RU178527U1 - CENTRIFUGAL COMPRESSOR OPERATING WHEEL - Google Patents

Abstract

The claimed technical solution relates to the field of compressor engineering, namely to the impellers of centrifugal centrifugal compressors, and can be used in the construction of single or multi-stage centrifugal compressors of high-performance gas turbine engines, as well as in units of supercharged piston engines. The technical result of the claimed technical solution aims to expand the range stable operation of the centrifugal compressor. The expansion of the range of stable operation of the compressor is achieved by the optimal location of the blades of the axial and centrifugal parts of the wheel relative to each other, which allows to obtain in the places of overlapping of their profiles an improvement in the flow of the working fluid in the area of increased aerodynamic load, leading to a stall of flow in the wheel.

Description

The claimed technical solution relates to the field of compressor engineering, namely to the impellers of centrifugal centrifugal compressors, and can be used in the construction of single or multi-stage centrifugal compressors of high-performance gas turbine engines, as well as in units of supercharged piston engines.

Known radial impellers of centrifugal compressors containing alternating main blades and shortened additional blades located between them (AS No. 817320, priority 15.11.1978, MKI F04D 29/28). A feature of this wheel is that the additional blades are shorter than the main blades and offset relative to the latter towards the exit from the wheel.

Such wheels have a lower head than axial wheels because of the absence of an axially diagonal part. The presence of a rotating cover disk increases the efficiency of the compressor, however, it should be noted that the range of stable operation of such compressors is also insufficient.

Known centrifugal compressor stage (patent for invention No. 2132002, priority 16.12.1997, IPC F04D 17/08, F04D 29/28) containing an impeller with a covering disk, radial arrangement of the blades, axial inlet flow, the angles of entry of the blades 30 ° -40 °, the angles of exit of the blades 30 ° -35 °, and a rotating guide vane (VNA) with blades mounted in the axial part of the stage between the covering disk and the sleeve. Moreover, the VNA blades have identical corresponding angles of inclination in different sections along the height between the middle line of the blade and the circumferential direction at the entrance and exit of the VNA and are installed along the output edges at the boundary of the curved bezoplatochny section of the wheel.

Such wheels have a high head and high working efficiency, however, the range of operation of such a compressor is insufficient due to the formation of vortices due to the presence of angles of attack of the flow on the blades in some operating modes. However, it should be noted that such wheels have a very complex manufacturing technology, which makes them very expensive, they are practically not used in mechanical engineering.

The closest to the claimed technical solution for the combination of essential features is the turbocharger impeller (utility model patent No. 103148, priority 23.06.2010, IPC F04D 29/44), consisting of input axial-diagonal and output centrifugal parts, which are made in the form of disks with curved working blades of the “blisk” type, with the blades of the axially diagonal part being offset relative to the blades of the centrifugal part in the circumferential direction. Moreover, in the projection onto the meridional plane, the output edges of the blades of the axial part intersect with the input edges of the blades of the centrifugal part, and the design angles of the output edges of the blades of the axial part are different from the design angles of the input edges of the blades of the centrifugal part.

Such wheels have high efficiency and high head value, which reduces the range of operation of the compressor.

The technical result of the claimed technical solution is aimed at expanding the range of stable operation of a centrifugal compressor.

The specified technical result is achieved by the fact that in the impeller of the compressor, consisting of the input axial and output centrifugal parts, which are made in the form of disks with curved working blades, and in the projection onto the meridional plane, the output edges of the blades of the axial part intersect with the input edges of the blades of the centrifugal part, the maximum overlap at the periphery of the blades in the axial direction is 0.2-0.5 of the axial length of the flowing part of the impeller, osediagonal at the base of the blades and centrifugal wheel units overlap offline, the interscapular channel between the concave surface portion osediagonalnyh blades and a convex surface portion of the centrifugal vanes overlap in places equidistant and has a width at the inlet at the periphery of 0.1-0.2 step interblade channel number of blades osediagonalnyh portion. In addition, the blades of the centrifugal part have two rows of alternating blades of different lengths, with a number of short blades located at some distance from the overlap of the blades of the axial and centrifugal parts of the wheel.

The expansion of the range of stable operation of the compressor is achieved due to the optimal location of the blades of the axial and centrifugal parts of the wheel relative to each other, which allows to obtain an improvement in the flow of the working fluid at the areas of increased aerodynamic load at the points of overlap of their profiles, which leads to a disruption of the flow in the wheel.

The claimed technical solution is illustrated by drawings, where:

in FIG. 1-2 shows an example of a specific implementation, which illustrates the essence of the claimed technical solution, the possibility of technical implementation and the achievement of the claimed technical result;

in FIG. 1 shows the axial and centrifugal parts of the impeller in projection onto the meridional plane;

in FIG. 2 schematically shows the installation of a profile lattice of a rotating guide vane (VNA) and a double-row wheel lattice with overlapping profiles on the peripheral section of the meridional contour.

The impeller of a centrifugal axial radial compressor consists of a rotating guide apparatus 2 with blades 3, the inlet sections of which provide continuous flow at the inlet and the wheel 1 with a double-row or single-row grating of profiles 4, 8. The straight-line output edges 6 of the VHA 3 blades are inclined towards the flow outlet, and rectilinear inlet edges 7 of the blades 6 of the first row of the impeller 1 are inclined towards the inlet of the flow, thus forming an overlap of 3, 6 profiles maximally on the periphery of the flow part, where there is a separation flow.

In the place of overlapping profiles on the periphery of the blades between the back of the blades of the impeller and the trough of the BHA blades, a channel 5 is formed with a width a equal to 0.1-0.2 of the pitch of the BHA blades on the outer diameter, through which air passes, stabilizing the boundary layer in the zone of flow stall blade 4 and extends the range of stable operation of the compressor. The interscapular channel 5 has a cylindrical section in the shape of a confuser with a degree of confusivity of 1.05-1.5.

Claims (1)

The impeller of the compressor, consisting of the inlet axial and outlet centrifugal parts, which are made in the form of disks with curved working blades, in the projection onto the meridional plane, the output edges of the blades of the axial part intersect with the inlet edges of the centrifugal part blades, characterized in that the centrifugal part blades have two a series of alternating blades of different lengths, long blades in the meridional plane intersect in the axial direction with a number of blades of the axial diagonal part of the wheel, maxim the axial overlap at the periphery of the blades in the axial direction is 0.2-0.5 of the axial length of the flowing part of the impeller, there is no overlap at the base of the blades of the axial and centrifugal parts of the wheel, a number of short blades is at some distance from the overlap of the blades of the axial and centrifugal parts wheels, while the interscapular channel between the concave surface of the blades of the rotating guide vane and the convex surface of the wheel blades at the overlapping points is equidistant, and has an entrance width de at the periphery of 0.1-0.2 steps of the interscapular canal.

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