CN108331616B - A disc structure of a disc turbine - Google Patents

Abstract

The invention discloses a disc structure of a disc turbine, which includes a disc, a disc flow channel and a gasket. The disc includes a disc outer edge area, a disc main body area, a disc exhaust hole and a disc shaft. hole. The discs and spacers are arranged at intervals and are installed concentrically on the shaft. The outer edge of the discs adopts sharp corners, arcs, elliptical arcs, etc. The thickness of the discs can be equal, or it can be along the radial direction of the disc. The inner thickness is reduced, and along the rotation direction of the disc during installation, the exhaust holes of the disc differ by a certain angle in the circumferential direction. The disk structure effectively reduces the energy loss of the working fluid entering the disk flow channel from the nozzle or the volute and the working fluid leaving the disk flow channel in the existing disk turbine structure and the flow of the working fluid on the disk. The flow loss in the disc turbine significantly improves the flow efficiency and overall aerodynamic performance of the disk turbine.

Description

A disc structure of a disc turbine

technical field

The invention relates to a disc structure, in particular to a disc structure for improving the flow efficiency of a vaneless turbine.

Background technique

The disc turbine adopts a bladeless turbine structure. There are multiple discs arranged axially on the rotating shaft. The distance between adjacent discs is very small. Holes, several nozzles or volutes are arranged on the outside of the disc, and the entire rotating part is enclosed in the casing.

The working fluid of the disk turbine expands and accelerates in the nozzle blade channel or the volute. Depending on the fluid viscosity, when flowing through several gaps formed by multiple disks, it will drag the disk and make it rotate around the axis. Convert the thermal energy of the fluid into mechanical work, and finally flow out from the exhaust holes arranged on the disc.

At present, the disk of a disk turbine is composed of multiple concentric disks. There are several exhaust holes in the center of the disk. The outer edge of the disk has not been processed and has a blunt edge. The outer side of the track is flush, and the main part of the disk is of equal thickness. In addition, each exhaust hole of the disk is installed at the same circumferential position. From the perspective of the work principle of the disk turbine, the disk turbine expands and accelerates through the volute or the nozzle, and the speed of the working medium reaches the maximum at the inlet of the disk, and flows into the disk flow channel in a nearly tangential direction. The trajectory of the helix flows, and finally flows out of the exhaust hole of the platter. When the working fluid flows from the nozzle into the flow path of the disk, since the outer edges of each disk are flush, the working fluid will stagnate at the outer edge of the disk, resulting in energy loss. The working fluid flows in the disc flow channel. As the working fluid flows to the outlet of the wheel disc, the thickness of the velocity boundary layer increases, and the boundary layers on both sides of the disc flow channel will interfere with each other, reducing the turbine's working ability, that is, increasing the working fluid. Flow loss in roulette. In addition, the speed of the working fluid in the wheel disk is mainly tangential velocity, and the axial velocity is very small, so it is difficult for the working fluid to flow out of the disc exhaust hole, and a large energy loss will be generated here.

Therefore, it is an urgent problem to be solved in the research of disk turbine to propose a structure that can effectively reduce the energy loss of the disk.

Contents of the invention

The object of the present invention is to provide a disc structure of a disc turbine.

To achieve the above object, the present invention adopts the following technical solutions:

Disclosed is a disk structure of a disk turbine, which includes a plurality of coaxially rotatable disks and disk flow channels arranged on the end faces of the disks, and the position on the disks is close to the rotation center of the disks ( Surrounding the shaft hole set at the rotation center of the disk) is provided with an exhaust hole communicating with the flow channel of the disk, and the exhaust holes on adjacent disks differ by a certain angle in the circumferential direction and partially overlap each other. The outer edge of the sheet protrudes outwards to form a shape in which the edge of the axial section is high in the middle and low at both sides.

Preferably, a gasket coaxially fixed to the disk is provided on the end face side of the disk, and the ratio of the thickness of the gasket to the radius of the disk is 0.004-0.06.

Preferably, the ratio of the thickness of the disc to the radius of the disc is 0.01-0.06.

Preferably, the edge of the axial section is pointed, circular or elliptical.

Preferably, the thickness of the disk at different positions on the disk is equal, or the thickness of the disk decreases as the distance from the center of rotation of the disk decreases.

Preferably, the number of discs is 2-20, and the number of exhaust holes on the disc is 2-8.

The turbine includes a casing and a volute or a nozzle arranged in the casing, the disc structure is arranged in the nozzle or the volute, the gap between adjacent disks and the gap between the outermost disk and the casing The gaps respectively constitute the disk flow channel (that is, the disk flow channel is located on the side of the disk end face), and the working fluid of the turbine enters the disk flow channel from the nozzle or volute and flows out through the exhaust hole.

Preferably, the size of the gap between the adjacent disks is determined by the thickness of the gasket, and the size of the gap between the outermost disk and the housing is smaller than or equal to the size of the gap between adjacent disks.

The beneficial effects of the present invention are reflected in:

The disk structure of the present invention can effectively reduce the energy loss in the process of the working fluid entering the disk flow channel from the nozzle or volute and the working fluid leaving the disk flow channel in the disk turbine, and significantly improves the performance of the disk turbine. Flat flow efficiency and aerodynamic performance.

Description of drawings

Fig. 1 is a schematic diagram of a longitudinal section of a disk turbine whose outer edge profile is a sharp angle;

Fig. 2 a is the three-dimensional solid figure (end view) of disc turbine wheel disc;

Fig. 2b is a three-dimensional solid figure (side view) of the disk turbine wheel;

Fig. 3 is a schematic diagram of outer edge molding lines of different types of discs;

Fig. 4 is a schematic diagram of the longitudinal section of the roulette in which the thickness of the disc varies with the position on the disc;

In the figure: 1 is the disc, 2 is the gap between adjacent discs; 3 is the gap between the disc and the housing, 4 is the gasket, 5 is the rotating shaft, 6 is the upstream of the wheel, and 7 is the housing , 8 is the outer edge area of the disc, 9 is the main body area of the disc, 10 is the exhaust hole, 11 is the shaft hole, 12 is the sharp-angled line, 13 is the arc-shaped line, and 14 is the elliptical arc-shaped line.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, the present invention provides a disc structure for improving the flow efficiency of a disc turbine, including a disc 1, a disc flow channel and a gasket 4, and the discs 1 and gaskets 4 are alternately arranged at intervals. The two discs and gaskets together form a wheel, which is concentrically installed on the rotating shaft 5, and finally packaged in the turbine casing 7 together with the volute or nozzle upstream of the wheel 6. The disc flow channel formed at the gap 2 between adjacent discs is composed of two rotating disc end faces, and the disc flow channel formed at the gap 3 between the outermost disc and the housing 7 , consisting of a rotating disc end face and a fixed housing inner wall. The disc 1 is disc-shaped, its side is the disc outer edge area 8, and its end face is the disc main body area 9, and the center of the disc main body area 9 is provided with a shaft hole 11 for connecting the rotating shaft 5, several (for example, 3) ) exhaust holes 10 are located in the main body area 9 of the disc, and are evenly distributed around the outer side of the shaft hole 5 . The thickness of the disk 1 should comprehensively consider the processing and installation accuracy of the disk and the aerodynamic performance of the turbine, and the ratio of the thickness of the disk to the radius of the disk is between 0.01 and 0.06. The thickness of the gasket 4 determines the size of the gap 2 between adjacent disks, which should not be too large or small. The ratio of the thickness of the gasket to the radius of the disk is between 0.004 and 0.06. The outermost disk and the shell The size of the gap 3 between the discs should be smaller than or equal to the size of the gap 2 between the adjacent discs, so as to avoid the working ability and turbine Efficiency drops.

As shown in Figure 2a and Figure 2b, the gasket 4 is located outside the shaft hole 11, and the exhaust holes 10 are arranged along the outside of the gasket 4. When the wheel is installed, along the direction of rotation of the wheel, each disc 1 The exhaust holes 10 are evenly staggered at a certain angle in the circumferential direction (the staggered angle is related to the tangential velocity of the working fluid at the outlet of the wheel disk, the greater the tangential velocity, the larger the staggered angle), forming a flow channel similar to a blade area, which effectively avoids the phenomenon that the tangential velocity of the working fluid decreases sharply when the working fluid flows out of the wheel disk from the disk flow channel, reduces the energy loss in the process of the working fluid flowing out, and improves the aerodynamic performance of the disk turbine.

As shown in Figure 3, the outer edge area 8 of the disc can adopt a sharp-angled line 12, an arc-shaped line 13, or an elliptical arc-shaped line 14, and form a high center and low sides on the axial section of the outer edge surface of the disc. The convex edge can effectively reduce the energy loss during the process of the working fluid entering the disc from the nozzle or volute, significantly reduce the stagnation of the working fluid on the surface of the disc, and greatly improve the thermal power conversion efficiency of the disc turbine. It is especially suitable for one-to-many nozzle inlet disk turbines and volute inlet disk turbines. Among them, the pointed line 12 is determined by the disc thickness and the angle between the two sharp lines, the arc shaped line 13 is determined by the disc thickness, and the elliptical arc shaped line 14 is determined by the disc thickness and ellipticity. Decide.

As shown in Figure 4, in addition to adopting the same thickness, the disc main body area 9 can also adopt a variable thickness design. As the working fluid flows to the outlet of the wheel disc, that is, as the distance from the center of the rotating shaft decreases, the thickness of the disc decreases, and the disc thickness decreases. The disc gap is increased, which can ensure that the boundary layers on both sides of the disc flow channel will not interfere with each other, and avoid the decline in workability. The method of compression molding can be used for the processing of discs with variable thickness, which can be more conveniently manufactured. .

Claims (8)

1. A disk structure for a disk turbine, comprising: the wheel disc structure comprises a plurality of coaxially rotatable discs (1) and disc flow channels arranged on the end face sides of the discs (1), wherein exhaust holes (10) communicated with the disc flow channels are formed in positions, close to the rotation center of the discs, of the discs (1), the exhaust holes (10) on adjacent discs (1) are staggered by a certain angle in the circumferential direction and are partially overlapped, the staggered angle is related to the tangential speed of working media at a wheel disc outlet, the greater the tangential speed is, the greater the staggered angle is, the outer edge of each disc (1) outwards protrudes to be in a shape with a middle high side and two sides low in the edge of an axial section; as the distance from the rotation center of the disk (1) decreases, the disk thickness decreases.

2. A disk structure for a disk turbine according to claim 1, wherein: a gasket (4) coaxially fixed with the disc (1) is arranged on the end face side of the disc (1), and the ratio of the thickness of the gasket (4) to the radius of the disc (1) is 0.004-0.06.

3. A disk structure for a disk turbine according to claim 1, wherein: the ratio of the thickness of the disc (1) to the radius of the disc (1) is 0.01-0.06.

4. A disk structure for a disk turbine according to claim 1, wherein: the edge of the axial section is sharp, circular or elliptic.

5. A disk structure for a disk turbine according to claim 1, wherein: the number of the discs (1) is 2-20, and the number of the exhaust holes (10) on the discs (1) is 2-8.

6. A disk turbine, characterized by: the turbine wheel disc comprises a plurality of coaxially rotatable discs (1) and disc flow passages arranged on the end face sides of the discs (1), wherein exhaust holes (10) communicated with the disc flow passages are formed in positions, close to the rotation center of the discs, of the discs (1), the exhaust holes (10) on adjacent discs (1) are staggered by a certain angle in the circumferential direction and are partially overlapped, the staggered angle is related to the tangential speed of working media at a wheel disc outlet, the larger the tangential speed is, the larger the staggered angle is, and the outer edge surface of the discs (1) is outwards bulged to be in a shape with a middle high and two sides low; as the distance from the rotation center of the disk (1) decreases, the disk thickness decreases.

7. A disk turbine according to claim 6, wherein: the turbine comprises a shell (7) and a volute or a nozzle arranged in the shell (7), the wheel disc is arranged in the nozzle or the volute, a disc flow channel is respectively formed by a gap between adjacent discs (1) and a gap between the outermost disc (1) and the shell (7), and working medium of the turbine flows out of the wheel disc from the nozzle or the volute into the disc flow channel through an exhaust hole (10).

8. A disk turbine according to claim 7, wherein: the size of the gap between the outermost disc (1) and the case (7) is smaller than or equal to the size of the gap between adjacent discs (1).

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