RU1783123C - Turbomachine exhaust branch pipe - Google Patents

Abstract

Usage: in turbine engineering, in particular in low pressure cylinders of steam turbines. SUMMARY OF THE INVENTION: The shell 4 of a diffuser of an exhaust pipe of a turbomachine is made with a generatrix in the side zones varying towards the output edge. A generatrix with a minimum length is located in the plane of the horizontal connector 2. 2 zpp-fs, 2 il.

Description

Fig l

The invention relates to turbine engineering and can be used in low pressure cylinders of steam turbines.

Known exhaust pipe turbomachine containing an asymmetric annular diffuser, in which an oblique slice is made in the direction of exhaust 1,

The main disadvantage of this design is the limitation of its use by the class of turbomachines, mainly gas turbine units, equipped with an exhaust pipe with an annular diffuser. The exhaust pipes of modern steam turbines are typically made with axial radial diffuser channels.

An exhaust pipe-turbomachine is known that contains an asymmetric axial-diffuser, the contour of the upper part of which is outlined by a circle, and the lower part is made with a side cut. When this pipe contains a system of guide and power ribs 2

We consider the construction of the pipe joint and, first of all, the choice of the rib system of rigidity does not allow us to consider it effective in the transonic range of Mach numbers of the working medium.

The closest technical solution is an exhaust pipe containing a collection chamber and a diffuser formed by coaxially placed internal fairings and an outer shell with an outlet edge and side zones symmetrically to the plane of the vertical axial section of the turbomachine 3.

This design of the nozzle is off-line at low values of Mach villages (Mt2 0.6-0.7). For nozzles of powerful modern turbines, MC2 numbers 0.7-0.9 and the corresponding effects leading to a crisis decrease in efficiency are characteristic.

The purpose of the invention is to increase the efficiency of turbomachines by increasing the throughput of their exhaust pipes,

This goal is achieved in that the exhaust pipe containing a collection chamber formed by a casing with a horizontal connector, and a diffuser formed by coaxially placed inner fairing and an outer shell with an outlet edge and side zones symmetrically to the vertical plane oceoofo of the turbomachine section, the diffuser axis it is placed in the openings of the horizontal connector, has a shell with a generatrix in the lateral zones that varies with the output edge, while forming with a minimum length of put in a horizontal parting plane.

5 The shell can be made with a smoothly varying length of the output edge forming along the entire perimeter with the formation of the latter in the form of a closed elliptic curve,

0 In addition, the shell can be made with channels formed by the cross section of the shell in the side zones from the side of the output edge by planes symmetrical with respect to the vertical axial

5 sections.

Using the proposed design of the exhaust pipe allows for conditions of transonic flow rates and existing overall limitations of its

0 widths expand the boundaries of the range of modes, according to the number corresponding to locking the pipe.

Figs. 1 vi 2 show the design of the proposed structures; exhaust 5 nipple nozzles.

The exhaust pipe of the turbomachine contains a collection chamber formed by a casing 1 with a horizontal connector 2, and a diffuser formed by coaxially placed inner fairing 3 and outer shell 4. The shell 4 can be made with a continuously varying length forming the output edge around the entire perimeter with the formation of the latter in

5 as a closed elliptic curve (see FIG. 1). Hi FIG. 2 shows a diagram of the exhaust pipe, where the sections of the shell 4 “of the lateral zones from the side of the outlet edge form planes symmetrical from 0 to the plane of the vertical axial section of the turbomachine,

In the exhaust pipe of the turbomachine, after its last stage, the working medium flows through a separate diffuser channel into the volume of the collection chamber with intensive swirling of the flow in it. The maximum twist intensity occurs in the region of the horizontal connector 2 of the pipe.

0 An increase in the passage areas in the collection chamber under existing dimensional restrictions, including the pipe width, contributes to a decrease in the throughput of the turbomachine through a decrease in the flow swirl intensity. Such over-expansion is achieved in the proposed design of the exhaust pipe using the shell 3 of the pipe diffuser with an elliptical outlet edge or about the form of planes symmetrical to the vertical axial section of the turbomachine.

This design allows, by reducing the tangential component of the velocity of the swirling flow in the volume of the collection chamber, to increase the cross-sectional area with a positive (flow) component of the velocity, which in turn increases the throughput of the exhaust pipe. Taking into account the flow swirl in the blade apparatus of the last stages of the turbomachine and the corresponding circumferential decrease in the expendable component of the velocity relative to the axis of symmetry in the output section of the diffuser channel, it is advisable to arrange the small axis of the shell 4 of the diffuser at an angle to the plane of the vertical axial section of the nozzle. This design is selected from the condition of maximum passage area of the collection chamber, taking into account the flow swirl behind the last stage of the turbine (angle in Fig. 2.6).

Claims (3)

SUMMARY OF THE INVENTION 1. An exhaust pipe of a turbomachine comprising a collection chamber formed by a casing with a horizontal connector, and a diffuser formed by a coaxially placed inner fairing and an outer shell with an outlet edge and side zones symmetrically to the plane of the vertical axial section of the turbomachine, the diffuser axis being placed in the plane of the horizontal casing connector, characterized in that, in order to increase the economy, the shell is made with a variable to the output edge with the length of the generatrix in the lateral zones, while the generatrix with a minimum length is located in the plane of the horizontal connector. 2. Pipe branch pop. 1, characterized in that the shell a is made with a smoothly varying length of the output edge forming along the entire perimeter with the formation of the latter in the form of a closed elliptic curve. 3. A pipe according to claim 1, characterized in that the shell is made with channels formed by a section of the shell in the lateral zones from the side of the outlet edge by planes symmetrical with respect to the plane of the vertical axial section. 4