EP1452688A1 - Steam turbine rotor, method and use of actively cooling such a rotor - Google Patents

Abstract

An axially-extended vapor turbine rotor (31) comprises an outer boundary enclosing a space (35) receiving the main flow (36) of the fluid working medium with an external position (30a) holding a first blade (41a). An integrated channel (46a,b) extends between a region before the first position (30a) and a second region (30b). An independent claim is also included for an active cooling process for the turbine above.

Description

The invention relates to a steam turbine rotor extends along an axial extent, comprising: a Outside, which borders on an outside space that is for recording a main flow of a fluid working medium is provided and a first digit along the outside where a first row of blades is held. The invention relates also a steam turbine. The invention further relates to Process for active cooling of a steam turbine rotor Art.

When hot steam is applied to a steam turbine as a working medium one strives to increase the achievable Steam temperatures of highly stressed components to cool. As far as possible, this includes shielding and heat dissipation through an appropriately dimensioned Cooling. Under a steam turbine in the sense of the present Registration is understood every turbine or partial turbine, which flows through a working medium in the form of steam becomes. In contrast, gas turbines with gas and / or air flows as a working medium, but completely different temperature and pressure conditions than the steam in a steam turbine. In contrast to gas turbines has in steam turbines z. B. that flows into a sub-turbine Working medium with the highest temperature at the same time the highest pressure. There is an open cooling system So not without the supply of a cooling medium outside the turbine realizable. Cooling measures like those of gas turbines are therefore known to be of gas turbines known and only suitable for gas turbines as not transferable to steam turbines.

Under a housing of a steam turbine is in particular that stationary housing component of a steam turbine or a partial turbine to understand that along the axial extent of the Steam turbine has an interior that allows for flow with the working medium steam is provided. This can, depending by steam turbine type, an inner casing and / or a Guide vane carrier. Is under a steam turbine casing also to understand a turbine housing, which is not an inner housing or has no vane carrier.

In the interior there is a along the axial extent Bladed rotor arranged so that at Flow through the interior with heated and under pressure standing steam the rotor over the blades through the steam is rotated. The blades of the rotor will be also known as blades. A steam turbine points also stationary guide vanes, which in the Grab intermediate spaces of the rotor blades and through the inner housing / Guide blade carriers are held. A blade is usually along an outside of one Steam turbine rotor held. It is common Part of a blade ring, which is a number of blades includes that along an outer circumference on the outside of the steam turbine rotor are arranged. It points each blade with its blade radially outwards. A blade ring is also referred to as a row of blades. Typically there are a number of rows of blades connected in series. According to one second place along the axial extent behind the first Place another second blade ring along the Held outside of the steam turbine rotor.

In the previously known cooling methods, especially for one Steam turbine rotor, is between active cooling and distinguish between passive cooling. With an active Cooling is cooling by a steam turbine rotor separately, d. H. cooling medium supplied in addition to the working medium causes. In contrast, passive cooling only takes place through suitable guidance or use of the working medium in the mainstream. A usual cooling one Steam turbine rotors are limited to passive cooling.

However, from US 6,102,654 and WO 97/49901 it is known a rotor of a steam turbine with cool, already expanded To flow through steam. Coolant is thereby an essentially central cavity along an inner one Guided rotor wall and then from there via separate radial Branch channels to the outside, especially in areas to be cooled of the housing. Because the central Cavity and the branch channels at the point of the highest component load are arranged, this leads to a considerable Strength disadvantage for the rotor. This also has the Disadvantage that there is a temperature difference across the rotor wall must remain limited, otherwise a too large one Thermally deform the rotor temperature difference too much would. For these reasons, such a concept has so far been used have not yet been widely used. With a flow heat is removed from the rotor, however the heat is removed relatively far from the Place of heat supply. A heat dissipation in the immediate So far, the proximity of the heat supply has not been sufficient been realized.

A further, passive cooling can be done using a suitable Management and use of the expansion of the vapor of the working medium can be achieved. This is that of a steam turbine incoming steam through exclusively stationary parts, z. B. a vane ring or radially acting vanes first expands before it impacts rotating components. The steam cools down in the area of about 10 K. However, only one can be said about this achieve limited cooling effect on the rotor.

In US 6,102,654 an active cooling of a steam turbine rotor realized only to a very limited extent and the cooling is also on the inflow area of the hot working medium. As in FIG 1 of this application reproduced, is according to US 6,102,654 cooling medium through the housing onto a protective shield and onto a first one Guide vane ring directed to a temperature stress to reduce the rotor and the first guide vane ring. Part of the cooling medium is mixed with the working medium. Apart from the limitation of cooling to the inflow area Cooling should only be caused by an inflow of air components to be cooled. The one that can be achieved Cooling effect on the rotor is limited as it turns limited to the inflow area of the main flow.

A single guide vane ring is known from WO 97/49901 selectively through one of a central cavity fed to cool separate radial channel in the rotor. To cooling medium is mixed into the working medium via the duct and the guide vane ring to be cooled selectively by cooling medium incident flow. The cooling effect on the rotor is included improvement. In addition, the hole causes disadvantageously a significant increase in the voltage of the rotor compared to the design without a hole.

In EP 1154123 there is a possibility of removal and guidance a cooling medium from other areas of a steam system and the supply of the cooling medium in the inflow area of the working medium described.

To achieve higher efficiencies in power generation with fossil fuels there is a need to increase Steam parameters, d. H. higher pressures and temperatures than before usual to use. Steam is the working medium Pressures above 250 bar and temperatures above 540 C are provided. Such steam parameters are in the article in detail "New steam turbine concepts for higher entry parameters and longer end blades "by H. G. Neft and G. Franconville in the magazine VGB Kraftwerkstechnik, No. 73 (1993), No. 5, specified. The disclosure content of the article is hereby included in the description of this application. In particular are examples of higher steam parameters in Figure 13 of the article called. The article mentioned is for improvement the cooling of a steam turbine rotor a cooling steam supply and passing the cooling steam through the first guide vane stage and possibly also through the second guide vane stage proposed. This is an active cooling provided only for the steam turbine housing. moreover is cooling on the main flow area of the working medium limited and in need of improvement.

All previously known cooling processes for a steam turbine rotor So see as far as it is active cooling processes at all acts, at most a targeted inflow of a separate and to be cooled turbine part and are on limits the inflow range of the working medium. This can when loading conventional steam turbines with higher steam parameters to an elevated one that acts on the entire turbine cause thermal stress, which is described by a The usual cooling of the rotor is insufficiently degraded could be. Steam turbines to achieve higher Efficiencies, for example, work with higher steam parameters, need improved cooling, especially the Rotor to a higher thermal load on the steam turbine to dismantle to a sufficient extent. The problem is that the increasing when using conventional turbine materials Stress on the rotor due to increased steam parameters to an adverse thermal load on the rotor and lead to an inadmissible temperature increase can.

It is therefore an object of the present invention to provide a device and to provide a method and use that adequate cooling of a steam turbine rotor, in particular when operating a steam turbine with increased steam parameters and usual turbine materials.

This object is achieved by the invention using an input mentioned steam turbine rotor solved, in which at least one integrated implementation is provided, which is at least between a first placed in front of the first Area and one located behind the first digit second area extends continuously.

The invention is based on the consideration that to provide sufficient cooling of a steam turbine rotor one over the inflow area of the working medium and one via the only separate cooling of the first blade stage active cooling beyond that within a steam turbine rotor should be provided. The knowledge of the invention is that this is with a consistent in the rotor integrated implementation can be achieved, at least goes beyond a blade stage. This creates the Possibility of active cooling of a substantial or whole Part of the rotor receiving the blades. The part at least goes beyond the inflow area and at least goes beyond a blade level. Advantageously extends the part extends over at least two blade levels, conveniently over several stages of barrel blading. In order to the possibility is created of using a cooling fluid of a coherent feed-through system integrated in the rotor to run consistently.

This has the main advantage that cooling one Steam turbine rotor not only via at least one, advantageous over several blade levels, at least between a first area arranged in front of the first position and a second area located behind the first position takes place continuously, but also has the advantage that the Heat dissipation in the immediate vicinity of the heat supply, namely in near its surface. In this way the Cooling in conventional steam turbines improved, so this could be manufactured with lower material costs. Of The proposed cooling concept also allows the design new steam turbine concepts for higher entry parameters, especially with the highest steam parameters like them for example at temperatures above 500 C. Examples of this can be found in the article mentioned above "New steam turbine concepts for higher entry parameters and longer end blades "by H. G. Neft and G. Franconville. Exemplary steam parameters of steam as a working medium are, for example, 250 bar and 545 C or 300 bar and 600 C.

Advantageous developments of the invention are the subclaims to remove the steam turbine rotor and give in Individual advantageous ways to the proposed Rotor regarding the mentioned and other advantages in To train individuals.

A particularly preferred further development sees a second Imagine along the outside at the second row of blades is held, along the axial extent the second digit is located behind the first digit and the implementation being at least between one before first position arranged first area and one behind the second area arranged throughout extends. It could also be between the first digit and the a number of further positions are provided for the second position be in which a row of blades is held. In particular the at least one implementation is more advantageous Wise part of a coherent implementation system, that extends along the axial extent of the steam turbine rotor extends. This creates the possibility of cooling steam to run parallel to the main flow. Cooling several Blade stages are as far as possible along the entire rotor allows. Depending on requirements and needs, one could Implementation system can be designed flexibly. The least an implementation could conveniently be between one in front of the first blade ring arranged first area and a second one arranged behind the last blade ring Extend area continuously. An implementation system could, however, also be made up of subsystems. It could additionally or alternatively, a first number of implementations be provided, each consistently via a one or more blade stages along the axial extent go out. This could be done via another second Bushings to be connected to a bushing system, which are aligned radially or in any other way. The least one implementation or the first number of implementations are advantageously arranged close to the surface. The further second bushings could also be in the rotor run or lead out of the rotor surface.

An open cooling system is advantageously provided, which the Possibility of adjusting the parameters of the cooling medium provides the parameters of the working medium. This will be in detail explained below using the proposed method.

In contrast to the working medium in gas turbines Steam turbines the inflowing working medium with the highest Temperature at the same time the highest pressure. conveniently, is therefore the minimum for a steam turbine rotor an implementation part of a coherent implementation system, that has an external feed that is for the inflow of cooling medium is provided. This creates the possibility of using the cooling medium at least slightly supply higher pressure than the working medium for the implementation. This can advantageously be achieved in that the cooling medium is higher in the water-steam cycle Taken pressure and sufficiently low temperature becomes.

In the following, further advantageous configurations of a Implementation system described, the part of which at least an implementation according to the proposed concept is. Such an implementation system is advantageously close to the surface arranged to the outside of the steam turbine rotor. In this context, near-surface means in particular that the implementation system, especially the at least one Implementation, in a range of radial expansion Steam turbine rotor is arranged, which through the outside of the rotor on the one hand and the internal radial expansion a blade groove on the other hand is limited. The at least one implementation and / or any other Implementation of the implementation system can be done as needed advantageously as a channel or as any Kind of cavity inside the rotor, preferably in its near-surface area. this makes possible a further improvement in heat dissipation at the site of the Heat input. The proposed cooling concept within of the steam turbine rotor mentioned is thus more effective as one near a central cavity on the inside the rotor wall adjacent to the axis for the Cooling attacking rotor. There are also advantages with regard to the deformation behavior of a steam turbine rotor. The cooling according to the proposed concept is reinforced also the benefits of thermal insulation layers on the rotor and shovels. Such layers have a comparative low thermal conductivity and can under provided that there is an adequate heat sink is to build up a high temperature difference. In order to can rotor, blade feet and sometimes also blades are kept at a much lower temperature than without an insulation layer. As an alternative to an insulation layer or in combination with such, can Use of the proposed cooling concept, the application of less well conductive blade materials makes sense his. A preferred example of this are, for example austenitic materials.

A coherent implementation system expediently points one along a circumferential extension of the rotor at least partially circumferential channel. Together with the allows at least one axially extending implementation this is an overall cooling of the steam turbine rotor, preferably near its outside.

The parameters of the cooling medium are advantageous depending the parameters of the working medium via an open cooling system gradually adjusted. Conveniently, the first area has a first opening to the main flow. Advantageous the second area also has a second opening to the main flow. This will cool several Blade levels allows, the cooling medium each one the main flow has similar pressure, so advantageous the aim is to minimize the differential pressure load is.

The at least one implementation could be a hole, groove or be integrated in any other suitable way. Furthermore it turns out to be especially cheap if the outside of the rotor is formed by a circumferential shielding plate is. This enables the steam turbine rotor to be cooled Blading area favorably completely against the main flow is shielded. This has major advantages with regard to oxidation of the rotor material. On circumferential shielding plate could conveniently by a Row of blades, especially held by the blade feet his.

The at least one implementation can be done as needed To run. So it turns out to be convenient if the implementation through a shovel, in particular through a shovel foot, is led. There could be a groove on a blade root be part of the implementation. If need be, too a bore through a single blade root or, alternatively or in addition, by two adjacent blade feet part the implementation. It also proves to be cheap to provide a channel in an airfoil that matches the Implementation is connected. In this way is an advantageous cooling of the blade area z. B. possible via film cooling.

The invention also leads to a steam turbine with a Steam turbine rotor according to the concept proposed above or a training course.

With regard to the method, the object is achieved by the invention with a method for active cooling of a steam turbine rotor solved the type mentioned in the invention is provided along a fluid cooling medium the axial extent at least between one before the first Positioned first area and one behind the first area arranged second area consistently to lead.

According to a development of the invention, it is provided that the steam turbine rotor a second place along the outside has held a second row of blades is, the second digit along the axial extent is arranged behind the first position and wherein the fluid Cooling medium at least between one before the first position arranged first area and one behind the second Position arranged second area is guided continuously. It proves to be particularly advantageous that the Coolant in a coherent duct system along the axial extent over the first digit and the second digit and over a number of intermediate, other places, each with a row of blades is led.

Since the working medium flowing into a steam turbine with the highest temperature also has the highest pressure, it is particularly favorable that the cooling medium Steam turbine rotor is supplied externally. Advantageous The pressure of the cooling medium exceeds a pressure of Working medium in the main flow.

It turns out to be particularly favorable that the cooling medium with a pressure that is dependent on a Pressure of the main flow is adjusted and in particular the Coolant flow is throttled. This training enables the formation of an adapted to higher steam parameters, open cooling system. Throttling the cooling medium to adapt the pressure to the main flow takes place advantageously Gradual design through appropriate designs the at least one implementation, preferably in Connection with openings to the main flow.

Furthermore, the cooling medium is advantageously at a temperature and / or supplied in an amount that is dependent is adapted to a temperature of the main flow. This can advantageous due to security requirements sufficient valve to regulate the quick-closing and control processes of the turbine valves. The temperature of the cooling medium is according to safety-related Determine requirements advantageously and technically to monitor. If necessary, a disproportionate amount of cooling medium in the feedthrough system be introduced so that the temperature of the main flow after the cooled blading area by reinforced Admixture of cooling medium kept sufficiently low becomes.

If the cooling medium fails, the turbine can be operated if necessary with the help of a number of turbine valves interrupted, which is referred to as a quick close.

The concept of supplying the cooling medium explained above and the line of the cooling medium in a rotor-integrated, Advantageous near-surface feedthrough system can be used accordingly be designed and adapted to the requirements.

The proposed concept can also, according to a variant of the invention, for starting and / or for rapid cooling one Turbine can be used.

The rotor is in a particularly advantageous embodiment and / or the turbine blades with a heat insulation coating Mistake. Such heat insulation layers have usually a comparatively low coefficient of thermal conductivity on and can, provided that locally a suitable heat sink is provided, a high one Build up temperature difference. The function of this heat sink can be taken over by the cooling system provided here so that the rotor designed in this way for the Use of heat insulation layers particularly suitable is. It can rotor, blade feet and possibly also Shovel blades at a much lower temperature are kept as without such insulation layers. alternative to or in combination with the use of insulation layers can also use it comparatively poorly heat-conductive blade materials such as austenitic materials can be provided.

Embodiments of the invention are now described below the drawing compared to the prior art, which is also shown. This is said Not necessarily show exemplary embodiments to scale, rather, the drawing, where useful for explanation, executed in a schematic and / or slightly distorted form. With regard to additions from the drawing immediately recognizable teachings are based on the relevant State of the art referenced. It must be taken into account that regarding various modifications and changes Form and detail of an embodiment can be made without deviating from the general idea of the invention.

The in the description above, in the drawing as well features of the invention disclosed in the claims both individually and in any combination for the Embodiment of the invention be essential. The general Idea of the invention is not limited to the exact form or the detail of those shown and described below preferred embodiment or limited to one Subject that would be limited compared to that in the Subject claimed.

The preferred embodiment of the invention is related described with a cooling system that has a pressure-adjusted Cooling steam mass flow provides the rotating Components, i.e. the rotor and the blades, targeted can cool. Thus, the preferred one proposed here Embodiment makes a significant contribution to cost-effective, industrial feasibility higher Achieve steam parameters and higher efficiencies. About that In addition, one described here or different and modified embodiment of the invention also used are used to make more cost-effective rotor and blade materials current steam parameters.

FIG 1

ein bekanntes Kühlkonzept bei einem Dampfturbinenrotor, das auf die Kühlung im Einströmbereich des Arbeitsmediums beschränkt ist;

FIG 2

eine schematisierte Darstellung eines Kühlungskonzepts bei einem Dampfturbinenrotor gemäß einer bevorzugten Ausführungsform;

FIG 3

eine Darstellung der Zuführung des Kühlmediums und der Leitung des Kühlmediums in einem rotorintegrierten, oberflächennahen Kanalsystem im Beschaufelungsbereich bei der bevorzugten Ausführungsform;

FIG 4

eine Detaildarstellung entlang des Schnitts A-A bei dem Kanalsystem der FIG 3;

FIG 5

eine Detaildarstellung entlang des Schnitts B-B bei dem Kanalsystem der FIG 3;

FIG 6

eine Detaildarstellung entlang des Schnitts B-B bei einer abgewandelten Gestaltung des Kanalsystems der FIG 3;

FIG 7

eine schematisierte Darstellung einer Übertragungsmöglichkeit des Kühlmediums in den Bereich der Laufschaufelbefestigung gemäß der bevorzugten Ausführungsform;

FIG 8

eine Darstellung einer weiteren Übertragungsmöglichkeit des Kühlmediums in den Bereich der Laufschaufelbefestigung gemäß der bevorzugten Ausführungsform;

FIG 9

eine Darstellung einer weiteren Gestaltungsmöglichkeit des Kanalsystems zur Leitung des Kühlmediums im Bereich der Laufbeschaufelung;

FIG 10

eine Darstellung noch einer weiteren Gestaltungsmöglichkeit des Kanalsystems zur Leitung des Kühlmediums im Bereich der Laufbeschaufelung;

FIG 11

eine Darstellung zur Gestaltung eines Abschirmblechs in einem Überlappungsbereich.

The figures in the drawing show in detail:

FIG. 1

a known cooling concept in a steam turbine rotor, which is limited to cooling in the inflow region of the working medium;

FIG 2

a schematic representation of a cooling concept in a steam turbine rotor according to a preferred embodiment;

FIG 3

a representation of the supply of the cooling medium and the line of the cooling medium in a rotor-integrated, near-surface channel system in the blading area in the preferred embodiment;

FIG 4

a detailed view along the section AA in the channel system of Figure 3;

FIG 5

a detailed view along the section BB in the channel system of Figure 3;

FIG 6

a detailed view along the section BB in a modified design of the channel system of Figure 3;

FIG 7

a schematic representation of a possibility of transmission of the cooling medium in the area of the blade attachment according to the preferred embodiment;

FIG 8

a representation of a further transmission possibility of the cooling medium in the area of the blade attachment according to the preferred embodiment;

FIG. 9

a representation of a further design option of the channel system for directing the cooling medium in the area of the blading;

FIG 10

a representation of yet another design option of the channel system for directing the cooling medium in the area of the blading;

FIG 11

a representation of the design of a shield in an overlap area.

In principle, known steam turbine rotors are used as full-piece rotors and completely manufactured without active cooling systems. However, in the prior art according to US Pat. No. 6,102,654, as shown in FIG. 1, a steam turbine 1 is described, which is a cooling system limited to cooling in the inflow area having. This has one rotatable on an axis 2 arranged rotor 3, on the tubular shaft a number of Rotor blades 4 is arranged. These are in a stationary Housing 5 arranged with a guide blading 6. The Rotor 3 is on the rotor blades 4 by the in the inflow area 7 inflowing working medium 8 driven. additionally to the working medium 8 flows through a separate entrance area 9 a cooling medium 10 to the working medium 8. there cools the cooling medium 10 exclusively by flow a first ring 11 of the stationary guide blading and a shielding plate 12. This reduces the temperature load of the rotor 3 and the first guide vane ring 11 are reduced. In addition, cooling fluid 10 from an input region 9 of the cooling fluid 10 via the first Guide vane ring 11 directed to an area 14, the directly between the housing 5 and the first rotor blade 15 lies. As a result, the entrance space 9 of the cooling fluid 10 sealed against the working medium 8, the cooling fluid 10 acts as a barrier fluid. The channel 13 itself is as Blocking line designed and does not act as a cooling line.

When the rotor 3 is cooled, cooling steam 10a is passed through a separate branch channel 16a a substantially central Cavity 16b, which runs parallel to the rotor axis, supplied. From there, such cooling steam 10a is also separated radial branch channels 16 led out again. The Cooling steam 10a again becomes the main flow in areas 16c supplied to cool the rotor in one place. The cooling medium 10a essentially flows around the rotor 3 in an inflow region 7 and in a central cavity 16b. This ensures effective cooling of the rotor itself not given, because the cooling medium is guided in the central Cavity 16b takes place away from the rotor surface and thus not in a place of heat input. The separate channels 16a, 16 are as branch channels for cooling a specific one Place the rotor trained and can also not be effective Cooling of the rotor 3 cause radially from one central cavity 16b to an area of the main flow 16c run. The cooling of a rotor shown here according to the prior art is still in need of improvement it does not provide near-surface cooling. By the central cavity also occurs comparatively high rotor stress, but also the Processing effort for the attachment of the branch channels increased is. Furthermore, this concept does not offer a sufficient one Shielding the rotor shaft from the main flow of the Steam.

2 shows a schematic representation of a steam turbine 20 according to a particularly preferred embodiment. This has a rotor 21 with a number of rotor blades 24 on which is rotatable in a housing 23 with a number of Guide blades 22 is mounted. Turbine 20 with rotor 21 and Housing 23 extend along an axial extent 25. The rotatable rotor blades 24 grip like Fingers in spaces between the stationary guide vanes 22nd

The rotor 21 shown here has an outer side 26a. The outside 26a borders on one for receiving a main flow 27 of a fluid working medium provided outside space 27a. The rotor has a number of locations on the outside 26a, in each of which one row of blades 24 is held. It extends according to the particularly preferred Embodiment a channel system 28 for guiding a Cooling medium from a first area 28a along the locations for the blades 24 up to a second region 28b continuously.

The channel system has along the axial extent 25 a number of openings 29 to the main flow 27. This serve in cooperation with the passage openings of the Channel system for the gradual pressure reduction of the cooling medium parallel to the main flow 27. From stage to stage of Blades 24 can preferably pass through the cooling medium Flow resistances are throttled. For this, for example in each case at a blade stage 24, the Passage of the cooling medium through a hole. When throttling the pressure is reduced without performing any technical work. The cooling medium has a similar pressure and lower Temperature a higher density than the flow medium in the main flow, which results in better heat transfer behavior results. By throttling and increasing the temperature This can advantageously increase the volume of the cooling medium be compensated for that gradually part of the Cooling medium delivered to the main flow through the openings 29 becomes. This also ensures a good adjustment of the cooling medium pressure reached the pressure of the main flow. This one The embodiment described thus represents an open cooling system represents.

In principle, one could in the preferred embodiment Steam turbine rotor also a variant not shown here of a cooling system as a closed cooling system be provided. There are some disadvantages, but if necessary, accepted if required can be. With a closed cooling system, a Delivery of the cooling medium to the main flow 27 not or only realized at the end of the refrigerated area. So it would the openings 29 of the open system of FIG 2 essentially omitted. Coolant would only come from a first one Area 28a passed to a second area 28b without thereby an immediate pressure adjustment to the main flow would be done. The gradual decrease in pressure could also by throttling. A levy of Cooling medium to the main flow does not take place in any case Blade level 24 instead. So with a closed cooling system for example, a delivery of the cooling medium to the Main flow 27 not at all, only in the end region 28b or only at a greatly reduced number of stages 24. The pressure in the duct system is therefore only indirectly to the Main flow adjusted. The disadvantage here is that for the cross section required by increasing the temperature and pressure reduction with a closed cooling system grow significantly in the course of the canal system. This leads to an undesirable reduction in the load-bearing cross-sections of blade feet and / or the rotor, since one configuration of the channel system 28 as a closed channel system from a first area 28a to a second area 28b would have to increase in cross section in order to increase the Volume flow. Although this runs the strength requirements in the rotor and blade attachment area contradicts, but could be compensated. Should the cooling medium after performing the cooling task not to the working medium can be delivered, for example, due to to different pressure and temperature parameters, so would the cooling medium in an area 28b separate from the working medium are guided out of the rotor 21. When cooling several Levels 24 with a closed system arise depending on covered expansion area, a high differential pressure between flowing medium in the main flow 27 and the cooling medium in the closed duct system when the openings 29 of FIG 2 are not present. Depending on the choice of the Coolant pressure due to a relatively poor cooling effect or at high coolant pressure due to a relatively higher differential pressure load of the components marked. At a low density of the cooling medium has a low heat capacity and thus causes a worse Heat transfer. Nevertheless, it is also one closed system around an active cooling system that the Steam turbine rotor 21 compared to passive cooling or compared to only limited cooling in the inflow area of a rotor can cool considerably better.

The open channel system 28 has a continuous one close to the surface, from which several branches turn towards the openings 29. Furthermore, it acts in the embodiment shown here is also a coherent one Channel system 28 in the sense that if possible separate additional channels that run out of the rotor surface could be avoided. This has the advantage that the cooling steam mass flow can decrease from stage to stage and that the same cooling steam works over several stages can. In comparison to known from the prior art of FIG 1 Individual channels 16 for a rotor or 13 for one Housings that are guided separately measure the required That is, pressure after the highest pressure of the main flow. In the separate channels according to the prior art a pressure for the subsequent stages would no longer be adjusted. This leads to an additional strain on the Turbine due to a higher differential pressure. Also would higher pressure in separate channels for several rows of blades to a significant increase in mechanical stress of the steam turbine rotor. Would also need for separate Channels an additional effort for deployment different pressure levels are made available, which is disadvantageous. In principle, however, as in general Part of the description explained, as part of a modification an implementation system designed flexibly and also be made up of subsystems.

In Figure 3 is a steam turbine rotor 30 according to the preferred Embodiment in the cooled blading area shown in more detail. A corresponding steam turbine 31 also has a housing, not shown, with a guide blading 32 on. The steam turbine rotor 30 sees a first one Site 30a and a second site 30b along the outside 33 before, along the axial extent 34 the second Point 30b is arranged behind the first point 30a. The Outside 33 is adjacent to an outer space 35 which for Recording a main flow 36 of a fluid working medium is provided. However, in this case the outside is 33 not formed by the actual surface of the rotor shaft, but through a shielding plate that rotates with the rotor 38, which is held by the blade feet 39a, 39b is. The blade feet 39a, 39b are still in blade grooves 40a, 40b anchored. A number of blades 41a will along the circumference of the rotor 30 side by side and each arranged in radial orientation 42 and thus forms a first, also known as a blade stage at location 30a. Correspondingly, a number of second Scoops 41b circumferentially at a second location 30b arranged in the groove 40b and forms a second Blade row.

A supplementary or alternative modification to that in FIG. 3 shielding plate 38 shown could also be worked on Shielding surface on the blade feet 39a, 39b. This would mean additional material and manufacturing costs may be required, however, a similar one Shielding effect can be achieved as with a shielding plate 38 and be beneficial as needed.

The channel system 43 of FIG 3 has at least one between a first area arranged in front of the first location 30a and one behind the first location 30a and in this embodiment also arranged behind the second location 30b second area continuously extending passage 44th on. The bushing 44 extends in this embodiment practically along the entire blading area of the rotor (length as required). Implementation 44 is on the one hand by the wall 37 of the rotor 30 and on the other formed by the shield plate 38. A variety of such Feedthroughs 44 are circumferential in the axial direction 34 arranged along the outside 33 of the rotor 30. The channel system 43 also has a number of circumferential Grooves 45 along that in this embodiment the axial extent 34 each at the level of a guide vane 32 are arranged. The guide vane 32 has one Cover plate 32a. The duct system 43 can by milling in the surface 37 of the rotor shaft be applied and by flat components of the Shielding plate 38 are covered. The channel system refers 43 also blade grooves (FIG 9, FIG 10) and / or bores 46a, 46b (FIG 5, FIG 6, FIG 9, FIG 10) in blade roots 39a, 39b into the flow.

The feed-through system 43 also has openings 47, 48 and 49 to adjust the pressure of the coolant flow to the Pressure of the working medium flow by dispensing a part of the Coolant flow to the main flow.

Shielding by a shielding plate 38 in the blading area can also shield the inflow area of the cooling medium by means of another shielding plate which is not shown here, and others Advantages with regard to the oxidation of the turbine rotor material brings with it.

As an alternative or in addition to a shielding plate 38, a Implementation system 43 or an implementation 44, 45 also in Form of holes or other suitable means within of the rotor 30 near the surface.

FIG. 4 shows the view of section A-A of FIG. 3. The circumferential groove 45 of FIG 3 is in dashed lines Line executed. Accordingly, the axial groove 44 is as Indentation in the surface 37 of the rotor shaft of the Steam turbine rotor indicated schematically.

5 shows a possibility of making a bore 46a in a blade root 39a. A lot along the rotor Blade feet 39a, 39a 'arranged circumferentially next to one another with bores 46a, 46a 'forms a row of blades on the Digit 30a.

An alternative embodiment of the bores 46a, 46a 'in FIG. 3 is shown in FIG. 6 as bore 46a ". A bore 46a" is attached in two adjacent blade roots 39a ".

• vor Eintritt in die der Teilturbine vorgeschalteten Überhitzerteile des Kessels,
• vor Eintritt in den Kessel überhaupt,
• nach dem Austritt aus einer vorgeschalteten Teilturbine,
• aus einer Anzapfung aus einer vorgeschalteten Teilturbine,
• durch separate Bereitstellung mittels einer geeigneten Pumpe, die das Kühlmedium an einer Stelle niedrigen Drucks aus der Vorwärmstelle entnimmt und auf den erforderlichen Druck bringt. Um einem Kühlungsausfall bei Ausfall der Pumpe entgegenzuwirken, ist ein zusätzlicher Aufwand, gegebenenfalls ein redundanter Aufbau erforderlich.

In contrast to gas turbines, with steam turbines the working medium flowing into a partial turbine with the highest temperature has the highest pressure at the same time. In order to implement, in particular, an open cooling system for a steam turbine, suitable measures for supplying the cooling medium must be taken. After the removal of such a medium from the water-steam cycle, the cooling medium can be supplied at a point of higher pressure and sufficiently low temperature. Suitable tapping points are in particular:

• before entering the superheater parts of the boiler upstream of the partial turbine,
• before entering the boiler at all,
• after leaving an upstream turbine section,
• from a tap from an upstream turbine section,
• through separate provision by means of a suitable pump, which takes the cooling medium from the preheating point at a low pressure and brings it to the required pressure. To counteract a cooling failure in the event of a pump failure, additional effort, possibly a redundant structure, is required.

7 shows a possibility 70 for the transmission of a cooling medium 71 from an area 72 in front of a first row of guide vanes 78 in a further area 73 of the blade attachment along the axial extent 74 behind the first Guide vane series 78. An inner housing is shown here 76 a, which in an outer casing 76 of a steam turbine 77 is appropriate. The cooling medium can be supplied via a feed 70 in a near-surface channel system 79 is introduced into the rotor 75 be and along the axial extent 74 in the area of Run blading 75a are performed. In parallel, it can Coolant flow through the sealing area (cooling, Reduction of enthalpy losses).

The flow 69 of the cooling medium 71 in the outer housing 76 is used Cooling the outer case. The inflow of the cooling medium will valves that meet safety requirements regulated.

In addition to the possibility of introducing 70 the cooling medium in FIG. 7, cooling medium could also be in the area of the inflow of the working medium in the rotor-integrated channel system 79 be initiated. FIG 8 shows another advantageous Possibility of introducing cooling medium 80 at a preferred embodiment, which in a turbine 1 1 according to the prior art is now close to the surface Provides cooling. The corresponding ones Parts of the turbine 1 according to the prior art and Turbine 81 according to the particularly preferred embodiment are provided with the same reference numerals. Below is the active cooling system for guiding the cooling medium 80 active cooling of the rotor 83 described. The cooling medium 80 is on the one hand via an entrance area 9, as already in 1 shows an inflow region of the working medium 8 fed. Furthermore, it is covered by a shield 12 passed through and in a room 82 behind the Shielding plate 12, the cooling medium 80 along the axial Expansion 85 within the rotor wall near the surface, d. H. in the area 84 of the attachment of the rotor blades 15 guided. In particular, the cooling medium 80 is along the axial Extension 85 at least between one before the first Blade ring 15 arranged first area 82 and a arranged behind the first rotor blade ring 15 second Area 88 managed throughout. In this embodiment the turbine 81, the first region 82 is used to Cooling medium 80 the near-surface axial bushing system to feed the rotor 83. Although not shown here, the cooling medium 80 can also practically along the entire run blading area of the rotor 83 (actual design (length) according to technical Requirements). In particular, individually or in Combination - all other described with reference to the other figures Measures to train the active cooling system can be provided in the turbine 81. In particular, too in this embodiment of FIG 8, the cooling system as an open Cooling system designed.

If the cooling medium escapes at the end of the duct system into the Main flow is not only the cooling medium of the main flow in pressure, but also in the temperature of the main flow largely adapted. This is due to the absorption of heat of the cooling medium in the cooled blading area. The cooling medium then takes part in further expansion in the mainstream Part. This is a particular advantage of an open one Cooling system, which thus enthalpy transport from the cooled Blading area in the non-cooled area.

The safety-related monitoring of the cooling medium has the embodiment shown here, especially the temperature of the cooling medium. It should be noted that a premature condensation / droplet formation in the flow and is excluded in the duct system even with partial loads. Of Furthermore, the essential components should overheat like rotor, blades or blade attachments for all relevant Load cases must be excluded. According to technical requirements there may be a mismatch between turbine valves and Coolant valves are provided.

The described channel system of the preferred embodiment can also be used advantageously for preheating purposes by suitable medium is fed in during the start-up process. This can also be done from other parts of the water-steam cycle be removed as the actual cooling medium. The fact that the preheating medium has an advantageous effect is throttled in the duct system and at least here does not contribute to the start-up of a shaft train. Analog can this method can also be used for rapid cooling. For future rotors or rotor materials, the ones described can Approaches an advantage in terms of Offer arrival times and cooling times.

9 shows a further design of a channel system for Conduction of the cooling medium in the area of a blade root 90, which is anchored in a groove 91 in a turbine rotor 92. The axial feedthrough 93 of the preferred embodiment is in the area of a guide vane 94 deeper inside a Rotors 92 embedded and thus has an example triangular shape in the area of the housing blade 94 on. Any other course is possible. Implementation 93 is open to the main flow via channels 99. In the area a blade groove 95 is also included in the implementation. In addition, the implementation is carried out by a blade root 90 by means of a channel 96 which is above the waist 97 of the blade root arranged closer to the blade 98 is. This has the advantage that the strength of the Bucket foot waist 97 is not affected.

FIG. 10 shows a further design similar to that in FIG 9 shown. In contrast to FIG 9 takes place a passage 106 also in the area of an airfoil 108. In the area of the airfoil 108 proceed from the implementation 106 channels 110, which cooling medium from a bushing 106 to the airfoil surface 108 to to provide film cooling.

Furthermore, cooling medium is also channeled in the area 109 a housing blade 104 to the main flow of the working medium issued. More details 100, 101, 102, 103, 107 correspond to those shown in FIG.

11 shows a favorable arrangement of a first shielding plate 120 and a second shield plate 121 in the area a joint 122 shown. The detailed version shown here can be advantageous with a shield 38 Through openings 123 and 124 in FIG 11 or 47, 48 and 49 be made in FIG 3. Such a shield is advantageously from a suitable, e.g. B. heat resistant material manufactured. In this version it consists of sections 120, 121, which preferred 122 at their joints a cover that is movable for different temperatures 125, 126.

In the embodiment shown in FIG 3, the shielding plate is located in the area of the guide vane cover plates and should be appropriate Sealing tips, d. H. have non-contact seals. For this purpose, sealing tips could be screwed all around, d. H. be made from the solid, or sealing tapes caulked become. What turns out to be advantageous can depending on the strength and manufacturing requirements of the material and the construction in detail.

If the cooling medium over the shaft seal of the guide vanes given to the main flow, the Loss of efficiency due to the flowing over these seals Leakage mass flow can be reduced. The leakage mass flow exists in this case not from the hot medium of the main flow, but from cooling medium with lower enthalpy. possibly however, this effect is due to a smaller number of sealing tips due to the space required for introduction of the cooling medium is consumed again.

In summary, a steam turbine rotor is a steam turbine and a method for actively cooling a steam turbine rotor and a suitable use of the cooling is proposed Service.

In previously known steam turbines 1, a rotor is either only passively or only in an inflow area of the working medium actively cooled to a limited extent. With an increasing Stress on the rotor due to increased steam parameters the working medium is sufficient cooling of the steam turbine rotor no longer guaranteed. The proposed one Steam turbine rotor 21, 30 extends along an axial Extension 25, 34 and has: a near-surface Channel system along the axial extent 25, 34, a Outside 26a, which borders on an outer space 27a, 35, the for receiving a main flow 27, 36 of a fluid working medium 8 is provided along a first point 30a the outside 26a, 33 at which a first blade 41a is held is a second location 30b along the outside 26a, 33, in which a second blade 41b is held, wherein along the axial extent 25, 34 the second point 30b is arranged behind the first location 30a. To guarantee sufficient cooling is at least one Implementation 44, 46a, 46b, 93, 96, 103, 106 provided the arranged, close to the surface, at least between one first region 28a, 72 arranged in front of the first point 30a and a second one located behind the second location 30b Area 28b, 73 extends continuously. It will be a procedure and proposed use in which a fluid cooling medium 10 is performed accordingly.

Claims (25)

Steam turbine rotor (21, 30, 75) which extends along an axial extent (25, 34), comprising: an outer side (26a) which borders on an outer space (27a, 35) which is provided for receiving a main flow (27, 36) of a fluid working medium (8), a first point (30a) along the outside (26a, 33), at which a first blade (41a) is held, marked by at least one integrated bushing (44, 46a, 46b, 93, 96, 103, 106), which is arranged at least between a first region (28a, 72) arranged in front of the first point (30a) and one behind the first point (30a) second region (28b, 73) extends continuously. Steam turbine rotor according to claim 1,
marked by
a second location (30b) along the outside (26a), at which a second blade (41b) is held, the second location (30b) being arranged behind the first location (30a) along the axial extent (25, 34) and the bushing (44, 46a, 46b, 93, 96, 103, 106) being at least between a first area (28a, 72) located in front of the first location (30a) and a second area (behind the second location (30b) ( 28b, 73) extends continuously. Steam turbine rotor according to claim 2,
characterized in that
A number of further points are arranged between the first point (30a) and the second point (30b), each of which has a blade (41a, 41b). Steam turbine rotor according to one of claims 1 to 3,
characterized in that
the at least one bushing (44, 46a, 46b, 93, 96, 103, 106) is part of a coherent bushing system (43) which extends along the axial extent (25, 34). Steam turbine rotor according to one of claims 1 to 4,
characterized in that
the at least one bushing (44, 46a, 46b, 93, 96, 103, 106) is part of a coherent bushing system (43) which has an external feed (70) which is provided for the inflow of cooling medium (10, 71) , Steam turbine rotor according to one of claims 1 to 5,
characterized in that
the at least one bushing (44, 46a, 46b, 93, 96, 103, 106) is part of a coherent bushing system (43) which has a channel (45) which at least partially runs around a circumferential extension of the rotor (21, 30, 75) having. Steam turbine rotor according to one of claims 1 to 6,
characterized in that
the first region (28a) has a first opening (49, 99, 109) to the main flow (27, 36). Steam turbine rotor according to one of claims 1 to 7,
characterized in that
the second region (28b) has a second opening (47, 99, 109) to the main flow (27, 36). Steam turbine rotor according to one of claims 1 to 8,
characterized in that
the outside (26a) of the rotor (21, 30, 75) is formed by a shielding plate (38) which can be rotated with the rotor (21, 30, 75). Steam turbine rotor according to one of claims 1 to 9,
characterized in that
a shielding plate (38) rotatable with the rotor (21, 30, 75) is held by a blade (41a, 41b), in particular a blade root (39a, 39b). Steam turbine rotor according to claim 9 or 10,
characterized in that
a shielding of the rotor shaft against the main flow of the steam is at least partially formed by a blade root (39a, 39b). Steam turbine rotor according to one of claims 1 to 11,
characterized in that
the bushing (46a, 46b, 96, 106) is guided through a blade (41a, 41b), in particular through a blade root (39a, 39b). Steam turbine rotor according to one of claims 1 to 12, characterized by
a groove (40a, 40b) on a blade root (39a, 39b), which is part of the passage (44). Steam turbine rotor according to one of claims 1 to 13, characterized by
a bore (46a, 46a ') through a single blade root (39a, 39a') and / or a bore (46a ") through two adjacent blade roots (39a"), which is part of the passage (44). Steam turbine rotor according to one of claims 1 to 14, characterized by
a channel (106, 110) in an airfoil (108) which is connected to the bushing (44). Steam turbine rotor according to one of claims 1 to 15,
characterized in that
a thermal insulation coating made of a material is provided on a blade surface, which has a lower thermal conductivity than the base material of the blade. Steam turbine (77, 20),
comprising a steam turbine rotor (21, 30, 75) according to one of claims 1 to 16. Method for active cooling of a steam turbine rotor (21, 30, 75),
which extends along an axial extent (25, 34) and an outer side (26a) which borders on an outer space (27a, 35) which is provided for receiving a main flow (27, 36) of a fluid working medium (8), a first point (30a) along the outside (26a, 33), at which a first blade (41a) is held, having,
characterized in that a fluid cooling medium (10, 71) within the steam turbine rotor (21, 30, 75) along the axial extent (25) at least between a first region (28a, 72) arranged in front of the first location (30a) and one behind the first location ( 30a) arranged second area (28b, 73) is guided continuously. A method for actively cooling a steam turbine rotor according to claim 18,
characterized in that
the steam turbine rotor (21, 30, 75) has a second point (30b) along the outside (26a, 33), at which a second blade (41b) is held, the second point (25, 34) along the axial extent (25, 34) 30b) is arranged behind the first point (30a) and the fluid cooling medium (10, 71) is at least between a first area (28a, 72) arranged in front of the first point (30a) and a second one arranged behind the second point (30b) Area (28b, 73) is guided continuously. A method for actively cooling a steam turbine rotor according to claim 19,
characterized in that
the cooling medium (10, 71) in a coherent bushing system (43) along the axial extent (25, 34) via the first location (30a) and the second location (30b) and a number of intermediate locations (24) at which one blade (41a, 41b) is held, is guided. Method for active cooling of a steam turbine rotor according to one of claims 18 to 20,
characterized in that
the cooling medium (10, 71) is fed to the steam turbine rotor (21, 30, 75) from outside (70). Method for active cooling of a steam turbine rotor according to one of claims 18 to 21,
characterized in that
the cooling medium is guided at a pressure which exceeds a pressure of the main flow (27, 36). Method for active cooling of a steam turbine rotor according to one of claims 18 to 22,
characterized in that
the cooling medium (10, 71) is guided at a pressure which is adapted (47, 48, 49, 99, 109), in particular throttled, as a function of a pressure of the main flow (27, 36). Method for active cooling of a steam turbine rotor according to one of claims 18 to 23,
characterized in that
the cooling medium (10, 71) is supplied at a temperature and / or an amount which is adjusted (47, 48, 49, 99, 109) as a function of a temperature of the main flow (27, 36). Use of active cooling of a steam turbine rotor (21, 30, 75) for starting and / or shutting down a steam turbine (77, 20), in particular for the rapid cooling of a steam turbine (77, 20).

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