Self-circulation casing of centrifugal compressor and centrifugal compressor

Abstract

The invention provides a self-circulation casing of a centrifugal compressor and the centrifugal compressor, and relates to the technical field of centrifugal compressors, a self-circulation casing channel group of the self-circulation casing of the centrifugal compressor comprises N self-circulation casing channels, and at least one design parameter of each self-circulation casing channel is different, the design parameters at least comprise the positions of the air entraining ports, different positions of the air entraining ports are configured for all the self-circulation casing channels, so that the different self-circulation casing channels are matched with different compressor working conditions, and the started self-circulation casing channels are switched through the rotatable gasket, so that the self-circulation casing channels are switched to be matched with different compressor working conditions. Therefore, the compressor can start different self-circulation casing channels under different working conditions, so that the compressor applying the self-circulation casing channel group can keep higher efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifugal compressors, in particular to a centrifugal compressor self-circulation casing and a centrifugal compressor. Background Art

[0002] Currently, control and stabilization technologies for centrifugal compressors fall into two main categories: active control and passive control. Active control uses external equipment to sense the compressor's internal flow field in real time and dynamically adjust compressor operating parameters or geometry to proactively suppress flow instabilities. However, active control requires precise prediction of the compressor's flow state, which is challenging, and the early warning and control systems are relatively complex. Therefore, active control technology is still in the laboratory research stage. Passive control technology involves designing and modifying the existing blade tip shape and casing structure to achieve targeted flow control. These include tip winglets, vortex generators, and casing treatments. Casing treatments are widely used in engineering due to their simple structure, ease of fabrication, high reliability, and excellent stabilization. Grooved and slotted casing treatments are small-scale control technologies primarily used in axial-flow compressors. However, their stabilization effect is less pronounced in centrifugal compressors, where self-circulating casing treatments are often employed. However, when the compressor is operating under the designed working conditions, the self-circulating casing treatment will inevitably bring additional flow losses, resulting in a decrease in compressor efficiency. How to reduce the impact on the compressor efficiency when using the self-circulating casing has become one of the technical problems that technical personnel in this field urgently need to solve. Summary of the Invention

[0003] In view of this, an embodiment of the present invention provides a centrifugal compressor self-circulation casing and a centrifugal compressor, so as to reduce the impact on the efficiency of the compressor when using the self-circulation casing.

[0004] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0005] A centrifugal compressor self-circulating casing, comprising:

[0006] A self-circulating casing channel group, wherein the self-circulating casing channel group corresponds one-to-one to the blade channels of the centrifugal compressor;

[0007] Each self-circulating casing channel group includes N self-circulating casing channels, where N is a positive integer not less than 2;

[0008] The air jet of the self-circulating casing channel is located at the leading edge of the main blade of the centrifugal compressor;

[0009] Each self-circulating casing channel in the self-circulating casing channel group has at least one different design parameter, wherein the design parameter at least includes the position of the air bleed port;

[0010] A rotatable gasket is provided with through holes corresponding one to one with the self-circulation receiver channel group. By rotating the rotatable gasket, the through hole can be switched within the N self-circulation receiver channels in the self-circulation receiver channel group, so that the self-circulation receiver channel cut by the through hole enters an enabled state, while the other self-circulation receiver channels are in an unenabled state.

[0011] Optionally, the centrifugal compressor self-circulating casing includes:

[0012] The self-circulating casing channel group includes a first self-circulating casing channel, a second self-circulating casing channel and a third self-circulating casing channel;

[0013] The air bleed port of the first self-circulating casing channel is located at a first axial chord length position, the air bleed port of the second self-circulating casing channel is located at a second axial chord length position, and the air bleed port of the third self-circulating casing channel is located at a third axial chord length position, wherein the first axial chord length is greater than the second axial chord length, and the second axial chord length is greater than the third axial chord length;

[0014] The bridge section length of the first self-circulating casing channel is a first length, the bridge section length of the second self-circulating casing channel is a second length, and the bridge section length of the third self-circulating casing channel is a third length, wherein the first length is greater than the second length, and the second length is greater than the third length.

[0015] Optionally, in the above-mentioned centrifugal compressor self-circulation casing, the first axial chord length position is located within the first axial chord length range, the second axial chord length position is located within the second axial chord length range, the third axial chord length position is located within the third axial chord length range, the minimum value of the first axial chord length range is greater than the maximum value of the second axial chord length range, and the minimum value of the second axial chord length range is greater than the maximum value of the third axial chord length range.

[0016] Optionally, in the above-mentioned centrifugal compressor self-circulating casing, the minimum value of the first axial chord length range is not less than 78% of the axial chord length, and the maximum value is not greater than 84% of the axial chord length;

[0017] The minimum value of the second axial chord length range is not less than 47% of the axial chord length, and the maximum value is not greater than 53% of the axial chord length;

[0018] The minimum value of the third axial chord length range is not less than 35% of the axial chord length, and the maximum value is not greater than 41% of the axial chord length.

[0019] Optionally, in the above-mentioned centrifugal compressor self-circulation casing, the jet port position of each self-circulation casing channel in the self-circulation casing channel group is located within the fourth axial chord length range, and the maximum value in the fourth axial chord length range is not greater than the minimum value in the third axial chord length range;

[0020] The jet outlet angle of the self-circulating casing channel is within a first angle range;

[0021] The air bleed port angle of the self-circulating casing channel is within a second angle range;

[0022] The throat height of the self-circulating casing channel is within a first height range;

[0023] The circumferential coverage of the self-circulating casing channel is a first coverage;

[0024] The circumferential offset angle of the self-circulating casing channel is a first angle value;

[0025] The bridge section height of the self-circulating casing channel is within a second height range.

[0026] Optionally, in the above-mentioned centrifugal compressor self-circulating casing, the minimum value of the fourth axial chord length range is not less than 3% of the axial chord length, and the maximum value is not more than 6% of the axial chord length;

[0027] The minimum value of the first angle range is not less than 10° and the maximum value is not more than 20°;

[0028] The minimum value of the second angle range is not less than 15° and the maximum value is not more than 40°;

[0029] The minimum value of the first height range is not less than 1.5 times the blade tip clearance, and the maximum value is not more than 3 times the blade tip clearance;

[0030] The first coverage rate is not less than 5%;

[0031] The first angle value is 55.56°;

[0032] The minimum value of the second height range is not less than 6 times the blade tip clearance, and the maximum value is not more than 10 times the blade tip clearance.

[0033] Optionally, in the above-mentioned centrifugal compressor self-circulation casing, the rotatable gasket passes through the bridge section of the self-circulation casing channel, and the axial surface of the rotatable gasket is perpendicular to the bridge section of the self-circulation casing channel;

[0034] When the through hole on the rotatable gasket is docked with the bridge section, the self-circulation casing channel corresponding to the bridge section enters an activated state.

[0035] Optionally, in the above-mentioned centrifugal compressor self-circulation casing, the centrifugal compressor self-circulation casing further includes a slide rod and a motor;

[0036] The output shaft of the motor is rigidly connected to the first end of the slide rod, and the second end of the slide rod is connected to a bevel gear;

[0037] The rotatable gasket is provided with a gear structure matching the bevel gear, and the bevel gear and the rotatable gasket gear structure are meshed with each other, so that when the motor drives the slide bar to rotate, the rotatable gasket is driven to rotate through the gear structure.

[0038] A centrifugal compressor comprises the centrifugal compressor self-circulation casing described in any one of the above.

[0039] Optionally, in the above-mentioned centrifugal compressor, when the centrifugal compressor self-circulation casing is the centrifugal compressor self-circulation casing described above, the controller of the centrifugal compressor is further used to obtain the flow value of the centrifugal compressor;

[0040] determining a target self-circulating casing channel based on the flow value;

[0041] A control signal is output to the motor, wherein the control signal is used to control the motor to drive the rotatable gasket to rotate, so that the target self-circulation casing channel enters an activated state.

[0042] Based on the above technical solution, the above solution provided by the embodiment of the present invention is that the self-circulation casing of the centrifugal compressor has a self-circulation casing channel group, and the self-circulation casing channel group includes N self-circulation casing channels, and each self-circulation casing channel has at least one different design parameter, and the design parameter at least includes the position of the air bleed port. By configuring different air bleed port positions for each self-circulation casing channel, different self-circulation casing channels are adapted to different compressor working conditions. By switching the enabled self-circulation casing channel through a rotatable gasket, the compressor can enable different self-circulation casing channels under different working conditions, so that the compressor using the self-circulation casing channel group can maintain a higher efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0044] Figure 1 A schematic structural diagram of a self-circulating casing channel group provided in an embodiment of the present application;

[0045] Figure 2 A front view of the installation method of the self-circulating casing channel group provided in an embodiment of the present application;

[0046] Figure 3 A top view of the installation method of the self-circulating casing channel group provided in an embodiment of the present application;

[0047] Figure 4 This is a schematic structural diagram of the self-circulating casing channel included in the self-circulating casing channel group disclosed in an embodiment of the present application;

[0048] Figure 5 This is a schematic diagram of the arrangement of the self-circulating casing channel disclosed in another embodiment of the present application;

[0049] Figure 6 A schematic structural diagram of a rotatable gasket disclosed in an embodiment of the present application;

[0050] Figure 7 Schematic diagram of the driving method of the rotatable gasket disclosed in the embodiment of the present application;

[0051] Figure 8 This is a structural schematic diagram of a self-circulating casing channel group disclosed in another embodiment of the present application;

[0052] Figure 9 A schematic diagram of a simulation process of a self-circulating casing channel disclosed in an embodiment of the present application;

[0053] Figure 10 This is a schematic structural diagram of the self-circulating casing channel disclosed in an embodiment of the present application;

[0054] Figure 11 A schematic diagram of simulation results provided in an embodiment of the present application;

[0055] Figure 12 This is another schematic diagram of simulation results provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0057] This application solves the flow instability problem of centrifugal compressors under small flow conditions by utilizing self-circulating casing stabilization technology, and proposes an adjustable self-circulating casing and a split design and processing method to meet the different working condition control requirements of the compressor, improve the operating efficiency and stable working margin of the compressor, and greatly reduce the processing difficulty and operation and maintenance costs.

[0058] Specifically, this embodiment provides a centrifugal compressor self-circulating casing, see Figure 1 , which includes: self-circulating casing channel group 10, see Figure 2 and Figure 3 , Figure 3 02 is the casing surface, and the self-circulating casing channel group corresponds to the blade channel 01 of the centrifugal compressor one by one. Each self-circulating casing channel group includes N self-circulating casing channels, where N is a positive integer not less than 2. For example, see Figure 4 The self-circulation casing channel group may include a first self-circulation casing channel 11, a second self-circulation casing channel 12, and a third self-circulation casing channel 13; at least one design parameter of each self-circulation casing channel in the self-circulation casing channel group is different, and the design parameter at least includes the position of the air bleed port;

[0059] See also Figure 5 , Figure 5 20 is a rotatable gasket, 03 is a compressor casing, 04 is a compressor hub surface, 05 is a compressor hub, a represents a self-circulating casing channel, in this embodiment, the centrifugal compressor self-circulating casing further includes a rotatable gasket 20, see Figure 6 The rotatable gasket is provided with through holes corresponding one to one with the self-circulation receiver channel group. By rotating the rotatable gasket, the through hole can be switched among the N self-circulation receiver channels in the self-circulation receiver channel group, so that the self-circulation receiver channel cut by the through hole enters the enabled state, while the other self-circulation receiver channels are in the unenabled state.

[0060] This embodiment provides a solution for freely rotating the rotatable gasket. Specifically, the bridge section can be formed by splicing gaskets arranged side by side, one of which is a rotatable gasket. The rotation of the rotatable gasket is controlled by an external small motor. Figure 7The motor is connected to a slide rod, and the other end of the slide rod is connected to a bevel gear. In addition, a certain number of bevel gears are also processed on the rotatable gasket. The range of the bevel gears can cover 45° or other circumferential angles. The bevel gears on the rotatable gasket cooperate with the bevel gears on the slide rod. The rotation of the motor drives the rotation of the bevel gears, and under the action of the bevel gear meshing structure, the rotation of the gasket is driven. A mode can be switched every time a certain angle is rotated (such as 11.25°). There are four modes in total. Mode 1 is to close the self-circulating receiver channel (the first self-circulating receiver channel, the second self-circulating receiver channel, and the third self-circulating receiver channel are all in the disabled state), Mode 2 is to open the first self-circulating receiver channel, Mode 3 is to open the second self-circulating receiver channel, and Mode 4 is to open the third self-circulating receiver channel.

[0061] In the above scheme of the present application, the self-circulation casing channel group includes N self-circulation casing channels, and each self-circulation casing channel has at least one different design parameter, and the design parameter at least includes the position of the air bleed port. By configuring different air bleed port positions for each self-circulation casing channel, different self-circulation casing channels are adapted to different compressor operating conditions. By switching the enabled self-circulation casing channels through a rotatable gasket, the compressor can enable different self-circulation casing channels under different operating conditions, so that the compressor using the self-circulation casing channel group can maintain a higher efficiency.

[0062] The technical solutions disclosed in the above embodiments of this application are shown in Figure 8 The centrifugal compressor has a hub surface, on which main blades 06 and splitter blades 07 are arranged. The jet port 101 of the self-circulating casing channel is located at the leading edge of the main blade 06. The positions of the jet port 101 and the air inlet 102 can be set according to needs. For example, the jet port 101 is located on the side of the main blade 06 facing the splitter blade 07, and the air inlet 102 of the self-circulating casing channel is located on the side of the main blade 06 away from the splitter blade 07. When a certain self-circulating casing channel enters the starting state by rotating the rotatable gasket, compressed air enters through its air inlet and passes through the self-circulating casing channel. After being accelerated, it is ejected from its jet port 101. Since the jet port 101 is located near the leading edge of the main blade, the high-speed jet ejected from the jet port changes the flow direction of the leakage flow of the centrifugal compressor, reduces the axial angle of the leakage flow, and thus reduces the obstruction of the leakage flow to the mainstream. At the same time, the high-speed airflow ejected from the jet port also impacts the recirculation zone propagating from the leading edge area of the splitter blade to the leading edge area of the main blade, causing it to move to a further downstream position. In addition, the air inlet also has a suction effect on the low-energy fluid, thereby extracting the low-flow rate gas in the centrifugal compressor, making the gas flow rate in the centrifugal compressor basically stable, thereby greatly improving the stable operating range of the centrifugal compressor.

[0063] In order to provide a self-circulating casing channel with better effect, this application uses a three-dimensional simulation model to design the self-circulating casing channel. Figure 9 The specific process includes:

[0064] Step S1: construct a three-dimensional model of the compressor and perform full-operating-condition simulation analysis to obtain the distribution of flow losses inside the compressor under various operating conditions.

[0065] Specifically, this step first establishes a three-dimensional numerical model for the solid-wall casing compressor, and performs simulation analysis of target operating conditions based on the three-dimensional numerical model. The target operating conditions include three typical operating conditions: near-blockage, near-stall, and design conditions. The flow characteristics inside the compressor under these three conditions are obtained, and a block quantification method is used to analyze the distribution of flow losses inside the compressor under different operating conditions.

[0066] Step S2: Based on the internal loss distribution of the compressor, the positions of the air injection port and the air bleed port of the self-circulating casing are determined, and according to the different loss distributions under different working conditions, the design schemes of the air injection port and the air bleed port positions of the self-circulating casing corresponding to different working conditions are proposed.

[0067] For example, according to the internal loss distribution of the compressor under the above three working conditions, three self-circulating casing schemes with different injection port and air inlet positions are set up respectively, and the three schemes are numerically simulated.

[0068] Step S3: The five factors of the self-circulating casing, namely, the jet port, the air bleed port angle, the throat height, the circumferential coverage rate, and the circumferential offset angle, are used as the five factors of the DOE experimental design. The isentropic efficiency and the improvement of the comprehensive stall margin are used as the two response values. The corresponding numerical simulation is carried out according to the DOE experimental sequence, and the response surface analysis is performed on the simulation results to obtain the optimal structure of the self-circulating casing scheme corresponding to each target operating condition.

[0069] Step S4: Perform numerical simulation on each optimized self-circulating casing structure to verify the correctness of the optimization results.

[0070] When verifying the correctness of the optimization results, the present invention can use the following comprehensive indicators to quantitatively evaluate the optimization effect:

[0071] Comprehensive stall margin improvement:

[0072] ;

[0073] Where: and are the near-stall flow rates of the centrifugal compressors before and after the self-circulating casing treatment, and They are the total pressure ratios near the stall point of the centrifugal compressor before and after self-circulating casing treatment.

[0074] In the self-circulating casing solution provided by the present invention, the high-speed jet ejected from the self-circulating casing air outlet changes the flow direction of the leakage flow, reduces its axial angle, and weakens the obstruction to the mainstream; at the same time, it also impacts the recirculation zone propagating from the leading edge area of the splitter blade to the leading edge area of the main blade, causing it to move to a more downstream position; in addition, the air inlet also has a suction effect on the low-energy fluid, thereby greatly improving the stable operating range of the centrifugal compressor.

[0075] The applicant further used numerical simulation to verify and demonstrate the stabilization effect of the self-circulating casing. During the verification, the supercritical carbon dioxide centrifugal compressor used had 8 channels. In order to save computing costs, a single channel was selected for numerical simulation. Specifically, TurboGrid in the CFX software was used to perform structured mesh division on the impeller and diffuser, and the self-circulating casing was modeled on the basis of the prototype compressor using UG. After the modeling was completed, it was imported into ICEM for structured mesh division. The divided compressor and self-circulating casing meshes were imported into the CFX pre-processing. The compressor and the self-circulating casing used the frozen rotor method, the compressor outlet boundary condition used the static pressure outlet, and the turbulence model used SST (Shear Stress Transfer). Then, CFD-post was used to post-process the numerical calculation results to obtain the comprehensive stall margin improvement of the self-circulating casing.

[0076] After verifying the correctness of the self-circulating casing structure, the self-circulating casing can be processed by the split processing method, see Figure 10 The self-circulating casing is divided into three sections: the jet section L1, the bridge section L2, and the air bleed section L3. The angle between the head end of the air bleed section and the casing surface is the air bleed angle θ1, and the angle between the end of the jet section and the casing surface is the jet angle θ2. The jet section and the air bleed section are processed in an integrated manner. The bridge section can be composed of multiple annular gaskets with different inner circle radii. One of these gaskets can be used as the rotatable gasket in this application. The processing technology can adopt the five-axis linkage technology of CNC machine tools. The air bleed section and the jet section can adopt a uniform cross-section arc structure.

[0077] In this embodiment, see Figure 4The self-circulating casing channel group includes a first self-circulating casing channel, a second self-circulating casing channel and a third self-circulating casing channel, and these three channels correspond to different flow conditions of the centrifugal compressor respectively; wherein, the air bleed port of the first self-circulating casing channel is located at the first axial chord length position, the air bleed port of the second self-circulating casing channel is located at the second axial chord length position, and the air bleed port of the third self-circulating casing channel is located at the third axial chord length position, wherein, the first axial chord length is greater than the second axial chord length, and the second axial chord length is greater than the third axial chord length; the bridge section length of the first self-circulating casing channel is the first length, the bridge section length of the second self-circulating casing channel is the second length, and the bridge section length of the third self-circulating casing channel is the third length, wherein, the first length is greater than the second length, and the second length is greater than the third length. By reasonably planning the position of the air bleed port of the self-circulating casing channel and configuring the position of the jet port according to the bridge section length of the self-circulating casing channel, the self-circulating casing channel can adapt to the internal loss distribution of the centrifugal compressor under various flow conditions.

[0078] In this embodiment, the present application can set the position of the air bleed port according to the internal loss distribution of the centrifugal compressor under the flow conditions corresponding to the above-mentioned three channels. Specifically, the three flow conditions corresponding to the design scheme disclosed in the present application are flow conditions of 7.3~10.5kg / s, 10.5~13kg / s and 14.5~20.5kg / s, respectively. The internal loss distribution area of the centrifugal compressor under these three flow conditions is a range value. Therefore, the position of the air bleed port can be any position within the range value. For example, the first axial chord length position is within the first axial chord length range, the second axial chord length position is within the second axial chord length range, and the third axial chord length position is within the third axial chord length range. The minimum value of the first axial chord length range is greater than the maximum value of the second axial chord length range, and the minimum value of the second axial chord length range is greater than the maximum value of the third axial chord length range. Specifically, the minimum value of the first axial chord length range is not less than 78% of the axial chord length, and the maximum value is not greater than 84% of the axial chord length; the minimum value of the second axial chord length range is not less than 47% of the axial chord length, and the maximum value is not greater than 53% of the axial chord length; the minimum value of the third axial chord length range is not less than 35% of the axial chord length, and the maximum value is not greater than 41% of the axial chord length.

[0079] In this solution, in addition to setting the position of the air bleed port, other parameters of the self-circulating casing channel also need to be set. The selection range of other parameters can be obtained based on the simulation results. Specifically:

[0080] The jet port position of each self-circulating casing channel in the self-circulating casing channel group is located within the fourth axial chord length range, and the maximum value in the fourth axial chord length range is not greater than the minimum value in the third axial chord length range;

[0081] The jet outlet angle of the self-circulating casing channel is within a first angle range;

[0082] The air bleed port angle of the self-circulating casing channel is within a second angle range;

[0083] The throat height of the self-circulating casing channel is within a first height range;

[0084] The circumferential coverage of the self-circulating casing channel is a first coverage;

[0085] The circumferential offset angle of the self-circulating casing channel is a first angle value;

[0086] The bridge section height of the self-circulating casing channel is within a second height range.

[0087] More specifically, further, after simulation verification, the minimum value of the fourth axial chord length range is not less than 3% of the axial chord length, and the maximum value is not greater than 6% of the axial chord length; the minimum value of the first angle range is not less than 10°, and the maximum value is not greater than 20°; the minimum value of the second angle range is not less than 15°, and the maximum value is not greater than 40°; the minimum value of the first height range is not less than 1.5 times the blade tip clearance, and the maximum value is not greater than 3 times the blade tip clearance; the first coverage rate is not less than 5%; the first angle value is 55.56°; the minimum value of the second height range is not less than 6 times the blade tip clearance, and the maximum value is not greater than 10 times the blade tip clearance.

[0088] In this embodiment, each blade channel corresponds to a self-circulation casing channel group, and each self-circulation casing channel group includes multiple self-circulation casing channels. For example, each self-circulation casing channel group mentioned above includes three self-circulation casing channels. The user can choose to connect to any one channel in the self-circulation casing channel group and enable the connected channel according to the current flow of the centrifugal compressor. Of course, all of these channels can also be disabled. In order to enable the user to independently choose which channel to enable, the rotatable gasket in the above scheme passes through the radial direction of the bridge section of the self-circulation casing channel (the surface of the rotatable gasket is perpendicular to the axial direction of the bridge section), and the axial surface of the rotatable gasket is perpendicular to the bridge section of the self-circulation casing channel; the user can rotate the rotatable gasket to switch between the channels in the self-circulation casing channel group through the through hole on the rotatable gasket. When the through hole on the rotatable gasket is docked with the bridge section of a self-circulation casing channel, the self-circulation casing channel corresponding to the bridge section enters the enabled state. The bridge sections of other channels are butted against the gasket surface of the rotatable gasket and cannot be conducted, that is, they are in an inactive state.

[0089] Furthermore, this embodiment also discloses a centrifugal compressor, which includes the centrifugal compressor self-circulation casing described in any one of the above.

[0090] When the self-circulating casing channel group includes the above-mentioned first self-circulating casing channel, the second self-circulating casing channel and the third self-circulating casing channel, and the configuration parameters of the first self-circulating casing channel, the second self-circulating casing channel and the third self-circulating casing channel are as follows: the minimum value of the first axial chord length range is not less than 78% of the axial chord length, and the maximum value is not more than 84% of the axial chord length; the minimum value of the second axial chord length range is not less than 47% of the axial chord length, and the maximum value is not more than 53% of the axial chord length; the minimum value of the third axial chord length range is not less than 3 5% of the axial chord length, the maximum value is not more than 41% of the axial chord length; the minimum value of the first angle range is not less than 10°, and the maximum value is not more than 20°; the minimum value of the second angle range is not less than 15°, and the maximum value is not more than 40°; the minimum value of the first height range is not less than 1.5 times the blade tip clearance, and the maximum value is not more than 3 times the blade tip clearance; the first coverage rate is not less than 5%; the first angle value is 55.56°; the minimum value of the second height range is not less than 6 times the blade tip clearance, and the maximum value is not more than 10 times the blade tip clearance. When the comprehensive stall margin improvements of the first self-circulation casing channel, the second self-circulation casing channel and the third self-circulation casing channel are 19.4%, 14.84% and 11.39% respectively, Figure 11 and Figure 12It was found that when the flow rate of the centrifugal compressor is between 7.3 and 10.5 kg / s, the centrifugal compressor using the first self-circulation casing channel has the highest efficiency; when the flow rate of the centrifugal compressor is between 10.5 and 13 kg / s, the centrifugal compressor using the second self-circulation casing channel has the highest efficiency; when the flow rate of the compressor is between 13 and 14.5 kg / s, the efficiency of the prototype centrifugal compressor (the first self-circulation casing channel, the second self-circulation casing channel and the third self-circulation casing channel are not enabled) is the highest; when the flow rate of the compressor is between 14.5 and 20.5 kg / s, the centrifugal compressor using the third self-circulation casing channel has the highest efficiency. Therefore, in order to make the centrifugal compressor more efficient, the present application can select different self-circulation casing channels under different centrifugal compressor flow conditions. Specifically, the controller of the centrifugal compressor is also used to obtain the flow value of the centrifugal compressor; determine the target self-circulation casing channel based on the flow value; and output a control signal to the motor, the control signal being used to control the motor to drive the rotatable gasket to rotate so that the target self-circulation casing channel enters an enabled state.

[0091] For the convenience of description, the above system is described as being divided into various modules according to their functions. Of course, when implementing the present invention, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0092] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0093] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0094] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0095] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0096] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A centrifugal compressor self-circulating casing, characterized in that: include: A self-circulating casing channel group, wherein the self-circulating casing channel group corresponds one-to-one to the blade channels of the centrifugal compressor; Each self-circulating casing channel group includes N self-circulating casing channels, where N is a positive integer not less than 2; The air jet of the self-circulating casing channel is located at the leading edge of the main blade of the centrifugal compressor; Each self-circulating casing channel in the self-circulating casing channel group has at least one different design parameter, wherein the design parameter at least includes the position of the air bleed port; A rotatable gasket is provided with through holes corresponding one to one with the self-circulation receiver channel group. By rotating the rotatable gasket, the through hole can be switched within the N self-circulation receiver channels in the self-circulation receiver channel group, so that the self-circulation receiver channel cut by the through hole enters an enabled state, while the other self-circulation receiver channels are in an unenabled state.

2. The centrifugal compressor self-circulation casing according to claim 1, characterized in that: include: The self-circulating casing channel group includes a first self-circulating casing channel, a second self-circulating casing channel and a third self-circulating casing channel; The air bleed port of the first self-circulating casing channel is located at a first axial chord length position, the air bleed port of the second self-circulating casing channel is located at a second axial chord length position, and the air bleed port of the third self-circulating casing channel is located at a third axial chord length position, wherein the first axial chord length is greater than the second axial chord length, and the second axial chord length is greater than the third axial chord length; The bridge section length of the first self-circulating casing channel is a first length, the bridge section length of the second self-circulating casing channel is a second length, and the bridge section length of the third self-circulating casing channel is a third length, wherein the first length is greater than the second length, and the second length is greater than the third length.

3. The centrifugal compressor self-circulation casing according to claim 2, characterized in that: The first axial chord length position is located within a first axial chord length range, the second axial chord length position is located within a second axial chord length range, and the third axial chord length position is located within a third axial chord length range. The minimum value of the first axial chord length range is greater than the maximum value of the second axial chord length range, and the minimum value of the second axial chord length range is greater than the maximum value of the third axial chord length range.

4. The centrifugal compressor self-circulation casing according to claim 3, characterized in that: The minimum value of the first axial chord length range is not less than 78% of the axial chord length, and the maximum value is not greater than 84% of the axial chord length; The minimum value of the second axial chord length range is not less than 47% of the axial chord length, and the maximum value is not greater than 53% of the axial chord length; The minimum value of the third axial chord length range is not less than 35% of the axial chord length, and the maximum value is not greater than 41% of the axial chord length.

5. The centrifugal compressor self-circulation casing according to claim 4, characterized in that: The jet port position of each self-circulating casing channel in the self-circulating casing channel group is located within the fourth axial chord length range, and the maximum value in the fourth axial chord length range is not greater than the minimum value in the third axial chord length range; The jet outlet angle of the self-circulating casing channel is within a first angle range; The air bleed port angle of the self-circulating casing channel is within a second angle range; The throat height of the self-circulating casing channel is within a first height range; The circumferential coverage of the self-circulating casing channel is a first coverage; The circumferential offset angle of the self-circulating casing channel is a first angle value; The bridge section height of the self-circulating casing channel is within a second height range.

6. The centrifugal compressor self-circulation casing according to claim 5, characterized in that: The minimum value of the fourth axial chord length range is not less than 3% of the axial chord length, and the maximum value is not greater than 6% of the axial chord length; The minimum value of the first angle range is not less than 10° and the maximum value is not more than 20°; The minimum value of the second angle range is not less than 15° and the maximum value is not more than 40°; The minimum value of the first height range is not less than 1.5 times the blade tip clearance, and the maximum value is not more than 3 times the blade tip clearance; The first coverage rate is not less than 5%; The first angle value is 55.56°; The minimum value of the second height range is not less than 6 times the blade tip clearance, and the maximum value is not more than 10 times the blade tip clearance.

7. The centrifugal compressor self-circulation casing according to claim 1, characterized in that: The rotatable gasket passes through the bridge section of the self-circulating casing channel, and the axial surface of the rotatable gasket is perpendicular to the bridge section of the self-circulating casing channel; When the through hole on the rotatable gasket is docked with the bridge section, the self-circulation casing channel corresponding to the bridge section enters an activated state.

8. The centrifugal compressor self-circulation casing according to claim 7, characterized in that: The centrifugal compressor self-circulation casing also includes a slide rod and a motor; The output shaft of the motor is rigidly connected to the first end of the slide rod, and the second end of the slide rod is connected to a bevel gear; The rotatable gasket is provided with a gear structure matching the bevel gear, and the bevel gear and the gear structure of the rotatable gasket are meshed with each other, so that when the motor drives the slide bar to rotate, the rotatable gasket is driven to rotate through the gear structure.

9. A centrifugal compressor, characterized in that: The invention comprises a self-circulating casing of a centrifugal compressor according to any one of claims 1 to 8.

10. The centrifugal compressor according to claim 9, characterized in that When the centrifugal compressor self-circulation casing is the centrifugal compressor self-circulation casing according to claim 8, the controller of the centrifugal compressor is further used to obtain the flow value of the centrifugal compressor; determining a target self-circulating casing channel based on the flow value; A control signal is output to the motor, wherein the control signal is used to control the motor to drive the rotatable gasket to rotate, so that the target self-circulation casing channel enters an activated state.

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