Centrifugal impeller

Abstract

The invention discloses a centrifugal impeller. The centrifugal impeller is used for a volute-free centrifugal fan. The impeller comprises an impeller cover, and an impeller disc, multiple blade setsare arranged between the impeller cover and the impeller disc, all the blade sets are evenly distributed in the circumferential direction, each blade set comprises a long blade and two or more short blades, all the short blades in the blade set are located on one sides of the force suction faces of the long blades, the long blades and the short blades are in wing shapes, two or more short blades in the blade set can limit the airflow between the long blades, each short blade can avoid the secondary flow on the previous-stage blade force suction face and the vortex nearby the force suction face, the secondary flow and the vortex losses in the centrifugal impeller can be greatly reduced, the centrifugal impeller efficiency is improved, and the impeller noise is reduced.

Description

technical field [0001] The invention relates to the technical field of fluid machinery, in particular to a centrifugal impeller. Background technique [0002] The volute-less fan has the advantages of large air volume and simple structure, and is widely used in air coolers, exhaust fans, air conditioners and other equipment. The volute-less fan has low efficiency during the rotation of the impeller due to the lack of a volute outside the impeller. The power loss in the fan mainly comes from separation loss, impact loss, secondary flow loss and wake loss. [0003] In the prior art, a short blade is arranged between two long blades to reduce separation loss and secondary flow loss. During the rotation of the impeller, the width of the airflow channel gradually increases, and the airflow will thicken the boundary layer due to the decrease in flow velocity and increase in pressure, and separation will occur at the rear of the boundary layer, forming a separated vortex area, re...

AI Technical Summary

Problems solved by technology

During the rotation of the impeller, the width of the airflow channel gradually increases, and the airflow will thicken the boundary layer due to the decrease in flow velocity and increase in pressure, and separation will occur at the rear of the boundary layer, forming a separated vortex area, resulting in separation loss, resulting in Reduced impeller efficiency

In addition, the pressure of the airflow on the suction surface of the blade is low, and the pressure of the airflow on the pressure surface is high. The airflow between two adjacent blades will be shifted from the pressure surface to the suction surface, forming a secondary flow, and then generating vortices in the blade channel. Affect the efficiency of the centrifugal fan and increase the noise of the centrifugal fan

Although setting short impellers between long blades can reduce the boundary layer separation and secondary flow above the suction surface of long blades, boundary layer separation and secondary flow will still occur above the suction surface of short blades, reducing the efficiency of the impeller. This makes it impossible to completely change the uneven distribution of the flow field in the prior art

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