DE102010056557A1 - Radial turbine for use in organic rankine cycle system for conversion of flow energy of working medium into torque to drive electrical generator, has conducting body, where steam operatively circulates around sides of conducting body - Google Patents

Abstract

The turbine has a conducting body including an edge pointing in a radial direction to a rotational axis of an impeller (2), and another edge pointing in a same direction as the rotational axis. The conducting body operatively directs steam flowing out of channels (20) of blades (21) from the radial direction in an axial direction. The steam operatively circulates around a side, which points towards the rotational axis, and an opposite side of the conducting body. Permanent magnets are provided on a shaft, which is connected with the impeller. An independent claim is also included for a compressor including steam flowing against a direction described in a turbine.

Description

definition

As a turbine is here called a system in which steam flows under pressure, in a fixed nozzle system (Leitbeschaufelung) relaxed and thereby accelerated. After the nozzle system, the steam over a rotating blade system (blading) deflected, possibly further relaxed, while its flow energy through the blades to a connected shaft from. The rotational energy is then transmitted by the shaft for further use. U. a. can be powered by the shaft generators for power generation.

Radial turbines are compared to axial turbines characterized in that the steam moves through the nozzle system to the axis of rotation of the impeller out and flows after use of the flow of energy parallel to this axis of rotation.

An ORC system is characterized by the presence of evaporators, condensers, turbines and pumps in which a medium other than water, for the purpose of converting thermal energy into electrical energy, changes states from liquid to gaseous and vice versa.

application

Radial turbines are often used in ORC systems with low power to drive an electric generator application. By means of these ORC systems z. B. from the waste heat of internal combustion engines additionally obtained electrical energy.

Both nozzle rings and paddle wheels of radial turbines can often be inexpensively manufactured as a prismatic body usually from one piece.

The invention causes by simple means by an inexpensive additional part an increase in efficiency of such turbines and thus the entire ORC systems.

Brief description of the drawings

1 Prior Art - Cross-sectional view of a conventional nozzle vane system of a turbine with steam flow below the speed of sound. You can see the 90 ° in the axial direction different angle of the blade inlet and outlet edges.

2 Prior Art - The cross-sectional view shows a supersonic jet nozzle vane system without additional measures to even out the vapor flow after passing the impeller.

3 ) Prior Art - Shows the paddle wheel and the diffuser of 2 ) are incorporated in the diffuser Strömungsleitkörper to reduce vortex formation.

4 ) Shows the system of 2 ) with the guide bodies according to the invention located axially inside the blade wheel.

5a ) Shows a magnified section 4 ) to illustrate the effect of the guide body.

5b ) Shows a part of the blades of the paddle wheel which have been cut transversely to the blade axis to show their geometry.

State of the art

1 ) A number of radial turbines have blades ( 21 ), whose edges are aligned axially on the steam inlet and point at the steam outlet in the radial direction. The paddle wheel ( 2 ) of such a turbine is then designed similar to the impeller of a compressor, in which the steam, driven by the blades, flows in the opposite direction to the turbine set direction.

The steam flow ( 51 ) is already inside the blade ( 21 ) and is after exiting the blade channels ( 20 ) already directed axially to the paddle wheel ( 53 ).

This type of bucket wheels or blading is only suitable for steam speeds below the speed of sound.

2 ) For supersonic flows through the impeller ( 2 ) are usually both the flowed and the downstream edges of the blades ( 21 ) and thus these themselves parallel (axially) aligned with the shaft.

The majority of the steam flow ( 51 ) is only after passing the blades ( 21 ) or of the blade channel ( 20 ) is directed parallel to the axis of rotation of the impeller ( 53 ). This usually produces unwanted eddies on the outer deflection edge ( 54 ), which convert the still usable flow energy only into heat.

3 ) Known measures to reduce this effect of vortex formation ( 54 ) is a in the paddle wheel ( 2 ) along the axis of rotation incorporated curved cone and the introduction of guide bodies ( 31 ) in the flow ( 53 ) in the discharge channel or diffuser ( 4 ) behind the paddle wheel. Despite these measures, residual vertebrae remain ( 54 ). In particular, the geometrically predetermined large difference between the radius of curvature of the impeller cone and the inner edge of the bandage ( 22 ) over the blades ( 21 ) and a high outflow velocity prevent a uniform outflow of steam.

Description of the invention

4 . 5 ) According to the invention, the radial flow from the steam flow ( 53 ) immediately after the blades axially by Leitkörper ( 31 ) divided several times and still largely within the paddle wheel ( 2 ) is directed parallel to its axis of rotation.

The one or more guide bodies ( 31 ) are ring-shaped. The profile of the rings is streamlined. The edge facing the paddle wheel is curved radially away from the center. The edge located on the axial opposite side points away from the impeller. The curvature of the profile of the guide body is designed so that the steam flowing around it ( 53 ) is steered continuously parallel to the machine axis.

If several annular guide bodies ( 31 ), the trailing edges of these bodies have different diameters, while it is expedient that the leading edges have the same diameter and are positioned as close as possible to the trailing edges of the blades.

The guide body or rings ( 31 ) 32 ) are over bridges ( 33 ) preferably connected to the steam housing or the diffuser of the turbine, so that forces acting on it due to the deflection of the steam are not transmitted to the shaft. The attachment to the steam housing can also be used as a ring ( 34 ).

It is also conceivable to attach these rings to the paddle wheel so that they rotate with it.

LIST OF REFERENCE NUMBERS

1

Düsenring

2

Laufrad

3

Leitkörper

4

Diffuser

5

Strömungsrichtung

6

Abstände

10

Düsenkanal

11

Abdeckung der Düsen

20

Schaufelkanal

21

Schaufel

22

Bandage an Schaufel

30

Kanal zwischen den Leitkörpern

31

Leitkörper 1

32

Leitkörper 2

33

Verbindungssteg zwischen den Leitkörpern und der Befestigung

34

Befestigungsring der Leitkörper

40

Kanal im Diffuser

50

Strömung im Düsenkanal

51

Strömung im Schaufelkanal

52

Strömung zwischen den Leitkörpern

53

Strömung im Diffuser

54

Strömungsablösung im Diffuser

60

Schaufelhöhe am Schaufelkanalaustritt

61

Axialer Abstand zwischen Schaufelradscheibe und Leitkörper 1

62

Axialer Abstand zwischen Leitkörper 1 und Leitkörper 2

63

Axialer Abstand zwischen Leitkörper 2 und dem Schaufelkopf bzw. der Bandage

Fig. 1) section through parts of a conventional axial turbine for subsonic flow Fig. 2) Section through parts of a conventional axial turbine for supersonic flow. 3) Section through parts of a supersonic flow axial turbine with conventional vane blades after the vane wheel. 4) Section through parts of an axial turbine for supersonic flow with guide bodies according to the invention in the SchaufelradFig. 5a) Details from FIG. 4) FIG. 5b) section through blades of the blade wheel from FIG. 5a) FIG. 1-Fig. 5) Name of the details

1

nozzle ring

2

Wheel

3

conducting body

4

diffuser

5

flow direction

6

distances

10

nozzle channel

11

Cover of the nozzles

20

blade channel

21

shovel

22

Bandage on shovel

30

Channel between the guide bodies

31

Guide body 1

32

Guide body 2

33

Connecting web between the guide bodies and the attachment

34

Fixing ring of the guide body

40

Channel in the diffuser

50

Flow in the nozzle channel

51

Flow in the blade channel

52

Flow between the guide bodies

53

Flow in the diffuser

54

Flow separation in the diffuser

60

Bucket height at the bucket channel outlet

61

Axial distance between paddle wheel disk and guide body 1

62

Axial distance between the guide body 1 and guide body. 2

63

Axial distance between the guide body 2 and the blade head or the bandage

Claims (5)

Turbines having at least one guide body, of which one edge in the radial direction to the axis of rotation of the impeller and the other edge in the same direction as the Rotation axis shows, said guide body operatively directs the steam flowing from the blade channels from the radial direction in the axial direction and both the side facing the axis of rotation of the blade wheel and the opposite side of the guide body are operatively flowed around by steam. 1. The turbines according to claim 1, which have a plurality of guide bodies as described in FIG. 1, whose edges pointing in the direction of the rotation axis have a different radial distance therefrom and whose edges located at the opposite ends preferably point in the radial direction to the blades of the paddle wheel. Turbines with located on the shaft connected to the paddle wheel permanent magnets, which are also referred to as so-called turbogenerators on the turbine part of the claims of 1 and 2 apply. ORC systems that contain components after 1st, 2nd or 3rd. Compressors that are constructed like 1st, 2nd or 3rd, but in which the steam flows functionally contrary to the direction described in the turbines.

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