RU2022121C1 - Two-flow radial-axial wheel - Google Patents

Abstract

FIELD: manufacture of turbines for moist-steam turbines. SUBSTANCE: wheel has load-bearing disk 1 with working blades 2 and cover disks 3 and 4. Wheel is provided with moisture separator pump 3 with reactive hydraulic nozzles 6 mounted on end surface of at least one cover disk, for example, disk 4 on side of the wheel inlet. Leading edge of each working blade 2 has edges smoothly bent in way of steam flow forming chutes located at angle of 1 to 5 deg to longitudinal axis of the wheel, thus providing for discharge of liquid to the separator pump. Grooves or projections 11 are made on inlet sections of blades and on inner surface of cover disk with moist separator pump over trajectory of water jet flow. EFFECT: enhanced efficiency. 2 cl, 4 dwg

Description

 The invention relates to the field of turbine engineering and can be used in turbines operating on wet steam in thermal and nuclear energy, in marine power plants, as well as in geothermal energy.

 Known dual-flow impeller, designed to work in a wet-steam turbine, containing in the radial part of the blade of two types: parallel to the axis of the wheel and inclined to the axis of the wheel, and the input edges of the latter are located on a larger radius than the edges of the "axial" blades.

 In such a wheel, moisture droplets coming in with a stream into all channels and interacting with inclined vanes will partially be ejected towards the coating disk and the moisture trapping chamber. At the same time, moisture droplets interacting with the blades parallel to the axis of the wheel will be ejected back into the stream and again fed into the impeller. The process will be repeated. This will lead to erosion of the working blades, and consequently, to a decrease in durability, a decrease in the reliability and efficiency of the wheel and the entire stage.

 It is also known that the prototype is a two-line radial-axial impeller designed for operation in any heat turbine, including a wet-steam turbine, containing a carrier disk with working and dividing vanes on which cover disks are mounted.

 In such a wheel, moisture droplets coming with steam to the blades are thrown back into the stream and again with steam enter the impeller. The process is repeated. Multiple collision of droplets with working blades leads to erosion of the latter. At the same time, the blades of the guiding apparatus of the turbine stage are also intensively eroded. Erosion of the impeller blades reduces its durability and reduces reliability.

 Humidity reduces the efficiency of the impeller and turbine stage.

 The aim of the invention is to increase durability, increase the reliability and efficiency of a dual-stream radial-axial impeller of a wet-steam turbine by removing moisture from the stream.

To achieve this, a wheel containing a carrier disk with rotor blades on which the cover discs are mounted is equipped with a moisture separator pump with hydraulic jet nozzles mounted on the end surface of at least one cover disc on the wheel inlet side, and the input edge of each blade is formed with a smoothly curved along the edges to form a pair of troughs arranged at an angle 1 ... 5 ^of the longitudinal wheel axis to discharge fluid to the pump-separator.

 A distinctive and fundamental feature of the proposed device is the capture (capture) of moisture drops entering the wheel, and not dumping them back into the stream.

To capture, give stability and the direction of movement of the film of water formed on the blades and the inner surface of the casing disk, grooves or relief projections are made on their surfaces along the current paths of the water jets, and the input edge of each working blade is made with edges smoothly bent along the steam to form gutters located at an angle of 1 ... 5 ^about to the longitudinal axis of the wheel with the provision of drainage of fluid to the pump-separator.

 Jet nozzles are widely known, but in the proposed device, jet hydraulic nozzles are designed to obtain additional useful work on the turbine shaft by increasing the kinetic energy and the emission of harmful mass of water entering the steam wheel.

 Figure 1 shows a double-threaded radial-axial wheel and adjacent elements of the turbine stage, a longitudinal section; figure 2 is a section aa in figure 1, a section through a jet hydraulic nozzle; figure 3 is a section bB in figure 1, a section of the input edge of the blade; in Fig.4 is a view along arrow B in Fig.1, a view of the grooves or embossed protrusions at the inlet portion of the inner surface of the cover disk of the wheel.

 The wheel contains a carrier disk 1 with rotor blades 2. Cover blades 3 and 4 are mounted on the blades. On the end surface of at least one cover disk from the wheel inlet side, a moisture shut-off moisture separator pump 5 with reactive hydraulic nozzles 6 is installed.

In the turbine casing above the pump-separator with jet hydraulic nozzles, a water collection chamber 7 is made. From the main stream of steam jet nozzles isolated hydraulic seal 8. At the entrance of the impeller is mounted a guiding device 9. The front edge 10 of each rotor blade is formed with a smoothly curved along the edges to form a pair of troughs arranged at an angle 1 ... 5 ^of the longitudinal wheel axis. In this case, the input edges of the blades may not be inclined to the axis of the wheel.

 Grooves or embossed protrusions 11 are made in the inlet portions of the blades, and grooves or embossed protrusions 12 are made along the paths of the current of the water jets at the inlet portion of the blades 12. The current path of the water jets is determined by known methods.

 Wet steam enters the vanes of the guide vane 9. When the steam expands, it condenses. Part of the moisture droplets settles on the surfaces of the guide vanes, forming thin liquid films, which, under the action of the steam flow, flow to the outlet edges and are crushed.

In the Coriolis impeller, the force presses moisture drops to the surfaces of the working blades 2. The moisture films formed in this case under the action of centrifugal forces along the grooves or relief projections 11 move to the periphery of the blades 2 and are caught by the grooves formed by the smoothly bent edges of the input edge 10 of each working blade. As the spouts are formed inclined to the wheel axis at an angle of ^about 1 ... 5, the jets of water on them and the grooves or embossed protrusions 12 flows to the pump-separator 5. thrown from the blades 2 and the inner surface of the disk 4 coating water-shutoff trapped slit pump-separator 5. From the pump-separator, water enters the jet hydraulic nozzle 6. The nozzle section is calculated only for water discharge and depends on the value of its peripheral speed, pressure of the working fluid in front of the wheel and the amount of water discharged. Water streams flowing from the nozzles at high speed create additional useful impeller torque.

 Water ejected by the jet nozzles enters the chambers 7 of its collection and is discharged.

 The proposed technical solution allows to significantly capture the moisture entering the impeller, and thereby prevent repeated collisions of drops with the blades of the wheel and virtually eliminate the collision of water drops with the blades of the guide vane.

 Reducing the number of collisions of water droplets with the blades of the impeller and the guide vane will increase the erosion resistance of the wheel and the entire stage, which will increase the durability and increase the reliability of the turbine stage.

 The device allows due to the ejection of water from the stream through the jet hydraulic nozzles to obtain additional useful torque on the turbine shaft.

 Removing moisture from the steam stream will increase the efficiency of the wheel and the entire turbine stage.

 In multi-stage cylinders with a two-line radial-axial stage of separation of moisture at the inlet, it will increase the durability, increase the reliability and efficiency of subsequent axial stages of the cylinder and the entire turbine unit. Moreover, the economic effect of the use of the device will be greater, the higher the steam humidity at the entrance to the stage.

Claims (2)

1. TWO-FLOW RADIAL-AXIAL WHEEL of a humid-steam turbine, containing a bearing disk with rotor blades on which cover disks are installed, characterized in that, in order to increase durability, reliability and economy, it is equipped with a moisture separator pump with reactive hydraulic nozzles mounted on the end surface of at least one cover disk from the wheel inlet side, and the input edge of each working blade is made with edges smoothly bent along the steam with the formation of grooves x at an angle of 1 - 5 ^o to the longitudinal axis of the wheel with the provision of drainage of fluid to the separator pump.  2. The wheel according to claim 1, characterized in that the inner surface of the casing disk on which the separator pump is mounted, and the inlet sections of the blades are made with grooves or embossed protrusions to drain the formed streams of water.

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