CN118066122B - Improved generation high-lift cryogenic pump cavitation prevention impeller and performance verification device - Google Patents
Improved generation high-lift cryogenic pump cavitation prevention impeller and performance verification device Download PDFInfo
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- 238000012806 monitoring device Methods 0.000 claims abstract description 20
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Abstract
The invention relates to the technical field of impeller cavitation, in particular to an improved cavitation prevention impeller of a high-lift cryogenic pump and a performance verification device, which comprises an induction pressurizing assembly and a flow control device for pressurizing the front end of a multistage impeller shaft, and a pressure monitoring device for measuring the pressure at the front end of a multistage wheel shaft.
Description
Technical Field
The invention relates to the technical field of impeller cavitation, in particular to an improved cavitation prevention impeller of a high-lift low-temperature pump and a performance verification device.
Background
Cavitation of centrifugal pump impellers is a complex physical phenomenon that is primarily related to the flow characteristics and pressure variations of the liquid in the pump. When a liquid flows in a centrifugal pump, if its pressure is reduced to a certain extent, the formation, development and collapse of vapor pockets or bubbles, which are so-called cavitation, occur inside the liquid or at the liquid-solid interface. Cavitation occurs for a variety of reasons including excessive resistance of the inlet conduit or tubule, excessive temperature of the transport medium, excessive flow, excessive mounting height, and improper selection of pumps and materials. These factors may all lead to a decrease in the pressure of the liquid in the pump, thereby inducing cavitation. Centrifugal pump impeller cavitation may be inhibited by modifying the impeller structure to optimize flow characteristics, including methods of improving the impeller inlet portion finish, optimizing impeller geometry, blade slotting or blade aperturing, disposing obstructions or splitter blades, and the like.
The phenomenon of low Wen Konghua is liquid vaporization phenomenon widely existing in LNG transportation, liquid hydrogen filling, large-scale air separation equipment and systems, liquid rocket launching and other low-temperature systems. The low-temperature centrifugal pump usually plays a role of a heart of the system, and the cavitation phenomenon in the low-temperature centrifugal pump directly determines the stability and reliability of low-temperature process equipment and the system. Because the flow channel has a complex structure and a plurality of influencing factors, cavitation of the low-temperature centrifugal pump is a difficult problem puzzling the development of the industry, and not only affects the hydrodynamic performance of the low-temperature pump, but also causes high-amplitude structural oscillation. Because the working medium conveyed by the low-temperature centrifugal pump is special, the working medium comprises cryogenic liquids such as liquid oxygen, liquid hydrogen, LNG and the like. The liquid medium has small vaporization latent heat, the saturation temperature is far lower than the ambient temperature, vaporization inevitably occurs in the conveying process to form a vapor-liquid two-phase form, and the vapor-liquid two-phase form interacts with cavitation bubbles in the pump to influence the hydrodynamic performance and cavitation performance of the pump to a certain extent. In order to prevent and control the low-temperature cavitation of the centrifugal pump, a calculation method of the low-temperature cavitation is required to be mastered, the cavitation performance of the centrifugal pump is accurately predicted, and in the prior art, when the structures of the centrifugal pump and the impeller are improved, a large number of experience parameters are required to be set in a computer simulation mode, so that verification equipment for simulating actual use conditions is required to test the cavitation performance of the impeller.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides an improved anti-cavitation impeller of a high-lift low-temperature pump and a performance verification device, wherein an adjustable external auxiliary pressure is provided for an impeller inlet through an induction pressurizing assembly, and a critical value of cavitation initiation is detected through a pressure monitoring device, so that the structure of the impeller can be continuously verified and improved, and the design requirement of the anti-cavitation impeller of the high-lift low-temperature pump is met.
In order to achieve the above purpose, the present invention provides the following technical solutions:
The anti-cavitation impeller performance verification device of the high-lift low-temperature pump comprises an induction and pressurization assembly for pressurizing the front end of a multistage impeller shaft, a flow control device and a pressure monitoring device for measuring the pressure at the front end of a multistage impeller shaft, wherein the multistage impeller shaft is rotatably supported in a test pump body and is in transmission connection with an impeller motor through a first coupling, and the multistage impeller shaft is driven to rotate through the impeller motor and reaches a preset rotating speed to match the rated power of the high-lift low-temperature pump; the induced pressurizing assembly is connected with the test pump body through a flow control device, and the flow control device can control the flow of fluid conveyed from the induced pressurizing assembly to the test pump body so as to control the pressure at the front end of the multistage impeller shaft in the test pump body; the pressure monitoring device is arranged in the test pump body and is positioned near the front end of the multistage impeller shaft so as to obtain the pressure at the impeller inlet of the multistage impeller shaft, the multistage impeller shaft is accelerated to a preset rotating speed, and the pressure obtained by the pressure monitoring device is not lower than the pressure critical value of cavitation initiation, and the pressure assembly and the flow control device are induced to provide external auxiliary pressure as low as possible to the front end of the multistage impeller shaft so as to verify the cavitation resistance of the multistage impeller shaft.
Further, the induction pressurizing assembly comprises a support shell, two ends of the induction wheel shaft are rotatably supported in the support shell through sealing bearings, and a low-pressure port and a high-pressure port which are perpendicular to the induction wheel shaft are respectively arranged at two ends of the support shell; the induction wheel shaft is provided with a spiral inducer, the inducer motor is in transmission connection with the induction wheel shaft through a second coupler, and the inducer motor drives the spiral inducer to rotate so as to pressurize fluid entering from the low-pressure port and flow from the high-pressure port to the flow control device.
Further, the flow control device comprises a support valve body, a valve rod driving part, a valve rod control part, a rotary valve core, a first connecting flange and a second connecting flange; the support valve body is connected with a high-pressure port of the induced pressurizing assembly through a first connecting flange, and is connected with an inlet of the test pump body through a second connecting flange; the rotary valve core is rotatably arranged in the spherical cavity in the supporting valve body, the rotary valve core is connected with the valve rod driving part through the valve rod, and the valve rod control part controls the valve rod driving part to drive the rotary valve core to rotate so as to control the pressure of fluid flowing from the induced pressurizing assembly to the testing pump body.
Further, the rotary valve core comprises a spherical shell, a first V-shaped opening, a second V-shaped opening, a rotary supporting end and a valve rod connecting end; one end of the spherical shell is connected with the valve rod through a valve rod connecting end, and the other end of the spherical shell is supported in a spherical cavity for supporting the valve body through a rotary supporting end; the two opposite sides of the spherical shell are respectively provided with a first V-shaped opening and a second V-shaped opening, and the tip directions of the first V-shaped opening and the second V-shaped opening are consistent with the rotation direction of the spherical shell.
Further, the multistage impeller shaft comprises a driving shaft, impellers, an adjusting sleeve and a balance disc, two ends of the driving shaft are rotatably arranged in the test pump body through sealing bearings, the driving shaft is in transmission connection with an impeller motor through a first coupling, the driving shaft sleeve is provided with multistage impellers, the final-stage impellers are abutted against the adjusting sleeve, and the balance disc is arranged on the other side of the adjusting sleeve; an inlet and an outlet are arranged on the supporting shell of the test pump body, and fluid enters the test pump body through the inlet, then enters the first-stage impeller through the impeller inlet and is pressurized.
Further, a pressure sensor of the pressure monitoring device is arranged at an impeller inlet of the test pump body, and the pressure of the fluid is obtained through the pressure sensor and recorded in the measuring instrument; the multistage impeller shaft is driven to a preset rotating speed, the pressure of fluid in an impeller inlet is obtained in real time through a pressure sensor, and current test data are recorded through a measuring instrument when a measured value obtained by the pressure sensor reaches a pressure critical value of cavitation primary in the process of controlling the induced pressurizing assembly and the flow control device to gradually reduce auxiliary pressure of the inlet of the test pump body.
The improved cavitation prevention impeller of the high-lift cryogenic pump is characterized in that the performance of the cavitation prevention structure on the impeller is verified through the performance verification device, the impeller comprises a rear cover and a front cover, an impeller inlet is formed in the middle of the front cover, a blade group is arranged between the rear cover and the front cover, the blade group is connected with a hub, and fluid enters through the impeller inlet and passes through the hub and is then pressurized and conveyed to a rear cavity of the impeller through the blade group; the rear cover is provided with a plurality of first balance holes, and the hub is provided with a plurality of second balance holes.
Further, the diameter of the impeller inlet on the front cover is D1, the blade group comprises a first blade and a second blade, the first blade extends and is connected to the hub, the second blade and the first blade have the same extending track, and the diameter of a circle formed by the extending termination positions of a plurality of second blades is larger than D1; the positions of the first balance holes fall on the extension line of the second blade, and the diameter D2 of a circle formed by a plurality of the first balance holes is D2> D1.
Further, the hub is provided with bosses the same as the second blades in number, and the extension lines of the second blades extend to the bosses; the boss is provided with a second balance hole, the second balance hole comprises an axial section and a radial section, the axial section is communicated with a rear cavity of the impeller, the radial section is communicated with an impeller inlet of the impeller, and an outlet of the radial section faces to the radial direction of the impeller so as to reduce disturbance of fluid entering the impeller inlet through the second balance hole to a main flow.
The improved performance verification method for the cavitation prevention impeller of the high-lift low-temperature pump verifies the performance of the cavitation prevention impeller, and comprises the following steps:
Step a, controlling an impeller motor to drive a multistage impeller shaft to rotate at a preset rotating speed, wherein the preset rotating speed corresponds to the design power of a high-lift cryogenic pump;
step b, starting an inducer motor to drive an inducer pressurizing assembly to apply a preset auxiliary pressure to the fluid;
Step c, controlling the flow control device to gradually reduce auxiliary pressure output to an inlet of the test pump body by the induction pressurizing assembly, and recording current test data by the measuring instrument when a measured value obtained by a pressure sensor of the pressure monitoring device reaches a pressure critical value of cavitation onset;
And d, replacing impellers with different structures, specifically changing the apertures of the first balance holes, the second balance holes and the positions of the first balance holes, and repeating the steps a to c.
Compared with the prior art, the invention provides an improved cavitation prevention impeller of a high-lift low-temperature pump and a performance verification device, which have the following beneficial effects:
1. according to the invention, the pressure monitoring device monitors whether the pressure at the inlet of the impeller reaches the critical value of cavitation initiation in real time to judge the passing performance of fluid at the impeller and the cavitation prevention performance of the impeller, so that the parameters such as the structure of a blade group of the impeller, the size position of a balance hole and the like can be improved.
2. According to the invention, the arrangement form of the balance holes in the impeller reduces the disturbance to the main flow at the inlet of the impeller, the position of the first balance hole is shielded by the front cover, so that the direct convergence of the fluid passing through the first balance hole to the main flow is avoided, and the verification proves that the first balance hole is arranged on the extension line of the second blade, so that the disturbance to the main flow can be reduced.
3. The hub of the impeller is provided with the second balance hole, and the radial section of the second balance hole enables fluid flowing out of the second balance hole to be converged into the main flow in the same direction, so that the disturbance of the second balance hole to the main flow at the inlet of the impeller is avoided.
Drawings
FIG. 1 is a schematic diagram of the overall structure of an improved cavitation prevention impeller performance verification device for a high-lift cryogenic pump;
FIG. 2 is a schematic diagram of the structure of the induction pressurizing assembly of the present invention;
FIG. 3 is a schematic diagram of a flow control device according to the present invention;
FIG. 4 is a schematic view of a rotary valve core according to the present invention;
FIG. 5 is a schematic view of the structure of the test pump body of the present invention;
FIG. 6 is a schematic view of the impeller of the present invention;
FIG. 7 is a schematic cross-sectional view of an impeller of the present invention;
FIG. 8 is a schematic longitudinal section of the impeller of the present invention;
In the figure:
multistage impeller shaft 1, drive shaft 11, impeller 12, rear cover 121, front cover 122, hub 123, boss 1231, vane set 124, first vane 1241, second vane 1242, first balance hole 125, extension wire 1250, second balance hole 126, axial section 1261, radial section 1262, adjustment sleeve 13, balance disk 14;
The test pump body 2, the support housing 21, the inlet 22, the outlet 23, and the impeller inlet 24;
the flow control device 3, the support valve body 31, the valve stem driving part 32, the valve stem control part 33, the rotary valve core 34, the spherical shell 341, the first V-shaped opening 342, the second V-shaped opening 343, the rotary support end 344, the valve stem connection end 345, the first connection flange 35, the second connection flange 36;
an induction pressurizing assembly 4, a support shell 41, a sealing bearing 42, a low pressure port 43, a high pressure port 44, an induction wheel shaft 45 and a spiral inducer 46;
A pressure monitoring device 5, a pressure sensor 51, a measuring instrument 52;
a first coupling 6; an impeller motor 7; inducer motor 8; a second coupling 9.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Spatially relative terms, such as "above … …," "above … …," "upper surface on … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations "above …" and "below … …". The device may also be positioned in other different ways and the spatially relative descriptions used herein are construed accordingly.
The invention is described in detail below with reference to the accompanying drawings, and the improved cavitation prevention impeller and performance verification device of the high-lift cryogenic pump of the invention comprises an induced pressurizing assembly 4 and a flow control device 3 for pressurizing the front end of a multistage impeller shaft 1, and a pressure monitoring device 5 for measuring the pressure at the front end of the multistage wheel shaft 1, wherein the multistage impeller shaft 1 is rotatably supported in a test pump body 2 and is in transmission connection with an impeller motor 7 through a first coupling 6, and the multistage impeller shaft 1 is driven to rotate through the impeller motor 7 and reaches a preset rotating speed to match the rated power of the high-lift cryogenic pump; the induction pressurizing assembly 4 is connected with the test pump body 2 through a flow control device 3, and the flow control device 3 can control the flow of fluid conveyed from the induction pressurizing assembly 4 to the test pump body 2 so as to control the pressure at the front end of the multistage impeller shaft 1 in the test pump body 2; the pressure monitoring device 5 is arranged in the test pump body 2 and is positioned near the front end of the multistage impeller shaft 1 so as to acquire the pressure at the impeller inlet of the multistage impeller shaft 1, accelerate the multistage impeller shaft 1 to a preset rotating speed, and provide external auxiliary pressure as low as possible for the front end of the multistage impeller shaft 1 through the induction pressurizing assembly 4 and the flow control device 3 on the premise that the pressure acquired by the pressure monitoring device 5 is not lower than a pressure critical value of cavitation initiation so as to verify the cavitation prevention performance of the multistage impeller shaft 1.
The pressure monitoring device 5 monitors whether the pressure at the inlet of the impeller reaches a critical value of cavitation initiation in real time to judge the passing performance of fluid at the impeller 12 and the cavitation prevention performance of the impeller 12, so that the parameters such as the structure of the blade group 124 of the impeller 12, the size position of the balance hole and the like can be improved.
Referring to fig. 2, the induction pressurizing assembly 4 includes a support housing 41, two ends of an induction wheel shaft 45 are rotatably supported in the support housing 41 through a sealing bearing 42, and two ends of the support housing 41 are respectively provided with a low pressure port 43 and a high pressure port 44 perpendicular to the induction wheel shaft 45; the inducer shaft 45 is provided with a spiral inducer 46, the inducer motor 8 is in transmission connection with the inducer shaft 45 through the second coupling 9, and the inducer motor 8 drives the spiral inducer 46 to rotate so as to pressurize the fluid entering from the low pressure port 43 and flow the fluid from the high pressure port 44 to the flow control device 3.
Referring to fig. 3, the flow control device 3 includes a support valve body 31, a valve stem driving part 32, a valve stem control part 33, a rotary spool 34, a first connection flange 35, and a second connection flange 36; the supporting valve body 31 is connected with the high-pressure port 44 of the induced pressurizing assembly 4 through a first connecting flange 35, and the supporting valve body 31 is connected with the inlet 22 of the test pump body 2 through a second connecting flange 36; the rotary valve core 34 is rotatably arranged in the spherical cavity in the support valve body 31, the rotary valve core 34 is connected with the valve rod driving part 32 through a valve rod, the valve rod control part 33 controls the valve rod driving part 32 to drive the rotary valve core 34 to rotate so as to control the pressure of fluid flowing from the induction and pressurization assembly 4 to the test pump body 2, stable external auxiliary pressure can be provided for the test pump body 2 through the induction and pressurization assembly 4, and the flow control device 3 is arranged between the induction and pressurization assembly 4 and the test pump body 2 so as to better regulate the pressure input.
Referring to fig. 4, the rotary spool 34 includes a spherical shell 341, a first V-shaped opening 342, a second V-shaped opening 343, a rotary support end 344, and a valve stem connection end 345; one end of the spherical shell 341 is connected with the valve rod through a valve rod connecting end 345, and the other end of the spherical shell 341 is supported in a spherical cavity supporting the valve body 31 through a rotary supporting end 344; the opposite sides of the spherical shell 341 are respectively provided with a first V-shaped opening 342 and a second V-shaped opening 343, the tip directions of the first V-shaped opening 342 and the second V-shaped opening 343 are consistent with the rotation direction of the spherical shell 341, the rotary valve core 34 is arranged in a spherical structure, the control of the valve rod control part 33 and the valve rod driving part 32 on the rotation amount of the rotary valve core 34 can be facilitated, the first V-shaped opening 342 and the second V-shaped opening 343 arranged on the rotary valve core 34 can enable the flow of the fluid passing through to be controlled more linearly, and further the auxiliary pressure input into the inlet of the test pump body 2 can be controlled more accurately.
Referring to fig. 5, the multistage impeller shaft 1 comprises a driving shaft 11, an impeller 12, an adjusting sleeve 13 and a balance disc 14, wherein two ends of the driving shaft 11 are rotatably arranged in the test pump body 2 through sealing bearings, the driving shaft 11 is in transmission connection with an impeller motor 7 through a first coupling 6, the driving shaft 11 is sleeved with the multistage impeller 12, the impeller 12 of the final stage is abutted against the adjusting sleeve 13, and the balance disc 14 is arranged on the other side of the adjusting sleeve 13; an inlet 22 and an outlet 23 are arranged on the support housing 21 of the test pump body 2, and fluid enters the test pump body 2 through the inlet 22, then enters the first-stage impeller 12 through the impeller inlet 24 and is pressurized.
The pressure sensor 51 of the pressure monitoring device 5 is arranged at the impeller inlet 24 of the test pump body 2, and the pressure of the fluid is acquired through the pressure sensor 51 and recorded in the measuring instrument 52; the multistage impeller shaft 1 is driven to a preset rotating speed, the pressure of fluid in the impeller inlet 24 is obtained in real time through the pressure sensor 51, and in the process of controlling the induced pressurizing assembly 4 and the flow control device 3 to gradually reduce the auxiliary pressure of the inlet 22 of the test pump body 2, when the measured value obtained by the pressure sensor 51 reaches the pressure critical value of cavitation onset, the current test data is recorded through the measuring instrument 52.
In the description of the embodiment of the application, the performance of the cavitation prevention structure on the impeller is verified by the improved high-lift cryogenic pump cavitation prevention impeller through the performance verification device, the impeller 12 comprises a rear cover 121 and a front cover 122, an impeller inlet is arranged in the middle of the front cover 122, a vane group 124 is arranged between the rear cover 121 and the front cover 122, part of the vane group 124 is connected with a hub 123, and fluid enters through the impeller inlet and passes through the hub 123 and is then pressurized and conveyed to a rear cavity of the impeller 12 by the vane group 124; the rear cover 121 is provided with a plurality of first balance holes 125, and the hub 123 is provided with a plurality of second balance holes 126.
Referring to fig. 7, the diameter of the impeller inlet on the front cover 122 is D1, the vane set 124 includes a first vane 1241 and a second vane 1242, the first vane 1241 extends and is connected to the hub 123, the second vane 1242 has the same extending track as the first vane 1241, and the diameter of a circle formed by the extended end positions of the plurality of second vanes 1242 is greater than D1; the first balance holes 125 are located on the extension line 1250 of the second vane 1242, and a circle formed by a plurality of the first balance holes 125 has a diameter D2, wherein D2> D1.
The arrangement of the balance holes in the impeller 12 reduces disturbance to the main flow at the impeller inlet, the position of the first balance hole 125 is shielded by the front cover 122, direct convergence of the main flow by the fluid passing through the first balance hole 125 is avoided, and it is confirmed that the arrangement of the first balance hole 125 on the extension line 1250 of the second vane 1242 can reduce disturbance to the main flow, specifically, as the diameter of a circle formed by a plurality of the first balance holes 125 is equal to that of the impeller inlet on the front cover 122, the position of the first balance hole 125 is located near the impeller inlet and at a deeper inner position, so that the main flow is converged with the fluid passing through the first balance hole 125 after the flow direction entering the impeller inlet is turned from the radial direction, and the flow direction included angle is reduced when the fluid is converged.
Referring to fig. 8, the hub 123 is provided with the same number of bosses 1231 as the second blades 1242, and the extension lines 1250 of the second blades 1242 extend to the bosses 1231; the boss 1231 is provided with a second balance hole 126, the second balance hole 126 includes an axial section 1261 and a radial section 1262, the axial section 1261 communicates with a rear cavity of the impeller 12, the radial section 1262 communicates with an impeller inlet of the impeller 12, and an outlet of the radial section 1262 faces a radial direction of the impeller 12, so as to reduce disturbance of a main flow by fluid entering the impeller inlet through the second balance hole 126.
In some embodiments of the present invention, the verification of the anti-cavitation impeller and the performance verification device results in that the second blades 1242 are set to be shorter in size and not connected with the hub 123, so that the trafficability of the impeller 12 can be better improved to prevent cavitation, and meanwhile, the extension line 1250 of the second blades 1242 is extended to the boss 1231, so that the disturbance of the main stream of the impeller 12 by the second balance holes 126 provided on the boss 1231 and the first balance holes 125 provided on the extension line 1250 can be reduced, so that the anti-cavitation performance of the impeller 12 is further improved.
The second balance hole 126 is arranged in the hub 123 of the impeller 12, and the radial segment 1262 of the second balance hole 126 enables the fluid flowing out of the second balance hole 126 to be converged into the main flow in the same direction, so that disturbance of the second balance hole 126 to the main flow at the impeller inlet is avoided, and when the fluid flows from the impeller inlet to the surface of the hub 123, the radial segment 1262 adjusts the flow direction of the fluid passing through the balance hole to be similar to the flow direction of the main flow in the area, reverse convergence of the fluid and the main flow in the balance hole is avoided, and disturbance to the main flow is reduced so as to prevent cavitation.
The invention relates to an improved cavitation prevention impeller performance verification process of a high-lift low-temperature pump, which comprises the following steps:
Firstly, controlling an impeller motor 7 to drive a multistage impeller shaft 1 to rotate at a preset rotating speed, wherein the preset rotating speed corresponds to the design power of a high-lift cryogenic pump; secondly, the inducer motor 8 is started to drive the inducer pressurizing assembly 4 to apply a preset auxiliary pressure to the fluid; finally, the flow control device 3 is controlled to gradually reduce the auxiliary pressure output to the inlet 22 of the test pump body 2 through the induction pressurizing assembly 4, and when the measured value obtained by the pressure sensor 51 of the pressure monitoring device 5 reaches the pressure critical value of cavitation onset, the current test data is recorded through the measuring instrument 52; changing the impeller 12 with different structures, specifically changing the apertures of the first balance hole 125, the second balance hole 126 and the position of the first balance hole 125, repeating the above steps and recording the test data again.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (9)
1. The utility model provides a high-lift cryogenic pump cavitation prevention impeller performance verifying attachment, includes induction pressurization subassembly (4) and flow control device (3) to multistage impeller shaft (1) front end pressurization to and measure pressure monitoring devices (5) of multistage impeller shaft (1) front end pressure, its characterized in that:
the multistage impeller shaft (1) is rotatably supported in the test pump body (2) and is in transmission connection with the impeller motor (7) through the first coupler (6), and the multistage impeller shaft (1) is driven to rotate through the impeller motor (7) and reaches a preset rotating speed to match the rated power of the high-lift low-temperature pump;
The induction pressurizing assembly (4) is connected with the test pump body (2) through a flow control device (3), and the flow control device (3) can control the flow of fluid conveyed from the induction pressurizing assembly (4) to the test pump body (2) so as to control the pressure of the front end of the multistage impeller shaft (1) in the test pump body (2);
The pressure monitoring device (5) is arranged in the test pump body (2) and is positioned near the front end of the multistage impeller shaft (1) so as to acquire the pressure at the impeller inlet of the multistage impeller shaft (1), the multistage impeller shaft (1) is accelerated to a preset rotating speed, and under the premise that the pressure acquired by the pressure monitoring device (5) is not lower than a cavitation-primary pressure critical value, an external auxiliary pressure as low as possible is provided for the front end of the multistage impeller shaft (1) through the induction pressurizing assembly (4) and the flow control device (3) so as to verify the cavitation resistance of the multistage impeller shaft (1);
The pressure sensor (51) of the pressure monitoring device (5) is arranged at the impeller inlet (24) of the test pump body (2), and the pressure of the fluid is acquired through the pressure sensor (51) and recorded in the measuring instrument (52);
The multistage impeller shaft (1) is driven to a preset rotating speed, the pressure of fluid in an impeller inlet (24) is obtained in real time through a pressure sensor (51), and current test data are recorded through a measuring instrument (52) when a measured value obtained by the pressure sensor (51) reaches a pressure critical value of cavitation onset in the process of controlling an induction pressurizing assembly (4) and a flow control device (3) to gradually reduce auxiliary pressure of the inlet (22) of a test pump body (2).
2. The high-lift cryopump anti-cavitation impeller performance verification device of claim 1, wherein:
The induction pressurizing assembly (4) comprises a supporting shell (41), two ends of an induction wheel shaft (45) are rotatably supported in the supporting shell (41) through sealing bearings (42), and a low-pressure port (43) and a high-pressure port (44) which are perpendicular to the induction wheel shaft (45) are respectively arranged at two ends of the supporting shell (41);
the spiral inducer (46) is arranged on the inducer shaft (45), the inducer motor (8) is in transmission connection with the inducer shaft (45) through the second coupler (9), and the inducer motor (8) drives the spiral inducer (46) to rotate so as to pressurize fluid entering the low-pressure port (43) and flow the fluid from the high-pressure port (44) to the flow control device (3).
3. The high-lift cryopump anti-cavitation impeller performance verification device of claim 2, wherein:
the flow control device (3) comprises a support valve body (31), a valve rod driving part (32), a valve rod control part (33), a rotary valve core (34), a first connecting flange (35) and a second connecting flange (36);
The support valve body (31) is connected with a high-pressure port (44) of the induced pressurizing assembly (4) through a first connecting flange (35), and the support valve body (31) is connected with an inlet (22) of the test pump body (2) through a second connecting flange (36);
The rotary valve core (34) is rotatably arranged in the spherical cavity in the supporting valve body (31), the rotary valve core (34) is connected with the valve rod driving part (32) through a valve rod, and the valve rod control part (33) controls the valve rod driving part (32) to drive the rotary valve core (34) to rotate so as to control the pressure of fluid flowing from the induced pressurizing assembly (4) to the test pump body (2).
4. The high-lift cryopump anti-cavitation impeller performance verification device of claim 3, wherein:
The rotary valve core (34) comprises a spherical shell (341), a first V-shaped opening (342), a second V-shaped opening (343), a rotary supporting end (344) and a valve rod connecting end (345);
One end of the spherical shell (341) is connected with the valve rod through a valve rod connecting end (345), and the other end of the spherical shell (341) is supported in a spherical cavity of the supporting valve body (31) through a rotary supporting end (344);
The two opposite sides of the spherical shell (341) are respectively provided with a first V-shaped opening (342) and a second V-shaped opening (343), and the tip directions of the first V-shaped opening (342) and the second V-shaped opening (343) are consistent with the rotation direction of the spherical shell (341).
5. The high-lift cryopump anti-cavitation impeller performance verification device of claim 4, wherein:
The multistage impeller shaft (1) comprises a driving shaft (11), impellers (12), an adjusting sleeve (13) and a balance disc (14), wherein two ends of the driving shaft (11) are rotatably arranged in the test pump body (2) through sealing bearings, the driving shaft (11) is in transmission connection with an impeller motor (7) through a first coupling (6), the driving shaft (11) is sleeved with multistage impellers (12), the final-stage impellers (12) are abutted to the adjusting sleeve (13), and the balance disc (14) is arranged on the other side of the adjusting sleeve (13);
An inlet (22) and an outlet (23) are arranged on a supporting shell (21) of the test pump body (2), and fluid enters the test pump body (2) through the inlet (22) and then enters the first-stage impeller (12) through an impeller inlet (24) and is pressurized.
6. An improved cavitation prevention impeller for a high-lift cryogenic pump, which verifies the performance of the cavitation prevention structure on the impeller by the performance verification device according to any one of claims 1-5, and is characterized in that:
The impeller (12) comprises a rear cover (121) and a front cover (122), an impeller inlet is formed in the middle of the front cover (122), a blade group (124) is arranged between the rear cover (121) and the front cover (122), part of the blade group (124) is connected with a hub (123), and fluid enters through the impeller inlet, passes through the hub (123) and is pressurized and conveyed to a rear cavity of the impeller (12) by the blade group (124);
a plurality of first balance holes (125) are formed in the rear cover (121), and a plurality of second balance holes (126) are formed in the hub (123).
7. The improved high-lift cryopump cavitation prevention impeller of claim 6, wherein:
The impeller inlet on the front cover (122) has a diameter of The blade set (124) comprises a first blade (1241) and a second blade (1242), the first blade (1241) extends and is connected to the hub (123), the second blade (1242) has the same extending track as the first blade (1241), and the diameter of a circle formed by the extending termination positions of a plurality of the second blades (1242) is larger than/>；
The first balance holes (125) are positioned on the extension line (1250) of the second blade (1242), the diameter of the circle formed by a plurality of the first balance holes (125) isWherein/>> />。
8. The improved high-lift cryopump cavitation prevention impeller of claim 7, wherein:
The hub (123) is provided with the same number of bosses (1231) as the second blades (1242), and the extension lines (1250) of the second blades (1242) extend to the bosses (1231);
Be provided with second balance hole (126) on boss (1231), second balance hole (126) include axial section (1261) and radial section (1262), the rear chamber of axial section (1261) intercommunication impeller (12), radial section (1262) intercommunication impeller entry of impeller (12), the export of radial section (1262) is towards the radial direction of impeller (12), in order to reduce through second balance hole (126) get into the fluid of impeller entry is to the disturbance of mainstream.
9. An improved performance verification method for an anti-cavitation impeller of a high-lift cryogenic pump, which is characterized by comprising the following steps of:
Step a, controlling an impeller motor (7) to drive a multistage impeller shaft (1) to rotate at a preset rotating speed, wherein the preset rotating speed corresponds to the design power of a high-lift cryogenic pump;
Step b, starting an inducer motor (8) to drive an inducer pressurizing assembly (4) to apply a preset auxiliary pressure to the fluid;
step c, controlling the flow control device (3) to gradually reduce the auxiliary pressure output to the inlet (22) of the test pump body (2) through the induction pressurizing assembly (4), and recording current test data through the measuring instrument (52) when the measured value obtained by the pressure sensor (51) of the pressure monitoring device (5) reaches the pressure critical value of cavitation onset;
And d, replacing impellers (12) with different structures, specifically changing the apertures of the first balance holes (125) and the second balance holes (126) and the positions of the first balance holes (125), and repeating the steps a to c.
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| CN105736116B (en) * | 2016-04-18 | 2018-06-26 | 江苏大学 | A kind of intelligent controllable water pump of anti-cavitation |
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| JP6947152B2 (en) * | 2018-12-07 | 2021-10-13 | 横河電機株式会社 | Detection device, detection method, and detection program |
| CN213205984U (en) * | 2020-06-30 | 2021-05-14 | 中国电建集团郑州泵业有限公司 | High-efficiency economical multistage centrifugal pump set |
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| CN113958506A (en) * | 2021-07-31 | 2022-01-21 | 高涛 | Centrifugal pump |
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| CN103758764A (en) * | 2013-12-26 | 2014-04-30 | 潘红兵 | Method for serially connecting a plurality of water pumps by using hoses |
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