Cross-flow hydraulic turbine

Abstract

This utility model pertains to hydraulic engineering, specifically to straight-through hydraulic turbines and a guide vane design for converting water's potential energy into the mechanical energy of a rotating rotor shaft. The technical result of this utility model is smooth adjustment of the guide vane's position with the ability to regulate power and reduce mechanical losses due to the low effort required to rotate the guide vane. The cross-flow hydraulic turbine, in which the guide vane is rotatable to regulate water flow, comprises a cylindrical steel segment and two side support plates through which the cylindrical segment is connected to the rotor axis. The mechanism for rotating the cylindrical steel segment to regulate water flow is located on the outer surface of the side support plates, reducing the effort required to rotate the guide vane.

Description

[0001] The utility model relates to the field of hydraulic engineering, namely, to cross-flow hydraulic turbines for converting the potential energy of water into the mechanical energy of a rotating rotor shaft.

[0002] In hydraulic turbines, the flow generated by the guide vane is determined by the position of the guide vane surface within the flow, specifically its distance from the turbine axis and the inclination of individual elements relative to the axis. It is known that a guide vane inclined relative to the turbine axis cannot have a cylindrical or conical surface. However, the latter is achieved in a so-called conical guide vane, whose blades rotate around a generatrix lying in the meridional plane of the turbine. This design deviation from the requirements of hydrodynamics is necessitated by the need for tight closure of the guide vane, which is most easily achieved using straight-edged blades whose extensions intersect the turbine axis at a single point.

[0003] From the prior art (SU No. 33016 for the invention “Hydraulic turbine for a downstream flow” with the publication date of October 31, 1933), a hydraulic turbine for a downstream flow is known, in which the blades of its guide apparatus are limited by a ruled surface, the guides for which are three arbitrarily taken sections of the blade, perpendicular to the axis of the turbine, selected by shape in accordance with the nature of the free flow and each lower lying one offset in relation to the adjacent upper one by one or another angle by rotation around the axis of the turbine in the direction of its rotation.

[0004] A guide vane for hydraulic turbines is known, containing rotating blades equipped with trunnions of two profiles of different curvatures: in the open part of the chamber - convexity towards the axis of the turbine shaft, and in the spiral part - in the opposite direction (Kovalev N.N. "Hydroturbines", 1961, p. 187). In this guide vane with different blade profiles on a single turbine, a tight fit of the blades to each other in the closed position is not ensured, which leads to a decrease in the energy and dynamic properties of the hydraulic machines.

[0005] A known axial Kaplan turbine comprises a guide vane, the blades of which are curved and rotated in the direction of rotation of the impeller, secured so as to be able to rotate; an impeller located in a chamber with curved blades secured to a housing mounted on a shaft; and water supply and water drainage parts. The guide vane is formed from upper and lower rings with blades arranged between them, mounted so as to be able to rotate using a rotation mechanism consisting of clevises connected to the blades, levers, and an adjusting ring connected to servomotors. The blades are secured to the impeller housing so as to be able to rotate using a rotation mechanism consisting of thrust rings rigidly secured to the blades and pivotally connected to clevises connected to a crosspiece of the impeller, which is connected to a servomotor.The mechanisms for rotating the guide vane blades and the impeller blades are connected by a kinematic linkage and ensure simultaneous position changes. The shaft is positioned vertically relative to the impeller's plane of rotation, and the water-inlet section is designed as a spiral chamber (Smirnov, I.N. Hydraulic Turbines and Pumps. A Textbook for Power Engineering and Polytechnic Universities. Moscow: Higher School, 1969. Page 36).

[0006] The disadvantages of the described hydraulic turbine are the complexity of the design due to the use of mechanisms for turning the guide vane blades and the impeller blades.

[0007] An axial propeller hydraulic turbine is known, comprising a guide vane, the blades of which, made in a curved shape and deployed in the direction of rotation of the impeller, are fixed so as to be able to rotate, an impeller, located in a chamber, with curved blades fixed on a casing mounted on a shaft, water supply and water drainage parts. In this case, the guide vane is made of upper and lower rings with blades located between them, mounted so as to be able to rotate with the help of a rotation mechanism made of shackles connected to the blades, levers and an adjusting ring connected to servomotors. The shaft is located vertically relative to the plane of rotation of the impeller (Smirnov I.N. Hydraulic turbines and pumps. Study guide for power and polytechnic universities. - M.: Higher school, 1969. - P. 35).

[0008] A known axial hydraulic turbine, as described in Russian Patent No. 2371602, comprises a guide vane whose curved blades are oriented in the direction of the impeller's rotation and are mounted so as to rotate. The guide vane itself is comprised of coaxially arranged outer and inner casings and blades, each secured at one end to the inner casing and connected to the outer casing by threaded connections. The blades can rotate from -20° to 20° from the design angle of the guide vane's blades.The impeller chamber is connected at one end to the water-discharging part, and at the other end to the outer casing of the guide apparatus, connected to the curved water-supply part, and the impeller casing is connected to the inner casing of the guide apparatus, mounted on the shaft, wherein the shaft is located horizontally relative to the plane of rotation of the impeller, placed by means of bearing assemblies on supports fixed in the frame, and has the possibility of connection to an asynchronous motor.

[0009] The disadvantages of this type of turbine guide vane control device include difficulty in regulating output power when energy consumption or water pressure changes, as manual blade rotation is required. The unit's operational capabilities are limited due to the guide vane blade rotation limit of up to 20%. Manufacturing is also labor-intensive due to the use of large and metal-intensive blade mounting assemblies in the bearing housing of the turbine shaft and impeller. Due to the small blade area of ​​the guide vane, the flow becomes turbulent, reducing the unit's output power and causing blade cavitation.

[0010] Russian patent 169404, published March 16, 2017, discloses a utility model, "Adjusting Blade Device for an Axial Turbine," related to hydropower engineering. It can be used to automatically regulate the output power of a hydroturbine by varying the total water flow volume and its angle of incidence on the axial turbine blades through rotating the device's blades. The technical result is to automatically adjust the volume and angle of incidence of the flow passing through the turbine blades. The adjusting blade device, installed upstream of the axial turbine, consists of a cylindrical housing with a streamlined hexagonal bushing and rotating blades within.The blades have the shape of a truncated sector, are fixed and rotate on axes inserted at one end into the center of the faces of the sleeve, and at the other end pass through the wall of the housing to the outside, where gears are fixed to them, connected to a toothed ring, which rotates the axes with the blades of the device, thereby changing the volume and direction of the flow passing through it.

[0011] According to the utility model, axes extend through the cylindrical housing to the center of the faces, and rotating blades in the shape of a truncated sector of a circle are attached to them. In the closed position, one side of each blade overlaps the adjacent radial side of the adjacent blade by 10-15%. The inner ends of the axes rotate in the center of the hub faces, and gears are attached to the axes on the outside of the housing for rotating the blades by an angle of up to 180 degrees, or for fixing them in the required position using a control gear ring installed around the housing. The control gear ring is rotated by the actuator of the hydraulic turbine's automatic power regulation mechanism and synchronously rotates the blades via the gears to the required angle, resulting in changes in the volume of the passing working flow and its angle of incidence on the fixed turbine blades. The control ring is pressed against each rotation gear by the control gear of the power regulator to prevent disengagement of the rotation mechanism.

[0012] Patent CN 108730099, published March 23, 2021, discloses a water turbine guide vane arrangement and a water turbine with the same arrangement. The water turbine guide vane arrangement rotates around an axis and includes a guide vane for deflecting the feed water flow toward the downstream side. The guide vane has a lower end edge including upper and lower end portions, wherein the lower end portion of the lower end edge is offset in a direction perpendicular to the axis relative to the upper end portion of the lower end edge when viewed from the flow side, the distance between the lower end edge and the impeller of the water turbine is increased in the intermediate region between the lower and upper end portions of the lower end edge, and the lower end edge has an S-shaped curve when viewed from the flow side.

[0013] Furthermore, the first rotary shaft may be located at the upper end of the guide vane through a first flange, and the second rotary shaft may be located at the lower end of the guide vane through a second flange. The central axis of each of the first and second rotary shafts coincides with the axis. The bending line of the guide vane is located closer to the pressure surface side of the guide vane than the axis.

[0014] The water turbine is provided with: a box-shaped casing; an impeller rotating under the action of the water flow supplied through the casing; and a device with guide vanes located between the impeller and the casing.

[0015] The water turbine is equipped with: an impeller rotating under the action of the water flow supplied through the casing; and a guide vane located on the outer peripheral side of the impeller, wherein the impeller has a blade having a front end edge with upper and lower end portions, wherein the lower end portion of the front end edge is offset in one direction along the circumference of the impeller relative to the upper end portion of the front end edge, the guide vane has a rear end edge with upper and lower end portions, wherein the lower end portion of the rear end edge is offset in another direction along the circumference of the impeller relative to the upper end portion of the rear end edge, the distance between the rear end edge and the impeller is increased in the middle region between the lower and upper end portions of the rear end edge, and the rear end edge has an S-shape when viewed from the side facing the flow.

[0016] A water turbine further comprising: and a fixed blade located on the outer peripheral side of the guide blade, wherein the fixed blade has a lower end edge having upper and lower end portions, wherein the lower end portion of the lower end edge of the fixed blade is displaced in a direction identical to the displacement of the lower end portion of the lower end edge of the guide blade relative to the upper end portion of the lower end edge of the guide blade when viewed from the side facing the flow.

[0017] Each guide vane has a lower end edge that is parallel to the axis of rotation of the impeller.

[0018] The impeller comprises a plurality of impeller blades arranged at equal intervals in the circumferential direction. The lower end of the upper edge of each impeller blade is offset from its upper end in the circumferential direction of the impeller.

[0019] From JPH 10318117 patent, published on December 2, 1998, a hydraulic equipment impeller is known. The leading edge of the impeller blade on the working fluid inlet side in a Francis-type water turbine, in which a plurality of impeller blades are arranged in a row circumferentially between the crown and the casing, when the turbine operates as a water turbine. In a Kaplan-type water turbine, in which a plurality of impeller blades are radially arranged around the hub, a movable impeller blade is provided at the root on the hub side, on the leading edge on the working fluid inlet side, and at the end on the casing side. An impeller for a hydraulic machine, in which the impeller has an angle of attack substantially equal to the angle of incidence of the working fluid in the operating state, and has a conical protrusion with an acute angle of retreat.

[0020] A known design of a double-flow turbine comprises a water supply, a rotor with blades made in the form of cylindrical shells, and a guide vane (D.Ya. Sokolov. Use of Water Energy. Moscow: Selkhozgiz, 1953, p. 49, Fig. 43-6). The latter is a nozzle formed by flat surfaces with a rectangular cross-section, providing a simultaneous water supply to approximately 10-15% of the blades of the rotor, and water flow regulation is carried out using a flat shield.

[0021] A double-flow hydroturbine design developed by the German company Ossberger is also known, a general description of which is given in US Patent 4579506A, IPC 7 F01D 1 / 12 dated April 1, 1986. The design comprises a water inlet and a rotor wheel with blades made in the form of cylindrical shells. The profiled water inlet is designed as a prechamber, with an angle of coverage of the rotor blades by the pressure front, which is larger compared to the previously mentioned analogue. The prechamber contains a device made in the form of a rotating wing with a profiled cross-section, which serves to partially regulate the water flow through the turbine. The greater number of blades simultaneously involved in the working process, the configuration of the water inlet profile, and the wing located in the prechamber made it possible to increase the turbine's power and raise its efficiency to approximately 84%.

[0022] The disadvantage of this design is the lack of the ability to regulate the water flow through the turbine from zero to the maximum value using a rotary wing.

[0023] The guide vane consists of flat blades set at an angle of 4-12° to the tangent circle forming the blade at its leading edge, ensuring optimal flow entry conditions onto the impeller blades. The water flow control device, located between the guide vanes and the impeller blades, is a cylindrical segmented valve whose axis of rotation is aligned with the impeller's axis of rotation. This device regulates the water flow through the turbine from zero to its maximum value using a drive located on one of the side walls of the prechamber.

[0024] The impeller contains disks and blades mounted on them, formed as cylindrical shells. The configuration of the interblade channels, formed by the radius of curvature of the blades, their number, and arrangement, ensures optimal fluid flow conditions through the impeller from an energy perspective. Bearing assemblies are located on the side walls of the prechamber, housing the impeller shaft journals. The maximum efficiency of the hydroturbine is approximately 90%.

[0025] The invention “The device is intended for converting the energy of a water flow into mechanical work” is known under the Russian Federation patent 2221163 with the publication date of 01 / 10 / 2004.

[0026] The turbine contains a water supply, a guide vane, a water flow control device and an impeller, the blades of which are made in the form of cylindrical shells fixed on disks.

[0027] The guide vane is made in the form of flat blades installed at an angle of 4-12° to the tangent circle forming the blade, at the location of its leading edge. The water flow control device is equipped with a drive that ensures this flow rate from zero to a maximum value. A double-stage hydraulic turbine comprises a water supply, a guide vane, a water flow control device, and an impeller, the blades of which are designed as cylindrical shells fixed on disks. The guide vane is made in the form of flat blades installed at an angle of 4-12° to the tangent circle forming the blade, at the location of its leading edge, and the turbine is equipped with a device for regulating the water flow from zero to a maximum value, equipped with a drive.The technical result is achieved by introducing a guide vane into the turbine design to create optimal conditions for water flow to the impeller blades and by using a cylindrical segment gate as a device for regulating water flow through the turbine, which allows for regulating the water flow from zero to a maximum value and does not disturb the structure of the flow at any position in the flow path.

[0028] The invention "Compact River Hydroturbine" is known under patent application 2019117727, published on December 7, 2020, for generating electricity by passing a fluid flow through the working section. The power plant consists of a variable-geometry frame, including two guide vanes connected at the top and bottom by two fixing plates, two low-frequency generators located on the lower and upper fixing plates, and a rotor consisting of three vertically arranged blades, interconnected by pylons and rotating around a common axis, transmitting torque to the axis of the electric generator. The connecting pylons of the blades directly serve as the rotation shafts of the hydroturbine rotor. Furthermore, the hydroturbine can be designed to change the position of the guide vanes of the power plant frame.Rotor blades can have a three-dimensional wave profile of variable cross-section, providing higher hydrodynamic quality compared to blades of constant cross-section.

[0029] The closest technical solution is the "Hydroturbine" invention, according to Russian Patent 2806776, published on March 17, 2023. It is characterized by a water inlet, a turbine base, a guide vane, a drive, and a rotor wheel, the blades of which are mounted on disks. The guide vane is made of an external support with a curved surface, enveloping the rotor wheel on the water inlet side. The lower end of the support is equipped with a hinge located on the base. The middle section of the support is connected to the drive, also located on the base, via other hinges and a rod. The rotor wheel blades have a bucket-shaped profile.

[0030] The disadvantages of the prototype include the complexity of the shape of the blade rotating around the axis, and the control of the position of the guide vane is carried out by rotating the axis.

[0031] The technical objective of the claimed utility model is to propose a structurally simple and effective guide apparatus for regulating the flow of water with improved energy and operational characteristics.

[0032] The technical result of the utility model is to ensure the possibility of smooth regulation of the position of the guide vane to regulate power and reduce mechanical losses due to small efforts to rotate the guide vane.

[0033] The technical result is achieved through the use of a cross-flow hydraulic turbine, in which the guide vane is designed to rotate to regulate the water flow. It consists of a cylindrical steel segment and two side support plates through which the cylindrical segment is connected to the rotor axis. The mechanism for rotating the cylindrical steel segment to regulate the water flow is located on the outer surface of the side support plates, reducing the effort required to rotate the guide vane.

[0034] The outer cylindrical steel segment can be characterized by constant thickness.

[0035] The turbine is made of carbon, corrosion-resistant steel.

[0036] The figure shows the structure of the guide vane of a cross-flow hydraulic turbine.

[0037] The cross-flow hydraulic turbine consists of a casing 1, a frame 2, a suction pipe 3 and a discharge pipe 4, a rotor 5 with installed blades, and a guide vane 6 with a control system. The guide vane 6 is a cylindrical steel segment and two lateral support plates through which the cylindrical segment is connected to the rotor axis 5.

[0038] The working process in a hydro turbine is as follows.

[0039] The water flow through suction pipe 3 enters casing 1 of the hydroturbine and hits the blades of rotor 5. The water hits the blades twice: when entering rotor 5 and when exiting rotor 5. The water then exits casing 1 through suction pipe 4 or as a free flow downward. The direction and volume of incoming water are regulated by guide vane 6, a cylindrical steel segment connected to the impeller axis by two lateral support plates. The control system rotates guide vane 6 around its axis of rotation, thereby smoothly adjusting the water flow into casing 1 of the hydroturbine. The force from the water flow is applied not to the axis, but to the outer surface of the segment.

[0040] Thus, the guide vane 6 in the form of a cylindrical steel segment connected to the axis of the rotor impeller 5 by two side support plates forms an optimally organized, from an energy point of view, water flow, which, interacting with the impeller blades, ensures high energy characteristics of the hydraulic turbine and allows for smooth and highly accurate regulation of the water flow.

[0041] Since the water flow only flows around the outer cylindrical steel segment of guide vane 6 on one side, the outer side, it can have a constant thickness. However, the segment's thickness depends only on the mechanical loads imposed by the water flow. Manufacturing the outer cylindrical steel segment from a steel sheet of constant thickness simplifies the guide vane design.

Claims

1. A cross-flow hydraulic turbine, characterized in that the guide vane is rotatable to regulate the flow of water and is a cylindrical steel segment and two side support plates through which the cylindrical segment is connected to the rotor axis, wherein the mechanism for rotating the cylindrical steel segment is located on the outer surface of the side support plates.

2. A cross-flow hydraulic turbine according to claim 1, characterized in that the outer cylindrical steel segment has a constant thickness.

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