SU1454991A1 - Exhaust end of turbomachine - Google Patents

Abstract

Invention m. used in steam and gas turbines. The invention improves the efficiency of the turbomachine. The exhaust pipe 6 is located behind the turbine stage 1, and its inner and outer contours 7 and 8 form a diffuser (D) 9. The contours 7 and 8 are made based on the ratio of the outlet area to the input area D 9 depending on the relative radial clearance

Description

one

The invention relates to turbine building and can be used in steam and gas turbines.

The aim of the invention is to increase the efficiency of the turbomachine by increasing the efficiency of the exhaust pipe by optimizing its diffuser together with the afterturning stage.

FIG. 1 shows the exhaust part of a turbomachine, a longitudinal section; in fig. 2 - the same, I, II and III variants of the outer contour of the diffuser; in fig. 3 - the dependence of the coefficient („) of the total loss of the exhaust pipe on the degree of expansion of the diffuser (PD); in fig. 4 - current lines for version I of the diffuser; in fig. 5 - current lines for version II of the diffuser on a static stand; in fig. 6 - the same, on the model turbine; in fig. 7 - the dependence of the efficiency (2) of the compartment of the step-nozzle on the operating parameters (and / s)} in FIG. 8 - relative velocity values (with c / Cg) at the periphery of the entrance section of the diffuser along the height (1).

The exhaust part of the turbomachine contains the turbine stage 1 formed by the guide device 2 and the impeller 3, which is installed with a radial clearance Sf 4 relative to the stator 5. Behind the turbine stage 1 is the exhaust pipe 6 with the inner 7 and outer 8 lines, forming a diffuser 9. The outer and (or) inner contours 7, 8 are made on the basis of the ratio of the area F, at the exit to the area Fg at the inlet of the diffuser 9J, the radius of compression

o

five

0

ewx Fir

+ (123 (O, 95 ... 1.05) 45 td,

out

Fer

1 h

where 5 p / d

,; td7 ;; R

- relative radial clearance between the impeller 3 and the stator 5 (В „- periphery diameter of the entrance section of the diffuser 9);

oL "P) are the angles of exit from the blades 10 of the guiding apparatus 2 and the entrance to the blades 11 of the impeller 3 at the periphery of the turbine stage 1;

- exit area

-diffuser 9 when d. 0.

 & ЫХ1

five

0

0

F ratio

, , ...about ". is the step (Pr) expansion of the diffuser 9 at 5 p 0. The guide apparatus 2 and the impeller 3. contain blades 10 and 11. Curves 12 and 13 (Fig. 3) characterize the dependences on Pa obtained on a static bench and on a turbine . Curves 14, 15 and 16 (Fig. 7) characterize the dependences of H on and / s and respectively, respectively for dl. I, II and III variants of the diffuser. 5 Curves 17, 18, and 19. (Fig. B) characterize changes in values from 1 to 1 on the natural level, on the model level, and on the static bench, respectively.,

The exhaust part of the turbomachine works as follows.

The working fluid from the impeller 3 of the turbine stage 1 and from the radial clearance 4 enters the diffuser 9

thebes. 2

1.25 2.

 1.0

0.7

 e, 9

2.0 2.7 2.2 2, J

L FIG. J

If

111

12

J

X

FIG. 6

OJB5. at 7

FSh.7

FI.5

OJ50,8

U / cfp

 ABOUT

0.5 / 1.5

The USSR

FIG, B

2.5

Claims (1)

SUMMARY OF THE INVENTION θ The exhaust part of a turbomachine, comprising a turbine stage formed by a guide apparatus and an impeller, the latter is installed with a radial clearance () relative to the stator, and an exhaust pipe located behind the turbine stage with internal and external contours forming a diffuser, characterized in that , with the aim of increasing efficiency, the ratio of the area F _{ftb) X} at the outlet of the diffuser to the area F _in at its input is determined based on the expression 20 ^ 8th ^ out.oG --- = (0.95 ..1, 05.) - = 1 + ^g * ex ^td vhL ⁴⁵ 3 «n - Ί ^{+ (y 1 '25} where 5p ⁼ p / _p 0 ~ relative radial gap between impeller and stator; the peripheral diameter of the inlet section of the diffuser, the angles of exit from the vanes of the guide apparatus and the entrance to the blades of the impeller at the periphery of the turbine stage; F “the area at the outlet of the diffuser GFI Sp = 0. FIG. 4 0.8 FIG. 8