Cooling option for an axial compressor

Abstract

The invention comprises an axial compressor (1), comprising a rotatably mounted rotor (2), an inner housing (3) arranged around the rotor (2), a flow channel (4) arranged between the rotor (2) and the inner housing (3), the flow channel (4) being designed to compress a flow medium, an inflow region arranged upstream of the flow channel (4), an outflow region (7) arranged downstream of the flow channel (4), a return channel (22) which is fluidically connected to the outflow region (7), a coolant supply channel (23) which is fluidically connected to the return channel (22), the coolant supply channel (23) being designed for the flow of cooling medium, the return channel (22) and the coolant supply channel (23) opening into a common cooling line (13), the cooling line (13) opening into a region between the rotor (2) and the inner housing (3).

Description

2024PF00217 Subsequent Filing 1 Description TITLE Cooling option for an axial compressor TECHNICAL AREA

[0001] The invention relates to an axial compressor comprising a rotatably mounted rotor, an inner housing arranged around the rotor, a flow channel arranged between the rotor and the inner housing, wherein the flow channel is designed for compressing a flow medium, an inlet area arranged upstream of the flow channel, an outlet area arranged downstream of the flow channel, and a return channel which is fluidically connected to the outlet area. BACKGROUND

[0002] Compressors are turbomachines that require the input of mechanical energy to compress a fluid. This is typically achieved using a drive motor, such as a turbine or an electric motor, to power the compressor's rotor. The fluid, fed into a flow channel, is compressed to a higher pressure and heated in the process.

[0003] However, the high temperatures of the flow medium can locally lead to an overload of rotor, piston and housing materials.

[0004] In particular, air guided between a piston would be heated so intensely by friction that unacceptably high temperatures would develop after the piston space. SUMMARY OF THE INVENTION

[0005] This is where the invention comes in. 2024PF00217 Subsequent Filing 2

[0006] The object of the invention is to provide an axial compressor suitable for high temperatures.

[0007] This problem is solved by an axial compressor comprising a rotatably mounted rotor, an inner housing arranged around the rotor, a flow channel arranged between the rotor and the inner housing, wherein the flow channel is designed for compressing a fluid medium, an inlet area arranged upstream of the flow channel, an outlet area arranged downstream of the flow channel, a return channel which is fluidically connected to the outlet area, a cooling supply channel which is fluidically connected to the return channel, wherein the cooling supply channel is designed for the flow of cooling medium, wherein the return channel and the cooling supply channel open into a common cooling line, wherein the cooling line opens into a region between the rotor and the inner housing.

[0008] Advantageous embodiments are the subject of the dependent claims.

[0009] The dependent claims list further advantages that can be combined in any way to achieve further advantages. DESCRIPTION OF THE INVENTION

[0010] A key aspect of the invention is that cooling is achieved both through cooling from the flow medium in the flow channel and through external cooling via a cooling supply channel. The external cooling, which includes cooling air, serves several purposes. Firstly, the cooling air prevents hot gas from the main flow channel from entering the piston. Additional air friction within the piston would cause the temperature in the cavity between the outer and inner housings to rise to approximately 700°C. 2024PF00217 Subsequent Filing 3

[0011] Secondly, the cooling air serves to limit the temperature in the housing space after the piston to between 400 and 450°C, thus limiting thermal stresses on the inner housing. This results in two control tasks. Depending on the air friction in the piston, a corresponding amount is added via a hot air valve to maintain the temperature between 400 and 450°C. Furthermore, an excess of air must always be ensured to guarantee a defined flow towards the main flow channel. Otherwise, hot gas will flow back, or, in the event of stagnation, rapid heating will occur in the rotor cooling channel due to air friction. With a fixed mixing ratio, the total amount is regulated accordingly to limit the temperature in the rotor cooling channel.

[0012] In a first advantageous embodiment, the rotor has a piston, wherein the cooling line opens into a piston area between the piston and the inner housing.

[0013] In a further advantageous embodiment, an outer housing is arranged around the inner housing, wherein an intermediate space is formed between the inner housing and the outer housing, wherein the intermediate space is fluidically connected to the piston area.

[0014] In a further advantageous embodiment, the axial compressor has a deflection arrangement that connects the flow channel with the outflow area, wherein the deflection arrangement includes a heat protection jacket that is arranged around the rotor, wherein a cooling area is formed between the heat protection jacket and the rotor and the cooling area opens into the flow channel.

[0015] In a further advantageous embodiment, the deflection arrangement includes a pressure boosting device designed to increase the pressure of the flow medium.

[0016] Advantageously, the pressure boosting device includes paddle stages. 2024PF00217 Subsequent Filing 4 In a further advantageous embodiment, the deflection arrangement has a flow-technical connection to a mixing area between the deflection arrangement and the thermal insulation jacket, wherein the mixing area opens into the flow channel.

[0018] Advantageously, the flow-related connection is designed as a bore. Advantageously, the piston area includes a labyrinth seal.

[0020] In a further advantageous development, the flow medium and the cooling medium are air. SHORT DESCRIPTION OF THE SIGNS

[0021] An embodiment of the invention will be explained in more detail below with reference to the following figure.

[0022] The properties, features and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more easily understood in connection with the following description of the exemplary embodiments, which are explained in more detail in conjunction with the drawings.

[0023] Identical components or components with the same function are marked with the same reference numerals.

[0024] Exemplary embodiments of the invention are described below with reference to the drawings. These drawings are not intended to be drawn to scale; rather, where helpful for explanation, they are presented in a schematic and / or slightly distorted form. For further details regarding the teachings directly apparent from the drawings, reference is made to the relevant prior art.

[0025] They show: 2024PF00217 Subsequent Filing 5

[0026] FIG 1 a schematic sectional view of a compressor according to the invention. FIG 2 a further schematic sectional view of the compressor according to the invention.

[0028] FIG 3 a schematic representation of the compressor DESCRIPTION OF THE EXECUTION FORM EN

[0029] Figure 1 shows a schematic sectional view of an axial compressor 1 according to the invention. The axial compressor 1 comprises a rotor 2 rotatably mounted about an axis of rotation (not shown). An inner housing 3 is arranged around the rotor 2. A flow channel 4 is arranged between the rotor 2 and the inner housing 3, formed by compressor guide vanes 5 and compressor impeller blades 6. The compressor guide vanes 5 (only one is shown in Figure 1 for clarity) are connected to the inner housing 3 by suitable fasteners. The compressor impeller blades 6 (only one is shown in Figure 1 for clarity) are connected to the rotor 2 by suitable fasteners. The flow channel 4 is designed for compressing a fluid medium, in this case air. The compressor impeller blades 6 and the compressor guide vanes 5 are used for compression in a known manner.

[0030] Upstream of the flow channel 4 is an inlet area (not shown) through which the fluid flows into the axial compressor 1. Downstream of the flow channel 4 is an outlet area 7, which is designed so that the fluid flows out of the axial compressor 1 in a manner suitable for further use.

[0031] The rotor 2 has a piston 8 which has a labyrinth seal 10 on its piston surface 9. 2024PF00217 Subsequent Filing 6

[0032] During operation, the rotor 2 rotates around the axis of rotation. A fluid flowing through the labyrinth seal 10 from the flow channel 4 would heat up excessively due to friction, causing an intermediate space 11 between the inner housing 3 and an outer housing 12 arranged around the inner housing 3 to overheat.

[0033] To remedy this, a return channel 22 is arranged such that it is fluidically connected to the outflow area 7 (not shown in Figure 1). Furthermore, the return channel 22 is fluidically connected to a cooling supply channel 23 (not shown in Figure 1). The cooling supply channel 23 is designed to carry a cooling medium, in this case, cooling air.

[0034] The return channel 22 and the cooling supply channel 23 open into a common cooling line 13. This cooling line 13 opens into an area between the rotor 2 and the inner housing 3 and leads to a cooling system there.

[0035] Firstly, the cooling medium 14 flows through the labyrinth seal 10 and then into the space 11. Secondly, the cooling medium 14 flows along a rotor surface 15 back to the flow channel 4.

[0036] Furthermore, the axial compressor 1 has a deflection arrangement 16 that connects the flow channel 4 with the outflow area 7. The deflection arrangement 16 includes a thermal protection jacket 17, which is arranged around the rotor 2.

[0037] A cooling zone 18 is formed between the thermal insulation jacket 17 and the rotor 2, with the cooling zone 18 opening into the flow channel 4. In the flow channel 4, the cooling medium mixes with the flow medium. The deflection arrangement 16 includes a pressure boosting device 19 designed to increase the pressure of the flow medium. In a first embodiment, the pressure boosting device 19 is formed from at least one vane stage 20. This pressure boosting device 19 increases the pressure so that the pressure losses from the outflow area 7 via the 2024PF00217 Subsequent Filing 7 subsequent heat exchangers (not shown) and the cooling line 23 with cooling air 25 can be compensated.

[0039] The deflection arrangement 16 has a connecting chamber 21 which is connected to the flow channel 4 via fluid-flow connections (not shown). The medium flowing into the connecting chamber 21 via these fluid-flow connections is then returned to the flow channel 4. Figure 2 shows a section along line AA. As shown in the sectional view according to Figure 2, a cooling medium 14 is conveyed via the cooling line 13 to a suitable location in the axial compressor 1.

[0041] Figure 3 shows a schematic representation of the invention's functionality. To avoid repetition, reference is made to the descriptions of Figures 1 and 2. A return valve 24 is arranged in the return channel 22. The flow rate can be controlled by this return valve 24.

[0042] A cooling supply valve 25 is arranged in the cooling supply channel 23. The flow rate can be regulated with this cooling supply valve 25.

[0043] Depending on how the two valves 24 and 25 are set, the flow rate and temperature in the cooling line 13 can be regulated and thus the optimal temperature for the axial compressor 1 can be set.

[0044] The cooling air supplied into the space can be returned to the inlet area of ​​the axial compressor 1 via a line 26.

[0045] Air is used as the fluid. Air is also used as the cooling medium, although other media are conceivable and can be used. The fluid and cooling media are the same. 2024PF00217 Subsequent Filing 8

[0046] The invention comprises an automation and control device, which is not shown in the figures. The automation and control device includes control units and temperature units and is designed to set the optimal temperature of the cooling medium using the control parameters and variables, which is achieved by controlling valves 24 and 25.

[0047] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples and other variants can be derived by a person skilled in the art without leaving the scope of protection of the invention.

Claims

2024PF00217 Subsequent Filing 9 Claims 1. Axial compressor (1) comprising a rotatably mounted rotor (2), an inner housing (3) arranged around the rotor (2), a flow channel (4) arranged between the rotor (2) and the inner housing (3), wherein the flow channel (4) is designed for compressing a fluid medium, an inlet area arranged upstream of the flow channel (4), an outlet area (7) arranged downstream of the flow channel (4), a return channel (22) fluidically connected to the outlet area (7), a cooling supply channel (23) fluidically connected to the return channel (22), wherein the cooling supply channel (23) is designed for the flow of cooling medium, wherein the return channel (22) and the cooling supply channel (23) open into a common cooling line (13), wherein the cooling line (13) opens into a region between the rotor (2) and the inner housing (3).

2. Axial compressor (1 ) according to claim 1 , wherein the rotor (2) has a piston (8) wherein the cooling line (13) opens into a piston area between piston (8) and the inner housing (3).

3. Axial compressor (1 ) according to claim 2, wherein an outer housing (12) is arranged around the inner housing (3), wherein a space (11 ) is formed between the inner housing (3) and the outer housing (12), 2024PF00217 Subsequent Filing 10 wherein the space (11) is fluidically connected to the piston area.

4. Axial compressor (1 ) according to one of the preceding claims, with a deflection arrangement (16) which connects the flow channel (4) with the outflow region (7), wherein the deflection arrangement (16) comprises a heat protection jacket (17) which is arranged around the rotor (2), wherein a cooling region is formed between the heat protection jacket (17) and the rotor (2) and the cooling region opens into the flow channel (4).

5. Axial compressor (1 ) according to claim 4, wherein the deflection arrangement (16) comprises a pressure boosting device (19) designed to increase the pressure of the flow medium.

6. Axial compressor according to claim 5, wherein the pressure boosting device (19) comprises blade stages (20).

7. Axial compressor (1 ) according to one of claims 4 to 6, wherein the deflection arrangement (16) has a flow-technical connection into a mixing area between the deflection arrangement and the heat protection jacket (17), wherein the mixing area opens into the flow channel (14).

8. Axial compressor (1 ) according to claim 7, wherein the flow connection is designed as a bore.

9. Axial compressor (1 ) according to one of claims 2 to 8, wherein the piston area comprises a labyrinth seal (10).

10. Axial compressor (1 ) according to one of the preceding claims, wherein the flow medium and the cooling medium is air. 2024PF00217 Subsequent Filing 11 11. Axial compressor (1) according to one of the preceding claims, wherein the temperature of the cooling air is between 400 and 500° C.

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