SU1560731A1 - High-pressure cylinder of steam turbine - Google Patents

Abstract

The invention relates to steam turbine construction, in particular, to the design of two-cylinder high pressure cylinders (CVPs) with a loop arrangement, and improves the economy, reliability and maneuverability of CVPs and turbines. The HPC contains the inner and outer housings 4 and 6, between which a loop channel 7 is formed, and the first and second groups of 3 and 9 stages, the first steps 10 and 11 of which are radial-axial, and their impellers 2 and 8 are made in the form of integral dual wheels. The expansion of steam in the impeller 2 is accompanied by a decrease in its temperature by a greater amount than in the axial stage. The greatest stresses in the impeller 2 occur in the zone of low temperatures. Radial-axial stage 10 allows an increase in the initial temperature of the steam, which increases the efficiency of the CVP. Reducing the temperature gradient reduces the level of thermal stress, and reducing the length of the rotor 13 increases its rigidity and resistance to low-frequency oscillations, which increases the reliability and maneuverability of the CVP and the entire turbine. 2 Il.

Description

This invention relates to a turbo structure and can be used in double-hulled high pressure cylinders with a loop flow of steam.

The purpose of the invention is to increase efficiency, reliability and maneuverability.

Figure 1 shows the CVP with the first and second groups of stages and a forged rotor, longitudinal section; figure 2 - TsL with the first and second groups of steps and a composite rotor, a longitudinal section;

The HPC contains an inlet 1, in communication with the impeller 2 of the first group of 3 stages, housed in the inner case 4. The space 5 between the inner and outer cases 4 and 6 forms a loopback channel 7, communicated with the impeller 8 of the second group of 9 stages.

The first steps 10 and 11 of the first and second groups 3 and 9 are radial-axial. In the outer casing 6 a guide device 12 of radial-axial stage 11 is installed. Impellers 2 and 8 are made in the form of an integral dual wheel and fixed to the rotor 13 (figure 1). The rotor 13 4 (FIG. 2) can be made up of parts 14 and 15 with which the impellers 2 and 8 are connected. The latter are interconnected. In groups 3 and 9 of the steps, the remaining stages 16 and 17 (except for the radial-axial hollow of the legs 10 and 11) are axial. Between the inlet pipe 1 and the impeller 2 is a spiral chamber 18.

Integral dual radial-axial wheel (impellers) 2 and 8, in contrast to the double-flow radial axial wheel, has different geometrical dimensions of the first flow and second impellers 2 and 8 and different gas-dynamic parameters of the working fluid at the entrance to the wheels 2 and 8 and at the output of them. The geometry of the radial-axial wheels (steps) 2 and 8 and the number of axial steps 16 and 17 are determined by the distribution of the enthalpy differences.

CLV works as follows. Fresh steam through the inlet 1 is fed into the spiral chamber 18, from which the first downstream radial-axial stage 10 of the first group 3 enters the impeller 2

0

steps and dapee - in axial steps

16 of this group of 3 steps.

After the axial stages 16 of the first group of 3 stages, the pairs in the loop channel 7 rotate 180 ° and are guided into the guiding device 12 and onto the impeller 8 of the radial-axial stage 11 of the second group 9 stages and further into the axial stages

17 of the second group of 9 stages, after which the steam is removed for intermediate superheating.

The radial-axial stage-10 allows high enthalpy differences to operate with high efficiency and allows one radial-axial stage 10 to replace several axial stages 16. The axial dimensions of the rotor 13 of such a cylinder are sharply reduced. The expansion of steam in the channels of the impeller 2 or 8 of the radial-axial stage 10 or 11 is accompanied by a decrease in its temperature.

Claims (2)

The study of strength and heat transfer in the radial-axial stage 10 shows that the greatest stresses in the impeller 2 occur at a radius where the temperature of the metal is significantly lower than at the periphery of the wheel 2. Therefore, the maximum permissible steam temperature at the inlet to the radial-axial stage 10 is significantly higher than in axial stage 16, which increases the efficiency of the HPC. This temperature difference increases with increasing vapor expansion. When the steam enters the impeller 2 at high temperatures, due to a drop in its temperature during a flow in the radial direction, the maximum temperature of the rotor 13 in the zone of the first flow radial-axial stage 10 decreases and the temperature gradient of the rotor 13 decreases sharply. The temperature gradient of the rotor decreases 13 reduces the level of thermal stresses in it. Reducing the number or abandonment of axial stages 16 and 17, and reducing the length of the rotor 13 increases its rigidity and resistance to low-frequency oscillations. Reducing the temperature gradient of the rotor 13 and increasing its vibration resistance increases operational reliability, maneuverability of the HPC and the entire turbine. Claims of Invention A high-pressure steam turbine cylinder comprising an inlet. communicated with the impeller by a perk of a group of stages located in the inner case, the space between which and the outer case forms a loop channel communicated with the impeller of the second group of stages, so that, in order to improve efficiency , reliability and maneuverability, the first steps of the first and second groups are made of radial-axial, and their impellers are in the form of an integral dual wheel. 13 Editor I. Casard Compiled by V.Gutorov Tehred L. Oliynyk Proofreader S. Shevkun Order 960 Circulation 426 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and Publishing Combine Patent, city of Lviv, st. Gagarin, 101 FIG. 2 Half-full