RU1800130C - Axial compressor - Google Patents

Abstract

Usage: compressor and fan - building. SUMMARY OF THE INVENTION: to increase the reliability of an axial compressor by reducing the vibrational stresses in the impeller blades, the pitch of the grating of the plates installed in the annular groove located in the housing in the region of the input edges of the impellers is selected from a ratio of 2 k, where R is the radius of the impeller; P-rated impeller speed. Hz; f is the natural frequency of the impeller blades. Hz; to 1.2. 3 - coefficient of multiplicity. 2 ill.

Description

The invention relates to a compressor construction and can find wide application in axial compressors (OK).

The aim of the invention is to increase the reliability of an axial compressor by reducing the vibrational stresses in the impeller blades and to eliminate these drawbacks.

In FIG. 1 schematically shows a longitudinal section of a step OK; figure 2 - section aa in fig. 1.

The axial compressor consists of a plurality of working blades 1, guide vanes 2 installed in the housing 3. The housing 3 comprises an annular cavity 4 in communication with the flow part of the compressor through slots 5 of the grate formed by the plates 6.

The plates 6 are installed at an angle p ° 30-50 ° to the radius of the housing 3 and in the scan on the tangential plane form an angle exceeding no more than 20 °

h

fe

outlet angle of the flow from the vanes of the guiding apparatus. The lattice of the plates 6 is made with a ratio of the pitch to the thickness of the plates 6 equal to 2.5-3.0, and the ratio of the radial length of the plates b to the width of the slots 5 is at least 2.0, the axial length of the lattice of the plates 6 is at least 0, 9 (from the chord of the working blades 1). The degree of overlap of the input edges of the working blades 1 by the grating of the plates b in the axial direction is (0.4-0.60) VK and the height of the cavity 4 is at least 0.2 V. The thickness of the plates 6 and the width of the slit 5 is selected from the ratio

tp 2 where R is the radius of the impeller;

pr - nominal frequency of rotation of the impeller ;.

f is the natural frequency of the impeller blades; "

00

oh oh

W

about

k 1,2,3, ... is the coefficient of multiplicity.

Through slots 5 in the grid of plates 6, gas flows from the annular cavity A into the flowing part to the inlet edge of the working blade 1, forming a system of jets. Since the thickness of the plates b and the width of the slots 5 satisfy the ratio, the jet system dampens the resonant vibrations of the blade 1.

Thus, the use of an O K containing an annular cavity communicating with the flowing part through slots between the plates forming a lattice with characteristics satisfying the condition makes it possible to reduce stresses during resonance vibrations of the working blades and thus reduce the number of breakdowns of the OK blade. As a result, the reliability of OK is improved.

Claims (1)

The claims An axial compressor comprising a casing, an impeller mounted thereon and a guide vane, an annular cavity made in the casing from the side of the flow part, in which the plates forming the grating are installed at an angle of 30 ... 50 ° to the radius of the casing, with a pitch ratio to the thickness of the plates is equal to 0 5 2.5 .., 3.0 and the ratio of the radial length of the gap between the plates to its width of not less than 2.0, the axial length of the lattice and the height of the free cavity are respectively not less than 0.9 and not less than 0.2 from the axial projection of the chord of the blade of the impeller on the periphery, and the area of overlap of the input edges of the blades of the impeller of the impeller of the plate lattice in the axial direction is 0.25 ... 0.45 from the axial projection of the chord of the blade of the impeller on the periphery, characterized in that, in order to improving the reliability of the compression compressor by reducing vibration voltage in the impeller blades, the lattice pitch tp is chosen from the relation twenty V where R is the radius of the impeller; pr is the nominal rotational speed of the impeller, Hz; f is the natural frequency of the impeller blades, Hz; to 1,2,3 - the coefficient of multiplicity.