DE102017215371A1 - Hohlleitschaufel - Google Patents

Abstract

The present invention relates to a hollow blade (100) for a turbine, in particular a steam turbine, and to a method for producing a hollow blade (100) for a turbine, in particular a steam turbine. The hollow blade (100) has an outer wall and an inner structure (110). The outer wall has a leading edge (101) and a trailing edge (102), wherein the leading edge (101) and the trailing edge (102) by means of a pressure side (103) and a suction side (104) are arranged, which are arranged spaced from each other, in that an outer surface of the outer wall can be formed as a flow profile, wherein the outer wall encloses an inner volume. Further, an inner structure (110) is formed in the inner volume and manufactured by additive manufacturing.

Description

Technical area

The present invention relates to a hollow blade for a turbine, a turbine and a method for producing a hollow blade for a turbine.

Background of the invention

In today's steam turbines, steam turbine end stage blades are often subject to high erosion stresses during operation, resulting from an impact of water droplets entrained in the vapor. The greatest erosion effect arises from the collection of water on the upstream vanes, which then comes in strands to the Leitschaufelkante and tears off in the form of drops. These are then carried along by the current and break down into smaller, but still erosion-effective drops. Due to the inertia of the water droplets in comparison to the steam flow, these reach only a small final speed up to the final stage blades and collide with a high differential speed.

In particular, a conventional hollow blade as in 7 represented a trained with uniform wall thickness and bent from a sheet and welded together outer wall 701 on. The outer wall 701 encloses an internal volume 702 , As in 8th shown is the hollow scoop 810 conventionally in the turbine 800 built in that the hollow scoop 810 on the outside diameter 811 with an outer channel 805 is connected and on the inner diameter 812 , ie near the hub, with an inner channel 806 connected is. Here are the outer channel 805 and the inner channel 806 like that in the turbine 800 integrated that the internal volume 702 with the turbine over the outer channel 805 and the inner channel 806 is in fluid communication.

The strain caused by slowly changing drops of water is so strong that the final stage blades have to be protected by technical measures. These include, depending on the moisture content of the flow a) hardening of the blade leading edges, b) extraction of the moisture collecting on the guide vane by hollow vanes and / or c) vaporization of the moisture present on the vanes by internal heating of the hollow vanes by means of steam.

The measures a) to c) are also arranged ascending in their effect. In particular, the steam heating means a great complexity, which is received only when the effect of a suction is no longer sufficient.

The extraction has only a limited effect under light load or with small mass flows (for example due to large amounts of heat and cogeneration). Here, the driving pressure difference across the Absaugequerschnitten decreases, so that the occurring moisture can not be completely removed. The erosion protection by wet suction is in need of improvement in terms of its use for high moisture content and low partial loads.

In a Leitschaufelheizung an internal pressure stress of the blade profile is generated by the heating steam. For receiving connections in the hollow profile between the suction and pressure side of the profile are made. Exceeding the allowable pressures and temperatures may result in deformation or failure of the blade. The blade is fully pressurized on the inside, which in addition to the mechanical stress mentioned can also lead to excessive consumption of heating steam. The erosion protection by Leitschaufelbeheizung is therefore in need of improvement in terms of mechanical strength and Heizdampfeinsatzes.
Usually, components are provided as an inner structure, which are located on the inside of the hollow profile and which are introduced after the production of the hollow profile from the outside, such as inserted pins or pipe sections. This limits the possible functionality of the hollow blade. At the moment, profile flow cross-sections for suction purposes are used. These are currently introduced by machining in the starting material before the production of the blade profile. Limitations are also introduced here by the method since only cross-sectional shapes produced by machining are shown. Furthermore, the bending deformation for production limits the position and shape of the cross sections.

Presentation of the invention

It is an object of the present invention to provide a hollow blade having a flexible, complex geometry inner structure which is easy to manufacture.

This object is achieved with a hollow blade for a turbine, in particular a steam turbine, and a method for producing a hollow blade for a turbine, in particular a steam turbine.

According to a first aspect of the present invention, a hollow blade for a turbine, in particular a steam turbine is disclosed. The Hollow blade has an outer wall, which has a leading edge and a trailing edge. The leading edge and the trailing edge are connected by means of a pressure side and a suction side, which are spaced apart such that an outer surface of the outer wall is formed as a flow profile, wherein the outer wall encloses an inner volume. Further, the hollow blade has an inner structure formed in the inner volume and made by additive manufacturing.

The hollow blade is in particular a hollow guide vane. A plurality of hollow vanes together with a plurality of blades form one stage of the turbine. The vane is so firmly connected to the housing of the turbine, that the guide vanes may direct the working fluid, in particular the steam, to the subsequent rotor blades of the turbine in an angle which is optimally adapted to the prevailing operating condition.

The hollow blade is hollow. In particular, the outer wall encloses the inner volume of the hollow blade. As a result, the hollow blade can be designed with a lower weight than a guide blade with a solid profile.

The outer wall has a leading edge and a trailing edge, which are connected to each other by means of the pressure side or the suction side such that an outer surface can be formed as an airfoil. The airfoil is arranged in the turbine such that the working fluid strikes the leading edge at an optimum angle of attack. The geometry of the outer surface of the outer wall on the suction side and the pressure side is adaptable to the flow of the working fluid, that during the operation of the turbine, a flow separation of the working fluid from the outer wall may be suppressed as much as possible.

The wall thickness of the outer wall is adapted to the load condition and the forces acting on the hollow blade, such that the outer wall can absorb the forces acting on the hollow blade forces. However, the wall thickness is not formed too strong at the same time, so that the hollow blade is disproportionately heavy.

The inner structure is produced by means of an additive manufacturing, so that the geometry of the inner structure can be adapted to individually present conditions. In particular, the inner volume of the hollow blade can be divided into different sub-volumes, i. Volume ranges, to be divided. Thus, individually separated volume regions can be formed, in particular at the locations of the hollow blade, where the hollow blade on the outer surface of the outer wall of the working fluid is subjected to particularly high loads.

By means of the additively produced internal structure, for example a hollow blade with suction, a hollow blade with heating and a combined hollow blade can be provided. This is possible in particular by the additively manufactured internal structure, which can have an almost arbitrary geometric shape.

As preferred additive methods, for example, selective laser melting (SLM), selective laser sintering (SLS), selective heat sintering (SHS), electron beam melting (EBM), cladding, metal powder coating (MPA), cold gas spraying and electron beam melting (Electron Beam Welding = EBW) are used.

In a hollow blade with suction, the hollow blade is additionally equipped with a plurality of suction holes, which are adapted in size, number, position and shape to the expected wetness and which extend over a previously defined region of the hollow blade.

Holes (zero-dimensional), slots (one-dimensional) or other geometric shapes (two-dimensionally extended openings, for example sickles) are particularly suitable as suction openings. In addition to the local effectiveness of the extraction, the influence on the strength of the airfoil must be taken into account when selecting the openings.

Since the seepage on the hollow blades is well known for the different load cases, sufficient Absagequerschnitte can be arranged so that the locally occurring moisture is safely dissipated. In particular, many suction holes can be created at the top of the blade cross-section, in order to be able to dissipate the moisture which occurs more intensively on the outside over the entire run length of the profile. In contrast, in a middle region of the blade cross-section, the suction openings would only be arranged in the vicinity of the profile tip and, depending on the expected wetness, against the profile end. When placing the openings certain areas can be recessed targeted (for example, welds from the production of the hollow blade or for attachment of the blade to the Leitkränzen). In an advantageous embodiment, the suction openings are executed after the expected wet accumulation in a plant project specific specified execution.

In order to reduce the seepage at the upper blade portion of the hollow blade and suction holes can be arranged on the inner diameter of the guide vane rings. This can be done in particular in the vicinity of the vane position.

It has proven to be advantageous to contour the suction openings in their longitudinal direction, for example in order to increase their flow resistance for steam. This can be achieved for example by a sharp-edged design at the trailing edge, or by deflections / cross-sectional changes. In particular, the rejection cross sections should be just dimensioned so that a safe removal of moisture is achieved. Excessively large cross-sectional areas lead to the extraction of otherwise usable steam from the flow and thus to power losses.

In order to ensure sufficient suction even for light loads (low pressure difference), extended cross-sections (distributed over the blade area) can be created compared to conventional designs. Alternatively, the inside of the hollow vanes may be set at a lower pressure level, for example by connecting to low pressure positions in the condenser (air cooler bundle) or by creating a separate pressure sink (separate radiator and separate water ring pump for evacuation).

With a hollow blade with heating advantages in the strength against internal pressure stress and / or the heating effect can be achieved by a suitable internal structure. With regard to the compressive stress connecting webs between the pressure and suction side can be sized in the required cross sections. With suitable design (flat webs instead of round pins), these can also contribute to the transverse force transmission (thrust) and thus to the strength of the blade as a whole.

Another advantage can be achieved by limiting the heating to specific areas of the sheet. Evaporation of water in the erosion-critical areas (near the hub) and a corresponding consumption of heating steam are thus avoided. Furthermore, a better design against internal pressure is made possible by such a spatial restriction. Thus, a heating can be applied locally in the position where there is a significant wetness.

The leadership of the heating steam on the blade inside can be performed, for example, in circular arc-shaped bounded, axially extending cavities. The arcuate boundary is an advantageous form for the pressurization. Ensure adequate drainage of the resulting condensate. For this purpose, corresponding channels can be created in the internal structure. In a preferred embodiment, the heating is designed to execution, area, leadership and pressure level specific to the particular application.

In a combined hollow blade, the hollow blade has an area which serves for the suction, and a further area which serves for the heating. In this case, an area is equipped with features for suction (preferably in the area of high wetness). Another area is equipped with features for heating (preferably in the area downstream of the extraction). Due to the here proposed creation of an internal structure of the hollow blade such a design is possible for the first time. Furthermore, the internal structure can create connections between the two areas, for example, to dissipate the condensate produced during heating. Such a connection is to be dimensioned so that the condensate removal is guaranteed, but no impermissible pressure increase arises on the suction side.

In order to increase the mechanical strength of the hollow blade or to perform lower wall thickness, flat webs between the walls for local transmission of normal and shear forces can be provided. This applies regardless of the version for extraction or heating purposes. Furthermore, the wall thickness above the blade height (in the radial direction of the blade) and blade length (in the flow direction along the blade) can be modified, for example by providing a greater wall thickness at attachment areas (weld areas) or at high-stress areas (for example high bending stress).

For pressure- or media-transmitting connections to the internal structure, the hollow blade may have certain connection elements. For example, the entire hollow cross-section and a portion of the same can be available for the passage. Furthermore, tubular connections can be provided for the connection to the inner structure. Thus, for example, a suction can be attached to the cross section at the outer diameter, and in parallel a tubular connection for heating or a condensate feedthrough.

According to another aspect of the present invention, a turbine, in particular a steam turbine, is disclosed. The turbine has a hollow blade as described above, which is arranged in an inner channel or flow channel of the turbine.

The inner channel of the turbine is the flow channel through which flows the working fluid with which the turbine is operated. It is preferably a steam turbine operated with steam as the working fluid.

The turbine can be both a radial turbine and an axial turbine.

The hollow blade is preferably arranged as a hollow guide vane in a vane ring such that the radial direction of the turbine is parallel to the radial direction of the hollow blade.

According to a further aspect of the present invention, a method for producing a hollow blade for a turbine, in particular a steam turbine is claimed. The method comprises providing an outer wall having a leading edge and a trailing edge, the leading edge and the trailing edge joined by a pressure side and a suction side spaced apart such that an outer surface of the outer wall can be formed as an airfoil which includes an inner volume. Further, the method comprises additive manufacturing of an inner structure formed in the inner volume.

An embodiment provides that the hollow blade (or a substantial portion thereof) is manufactured by a three-dimensional method. This is understood to mean a method by means of which a three-dimensional blade having a complex internal structure as described above can be produced. An example is additive manufacturing. In additive manufacturing, a component is created by a continuous or step-by-step, geometry-creating application of material.

The additive manufacturing can be carried out, for example, by means of a metal powder application method, a 3D screen printing of metals or selective laser sintering.

In an exemplary embodiment of the present invention, the inner structure has a first connection element, which is designed such that the inner volume is divided into a first volume area and a second volume area.

The first volume region and the second volume region are separated from one another by means of the first connecting element such that the first connecting element is a wall between the first volume region and the second volume region. On the one hand, the first connecting element may be formed as a continuous wall, in which case the first volume area and the second volume area are separated from one another such that there is no fluid connection between the first volume area and the second volume area. On the other hand, the first connecting element may be connected by connecting bores. These connection bores can serve, for example, for condensate drainage, for dewatering or for pressure equalization between the first volume region and the second volume region.

Thus, a volume region may be a volume spatially separated from the entire interior volume of the hollow blade by at least one connecting element.

The first volume range can be arbitrarily large and have an arbitrary shape. The second volume region then has a shape or a size which corresponds to the total inner volume of the hollow blade minus the first volume region.

The radial direction corresponds to that direction of the hollow blade which is substantially parallel to the radial direction of the turbine, i. when the hollow blade is disposed in the turbine, the radial direction of the hollow blade is substantially parallel to the radial direction of the turbine.

The first volume region and / or the second volume region may extend in the radial direction of the hollow blade over the entire radial extent of the hollow blade. However, either the first volume region or the second volume region may extend only over a portion of the radial extent of the hollow blade. The decision as to whether one or both volume regions extend over a partial section or the entire radial extent of the hollow blade is dependent in particular on the present boundary conditions and the present load case.

The first volume region advantageously extends in the inner volume of the hollow blade over a region which is subject to particularly high loads on the outer surface of the outer wall, for example due to the impact of working fluid of the turbine.

In an exemplary embodiment of the present invention, the first connection element is configured such that a first contact region of the first connection element is connected to the suction side and a second contact region of the first connection element is connected to the pressure side.

A contact region is an end region of the connecting element, which is firmly connected to the outer wall.

The first contact region is connected to the suction side or the second contact region is connected to the pressure side means that the first connection element extends from the pressure side to the suction side, wherein the first volume region extends upstream of the first connection element and the second volume region extends extending downstream of the first connecting element. Thus, a subdivision of the inner volume of the hollow blade in a direction of flow, which extends from the leading edge to the trailing edge, "front" first volume region and a "rear" second volume region.

Advantageously, the first connecting element can additionally transmit pressure forces acting on the pressure side or tensile forces acting on the suction side to the corresponding other side or transmit thrust forces from the suction side to the pressure side and vice versa, so that the suction side and the pressure side each have a smaller one Wall thickness can be formed.

On the one hand, the connection between the first connecting element and the suction side or pressure side is already advantageously carried out during the manufacture of the hollow blade by common additive manufacturing. On the other hand, the connection between the first connecting element and the outer wall can be carried out by means of additive manufacturing of the first connecting element in a first step and a subsequent joining to the outer wall in a second step.

In an exemplary embodiment of the present invention, the first connection element is configured such that a first contact region of the first connection element and a second contact region of the first connection element are connected to the pressure side such that the first volume region is enclosed between the pressure side and the first connection element to form an inner channel. Alternatively, the first connection member is formed such that a first contact portion of the first connection member and a second contact portion of the first connection member are connected to the suction side such that the first volume portion is sandwiched between the suction side and the first connection member to form an inner channel.

Thus, advantageously, an inner channel can be formed selectively on the suction side and / or pressure side. In particular, viewed in the flow direction, an inner channel can be arranged on the pressure side at a different location than a further inner channel on the suction side. Also, fluids having different properties may be passed through the various separate inner channels, depending on the characteristic required in the inner channel, such as pressure, temperature, saturation.

The inner channel may extend over the entire radial extent of the hollow blade or only over a portion of the radial extent of the hollow blade. For example, when the inner channel extends over the entire radial extent of the hollow blade, fluid may be directed from the radially outer turbine housing to the radially inner turbine hub and vice versa. This can be advantageous, for example, in the heating, as a result of which a heating fluid can be conducted over the entire radial length of the hollow blade. If the inner channel extends over a radial section of the hollow blade, for example, a working fluid can be sucked from the flow channel of the turbine by means of a suction provided on the hollow blade through the first volume region.

In an exemplary embodiment of the present invention, the first connection member has a cross section with a normal parallel to a radial direction of the outer wall. The first connecting element has in the cross section at least one shape from the following group: arc, semicircle, rectangle, drop, half drop and circle.

The radial direction of the outer wall is substantially parallel to the radial direction of the turbine. Thus, the normal is parallel to a radial direction of the outer wall, that the cross section is formed at the radial point at which the cross section is formed at right angles to the outer wall. Thus, the normal of the cross section is parallel to the tangent to the outer wall at the radial point of the cross section.

The chosen shape of the cross section depends in particular on the choice of fluid used to flow through the inner channel and the desired amount of fluid used. Also, the choice of the shape of the cross section depending on the use of the inner channel depend. The outer wall has a partial section, which forms a section of the boundary wall of the inner channel. If working fluid at any point of the inner channel in contact with the outer wall in a uniform amount in contact, offers an arcuate or semicircular cross-section. On the other hand, if, for example, at an upstream location of the inner channel more fluid with the outer wall in contact occur as at a downstream location, offers a semi-drip-shaped cross section, the greater extent, seen in cross section, upstream of the narrow converging section, seen in cross section, is arranged.

In an exemplary embodiment of the present invention, the first connection element is configured such that the first connection element is connected to the pressure side and / or the suction side along the entire extent of the outer wall in a radial direction of the outer wall such that the first volume region between the pressure side or the Suction side and the first connecting element is included to form an inner channel.

The inner channel extends over the entire radial extent of the hollow blade. Advantageously, thus, a fluid connection can be made through the inner channel between the radially inner hub and the radially outer turbine housing.

The inner channel is arranged at a point in the flow direction of the pressure side or suction side, which is located between the leading edge and the half, in particular a third, between leading edge and trailing edge. In this region of the hollow blade, the introduction of a separate inner channel with respect to a possible extraction can be particularly effective.

In an exemplary embodiment of the present invention, the first connection member is formed such that the first connection member extends from a radially outer end of the outer wall toward a radially inner end of the outer wall. Further, the first connection member is formed such that the first connection member is connected to the pressure side and / or the suction side along a partial extension of the outer wall in a radial direction of the outer wall such that the first volume region between the pressure side or the suction side and the first connection member is enclosed to form an inner channel.

The inner channel can advantageously extend over a radial portion of the hollow blade. In particular, the inner channel has an opening either at the radially outer end of the hollow blade or at the radially inner end of the hollow blade, i. the first connecting element is at the radially inner or outer end spaced from the outer wall of the suction side or pressure side, that at this point a fluid connection to a corresponding component of the turbine can be produced by means of the opening. At the radially opposite end of the inner channel, however, the first connecting element is firmly connected to the outer wall of the pressure side or suction side such that the inner channel terminates as a blind hole within the hollow blade.

In an exemplary embodiment of the present invention, the first connection element comprises at least one element from the following group: a cross connection and a support pin.

If, on the one hand, the first connecting element is designed as a cross-connection or, for example, as a web, the first connecting element can also absorb any transverse forces which may occur between the suction side and the pressure side.

If, on the other hand, the first connecting element is designed as a supporting pin, the first connecting element can transmit compressive forces and tensile forces in its longitudinal direction particularly well. Thus, the first connecting element may transmit any pressure forces and / or tensile forces between the pressure side and the suction side.

In an exemplary embodiment of the present invention, the outer wall is manufactured by additive manufacturing.

The outer wall is advantageously made additive together with the inner structure in a manufacturing process. Thus, the outer wall and the inner structure is a one-piece, i. one-piece component, which has no joining technically generated vulnerabilities. Advantageously, a separation of inner structure and outer wall can be prevented.

According to an alternative embodiment, the outer wall and the inner structure can each be produced in an individual additive manufacturing process and then joined together. Advantageously, the inner structure and the outer wall can be made of different materials, which are not accessible to a common additive manufacturing.

In an exemplary embodiment of the present invention, the outer wall has at least one through-hole. Furthermore, the at least one through-bore is arranged at a location of the outer wall on which the first volume region is present, such that the at least one through-bore establishes a fluid connection between the first volume region and an environment of the outer wall.

A fluid connection means that a fluid, which is located in the first volume region through the through hole in the Environment, in particular in the flow channel of the turbine, can flow. Conversely, working fluid from the environment, in particular the flow channel of the turbine, get into the first volume region of the hollow blade. The size and shape of the through hole is dependent on the fluid or working fluid used.

Moreover, to ensure fluid exchange across the at least one through-bore, a pressure differential between the first volume region and the environment is necessary. Advantageously, working fluid from the environment, in particular the flow channel of the turbine, is to be sucked into the first volume region. For this purpose, it is advantageous that in the first volume region, a lower pressure level than in the environment.

In an exemplary embodiment of the present invention, a cross-section of the at least one through-hole has a shape of the following group: circle, ellipse, drop, rectangle, polygon, slot and slot of varying width in the spanwise direction.

Advantageously, the selected cross-sectional shape of the through-hole depends on the properties of the working fluid used, in particular on the saturation, the density or the pressure. But also in the environment, in particular in the operation of the turbine, present parameters, which are well known, such as flow velocity or composition of the working fluid, affect the cross-sectional shape.

Advantageously, the at least one through-hole will have a larger width in the direction of extent at its upstream end than a variable-width slot at its upstream end than at its downstream end. In this case, a large part of the moisture can be sucked off right at the beginning of the impact and the remaining part is sucked in successively later. This is sufficient because a large part of the moisture is already sucked out on impact and thus only a small amount of moisture remains for later aspiration.

Further, the slot may be formed as a straight slot or a curved slot. A straight slot may extend exclusively straight along its extent. Whereas a curved slot, for example in its cross-sectional shape may have the shape of a semicircle, a wave or an S-shape.

In an exemplary embodiment of the present invention, the inner structure further comprises at least one second connection element, which is formed such that the inner volume has a third volume area.

The second connecting element can advantageously be produced by the same additive method as the first connecting element, wherein advantageously the outer wall, the first connecting element and the second connecting element are produced in a common manufacturing process by means of the same additive manufacturing method.

Furthermore, it is advantageous if the first connecting element and the second connecting element are designed differently, in particular if the first connecting element and the second connecting element are each adapted to individual conditions at the respective point of the hollow blade.

In an exemplary embodiment of the present invention, the third volume region is spaced from the first volume region.

Advantageously, the second volume region is arranged spatially between the first volume region and the third volume region such that the second volume region extends between the first volume region and the third volume region. Then, the first connecting element is in contact with its one side with the first volume region and with its other side with the second volume region. At the same time, the second connecting element with its one side is also in contact with the second volume area and with its other side with the third volume area.

Illustratively, the first volume region, for example, extends adjacent to the pressure side downstream of the leading edge over the radially outer third in the radial direction of the hollow blade. At the same time, for example, the third volume region extends adjacent to the pressure side upstream of the trailing edge via the radially outer half in the radial direction of the hollow blade. This arrangement is advantageous since larger amounts of condensed water droplets occur at these two points of the hollow blade than at the remaining hollow blade.

In an exemplary embodiment of the present invention, the outer wall has different wall thicknesses.

The wall thickness may in particular vary between regions of the pressure side or suction side, which may be the first volume region, the second volume region or the third Limit volume range. Thus, the conditions or fluid properties present in the respective volume range can be taken into account in the wall thickness of the outer wall.

For example, in a region of the outer wall at which the pressure difference between the pressure present in the volume range and the pressure of the environment is large, the wall thickness may be stronger than on the remaining hollow blade.

In an exemplary embodiment of the present invention, the first connection element has a first contact region, which is connected to the pressure side or the suction side such that the first connection element is formed as a rib.

If the first connection element is designed as a rib, i. as narrow on a smooth construction part fitted bar, the first connecting element can be connected to either the pressure side or suction side and serve to stiffen the pressure side or suction side. Also, in this case, the first connection element only has a first contact region, with which the first connection element is connected to the pressure side or the suction side. In addition, a rib can serve to improve the heat transfer. This has proved to be particularly useful in the heating of the inside.

In an exemplary embodiment of the present invention, providing an outer wall comprises additive manufacturing of the outer wall.

The outer wall can be made on the one hand by means of an additive method separate from the inner structure. On the other hand, the inner structure and the outer wall can be manufactured in a common additive manufacturing process.

It should be noted that the embodiments described herein represent only a limited selection of possible embodiments of the invention. Thus, it is possible to suitably combine the features of individual embodiments with one another, so that for the person skilled in the art with the variants of embodiment that are explicit here, a multiplicity of different embodiments are to be regarded as obviously disclosed.

list of figures

• 1 zeigt einen Querschnitt einer Hohlschaufel gemäß einer beispielhaften Ausführungsform der vorliegenden Erfindung.
• 2 zeigt eine Seitenansicht der Druckseite einer Hohlschaufel gemäß einer beispielhaften Ausführungsform der vorliegenden Erfindung.
• 3 zeigt einen Querschnitt einer Hohlschaufel gemäß einer beispielhaften Ausführungsform der vorliegenden Erfindung.
• 4 zeigt einen Querschnitt einer Hohlschaufel gemäß einer beispielhaften Ausführungsform der vorliegenden Erfindung.
• 5 zeigt einen Querschnitt einer Hohlschaufel gemäß einer beispielhaften Ausführungsform der vorliegenden Erfindung.
• 6 zeigt eine Seitenansicht der Saugseite einer Hohlschaufel gemäß einer beispielhaften Ausführungsform der vorliegenden Erfindung.
• 7 zeigt einen Querschnitt einer Hohlschaufel gemäß des Standes der Technik.
• 8 zeigt eine Seitenansicht einer Hohlschaufel in einem Strömungskanal gemäß des Standes der Technik.

In the following, for further explanation and for a better understanding of the present invention, embodiments will be described in detail with reference to the accompanying figures.

• 1 shows a cross section of a hollow blade according to an exemplary embodiment of the present invention.
• 2 shows a side view of the pressure side of a hollow blade according to an exemplary embodiment of the present invention.
• 3 shows a cross section of a hollow blade according to an exemplary embodiment of the present invention.
• 4 shows a cross section of a hollow blade according to an exemplary embodiment of the present invention.
• 5 shows a cross section of a hollow blade according to an exemplary embodiment of the present invention.
• 6 shows a side view of the suction side of a hollow blade according to an exemplary embodiment of the present invention.
• 7 shows a cross section of a hollow blade according to the prior art.
• 8th shows a side view of a hollow blade in a flow channel according to the prior art.

Detailed description of exemplary embodiments

The same or similar components are provided in the figures with the same reference numerals. The illustration in the figures is schematic and not to scale.

1 shows a cross section of a hollow blade 100 according to an exemplary embodiment of the present invention.

The radial direction of the hollow blade 100 is substantially parallel to the radial direction of the turbine, in which the hollow blade 100 is used. Furthermore, the hollow blade 100 arranged such that the flow direction 181 from the leading edge 101 to the trailing edge 102 runs.

The cross section has a normal which is parallel to the radial direction of the hollow blade 100 runs.

The hollow scoop 100 for a turbine, in particular a steam turbine, has an outer wall, which from the leading edge 101 and the trailing edge 102 which consists of a pressure side 103 and a suction side 104 are connected and which are spaced apart from each other are arranged, that an outer surface of the outer wall is formed as a flow profile.

The outer wall encloses an inner volume. In the inner volume is an internal structure 110 arranged, which is a first connecting element 111 , a second connecting element 112 and a third connecting element 113 having. The first connection element 111 is in the flow direction 181 upstream of the second connecting element 112 arranged. The third connection element 113 is downstream of the second connecting element 112 arranged. Consequently, illustratively speaking, the second connecting element 112 in the flow direction 181 between the first connecting element 111 and the third connection element 113 arranged.

The first connection element 111 , the leading edge 101 , one at the leading edge 101 downstream area of the suction side 104 and one to the leading edge 101 downstream adjacent area of the pressure side 103 close a first volume area 121 one. In the flow direction 181 between the first connecting element 111 and the second connection element 112 is the second volume range 122 locked in. Again in the flow direction 181 between the second connecting element 112 and the third connection element 113 is the third volume range 123 locked in. Further, between the third connecting element 113 , the trailing edge 102 , one in the flow direction 181 upstream of the trailing edge 102 located section of the suction side 104 and one upstream of the trailing edge 102 located section of the pressure side 103 a fourth volume range 124 locked in.

The first connection element 111 has a first contact area 151 and a second contact area 152 on. The first contact area 151 is with the suction side 104 and the second contact area 152 is with the print side 103 connected. The first contact area 151 is in the flow direction 181 seen closer to the leading edge 101 arranged as the second contact area 152 , The outer wall on the pressure side 103 has five first through holes 191 which provides fluid contact between the first volume region 121 and the environment 170 enable. The pressure level in the first volume range 121 is lower than the pressure level of the environment 170 , allowing a fluid flow from the environment 170 in the first volume range 121 is possible.

The outer wall on the suction side 104 has four second through holes 192 on which a fluid communication between the second volume range 122 and the environment 170 enable. Between the first volume area 121 and the second volume area 122 there is no fluid exchange.

Two of the four second through holes 192 are in the flow direction 181 downstream of three of the first five through holes 191 arranged, whereby the situation in flow direction 181 from two of the first through holes 191 and two of the second through holes 192 overlap.

The second connection element 112 and the third connecting element 113 are designed as a cross-connection, which in each case also lateral forces between the pressure side 103 and suction side 104 which may also transmit fluid communication between the second volume region 122 , the third volume range 123 and the fourth volume range 124 is possible.

2 shows a side view of the printed page 103 a hollow scoop 200 according to an exemplary embodiment of the present invention.

The hollow scoop 200 has a first connection element 211 and a second connecting element 212 on.

The first connection element 211 is with the print side 103 the hollow blade 200 connected and extends in the side view in the form of a hyperbola from the radially outer end 241 the hollow blade 200 to the trailing edge 102 , Furthermore, the first connection element extends 211 in the radial direction 280 along the radially outer third of the pressure side 103 and in the flow direction 181 along one third of the suction side 103 upstream of the trailing edge 102 , The means of the first connecting element 211 delimited first inner channel 225 thus extends as a blind ending blind hole at least along the pressure side 103 and the trailing edge 102 ,

The second connection element 212 is with the print side 103 the hollow blade 200 connected and extends in the side view in the form of a hyperbola from the radially outer end 241 to the leading edge 101 , Furthermore, the second connecting element extends 212 in the radial direction 280 along more than the radially outer half of the pressure side 103 and in the flow direction 181 along one third of the suction side 103 downstream of the leading edge 101 , The means of the second connecting element 212 delimited second inner channel 226 thus extends as a blind ending blind hole at least along the pressure side 103 and the leading edge 101 ,

Consequently, at the pressure side 103 the hollow blade 200 a Volumenberiech and a first internal channel 225 and a second inner channel 226 separated from each other.

3 shows a cross section of a hollow blade 300 according to an exemplary embodiment of the present invention.

The cross section has a normal which is substantially parallel to the radial direction of the hollow blade 300 runs.

The hollow scoop 300 has an outer wall, which has a leading edge 101 , a trailing edge 102 , a printed page 103 and a suction side 104 comprising, which together the flow profile of the hollow blade 300 form. The outer wall of the hollow scoop 300 includes an inner volume in which a first connecting element 311 , a second connecting element 312 and a third connecting element 313 are formed.

The first connection element 311 extends in cross-section semicircular from the first contact area 351 to the second contact area 352 , Both the first contact area 351 as well as the second contact area 352 are in the flow direction 181 spaced from each other with the pressure side 103 connected.

In the flow direction 181 downstream of the first connector 311 is the second connection element 312 arranged. The second connection element 312 is also semicircular in shape and has a first contact area 353 and a second contact area 354 on, which also both with the pressure side 103 are connected. The first contact area 353 of the second connecting element 312 is in the flow direction 181 downstream directly adjacent to the second contact area 352 of the first connecting element 311 with the pressure side 103 connected. The second contact area 354 of the second connecting element 312 is downstream in the flow direction 181 from the first contact area 353 of the second connecting element 312 spaced with the pressure side 103 connected.

The third connection element 313 is with the first contact area 355 of the third connecting element 313 with the pressure side 103 and with the second contact area 356 of the third connecting element 313 with the suction side 104 connected.

The inner volume of the hollow scoop 300 is by means of the first connecting element 311 , the second connecting element 312 and the third connecting element 313 in the first volume range 321 , the second volume range 322 , the third volume range 323 and the fourth volume range 324 divided. The third volume area 323 is through the first connecting element 311 , the leading edge 101 , one at the leading edge 101 adjacent section of the suction side 104 and a portion of the pressure side adjacent the leading edge 103 limited. The first volume area 321 is from the first connection element 321 and the print side 103 and the fourth volume range 324 from the second connecting element 312 and the print side 103 limited. Furthermore, the inner volume has the second volume area 322 on. Fluid communication between any contiguous volume areas is thereby prevented.

4 shows a cross section of the hollow blade 400 according to an exemplary embodiment of the present invention.

The hollow scoop 400 has the first connection element 411 , the second connecting element 412 and the third connecting element 413 on. In the flow direction 181 from the leading edge 101 to the trailing edge 102 First of all, this is the first connecting element 411 and then the second connecting element 412 arranged, wherein the second connecting element between the first connecting element 411 and the third connection element 413 is arranged. The first connection element 411 , the second connecting element 412 and the third connecting element 413 are each with the print side 103 on the one hand and the suction side 104 on the other hand. By the first connecting element, 411, the second connecting element 412 and the third connecting element 413 is the inner volume of the hollow blade 400 in the first volume range 421 , the second volume range 422 , the third volume range 423 and the fourth volume range 424 divided. In the flow direction 181 seen at first the first volume range 421 adjacent to the leading edge 101 , then the second volume range 422 , then the third volume range 423 and adjacent to the trailing edge 102 arranged the fourth volume range.

The outer wall has at the leading edge and at the leading edge 101 adjacent section of the suction side 104 as well as at the leading edge 101 adjacent section of the print page 103 six through holes 492 on which the first volume range 421 with the environment 170 connects such that a fluid exchange between the first volume range 421 and the environment 170 is possible. In this case, the first volume area 421 a lower pressure level than the environment 170 ,

5 shows a cross section of a hollow blade 500 according to an exemplary embodiment of the present invention.

The hollow scoop 500 has an internal structure 510 on which a single first connection element 511 having. This is with the first contact area 521 and the second contact area 552 with the suction side 104 connected and extends between the first contact area 551 and the second contact area 552 in the shape of a semicircle.

The first connection element 521 divides the inner volume into a first volume range 521 , which is arranged on the suction side and a second volume area 522 , which occupies the remaining inner volume and thus is significantly larger than the first volume range 521 ,

6 shows a side view of the suction side 104 a hollow scoop 600 according to an exemplary embodiment of the present invention.

The first connection element 611 is on the suction side 104 in the flow direction 181 closer to the leading edge 101 as at the trailing edge 102 arranged.

The first connection element 611 extends over the entire extent in the radial direction 280 the hollow blade 600 , Consequently, the radially inner end 642 of the inner channel 625 with the hub (not in 6 shown) and the radially outer end 641 of the inner channel 625 with the housing (not in 6 shown) in fluid communication.

In addition, it should be noted that "encompassing" does not exclude other elements or steps, and "a" or "an" does not exclude a multitude. It should also be appreciated that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims are not to be considered as limiting.

Claims (18)

Hollow blade (100) for a turbine, in particular a steam turbine, comprising an outer wall, which has a leading edge (101) and a trailing edge (102), wherein the leading edge (101) and the trailing edge (102) by means of a pressure side (103) and a suction side (104) are connected, which are arranged spaced from each other in that an outer surface of the outer wall can be formed as a flow profile, the outer wall enclosing an inner volume, and an inner structure (110) formed in the inner volume and fabricated by additive manufacturing. Hollow blade (100, 500) according to Claim 1 wherein the inner structure (510) comprises a first connecting element (111, 511) which is formed such that the inner volume is divided into a first volume region (121, 521) and a second volume region (122, 522). Hollow blade (100) according to Claim 2 wherein the first connection element (111) is formed such that a first contact region (151) of the first connection element (111) is connected to the suction side (104) and a second contact region (152) of the first connection element (111) is connected to the pressure side ( 103) is connected. Hollow blade (300, 500) according to Claim 2 wherein the first connection element (311) is formed such that a first contact region (351) of the first connection element (311) and a second contact region (352) of the first connection element (311) are connected to the pressure side (103) such that the first volume region (321) is enclosed between the pressure side (103) and the first connection element (311) to form an inner channel, or wherein the first connection element (511) is formed such that a first contact region (551) of the first connection element (551) 511) and a second contact portion (552) of the first connection member (511) are connected to the suction side (104) such that the first volume portion (521) is sandwiched between the suction side (104) and the first connection member (511) Inner channel to form. Hollow blade (300, 500) according to Claim 4 wherein the first connecting member (311, 511) has a cross section with a normal parallel to a radial direction (280) of the outer wall, wherein the first connecting member (311, 511) in the cross section has at least one of the following group: arc, semicircle , Rectangle, half drops and circle. Hollow blade (600) according to any one of Claims 3 to 5 wherein the first connecting member (611) is formed such that the first connecting member (611) is connected to the pressure side (103) and / or the suction side (104) along the entire extent of the outer wall in a radial direction (280) of the outer wall in that the first volume area between the pressure side (103) or the suction side (104) and the first Connecting element (611) is included to form an inner channel (625). Hollow bucket (200) according to any one of Claims 3 to 5 wherein the first connecting element (211) is formed such that the first connecting element (211) extends from a radially outer end (241) of the outer wall towards a radially inner end (242) of the outer wall, and wherein the first connecting element (211) 211) is formed such that the first connecting element (211) is connected to the pressure side (103) and / or the suction side (104) along a partial extent of the outer wall in a radial direction (280) of the outer wall, such that the first volume area between the pressure side (103) or the suction side (104) and the first connecting element (211) is enclosed to form an inner channel (225). Hollow blade (100) according to any one of Claims 2 to 7 wherein the first connection element (111) comprises at least one element from the following group: a cross connection and a support pin. Hollow blade (100) according to any one of Claims 1 to 8th , wherein the outer wall is made by additive manufacturing. Hollow blade (100) according to any one of Claims 1 to 9 wherein the outer wall has at least one throughbore (190), the at least one throughbore (190) being disposed at a location of the outer wall where the first volume region (121) is present, such that the at least one throughbore (190) fluidly interconnects the first volume region (121) and an environment (170) of the outer wall produces. Hollow blade (100) according to Claim 10 wherein a cross-section of the at least one through-hole (190) has a shape of the following group: circle, ellipse, rectangle, polygon, slot and slot of varying width in the spanwise direction. Hollow blade (100) according to any one of Claims 2 to 11 wherein the inner structure (110) further comprises at least one second connection element (112), which is formed such that the inner volume has a third volume region (123). Hollow blade (100) according to Claim 12 wherein the third volume region (123) is spaced from the first volume region (121). Hollow blade according to any one of Claims 1 to 13 , wherein the outer wall has different wall thicknesses. Hollow blade (100) according to Claim 1 wherein the first connection element has a first contact region which is connected to the pressure side or the suction side in such a way that the first connection element is designed as a rib. Turbine, in particular steam turbine, comprising a hollow blade (100) according to any one of Claims 1 to 15 wherein the hollow blade (100) is arranged in an inner channel of the turbine. A method for producing a hollow blade (100) for a turbine, in particular a steam turbine, comprising Providing an outer wall having a leading edge (101) and a trailing edge (102), the leading edge (101) and the trailing edge (102) being connected by a pressure side (103) and a suction side (104) spaced from one another in that an outer surface of the outer wall can be formed as an airfoil enclosing an inner volume, additive manufacturing an interior structure (110) formed in the interior volume. Method for producing a hollow blade (100) for a turbine, in particular a steam turbine, according to Claim 17 wherein providing an outer wall comprises additive manufacturing of the outer wall.

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