Abstract
A turbomachine, in particular a steam turbine, has a shield and a coolant supply which causes cold intermediate superheater steam to flow onto the rotor, wherein additionally supply holes are arranged in the shield, which holes bring part of the hot inflow steam into the cooling region between the shield and the rotor, in order to thus improve mixing so as to raise the temperature of the rotor at this thermally loaded point, such that in the event of a fault (e.g., failure of the coolant line) the resulting change in temperature is moderate.
Claims
1. A turbomachine, comprising: an inlet region for feeding steam, a rotatably mounted rotor, a casing, which is arranged around the rotor, wherein a flow passage is formed between the rotor and the casing, wherein the flow passage and the inlet region are fluidically interconnected, having a shield which is designed in such a way that during operation steam which flows into the inlet region is deflected into the flow passage, wherein the shield has a cooling medium feed which is designed in such a way that during operation cooling steam flows into a cooling region which is arranged between the shield and the rotor, and wherein the shield has a line which creates a fluidic connection between the cooling region and the inlet region.
2. The turbomachine as claimed in claim 1, wherein the turbomachine is of double-flow design.
3. The turbomachine as claimed in claim 2, wherein during operation steam which flows into the inlet region is deflected by the shield partly into a first flow and partly into a second flow.
4. The turbomachine as claimed in claim 1, wherein the shield is arranged upstream of a first blade stage.
5. The turbomachine as claimed in claim 1, wherein the shield is arranged around the rotor.
6. The turbomachine as claimed in claim 1, wherein the cooling medium feed is designed in such a way that during operation the cooling steam impinges radially upon the rotor.
7. The turbomachine as claimed in claim 1, wherein the cooling medium feed is designed in such a way that during operation the cooling steam impinges tangentially upon the rotor.
8. The turbomachine as claimed in claim 1, wherein the line is designed in such a way that during operation steam from the inlet region impinges radially upon the rotor.
9. The turbomachine as claimed in claim 1, wherein the line is designed in such a way that during operation steam from the inlet region impinges tangentially upon the rotor.
10. The turbomachine as claimed in claim 1, further comprising: a cooling medium line which is directly connected to the cooling medium feed, wherein during operation the cooling steam flows in the cooling medium line.
11. A steam power plant having a turbomachine as claimed in claim 1, wherein the cooling medium feed is connected to a cool reheat line.
12. The turbomachine as claimed in claim 1, wherein the turbomachine is a steam turbine.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In the drawing
[0024] FIG. 1 shows a schematic view of a steam power plant
[0025] FIG. 2 shows a schematic view of the invention during operation
[0026] FIG. 3 shows a schematic view of the invention in the event of failure of the cooling medium feed
[0027] FIG. 4 shows a side view of the arrangement according to the invention
[0028] FIG. 5 shows a side view of the arrangement according to the invention in an alternative embodiment.
DETAILED DESCRIPTION OF INVENTION
[0029] FIG. 1 shows a steam power plant 1 in a schematized overview. The steam power plant 1 comprises a high-pressure turbine section 2 which has a live steam feed 3 and a high-pressure steam outlet 4. Live steam from a live steam line 5 flows through the live steam feed 3, wherein the live steam was produced in a steam generator 6. Arranged in the live steam line 5 is a live steam valve 7 which controls the flow of live steam through the high-pressure turbine section 2. Also arranged in the live steam line 5 is a stop valve (not shown) which closes off the steam feed to the high-pressure turbine section 2 in the event of a failure. After steam has flown through the high-pressure turbine section 2, during which the steam in the high-pressure turbine section 2 converts the thermal energy into rotational energy of the rotor 21, the steam flows out of the high-pressure steam outlet 4 into a cold reheat line 8. The steam in the cold reheat line 8 in comparison to the steam parameters of the live steam in the live steam line 5 is such that this cold reheat steam can be used as cooling medium, which is shown schematically in FIG. 1 by means of the cooling medium line 9. The cold reheat steam is heated in a reheater 10 and via a hot reheat line 11 conducted to an intermediate-pressure turbine section 12. The cooling medium line 9 can be directed to the intermediate-pressure turbine section 12 into the inlet region (not shown). The rotor of the intermediate-pressure turbine section 12 is connected with torque transmitting effect to the rotor of the high-pressure turbine section 2 and also to the rotor 21 of a low-pressure turbine section 13. Similarly, an electric generator 14 is connected with torque transmitting effect to the rotor 21 of a low-pressure turbine section 13. After the steam has flown through the intermediate-pressure turbine section 12, the steam flows out of the intermediate-pressure steam outlets 15 to the low-pressure turbine section 13. The intermediate-pressure turbine section 12 selected in FIG. 1 comprises a first flow 29 and a second flow 30. The steam is conducted out of the intermediate-pressure steam outlets 15 in a crossover line 16 to the low-pressure turbine section 13. After flowing through the low-pressure turbine section 13, the steam flows into a condenser 17 and is condensed there, forming water. The steam which is converted in the condenser 17, forming water, then flows via a line 18 to a pump 19 and from where the water is conducted to the steam generator 6.
[0030] The high-pressure turbine section 2, the intermediate-pressure turbine section 12 and the low-pressure turbine section 13 together are referred to as a steam turbine and constitute an embodiment of a turbomachine.
[0031] In FIG. 2, a view of the arrangement according to the invention is to be seen. FIG. 2 shows in particular an inlet region 20 of the intermediate-pressure turbine section 12. The intermediate-pressure turbine section 12 comprises a rotor 21 which is rotatably mounted around a rotational axis 22. The rotor 21 comprises a plurality of rotor blades 23 which are arranged in slots (not shown) on the rotor surface 24. Arranged between the rotor blades 23 are stator blades 25 which are retained on a casing (not shown). A first stator blade row 26 is designed in such a way that this stator blade row 26 supports a shield 27. The shield 27 is designed in such a way that during operation steam which flows into the inlet region 20 can be deflected into a flow passage 28. Since the intermediate-pressure turbine section 12 shown in FIG. 2 has a first flow 29 and a second flow 30, the flow passage 28 is divided into a first flow passage 31 and a second flow passage 32. The inflowing steam 33 is therefore deflected forming a first steam 34 and a second steam 35. The first steam 34 flows into the first flow passage 31. The second steam 35 flows into the second flow passage 32.
[0032] The intermediate-pressure turbine section 12 comprises a casing (not shown) which is arranged around the rotor 21, wherein the first flow passage 31 and the second flow passage 32 are formed between the rotor 21 and the casing, wherein the first flow passage 31 and the second flow passage 32 are fluidically connected to the inflow region 20.
[0033] A flow medium which in addition to steam can be ammonia or a steam-CO.sub.2 mixture is to be understood by the term steam.
[0034] The shield 27 has a cooling medium feed 36 which is designed in such a way that during operation cooling steam flows into a cooling region 37 which is arranged between the shield 27 and the rotor 21. Used as cooling steam is steam from the cooling medium line 9 which comes from the cold reheat line 8. Other cooling steam can be used in alternative embodiments. The cooling steam therefore flows out the cooling medium feed 36 onto the rotor surface 24 and cools a thermally stressed region which is represented by means of a parabolic gray area 38. The temperature is represented in shades of gray. As is to be seen in FIG. 2, the shade of gray in the parabolic gray area 38 is a little darker than the shades of gray of the rotor 21. This means that the temperature in the parabolic gray area 38 is higher than the temperature of the rotor 21.
[0035] In addition to the cooling medium feed 36, a line 39 is now arranged according to the invention in the shield 27. This line 39 creates a fluidic connection between the cooling region 37 and the inlet region 20. The line 39 can be constructed as a hole or as a plurality of holes. These holes can be constructed in a distributed manner on the circumference. The line 39 can be arranged symmetrically to the parabolic gray area 38, which means that the line 39 is arranged in the direction of a central inflow direction 40. In FIG. 2, the line 39 is not shown in the same direction as the central inflow direction 40 but shown a small distance further to the right.
[0036] FIG. 3 shows in the main the same arrangement as in FIG. 2. A repeat of the description and principle of operation of the components is therefore dispensed with. The difference in the view of FIG. 3 lies in the fact that a failure of the cooling medium feed 36 is symbolized by a cross. The failure of the cooling medium feed 36 leads to a heating up of the cooling region 37. This leads to a change of the temperature in the parabolic gray area 38. In FIG. 3, it is to be seen that the shades of gray are darker compared with the gray area in FIG. 2. This means that the temperature is increased compared with the normal operation which is to be seen in FIG. 2. Nevertheless, the temperature difference between the normal operation, as is to be seen in FIG. 2, and the failure operation which is shown in FIG. 3, is moderate. This means that the material of the rotor 21 experiences a comparatively small temperature jump.
[0037] FIG. 4 shows a side view of the arrangement according to the invention. The cooling medium feed 36 in a first embodiment is designed in the radial direction 41 toward the rotational axis. This means that during operation the cooling steam impinges radially upon the rotor 21. Similarly, the line 39 according to FIG. 4 is designed in such a way that during operation steam from the inlet region impinges radially upon the rotor 21.
[0038] FIG. 5 shows an alternative embodiment to the embodiment according to FIG. 4. FIG. 5 shows that the cooling medium feed 36 is designed in such a way that during operation the cooling steam impinges tangentially upon the rotor 21. To this end, the cooling medium feed 36 is basically constructed in such a way that the shield has a hole through which the steam can impinge tangentially upon the rotor 21. This leads to a swirl of the steam which is present in the cooling region 37. The line 39 is similarly designed in an alternative embodiment in such a way that during operation steam from the inlet region 20 impinges tangentially upon the rotor 21. This leads to a better mixing in the cooling region 37.
[0039] Although the invention has been fully illustrated and described in detail by means of the preferred exemplary embodiment, the invention is not thus limited by the disclosed examples, and other variations can be derived by the person skilled in the art without departing from the extent of protection of the invention.
