SU1682604A1 - Axial turbo-machine stage - Google Patents

Abstract

The invention relates to turbine engineering and can be used to reduce the low frequency vibration of turbomachine rotors. The purpose of the invention is to increase reliability. As a result of mixing the steam flows into the overband seal chamber through the axial clearance and the bypass channels made in the diaphragm rim, the circumferential flow rate decreases, resulting in a corresponding decrease in disturbing forces causing low-frequency rotor vibration, 2 Il.

Description

The invention relates to turbine construction and can be used to reduce the low frequency vibration of high power turbomachine rotors.

The purpose of the invention is to increase reliability.

FIG. 1 shows the proposed level, longitudinal section; figure 2 - section aa in figure 1.

The stage contains a diaphragm 1 having guide vanes 2 and a rim 3, a wheel 4 with working blades 5, an overhead seal 6 including an axial sealing ridge 7 and radial sealing ridges 8. In the rim 3 of the diaphragm 1 in the end surface of the nozzle channels, formed by guide vanes 2, inclined bypass channels 9 are made. The axes of the bypass channels 9 are located along a generatrix of a cone whose axis coincides with the axis of the stage. The inputs of the bypass channels 9 are made in the area

output edges of guide vanes 2 in each nozzle channel

Due to such a step, the space formed by the chamber 6 first along the working medium communicates with the flow part of the step through the gap between the rim 3 of the diaphragm 1 and the axial ridge 7, as well as through the inclined bypass channels 9. The channels 9 are uniform in the rim 3 of the diaphragm 1 circumferentially, in this case, their flow area is selected so that in the seal chamber 6 the circumferential flow rate of the working medium is at the level v / 2, where v is the circumferential speed of the rotating seal surface.

Step works as follows.

The steam passes through the nozzle channels formed by the guide vanes 2 and falls on the working vanes 5, creating a torque. Part of the steam, having a high circumferential velocity, falls into the first along the steam chamber seal 6

(L

with

about

00 fsj Oh o

N

through the gaps formed by the axial ridge 7 and the rim 3 of the diaphragm 1. As a result of the fact that the axes of the bypass channels 9 are located along a generatrix of a cone whose axis coincides with the axis of the step, the other part of the steam entering the specified chamber through the channels 9 has zero component of peripheral speed. Due to this, when steam is mixed, the average circumferential speed in the first along the steam chamber of the seal 6 decreases to a level equal to v / 2, which leads to a decrease in disturbing forces causing low frequencies

Claims (1)

rotor vibration and seals 6 arising from circumferential pressure unevenness in the chambers at a high circumferential flow rate of the working medium. Claims of the invention A stage of an axial turbomachine comprising a diaphragm of a guide vehicle, in the rim of which bypass channels are made, characterized in that, in order to increase reliability, the bypass channels are inclined, and the axes of the channels are located along a cone, whose axis coincides with the axis of the stage. FIG. 9