Double-water-outlet type water turbine

Abstract

The invention belongs to the technical field of water turbines, and particularly relates to a double-water-outlet type water turbine which comprises a shell provided with a spiral volute inlet section used for water inflow and two quasi-spiral double-water-outlet sections used for water outflow, and the two quasi-spiral double-water-outlet sections are symmetrically arranged on the two sides of the spiral volute inlet section; the pump shaft is rotationally arranged in the shell, the outer side of the middle of the pump shaft is in shaft connection with an impeller, the impeller is arranged between the spiral volute inlet section and the quasi-spiral double-water-outlet section, and the spiral volute inlet section is communicated with the quasi-spiral double-water-outlet section through the impeller; fluid passes through the impeller and flows into the corresponding quasi-spiral double water outlet sections from the two sides of the impeller. Compared with a traditional water turbine impeller, the axial thrust borne by the impeller is reduced, the pressure pulsation is reduced, and stable operation is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic turbines, and particularly relates to a double-outlet hydraulic turbine. Background Art

[0003] Traditional hydraulic turbines usually include fixed guide vanes, movable guide vanes, etc. They have many components, complex structures, high costs, and long investment recovery periods. For the medium and low specific speed ranges, the outflow direction of the fluid in traditional centrifugal and mixed-flow hydraulic turbines is perpendicular to the outflow direction, which easily causes problems such as complex pipeline layout. As the flow rate increases, the axial thrust on the runner of traditional hydraulic turbines becomes larger, the pressure pulsation becomes more obvious, and the problem of unstable operation becomes more prominent. Therefore, there is an urgent need for a double-outlet hydraulic turbine to solve these problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a double-outlet hydraulic turbine to solve the above problems.

[0005] To achieve the above purpose, the present invention provides the following solution:

[0006] A double-outlet hydraulic turbine, comprising:

[0007] A housing provided with a spiral volute inlet section for water inlet and two quasi-spiral double-outlet sections for water outlet. The two quasi-spiral double-outlet sections are symmetrically arranged on both sides of the spiral volute inlet section;

[0008] A pump shaft rotatably arranged in the housing. An impeller is axially connected to the outer side of the middle of the pump shaft. The impeller is arranged between the spiral volute inlet section and the quasi-spiral double-outlet sections, and the spiral volute inlet section and the quasi-spiral double-outlet sections are communicated through the impeller;

[0009] The fluid flows through the impeller and respectively flows into the corresponding quasi-spiral double-outlet sections from both sides of the impeller.

[0010] Runner structures are respectively arranged on both sides of the impeller. The runner structures are fixedly connected to the hub, and the runner structures include a plurality of blades circumferentially and equally spaced;

[0011] The inlet setting angle of the blade is β 1 , and the outlet setting angle of the blade is β 2 , and the wrap angle of the blade is

[0012] Optionally, the calculation formula for the inlet setting angle of the blade β 1 is:

[0013]

[0014] where vm1 is the component velocity of the absolute velocity in the axial direction, with the unit of m / s; u 1 is the circumferential velocity at the inlet, with the unit of m / s; v u1 is the component velocity of the absolute velocity in the circumferential direction, with the unit of m / sD 1 is the impeller inlet diameter, with the unit of m; n is the rotational speed, with the unit of r / min; Q r is the designed flow rate, with the unit of m 3 / s; b 1 is the blade inlet width, with the unit of m; ψ 1 is the blade inlet blockage coefficient; δ 1 is the circumferential thickness of the blade inlet edge, with the unit of m; Z is the number of blades; R 1c is the radius of the centroid of the generatrix of the blade inlet edge, with the unit of m.

[0015] Optionally, the outlet setting angle of the blade is β 2 The calculation formula is:

[0016]

[0017] wherein, u 2 is the circumferential velocity at the impeller outlet, with the unit of m / s; Q r is the designed flow rate, with the unit of m 3 / s; A 2 is the actual axial flow cross-sectional area of the liquid at the impeller outlet, m 2 .

[0018] Optionally, the blade is a backward-curved blade, and the number of blades is 6 to 10.

[0019] Optionally, the stagger angle between the two runner structures is where z is the number of blades.

[0020] Optionally, the hub diameter is the same as the impeller outer diameter.

[0021] Optionally, covers are respectively axially connected to both ends of the impeller.

[0022] Optionally, a packing ring for sealing is provided between the housing and the pump shaft. The packing ring is sleeved on the pump shaft. The pump shaft is rotatably connected to the housing through a bearing, and a bearing body gland is fixedly connected to the housing. The bearing body gland is rotatably arranged outside the pump shaft.

[0023] Optionally, a coupling is axially connected to one end of the pump shaft.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] In use, water flow enters through the spiral volute inlet section and into the impeller. The impeller rotates under the impact of the water flow, driving the pump shaft to rotate, enabling the impeller to drive the pump shaft to generate mechanical energy. After generating mechanical energy, the water flow flows into the corresponding quasi-spiral double-outlet section from both sides of the impeller. Since both sides of the impeller are water outlets, the two ends of the impeller reach mechanical balance. Compared with the impeller of a traditional water turbine, the axial thrust it receives is reduced, the pressure pulsation is reduced, and stable operation is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings:

[0027] Figure 1 is a sectional view of the structure of the present invention;

[0028] Figure 2 is a schematic diagram of the meridian plane of the impeller of the present invention after extending the hub;

[0029] Figure 3 is a schematic diagram of the structure of the impeller of the present invention from the first perspective;

[0030] Figure 4 is a schematic diagram of the structure of the impeller of the present invention from the second perspective;

[0031] Figure 5 is a schematic diagram for comparing the external characteristics of the impeller of the present invention and the original impeller;

[0032] Among them, 1, spiral volute inlet section; 2, hub; 3, impeller; 4, cover plate; 5, quasi-spiral double-outlet section; 6, bearing body gland; 7, packing ring; 8, coupling. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0034] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0035] Referring to Figures 1 to 5 , the present invention discloses a double-outlet water turbine, including:

[0036] A housing is provided with a spiral volute inlet section 1 for water inlet and two quasi-spiral double outlet sections 5 for water outlet. The two quasi-spiral double outlet sections 5 are symmetrically arranged on both sides of the spiral volute inlet section 1.

[0037] A pump shaft is rotatably arranged in the housing. An impeller 3 is axially connected to the outer side of the middle of the pump shaft. The impeller 3 is arranged between the spiral volute inlet section 1 and the quasi-spiral double outlet section 5. The spiral volute inlet section 1 and the quasi-spiral double outlet section 5 are communicated through the impeller 3.

[0038] The fluid passes through the impeller 3 and flows into the corresponding quasi-spiral double outlet sections 5 from both sides of the impeller 3 respectively.

[0039] During use, water flows into the impeller 3 from the spiral volute inlet section 1. The impeller 3 rotates under the impact of the water flow, driving the pump shaft to rotate, so that the impeller 3 drives the pump shaft to generate mechanical energy. After generating mechanical energy, the water flow flows into the corresponding quasi-spiral double outlet sections 5 from both sides of the impeller 3 respectively. Since both sides of the impeller 3 are water flow outlets, the two ends of the impeller 3 reach mechanical balance. Compared with the impeller of a traditional water turbine, the axial thrust it receives is reduced, the pressure pulsation is reduced, and stable operation is achieved.

[0040] As an additional implementation method, the housing is provided with an inlet and an outlet. The inlet is communicated with the spiral volute inlet section 1, and the outlet is communicated with the two quasi-spiral double outlet sections 5. The inlet and outlet of the housing are on the same horizontal line and perpendicular to the axis of the pump shaft.

[0041] By setting like this, compared with the traditional centrifugal and mixed-flow water turbines, the outflow direction of the fluid is perpendicular to the outflow direction, resulting in problems such as complex pipeline layout. In the present invention, the inlet and outlet directions are on the same horizontal line, making the pipeline layout more convenient.

[0042] As an optional implementation method, runner structures are respectively arranged on both sides of the impeller 3. The runner structures are fixedly connected to the hub 2. The runner structures include a plurality of blades circumferentially arranged at equal intervals.

[0043] The inlet blade setting angle is β 1 , and the outlet blade setting angle is β 2 , and the blade wrap angle is

[0044] As an optional implementation method, the calculation formula for the inlet blade setting angle of β 1 is:

[0045]

[0046] wherein, v m1 is the component velocity of the absolute velocity in the axial direction, with the unit of m / s; u1 is the circumferential velocity at the inlet, with the unit of m / s; v u1 is the component velocity of the absolute velocity in the circumferential direction, with the unit of m / s D 1 is the impeller inlet diameter, with the unit of m; n is the rotational speed, with the unit of r / min; Q r is the designed flow rate, with the unit of m 3 / s; b 1 is the blade inlet width, with the unit of m; ψ 1 is the blade inlet blockage coefficient; δ 1 is the circumferential thickness of the blade inlet edge, with the unit of m; Z is the number of blades; R 1c is the radius of the centroid of the generatrix of the blade inlet edge, with the unit of m.

[0047] Among them, the included angle of the blade is a given value.

[0048] As an alternative implementation, the outlet setting angle of the blade is β 2 The calculation formula is:

[0049]

[0050] Among them, u 2 is the circumferential velocity at the impeller outlet, with the unit of m / s; Q r is the designed flow rate, with the unit of m 3 / s; A 2 is the actual axial flow cross-sectional area of the liquid flow at the impeller outlet, m 2 .

[0051] As an alternative implementation, the blade is a backward-curved blade, and the number of blades is 6 to 10.

[0052] As an alternative implementation, the stagger angle between the two runner structures is where z is the number of blades.

[0053] As an alternative implementation, the hub 2 wheel diameter is the same as the impeller 3 outer diameter.

[0054] The main components of the present invention include a spiral volute inlet section 1, an impeller 3, and a quasi-spiral double-outlet section 5. High-pressure fluid flows into the impeller 3 from the spiral volute inlet section 1, pushing the impeller 3 to rotate, and the pressure energy of the fluid is converted into the mechanical energy of the rotation of the impeller 3. The fluid flows out from two opposite directions of the impeller 3 respectively and enters the quasi-spiral double-outlet section 5, where it converges into a single fluid and flows out along a direction perpendicular to the axis of the pump shaft.

[0055] The impeller 3 is installed in the housing through a pump shaft.

[0056] The impeller 3 includes two symmetrically arranged runner structures, and the runner structure is composed of a number of blades arranged at equal intervals in the circumferential direction. Among them, the inlet setting angle of the blade is β 1 , and the outlet setting angle of the blade is β 2 , and the wrap angle of the blade is

[0057] The inlet setting angle β of the blade 1 can be calculated according to the following formula:

[0058]

[0059] Among them, v m1 is the component velocity of the absolute velocity in the axial direction, m / s; u 1 is the circumferential velocity at the inlet, m / s; v u1 is the component velocity of the absolute velocity in the circumferential direction, m / s.

[0060] Since the outlet section is quasi-spiral, to ensure that the fluid flows out of the impeller stably, the velocity moment of the fluid flowing out of the impeller is equal to the velocity moment of the fluid entering the spiral outlet section. Therefore, the outlet setting angle of the impeller blade can be calculated according to the following formula:

[0061]

[0062] Among them, u 2 is the circumferential velocity at the impeller outlet, with the unit of m / s; Q r is the design flow rate, with the unit of m 3 / s; A 2 is the actual meridional flow cross-sectional area at the impeller outlet, m 2 .

[0063] Considering the machining and manufacturing and the wrap angle size, the number of blades is generally 6-10. When the wrap angle is small, more blades can be selected; when the wrap angle is large, fewer blades can be selected.

[0064] The blade thickness should be set considering the machining process, water head and strength issues comprehensively.

[0065] Extend the rear cover plate of the impeller to be the same as the outer diameter of the impeller.

[0066] The blades of the symmetric impeller are staggered, and the staggering angle is usually where z is the number of blades.

[0067] The specific parameters of the impeller 3 are shown in Table 1.

[0068] Table 1 Impeller design parameters

[0069]

[0070] By adopting the impeller 3 with the special design of the present invention, the overall hydraulic efficiency has been improved to varying degrees, with a maximum increase of about 1.5%. In addition, the staggered arrangement of the blades significantly reduces the pressure pulsation, prolongs the service life of the water turbine, and enhances the stability during operation.

[0071] As an alternative embodiment, cover plates 4 are respectively axially connected to both ends of the impeller 3.

[0072] As an alternative embodiment, a packing ring 7 for sealing is provided between the housing and the pump shaft. The packing ring 7 is sleeved on the pump shaft. The pump shaft is rotatably connected to the housing through bearings, and a bearing body gland 6 is fixedly connected to the housing. The bearing body gland 6 is rotatably arranged outside the pump shaft.

[0073] As an alternative embodiment, a coupling 8 is axially connected to one end of the pump shaft.

[0074] Compared with traditional water turbines, the present invention has the following advantages:

[0075] The inlet and outlet directions are on the same horizontal line, making the pipeline layout more convenient; the structure is simple, the volume is small, the cost is low, and the cost recovery period is significantly shortened; the hub 2 of the impeller is extended to be the same as the outer diameter of the impeller, and the fluid is divided into two streams before flowing into the impeller, reducing the interaction between the fluids and improving the efficiency under small flow conditions; the blades of the symmetric impeller are staggered, which can effectively reduce the pressure pulsation and enhance the operation stability.

[0076] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0077] The above-described embodiments are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A double-outlet water turbine, characterized in that: include: The housing is provided with a spiral volute inlet section (1) for water intake and two quasi-spiral double water outlet sections (5) for water discharge, wherein the two quasi-spiral double water outlet sections (5) are symmetrically arranged on both sides of the spiral volute inlet section (1); A pump shaft is rotatably arranged in the housing, an impeller (3) is axially connected to the outer side of the middle portion of the pump shaft, the impeller (3) is arranged between the spiral volute inlet section (1) and the quasi-spiral double water outlet section (5), and the spiral volute inlet section (1) and the quasi-spiral double water outlet section (5) are connected via the impeller (3); The fluid passes through the impeller (3) and flows into the corresponding quasi-spiral double water outlet sections (5) from both sides of the impeller (3).

2. A double-outlet water turbine according to claim 1, characterized in that: The impeller (3) is provided with a runner structure on both sides, the runner structure is fixedly connected to the hub (2), and the runner structure comprises a plurality of blades arranged at equal intervals in the circumferential direction; The inlet placement angle of the blade is β1, the outlet placement angle of the blade is β2, and the wrap angle of the blade is 3. A double-outlet water turbine according to claim 2, characterized in that: The calculation formula for the blade inlet placement angle β1 is: Among them, v m1 is the axial component of the absolute speed, in m / s; u1 is the circumferential speed at the inlet, in m / s; v u1 is the component of the absolute speed in the circumferential direction, in m / s; D1 is the impeller inlet diameter, in m; n is the speed, in r / min; Q r is the design flow rate, in m 3 / s; b1 is the blade inlet width, in m; ψ1 is the blade inlet crowding coefficient; δ1 is the blade inlet edge circumferential thickness, in m; Z is the number of blades; R 1c It is the radius of the centroid of the blade inlet generatrix, in m.

4. A double-outlet water turbine according to claim 2, characterized in that: The calculation formula of the outlet placement angle β2 of the blade is: Where u2 is the circumferential velocity at the impeller outlet, in m / s; Q r is the design flow rate, in m 3 / s; A2 is the actual axial liquid flow through the water cross-sectional area at the impeller outlet, m 2 .

5. A double-outlet water turbine according to claim 2, characterized in that: The blades are backward curved blades, and the number of the blades is 6 to 10.

6. A double-outlet water turbine according to claim 2, characterized in that: The staggered angle of the two rotating wheel structures is Where z is the number of blades.

7. A double-outlet water turbine according to claim 2, characterized in that: The wheel diameter of the wheel hub (2) is the same as the outer diameter of the impeller (3).

8. A double-outlet water turbine according to claim 1, characterized in that: Cover plates (4) are axially connected to both ends of the impeller (3).

9. A double-outlet water turbine according to claim 1, characterized in that: A packing ring (7) for sealing is provided between the housing and the pump shaft. The packing ring (7) is sleeved on the pump shaft. The pump shaft is rotatably connected to the housing via a bearing. A bearing body pressure cover (6) is fixedly connected to the housing. The bearing body pressure cover (6) is rotatably arranged on the outside of the pump shaft.

10. A double-outlet water turbine according to claim 1, characterized in that: One end of the pump shaft is axially connected with a coupling (8).

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