Radial regulator

Abstract

Radial expansion valve. The invention relates to a radial expansion valve for expanding a process gas, having a housing and a rotor (10) mounted in the housing and comprising multiple blades (12), the blades (12) of the rotor (10), together with a radially internal hub contour (16) of a hub (11) of the rotor (10) and a radially external housing contour (17) of the housing, defining flow channels (13) for the process gas, into which the process gas to be expanded enters in the radial direction or substantially in the radial direction and out of which the expanded process gas exits in the axial direction or substantially in the axial direction, the radially internal hub contour (16) of the rotor (10) comprising a change in curvature at least at certain circumferential positions viewed in the meridional section such that, adjacent to a flow-leading side of the rotor,The radially inner hub contour (16), seen in the meridian section, is curved radially outwards and, adjacent to a flow leakage side of the rotor, the radially inner hub contour (16), seen in the meridian section, is curved radially inwards. Figure for the abbreviation: Figure 1,

Description

Title of the invention: Radial regulator

[0001] The invention relates to a radial pressure regulator.

[0002] Essentially, expansion valves and compressors are differentiated in turbomachinery. Expansion valves are also called turbines and serve to expand a process gas in order to extract energy during the expansion of the process gas. Compressors compress a process gas using energy. The present invention relates to an expansion valve, namely a radial expansion valve.

[0003] Radial expansion valves known in practice are equipped with a housing and a rotor mounted in the housing, the rotor comprising multiple blades. Together with a radially inner hub contour of the rotor and a radially outer housing contour of the housing, the rotor blades define flow channels for the process gas. The process gas to be expanded enters these flow channels in the radial direction or substantially in the radial direction. The expanded process gas exits these flow channels in the axial direction or substantially in the axial direction.

[0004] In order to produce a radial expansion valve with the highest possible efficiency, it is desirable to reduce the secondary flows in the flow channels. This ensures better flow through the flow channels. When an assembly for additional regulation of the expanded process gas, for example a diffuser, is arranged downstream of the radial expansion valve, the efficiency of the diffuser can also be increased by reducing the secondary flows in the radial expansion valve.

[0005] Starting from this, the present invention is based on the problem of creating a new type of radial expansion valve with reduced secondary flow.

[0006] This problem is solved by a radial expansion valve according to the invention. According to the invention, the radially inner hub contour of the rotor includes a change in curvature seen in the meridional section at least at certain circumferential positions such that, adjacent to a flow inlet side of the rotor, the radially inner hub contour, seen in the meridional section, is curved radially outward and, adjacent to a flow outlet side of the rotor, the radially inner hub contour, seen in the meridian section, is curved radially inward. Thanks to the invention, a radial expansion valve can be produced in which secondary flows, in particular secondary flows in the vertical direction and thus the radial direction of the rotor flow channels, can be reduced. In particular, The flow through the hub region can be improved. The radial expansion valve offers increased efficiency.

[0007] Preferably, the change in curvature is the only change in curvature of the radially inner hub contour.

[0008] Preferably, the change in curvature, at the circumferential positions where the radially inner hub contour of the rotor, in the meridian section, includes the change in curvature, is located within a range between 5% and 45% of the effective length of the radially inner hub contour. This profiling of the radially inner hub contour is particularly preferred for improved flow through the hub region of the radial expander in order to ultimately increase the efficiency of the radial expander.

[0009] Preferably, a minimum radius of curvature of the inwardly radially curved portion of the hub contour, at the circumferential positions where the radially inward hub contour of the rotor, viewed in the meridian section, includes the change in curvature, is between 5% and 30%, preferably between 10% and 15% of the effective length of the radially inward hub contour after the change in curvature. This feature also serves to improve the flow through the hub region of the radial expander to increase efficiency.

[0010] Preferably, a ratio between the radius of curvature of the portion of the hub contour curved radially outwards and the radius on the hub side of a flow inlet edge of the blades, at the circumferential positions in which the radially inner hub contour of the rotor, seen in the meridian section, includes the change of curvature, is greater than 1. In this way, the flow in particular through the hub region can be further improved while avoiding secondary flows.

[0011] Preferably, a ratio between the minimum radius of curvature of the portion of the hub contour curved radially inwards and the hub-side radius of a flow inlet edge of the blades, at the circumferential positions in which the radially inward hub contour of the rotor, seen in the meridian section, includes the change of curvature, is less than 2. In this way, the flow through the hub region while avoiding secondary flows can also be further improved.

[0012] According to a first embodiment, the radially inner hub contour of the rotor, viewed in the meridional section, is profiled differently in the circumferential direction. In particular, when the rotor hub contour, viewed in the circumferential direction, is profiled differently, this is achieved asymmetrically around the circumference. Here, a peak curved radially outwards in the flow channel and a trough curved radially inwards are These vortices are preferably formed between two adjacent blades in the circumferential direction, and in this way, in particular, the formation of horseshoe and channel vortices, each representing a secondary flow phenomenon, can be effectively countered. By using asymmetrical profiling around the circumference of the hub contour, the flow through the flow channels, especially in the hub region, can be further improved, and the efficiency of the radial expansion valve can be increased even further.

[0013] According to a second embodiment, the radially inner hub contour of the rotor, viewed in the meridian section, is profiled identically in all circumferential positions. In particular, when viewed in the circumferential direction, the inner hub contour is profiled identically in all circumferential positions, the hub contour is formed symmetrically around the circumference.

[0014] Other preferred developments of the invention are obtained from the above embodiments and the following description. Illustrative embodiments of the invention are explained in more detail, without limitation, with reference to the drawing. The figures represent:

[0015] [Fig.1]: a perspective view of a radial regulator;

[0016] [Fig.2]: a meridian section through the radial expander;

[0017] [Fig.3]: multiple meridian sections through the radial expander between two adjacent blades in the circumferential direction with an asymmetrical hub contour on the circumference.

[0018] A radial expansion valve, which can also be called a radial turbine, is used to expand a process gas in order to extract energy during the expansion of the process gas.

[0019] A radial expansion valve is equipped with a housing and a rotor mounted for rotation in the housing.

[0020] Figure 1 illustrates a rotor 10 of a radial expansion valve, the rotor 10 comprising a hub body 11 and multiple blades 12 spaced apart from each other viewed in the circumferential direction U connected to the hub body 11. Between two respective adjacent blades 12 in the circumferential direction U is formed a respective flow channel 13 for the process gas.

[0021] The blades 12 have flow leading edges 14 and flow trailing edges 15. In the region of the flow leading edges 14, the process gas to be expanded enters a respective flow channel 13 in the radial direction R or substantially in the radial direction R. The expanded process gas exits the respective flow channel 13 in the axial direction or substantially in the axial direction A.

[0022] Figure 2 illustrates a meridian section through the rotor 10, the invention concerning the profiling of the radially internal hub contour 16 of the rotor 10 seen in the meridian section.

[0023] In addition, the radially external housing contour 17 of the radial regulator and the orientation of a flow leading edge 14 and a flow trailing edge 15 of a blade 12 are illustrated in [Fig.2].

[0024] According to [Fig. 2], the flow leading edge 14 is positioned obliquely with respect to the axial direction A and the radial direction R such that an intersection point Si of the flow leading edge 14 with the hub contour 16 is located on a radius ri that is smaller than the radius ra, on which an intersection point Sa of the flow leading edge 14 with the housing contour 17 is located. The radius ri corresponds to the radius on the hub side of the flow leading edge 14.

[0025] It is further illustrated in [Fig. 2] that an intersection point Sx of the flow trailing edge 15 with the radially inner hub contour 16 has a shorter distance in the axial direction A relative to the intersection points Si and Sa than the intersection point Sy of the flow trailing edge 15 with the radially outer housing contour 17. In other embodiments, the intersection point Sx of the flow trailing edge 15 with the inner hub contour 16 may also be located at the same distance or at a greater distance in the axial direction A relative to the intersection points Si and Sa than the intersection point Sy of the flow trailing edge 15 with the radially outer housing contour 17.

[0026] Such a radial regulator is also called a diagonal regulator.

[0027] According to the invention, the radially inner hub contour 16 of the rotor 10 is profiled in certain circumferential positions seen in the meridian section in such a way that the hub contour 16 in these circumferential positions, seen in the meridian section, includes a change of curvature in such a way that, adjacent to the flow leading side of the rotor 10 or the flow leading edge 14 of the blades 12, the radially inner hub contour 16, seen in the meridian section, is curved radially outwards and, adjacent to the flow trailing side of the rotor 10 or the flow trailing edge 15 of the blades 12, seen in the meridian section, is curved radially inwards.

[0028] The radially internal hub contour 16 includes the change of curvature seen in the direction of travel of the latter between the intersection points Si and Sx, the change of curvature at the inflection point WP being positioned between the portion of the hub contour 16 curved radially outwards and the portion of the contour curved radially inwards.

[0029] The outward radial curvature of the hub contour 16 adjacent to the flow-inward side of the rotor 10 is represented in [Fig. 2] by the radius r1. The inward radial curvature of the hub contour 16 adjacent to the flow-outward side is represented in [Fig. 2] by the radius r2.

[0030] It should be noted that, viewed in the useful length or the direction of travel of the hub contour 16, the radius rl starting from the point of intersection Si changes, in the same way that the radius r2 seen from the point of inflection WP in the direction of the point of intersection Sx changes.

[0031] In each position of the useful length of the radially internal hub contour 16, an individual radius rl or r2 may be present, the radially internal hub contour 16 not being curved at the inflection point WP in order to produce the change in curvature.

[0032] At such circumferential positions of the rotor 12 in which the hub contour 16, seen in the meridian section, includes the change of curvature, the inflection point WP and thus the change of curvature are located in a range between 5% and 45% of the useful length of the radial hub contour 16 between the intersection point Si and the intersection point Sx, the intersection point Si being located at 0% of the useful length and the intersection point Sx at 100% of the useful length of the radially inner hub contour 16.

[0033] Furthermore, it is provided that at the circumferential positions of the rotor 10 in which the radially inner hub contour 16, seen in the meridian section, includes the radius of curvature, a ratio between the radius of curvature rl of the portion of the hub contour 16 curved radially outwards and the radius ri on the hub side of the point of intersection of the flow leading edge 14 with the hub contour 16 is greater than 1. Thus: rl / ri > 1 applies.

[0034] Furthermore, it is provided that at the circumferential positions of the rotor 10 in which the radially internal hub contour 16, seen in the meridian section, includes the change of curvature, a ratio between a minimum radius of curvature r2 MIN of the portion of the hub contour 16 curved radially inwards and the radius ri on the hub side of the point of intersection of the flow leading edge 14 with the hub contour 16 is less than 2. Thus: r2 MIN / ri < 2 applies.

[0035] As already explained, the inflection point WP, and therefore the change in curvature, is positioned between 5% and 45% of the effective length of the radially inwardly curved hub contour 16, between the outwardly curved hub contour 16 and the inwardly curved hub contour 16. As also already explained, the respective radius of curvature rl, r2 of the curvature of the hub contour 16 changes both upstream and downstream of the inflection point WP.

[0036] It is preferably provided that the minimum radius of curvature r2 MIN downstream of the inflection point WP, in which the hub contour 16 is curved radially inwards, is located between 5% and 30% of the useful length after the inflection point WP.

[0037] As already explained, the hub contour 16 comprises the above profiling exhibiting the change in curvature at least at certain circumferential positions viewed in the meridian section. According to a variant of the invention, the radially inner hub contour 16 of the rotor 10, viewed in the meridian section, is profiled identically in the circumferential direction in all circumferential positions. This then leads to a symmetrical profiling of the radially inner hub contour 16 around the circumference in the circumferential direction.

[0038] According to a second embodiment of the invention, the radially inner hub contour 16 of the rotor 10, seen in the meridian section, is profiled differently in the circumferential direction. Preferably, this is carried out in such a way that between two adjacent blades 12 in the circumferential direction, the radially inner hub contour 16, seen in first meridian sections, includes the change in curvature described above and, seen in second meridian sections, does not include any change in curvature, namely with radii of curvature each changing in the circumferential direction, so that between two adjacent blades 12 in the circumferential direction a peak curved radially outwards and a trough curved inwards are formed on the radially inner hub contour 16.In meridional sections without a change in curvature, the radially internal hub contour 16 is continuously curved radially inwards, i.e., with a radius of curvature that changes in the direction of travel. Figure 3 illustrates multiple radially internal hub contours 16 between two blades 12 of meridional sections spaced in the circumferential direction. Portions of the hub contour 16 on the flow-leading side that are radially curved outwards define the respective peak, and portions of the hub contour 16 that are radially curved inwards define the respective trough. The troughs and peaks seen in the direction of travel of the radially internal hub contour 16 are formed adjacent to the flow-leading side.

[0039] In particular, when viewed in the circumferential direction, the radially inner hub contour 16 changes in the meridional section. Preferably, between two adjacent blades in the circumferential direction, the ratio rl / ri between the radius of curvature rl of the portion of the hub contour 16 curved radially outwards and the radius ri on the hub side of the flow leading edge 14 of the blade 12 and / or the ratio r2 / ri between the radius of curvature r2 of the portion of the contour The hub 16 is radially curved inwards, and the radius ri on the hub side of the flow leading edge 14 of the blades 12 changes, and / or the position of the change in curvature, and thus of the inflection point WP, between the curves along the effective length of the radially inward hub 16 contour, each changes by a maximum of 15%. In this case, it is further provided that the radially inward hub 16 contour of the rotor 10 is repeated cyclically in each case between two blades 12 that are adjacent in the circumferential direction. Consequently, a peak and a trough are formed adjacent to the flow leading edge between two respective adjacent blades.

[0040] The radial expansion valve according to the invention, whether having a hub contour profiled symmetrically around the circumference or a hub contour profiled asymmetrically around the circumference, has high efficiency because, in particular, secondary flows in the direction of the height of the flow channels between the blades 12 can be reduced. In particular, there is improved flow through the hub region of the flow channels 13. Especially in the case of a radial expansion valve having a hub contour profiled asymmetrically around the circumference, secondary flow phenomena such as horseshoe vortices and channel vortices can be reduced.

[0041] List of reference numbers 10 Rotor 11 Hub 12 Pale 13 Drainage channel 14 Flow leading edge 15 Flow trailing edge 16 Hub contour 17 Casing outline

Claims

Demands

1. A radial expansion valve for expanding a process gas, having a housing with a rotor (10) mounted in the housing and comprising multiple blades (12), the blades (12) of the rotor (10), together with a radially internal hub contour (16) of a hub (11) of the rotor (10) and a radially external housing contour (17) of the housing, defining flow channels (13) for the process gas, into which the process gas to be expanded enters in the radial direction or substantially in the radial direction and from which the expanded process gas exits in the axial direction or substantially in the axial direction, in which the radially internal hub contour (16) of the rotor (10) comprises a change in curvature at least at certain circumferential positions viewed in the meridional section in such a manner that, adjacent to a flow-leading side of the rotor,The radially inner hub contour (16), viewed in the meridian section, is radially outward curved and, adjacent to a flow leakage side of the rotor, the radially inner hub contour (16), viewed in the meridian section, is radially inward curved, characterized in that at the circumferential positions at which the radially inner hub contour (16) of the rotor (10), viewed in the meridian section, includes the change of curvature, a minimum radius of curvature (r2-MIN) of the portion of the hub contour (16) radially inward curved is between 5% and 30%, preferably between 10% and 15% of the effective length of the radially inner hub contour after the change of curvature.

2. Radial regulator according to claim 1, characterized in that the change in curvature is a single change in curvature.

3. Radial regulator according to claim 1 or 2, characterized in that at the circumferential positions in which the radially inner hub contour (16) of the rotor (10) includes the change in curvature in the meridian section, the change in curvature is located in a range between 5% and 45% of the useful length of the radially internal hub contour (16).

4. Radial regulator according to claim 1, 2 or 3, characterized in that at the circumferential positions in which the radially inner hub contour (16) of the rotor, seen in the meridian section, includes the change in curvature, a ratio between the radius of curvature (rl) of the portion of the hub contour (16) curved radially outwards and the hub-side radius (ri) of a flow leading edge (14) of a blade (12) is greater than 1.

5. Radial regulator according to any one of claims 1 to 4, characterized in that at the circumferential positions in which the radially inward hub contour (16) of the rotor (10), seen in the meridian section, includes the change in curvature, a ratio between a minimum radius of curvature (r2-MIN) of the portion of the hub contour (16) curved radially inward and the hub-side radius (ri) of a flow leading edge (14) of a blade (12) is less than 2.

6. Radial regulator according to any one of claims 1 to 5, characterized in that the radially internal hub contour (16) of the rotor, seen in the meridian section, is profiled differently in the circumferential direction.

7. Radial regulator according to claim 6, characterized in that the radially inner hub contour (16) of the rotor, seen in the meridian section, is profiled differently in the circumferential direction in such a way that between two adjacent blades (12) in the circumferential direction, the radially inner hub contour (16) of the rotor (10), seen in first meridian sections, includes the change in curvature and, seen in second meridian sections, does not include any change in curvature, so that between two respective adjacent blades (12) in the circumferential direction a peak curved radially outwards and a trough curved radially inwards are formed.

8. Radial regulator according to claim 6 or 7, characterized in that the radially inner hub contour (16) of the rotor, seen in the meridian section, is profiled differently in the circumferential direction in such a way that between two adjacent blades (12) in the circumferential direction, the ratio between the radius of curvature (rl) of the portion of the hub contour (16) curved radially outwards and the radius (ri) hub side of a flow leading edge (14) of the blades changes.

9. Radial regulator according to any one of claims 6 to 8, characterized in that the radially inward hub contour (16) of the rotor, seen in the meridian section, is profiled differently in the circumferential direction in such a way that between two adjacent blades (12) in the circumferential direction, the ratio between the radius of curvature (r2) of the portion of the hub contour (16) curved radially inward and the radius (ri) hub side of a flow leading edge (14) of the blades changes.

10. Radial regulator according to any one of claims 6 to 9, characterized in that the radially inner hub contour (16) of the rotor, seen in the meridian section, is profiled differently in the circumferential direction in such a way that the position of the change of curvature changes by a maximum of 15% along the useful length of the radially inner hub contour (16).

11. Radial regulator according to any one of claims 6 to 10, characterized in that the radially internal hub contour (16) of the rotor between two respective adjacent blades (12) in the circumferential direction has a peak and a trough formed adjacent to the flow attack side of the rotor between these two respective adjacent blades.

12. Radial regulator according to any one of claims 1 to 5, characterized in that the radially internal hub contour (16) of the rotor, seen in the meridian section, is profiled similarly in all circumferential positions.

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