CN115247657A - Self-circulation jet anti-cavitation structure and centrifugal pump with anti-cavitation structure - Google Patents
Self-circulation jet anti-cavitation structure and centrifugal pump with anti-cavitation structure Download PDFInfo
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- CN115247657A CN115247657A CN202111608524.5A CN202111608524A CN115247657A CN 115247657 A CN115247657 A CN 115247657A CN 202111608524 A CN202111608524 A CN 202111608524A CN 115247657 A CN115247657 A CN 115247657A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/18—Rotors
- F04D29/22—Rotors specially for centrifugal pumps
- F04D29/2238—Special flow patterns
- F04D29/2255—Special flow patterns flow-channels with a special cross-section contour, e.g. ejecting, throttling or diffusing effect
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/18—Rotors
- F04D29/22—Rotors specially for centrifugal pumps
- F04D29/2261—Rotors specially for centrifugal pumps with special measures
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
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- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
The invention provides a self-circulation jet anti-cavitation structure and a centrifugal pump with the same, belongs to the technical field of centrifugal pumps, and aims to solve the problem that the existing centrifugal pump is poor in anti-cavitation performance. The self-circulation cavity structure consisting of a liquid storage tank and a flow through pipe is arranged on the outer side of the rim of the impeller, the flow through pipe, the liquid storage tank and the jet holes enable the outer side of the rim of the impeller to form a communicated high-pressure loop system, communication under different working conditions is realized by controlling opening and closing of a first jet hole and a second jet hole, the flow of an outlet runner of the impeller flows into the liquid storage tank through a communicating pipe and then is injected into an inlet runner of the impeller through the jet holes at different positions, so that the effect of applying jet flow to a flow field is generated, compensation on a flow separation area of the front edge of the blade under different working conditions can be realized, self-regulation is realized, the problem of cavitation of the centrifugal pump caused by operation under different working conditions is effectively solved, and the operation stability of the centrifugal pump is improved; the jet structure does not need to be added, the structure is simple, and the realization is easy.
Description
Technical Field
The invention belongs to the technical field of centrifugal pumps, and relates to a self-circulation jet anti-cavitation structure and a centrifugal pump with the same.
Background
The centrifugal pump mainly comprises a centrifugal impeller and a volute, wherein the centrifugal impeller is a main core component of the centrifugal pump, an outlet of the impeller is connected with the volute, and a gap exists between the impeller and the volute. When the centrifugal pump works, the rotating impeller applies work to the liquid flow, so that the speed, the pressure and the like of the liquid flow are increased, and high lift is obtained. When the operating flow of the centrifugal pump is smaller than the design flow, a positive attack angle appears at the inlet of the impeller, and the pressure of the suction surface of the blade is reduced to the local vaporization pressure to cause cavitation; when the operation flow is larger than the design flow, a negative attack angle appears at the inlet of the impeller, and cavitation can also occur when the pressure of the pressure surface of the blade is reduced to the local vaporization pressure; however, no matter under the working conditions of large flow or small flow, as long as the cavitation phenomenon occurs in the centrifugal pump, the operation efficiency of the centrifugal pump is influenced, and vibration and noise are caused; when the cavitation is serious, the overflowing part of the centrifugal pump is damaged, and the running stability and reliability of the centrifugal pump are influenced.
The inducer is additionally arranged in front of the centrifugal impeller, which is the most common method for solving the problem of centrifugal pump cavitation, and the problem of centrifugal pump cavitation is solved by improving the inlet pressure of the impeller. However, this approach not only increases the size of the centrifugal pump, but also requires consideration of the interaction of the inducer and the centrifugal impeller. In addition, the inducer itself also needs to have strong anti-cavitation capability to ensure the stable operation of the whole centrifugal pump.
Therefore, a self-circulation jet structure which has a simple structure and can effectively solve the problem of cavitation of the centrifugal pump caused by the operation condition on the premise of not increasing additional flow components is needed to be designed.
Disclosure of Invention
The invention aims to solve the problems in the prior art, provides a self-circulation jet anti-cavitation structure and a centrifugal pump with the anti-cavitation structure, and aims to solve the technical problems that: how to improve the anti-cavitation performance of the centrifugal pump on the premise of not adding extra flow parts. This anti-cavitation structure of self-loopa efflux can improve blade pressure face pressure when large-traffic, improves blade suction face pressure when little flow to effectively solve the centrifugal pump because the cavitation problem that the operation of partial operating mode caused, improve the operating stability of centrifugal pump.
The purpose of the invention can be realized by the following technical scheme:
a self-circulation jet anti-cavitation structure comprises an impeller, wherein the impeller comprises an impeller rim, a rear cover plate, a front cover plate, blades and a water level monitoring connecting seat, the water level monitoring connecting seat and the front cover plate are respectively arranged at two ends of the impeller rim, the rear cover plate is positioned on the outer side of the front cover plate, a hub is arranged in the middle of the impeller, the middle of each blade is connected with the hub, each blade is positioned between the rear cover plate and the front cover plate, an impeller outlet flow channel is arranged between the rear cover plate and the front cover plate, and an impeller inlet flow channel is arranged on one side of the impeller, which is positioned on the water level monitoring connecting seat; a plurality of liquid storage tanks and jet pipes are arranged outside the rim of the impeller, the upper part of each liquid storage tank is communicated with an impeller outlet runner through a communicating pipe, a plurality of jet holes are arranged in an impeller inlet runner, and the liquid storage tanks are communicated with the jet holes through the jet pipes; the two jet holes are in a group and are sequentially named as a first jet hole and a second jet hole according to the flow direction of liquid flow, the axial distribution areas of the first jet hole and the second jet hole in the same group are positioned near the front edge of the blade, the circumferential distribution of the first jet hole and the second jet hole is arranged according to the jet direction, wherein the first jet hole sprays towards the suction surface of the blade, and the second jet hole sprays towards the front edge and the pressure surface of the blade; the liquid storage tank is internally provided with a shielding slider in a sliding manner, the switches of the first jet hole and the second jet hole are controlled by the shielding slider, the shielding slider is provided with a through hole corresponding to the jet hole, a water level monitoring cavity is formed in the water level monitoring connecting seat, a plurality of water level monitoring floating sliders are arranged in the water level monitoring cavity in a sliding manner, the water level monitoring floating sliders are connected with the shielding sliders through connecting rods, when the working condition of small flow is adopted, the floating sliders are kept in a low liquid level state, the shielding sliders are used for enabling the first jet hole to be opened and the second jet hole to be closed, when the working condition of large flow is adopted, the floating sliders are kept in a high liquid level state, the water level monitoring floating sliders are driven to shield the sliders to move, and the first jet hole is closed and the second jet hole is opened.
The working principle of the invention is as follows: the self-circulation cavity structure consisting of a liquid storage tank and a flow through pipe is arranged on the outer side of the rim of the impeller, the flow through pipe, the liquid storage tank and the jet holes enable the outer side of the rim of the impeller to form a communicated high-pressure loop system, a liquid inlet of the liquid storage tank is communicated with an outlet runner of the impeller through a communicating pipe, a liquid outlet of the liquid storage tank is communicated with the jet holes formed in an inlet runner of the impeller through the jet pipes, two jet holes are in a group, the jet directions of the first jet hole and the second jet hole are different, the first jet hole is jetted towards a suction surface of the blade, the second jet hole is jetted towards a front edge and a pressure surface of the blade, the communication under different working conditions is realized by controlling the opening and closing of the first jet hole and the second jet hole, the flow of the outlet runner of the impeller flows into the liquid storage tank through the communicating pipe and then is jetted into the inlet runner of the impeller through the jet holes at different positions, so that the jet effect of applying jet flow to the flow field is generated, certain pressure is generated on different surfaces of the blade according to different flow working conditions, the self-regulating is realized, and the anti-cavitation performance is improved; under different flow operating modes, the position of the water level monitoring floating slide block at the position of the impeller inlet flow channel is different, the displacement of the water level monitoring floating slide block drives the movement of the shielding slide block, the position of the shielding slide block in the liquid storage tank can realize the on-off of the jet holes at different positions, and therefore the on-off of the first jet hole and the second jet hole can be automatically controlled, and different jet effects are formed.
The jet holes are sequentially arranged along the axial direction, the second jet holes are located on the outer sides of the first jet holes, in different jet hole groups, the axial positions of all the first jet holes are the same, the axial positions of all the second jet holes are the same, the second jet holes are guaranteed to be sprayed towards the head part and the working face of the blade, and the first jet holes are sprayed towards the suction surface of the blade.
The jet hole groups are uniformly distributed in the circumferential direction, and Kong Zushu is an integral multiple of the number of blades; preferably, the number of blades is six and the number of sets of jet holes is twelve; by adopting the structure, the damage to the circumferential uniformity of the flow field of the centrifugal pump caused by the circumferential nonuniformity of the jet flow can be avoided.
A pump shaft mounting hole is formed in the middle of the hub, a plurality of through flow holes connected with the through flow pipes are formed in the front cover plate, and the through flow holes are uniformly distributed in the circumferential direction; part of water in the impeller outlet flow channel flows into the liquid storage tank through the draft tube and is injected into the impeller inlet flow channel through the jet hole to form a self-circulation high-pressure jet loop.
A plurality of water level monitoring cavitys have been seted up to the inside of water level monitoring connecting seat, and the quantity of water level monitoring cavity corresponds the setting with the quantity of liquid reserve tank, and the outside of water level monitoring connecting seat is provided with the flange, and the unsteady slider of water level monitoring slides and sets up in the water level monitoring cavity, and the spacing groove has been seted up to one side of water level monitoring cavity, and the spread groove is worn out to one side of the unsteady slider of water level monitoring and the one end of connecting rod is articulated, and the other end of connecting rod is articulated with the slider that shelters from.
In order to realize the automatic control of the working states of the first jet hole and the second jet hole, an adjustable shielding slide block is arranged in the liquid storage tank; under the working condition of small flow, the shielding slide block is controlled to enable the first jet hole to work and the second jet hole to be blocked; and under the working condition of large flow, the shielding slide block is controlled to enable the second jet hole to work and the first jet hole to be blocked.
The shielding sliding block adopts any structure as long as the functions can be realized.
The shielding sliding block is of a sliding block structure connected with the liquid storage tank in a sliding mode, and the length of the shielding sliding block is matched with the circumferential positions of the width of the liquid storage tank, the first jet hole, the second jet hole and the water level monitoring cavity in a mutual mode to be designed. The aperture of the through hole formed in the shielding sliding block is slightly larger than that of the first jet hole. The length of the left side of the shielding sliding block hole is equal to the distance between the first jet hole and the wall surface of the left side of the liquid storage tank, the through hole is communicated with the first jet hole and the second jet hole is shielded under the working condition of small flow, and the through hole formed in the shielding sliding block is communicated with the second jet hole and the first jet hole is shielded under the working condition of large flow.
Each group of jet holes are independently arranged, and the liquid storage tanks above different jet hole groups are not communicated with each other.
The orientation of the first jet hole and the second jet hole is selected according to the range size of the flow separation area on the pressure surface side and the suction surface side of the blade leading edge, so that the impact flow separation center position is optimal.
The opening size of the jet hole is designed to take two working conditions of large flow and small flow into consideration. Preferably, the jet hole diameter ranges from 0.4mm to 1.0mm. Under the working condition of small flow, the total flow of the jet holes is controlled to be 4% -8% of the total flow of the impeller so as to reduce the influence of the jet self-circulation loop on the performance of the centrifugal pump, and in order to form high-speed jet, the diameter of an opening of the first jet hole is required to be smaller. Under the working condition of large flow, the total jet flow can be controlled to be 6% -10% of the total flow, and in order to form stable jet flow, the diameter of the opening of the second jet hole is required to be increased properly. In addition, the opening diameters of the first jet hole and the second jet hole are determined according to the number of the circumferential jet hole groups.
The utility model provides a centrifugal pump with anti cavitation structure, adopts above-mentioned self-loopa efflux anti cavitation structure in centrifugal pump impeller, realizes compensating the blade leading edge flow separation region under the different operating mode conditions, effectively solves the centrifugal pump because the cavitation problem that the operation of partial operating mode caused improves the operating stability of centrifugal pump.
Compared with the prior art, the self-circulation jet anti-cavitation structure and the centrifugal pump with the anti-cavitation structure have the following advantages:
1. the self-circulation cavity structure consisting of a liquid storage tank and a flow through pipe is arranged on the outer side of the rim of the impeller, the flow through pipe, the liquid storage tank and the jet holes enable the outer side of the rim of the impeller to form a communicated high-pressure loop system, a liquid inlet of the liquid storage tank is communicated with an outlet runner of the impeller through a communicating pipe, a liquid outlet of the liquid storage tank is communicated with the jet holes formed in an inlet runner of the impeller through the jet pipes, two jet holes are in a group, the jet directions of the first jet hole and the second jet hole are different, the first jet hole is jetted towards the suction surface of the blade, and the second jet hole is jetted towards the front edge and the pressure surface of the blade; the first jet hole and the second jet hole are controlled to be opened and closed, communication under different working conditions is achieved, the flow of the impeller outlet flow channel flows into the liquid storage tank through the communicating pipe, and then the flow is injected into the impeller inlet flow channel through the jet holes at different positions, so that the effect of applying jet flow to the flow field is achieved, certain pressure is generated on different surfaces of the impeller according to different flow working conditions, self-adjustment is achieved, and anti-cavitation performance is improved. The flow separation area of the front edge of the blade can be compensated under different working conditions, the pressure of the pressure surface of the blade can be increased under the condition of large flow, and the pressure of the suction surface of the blade can be increased under the condition of small flow, so that the cavitation problem of the centrifugal pump caused by the operation under the deviated working condition is effectively solved, and the operation stability of the centrifugal pump is improved; and an additional jet structure is not needed, the structure is simple, and the realization is easy.
2. The shielding relation can meet the working conditions of large flow and small flow through the matching of the arrangement of the positions of the first jet hole and the second jet hole. The liquid storage tank is internally provided with a shielding slider in a sliding manner, the switches of the first jet hole and the second jet hole are controlled by the shielding slider, the shielding slider is provided with a through hole corresponding to the jet hole, a water level monitoring cavity is formed in the water level monitoring connecting seat, a plurality of water level monitoring floating sliders are arranged in the water level monitoring cavity in a sliding manner, the water level monitoring floating sliders are connected with the shielding sliders through connecting rods, when the working condition of small flow is adopted, the floating sliders are kept in a low liquid level state, the shielding sliders are used for enabling the first jet hole to be opened and the second jet hole to be closed, when the working condition of large flow is adopted, the floating sliders are kept in a high liquid level state, the water level monitoring floating sliders are driven to shield the sliders to move, and the first jet hole is closed and the second jet hole is opened. Under different flow operating modes, the position of the water level monitoring floating slide block at the position of the impeller inlet flow channel is different, the displacement of the water level monitoring floating slide block drives the movement of the shielding slide block, the position of the shielding slide block in the liquid storage tank can realize the on-off of the jet holes at different positions, and therefore the on-off of the first jet hole and the second jet hole can be automatically controlled, and different jet effects are formed.
Drawings
FIG. 1 is a schematic front axle side construction of the present invention;
FIG. 2 is a schematic rear axle side construction of the present invention;
FIG. 3 is a schematic front view of the present invention;
FIG. 4 is a rear view of the present invention;
FIG. 5 isbase:Sub>A schematic cross-sectional view of section A-A of FIG. 4;
FIG. 6 is a side view schematic of the present invention;
FIG. 7 is a schematic cross-sectional view of section B-B of FIG. 6;
FIG. 8 is a schematic perspective view of FIG. 7;
FIG. 9 is a schematic view of the operation of the jet hole under low flow conditions;
FIG. 10 is a schematic view of the operating state of the jet hole under a large flow condition;
in the figure: 1-impeller rim, 2-back cover plate, 3-front cover plate, 4-blade, 5-liquid storage tank, 6-jet pipe, 7-impeller outlet flow channel, 8-water level monitoring connecting seat, 9-impeller inlet flow channel, 10-water level monitoring floating slide block, 11-first jet hole, 12-second jet hole, 13-hub, 14-flange, 15-connecting rod, 16-jet hole, 17-pump shaft mounting hole, 18-water level monitoring cavity, 19-shading slide block and 20-jet pipe.
Detailed Description
The technical solution of the present patent will be described in further detail with reference to the following embodiments.
Reference will now be made in detail to embodiments of the present patent, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are illustrative only for the purpose of explaining the present patent and are not to be construed as limiting the present patent.
In the description of this patent, it is to be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientations and positional relationships indicated in the figures, which are based on the orientations and positional relationships shown in the figures, and are used for convenience in describing the patent and for simplicity in description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore should not be construed as limiting the patent.
In the description of this patent, it is noted that unless otherwise specifically stated or limited, the terms "mounted," "connected," and "disposed" are to be construed broadly and can include, for example, fixedly connected, disposed, detachably connected, disposed, or integrally connected and disposed. The specific meaning of the above terms in this patent may be understood by those of ordinary skill in the art as appropriate.
Referring to fig. 1-10, the embodiment provides a self-circulation jet anti-cavitation structure, which includes an impeller, the impeller includes an impeller rim 1, a rear cover plate 2, a front cover plate 3, blades 4 and a water level monitoring connecting seat 8, the water level monitoring connecting seat 8 and the front cover plate 3 are respectively disposed at two ends of the impeller rim 1, the rear cover plate 2 is located at the outer side of the front cover plate 3, a hub 13 is disposed in the middle of the impeller, the middle of the blade 4 is connected with the hub 13, the blade 4 is located between the rear cover plate 2 and the front cover plate 3, an impeller outlet flow channel 7 is disposed between the rear cover plate 2 and the front cover plate 3, and an impeller inlet flow channel 9 is disposed at one side of the impeller located at the water level monitoring connecting seat 8; a plurality of liquid storage tanks 5 and jet pipes 6 are arranged outside the impeller rim 1, the upper parts of the liquid storage tanks 5 are communicated with an impeller outlet runner 7 through communicating pipes 6, a plurality of jet holes are arranged in an impeller inlet runner 9, and the liquid storage tanks 5 are communicated with the jet holes through jet pipes 20; the two jet holes are a group and are named as a first jet hole 11 and a second jet hole 12 in sequence according to the flow direction of liquid flow, the axial distribution areas of the first jet hole 11 and the second jet hole 12 in the same group are positioned near the front edge of the blade 4, the circumferential distribution of the first jet hole 11 and the second jet hole 12 is arranged according to the jet direction, wherein the first jet hole 11 is jetted towards the suction surface of the blade, and the second jet hole 12 is jetted towards the front edge and the pressure surface of the blade; the sliding is provided with shelters from slider 19 in the liquid reserve tank 5, the switch of first jet orifice 11 and second jet orifice 12 is through sheltering from slider 19 control, shelter from and be provided with the through-hole corresponding with the jet orifice on the slider 19, water level monitoring cavity 18 has been seted up to the inside of water level monitoring connecting seat 8, it is provided with a plurality of water level monitoring slider 10 that floats to slide in the water level monitoring cavity 18, water level monitoring slider 10 with shelter from slider 19 and pass through connecting rod 15 and be connected, when the low discharge operating mode, slider 10 that floats keeps low liquid level state, shelter from slider 19 and make first jet orifice 11 open and second jet orifice 12 closes, when large-traffic operating mode, slider 10 that floats keeps high liquid level state, water level monitoring slider 10 drives shelters from slider 19 and removes, make first jet orifice 11 close and second jet orifice 12 opens.
The self-circulation cavity structure consisting of a liquid storage tank 5 and a flow through pipe 6 is arranged on the outer side of an impeller rim 1, the flow through pipe 6, the liquid storage tank 5 and the jet holes enable the outer side of the impeller rim 1 to form a communicated high-pressure loop system, a liquid inlet of the liquid storage tank 5 is communicated with an impeller outlet flow passage 7 through a communicating pipe 6, a liquid outlet of the liquid storage tank 5 is communicated with the jet holes formed in an impeller inlet flow passage 9 through a jet pipe 20, the jet holes are in a group, the jet directions of a first jet hole 11 and a second jet hole 12 are different, the first jet hole 11 is jetted towards the suction surface of a blade 4, the second jet hole 12 is jetted towards the front edge and the pressure surface of the blade 4, communication under different working conditions is realized by controlling the opening and closing of the first jet hole 11 and the second jet hole 12, the flow of the impeller outlet flow passage 7 flows into the liquid storage tank 5 through the communicating pipe 6, and then is jetted into the impeller inlet flow passage 9 through the jet holes at different positions, so as to generate the effect of jet flow to exert jet flow to the flow field, and generate certain pressure on different working conditions of the blade according to different flow, thereby realizing self-regulation and improving the cavitation resistance performance; under different flow operating modes, the position of the water level monitoring floating slider 10 at the position of the impeller inlet channel 9 is different, the displacement of the water level monitoring floating slider 10 drives the movement of the shielding slider 19, the position of the shielding slider 19 in the liquid storage tank 5 can realize the on-off of the jet holes at different positions, and therefore the on-off of the first jet hole 11 and the second jet hole 12 can be automatically controlled to form different jet effects.
The jet holes are sequentially arranged along the axial direction, the second jet holes 12 are positioned on the outer sides of the first jet holes 11, the axial positions of all the first jet holes 11 are the same in different jet hole groups, the axial positions of all the second jet holes 12 are the same, the second jet holes 12 are guaranteed to be sprayed towards the head and the working face of the blade 4, and the first jet holes 11 are sprayed towards the suction surface of the blade 4.
In order to avoid the damage of the circumferential uniformity of the flow field of the centrifugal pump caused by the circumferential nonuniformity of the jet flow, the jet flow hole groups are uniformly distributed in the circumferential direction, and Kong Zushu is integral multiple of the number of blades. Preferably, in this embodiment, the number of blades is six and the number of jet hole groups is twelve. If the circumferential non-uniform control of the flow field is to be realized, a circumferential non-uniform arrangement mode of the jet hole groups can also be adopted.
A plurality of water level monitoring cavities 18 have been seted up to water level monitoring connecting seat 8's inside, the quantity of water level monitoring cavity 18 corresponds the setting with the quantity of liquid reserve tank 5, in this embodiment, the quantity of water level monitoring cavity 18 is twelve, the outside of water level monitoring connecting seat 8 is provided with flange 14, water level monitoring unsteady slider 10 slides and sets up in water level monitoring cavity 18, the spacing groove has been seted up to one side of water level monitoring cavity 18, the spread groove is worn out to one side of water level monitoring unsteady slider 10 and the one end of connecting rod 15 is articulated, the other end of connecting rod 15 is articulated with sheltering from slider 19.
In order to realize the automatic control of the working states of the first jet hole 11 and the second jet hole 12, an adjustable shielding slide block 19 is arranged in the liquid storage tank 5; under the working condition of small flow, the shielding slide block 19 is controlled to enable the first jet hole 11 to work and the second jet hole 12 to be blocked; under the working condition of large flow, the shielding slide block 19 is controlled to enable the second jet hole 12 to work and the first jet hole 11 to be blocked.
The shielding slider 19 may have any structure as long as the above function is realized. Preferably, in this case, the shielding slider 19 is a slider structure slidably connected to the liquid storage tank 5, and the length of the shielding slider 19 is designed to be matched with the width of the liquid storage tank 5, the circumferential positions of the first jet hole 11, the second jet hole 12 and the water level monitoring cavity 18. The aperture of the through hole formed in the shielding sliding block 19 is slightly larger than that of the first jet hole 11. The left side length of sheltering from 19 trompils of slider equals the distance between first jet orifice 11 and the 5 left side walls of liquid reserve tank, when the low discharge operating mode, guarantees through-hole and first jet orifice 11 intercommunication, shelters from second jet orifice 12, and when large-traffic operating mode, shelters from the through-hole and the second jet orifice 12 intercommunication of seting up on the slider 19, shelters from first jet orifice 11.
Each group of jet holes are independently arranged, and the liquid storage tanks 5 above different jet hole groups are not communicated with each other.
As shown in FIG. 9, when the centrifugal pump operates in a low flow condition, a positive attack angle is generated at the inlet of the vane 4, liquid flow impacts on the pressure surface of the vane, the pressure of the suction surface of the vane is reduced, flow separation occurs, and when the pressure of the low pressure area of the suction surface of the vane is reduced to the vaporization pressure of a medium, cavitation can be generated. Under the working condition of small flow, because the flow in the impeller inlet flow passage 9 is small, the water level monitoring cavity 18 is in a low liquid level state, the water level monitoring floating slide block 10 descends along with the water level, the connecting rod 9 drives the shielding slide block 19 to move left, the through hole on the shielding slide block 19 is communicated with the first jet hole 11, the second jet hole 12 is in a closed state, the high-pressure liquid flow sprayed to the suction surface of the blade from the first jet hole 11 compensates the low pressure of the suction surface of the blade 4, the pressure of a low-pressure area is increased to be higher than the vaporization pressure of the liquid, and therefore cavitation of the suction surface of the blade 4 is relieved.
As shown in fig. 10, when the centrifugal pump operates in a large flow working condition, a negative attack angle is generated at the inlet of the blade 4, liquid flow impacts the suction surface of the blade 4, pressure of the pressure surface of the blade 4 is reduced, flow separation occurs, and when the pressure of the pressure surface of the blade 4 is reduced to the vaporization pressure of a medium, cavitation occurs. Under the working condition of large flow, because the flow in the impeller inlet channel 9 is large, the liquid level in the water level monitoring cavity 18 rises, the water level monitoring floating slide block 10 moves upwards under the action of buoyancy, the water level monitoring floating slide block 10 drives the connecting rod 15 to move upwards, the connecting rod 15 drives the shielding slide block 19 to move rightwards, the through hole on the shielding slide block 19 is communicated with the second jet hole 12, the first jet hole 11 is in a closed state, and high-pressure fluid sprayed to the head part of the blade 4 and the pressure surface of the blade from the second jet hole 12 compensates the low pressure at the position, so that the cavitation of the pressure surface of the blade is relieved.
The selection of the orientation of the first jet hole 11 and the second jet hole 12 depends on the extent of the flow separation region on the pressure surface side and the suction surface side of the leading edge of the blade 4 to optimize the impingement flow separation center position.
The opening size of the jet hole is designed to take two working conditions of large flow and small flow into consideration. Preferably, the jet hole diameter ranges from 0.4mm to 1.0mm. Under the working condition of small flow, the total flow of the jet holes is controlled to be 4% -8% of the total flow of the impeller so as to reduce the influence of the jet self-circulation loop on the performance of the centrifugal pump, and in order to form high-speed jet, the diameter of an opening of the first jet hole 11 is required to be smaller. Under the working condition of large flow, the total jet flow of the jet holes is controlled to be 6% -10% of the total flow of the impeller, and in order to form stable jet flow, the opening diameter of the second jet hole 12 needs to be increased properly. Further, the opening diameters of the first jet hole 11 and the second jet hole 12 are determined in accordance with the number of circumferential jet hole groups. In the embodiment, the number of the blades 4 is six, the number of the circumferential hole groups is two times of the number of the blades, and the opening diameter of the first jet hole 11 is set to be 0.4mm-0.8mm under a low-flow working condition; under the working condition of large flow, the diameter of the opening of the second jet hole 12 is set to be 0.6mm-1.0mm.
A centrifugal pump with anti-cavitation structure, adopt the above-mentioned anti-cavitation structure of self-circulating jet flow in the centrifugal pump, in this centrifugal pump, set up the self-circulating cavity structure composed of liquid storage tank 5 and draught tube 6 outside the wheel rim 1, draught tube 6, liquid storage tank 5 and jet hole make the wheel rim 1 outside form the high-pressure loop system communicated, the inlet of the liquid storage tank 5 is linked together with outlet runner 7 of the impeller through the communicating pipe 6, the liquid outlet of the liquid storage tank 5 is linked together through the jet pipe 20 with the jet hole set up in the inlet runner 9 of the impeller, two jet holes are a set of, the jet direction of the first jet hole 11 and second jet hole 12 is different, the first jet hole 11 is sprayed towards the suction surface of the blade 4, the second jet hole 12 is sprayed towards the leading edge and pressure surface of the blade 4; the communication under different working conditions is realized by controlling the opening and closing of the first jet orifice 11 and the second jet orifice 12, the flow of the impeller outlet flow passage 7 flows into the liquid storage tank 5 through the communicating pipe 6, and then is injected into the impeller inlet flow passage 9 through the jet orifices at different positions, so that the effect of applying jet flow to a flow field is generated, certain pressure is generated on different surfaces of the impeller according to different flow working conditions, the self-regulation is realized, and the anti-cavitation performance is improved. Under the working condition of small flow, because the flow in the impeller inlet flow passage 9 is small, the water level monitoring cavity 18 is in a low liquid level state, the water level monitoring floating slide block 10 descends along with the water level, the connecting rod 9 drives the shielding slide block 19 to move left, the through hole on the shielding slide block 19 is communicated with the first jet hole 11, the second jet hole 12 is in a closed state, the high-pressure liquid flow sprayed to the suction surface of the blade from the first jet hole 11 compensates the low pressure of the suction surface of the blade 4, the pressure of a low-pressure area is increased to be higher than the vaporization pressure of the liquid, and therefore cavitation of the suction surface of the blade 4 is relieved. Under the working condition of large flow, because the flow in the impeller inlet channel 9 is large, the liquid level in the water level monitoring cavity 18 rises, the water level monitoring floating slide block 10 moves upwards under the action of buoyancy, the water level monitoring floating slide block 10 drives the connecting rod 15 to move upwards, the connecting rod 15 drives the shielding slide block 19 to move rightwards, the through hole on the shielding slide block 19 is communicated with the second jet hole 12, the first jet hole 11 is in a closed state, the high-pressure fluid sprayed to the head part of the blade 4 and the pressure surface of the blade from the second jet hole 12 compensates the low pressure at the position, and the cavitation of the pressure surface of the blade is relieved. Therefore, the flow separation area of the front edge of the blade is compensated under different working conditions, the pressure of the pressure surface of the blade can be increased under the condition of large flow, and the pressure of the suction surface of the blade can be increased under the condition of small flow, so that the problem of cavitation of the centrifugal pump caused by operation under a deviated working condition is effectively solved, and the operation stability of the centrifugal pump is improved; and an additional jet structure is not needed, the structure is simple, and the realization is easy.
Although the preferred embodiments of the present patent have been described in detail, the present patent is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present patent within the knowledge of those skilled in the art.
Claims (9)
1. A self-circulation jet anti-cavitation structure comprises an impeller and is characterized in that the impeller comprises an impeller wheel rim, a rear cover plate, a front cover plate, blades and a water level monitoring connecting seat, the water level monitoring connecting seat and the front cover plate are respectively arranged at two ends of the impeller wheel rim, the rear cover plate is positioned on the outer side of the front cover plate, a hub is arranged in the middle of the impeller, the middle of each blade is connected with the hub, each blade is positioned between the rear cover plate and the front cover plate, an impeller outlet flow channel is arranged between the rear cover plate and the front cover plate, and an impeller inlet flow channel is arranged on one side of the impeller, which is positioned on the water level monitoring connecting seat; a plurality of liquid storage tanks and jet pipes are arranged outside the rim of the impeller, the upper parts of the liquid storage tanks are communicated with an impeller outlet flow passage through communicating pipes, a plurality of jet holes are arranged in an impeller inlet flow passage, and the liquid storage tanks are communicated with the jet holes through the jet pipes; the two jet holes are in a group and are sequentially named as a first jet hole and a second jet hole according to the flow direction of liquid flow, the axial distribution areas of the first jet hole and the second jet hole in the same group are positioned near the front edge of the blade, the circumferential distribution of the first jet hole and the second jet hole is arranged according to the jet direction, wherein the first jet hole sprays towards the suction surface of the blade, and the second jet hole sprays towards the front edge and the pressure surface of the blade; the liquid storage tank is internally provided with a shielding slider in a sliding manner, the switches of the first jet hole and the second jet hole are controlled by the shielding slider, the shielding slider is provided with a through hole corresponding to the jet hole, a water level monitoring cavity is formed in the water level monitoring connecting seat, a plurality of water level monitoring floating sliders are arranged in the water level monitoring cavity in a sliding manner, the water level monitoring floating sliders are connected with the shielding sliders through connecting rods, when the working condition of small flow is adopted, the floating sliders are kept in a low liquid level state, the shielding sliders are used for enabling the first jet hole to be opened and the second jet hole to be closed, when the working condition of large flow is adopted, the floating sliders are kept in a high liquid level state, the water level monitoring floating sliders are driven to shield the sliders to move, and the first jet hole is closed and the second jet hole is opened.
2. The self-circulation jet anti-cavitation structure according to claim 1, wherein the jet holes are sequentially arranged along the axial direction, the second jet holes are located outside the first jet holes, in different jet hole groups, the axial positions of all the first jet holes are the same, the axial positions of all the second jet holes are the same, each group of jet holes are independently arranged, and the liquid storage tanks above the different jet hole groups are not communicated with each other.
3. The self-circulating jet anti-cavitation structure as claimed in claim 2, wherein the jet hole groups are circumferentially uniformly distributed, and Kong Zushu is an integral multiple of the number of blades.
4. The self-circulating jet anti-cavitation structure as claimed in claim 3, wherein the number of the blades is six and the number of the jet hole groups is twelve.
5. The self-circulation jet anti-cavitation structure as claimed in claim 1, wherein the hub is provided with a pump shaft mounting hole at the middle part, the front cover plate is provided with a plurality of through holes connected with the through flow pipe, and the through holes are circumferentially and uniformly distributed.
6. The self-circulation jet anti-cavitation structure as claimed in claim 3, wherein a plurality of water level monitoring cavities are formed inside the water level monitoring connecting seat, and the number of the water level monitoring cavities is corresponding to the number of the liquid storage tanks; the outside of water level monitoring connecting seat is provided with the flange, and water level monitoring slider that floats slides and sets up in the water level monitoring cavity, and the spacing groove has been seted up to one side of water level monitoring cavity, and the spread groove is worn out to one side of water level monitoring slider that floats and the one end of connecting rod is articulated, and the other end of connecting rod is articulated with sheltering from the slider.
7. The self-circulating jet anti-cavitation structure as claimed in claim 6, wherein the jet hole diameter is in the range of 0.4mm to 1.0mm; under the working condition of small flow, the total flow of the jet holes is controlled to be 4% -8% of the total flow of the impeller, and under the working condition of large flow, the total flow of the jet holes is controlled to be 6% -10% of the total flow of the impeller.
8. The self-circulation jet anti-cavitation structure according to claim 7, wherein the opening diameter of the first jet hole is set to 0.4mm to 0.8mm; the opening diameter of the second jet hole 12 is set to 0.6mm to 1.0mm.
9. A centrifugal pump having an anti-cavitation structure, wherein the self-circulating jet anti-cavitation structure as recited in any one of claims 1 to 8 is provided in an impeller of the centrifugal pump.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116221131A (en) * | 2023-04-10 | 2023-06-06 | 台州科技职业学院 | Adjusting device for improving cavitation resistance of water pump and control method |
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