Turbomachine inner housing

Abstract

A turbomachine inner housing for a radial turbomachine, wherein the turbomachine inner housing includes a partial joint along a longitudinal axis, in particular a rotor longitudinal axis, such that the turbomachine inner housing can be divided into a lower part and an upper part, wherein the turbomachine inner housing is designed for a radial turbomachine with at least two stages, wherein the turbomachine inner housing has a return stage in each case between two stages, wherein the lower part and/or the upper part is designed in one piece so as to span at least two stages at least in sections. In order to improve a turbomachine inner housing of this kind, the lower part and/or the upper part is designed in one piece so as span at least two stages at least in sections.

Claims

1. A turbomachine inner housing for a radial turbomachine, the turbomachine inner housing comprising: wherein the turbomachine inner housing has a dividing line along a longitudinal axis, or a rotor longitudinal axis, such that the turbomachine inner housing is divided into a lower part and an upper part, wherein the turbomachine inner housing is designed for a radial turbomachine comprising at least two stages, wherein the turbomachine inner housing has a return stage having a vaned guide section defined by guide vanes between two stages in each case, wherein the lower part and/or the upper part of the turbomachine inner housing, including the return stage having the vaned guide section defined by the guide vanes, is formed as one structural piece, over at least one section, spanning the at least two stages of the radial turbomachine, wherein the turbomachine inner housing has at least two return stages, wherein the turbomachine inner housing has an inner surface defining the inside of the turbomachine inner housing and an outer surface, wherein the outer surface has a plurality of recesses extending radially inwards axially between two return stages, wherein, during operation, the pressure in individual recesses of the plurality of recesses in the region of the outer surface is lower than the final pressure on a high pressure side.

2. The turbomachine inner housing as claimed in claim 1, wherein the turbomachine inner housing is made from up to 50% metal.

3. The turbomachine inner housing as claimed in claim 2, wherein the turbomachine inner housing is made from at least 50% plastic by weight.

4. The turbomachine inner housing as claimed in claim 1, wherein a surface which is exposed to a process fluid during operation is provided with a coating, at least in some regions.

5. The turbomachine inner housing as claimed in claim 4, wherein the coating is made at least partially from metal.

6. The turbomachine inner housing as claimed in claim 1, wherein the plurality of recesses extend over at least 35% of a cross-sectional area of the turbomachine inner housing.

7. An arrangement, comprising: a turbomachine inner housing as claimed in claim 1, and a turbomachine outer housing surrounding the turbomachine inner housing, wherein the arrangement has an axial low pressure side and an axial high pressure side, wherein the arrangement has a seal, which extends in a circumferential direction and is arranged in a space between the high pressure side and the low pressure side such that the space is divided into a high pressure part and a low pressure part.

8. The arrangement as claimed in claim 7, wherein the plurality of recesses are arranged on the axial high pressure side.

9. The arrangement as claimed in claim 8, wherein the turbomachine inner housing is formed in a barrel design such that a dividing line is provided transversely to the longitudinal axis.

10. The arrangement as claimed in claim 9, wherein the dividing line separates a cover from a barrel of the turbomachine housing.

11. The turbomachine inner housing as claimed in claim 1, wherein the at least one section is produced by means of an additive manufacturing method.

12. A turbomachine inner housing for a radial turbomachine, the turbomachine inner housing comprising: wherein the turbomachine inner housing has a dividing line along a longitudinal axis, or a rotor longitudinal axis, such that the turbomachine inner housing is divided into a lower part and an upper part, wherein the turbomachine inner housing is designed for a radial turbomachine comprising at least two stages, wherein the turbomachine inner housing has a return stage having a vaned guide section defined by guide vanes between two stages in each case, wherein the lower part and/or the upper part of the turbomachine inner housing, including the return stage having the vaned guide section defined by the guide vanes, is formed as one structural piece, over at least one section, spanning the at least two stages of the radial turbomachine, wherein the turbomachine inner housing has at least two return stages, wherein the turbomachine inner housing has an inner surface defining the inside of the turbomachine inner housing and an outer surface, wherein the outer surface has a plurality of recesses extending radially inwards axially between two return stages.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described in more detail below with the aid of a specific exemplary embodiment with reference to a drawing, which shows:

(2) FIG. 1 a schematic longitudinal section through an arrangement or a radial turbomachine with a turbomachine inner housing according to the invention.

DETAILED DESCRIPTION OF INVENTION

(3) FIG. 1 shows an arrangement ARG or a radial turbomachine RTM with a turbomachine inner housing TMI according to the invention. The turbomachine inner housing TMI is surrounded by a turbomachine outer housing TMO, through which a process gas PFL flows from an inflow IMF to an outflow EXT. In the specific exemplary embodiment of a radial turbocompressor, the process fluid PFL is subjected to a relatively high pressure when flowing through the turbomachine inner housing TMI by means of impellers IMP, which are a constituent part of a rotor ROT rotating about a longitudinal axis X or rotational axis RX. The turbomachine inner housing TMI here is a static, in particular aerodynamically-acting component and the rotor ROT with the impellers IMP introduces technical energy from an outer drive (not illustrated in more detail) into the process fluid PFL. For the purpose of connecting a drive, the left shaft end, like the right shaft end, of the rotor is guided axially out of the outer housing TMO at a through-opening. The corresponding shaft openings are sealed by means of a shaft seal (not explained in more detail) with respect to the pressure difference between the process fluid inside the outer housing TMO and the environment.

(4) The turbomachine inner housing TMI receives the process fluid PFL in the turbomachine outer housing TMO within a space RBT. The space RBT is divided into a high pressure side HPS and a low pressure side LPS by means of a seal STS between the turbomachine inner housing TMI and the turbomachine outer housing TMO. The seal STS extends in the circumferential direction (with respect to the longitudinal axis X or rotor axis RX) and separates an axial high pressure part HPC of the space RBT from an axial low pressure part LPC. The inflow IMF of the turbomachine outer housing TMO leads into the low pressure part LPC and the outflow EXT is in fluid-conducting communication with the high pressure part HPC. The seal STS is designed for axial contact, so that, during operation, the higher pressure in the high pressure part HPC pushes the turbomachine inner housing TMI in the direction of the low pressure part LPC and, accordingly, the full circumferential contact ensures the leak-tightness of the seal STS.

(5) The radial turbomachine RTM shown has six impellers and therefore, in the interpretation according to the invention, six stages STG or compressor stages. A so-called return stage BFC in the turbomachine inner housing TMI is formed between two stages in each case. The return stage receives the process fluid PFL flowing radially outwards from the impeller IMP located upstream. In the section of the return stage BFC which acts firstly as a diffusor, the process fluid is slowed down and substantially freed of undesired swirl components by guide vanes provided there. In the section of the annular channel of the return stage BFC which is located downstream, the process fluid is deflected radially inwards through 180° and then continues radially inwards through a section equipped with guide vanes. Downstream, a 90 degree deflection in the axial direction to the next impeller IMP located upstream takes place. In the specific exemplary embodiment, the turbomachine inner housing TMI is designed as a combination of a one-piece lower part LPC and a one-piece upper part UPC with a dividing line along a longitudinal axis X. Similarly, the upper part UPC and the lower part LPC of the turbomachine inner housing can also be formed in one piece, also spanning at least two stages only in some sections, and this can also be the case for only the lower part LPC or the upper part UPC. This needs no further illustration.

(6) In the specific exemplary embodiment, the division of the turbomachine inner housing TMI into a lower part LPC and an upper part UPC is realized with the exception of a suction insert SES, which, undivided by a substantially axial division in the circumferential direction, is combined with the lower compartment LPC and the upper compartment UPC at a dividing line SPL to form the turbomachine inner housing TMI. The seal STS, which separates the high pressure side HPS from the low pressure side LPS, lies against the suction insert SES. The suction insert SES is advantageously made from metal here, so that it is able to absorb the mechanical load resulting from the pressure difference.

(7) In the exemplary embodiment, the turbomachine inner housing TMI is made from up to 50% metal by weight, advantageously up to 30% by weight. The turbomachine inner housing is particularly advantageously formed from 50%, or more than 50%, plastic by weight. In some regions, the turbomachine inner housing is provided with a coating SCC on surfaces which are exposed to the process fluid PFL during operation. This coating is made at least partially of metal.

(8) The turbomachine inner housing defines an inner surface ISC and an outer surface OSC. The outer surface OSC is provided with a recess RRZ extending radially inwards axially between two return stages BFC in each case. This recess RRZ accounts for at least 35% of the cross-sectional area of the turbomachine inner housing TMI. Accordingly, during operation, the final pressure of the high pressure side HPS also acts in the region of these recesses RRZ and ensures, on the one hand, a relative low axial compressing force on the turbomachine inner housing TMI and, on the other, only a slight resultant deformation and a uniform contact of a sealing surface between the upper part UPC and the lower part LPC. Axial reinforcement of the upper part UPC and the lower part LPC is achieved by means of ribs in the recesses RRZ, which extend substantially in the axial-radial direction in a planar manner.

(9) The pressure in the individual recesses in the region of the outer surface OSC during operation is generally lower than the final pressure on the high pressure side HPS. Owing to the intricate contour in the region of the outer surface OSC, this operating pressure acts in such a way that the dividing line TF between the upper part UPC and the lower part LPC is compressed to prevent internal leaks. In a conventional metal housing, the joining regions are thick-walled with remaining production-related gaps, which result in internal leaks.

(10) The turbomachine outer housing TMO is formed in a barrel design in such a way that a dividing line OCS is provided on both sides, transversely to the longitudinal axis X in each case. A cover COV forms an axial termination of a barrel BRL of the turbomachine outer housing TMO axially on both sides. The cover does not have a casing function and merely forms the axial termination.

(11) The turbomachine inner housing TMI has been produced by means of an additive manufacturing method, at least in the region in which at least two stages are comprehensively formed in one piece.