CN219452498U - Special turbine impeller with splitter blades - Google Patents

Abstract

The utility model discloses a special turbine impeller with a splitter blade, which comprises a main body, wherein the main body is arranged on a main shaft of a centrifugal pump, a plurality of main blades which are axially and equidistantly distributed are fixedly connected in the main body, the main blades are communicated with an inlet and an outlet of the main body, and splitter blades are arranged between adjacent main blades; the main blade is of a forward bending design, and the molded line of the splitter blade is arranged corresponding to the main blade; the inlet of the splitter blade is flush with the inlet of the main blade and is arranged corresponding to the outer edge of the main body, and the length of the splitter blade is smaller than that of the main blade. According to the utility model, under the condition that the blocking of the blade inlet is not increased, the number of effective blades is increased, so that fluid flows more uniformly along the impeller flow channel, flow separation and secondary flow caused by high-speed rotation in the impeller flow channel are reduced, flow field distribution in the impeller is improved, the area and strength of vortex in the impeller are reduced, the energy recovery efficiency and operation stability of the hydraulic turbine are improved, the hydraulic efficiency of the turbine is improved, and the range of a high-efficiency area is widened.

Description

Special turbine impeller with splitter blades

Technical Field

The utility model belongs to the technical field of centrifugal pumps, and particularly relates to a special impeller with a splitter blade for a turbine.

Background

In the industrial processes of petrochemical industry, sea water desalination, urban water supply network and the like, a large amount of residual pressure energy exists, the residual pressure energy is directly decompressed through a pore plate or a decompression valve, the energy is wasted, and the waste of the residual pressure energy can be avoided by replacing the decompression device with the energy recovery device. The centrifugal pump turbine (simply called pump turbine) is a technically and economically effective energy recovery mode, and compared with the traditional water turbine, the pump turbine has the advantages of simple structure, low cost, convenient operation and maintenance, high economical efficiency and the like. The pump is used as a turbine technology to generate electricity in remote rural areas, so that the method is economically feasible, and the living quality of local people can be effectively improved. Because the performance of the original centrifugal pump after directly reversing the pump as a turbine can not be accurately predicted, and the efficiency of the pump as the turbine is generally not higher than the efficiency of the pump working condition, in addition, the pump as the turbine has the problems of noise and vibration in actual operation, the safe and stable operation of a unit is affected, and enterprises are generally reluctant to install an energy recovery device in an industrial process based on the requirement of high reliability of the system. The factors objectively limit the popularization and application of the hydraulic turbine energy-saving technology in industrial residual pressure energy recovery. To the above problems, the applicant developed a special impeller for a turbine which is specially suitable for reverse running of a pump, and the special impeller for the turbine not only remarkably improves the running efficiency of a hydraulic turbine, but also solves the problem of inaccurate prediction of a high-efficiency point of the running of the turbine. However, because the water flows into the impeller asymmetrically in the circumferential direction, even under the design working condition, the impeller still generates non-ideal flows such as axial vortexes, secondary flows and the like, and different forms of vortical movements are formed in the impeller flow channel, so that unstable flows of the fluid are caused, and the energy loss of the fluid is further increased, and therefore, in order to further improve the efficiency and the operation stability of the hydraulic turbine, the unstable flows in the impeller special for the turbine are required to be improved.

Therefore, there is a need to design a turbine-specific impeller with splitter blades to address the above-described problems.

Disclosure of Invention

In order to solve the technical problems, the utility model provides a special turbine impeller with a splitter blade.

In order to achieve the above purpose, the utility model provides a special impeller with a splitter vane for a turbine, which comprises a main body, wherein the main body is arranged on a main shaft of a centrifugal pump, a plurality of main vanes which are axially and equidistantly distributed are fixedly connected in the main body, the main vanes are communicated with an inlet and an outlet of the main body, and splitter vanes are arranged between the adjacent main vanes;

the main blade is of a forward bending design, and the molded line of the split blade is arranged corresponding to the main blade;

the inlet of the splitter blade is flush with the inlet of the main blade and is arranged corresponding to the outer edge of the main body, and the length of the splitter blade is smaller than that of the main blade.

Preferably, the thickness of the inlet of the splitter blade is greater than that of the outlet, and the molded line of the splitter blade is of a smooth and gentle transition structure.

Preferably, the length of the splitter blade is 0.5-0.8 times the length of the main blade.

Preferably, a flow channel is arranged between the adjacent main blades, the inlet width of the flow channel is larger than the outlet width of the flow channel, and the flow channel is arranged in an arc shape; the splitter blades are located at the inlet position of the runner and distributed along the runner.

Preferably, the main body comprises a front cover plate and a rear cover plate which are arranged in parallel, and the main blades and the splitter blades are fixedly connected between the front cover plate and the rear cover plate; the inlet of the runner is arranged corresponding to the outer edges of the front cover plate and the rear cover plate.

Preferably, the front cover plate is fixedly connected with a fluid outlet, and the fluid outlet is communicated with the outlet of the runner.

Preferably, one end of the rear cover plate, which is far away from the front cover plate, is fixedly connected with a hub, and the hub is used for connecting a main shaft of the centrifugal pump; a key slot is formed in the center of the hub; and the back cover plate is provided with a balance hole in a penetrating way.

Preferably, the included angle between the inlets of the adjacent main blades is theta, and the offset angle of the splitter blade is 0.4 theta-0.6 theta.

Compared with the prior art, the utility model has the following advantages and technical effects: the impeller is mainly used for a centrifugal pump special for a turbine, fluid flows in from the outer side of a main body, flows out from an outlet of the main body after being guided by the main blades and the splitter blades, and the pressure change of the fluid drives the main body to rotate in the process so as to drive a main shaft of the centrifugal pump to rotate, so that high-pressure energy of the fluid is converted into mechanical energy or electric energy; according to the utility model, under the condition that the blocking of the blade inlet is not increased, the number of effective blades is increased, so that fluid flows more uniformly along the impeller flow channel, flow separation and secondary flow caused by high-speed rotation in the impeller flow channel are reduced, flow field distribution in the impeller is improved, the area and strength of vortex in the impeller are reduced, the energy recovery efficiency and operation stability of the hydraulic turbine are improved, the hydraulic efficiency of the turbine is improved, and the range of a high-efficiency area is widened.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application, illustrate and explain the application and are not to be construed as limiting the application. In the drawings:

FIG. 1 is a schematic view of the tip construction of a special turbine wheel with splitter blades of the present utility model;

FIG. 2 is a schematic top view of a special turbine wheel with splitter blades according to the present utility model;

FIG. 3 is a schematic view of the bottom end construction of a special turbine wheel with splitter blades according to the present utility model;

FIG. 4 is a schematic view of a splitter blade distribution according to the present utility model;

FIG. 5 is a diagram of the internal flow field of the present utility model in comparison to a conventional impeller;

FIG. 6 is a graph of the two turbine operating characteristics of the present utility model versus a conventional impeller;

in the figure: 1. a main body; 2. a main blade; 3. a splitter blade; 4. a flow passage; 5. a front cover plate; 6. a back cover plate; 7. a fluid outlet; 8. a hub; 9. a key slot; 10. balance holes.

Detailed Description

The following description of the embodiments of the present utility model 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 utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In order that the above-recited objects, features and advantages of the present utility model will become more readily apparent, a more particular description of the utility model will be rendered by reference to the appended drawings and appended detailed description.

Referring to fig. 1-6, the embodiment provides a special impeller with a splitter vane, which comprises a main body 1, wherein the main body 1 is arranged on a main shaft of a centrifugal pump, a plurality of main vanes 2 which are distributed at equal intervals in the axial direction are fixedly connected in the main body 1, and splitter vanes 3 are arranged between the main vanes 2 which are adjacent to an inlet and an outlet of the main body 1 and are communicated with the main vanes 2;

the main blade 2 is of a forward bending design, and the molded line of the splitter blade 3 is arranged corresponding to the main blade 2; the front bending type blade means that the bending direction of the blade from the inlet to the outlet is consistent with the rotation direction of the impeller, and the front bending type blade is obviously different from the conventional impeller blade of the centrifugal pump, so that the front bending type blade is used for meeting the requirement that water flows out of the volute and then enters the impeller without impact, the placing angle of the outlet of the blade is calculated according to the fact that the energy loss of the water flow in the impeller is small, and a molded line is generated according to a certain rule.

The inlet of the splitter blade 3 is flush with the inlet of the main blade 2 and is disposed in correspondence with the outer edge of the main body 1, the length of the splitter blade 3 being smaller than the length of the main blade 2.

The impeller is mainly used for a centrifugal pump special for a turbine, fluid flows in from the outer side of the main body 1, flows out from an outlet of the main body 1 after being guided by the main blades 2 and the splitter blades 3, and in the process, the pressure change of the fluid drives the main body 1 to rotate so as to drive a main shaft of the centrifugal pump to rotate, so that high-pressure energy of the fluid is converted into mechanical energy or electric energy; according to the utility model, under the condition that the blocking of the blade inlet is not increased, the number of effective blades is increased, so that fluid flows more uniformly along the impeller flow channel 4, flow separation and secondary flow caused by high-speed rotation in the impeller flow channel 4 are reduced, flow field distribution in the impeller is improved, the area and strength of vortex in the impeller are reduced, the energy recovery efficiency and operation stability of the hydraulic turbine are improved, the hydraulic efficiency of the turbine is improved, and the range of a high-efficiency area is widened.

The main blades 2 are forwards bent to enable the main blades to have the same bending degree as the rotation direction of the impeller, the bending direction of the blades is consistent with the movement direction of water flow, the impact loss of fluid in the impeller is reduced compared with that of a prototype pump when the fluid is directly reversed, but the volute is of an asymmetric structure, and the fluid reaches an inlet of the impeller after flowing out of the volute, so that the fluid is easy to generate boundary layer separation at She Daona, and then vortex is generated in a blade path, and therefore, the turbine efficiency and the operation stability are both influenced; the splitter blades 3 are located between two adjacent main blades 2 and run the same as the main blades 2 to split the fluid in the flow channels 4.

According to the further optimization scheme, the thickness of an inlet of the splitter blade 3 is larger than that of an outlet, and the molded line of the splitter blade 3 is of a smooth and gentle transition structure. The flow direction of the fluid of the turbine impeller is opposite to that of a conventional water pump impeller, and the process of converting high-pressure energy of the fluid into mechanical energy or electric energy is adopted, so that the fluid enters from the outer edge of the impeller, flows towards the center of the impeller along the flow channel 4, is decelerated and depressurized, finally flows out, and energy is transmitted to the impeller in the process of decelerating and depressurizing to drive the impeller to rotate; the molded lines of the main blade 2 and the splitter blade 3 are smooth transition, so that the resistance of the fluid in high-speed movement is reduced, and the stability of the fluid in the impeller is improved; the inlet thickness of the splitter blades 3 is greater than the outlet thickness, which is considered according to the strength, and the inlet of the impeller is high in pressure, so that the inlet thickness is thick. The thickness of the blade varies according to a linear law.

According to the further optimization scheme, the length of the splitter blade 3 is 0.5-0.8 times of that of the main blade 2, and the splitter blade can effectively improve the efficiency of the special impeller of the turbine under the high-flow working condition and improve the flow state in the flow channel.

In a further optimization scheme, a flow channel 4 is arranged between adjacent main blades 2, the inlet width of the flow channel 4 is larger than the outlet width of the flow channel 4, and the flow channel 4 is arranged in an arc shape; the splitter blades 3 are located at the inlet of the flow channel 4 and distributed along the flow channel 4. The flow channel 4 is formed by surrounding the main body 1 and two adjacent main blades 2 and is mainly used for partitioning the impeller, and meanwhile, the flow channel 4 in arc arrangement is also the action point of fluid pressure; the flow channel 4 has large inlet width and small outlet width, and fluid is guided to flow to the outlet of the impeller along the flow channel 4, so that the impeller is driven to rotate, and the pressure of the fluid is converted into mechanical motion for rotating the impeller; the splitter blades 3 are arranged at the inlet of the flow channel 4, so that the number of effective blades is increased under the condition that the inlet blockage of the blades is not increased, the fluid flows more uniformly along the impeller flow channel 4, the flow separation and secondary flow caused by high-speed rotation inside the impeller flow channel 4 are reduced, and the stability and conversion efficiency are improved.

In a further optimization scheme, the main body 1 comprises a front cover plate 5 and a rear cover plate 6 which are arranged in parallel, and the main blades 2 and the splitter blades 3 are fixedly connected between the front cover plate 5 and the rear cover plate 6; the inlets of the flow channels 4 are arranged corresponding to the outer edges of the front cover plate 5 and the rear cover plate 6; the front cover plate 5 is fixedly connected with a fluid outlet 7, and the fluid outlet 7 is communicated with the outlet of the flow channel 4; a hub 8 is fixedly connected to one end of the rear cover plate 6, which is far away from the front cover plate 5, and the hub 8 is used for connecting a main shaft of the centrifugal pump; a key slot 9 is formed in the center of the hub 8; the back cover plate 6 is provided with a balance hole 10. Furthermore, the inlets of the main blade 2 and the splitter blade 3 are arc-shaped, no sharp angle exists, and the resistance to fluid is reduced. The front cover plate 5 and the rear cover plate 6 clamp the main blades 2 and the splitter blades 3 in the middle, fluid flows between the front cover plate 5 and the rear cover plate 6 and flows from the outer edge to the fluid outlet 7 at the center of the front cover plate 5, so that the protection is good, the dissipation of the fluid is effectively reduced, the pressure loss of the fluid is reduced, and the efficiency is high; the hub 8 and the key groove 9 are used for being connected with a main shaft of the centrifugal pump, so that the impeller drives the main shaft (not shown in the figure) to rotate, and the key groove 9 is internally provided with a connecting key (conventional part, not shown in the figure), so that the stability of connection is improved, and slipping is prevented; the balance hole 10 is used to maintain a constant low pressure in the annular chamber at the back of the impeller, and is one of the most cost-effective ways to reduce the axial force exerted on the impeller, and is provided in conventional technology and will not be described in detail herein.

In a further optimization scheme, the included angle between the inlets of the adjacent main blades 2 is theta, and the offset angle of the splitter blade 3 is 0.4 theta-0.6 theta. And theta is the included angle between two adjacent main blades 2 and is determined according to the number Z of the blades, the value of the included angle is equal to 360/Z, the offset degree of the splitter blade 3 reflects the position of the splitter blade 3 relative to the main blades 2, 0.5 theta indicates that the splitter blade is positioned between the two main blades, 0.4 theta indicates that the position of the splitter blade is close to the suction surface, and 0.6 theta indicates that the position of the splitter blade is close to the pressure surface.

As shown by the comparison of the turbine wheel and the internal flow field distribution of the present application in FIG. 5, the swirl between the vane flow passages 4 after the addition of the splitter vanes 3 is significantly improved.

According to the comparison of the conventional turbine wheel in fig. 6 and the external characteristic curve of the turbine, after the splitter vane 3 is added, the required water head of the turbine is reduced under the same flow, and the operation efficiency of the turbine is obviously improved from a high-efficiency point to a high-flow working condition.

In the description of the present utility model, it should be understood that the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the present utility model, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present utility model.

The above embodiments are only illustrative of the preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model, and various modifications and improvements made by those skilled in the art to the technical solutions of the present utility model should fall within the protection scope defined by the claims of the present utility model without departing from the design spirit of the present utility model.

Claims (8)

1. A special turbine wheel with splitter blades, characterized in that: the centrifugal pump comprises a main body (1), wherein the main body (1) is arranged on a main shaft of the centrifugal pump, a plurality of main blades (2) which are axially and equidistantly distributed are fixedly connected in the main body (1), the main blades (2) are communicated with an inlet and an outlet of the main body (1), and a flow dividing blade (3) is arranged between every two adjacent main blades (2);

the main blade (2) is of a forward bending design, and the molded line of the splitter blade (3) is arranged corresponding to the main blade (2);

the inlet of the splitter blade (3) is flush with the inlet of the main blade (2) and is arranged corresponding to the outer edge of the main body (1), and the length of the splitter blade (3) is smaller than that of the main blade (2).

2. The splitter vane turbine-dedicated impeller of claim 1, wherein: the thickness of an inlet of the splitter blade (3) is larger than that of an outlet, and the molded line of the splitter blade (3) is of a smooth and gentle transition structure.

3. The splitter vane turbine-dedicated impeller of claim 1, wherein: the length of the splitter blade (3) is 0.5-0.8 times the length of the main blade (2).

4. The splitter vane turbine-dedicated impeller of claim 1, wherein: a flow channel (4) is arranged between the adjacent main blades (2), the inlet width of the flow channel (4) is larger than the outlet width of the flow channel (4), and the flow channel (4) is arranged in an arc shape; the splitter blades (3) are positioned at the inlet position of the runner (4) and distributed along the runner (4).

5. The splitter vane turbine-dedicated impeller of claim 4, wherein: the main body (1) comprises a front cover plate (5) and a rear cover plate (6) which are arranged in parallel, and the main blades (2) and the splitter blades (3) are fixedly connected between the front cover plate (5) and the rear cover plate (6); the inlet of the runner (4) is arranged corresponding to the outer edges of the front cover plate (5) and the rear cover plate (6).

6. The splitter vane turbine-dedicated impeller of claim 5, wherein: the front cover plate (5) is fixedly connected with a fluid outlet (7), and the fluid outlet (7) is communicated with the outlet of the runner (4).

7. The splitter vane turbine-dedicated impeller of claim 5, wherein: one end of the rear cover plate (6) far away from the front cover plate (5) is fixedly connected with a hub (8), and the hub (8) is used for connecting a main shaft of a centrifugal pump; a key slot (9) is formed in the center of the hub (8); balance holes (10) are formed in the rear cover plate (6) in a penetrating mode.

8. The splitter vane turbine-dedicated impeller of claim 1, wherein: the included angle between the inlets of the adjacent main blades (2) is theta, and the offset angle of the splitter blade (3) is 0.4 theta-0.6 theta.