Counter-rotating fan

Abstract

The invention discloses a counter-rotating fan. The counter-rotating fan comprises a first-stage impeller and a second-stage impeller which are coaxial and arranged in a spaced mode, the rotating directions of the first-stage impeller and the second-stage impeller are opposite, the first-stage impeller comprises a plurality of first blades distributed in the circumferential direction, the two sideedges, in the circumferential direction, of each first blade are a first front edge and a first rear edge correspondingly, the first front edges and the first rear edges are bent towards the rotatingdirection in the radial direction from inside to outside, the second-stage impeller comprises a plurality of second blades distributed in the circumferential direction, the two side edges, in the circumferential direction, of each second blade are a second front edge and a second rear edge correspondingly, and the second front edges and the second rear edges are bent towards the rotating direction in the radial direction from inside to outside. According to the counter-rotating fan, the efficiency of the counter-rotating fan is improved, and the rotating noise of the second blades is reducedwhile the pneumatic performance of the second blades is ensured.

Description

technical field [0001] The invention relates to the field of fan equipment, in particular to a counter-rotating fan. Background technique [0002] The counter-rotating blade technology was developed to overcome the high static pressure and provide the pressure equivalent to that of a two-stage fan. Since the counter-rotating fan has no guide vanes in its structure, it also has the characteristics of a relatively compact structure. At first, it was widely used in axial flow fans in the mining industry, etc., and then gradually expanded to military fields such as helicopters, and civilian fields such as cooling fans. [0003] Counter-rotating fans in the related art generally have the following disadvantages: [0004] 1) In the related art, because the angle between the front and rear blades of the counter-rotating fan is 0, although the front and rear blades rotate in different directions, they still overlap periodically, and the trailing edge of the blades of the previous b...

AI Technical Summary

Problems solved by technology

[0004] 1) In the related art, because the angle between the front and rear blades of the counter-rotating fan is 0, although the front and rear blades rotate in different directions, they still overlap periodically, and the trailing edge of the blades of the previous blades flows out The loss flow field of the second-stage blade will pass through the leading edge of the second-stage blade, resulting in a change in the inflow angle of attack, which will cause periodic fluctuations in the pressure distribution of the second-stage blade surface, which will cause greater noise

[0005] 2) In the related art, when the front and rear two-stage blades of the counter-rotating fan overlap, the loss flow field flowing out of the trailing edge of the previous stage blade will pass through the leading edge of the latter stage blade, resulting in a change in the inflow angle of attack, thereby reducing the flow rate of the latter stage. Aerodynamic performance of the blade

This part of the speed cannot be used in open fan products, and the resulting radial energy loss is considerable

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