional straight-twisted structure, according to GB 19761-2009 "Energy Efficiency Limits and Energy Efficiency Grades of Ventilators", the sound pressure level at the outlet of the highest-efficiency Class 1 energy-efficiency fan is about 96dB(A), After installing a 2m long piece muffler at the outlet of the fan and adding the natural attenuation of the heat exhaust duct, the noise at the wind pavilion of the subway station can reach about 45dB(A). The solution is simply to increase the length of the fan outlet muffler by 1m, but this will bring more material cost consumption, and it will also bring difficulties to the architectural layout design. At this time, how to optimize the energy efficiency of the fan through advanced and effective aerodynamic design. It is especially important to effectively reduce noise when approaching the theoretical limit

[0004] (2) Although in other industries, there are design schemes for effective noise reduction by adopting curved-sweep combination design or bionic treatment in the blade (such as sawtooth trailing edge or opening holes on the blade surface), but these designs will greatly reduce the blade itself. safety, so it is hardly used in large-load axial flow fans

[0005] Although the existing front-type swept bionic blades have lower noise than conventional straight-twisted blades (the absolute noise can be reduced by about 3dB(A)), they can also effectively improve the efficiency level and have a certain margin for preventing stall surges. However, the center of gravity of the forward-swept blade is shifted compared with the conventional straight-twisted blade, which in turn produces a larger eccentric moment, which leads to a multiplied increase in the local stress of the blade. Therefore, the lack of safety has become the biggest obstacle to its large-scale application. obstacle

[0006] The back-type swept bionic blade structure was also used in the wings of early foreign jet fighters and the compressors of their engines. Although it has a better noise reduction effect than conventional straight-twisted blades, its overall workability and stall surge margin However, it has been reduced, so whether it is the aviation industry or the fan industry, there are fewer applications in the later stage

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