SU879047A1 - Centrifugal compressor radial diffusor - Google Patents

Description

1 The invention relates to the field of compressor engineering, namely to diffusers of centrifugal compressors.

Known radial diffuser centrifugal compressor, containing between the side walls of one blade crown 1.

However, such centrifugal compressors with single-sided radial diffusers have low efficiency and insufficiently wide operating ranges of characteristics, which is explained by increased losses in these diffusers due to the separation of the boundary layer in their channels due to the large extent of the inter-blade channels.

Closest to the proposed technical essence and the achieved result is a radial diffuser of a centrifugal compressor containing two concentric vane rims 2 placed between the side walls.

The main disadvantage of this diffuser is that high-pressure centrifugal compressors with a similar diffuser also have small ranges of characteristics and insufficient stability margins at the operating points of the characteristics due to the fact that this diffuser is not optimal in its design parameters.

The aim of the invention is to increase the efficiency and range of operation.

5 compressor.

This goal is achieved by the fact that the exit edges of the blades of the inner rim are displaced in the circumferential direction from the entrance ridges of the blades of the outer rim with

10 of the side of their troughs for a distance of 0.2-0.75 from the step of the entrance edges of the blades of the outer rim, the area at the exit of the interscapular canals of the inner rim is 1.45-2.0 of the area per

The 15 inlets of the same channels, the throat diameter of each interscapular canal of the inner rim is 1.25-1.7 times the height of the blade of this rim at the inlet, and the ratio of areas at the exit and inlet of the interscapular canals 20, respectively, of the outer and inner rims is 2.8-3 ,five.

FIG. 1 schematically shows the proposed radial diffuser; in fig. 2 is a section A-A in FIG. one; in fig. 3 is a section BB in FIG. one; in fig. 4 shows a section B-B in FIG. I.

The radial diffuser of a centrifugal compressor contains two blade rings placed between the side walls (not shown in the drawing). Weekends

edges 1 of the blades 2 of the inner rim are displaced in the circumferential direction from the entrance edges 3 blades 4 of the outer rim from the side of their troughs 5 to a distance L of 0.2-0.75 from the pitch / entrance edges 3 of the blades 4 of the outer rim, area FZ at the exit of the interscapular channels 6 of the inner rim is 1.45-2.0 of the area FI at the entrance of the same channels 6, the diameter d of the throat of each interscapular channel 6 of the inner rim is 1.25-1.7 in height hi of the rim of this rim at the entrance, and the ratio of the area s at the exit and the area P at the entrance, respectively, interscapular to 7 canals broke: the foot of the crown and the interscapular canals 6 of the inner crown is 2.8-3.5.

With this optimal arrangement of the output edges 1 of the blades 2 of the inner rim from the entrance edges 3 of the blades 4 of the outer rim of the radial diffuser, the boundary layer is freely released from the surface of the blades 2 of the inner rim, which improves its work without impairing the work of the outer rim.

Specified optimal ratios

-; P fa

space -, - and the diameter ratio

FI n

The throat di at the inlet of the interscapular channel 6 to the height hi of the inner rim ensures optimal conditions for the joint operation of the inner and outer rims of the radial diffuser, which allows for an increase in the efficiency and expansion of the range of operation of the compressor.

Claims (2)

1. Kolschevnikov K.V. Theori and the calculation of aircraft blade machines, M., “Mashinostroenie, 1970, p. 278. 2. USSR author's certificate number 524012, cl. F 04 D 29/44, 1974. Aa S