EP2659093B1 - Turbomachine - Google Patents

Description

The invention relates to a radial turbine, comprising a housing, which has a housing channel for the inflow of working fluid and a diffuser having a channel for the discharge of working medium, wherein in the housing an impeller on a rotatable about an axis of rotation rotatable impeller is positioned, wherein on the impeller, a plurality of blades are arranged which form blade channels having a rotational axis facing blade channel opening for the passage of working fluid to the channel for the discharge of working fluid, wherein the channel for the discharge of working fluid has an impeller-side opening, wherein the working medium a guided from the blade channel opening of the blade channels to the impeller side opening of the channel for the outflow of working fluid is guided intermediate region and wherein for the deflection of flowing through the intermediate region working fluid a guide body is provided, de r is extended from the intermediate region in the channel for the discharge of working medium.

Such a radial turbine is z. B. from the GB 492,144 A known.

The invention also relates to an energy conversion plant which makes use of a cyclic process for the provision of mechanical energy, in which a working medium is thermodynamically expanded almost isentropically by means of a thermal turbomachine (turbine).

A turbomachine designed as a radial turbine according to the prior art is in the Fig. 1 shown. The Fig. 1 is a sectional view of a portion of a conventional steam turbine in the form of a radial turbine, which is designed for a vapor flow below the speed of sound (subsonic flow). In a radial turbine, the corresponding working fluid flows in the radial direction with respect to a rotation axis an impeller and acts on the blade on the edge of this impeller. In axial turbines, however, the working medium is flowed in the axial direction with respect to a rotational axis of the impeller. When in the Fig. 1 shown turbine are formed by the radial in the axial direction at an angle of 90 ° extending blade inlet and -austrittskanten.

Trained as a radial turbine turbomachine the Fig. 1 has a substantially stationary turbine housing 110 in which a turbine wheel 120 (impeller) is arranged. The impeller 120 includes a plurality of (co-rotating) blades, wherein Fig. 1 representative of a blade 121 is shown. A gaseous working medium, for example exhaust gas from an internal combustion engine, flows through an inflow channel or through a nozzle channel 100 of the turbine housing 110 according to a directional arrow 151 and drives the impeller 120. For this purpose, the flowing working fluid is first accelerated in the nozzle channel 110 and deflected along a blade 121, wherein the edges of the blade are aligned on the one hand in the region of a working medium inlet parallel to the axis of rotation of the impeller 120 and have a working medium outlet 153 in the radial direction. The working medium is guided along its entire flow path in the impeller between vanes 121.

The impeller 120 of the flow device (turbine) according to Fig.1 is fundamentally similar to the impeller of a compressor designed in which the driven by the blades working fluid in an opposite to the representation according to Fig. 1 oriented direction flows. Accordingly, the flow can be deflected in an operating state as a compressor within the blades of the impeller from the inside out so that it runs after exiting the blade channels at Arbeitsmediumaustritt axially to the impeller. This type of paddle wheels or blading is well suited for working medium or vapor velocities below the speed of sound.

In radial turbines according to the prior art, with impellers in which the flow is deflected along its blading by 90 °, difficulties arise when steam flows reach their speed of sound.

A particular problem is that radial turbines for supersonic flows with parallel and axially aligned to the shaft blades cause vortex formation and thereby lose effectiveness.

It is therefore an object of the present invention to provide a radial turbine operable with supersonic flow, with which a higher efficiency and improved flow guidance is made possible.

Furthermore, it is an object of the present invention to provide a plant for energy conversion, in particular for carrying out a cyclic process, in particular a so-called Organic Rankine cycle process, whose efficiency is improved, in particular in the region of the expansion process contained.

The Organic Rankine cycle process (ORC) is a process of energy conversion in which a working fluid other than water vapor is used from a heat source to operate steam turbines. As a working medium mostly organic liquids with a lower evaporation temperature (T _verd <100 ° C), rarely used with a higher evaporation temperature. The method is used primarily in power generation and energy conversion plants when the available temperature gradient between the heat source and the heat sink is too low for the operation of a water vapor driven turbine.

This object is achieved on the one hand by a radial turbine having the features of patent claim 1 and on the other hand by a system having the features of patent claim 16.

Such a radial turbine according to the invention is in the German utility model application DE 20 2010 017 157.1 with the utility model DE 20 2010 017 157 U1 and the German patent application filed on 30.12.2010 DE 10 2010 056 557.1 to which reference is hereby made and the disclosures of which are fully incorporated into the description of this invention.

A radial turbine according to the invention has a housing with an inflow channel. In the housing, a rotatably mounted on a shaft impeller is arranged, which has a plurality of flowable by the working medium blades.

A special feature of a radial turbine according to the invention is that a guide body is provided with at least one deflecting element in the intermediate region between the Schaufelkanalaustritt and the outlet channel for a deflection of the effluent from a blade channel working medium in the direction of the outlet channel. Preferably, the working fluid first flows into the impeller via the inflow passage in the radial direction with respect to an axis of rotation of the impeller. The blades of the impeller thereby form a grid rotating with the impeller, divided in the circumferential direction of the impeller, in which the working medium is deflected in particular in the circumferential direction and directed in the radial direction into the interior of the impeller. Preferably, rectangular inlet openings of a plurality of blade channels are formed between the radially outer edges of the blades and rectangular outlet openings of a plurality of blade channels are formed between the radially inner edges of the blades. The inlet and outlet openings of a blade channel according to the invention are arranged in each case in planes which are parallel to each other or an acute angle to each other. More preferably, the (co-rotating) intermediate region according to the invention is arranged in the interior of the impeller such that it is surrounded in a ring shape at least in sections by the outlet openings of a plurality of vane channels.

The guide body preferably has a deflection element in the form of an integrally formed with the impeller shaft support structure with rotationshyperboloider or conical outer contour (impeller cone), which serves on its outer side for flow deflection. The guide body also has an annular deflection element in the form of a circular ring structure, which is at least partially inserted into the intermediate space. According to the invention, a guide body with all subsections can be connected in a rotationally fixed manner to the impeller. Alternatively, a baffle may have both stationary and non-moving baffles connected to the impeller.

With the arrangement of deflecting elements within the impeller, a detachment of the flow and an associated pressure loss is minimized immediately after the impeller according to the invention. The effect of an optionally downstream diffuser for additional efficiency increase is improved. This is achieved according to the invention particularly when at least one annular deflecting element separates the stream of working medium emerging from the outlet openings of a plurality of blade channels (blade channel outlets) into a plurality of separate partial streams. According to the invention, in particular in (with respect to the impeller) axial direction separate from each other partial streams, which can be performed differently by means of different contours on the front and back of a deflecting.

Furthermore, an engaging in the intermediate annular deflecting element can be fixed via a mounting ring on the housing of the radial turbine. The fastening ring is then preferred as a disk-shaped. flow-through lattice structure designed with radially extending spokes. In this case, the axial force acting on the paddle wheel resulting from the directional change of the flow is reduced.

In one embodiment of the invention, the working medium flows into the impeller via a widening inflow channel (in relation to the rotational axis of the impeller) in the radial direction. A constriction is provided for the flow of the working medium in the region of the inflow channel in order to be able to achieve supersonic speed in the area of the inflow channel.

According to one embodiment of the invention, the guide body has a deflecting element with a first and a second annular edge, wherein the first annular edge of the deflecting element is positioned adjacent to the Schaufelkanalaustritt and wherein the second annular edge is positioned adjacent to the diffuser channel entrance. As a result, an advantageous outflow of the working medium is achieved by the impeller. The consequence is that this prevents vortex formation in the outlet region of the flow device or in the diffuser inlet region.

In a further embodiment of the invention, the deflecting element is designed such that the first edge is a leading edge and in (relative to the impeller) radial direction, wherein the second edge is a trailing edge and facing in the same direction as the axis of rotation, so that so that the effluent from the blade channel working fluid is deflected from the radial to the axial direction. As a result, the efficiency of the turbomachine is improved. Preferably, the guide body has a plurality of spaced-apart deflection elements.

According to a further embodiment of the invention, the deflecting element comprises a side facing the impeller and a side facing away from the impeller. The deflecting element is here positioned so that it from the working medium can be flowed around on both sides. Accordingly arise on both sides of the deflecting annular channels for the working fluid. More preferably, the annular deflecting element is arranged approximately on all sides by working medium umströmbar. More preferably, the annular deflecting element at least partially on a drop, half-moon or wing wing-shaped cross-sectional geometry. This results in an advantageous deflection of the working medium in the region of the impeller. This enables a particularly efficient operation of the flow device.

In a further embodiment of the invention, the guide body on a plurality of spaced deflecting elements, which together form a through-flow grating with annular channels. Thus, the total flow of the working medium is divided into a plurality of annular partial streams. Within such a grid of deflecting the total current can be effectively deflected, the individual streams formed can be subjected to different treatments by the contours of the deflecting elements are designed differently from each other. In turn, further flow guidance elements such as turbulence promoters, surface coatings or the like can be arranged on the deflection elements. The same effect can basically be achieved even when using only one deflecting element.

In a further embodiment of the invention, the deflecting elements spaced apart from each other are positioned such that their edges facing the blades of the impeller have an axial spacing in the axial direction. At the same time, the edges facing the blades of the impeller at least approximately the same (outer) diameter, which in turn is smaller by a maximum of 10% than a (common) diameter of the inner edges of the impeller blades. Thus, a significant combination of emerging from the blade channels partial streams of the working medium is prevented. Rather, the in the circumferential direction of Impeller separated part streams in the baffle again divided (relative to the impeller) axial direction. This can of course be achieved even when using only one deflecting element.

In a further embodiment of the invention, the deflecting elements spaced from each other are positioned such that their edges pointing in the direction of the axis of rotation of the impeller have a different radial distance with respect to the axis of rotation of the impeller. Thus, different partial flows of the working medium are released with different radial distance in a downstream diffuser and minimized undesirable turbulence.

According to a further aspect of the invention, a plurality of permanent magnets and / or rotor windings are arranged on a shaft connected to the impeller, which with a plurality of adjacently arranged, the shaft encircling stator windings form an electrical generator. Accordingly, the turbomachine can be used as a "generator turbine" for power generation.

A radial turbine according to the invention can in particular be a thermal turbomachine. An idea of the invention is moreover to use a radial turbine according to the invention in an Organic Rankine cycle.

The invention therefore also extends to a system for converting energy with a cyclic process in which a turbomachine according to the invention is used. In particular, the invention relates to a radial turbine for a plant for the conversion of energy in the form of a so-called ORC plant. An ORC plant is a plant in which a thermodynamic cycle in the form of an "Organic Rankine Cycle" (ORC) is performed, with which heat can be converted into mechanical energy.

The heat supplied to an ORC system according to the invention can originate, for example, from a heat source in the form of an internal combustion engine from a combined heat and power plant, from a biomass combustion plant, from a geothermal source or from a solar power plant. Any form of waste heat can be used with an ORC system. For example, from the waste heat of internal combustion engines by means of an ORC system additional electrical energy can be obtained.

An ORC plant according to the invention may contain a condenser for liquefying a working medium of the plant, a pump, an evaporator for evaporating the working medium. In such a plant, there is a downstream of the evaporator radial turbine, in which the working fluid is expanded while removing kinetic energy from the circulation.

The pump brings a liquid working under standard conditions to operating pressure. Subsequently, the still liquid working medium flows through the heat exchanger (evaporator) or a heat exchanger system in which thermal energy is transferred for example from one of the aforementioned sources to the working medium of the ORC system. Due to the energy input, the working medium preferably evaporates completely. At the outlet of the evaporator then saturated steam or dry steam is formed. The energy input in the evaporator increases the specific volume and the temperature of the steam.

The vapor of the working medium is expanded almost isentropically to a lower pressure via a flow device according to the invention in the form of a turbine. The specific volume then increases due to the expansion in the turbine. This volume increase, caused by the pressure difference and the resulting work, is called volume change work referred to, which converts the turbine on their blades into mechanical energy.

If necessary, the steam flows out of the turbine through a regenerator in which a heat exchange takes place between the vaporous working medium and the liquid working medium coming from the pump (internal heat exchange).

The (still vaporous) working medium brought to the condensation temperature in the turbine and possibly in the regenerator reaches the downstream condenser, in which the working medium is reconstituted, indicating low-temperature heat. The heat released in the condensation is preferably fed via a cooling water circuit in a heat network. The working medium condenses out and returns completely to the liquid state of aggregation. The feed pump (pump) subsequently brings the working fluid to operating pressure and then back into the evaporator. This completes the cycle.

With a flow device according to the invention used as a turbine in an ORC system, in particular a generator can be driven, which generates electrical current with the turbine obtained from thermal energy mechanical energy.

Such an ORC system with a radial turbine according to the invention can be used both for small and large home systems as well as for large industrial plants and power plants. As home appliances are the power supplies, z. As air conditioning systems for offices, garages, hospitals and all types of buildings to understand. Industrial plants are, for example, production plants, in particular production plants of the automobile industry, in particular paint shops, in which a balanced demand for electricity (from mechanical energy) and heat at different temperature levels is needed.

Further advantages, features and details of the invention will become apparent from the following description of several preferred embodiments and from the drawings.

The features and feature combinations mentioned above in the description and the following features and feature combinations mentioned in the description of the figures and / or shown alone in the figures can be used not only in the respectively indicated combination but also in other combinations or in isolation, without the scope of To leave invention.

Advantageous embodiments of a radial turbine according to the invention are based on Fig. 2, Fig. 3, Fig. 4 , Fig. 5a and Fig. 5b described below.

Fig. 2

eine Schnittansicht einer Radialturbine für Überschallströmung mit einem Umlenkelement in Form eines Rotationshyperboloiden (Laufradkegel) zur Umlenkung der Strömung innerhalb des Laufrads;

Fig. 3

eine Schnittansicht eines Laufrads einer Radialturbine für Überschallströmung mit einem abschnittsweise in das Laufrad hineinragenden Leitkörper zur Verringerung der Wirbelbildung in einem nachgeschalteten Diffusor;

Fig. 4

eine Schnittansicht einer Strömungsvorrichtung mit hauptsächlich innerhalb des Laufrads liegenden Leitkörpern;

Fig. 5a

in einer vergrößerten Schnittansicht einen Abschnitt der Strömungsvorrichtung nach Fig. 4; und

Fig. 5b

eine Ansicht von Schaufeln des Laufrads der erfindungsgemäßen Strömungsvorrichtung aus Fig. 5a, die zur Verdeutlichung ihrer Geometrie quer zur Schaufelachse geschnitten gezeigt sind.

Show it:

Fig. 2

a sectional view of a radial turbine for supersonic flow with a deflection element in the form of a Rotationshyperboloiden (impeller cone) for deflecting the flow within the impeller;

Fig. 3

a sectional view of an impeller of a radial turbine for supersonic flow with a sectionally projecting into the impeller guide body to reduce the vortex formation in a downstream diffuser;

Fig. 4

a sectional view of a flow device with lying mainly within the impeller guide bodies;

Fig. 5a

in an enlarged sectional view of a portion of the flow device according to Fig. 4 ; and

Fig. 5b

a view of blades of the impeller of the flow device according to the invention from Fig. 5a , which are shown cut to illustrate their geometry transverse to the blade axis.

Fig. 2 shows in sections a sectional view of a turbomachine in the form of a radial turbine with a substantially stationary turbine housing 1, 4, 11, in which a turbine wheel 2 (impeller) is arranged. The turbine housing 1, 4, 11 in particular comprises a nozzle ring 1 and an associated cover 11. The cover 11 and the nozzle ring 1 are preferably designed as separate assemblies. Between them, the nozzle channels 10 are formed. The turbine housing 1, 4, 11 comprises a diffuser 4 with an outlet channel 40 for the working medium.

The impeller 2 disposed in the turbine housing includes a plurality of (co-rotating) vanes. In the Fig. 2 the impeller 2 is shown with a blade 21. Between the blades of the impeller 2 straight or curved blade channels 20 are formed, which have a substantially rectangular cross-section. The blades are connected to each other via a base of the impeller 2 and on a side spaced therefrom via a so-called bandage 22.

A vaporous working medium, for example the working medium of an ORC system, flows through a nozzle channel 10 of the turbine housing 11 acting as an inflow channel according to a directional arrow 51. In the inflow channel 10, the flowing working medium is accelerated via a corresponding nozzle geometry, so that sound velocity is reached at a constriction. wherein the working fluid can be brought to supersonic speed before a transfer into the impeller 2.

The vaporous working medium flows out of the nozzle channel 10 and impinges on the blade 21, which is designed such that both the flowed Edge and the lying in the direction of flow edge of the blade 21 and thus also these are aligned parallel to and parallel to the impeller shaft. The majority of the stream 51 of working medium is deflected after passing through the blades 21 or a respective blade channel between a plurality of blades 21 (and thus in a so-called intermediate region of the impeller 2) to parallel to the axis of rotation of the impeller (arrow 53). For this purpose, a guide body 3 in the form of a conical deflecting element (impeller cone) is provided according to the invention, which is preferably designed as a rotational hyperboloid. This deflecting element can optionally be designed in one piece with the impeller. The guide body 3 is located in an intermediate region 29 between the Schaufelkanalaustritten 23 and the inlet opening 24 in the outlet channel 40 formed by the diffuser 4. The trained as impeller cone deflection element with the guide body 3 is in the region of its base in the intermediate region 29 within the impeller. 2 arranged. It is partially surrounded annularly by the blade channel exits 23 and the blades 21 of the impeller. The guide body 3 extends into the outlet channel 40 formed by the diffuser 4.

The impeller cone causes a largely laminar flow deflection at moderate flow velocities. At high flow velocities, vortices 54 can arise.

To reduce the in Fig. 2 represented vortex formation can be achieved by the positioning of guide bodies in the outflow or in the diffuser 4 behind the impeller 2, a reduction of vortex formation.

A radial turbine according to the invention is in the Fig. 3 shown substantially similar to the radial turbine according to Fig. 2 is executed. Accordingly, to the above description Fig. 2 Be referred. Corresponding are also similar components and functional units provided with the same reference numerals. The radial turbine after Fig. 3 comprises, in addition to a first deflection element in the form of the co-rotating impeller cone, a second deflection element 31 in the form of an annular guide body 3 'mounted on the housing side. The guide body 3 'preferably engages in an intermediate region 29 of the impeller 2, which is encompassed by the impeller blades 21. As a result, the stream of working medium emerging from the impeller blade channels can be split up early into two annular partial streams.

The guide body 3 'has a first and a second annular edge 25, 26. The first edge 25 of the deflection element is positioned adjacent to the blade channel exit 23 within the intermediate region 29. The second edge 26 is arranged adjacent to the inlet opening 24 within the outlet channel 40. The first edge 25 acts as a leading edge. The second edge 26 is a trailing edge. The deflecting element 31 is formed with a guide contour 28, which extends from the first edge 25 from an approximately to a rotational axis 27 of the impeller 2 radial direction to the second edge 26 in an approximately to the axis of rotation 27 of the impeller 2 axial direction. The effluent from the blade channel 20 working fluid is thus deflected by the deflecting element 31 from a substantially radial in a substantially axial direction. In modified embodiments, other flow directions can be generated by the contours of the deflecting elements are oriented in the corresponding directions.

If residual vortices 54 occur in spite of the measures described-for example, at particularly high flow velocities, further or further improvements may be provided according to the invention as an alternative or in addition.

In particular, radial turbines are often used in ORC plants for converting the flow energy of the working medium into a torque. Due to the low speed of sound in such media and the high pressure ratios between the inlet and outlet of the steam in the turbine, the flow rate of the steam in the impeller of the turbine is often above the speed of sound. Also, the exit velocity of the steam from the impeller is often still over Mach 0.7. Considering the geometrically predetermined large difference between the radius of curvature of the impeller cone and the inner edge of a drum 22 over the blades 21 and the high outflow velocity, a uniform outflow of the vaporous working medium in turbines of ORC systems is often prevented.

In the Fig. 4 . 5a and 5b are sections of a further inventive, designed as a radial turbine turbomachine shown, the nozzle ring 1 with a nozzle cover 11, mounted in a housing on a shaft impeller 2, an inflow passage 10, a diffuser 4, a plurality of arranged on the impeller 2 blades 21, a first has a lattice-shaped guide body 3 "and a second conical guide body 3. A basic mode of operation corresponds to that of the radial turbine according to FIG Fig. 2 respectively. Fig. 3 , so that reference can be made to the statements made for this purpose.

A vaporous working medium can be conducted via the inflow passage 10 to a wheel entry of the impeller according to a directional arrow 51. It meets there the blade 21 and flows between the blades 21 in a blade channel 20 according to a directional arrow 42 ( Fig. 5b ). After flowing through the blade channel 20, the working fluid enters an intermediate region 29 between a blade channel outlet and an outlet channel 40 downstream of the rotor 2 Diffuser channel entry according to the invention, the first guide body 3 "and the second guide body 3 is positioned, wherein both guide body preferably also sections can protrude out of the intermediate region in the outlet channel 40.

According to the Fig. 5a the first guide body 3 "comprises, in addition to a lattice-shaped fastening ring 34, which is also provided with radial spokes, two annular deflection elements 31 and 32, wherein in alternative embodiments more than two deflection elements can be used circular deflecting elements 31, 32 are preferably made in one piece together with the fastening ring 34 and thus form the first guide body 3 ", which may also be referred to as a flow grid. The first guide body 3 "thus constructed cooperates with the second guide body 3 in the form of the impeller cone: both guide bodies 3, 3" cooperatively divide the intermediate region 29 of the impeller 2 at least in sections into annular flow channels separated from one another.

The working medium is accordingly divided several times immediately after the blades 21 by the deflecting elements 31 and 32 of the first guide body 3 "and, for the most part, still directed within the paddle wheel 2 parallel to its axis of rotation according to a directional arrow 53.

The first baffle 3 "extends between a first 25 and a second edge 26 of a baffle 31 and 32, respectively, and is configured such that the first edge is positioned adjacent the airfoil exit, with the second edge 26 positioned adjacent to the diffuser channel entrance 40.

The deflecting element 31, 32 is designed such that the first edge 25 serves as leading edge and points in the radial direction to the axis of rotation of the impeller 2, wherein the second edge 26 is a trailing edge and in the same Direction as the axis of rotation points, so that the effluent from the blade channel 20 working fluid is deflected from a radial in an approximately axial direction. In this case, both deflecting elements 31, 32 each have a side facing the impeller 2 and a side facing away from the impeller 2. The deflection elements 31, 32 are in particular positioned such that they can be flowed around on both sides by the working medium.

As a result, the working medium after its exit from the blade channel 20 is deflected in such a way in the diffuser channel 40 that a flow along the impeller 2 is optimized.

The deflecting elements 31 and 32 of the first guide body 3 "preferably have crescent-shaped cross-sectional contours, the profile of which is designed to be favorable in flow.) The first edge (annular leading edge) facing the impeller 2 points radially away from the center The second edge located on the axial opposite side (annular Trailing edge) points away from the impeller base 2. The curvature of the profile of the deflecting elements is designed such that the working medium is continuously deflected parallel to the axis of rotation of the impeller 2.

If a plurality of annular deflecting elements 31, 32 are used in the guide body 3 ", then the trailing edges of these deflecting elements 31, 32 have different diameters with respect to the axis of rotation of the impeller 2, while it is expedient that the leading edges have the same diameter with respect to a rotational axis of the impeller 2 Preferably, the leading edges are positioned as close as possible to the exit edges of the blades 21. For this purpose, it makes sense that the (substantially the same) diameter of the leading edges of the deflecting elements 31, 32 have a diameter which is less than 10% smaller than the diameter of the circle that all the exit edges of the blades touch.

According to Fig. 5a Each blade 21 has a blade height 60 at the blade channel outlet within the rotor 2. A first axial distance 61 between a surface of the impeller base and the leading edge of the (first) deflecting element 31 is smaller than an axial distance between the leading edge of the (second) deflecting element 32 and the same surface of the impeller base, so that between the leading edges of both deflecting elements 31, 32 an axial distance 62 is present. In addition, the leading edge of the deflecting element 32 to the drum 22 is spaced by an axial distance 63.

Furthermore, the mutually adjacent deflection elements 31,32 are positioned such that their trailing edges 26 have a different radial distance with respect to the axis of rotation of the impeller 2. In addition, the leading edges facing the blades of the impeller have a different axial spacing 61 or spacing 61 + 62 relative to the impeller base in the axial direction.

The impeller 2 is the rotating part of the turbomachine or the radial turbine, which extracts work from the flowing working medium when using the turbomachine as a turbine. The impeller 2 is connected to a shaft, not shown, is discharged through the generated mechanical energy.

In the guide body 3 downstream diffuser 4 is slowed by expansion of the flow cross section, the gas flow and increases the static gas pressure. The diffuser 4 represents in principle the inversion of a nozzle.

An in Fig. 5a shown bandage 22 is disposed on the blades 21 and serves to stabilize the impeller 2 and to keep in shape.

The guide body 3 and the deflecting elements 31 and 32 are preferably connected via webs 33 to the turbine housing or the diffuser 4 of the turbine connected, so that the forces acting due to the deflection of the working medium forces are not transmitted to the impeller shaft. The guide body 3 is the counterpart to the moving impeller 2, wherein the guide body 3 is preferably formed fixedly to the housing or on the diffuser 4 via the webs 33. Accordingly, the impeller 2 and the guide body 3 together form a step. For fixing the deflecting elements on the diffuser 4, a fastening ring 34 of the guide body 3 is provided on the diffuser inlet.

It is also possible to attach the deflecting elements 31 and 32 to the impeller 2, so that they then co-rotate. Alternatively, a deflecting element may be fixed to the impeller and another to the housing.

The guide body 3 "or the deflecting elements 31 and 32 in a turbomachine according to the invention are manufactured from (noble) steel and are produced by machining processes, but these can in principle also be produced from cast metal (cast aluminum, cast steel, cast iron).

The turbomachine is preferably used as a radial turbine in an ORC plant for carrying out an Organic Rankine cycle.

For the purposes of the present invention, a turbine system, in particular, in which a vaporous working medium flows under a pressure, is expanded and accelerated in a fixed nozzle system, even with guide blading, is designated in particular as turbomachine. After the nozzle system, the steam is deflected therein by a rotating blade system, possibly further relaxed and gives off its flow energy through the blades to a shaft connected to the blades or coupled. From this shaft, the mechanical rotational energy is then transferred to a consumer or a means for converting energy for further use. For example, you can powered by the shaft facilities for converting energy in the form of generators for power generation.

The invention causes with simple and inexpensive Leitkörper an increase in efficiency of radial turbines. With a turbomachine according to the invention, the efficiency of an ORC system can thus be improved.

LIST OF REFERENCE NUMBERS

1

nozzle ring

1,4,11

turbine housing

2

Wheel

3, 3 ', 3 "

conducting body

4

diffuser

5

flow direction

6

distances

10

nozzle channel

10

inflow passage

11

Cover of the nozzles

20

blade channel

21

shovel

22

Bandage on shovel

23

blade outlet

24

inlet opening

25

edge

26

edge

27

axis of rotation

28

guide contour

29

Intermediate area within the impeller

30

Channel between the guide bodies

31.32

deflecting

33

Connecting web between the guide bodies and the attachment

33

web

34

Mounting ring of the guide body at the diffuser inlet

40

Channel in the diffuser

40

outlet channel

40

Diffuser duct inlet

40

diffuser channel

42

Flow between the blades of the impeller

42.51

arrow

51

electricity

51

Flow in the nozzle channel

52

Flow in the blade channel

53

Flow between the guide bodies

53

arrow

54

whirl

54

Flow separation in the diffuser

60

Blade height at the blade channel exit of the impeller

61,62,63

Axial distance

61

Axial distance between impeller disc and deflector

62

Axial distance between both deflection elements

63

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

100

nozzle channel

110

turbine housing

120

Turbine wheel, impeller

121

shovel

151

arrow

153

Working medium outlet

Claims (16)

1. Radial turbine having a housing (1, 4, 11) which has a housing duct (10) for the inflowing of working medium and comprises a diffusor (4) having a duct (40) for the outflowing of working medium, wherein in the housing (1, 4, 11) there is positioned an impeller (2) mounted on an impeller shaft which is able to rotate about a rotation axis (27), there being arranged on the impeller multiple blades (21) which form blade ducts (20) which have a blade duct opening (23), oriented towards the rotation axis (27), for the through-flowing of working medium to the duct (40) for the outflowing of working medium, wherein the duct (40) for the outflowing of working medium has an impeller-side opening (24), wherein the working medium is guided through an intermediate region (29) extending from the blade duct opening (23) of the blade ducts (20) to the impeller-side opening (24) of the duct (40) for the outflowing of working medium, and wherein there is provided, for redirecting working medium flowing through the intermediate region (29), a guiding body (3', 3'') which extends from the intermediate region (29) into the duct (40) for the outflowing of working medium, characterized in that
   the housing duct (10) for the inflowing of working medium has a throat and is widened on the impeller side so that the introduced working medium can reach supersonic speeds, and the guiding body (3', 3") is arranged coaxially with the rotation axis (27) of the impeller (2) and has at least one annular redirection element (31, 32), arranged coaxially with the rotation axis (27) of the impeller (2), with a sharp annular leading edge (25) arranged in the intermediate region (29) and with a sharp annular trailing edge (26) arranged in the duct (40) for the outflowing of working medium, wherein working medium can flow either side of the redirection element (31, 32), on a side facing the rotation axis (27) and a side facing away from the rotation axis (27).
2. Radial turbine according to Claim 1, characterized in that the guiding body (3', 3") is secured on the housing (1, 4, 11).
3. Radial turbine according to Claim 1 or 2, characterized in that the impeller (2) has, for redirecting working medium, an impeller cone (3) that projects into the guiding body (3', 3'').
4. Radial turbine according to Claim 3, characterized in that the impeller cone (3) is in the form of a hyperboloid of revolution.
5. Radial turbine according to one of Claims 1 to 4, characterized in that the duct (40) for the outflowing of working medium is widened on the side facing away from the impeller (2) in the manner of a diffusor.
6. Radial turbine according to one of Claims 1 to 5, characterized in that the working medium flows on the impeller (2) via the housing duct (10) in the radial direction towards the rotation axis (27) of the impeller (2).
7. Radial turbine according to one of Claims 1 to 6, characterized in that the leading edge (25) of the redirection element (31, 32) is positioned adjacent to the opening (23) of the blade ducts (20), and the trailing edge (26) is arranged adjacent to the impeller-side opening (24) of the duct (40) for the outflowing of working medium.
8. Radial turbine according to one of Claims 1 to 7, characterized in that the redirection element (31, 32) has a guiding contour (28) that extends from the leading edge (25), from a direction radial to a rotation axis (27) of the impeller (2), to the trailing edge (26), in a direction axial to the rotation axis (27) of the impeller (2), in order to redirect, from the radial direction into the axial direction, working medium flowing from one of the blade ducts (20) to the duct (40) for the outflowing of working medium.
9. Radial turbine according to one of Claims 1 to 8, characterized in that the guiding body (3'') has multiple redirection elements (31, 32) which are spaced apart from one another, which each have a leading edge (25) and a trailing edge (26), and which together form a through-flowable cascade in which the total flow of the working medium is split into multiple annular part flows.
10. Radial turbine according to Claim 9, characterized in that at least one redirection element (31, 32) has a crescent-shaped cross-sectional geometry.
11. Radial turbine according to Claim 9 or 10, characterized in that the mutually spaced-apart redirection elements (31, 32) are positioned such that their leading edges (25) oriented towards the blades (21) of the impeller (2) have an axial spacing (62) in the axial direction.
12. Radial turbine according to one of Claims 9 to 11, characterized in that the mutually spaced-apart redirection elements (31, 32) are positioned such that their trailing edges (26) have a different radial spacing with respect to the rotation axis (27) of the impeller (2).
13. Radial turbine according to Claim 12, characterized in that the radial spacing of the leading edges (25) from the rotation axis (27) of the impeller (2) is greater than the radial spacing of the trailing edges (26) from the rotation axis (27) of the impeller (2).
14. Radial turbine according to one of Claims 1 to 13, characterized in that on a shaft connected to the impeller (2) there are arranged multiple permanent magnets and/or rotor windings which, together with multiple stator windings arranged adjacently and surrounding the shaft, form an electric generator.
15. Use of a radial turbine formed according to one of Claims 1 to 14 in an organic Rankine cycle.
16. Plant for carrying out an organic Rankine cycle, having a condenser for liquefying a working medium circulated in the plant, a pump, an evaporator for evaporating the working medium and a radial turbine connected downstream of the evaporator, in particular a turbine in which the working medium is expanded, thereby extracting energy from the circuit, wherein the radial turbine is designed according to one of Claims 1 to 14.

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