阅读说明：本技术 涡轮机内壳体 (Inner casing of a turbomachine ) 是由 D·纳斯 S·内加蒂-拉德 K·施克曼 于 2018-12-21 设计创作，主要内容包括：本发明涉及一种用于径向涡轮机(RTM)的涡轮机内壳体(TMI),其中涡轮机内壳体(TMI)具有沿着纵轴线(X)的接合部(TF)、特别是沿着转子纵轴线(RX)的接合部(TF),使得涡轮机内壳体(TMI)能够分成下部件(LPC)和上部件(UPC)；其中涡轮机内壳体(TMI)被设计为用于包括至少两个级(STG)的径向涡轮机(RTM)；其中涡轮机内壳体(TMI)在两个级(STG)之间分别具有一个回引级(BFC)；其中下部件(LPC)和/或上部件(UPC)至少部分地以跨越至少两个级(STG)的方式一体式形成。为了改进这种类型的涡轮机内壳体,提出了：下部件和/或上部件至少部分地以跨越至少两个级的方式一体式形成。(The invention relates to a turbine inner housing (TMI) for a Radial Turbine (RTM), wherein the turbine inner housing (TMI) has a joint (TF) along a longitudinal axis (X), in particular a joint (TF) along a rotor longitudinal axis (RX), such that the turbine inner housing (TMI) can be divided into a lower component (LPC) and an upper component (UPC); wherein the turbine inner casing (TMI) is designed for a Radial Turbine (RTM) comprising at least two Stages (STG); wherein the turbine inner casing (TMI) has a respective return stage (BFC) between the two Stages (STG); wherein the lower component (LPC) and/or the upper component (UPC) are formed integrally at least partially in such a way as to span at least two Stages (STG). In order to improve this type of inner turbine casing, it is proposed: the lower part and/or the upper part are formed integrally at least partially in such a way as to span at least two stages.)

1. A turbine inner casing (TMI) for a Radial Turbine (RTM),

wherein the inner turbine housing (TMI) has a joint (TF) along the longitudinal axis (X), in particular a joint (TF) along the rotor longitudinal axis (RX), so that the inner turbine housing (TMI) can be divided into a lower component (LPC) and an upper component (UPC);

wherein the turbine inner casing (TMI) is designed for a Radial Turbine (RTM) comprising at least two Stages (STG);

wherein the turbine inner casing (TMI) has one respective back-guiding stage (BFC) between two Stages (STG);

it is characterized in that the preparation method is characterized in that,

the lower component (LPC) and/or the upper component (UPC) are formed integrally at least partially in such a way as to span at least two Stages (STG).

2. The inner turbine casing (TMI) according to claim 1, wherein the inner turbine casing (TMI) consists of at most 50% metal.

3. The inner turbine housing (TMI) according to claim 2, wherein the inner turbine housing (TMI) is composed of at least 50 wt% of plastic.

4. A turbomachine inner casing (TMI) wherein a surface which in operation is exposed to a process fluid is at least partially provided with a coating (SCC).

5. The turbomachine inner casing (TMI) according to claim 4, wherein the coating (SCC) is at least partly composed of metal.

6. Turbine inner casing (TMI) according to at least one of claims 1 to 5,

wherein the inner turbine shell (TMI) has at least two back-guiding stages (BFC);

wherein said inner turbine housing (TMI) has an Outer Surface (OSC) and an Inner Surface (ISC) defining an interior of said inner turbine housing (TMI), wherein axially between two back-guiding stages (BFC), said Outer Surface (OSC) has at least one recess (RRZ) extending radially inwardly.

7. The inner turbine housing (TMI) according to claim 6, wherein the one or more recesses (RRZ) extend over a fraction of at least 35% of the cross-section of the inner turbine housing (TMI).

8. An installation (ARG) comprising a turbine inner casing (TMI) according to at least one of claims 1 to 7 and a turbine outer casing (TMO) surrounding the turbine inner casing (TMI), wherein the installation (ARG) has an axial low-pressure side (LPS) and an axial high-pressure side (HPS), wherein the installation (ARG) has a seal (STS), which seal (STS) extends in the circumferential direction and is arranged in the gap (RBT) between the high-pressure side (HPS) and the low-pressure side (LPS) such that the gap (RBT) is divided into a high-pressure part (HPC) and a low-pressure part (LPC).

9. An Apparatus (ARG) according to at least claims 5 and 8, wherein a plurality of said recesses (RRZ) is arranged on said axial High Pressure Side (HPS).

10. An Apparatus (ARG) according to claim 7 or 9, wherein the outer turbine housing (TMO) is designed as a barrel structure such that an engagement portion (OCS) is provided transversely to the longitudinal axis (X).

11. The Apparatus (ARG) according to claim 10, wherein the engagement portion (OCS) separates a cover portion (COV) from a barrel portion (BRL) of the outer turbine housing (TMO).

12. An inner turbine casing (TMI) according to at least one of claims 1 to 6 or an Apparatus (ARG) according to at least one of claims 8 to 11, wherein at least one section is manufactured by means of an additive manufacturing method, said at least one section being integrally formed in a manner spanning at least two Stages (STG).

Technical Field

The invention relates to a turbine inner casing for a radial turbine, wherein the turbine inner casing has a joint along a longitudinal axis, in particular a joint along a rotor longitudinal axis, such that the turbine inner casing can be divided into a lower part and an upper part, wherein the turbine inner casing is designed for a radial turbine comprising at least two stages, wherein the turbine inner casing has a return stage between the two stages, wherein the lower part and/or the upper part is formed in one piece at least partially across the at least two stages.

Background

Radial turbines of the above-mentioned type with a turbine inner casing of this type are already known from the publications WO2016026825-A1, WO2010034602-Al, WO2007137959-Al and EP 1860326-A1.

The inner casing of the turbine or of the turbine, in particular of the radial turbine, is always surrounded by an outer casing. Here, the outer housing is substantially sealed, so that no significant amount of process fluid can escape from the outer housing. If a shaft bore is provided in the outer housing, it is sealed by means of a shaft seal. Leaks caused by technical reasons may occur at these locations, but this is undesirable. In principle, it is also possible to arrange the drive for, for example, a compressor or a pump in the outer housing, so that no shaft bore is required. In this case, the respective seal of the outer housing is truly sealed.

In the sense of the present invention, a corresponding turbine serves for the transmission of technical work out of or onto a process fluid by means of a rotor, which extends along a rotor axis. The pressure of the process fluid is increased or decreased along the axial extension of the inner turbine casing, so that a significant pressure difference is generated in or across the turbine between the axial ends of the inner turbine casing. In the simplest case, the process fluid flows through the turbine from the inflow to the outflow. In principle, it is also possible to feed a partial flow or to branch off a partial flow between the inflow and outflow. In the case of radial turbines, in each individual impeller, a deflection of the flow from the axial direction to the radial direction, or vice versa, takes place.

In the sense of the term interpretation of the present application, a multistage design means an embodiment with a plurality of impellers (in the term interpretation of the present application one impeller corresponds to one stage), which have to realize a deflection from a radially outward flow direction to a radially inward flow direction. In the case of a compressor, the process fluid leaving the impeller in a radially outward flow must be reversed 180 degrees radially inward with respect to the flow direction and again fed substantially axially to the downstream impeller. For this purpose, radial turbines have so-called back-leading stages. Such return stages are usually bladed annular channels which comprise diffusers with radially outward flow directions and which realize a 180-degree reversal of the flow direction by means of a correspondingly embodied annular channel. Subsequently, the process fluid is directed radially inward. The diffuser and/or the radially inward return usually have guide vanes which divide an annular channel, which has been formed relatively complicatedly, into individual flow channels in the circumferential direction. For optimum aerodynamic performance, it is also desirable to construct the respective guide vanes three-dimensionally, which makes the geometric construction of these components or return stages extremely complex. At present, three-dimensional shaping of the return vane cannot or hardly be achieved by means of cutting work in conventional techniques. In particular, for assembly purposes, such a return stage or the turbine inner casing which is essentially composed of these return stages is usually divided into an upper part and a lower part along a joint parallel to the longitudinal axis. Furthermore, the conventional manufacture of such highly complex geometries requires that each individual return stage be axially divided into at least two axial sections which, in the assembled state, form the described annular channel. In this way, a conventional inner turbine casing is constructed from two axial stacks of individual return stage components that together form an upper component and a lower component, thereby forming a complete inner turbine casing. This modular construction is very complicated due to the large number of parts, which requires many fixing measures and sealing requirements. Furthermore, the various parts need not only to be sealed to each other, but also to be aligned with each other accordingly. In addition to the complicated manufacture of the annular return stage flow channel, the sealing surface and the large number of central bores and securing portions required are also very complicated and expensive to manufacture.

Disclosure of Invention

Based on the disadvantages described above, it is an object of the present invention to at least partly solve these problems. In order to achieve the object according to the invention, a turbine inner casing of the above-mentioned type is proposed with the additional features of the characterizing part of the independent claim. An apparatus having such a turbine inner casing is also proposed.

Unless otherwise specified, terms such as "axial", "radial", "circumferential" are used with respect to the longitudinal axis of the inner turbine casing, which is at least parallel to the rotor longitudinal axis of the respective radial turbine.

Unless otherwise stated, the description in this application refers to the design of a turbine equipped according to the invention as a compressor. Alternatively, the turbine equipped according to the invention can also be designed as an expander, without explicit reference. The person skilled in the art will be able to apply the present description of the invention to an expander with the necessary modifications according to his expert knowledge.

In the context of the present invention, the term "one-piece" is to be understood as meaning a component which is designed such that it cannot be separated in an intact manner and is therefore formed from a homogeneous piece of material, or which is designed at least in a material-fitting manner or at least in a form-fitting manner as a unit, such that it can no longer be separated in an intact manner.

The integral formation of the upper and/or lower part on at least one section of the inner turbine casing spanning two stages provides a significant stiffening of the structure, in particular because the guide vanes in the annular chamber or in the flow channel of the return stage of the inner turbine casing provide a composite construction which can withstand high loads. It is therefore particularly preferably provided that the return stage is embodied as a bladed return stage or as a return stage with guide vanes.

In particular, it is preferred that each return stage formed in one piece has a guide vane at least in the radially inwardly directed section (flow direction) and/or in the radially outwardly directed section (flow direction). As a result, not only is a particularly aerodynamically advantageous and efficient design ensured, but also a particularly high rigidity of the one-piece portion is ensured.

Advantageously, a further aspect of the invention provides that the turbine inner casing is composed of up to 50 wt.% metal. Particularly preferably, the turbine inner casing consists of up to 30 wt.% of metal. A particularly preferred development of the invention provides that the turbine inner casing consists of at least 50 wt.% of plastic, preferably 30 wt.% of plastic (unless otherwise stated, all percentage data relate to mass in the present application). Compared to conventional designs of the turbine inner casing, the design according to the invention makes the components of the turbine inner casing mainly made of plastic, since the one-piece design ensures mechanical rigidity, which otherwise could only be ensured by implementing the components with metal.

In order that the inner turbine casing is also sufficiently wear-resistant, it is advantageous if the surface which is exposed to the process fluid during operation is provided at least in regions with a coating which is more wear-resistant than the base material which is coated with the coating. Particularly advantageously, such a coating can be formed at least partially from metal or from a corresponding metal part or be provided by means of a metal inlay.

A particularly advantageous development of the invention provides that the turbine inner casing has at least two return stages, wherein the turbine inner casing has an outer surface and an inner surface which delimits the interior of the turbine inner casing, wherein axially between the two return stages the outer surface has at least one recess which extends radially inward. In the case of radial turbines, the part of the impeller which extends in such a way as to suck in the process fluid axially and deflect it radially is usually located axially between the annular flow channels of the return stage which are U-shaped in longitudinal section. In particular, the radially outer axial region is essentially non-functional aerodynamically in this region, since the annular channel of the return stage extends axially from the outflow of the impeller to the axial inflow of the downstream impeller (this statement on the flow direction applies to compressors, the flow direction being opposite for expanders; in the following, without further explanation, this statement on the flow direction always uses the example of a compressor). It is therefore advantageous to provide the axial region between the two return stages with a recess or groove extending radially inwards. Such a recess, depending on its size, considerably reduces the self-weight of the inner turbine housing and may, for example, continue radially inwards to the outer diameter of the impeller. Particularly preferably, the radially inner bottom of the respective recess is located in the region of the impeller outer diameter of the adjoining stage plus/minus 20% of the impeller outer diameter. Particularly preferably, one or more such recesses extend over at least a 35% portion of the cross section of the inner turbine casing. Here, 100% means an imaginary cross section which forms the average between two cross sections which are actually present in axially adjacent wheel regions of the inner turbine housing (the cross sections being arranged perpendicular to the longitudinal axis). In the case of a cylindrical turbine inner casing, the 100% cross-sectional portion is a constant cross-section. An important advantage of such a recess is that, at least in the region of the recess, the externally applied pressure acts in such a way that the axial length is not changed. In fact, without this recess, significant deformation of the upper and lower parts of the turbine inner casing may occur, depending on the rigidity of the turbine inner casing and on the pressure between the inner and outer casings. Such a recess thus reduces the requirements on the rigidity of the inner turbine casing.

The advantages according to the invention are particularly evident in a device comprising an inner turbine casing of the type according to the invention or a corresponding development and an outer turbine casing, wherein the device has an axial low-pressure side and an axial high-pressure side, wherein the device has a seal which extends in the circumferential direction and is arranged in a gap between the high-pressure side and the low-pressure side such that the gap is divided into a high-pressure part and a low-pressure part. Advantageously, the device is designed such that the high-pressure part is in operation at the exhaust pressure of the turbine and the low-pressure part is in operation at the intake pressure. In this case, it is particularly advantageous to arrange a plurality of recesses between two adjacent return stages in the region of the high-pressure section, so that, on the one hand, the high pressure is at least partially compensated for in the axial direction and, on the other hand, the resulting force distribution on the outer surface of the inner turbine casing ensures a particularly uniform contact pressure of the lower part of the inner turbine casing against the upper part during operation and therefore only minor measures are required between the two components for the purpose of fixing and sealing.

Particularly advantageously, the inner turbine housing of the device is designed as a barrel structure, so that the joint is arranged transversely to the longitudinal axis. Here, it is advantageous that the joint separates the cover part from the barrel part of the outer turbine housing. Here, a person skilled in the art may understand a "cover" as an axial end of the tub, which axial end does not have a housing function.

It is particularly advantageous to manufacture at least one section of the inner turbine casing by means of an additive manufacturing method (generative manufacturing method or additive production), such section being integrally formed in such a way that it spans at least two stages. Corresponding additive manufacturing processes are already known from WO2016/198210, WO2017/060036, WO2017/102286, WO2017/121539, WO2017/137376, WO2017/37262, WO2017/167615, WO2017/182220, WO2017/182221, WO2017/194274, WO2017/194451, WO2015/144401, WO2017/045823, WO2017/063861, WO2017/093461, WO2017/133812, WO2017/174234, WO2017/174233, WO2017/194387, WO2016/078800, WO2016/113107, WO2016/188696 and WO 2017/157620. In principle, all additive manufacturing methods may be used for the construction according to the invention, such as: selective Laser Melting (SLM), Selective Laser Sintering (SLS), Selective Heat Sintering (SHS), spray bonding (curing of powder material by means of binder), Electron Beam melting (Electron Beam melting ═ EBM), fused deposition modeling (FDM or Fused Filament Fabrication (FFF)), build-up or plating, Wax Deposition Modeling (WDM), contour engraving, metal powder application Method (MPA), cold injection and Electron Beam Welding (Electron Beam Welding ═ EBW), Stereolithography (SLA) + micro SLA, exposure method using Digital Light Processing (DLP), and composite liquid molding (LCM), layered solid molding (LOM), 3D screen printing of metals, and light-controlled electrophoretic separation.

An advantageous development of the invention provides that, in addition to the suction insert on the low-pressure side, the turbine inner housing is divided into a preferably one-piece lower part and a preferably one-piece upper part, the suction insert is preferably not divided in the circumferential direction, and the suction insert is combined with the lower part LPC and the upper part UPC in a manner substantially axially divided in the joint SPL into the turbine inner housing TMI. Preferably, a seal between the turbine inner casing and the turbine outer casing, which separates the high-pressure side from the low-pressure side, rests on the suction insert. The suction insert is advantageously made of metal in order to be able to withstand the mechanical loads caused by the pressure difference.

Here, selective laser melting, electron beam melting is particularly advantageous. In this case, it is particularly advantageous if not only at least the mentioned sections but also at least the entire upper part or the entire lower part, or both the upper part and the lower part, are formed in one piece. Thus, an additive manufacturing method of the type described above may advantageously be applied to the entire turbine inner casing.

Drawings

The present invention is explained in detail according to specific embodiments with reference to the drawings in the following. Wherein:

fig. 1 shows a schematic longitudinal section through a device or a radial turbine with an inner turbine shell according to the invention.

Detailed Description

Fig. 1 shows a device ARG or a radial turbine RTM with a turbine inner housing TMI according to the invention. The turbine inner casing TMI is surrounded by a turbine outer casing TMO through which the process gas PFL flows from the inflow IMF to the outflow EXT. In a particular embodiment of a radial turbocompressor, a higher pressure is applied to the process fluid PFL as it flows through the turbine inner casing TMI by means of impellers IMP which are part of a rotor ROT which rotates about the longitudinal axis X or rotor axis RX. Here, the turbine inner housing TMI is a static, in particular aerodynamically active structural element, and the rotor ROT with the impeller IMP introduces technical work into the process fluid PFL from an external drive which is not shown in detail. For the purpose of coupling the drive, the left-hand shaft end and the right-hand shaft end of the rotor are led out axially from the outer housing TMO at through bores. By means of a shaft seal, not explained in detail, the respective shaft bore is sealed with respect to a pressure difference between the process fluid in the interior of the outer housing TMO and the environment.

The turbine inner casing TMI receives the process fluid PFL in the turbine outer casing TMO in the region of the gap RBT. The gap RBT is divided into a high pressure side HPS and a low pressure side LPS by means of a seal STS between the turbine inner casing TMI and the turbine outer casing TMO. The seal STS extends in the circumferential direction (relative to the longitudinal axis X or the rotor axis RX) and separates the axial high-pressure portion HPC from the axial low-pressure portion LPC of the gap RBT. The inflow IMF of the outer turbine housing TMO opens into the low-pressure part LPC and the outflow EXT is connected in a fluid-conducting manner to the high-pressure part HPC. The seal STS is designed for axial abutment, so that in operation the higher pressure in the high-pressure part HPC pushes the turbine inner casing TMI in the direction of the low-pressure part LPC and, as a result, the contact over the entire circumference ensures the tightness of the seal STS.

The radial turbine RTM is shown with six wheels, so in the interpretation of terms according to the present invention, the radial turbine RTM has six stages STG or six compression stages. Between the two stages, a so-called back-guiding stage BFC is formed in the turbine inner casing TMI. The return stage receives the process fluid PFL flowing radially outward from the impeller IMP located upstream. In the section of the return stage BFC which is first used as a diffuser, the process fluid is decelerated and the undesired swirl component is removed as far as possible by the guide vanes arranged there. In the downstream section of the annular channel of the return stage BFC, the process fluid is deflected radially inward by 180 ° and then continues to be guided radially inward through the section fitted with guide vanes. Downstream, it is deflected 90 degrees in the axial direction with respect to the next impeller IMP located upstream. In a particular embodiment, the turbine inner casing TMI is designed as a combination of a one-piece lower part LPC and a one-piece upper part UPC with a joint along the longitudinal axis X. Similarly, the upper part UPC and the lower part LPC of the inner turbine casing may also be formed integrally only partly across at least two stages, and this may also apply only to the lower part LPC or the upper part UPC. This need not be further explained.

In a particular embodiment, the turbine inner housing TMI is divided into a lower part LPC and an upper part UPC, in addition to the air suction insert SES, which is not divided in the circumferential direction and which is combined with the lower part LPC and the upper part UPC into the turbine inner housing TMI by means of a substantially axial division in the joint SPL. A seal STS separating the high pressure side HPS from the low pressure side STS abuts the suction insert SES. In order to be able to withstand the mechanical loads from the pressure difference, the suction insert SES is advantageously made of metal.

In this embodiment, the turbine inner casing TMI consists of at most 50 wt% metal, preferably at most 30 wt% metal. Particularly preferably, the turbine inner casing consists of a mass fraction of 50 wt.% or more of plastic. The surfaces of the inner turbine casing which in operation are exposed to the process fluid PFL are locally provided with a coating SCC. The coating is at least partially composed of a metal.

The inner turbine shell defines an inner surface ISC and an outer surface OSC. Axially between the two back-extraction stages BFC, the outer surface OSC is provided with a radially inwardly extending recess RRZ, respectively. The recess RRZ accounts for at least 35% of the cross section of the turbine inner casing TMI. In operation, therefore, the exhaust gas pressure of the high-pressure side HPS also acts in the region of this recess RRZ, and on the one hand, it ensures that the axial compressive forces on the turbine inner casing TMI are small, and on the other hand, only small deformations thereby occur, and uniform contact of the sealing surfaces between the upper component UPC and the lower component LPC is ensured. The axial stiffening of the upper part UPC and the lower part LPC is achieved by means of ribs in the recesses RRZ, which ribs extend essentially in a planar manner in the axial-radial direction.

In operation, the pressure in the individual recesses in the region of the outer surface OSC is generally less than the exhaust pressure on the high-pressure side HPS. Due to the fine contour in the region of the outer surface OSC, this operating pressure acts such that the joint TF between the upper component UPC and the lower component LPC is compressed, thus preventing internal leakage. In conventional metal housings, the joining region is thick-walled and has residual gaps resulting from manufacturing, which leads to internal leakage.

The turbine outer housing TMO is designed as a barrel structure, so that the joints OCS are arranged on both sides in a manner transverse to the longitudinal axis X. Axially on both sides, the cover COV forms an axial closure of the barrel portion BRL of the outer turbine housing TMO. The cover part has no shell function and forms only an axial closure.

The turbine inner casing TMI is manufactured by means of an additive manufacturing method at least in the area, which is integrally formed in a manner spanning at least two stages.