Centrifugal compressor shafting, centrifugal compressors and air conditioners

Abstract

The present invention relates to a centrifugal compressor shaft system, a centrifugal compressor and an air conditioner. By matching and designing various geometric parameters of the shaft system, the shaft system can operate stably even when used at high speed and high load, thereby improving the stability and reliability of use. Specifically, it relates to the cantilever length ratio L2 / L1 and L3 / L1 of the shaft system, the support installation width ratio B1 / L2 and B2 / L3, the width-to-diameter ratio B1 / D1 and B2 / D2 of the support, the center-of-gravity offset rate abs(L4-L5) / (L1 / 2) of the shaft system, and the impeller length-to-diameter ratio L6 / D3 and L7 / D4.

Description

Technical Field

[0001] The invention relates to the technical field of compressors, in particular to a centrifugal compressor shaft system, a centrifugal compressor and an air conditioner. Background Art

[0002] In centrifugal compressors, the impeller rotates at high speed to do work for the gas. Under the action of centrifugal force, the gas is thrown out with high pressure and speed. The rotation of the impeller is driven by the rotating shaft of the centrifugal compressor. With the development of science and technology, according to the actual needs of consumers, the performance requirements of compressor speed and load in various use environments are constantly increasing. However, the increase in speed and load will cause the shaft system to get closer and closer to the critical speed when running, which will eventually reduce the stability of the shaft system. Summary of the invention

[0003] Aiming at the problem of shaft system running stability under high-speed operation and high-load conditions, the present invention proposes a centrifugal compressor shaft system, a centrifugal compressor and an air conditioner to improve the stability during operation.

[0004] A centrifugal compressor shaft system, comprising:

[0005] A rotating shaft, wherein the rotating shaft is provided with a first impeller assembly, a first support member, a second support member, and a second impeller assembly which are sequentially arranged along the axial direction of the rotating shaft, the midpoint of the rotating shaft and the acting part of the first support member is a first supporting point, the width of the acting part is a first supporting width B1, and the shaft diameter of the acting part is a first supporting shaft diameter D1, the midpoint of the rotating shaft and the acting part of the second support member is a second supporting point, the width of the acting part is a second supporting width B2, and the shaft diameter of the acting part is a second supporting shaft diameter D2, and the spacing between the first supporting point and the second supporting point is a first spacing L1;

[0006] The distance between the end surface of the first impeller assembly away from the first support member and the first support point is a first cantilever length L2, the distance between the end surface of the second impeller assembly away from the second support member and the second support point is a second cantilever length L3, L2 / L1 is 0.26-0.77, L3 / L1 is 0.27-0.78;

[0007] B1 / L2 is 0.18-0.59, B2 / L3 is 0.17-0.58;

[0008] B1 / D1 is 0.50-1.3, B2 / D2 is 0.48-1.3;

[0009] The distance between the first support point and the center of gravity of the rotating shaft is a second distance L4, the distance between the second support point and the center of gravity of the rotating shaft is a third distance L5, and abs(L4-L5) / (L1 / 2) is 0-0.1;

[0010] The distance between the blade root of the first impeller assembly and the reference line on the hub outlet side of the first impeller assembly is a first installation length L6, the distance between the blade root of the second impeller assembly and the reference line on the hub outlet side of the second impeller assembly is a second installation length L7, the ratio of the first installation length L6 to the outer diameter D3 of the first impeller assembly is 0.155 to 0.235, and the ratio of the second installation length L7 to the outer diameter D4 of the second impeller assembly is 0.135 to 0.225.

[0011] The above scheme provides a centrifugal compressor shaft system, which can be designed to match various geometric parameters of the shaft system so that the shaft system can operate stably even when used at high speed and high load, thereby improving the stability and reliability of use. Specifically, it involves the cantilever length ratio L2 / L1 and L3 / L1 of the shaft system, the support installation width ratio B1 / L2 and B2 / L3, the support width ratio B1 / D1 and B2 / D2, the shaft system center of gravity offset ratio abs(L4-L5) / (L1 / 2), and the impeller length-diameter ratio L6 / D3 and L7 / D4.

[0012] In one embodiment, the first impeller assembly includes a first impeller, the second impeller assembly includes a second impeller, the distance between the end surface of the first impeller away from the first support member and the first support point is the first cantilever length L2, the distance between the end surface of the second impeller away from the second support member and the second support point is the second cantilever length L3, the distance between the blade root of the first impeller and the reference line on the hub outlet side of the first impeller is the first installation length L6, the distance between the blade root of the second impeller and the reference line on the hub outlet side of the second impeller is the second installation length L7, the outer diameter of the first impeller is D3, and the outer diameter of the second impeller is D4.

[0013] In one embodiment, the first impeller and the second impeller are both used for introducing positive pressure working medium, the first support member and the second support member both include oil-lubricated bearings, the oil-lubricated bearings are sleeved on the rotating shaft, L2 / L1 is 0.29-0.33, L3 / L1 is 0.30-0.34, B1 / L2 is 0.32-0.37, B2 / L3 is 0.31-0.36, B1 / D1 is 0.9-1.2, B2 / D2 is 0.8-1.1, abs(L4-L5) / (L1 / 2) is 0-0.1, L6 / D3 is 0.205-0.225, and L7 / D4 is 0.195-0.215.

[0014] In one embodiment, the first impeller and the second impeller are both used to introduce positive pressure working medium, the first support member and the second support member both include magnetic bearings, and the magnetic bearings are sleeved on the rotating shaft, L2 / L1 is 0.26-0.30, L3 / L1 is 0.27-0.31, B1 / L2 is 0.36-0.41, B2 / L3 is 0.35-0.40, B1 / D1 is 0.50-0.56, B2 / D2 is 0.48-0.54, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.195-0.225, and L7 / D4 is 0.175-0.205.

[0015] In one embodiment, the first impeller assembly and the second impeller assembly are both used to introduce positive pressure working medium, the first support member and the second support member both include gas bearings, the gas bearings are sleeved on the rotating shaft, L2 / L1 is 0.28-0.32, L3 / L1 is 0.29-0.33, B1 / L2 is 0.51-0.56, B2 / L3 is 0.50-0.55, B1 / D1 is 0.8-1.1, B2 / D2 is 0.7-1.1, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.155-0.195, and L7 / D4 is 0.135-0.175.

[0016] In one embodiment, the first impeller and the second impeller are both used for introducing negative pressure working medium, the first support member and the second support member both include oil-lubricated bearings, the oil-lubricated bearings are sleeved on the rotating shaft, L2 / L1 is 0.41-0.47, L3 / L1 is 0.42-0.48, B1 / L2 is 0.27-0.31, B2 / L3 is 0.26-0.30, B1 / D1 is 0.9-1.2, B2 / D2 is 0.9-1.2, abs(L4-L5) / (L1 / 2) is 0-0.10, L6 / D3 is 0.215-0.235, and L7 / D4 is 0.205-0.225.

[0017] In one embodiment, the first impeller and the second impeller are both used for introducing negative pressure working medium, the first support member and the second support member both include magnetic bearings, and the magnetic bearings are sleeved on the rotating shaft, L2 / L1 is 0.37-0.44, L3 / L1 is 0.38-0.45, B1 / L2 is 0.39-0.46, B2 / L3 is 0.38-0.45, B1 / D1 is 0.56-0.62, B2 / D2 is 0.55-0.61, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.205-0.225, and L7 / D4 is 0.195-0.215.

[0018] In one embodiment, the first impeller and the second impeller are both used for introducing negative pressure working medium, the first support member and the second support member both include gas bearings, and the gas bearings are sleeved on the rotating shaft, L2 / L1 is 0.38-0.45, L3 / L1 is 0.39-0.46, B1 / L2 is 0.53-0.59, B2 / L3 is 0.52-0.58, B1 / D1 is 0.9-1.3, B2 / D2 is 0.8-1.2, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.205-0.225, and L7 / D4 is 0.195-0.215.

[0019] In one embodiment, the first impeller assembly includes a first impeller and a third impeller, the second impeller assembly includes a second impeller and a fourth impeller, the third impeller is located between the first impeller and the first support member, the fourth impeller is located between the second impeller and the second support member, the distance between the end surface of the first impeller away from the first support member and the first support point is the first cantilever length L2, the distance between the end surface of the second impeller away from the second support member and the second support point is the second cantilever length L3, the distance between the blade root of the third impeller and the reference line on the hub outlet side of the third impeller is the first installation length L6, the distance between the blade root of the fourth impeller and the reference line on the hub outlet side of the fourth impeller is the second installation length L7, the outer diameter of the third impeller is D3, and the outer diameter of the fourth impeller is D4.

[0020] In one embodiment, the first impeller assembly and the second impeller assembly are both used for introducing negative pressure working medium, the first support member and the second support member both include oil-lubricated bearings, the oil-lubricated bearings are sleeved on the rotating shaft, L2 / L1 is 0.71-0.77, L3 / L1 is 0.72-0.78, B1 / L2 is 0.18-0.22, B2 / L3 is 0.17-0.22, B1 / D1 is 0.9-1.2, B2 / D2 is 0.9-1.2, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.205-0.225, and L7 / D4 is 0.195-0.215.

[0021] In one embodiment, the first impeller assembly and the second impeller assembly are both used to introduce negative pressure working medium, the first support member and the second support member both include magnetic bearings, and the magnetic bearings are sleeved on the rotating shaft, L2 / L1 is 0.57-0.63, L3 / L1 is 0.59-0.65, B1 / L2 is 0.26-0.31, B2 / L3 is 0.25-0.30, B1 / D1 is 0.59-0.66, B2 / D2 is 0.59-0.66, abs(L4-L5) / (L1 / 2) is 0-0.08, L6 / D3 is 0.195-0.215, and L7 / D4 is 0.185-0.205.

[0022] In one embodiment, the first impeller assembly and the second impeller assembly are both used for introducing negative pressure working medium, the first support member and the second support member both include gas bearings, the gas bearings are sleeved on the rotating shaft, L2 / L1 is 0.66-0.72, L3 / L1 is 0.67-0.73, B1 / L2 is 0.36-0.41, B2 / L3 is 0.35-0.40, B1 / D1 is 0.9-1.3, B2 / D2 is 0.9-1.3, abs(L4-L5) / (L1 / 2) is 0-0.08, L6 / D3 is 0.195-0.215, and L7 / D4 is 0.185-0.205.

[0023] In one embodiment, the pneumatic flow passage capacity of the first impeller assembly is greater than the pneumatic flow passage capacity of the second impeller assembly.

[0024] In one embodiment, the ratio of the pneumatic flow channel capacity of the first impeller assembly to the pneumatic flow channel capacity of the second impeller assembly is 1.0 to 1.1;

[0025] The specific speed of the first impeller assembly is 105-115, and the specific speed of the second impeller assembly is 70-85.

[0026] A centrifugal compressor comprises the above-mentioned centrifugal compressor shaft system.

[0027] The above scheme provides a centrifugal compressor. By adopting the shaft system described in any of the above embodiments, the centrifugal compressor can operate stably even under high speed and high load conditions, thereby improving the stability and reliability of use.

[0028] An air conditioner comprises the centrifugal compressor mentioned above.

[0029] The above scheme provides an air conditioner, which, by adopting the centrifugal compressor described in any of the above embodiments, can maintain stability even when the air conditioner is running at high speed, thereby improving the stability and reliability of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 is a cross-sectional view of the centrifugal compressor described in this embodiment;

[0033] Figure 2 for Figure 1 The schematic diagram of the structure of the shaft system in the centrifugal compressor shown;

[0034] Figure 3 is a cross-sectional view of a centrifugal compressor according to another embodiment;

[0035] Figure 4 for Figure 3 Schematic diagram of the structure of the shaft system in the centrifugal compressor shown.

[0036] Description of reference numerals:

[0037] 10. Shaft system; 11. Rotating shaft; 12. First impeller; 13. Second impeller; 14. Third impeller; 15. Fourth impeller; 16. First support member; 17. Second support member; 20. Centrifugal compressor. DETAILED DESCRIPTION

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0039] like Figure 1 and Figure 2 As shown, in one embodiment, a shaft system 10 of a centrifugal compressor 20 is provided, comprising:

[0040] A rotating shaft 11, wherein the rotating shaft 11 is provided with a first impeller assembly, a first support member 16, a second support member 17, and a second impeller assembly arranged in sequence along the axial direction of the rotating shaft 11. The midpoint of the portion of the rotating shaft 11 that interacts with the first support member 16 is the first support point, the width of this portion is the first support width B1, and the shaft diameter of this portion is the first support shaft diameter D1. The midpoint of the portion of the rotating shaft 11 that interacts with the second support member 17 is the second support point, the width of this portion is the second support width B2, and the shaft diameter of this portion is the second support shaft diameter D2. The distance between the first support point and the second support point is the first distance L1;

[0041] The distance between the end surface of the first impeller assembly away from the first support member 16 and the first support point is the first cantilever length L2, the distance between the end surface of the second impeller assembly away from the second support member 17 and the second support point is the second cantilever length L3, L2 / L1 is 0.26-0.77, L3 / L1 is 0.27-0.78;

[0042] B1 / L2 is 0.18-0.59, B2 / L3 is 0.17-0.58;

[0043] B1 / D1 is 0.50-1.3, B2 / D2 is 0.48-1.3;

[0044] The distance between the first support point and the center of gravity of the rotating shaft 11 is a second distance L4, the distance between the second support point and the center of gravity of the rotating shaft 11 is a third distance L5, and abs(L4-L5) / (L1 / 2) is 0-0.1;

[0045] The distance between the blade root of the first impeller assembly and the reference line on the hub outlet side of the first impeller assembly is a first installation length L6, the distance between the blade root of the second impeller assembly and the reference line on the hub outlet side of the second impeller assembly is a second installation length L7, the ratio of the first installation length L6 to the outer diameter D3 of the first impeller assembly is 0.155 to 0.235, and the ratio of the second installation length L7 to the outer diameter D4 of the second impeller assembly is 0.135 to 0.225.

[0046] The above scheme provides a shaft system 10 of a centrifugal compressor 20, which can be stably operated even under high speed and high load conditions by matching and designing various geometric parameters of the shaft system 10, thereby improving the stability and reliability of use. Specifically, it involves the cantilever length ratios L2 / L1 and L3 / L1 of the shaft system 10, the support installation width ratios B1 / L2 and B2 / L3, the width-to-diameter ratios B1 / D1 and B2 / D2 of the support, the center-of-gravity offset ratio abs(L4-L5) / (L1 / 2) of the shaft system 10, and the impeller length-to-diameter ratios L6 / D3 and L7 / D4.

[0047] Furthermore, when the shaft system 10 of the centrifugal compressor 20 is applied to different working fluid environments, different working fluids have certain differences in molecular weight, density, specific volume and other characteristics, and different requirements are placed on the support strength of the shaft system 10. For example, compared with the case where the shaft system 10 is used for positive pressure working fluids such as R134a working fluid or R1234ze working fluid, when the shaft system 10 is used for negative pressure working fluids such as R245fa working fluid or R1233zd(E) working fluid, since the specific volume of R1233zd(E) is larger than that of R134a, the shaft system 10 is larger at both ends, and L2 / L1 and L3 / L1 are larger.

[0048] Furthermore, the support form of the rotating shaft 11 also affects the load capacity and stability of the rotating shaft 11. For example, the shaft system 10 based on lubricating oil bearings can withstand a larger load, while the shaft system 10 based on magnetic bearings and the shaft system 10 based on gas bearings have relatively smaller support stiffness.

[0049] Furthermore, in actual use, the shaft system 10 can be a double-cantilever double-impeller shaft system 10, that is, an impeller is respectively arranged at both ends of the rotating shaft 11, or the shaft system 10 can also be a double-cantilever four-impeller shaft system 10, and two impellers are respectively arranged at both ends of the rotating shaft 11.

[0050] Specifically, Figure 1 and Figure 2 As shown, in one embodiment, the first impeller assembly includes a first impeller 12 , and the second impeller assembly includes a second impeller 13 .

[0051] At this time, if Figure 2 As shown, the distance between the end surface of the first impeller 12 away from the first support member 16 and the first support point is the first cantilever length L2, the distance between the end surface of the second impeller 13 away from the second support member 17 and the second support point is the second cantilever length L3, the distance between the blade root of the first impeller 12 and the reference line on the hub outlet side of the first impeller 12 is the first installation length L6, the distance between the blade root of the second impeller 13 and the reference line on the hub outlet side of the second impeller 13 is the second installation length L7, the outer diameter of the first impeller 12 is D3, and the outer diameter of the second impeller 13 is D4.

[0052] More specifically, in one embodiment, Figure 1 and Figure 2 As shown, the first impeller 12 and the second impeller 13 are both used to pass positive pressure working fluid. For example, the first impeller 12 and the second impeller 13 can be used to pass R134a working fluid or R1234ze working fluid. The first support member 16 and the second support member 17 both include oil-lubricated bearings, and the oil-lubricated bearings are sleeved on the rotating shaft 11. Based on the fact that the first impeller 12 and the second impeller 13 pass positive pressure working fluid, and the oil-lubricated bearings can withstand a large support strength, under the same load, the cantilever length can be designed to be longer, and the diameter and width of the bearing can be designed to be relatively small. For example, L2 / L1 is 0.29~0.33, L3 / L1 is 0.30~0.34, B1 / L2 is 0.32~0.37, B2 / L3 is 0.31~0.36, B1 / D1 is 0.9~1.2, B2 / D2 is 0.8~1.1, abs(L4-L5) / (L1 / 2) is 0~0.1, L6 / D3 is 0.205~0.225, and L7 / D4 is 0.195~0.215.

[0053] More specifically, in another embodiment, Figure 1 and Figure 2As shown, the first impeller 12 and the second impeller 13 are both used to pass positive pressure working fluid. For example, the first impeller 12 and the second impeller 13 can be used to pass R134a working fluid or R1234ze working fluid. The first support member 16 and the second support member 17 both include magnetic bearings, and the magnetic bearings are sleeved on the rotating shaft 11. Compared with the previous scheme, the working fluid used in this scheme is the same, but the bearings used are different. Compared with oil-lubricated bearings, the support stiffness of magnetic bearings is lower. Based on this, under the same load, the cantilever length of the shaft system 10 is relatively short, and the diameter and width of the bearings are relatively long. For example, L2 / L1 is 0.26~0.30, L3 / L1 is 0.27~0.31, B1 / L2 is 0.36~0.41, B2 / L3 is 0.35~0.40, B1 / D1 is 0.50~0.56, B2 / D2 is 0.48~0.54, abs(L4-L5) / (L1 / 2) is 0~0.09, L6 / D3 is 0.195~0.225, and L7 / D4 is 0.175~0.205.

[0054] Similarly, in another embodiment, if Figure 1 and Figure 2 As shown, both the first impeller 12 and the second impeller 13 are used to introduce positive pressure working fluid. For example, the first impeller 12 and the second impeller 13 can be used to introduce R134a working fluid or R1234ze working fluid. Both the first support member 16 and the second support member 17 include gas bearings, and the gas bearings are sleeved on the rotating shaft 11. At this time, L2 / L1 is 0.28-0.32, L3 / L1 is 0.29-0.33, B1 / L2 is 0.51-0.56, B2 / L3 is 0.50-0.55, B1 / D1 is 0.8-1.1, B2 / D2 is 0.7-1.1, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.155-0.195, and L7 / D4 is 0.135-0.175.

[0055] Furthermore, compared with positive pressure fluids such as R134a or R1234ze, negative pressure fluids such as R245fa or R1233zd(E) have larger specific volumes. Under the same capacity, the impellers at both ends of the shaft system 10 have larger dimensions and heavier mass.

[0056] Specifically, in one embodiment, the first impeller 12 and the second impeller 13 are both used to pass negative pressure working fluid. For example, the first impeller 12 and the second impeller 13 can be used to pass R245fa working fluid or R1233zd (E) working fluid. The first support member 16 and the second support member 17 both include oil-lubricated bearings, and the oil-lubricated bearings are sleeved on the rotating shaft 11. At this time, L2 / L1 is 0.41~0.47, L3 / L1 is 0.42~0.48, B1 / L2 is 0.27~0.31, B2 / L3 is 0.26~0.30, B1 / D1 is 0.9~1.2, B2 / D2 is 0.9~1.2, abs(L4-L5) / (L1 / 2) is 0~0.10, L6 / D3 is 0.215~0.235, and L7 / D4 is 0.205~0.225.

[0057] More specifically, in another embodiment, the first impeller 12 and the second impeller 13 are both used to introduce negative pressure working fluid. For example, the first impeller 12 and the second impeller 13 can be used to introduce R245fa working fluid or R1233zd(E) working fluid. The first support member 16 and the second support member 17 both include magnetic suspension bearings, and the magnetic suspension bearings are sleeved on the rotating shaft 11. At this time, L2 / L1 is 0.37~0.44, L3 / L1 is 0.38~0.45, B1 / L2 is 0.39~0.46, B2 / L3 is 0.38~0.45, B1 / D1 is 0.56~0.62, B2 / D2 is 0.55~0.61, abs(L4-L5) / (L1 / 2) is 0~0.09, L6 / D3 is 0.205~0.225, and L7 / D4 is 0.195~0.215.

[0058] Further, in another embodiment, the first impeller 12 and the second impeller 13 are both used to introduce negative pressure working fluid. For example, the first impeller 12 and the second impeller 13 can be used to introduce R245fa working fluid or R1233zd(E) working fluid. The first support member 16 and the second support member 17 both include gas bearings, and the gas bearings are sleeved on the rotating shaft 11. At this time, L2 / L1 is 0.38~0.45, L3 / L1 is 0.39~0.46, B1 / L2 is 0.53~0.59, B2 / L3 is 0.52~0.58, B1 / D1 is 0.9~1.3, B2 / D2 is 0.8~1.2, abs(L4-L5) / (L1 / 2) is 0~0.09, L6 / D3 is 0.205~0.225, and L7 / D4 is 0.195~0.215.

[0059] Further, in one embodiment, for a large capacity compressor, Figure 3 and Figure 4 As shown, the shaft system 10 adopts a double cantilever four-impeller shaft system 10. The first impeller assembly and the second impeller assembly on both sides of the shaft system 10 can be compressed independently, but they share a common motor drive. The first impeller assembly includes a first impeller 12 and a third impeller 14, and the second impeller assembly includes a second impeller 13 and a fourth impeller 15. The third impeller 14 is located between the first impeller 12 and the first support 16, and the fourth impeller 15 is located between the second impeller 13 and the second support 17. At this time, the distance between the end surface of the first impeller 12 away from the first support member 16 and the first support point is the first cantilever length L2, the distance between the end surface of the second impeller 13 away from the second support member 17 and the second support point is the second cantilever length L3, the distance between the blade root of the third impeller 14 and the reference line on the hub outlet side of the third impeller 14 is the first installation length L6, the distance between the blade root of the fourth impeller 15 and the reference line on the hub outlet side of the fourth impeller 15 is the second installation length L7, the outer diameter of the third impeller 14 is D3, and the outer diameter of the fourth impeller 15 is D4.

[0060] Specifically, in one embodiment, the first impeller assembly and the second impeller assembly are both used to introduce negative pressure working fluid. For example, the first impeller 12 and the second impeller 13 can be used to introduce R245fa working fluid or R1233zd (E) working fluid. The first support member 16 and the second support member 17 both include oil-lubricated bearings, and the oil-lubricated bearings are sleeved on the rotating shaft 11. L2 / L1 is 0.71~0.77, L3 / L1 is 0.72~0.78, B1 / L2 is 0.18~0.22, B2 / L3 is 0.17~0.22, B1 / D1 is 0.9~1.2, B2 / D2 is 0.9~1.2, abs(L4-L5) / (L1 / 2) is 0~0.09, L6 / D3 is 0.205~0.225, L7 / D4 is 0.195~0.215.

[0061] Further, in another embodiment, the first impeller assembly and the second impeller assembly are both used to introduce negative pressure working fluid. For example, the first impeller 12 and the second impeller 13 can be used to introduce R245fa working fluid or R1233zd(E) working fluid. The first support member 16 and the second support member 17 both include magnetic suspension bearings, and the magnetic suspension bearings are sleeved on the rotating shaft 11. L2 / L1 is 0.57~0.63, L3 / L1 is 0.59~0.65, B1 / L2 is 0.26~0.31, B2 / L3 is 0.25~0.30, B1 / D1 is 0.59~0.66, B2 / D2 is 0.59~0.66, abs(L4-L5) / (L1 / 2) is 0~0.08, L6 / D3 is 0.195~0.215, L7 / D4 is 0.185~0.205.

[0062] Further, in yet another embodiment, the first impeller assembly and the second impeller assembly are both used to introduce negative pressure working fluid. For example, the first impeller 12 and the second impeller 13 can be used to introduce R245fa working fluid or R1233zd(E) working fluid. The first support member 16 and the second support member 17 both include gas bearings, and the gas bearings are sleeved on the rotating shaft 11. L2 / L1 is 0.66~0.72, L3 / L1 is 0.67~0.73, B1 / L2 is 0.36~0.41, B2 / L3 is 0.35~0.40, B1 / D1 is 0.9~1.3, B2 / D2 is 0.9~1.3, abs(L4-L5) / (L1 / 2) is 0~0.08, L6 / D3 is 0.195~0.215, L7 / D4 is 0.185~0.205.

[0063] Furthermore, when the shaft system 10 is a double-cantilever four-impeller shaft system 10, in order to improve the applicable operating range of the shaft system 10, the pneumatic flow channel capacity on both sides of the shaft system 10 can be set to be unequal. Specifically, in one embodiment, the pneumatic flow channel capacity of the first impeller assembly is greater than the pneumatic flow channel capacity of the second impeller assembly.

[0064] Preferably, considering that the weight difference on both sides of the shaft system 10 is not easy to be too large, based on this in one embodiment, the ratio of the pneumatic flow channel capacity of the first impeller assembly to the pneumatic flow channel capacity of the second impeller assembly is 1.0 to 1.1.

[0065] The specific speed of the first impeller assembly is 105 to 115, and the specific speed of the second impeller assembly is 70 to 85. It should be noted that the specific speed data here are in American units.

[0066] The pneumatic flow passage on the side where the first impeller assembly is located has a larger capacity, a higher speed and a smaller outer diameter, so that the length and weight of the large-capacity side shaft system 10 can be appropriately reduced to avoid instability. The pneumatic flow passage on the side where the second impeller assembly is located has a smaller capacity, a lower impeller speed and a larger size.

[0067] Furthermore, in one embodiment, the exhaust port of the first impeller assembly is connected to the intake port of the second impeller assembly, thereby realizing four-stage series compression, further improving the pressure ratio, and expanding the application range of the shaft system 10.

[0068] Furthermore, in another embodiment, a centrifugal compressor 20 is provided, comprising the shaft system 10 of any of the above-mentioned centrifugal compressors 20. By adopting the shaft system 10 described in any of the above-mentioned embodiments, the centrifugal compressor 20 can operate stably even under high speed and high load conditions, thereby improving the stability and reliability of use.

[0069] Furthermore, in yet another embodiment, an air conditioner is provided, comprising the centrifugal compressor 20 described above.

[0070] The above scheme provides an air conditioner, which adopts the centrifugal compressor 20 described in any of the above embodiments, so that the air conditioner can remain stable even when running at high speed, thereby improving the stability and reliability of use.

[0071] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0072] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0073] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0075] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0076] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A centrifugal compressor shaft system, characterized in that: include: A rotating shaft, wherein the rotating shaft is provided with a first impeller assembly, a first support member, a second support member, and a second impeller assembly which are sequentially arranged along the axial direction of the rotating shaft, the midpoint of the rotating shaft and the acting part of the first support member is a first supporting point, the width of the acting part is a first supporting width B1, and the shaft diameter of the acting part is a first supporting shaft diameter D1, the midpoint of the rotating shaft and the acting part of the second support member is a second supporting point, the width of the acting part is a second supporting width B2, and the shaft diameter of the acting part is a second supporting shaft diameter D2, and the spacing between the first supporting point and the second supporting point is a first spacing L1; The distance between the end surface of the first impeller assembly away from the first support member and the first support point is a first cantilever length L2, the distance between the end surface of the second impeller assembly away from the second support member and the second support point is a second cantilever length L3, L2 / L1 is 0.26-0.77, L3 / L1 is 0.27-0.78; B1 / L2 is 0.18-0.59, B2 / L3 is 0.17-0.58; B1 / D1 is 0.50-1.3, B2 / D2 is 0.48-1.3; The distance between the first support point and the center of gravity of the rotating shaft is a second distance L4, the distance between the second support point and the center of gravity of the rotating shaft is a third distance L5, and abs(L4-L5) / (L1 / 2) is 0-0.1; The distance between the blade root of the first impeller assembly and the reference line on the hub outlet side of the first impeller assembly is a first installation length L6, the distance between the blade root of the second impeller assembly and the reference line on the hub outlet side of the second impeller assembly is a second installation length L7, the ratio of the first installation length L6 to the outer diameter D3 of the first impeller assembly is 0.155 to 0.235, and the ratio of the second installation length L7 to the outer diameter D4 of the second impeller assembly is 0.135 to 0.

225.

2. The centrifugal compressor shaft system according to claim 1, characterized in that: The first impeller assembly includes a first impeller, and the second impeller assembly includes a second impeller. The distance between the end surface of the first impeller away from the first support member and the first support point is the first cantilever length L2, the distance between the end surface of the second impeller away from the second support member and the second support point is the second cantilever length L3, the distance between the blade root of the first impeller and the reference line on the hub outlet side of the first impeller is the first installation length L6, the distance between the blade root of the second impeller and the reference line on the hub outlet side of the second impeller is the second installation length L7, the outer diameter of the first impeller is D3, and the outer diameter of the second impeller is D4.

3. The centrifugal compressor shaft system according to claim 2, characterized in that: The first impeller and the second impeller are both used for introducing positive pressure working medium, the first support member and the second support member both include oil-lubricated bearings, the oil-lubricated bearings are sleeved on the rotating shaft, L2 / L1 is 0.29-0.33, L3 / L1 is 0.30-0.34, B1 / L2 is 0.32-0.37, B2 / L3 is 0.31-0.36, B1 / D1 is 0.9-1.2, B2 / D2 is 0.8-1.1, abs(L4-L5) / (L1 / 2) is 0-0.1, L6 / D3 is 0.205-0.225, and L7 / D4 is 0.195-0.

215.

4. The centrifugal compressor shaft system according to claim 2, characterized in that: The first impeller and the second impeller are both used for introducing positive pressure working medium, the first support member and the second support member both include magnetic suspension bearings, and the magnetic suspension bearings are sleeved on the rotating shaft, L2 / L1 is 0.26-0.30, L3 / L1 is 0.27-0.31, B1 / L2 is 0.36-0.41, B2 / L3 is 0.35-0.40, B1 / D1 is 0.50-0.56, B2 / D2 is 0.48-0.54, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.195-0.225, and L7 / D4 is 0.175-0.

205.

5. The centrifugal compressor shaft system according to claim 2, characterized in that: The first impeller assembly and the second impeller assembly are both used for introducing positive pressure working medium, the first support member and the second support member both include gas bearings, the gas bearings are sleeved on the rotating shaft, L2 / L1 is 0.28-0.32, L3 / L1 is 0.29-0.33, B1 / L2 is 0.51-0.56, B2 / L3 is 0.50-0.55, B1 / D1 is 0.8-1.1, B2 / D2 is 0.7-1.1, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.155-0.195, and L7 / D4 is 0.135-0.

175.

6. The centrifugal compressor shaft system according to claim 2, characterized in that: The first impeller and the second impeller are both used for introducing negative pressure working medium, the first support member and the second support member both include oil-lubricated bearings, the oil-lubricated bearings are sleeved on the rotating shaft, L2 / L1 is 0.41-0.47, L3 / L1 is 0.42-0.48, B1 / L2 is 0.27-0.31, B2 / L3 is 0.26-0.30, B1 / D1 is 0.9-1.2, B2 / D2 is 0.9-1.2, abs(L4-L5) / (L1 / 2) is 0-0.10, L6 / D3 is 0.215-0.235, and L7 / D4 is 0.205-0.

225.

7. The centrifugal compressor shaft system according to claim 2, characterized in that: The first impeller and the second impeller are both used for introducing negative pressure working medium, the first support member and the second support member both include magnetic suspension bearings, and the magnetic suspension bearings are sleeved on the rotating shaft, L2 / L1 is 0.37-0.44, L3 / L1 is 0.38-0.45, B1 / L2 is 0.39-0.46, B2 / L3 is 0.38-0.45, B1 / D1 is 0.56-0.62, B2 / D2 is 0.55-0.61, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.205-0.225, and L7 / D4 is 0.195-0.

215.

8. The centrifugal compressor shaft system according to claim 2, characterized in that: The first impeller and the second impeller are both used for introducing negative pressure working medium, the first support member and the second support member both include gas bearings, and the gas bearings are sleeved on the rotating shaft, L2 / L1 is 0.38-0.45, L3 / L1 is 0.39-0.46, B1 / L2 is 0.53-0.59, B2 / L3 is 0.52-0.58, B1 / D1 is 0.9-1.3, B2 / D2 is 0.8-1.2, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.205-0.225, and L7 / D4 is 0.195-0.

215.

9. The centrifugal compressor shaft system according to claim 1, characterized in that: The first impeller assembly includes a first impeller and a third impeller, the second impeller assembly includes a second impeller and a fourth impeller, the third impeller is located between the first impeller and the first support member, the fourth impeller is located between the second impeller and the second support member, the distance between the end surface of the first impeller away from the first support member and the first support point is the first cantilever length L2, the distance between the end surface of the second impeller away from the second support member and the second support point is the second cantilever length L3, the distance between the blade root of the third impeller and the reference line on the hub outlet side of the third impeller is the first installation length L6, the distance between the blade root of the fourth impeller and the reference line on the hub outlet side of the fourth impeller is the second installation length L7, the outer diameter of the third impeller is D3, and the outer diameter of the fourth impeller is D4.

10. The centrifugal compressor shaft system according to claim 9, characterized in that: The first impeller assembly and the second impeller assembly are both used for introducing negative pressure working medium, the first support member and the second support member both include oil-lubricated bearings, the oil-lubricated bearings are sleeved on the rotating shaft, L2 / L1 is 0.71-0.77, L3 / L1 is 0.72-0.78, B1 / L2 is 0.18-0.22, B2 / L3 is 0.17-0.22, B1 / D1 is 0.9-1.2, B2 / D2 is 0.9-1.2, abs(L4-L5) / (L1 / 2) is 0-0.09, L6 / D3 is 0.205-0.225, and L7 / D4 is 0.195-0.

215.

11. The centrifugal compressor shaft system according to claim 9, characterized in that: The first impeller assembly and the second impeller assembly are both used for introducing negative pressure working medium, the first support member and the second support member both include magnetic suspension bearings, and the magnetic suspension bearings are sleeved on the rotating shaft, L2 / L1 is 0.57-0.63, L3 / L1 is 0.59-0.65, B1 / L2 is 0.26-0.31, B2 / L3 is 0.25-0.30, B1 / D1 is 0.59-0.66, B2 / D2 is 0.59-0.66, abs(L4-L5) / (L1 / 2) is 0-0.08, L6 / D3 is 0.195-0.215, and L7 / D4 is 0.185-0.

205.

12. The centrifugal compressor shaft system according to claim 9, characterized in that: The first impeller assembly and the second impeller assembly are both used for introducing negative pressure working medium, the first support member and the second support member both include gas bearings, the gas bearings are sleeved on the rotating shaft, L2 / L1 is 0.66-0.72, L3 / L1 is 0.67-0.73, B1 / L2 is 0.36-0.41, B2 / L3 is 0.35-0.40, B1 / D1 is 0.9-1.3, B2 / D2 is 0.9-1.3, abs(L4-L5) / (L1 / 2) is 0-0.08, L6 / D3 is 0.195-0.215, and L7 / D4 is 0.185-0.

205.

13. The centrifugal compressor shaft system according to any one of claims 9 to 12, characterized in that: The pneumatic flow passage capacity of the first impeller assembly is greater than the pneumatic flow passage capacity of the second impeller assembly.

14. The centrifugal compressor shaft system according to claim 13, characterized in that: The ratio of the pneumatic flow passage capacity of the first impeller assembly to the pneumatic flow passage capacity of the second impeller assembly is 1.0 to 1.1; The specific speed of the first impeller assembly is 105-115, and the specific speed of the second impeller assembly is 70-85.

15. A centrifugal compressor, characterized in that: A centrifugal compressor shafting comprising any one of claims 1 to 14.

16. An air conditioner, characterized in that: Comprising the centrifugal compressor as claimed in claim 15.

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