RU2455521C2 - Kazachenko hydraulic hpp unit, guide vanes, impeller, wheel seal, and flow regulator - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: unit is intended to be used at derivational and reservoired HPP with inconsiderable vibration of after-bay level with wide ranges of water head and flow rate. Lower end of vertical shaft of the unit with operating spherical surface is borne against the centre plate. Cone-shaped tray is rigidly attached to the shaft and impeller. Outlet tubes with variable and fixed cross section area are tangentially attached to the above cone-shaped tray. One end of bent vanes is fixed in the guide vanes in external rim and the opposite end is attached to the rim which envelops the shaft. Vanes are made at a tangent to outlet section plane. Upper rib of vane is oriented in radial plane and inclined from internal rim to external rim, and lower rib is oriented horizontally. Seal of the impeller consists of two flexible elastic rings with the chute profile the bottom of which faces the top. Some sides of those are tightly attached to the sealed parts and the opposite convex sides contact each other. Centrifugal water flow regulator includes balancing levers, rods and a slide on the unit shaft, and it is arranged in protection casing in the flowing water flow.

EFFECT: use of the unit contributes to increase in the power, efficiency and high speed, and allows simplifying, cheapening and accelerating the HPP construction.

7 cl, 17 dwg

Description

The invention relates to hydropower.

The main field of application for derivational and dam hydropower plants on rivers with slight fluctuations in the level of the downstream with different values of flow and pressure and a large range of turbine power, including more than 500 thousand kW. Known reactive rotary-blade axial and propeller hydraulic turbines with a vertical shaft. In units with these turbines, the generator rotor is located on the upper end of the shaft, and the impeller is on the lower end [G. Krivchenko Hydraulic machines, turbines and pumps. - M .: Energy, 1978, Fig. 22].

The flow of water, passing the directing apparatus, falls on the impeller blades, from which it flows into the suction pipe. The suction pipe allows you to use the energy corresponding to the height of the turbine above the downstream and a significant part of the kinetic energy that water has when exiting the impeller. The possibility of using kinetic energy to a large extent determines the efficiency of turbines. The disadvantages of these turbines are:

1. The need to build a suction pipe at the base of the dam and the spiral chamber, requiring a large amount of excavation and concrete work.

2. Insignificant speed of twisting of the flow (or its absence) in the impeller, which does not allow to reduce the pressure below it to a significant extent.

3. The shaft is tensile.

4. The impossibility of the unit using the reactive action of the flow coming out of the pipe.

5. Heavy duty turbine bearings.

Common features of these units with the proposed technical solution are the diffusivity of the flow path below the impeller and the creation of a reduced pressure in the flow under the impeller.

The closest analogue adopted for the prototype is a hydropower plant hydraulic unit containing an impeller with a seal and an attached pallet equipped with exhaust pipes, a vertical shaft resting on the thrust frame with a lower end, and a guiding apparatus (RU 2313001 C2, 12.20.2006) .

In addition to the jet impeller, the unit also contains a coaxial active wheel that uses the kinetic energy of the stream exiting the jet wheel and transmitting it to the shaft with a gear increasing the speed and changing the direction of rotation of the gearbox. A shaft extends along the entire height of the jet impeller and the cylindrical tray attached to it, which contributes to a stable swirling of the flow. From the exhaust pipes of an elongated cross section attached tangentially to the pallet, water jets are released into the atmosphere, having a reactive effect in the passing direction of rotation on the pallet.

The disadvantages of this unit are the low swirling speed of the water flow in the reactive impeller, the presence of bulky active impeller and gearbox, which complicates the design of the hydraulic unit and increases the specific metal consumption.

The objective of the present invention is to create a cheap highly efficient hydraulic unit with lower capital costs for the construction of hydropower plants due to:

1. Impeller devices in combination with a guide vane.

2. Increasing the swirling speed of the water flow in the guide apparatus and the impeller.

3. A more complete use of the kinetic components of the flow energy and the exclusion of water leaks, which will increase the power (including specific), efficiency and speed of the turbine.

4. Exceptions to the design of the active impeller and cumbersome planetary gear.

5. The use of a spherical work surface on the lower end of the shaft.

The problem is solved and the technical result is achieved by the fact that the hydraulic unit of the hydroelectric power station contains an impeller with a seal and an attached pallet equipped with exhaust pipes, a vertical shaft resting on the thrust frame with a lower end, and a guide apparatus, the shaft has a spherical bearing surface, a guide apparatus and the upper part of the impeller is made in the form of coaxial pipes of the same diameter and installed at a distance of the working gap between them, the impeller seal is placed between the rim fixed to the rim wheel shell and the guide apparatus, the pallet has a conical shape and the outlet tube are made variable and fixed by the cross-sectional area and are arranged at the bottom of the pallet, the assembly is provided with a water flow regulator.

In addition, the blades of the guide apparatus and the impeller are curved in the opposite direction.

Figure 1 shows a vertical section of a hydraulic unit. Figure 2 - section aa of figure 1 (the arrow shows the direction of rotation of the pallet, the gates are not shown); figure 3 is a view along arrow C of figure 2 (the gate of the exhaust pipe); figure 4 is a section bb In figure 3; figure 5 - node In figure 1 (shaft seal with an inner rim of the guide apparatus); in Fig.6 - section FJ in Fig.5 (on top of the rims of the guide apparatus, the arrows show the direction of flow when leaving the apparatus, and the dashed lines indicate the lower ends of the blades); in Fig.7 - section II Fig.6 (the diameter of the guide apparatus); in Fig.8 is a plot of the scan of the inner surfaces of the outer rims of the guide vane and the impeller (with dashed lines indicate the fixing points of the blades, thin straight lines indicate the meridian grid and arrows indicate the direction of water flow); figure 9 is a section CC of figure 1 (top view of the impeller, the solid arrow shows the direction of rotation of the wheel, and the dotted line shows the direction of reflected flow); figure 10 is a section DD DD figure 9 (section of the wheel along the axis); figure 11 is a section of the MR of figure 9 (section of the blade plane, orthogonal to the upper rib and passing through the end of the lower rib); in Fig.12 - node C of Fig.1 (radial section of the impeller seals with dashed lines in the working position); in Fig.13 - node D of Fig.1 (longitudinal section of a centrifugal water flow controller with the outline of the protective casing with dashed lines, and arrows - the direction of movement of the parts); on Fig - rotated 90 ° around the axis of Fig.13 (controller with conditionally not shown balancers and rods); in Fig.15 is a view along arrow A of Fig.14 (drive of the regulatory body), Fig.16 is a node A of Fig.15 (gear on the axis in engagement with the rails); on Fig - section KK (Fig.15) (a transverse section of the shaft and gears along the axis schematically).

The hydraulic unit (FIGS. 1-17) contains on a vertical shaft 1 (shown not hollow) installed with a lower end with a spherical bearing surface on a thrust frame 2, and with a top end in a guide bearing 3, a tapered pallet supported by the bottom 4. Tangent to the generatrix of the cone of the pallet attached exhaust pipes 6 (Fig.1, 2) with gates 7 (Fig.3, 4). The gate moves in the grooves 8 and is fixed in the required position by means of a bolt 9 pressing the seal 10. A side wall 11 of the pipe 6 is attached to the end of the gate, and the upper wall 12 of the pipe 6 is attached to the pallet. Water enters the unit from the opposite sides of the shaft through two supply pipes 13 into the supply pipe 14 with the conical part 15 and further into the cylindrical guide apparatus. The blades 16 (FIGS. 5, 6, 7) of the guide vane are fixed to the outer 17 and inner rim 18. The gap between the shaft and the rim 18 is sealed with rings 19 and 20. To the upper cylindrical part 21 (FIGS. 9, 10) of the impeller and lower blades 23 are attached to the conical part 23. The wheel seal 24 consists of an inner ring 25 (FIGS. 1, 12) fixed externally to the guide apparatus and contacting the opposite side with the ring 26. It is fixed to the conical shell 27 connected to the cylindrical part 21 of the wheel rim . Similarly made and the seal 28 of the shaft 1 with the end of the water supply pipe (figure 1). The centrifugal regulator (Fig.13) is enclosed in a casing 29 (Fig.1, 14). Mounted on the shaft, the balancers 30 are connected by rods 31 with the slider 32. Two gear racks 33 (Fig. 15, 16) are movably fixed on the slide, connected to the regulating body 34, which moves along the shaft in the conical part 15 of the water supply pipe. On the slider along the slots motionless from two diametrically opposite sides fixed two gear racks 35 (Fig.16, 17), rotating gears 36 mounted on the shaft axles 37.

Water is supplied to the unit between the shaft and the wall of the pipe 14 through the supply pipes 13 (Fig. 1). Initially, this flow receives rotation in the associated direction of twisting by the blades 16 (Fig.6) of the guide apparatus and enters the impeller. Passing the blades 23 (Fig. 9), the flow rotates the wheel, the shaft 1 and the conical pallet 5. The flow reflected from the working surfaces of the blades descends horizontally at an acute angle to the surface of the conical pallet 5. A rotating and expanding flow is pressed against it by centrifugal force and creates pressure reduction (depression) in the pan with the highest value in the center. At the same time, the rotating flow moves down. Under the influence of gravity and centrifugal force, the flow leaves the pan, divided into exhaust pipes 6 (Fig.1, 2). Thus, the wheel and the pallet function as a suction pipe. The exhaust streams emitted into the atmosphere in the horizontal direction at the downstream level by reactive action rotate the pan in the direction of the associated turbine.

Therefore, the unit allows you to utilize currently emitted 1-3% of the kinetic energy on the used units in the suction pipe as a result of contact of water with the walls at a great distance and loss when leaving it with a flow rate. These losses are more significant at low and medium pressures (Krivchenko GI Hydraulic machines, turbines and pumps. - M .: Energy, 1978, p. 94-97), Smirnov I.N. Hydraulic turbines and pumps. - M.: Higher School, 1969, p.142-149). They are considered inevitable. “Kinetic energy with an outlet speed from the suction pipe is assigned within 1-3%” (Hydropower Installations, edited by D.S. Shchavelev, 2nd ed., Leningrad, Energoizdat, 1981, p.142-149).

The moment of rotation of the turbine from the outgoing stream is equal to the product of its reactive force by the moment arm. The size of the shoulder exceeds the length of the wheel blade and depends on the value of the angle θ (taper and pallet length).

As is known, in turbines, the angle θ can be increased to 12-14 ° and even more, without causing an increase in losses, but even getting a slight decrease. For this purpose, the flow behind the impeller should not be axial, but have a small twist (Krivchenko GI Hydraulic machines, turbines and pumps. - M .: Energy, 1978, p. 94-97). In the proposed impeller of the unit, the flow swirling speed is much higher than in the known ones. Significant centrifugal force in the pan allows you to significantly increase the angle θ. Its value is limited by factors of structural strength and turbine speed. Increasing the angle allows to reduce the length of the pan with the same suction effect, which is structurally important. On the way of movement in the pan to the exhaust pipes, the rotation speed of the stream decreases due to friction, vortex losses and its expansion. Under the action of centrifugal force, the rotating part of the unit stably occupies a vertical position due to the spherical bearing surface of the shaft. This radically facilitates the working conditions of bearings.

The cross-sectional area of the exhaust pipes changes to form the outgoing flows at the wall of the pallet, depending on their speed. The regulation is carried out by the gate 7, which is moved in the grooves 8 of the pallet. The gate is fixed in position by a bolt 9, which is moved in the slot of the cone, which presses the seal 10. The section of the exhaust pipe is trapezoidal, unequal, with a varying length of the bases. The peculiarity of the aggregate is the accumulation of the kinetic component of the energy of the flow in the guiding apparatus (by twisting it) and in the conical tray (by deviating it from the axis of the aggregate). This stored energy is used in the following adjacent sections of the flow path - in the impeller and in the exhaust pipes.

A passing stream of water gives energy to the impeller and the sump when exiting the exhaust pipes by reactive action. The flow energy, both potential and kinetic components of it, is used in the turbine completely, with the exception of the inevitable friction losses in the flow path and local vortex when changing magnitude, direction and speed. From the point of view of the completeness of the use of the kinetic energy component, there is no need for an active impeller with a reducer or a suction pipe. The design of the unit reduces the influence of unsteady processes. Using it gives an increase in power, efficiency and speed, it will simplify, reduce the cost and speed up the construction of hydroelectric power stations, eliminate cases of flooding of the turbine hall in emergency situations.

Known guide apparatus containing curved blades (RU 2313001 C2, 12.20.2006). Its disadvantage is the large overall dimensions.

The objective of the invention is to reduce the size.

The solution to the problem lies in the fact that in a guiding apparatus containing curved blades, the blade is fixedly attached at one end to the inner rim, and peripheral to the outside and is made tangential to the plane of the output section of the apparatus, and the blades overlap its entire section in the vertical direction, the upper the blade edge is oriented in the radial plane with an inclination to the outer rim, and the bottom is horizontal.

In addition, the gap between the inner rim and the shaft is sealed with flexible elastic rings - the lower rectangular cross-section, freely rotating on the shaft, and the upper triangular cross-section, mounted with an interference fit on the shaft and pressing the lower to the end of the rim.

The proposed guide apparatus (Fig. 5, 6, 7) is made in a coaxial impeller pipe with a diameter equal to the diameter of the outer rim of the wheel. The gap between them is 1.5-2.5 mm. The blades 16 are fixedly attached by the peripheral end to the outer rim 17 and the other to the rim 18 covering the shaft 1 of the blade. The blades 16 are made tangential to the plane of the output section of the apparatus with the horizontal direction of the lower ribs. The curvature of the blades of the guide apparatus and the impeller has a counter direction. Preferably fewer blades in the guide vane than in the impeller. In the guide apparatus, the flow swirls and receives an adapted direction of movement to the working surface of the impeller blades with a more favorable angle of meeting (Fig. 8). The working surface of the blade 16 has a slope from the inner rim 18 to the outer 17 and from the upper rib, oriented in the radial plane, to the horizontal lower. The blades of the guide vane overlap its cross section in the vertical direction. The angle of coverage of the blade of the inner rim is greater than the outer. This ensures the twisting of the stream and its high speed of rotation (circumferential) in the peripheral part (Fig.6, 7). In turn, the impeller blade 23 accepts a large part of the dynamic load from the flow also by the peripheral part with a large torque arm. Of insignificant length and width, the gap between the shaft and the rim 18 is sealed with two rings made of synthetic materials, for example rubber-fabric coated with fluoroplastic surfaces contacting each other. The lower rectangular section of the ring 19 is in contact with the end face of the rim 18 and freely rotates on the shaft 1, and the upper ring 20 of the triangular section is made with a tight fit on the shaft and presses the lower one to the rim. The seal virtually eliminates the leakage of water, does not reduce the flow area, easy to manufacture and operate. The seal of the gap (one) between the shaft and the rim works more efficiently than with analogues due to the axial direction of flow and the small length of the gap, especially since the pressure drop across the top and bottom of the seal is insignificant.

Known impeller with curved blades fixed to the inner rim of the blades (RU 2313001 C2, 12.20.2006).

The disadvantages of these wheels are:

1. Cantilever fixing of the blades, subject to high loads, requiring appropriate strength in the root sections.

2. Inevitable water leakage between the ends of the blades and the wall of the impeller chamber.

These disadvantages are eliminated in the impeller with curved blades fixed to the inner rim, which contains an outer rim made with a cylindrical part at the top and a conical bottom, to which the peripheral ends of the blades are attached with the upper part made vertically to the cylindrical part, and the lower curved to the conical, the upper edge of the blade is radially oriented, and the lower is horizontal.

The proposed impeller (Fig.9, 10), in addition to the inner one, also contains an outer rim with a cylindrical part 21 at the top and a conical part 22 at the bottom. The blades 23 are fixed to the rim (Fig. 9), the upper part of which is made vertical, and the lower one is curved. The upper edge of the blade has a radial direction, and the lower is horizontal. Curved from the vertical direction to the horizontal blades are broadened from the shaft to the periphery and cover the entire section of the wheel in the vertical direction.

The turbines used have a significant drawback - the complicated design of the impeller seals, which do not exclude the leakage of water in the sealing gap. Their principle of operation is based on creating resistance to the movement of water in the sealable gap. The applied structural types of seals: slotted, slotted with grooves, labyrinth, comb or comb with grooves, allow water to flow through the gaps [I. Smirnov Hydraulic turbines and pumps. - M.: Higher School, 1969, p.90-93].

A closer analogue to the proposed seal is the impeller seal described above, consisting of two elastic flexible rings with a gutter profile, the bottom facing up, hermetically fixed on one side to the parts to be sealed, and the opposite convex sides contacting each other, the reverse surfaces of which are subject to the working pressure of water summed up from the bottom (RU 2313001 C2, 12.20.2006).

Its principle of operation is based on locking the gap between the stationary and rotating parts by flexible elements using the working pressure of water.

Its disadvantage is inaccessibility during installation and repair.

This disadvantage is eliminated in the sealing of the impeller, consisting of two elastic flexible rings with the profile of the trough, the bottom facing up, hermetically fixed on one side to the parts to be sealed, and the opposite convex sides in contact with each other, the reverse surfaces of which are exposed to the working pressure of water supplied from the bottom up. the rings are placed at the same level between the parts being sealed, the inner ring being fixed to the part being sealed with a side with a smaller diameter.

The seal 24 (Fig) is placed in a conical socket outside the flow path of the turbine. It is installed between the outer side of the outer rim of the guide vane and the rim 27 directly connected to the cylindrical part 21 of the rim of the wheel. It does not wear out by the flow of water, does not give resistance to flow, does not reduce the flow area of the wheel and the entire tract.

The water supply to the seal from the bottom up eliminates the ingress of solid particles between the rubbing surfaces.

Under operating conditions of the units, water pressure and generator load fluctuations. To obtain the required generator power, control devices are used that increase or decrease the flow rate of water to the impeller blades.

A known water flow regulator containing balancers, traction and a slider on the shaft of the unit (N. M. Schapov. Turbine equipment of hydroelectric power plants. Moscow, 1961, p. 230, Fig. 14-3). The disadvantages of the analogue are low power and large overall dimensions and weight.

These disadvantages are eliminated in the water flow regulator containing balancers, rods and a slider on the unit shaft, the regulator is closed by a casing, it contains gears with two different gear crowns of different diameters, rotating on axes fixed to the shaft, and gear racks, the larger crown being engaged with a rail fixed on the slider, and a crown of a smaller diameter interacts with the rail connected to the streamlined hollow sealed regulatory body moving along the shaft in the conical part of the water supply pipe.

The design of the regulator is a direct action regulator, but the direct action is not on the drive of the device controlling the flow, but on the water flow itself, which greatly reduces the required force.

To use the centrifugal principle of action of the regulator in a top-down flow of water, the balancers 30 with rods 31 and a slider are enclosed in a casing 29 (FIGS. 1, 13), which protects against the dynamic impact of water on them. The casing is fixedly mounted on the shaft 1 and rotates together with the volume of water in it and the regulator mounted on the shaft in front of the cylindrical axial guide apparatus. The streamlined hollow regulating body 34 is connected by gear racks 33 with gears 36 (FIGS. 15, 16, 17) on axles 37 fixed to the shaft. The gear has two gear rings of different diameters. The axes are placed in the slots of the slider from two opposite sides and are offset by 90 ° relative to the anchorage points of the balancer rods. The regulatory body 34, moving along the shaft in the conical part 15 of the supply pipe 14, changes the cross-sectional area of the flow, i.e. water consumption. With a large diameter, the gear ring engages with the gear racks 35 fixed to the slider, and the crown with a smaller diameter moves the gear racks 33 fixed lower ends to the regulator. Their upper ends are movably fixed in guides on a slider. The regulatory body moves in the opposite direction to the slider. With increasing load on the generator (reducing the speed of rotation of the shaft), the rotating balancers 30 are lowered and through the drive system raise the regulator up the shaft in the conical part 15 of the supply pipe 14, increasing the flow rate of water. Conversely, with an increase in the shaft rotation speed, the regulatory body reduces the water supply to the impeller. The degree of increase in effort from the developed balancers is determined by the ratio R: r (the radius of the larger gear ring gear to the smaller radius). This quality of the regulator allows it to be used for medium and high power turbines. It provides the required turbine power without an intermediate reinforcing means for actuating the regulatory body. The controller contains only the mechanical part without elements of electroautomatics, which will reduce the number of failures and inertia, i.e. increase reliability and simplify maintenance.

Claims (7)

1. The hydraulic unit of a hydroelectric power station, comprising an impeller with a seal and an attached pallet equipped with exhaust pipes, a vertical shaft resting on its lower end against a thrust frame, and a guide apparatus, characterized in that the shaft has a spherical bearing surface, a guide apparatus, and an upper part of the impeller is made in the form of coaxial pipes of the same diameter and installed at a distance of the working gap between them, the impeller seal is located between the casing fixed to the wheel rim and the guide a Paratov, the pallet has a conical shape and the outlet tube are made variable and fixed by the cross-sectional area and are arranged at the bottom of the pallet, the assembly is provided with a water flow regulator. 2. The hydraulic unit according to claim 1, characterized in that the blades of the guide apparatus and the impeller are curved in the opposite direction. 3. A guiding apparatus containing curved blades, characterized in that the blade is fixedly attached at one end to the inner rim and peripheral to the outside and is tangent to the plane of the output section of the apparatus, the blades overlapping its entire cross section in the vertical direction, the upper edge of the blade oriented in a radial plane with an inclination to the outer rim, and the bottom - horizontally. 4. The guiding apparatus according to claim 3, characterized in that the gap between the inner rim and the shaft is sealed with flexible elastic rings — a lower rectangular cross-section, freely rotating on the shaft, and an upper triangular cross-section, mounted with an interference fit on the shaft and pressing the lower to the end rim. 5. The impeller with curved blades fixed to the inner rim of the blades, characterized in that it contains an outer rim made with a cylindrical part at the top and conical below, to which the peripheral ends of the blades are attached with the upper part made vertically to the cylindrical part, and the lower curved to the conical, the upper edge of the blade is radially oriented, and the lower - horizontally. 6. The impeller seal, consisting of two elastic flexible rings with the profile of the trough, the bottom facing up, hermetically fixed on one side to the parts to be sealed, and the opposite convex sides in contact with each other, the reverse surfaces of which are exposed to the working pressure of the water supplied from the bottom up, characterized in that the rings are placed at the same level between the sealed parts, the inner ring being fixed to the sealed part with the side with a smaller diameter. 7. A water flow regulator containing balancers, rods and a slider on the unit shaft, characterized in that it is closed by a casing, contains gears with two different diameter gear rings rotating on axes fixed to the shaft, and gear racks, with a larger diameter crown meshing with a rail fixed to the slider, and a crown of a smaller diameter interacts with the rail connected to the streamlined hollow sealed regulatory body moving along the shaft in the conical part of the water supply pipe.

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