Eddy current inhibition structure of water taking flow channel

Abstract

The invention relates to the technical field of water taking engineering, in particular to a vortex inhibition structure of a water taking runner, which comprises a guide wall and at least two perforated plates, the guide wall is positioned at the downstream of the perforated plates, the perforated plates are positioned at a water inlet, and the perforated plates are arranged at intervals along the water incoming direction; the porosity of the perforated plate is gradually reduced in the water flow direction, the boundary dimension of the perforated plate is matched with the section dimension of the flow channel, the periphery of the perforated plate is connected to the inner wall of the flow channel, the flow guide wall is arranged on a transition section of the flow channel and is in a wave shape, and the thickness direction of the flow guide wall is arranged in the height direction of the flow channel. The wave extending direction of the flow guide wall is arranged in the water flow direction, and the two side walls of the flow guide wall are connected to the two side walls of the transition section. The vortex strength is reduced; the efficiency of the pump station is improved; the potential safety hazard is reduced; and the application prospect is good.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water intake engineering, and particularly relates to a vortex suppression structure of a water intake flow channel. BACKGROUND

[0002] In a coastal power plant water intake engineering, flow channel and pump house vortex (including water surface air suction vortex, wall vortex and through vortex) are core problems threatening water intake safety. Vortex can induce water pump cavitation, unit vibration and flow imbalance, and even cause equipment damage or unplanned shutdown. In the existing flow channel, a vertical guide wall is usually arranged, but when water flow quickly passes through the sharp corner of the wall, a Karman vortex street is easily generated at the corner, inducing low-frequency oscillation, and water flow suddenly enters the narrow pump house inlet from the wide channel, forming an air suction vortex due to flow rate mutation, resulting in pump cavitation. SUMMARY

[0003] The present application aims at solving the problems of the existing vertical guide wall that is easy to generate Karman vortex street and form air suction vortex, and provides a vortex suppression structure of a water intake flow channel.

[0004] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: The present application provides a vortex suppression structure of a water intake flow channel, which comprises a guide wall and at least two porous plates, the guide wall is located downstream of the porous plates, the porous plates are located at the water inlet, the porous plates are arranged at intervals along the water flow direction, the porosity of the porous plates gradually decreases along the water flow direction, the outer dimensions of the porous plates are adapted to the cross-sectional dimensions of the flow channel, the four sides of the porous plates are connected to the inner walls of the flow channel, the guide wall is arranged at the transition section of the flow channel, the guide wall is in a wave shape, the thickness direction of the guide wall is arranged along the height direction of the flow channel, the wave extension direction of the guide wall is arranged along the water flow direction, and the two side walls of the guide wall are connected to the two side walls of the transition section.

[0005] The number, arrangement interval, porosity and through-hole diameter of the porous plates are set according to actual needs and working conditions, the porosity of the porous plates gradually decreases along the water flow direction, that is, the porosity of the porous plates is arranged in a stepped decrease from the side close to the water inlet to the side away from the water inlet; the transition section is located on the upstream side of the trumpet mouth water distribution wall, the thickness direction of the guide wall is arranged along the height direction of the flow channel, the surface of the guide wall plate is arranged horizontally in the flow channel (not limited to be absolutely perpendicular to the side wall of the flow channel), so that the water flow can be divided into upper and lower parts by the guide wall and then enter the trumpet inlet channel formed by the water distribution wall, the upper and lower surfaces of the wave-shaped guide wall both have undulations, the upper and lower surfaces can have the same wave shape or can be different, and the guide wall can be in a wave shape formed by equal thickness or in a wave shape formed by unequal thickness.

[0006] The vortex suppression structure of the water inlet flow channel can be used to arrange the porous plate at the water inlet in the water inlet direction, filter and slow down the water flow, reduce the flow speed, prevent the formation of air suction vortex, slow down the water flow, and further prevent the accumulation at the horn mouth, especially further reduce the accumulation of dead water area when only part of the horn mouth works, the flow guide wall divides the water flow into layers in the transverse direction, effectively prevents the exchange of vertical water flow, destroys the stability of the shear layer of the incoming flow, dissipates the vortex energy in advance, and the vortex cannot fall off synchronously, so that the karman vortex street is difficult to form, the uniformity of the flow speed of the flow channel is significantly improved, the vortex intensity is reduced, the efficiency of the pump station is improved, the safety hidden danger is reduced, and the vortex suppression structure of the water inlet flow channel has good application prospect.

[0007] Preferably, the flow guide wall is in a continuous sinusoidal wave shape, the wavelength L of the sinusoidal wave shape is 3-5 times the design water depth of the flow channel, and the wavelength H of the sinusoidal wave shape is 0.3-0.5 times the design water depth of the flow channel.

[0008] Preferably, the flow guide wall has 1-2.

[0009] Preferably, when the flow guide wall has two, the two flow guide walls are arranged in an up-down distribution.

[0010] Preferably, the shapes and sizes of the two flow guide walls are the same, and the wave crests of the two flow guide walls are arranged in a staggered manner.

[0011] Preferably, the through holes of the porous plate are arranged in an axial downward inclined manner, and the angle between the axial direction of the through hole and the longitudinal direction of the flow channel is 15-20°.

[0012] Preferably, the porous plate is provided with a flow guide wing.

[0013] Preferably, a sand setting area is arranged on the downstream side of the porous plate, the bottom surface of the sand setting area is in a wave shape, and the wave extension direction of the wave shape is arranged along the water flow direction.

[0014] The porous plate can reduce the water flow speed and guide the water flow to sink, form a sand setting area on the downstream side of the porous plate, and have a wave-shaped appearance with the functions of flow stabilization and disturbance, further destroy the residual shear layer, prevent large vortex generation, and make the water flow speed distribution more uniform and the surface fluctuation smaller. Through the preposition of the porous plate, the pulsation is eliminated, the sand setting area can be safely introduced into the controllable disturbance without affecting the sand setting and causing vortex, the porous plate slows down the flow speed and improves the sand setting efficiency, the sand setting area further stabilizes the water flow, suppresses the vortex formation, the flow guide wall further destroys the shear layer, and finally makes the water surface of the horn mouth more stable.

[0015] Preferably, the wave height of the wave shape is 5-6 cm.

[0016] Preferably, the porosity of the porous plate is 40%-60%, and the pore diameter of the porous plate is 50-100 mm.

[0017] Preferably, the plurality of plates are three and are made of aluminum.

[0018] In summary, the beneficial effects of the present application are: 1. The vortex suppression structure of the water intake flow channel is adopted, the plurality of plates are arranged at the water inlet in the water inlet direction, which can form filtering and slow down the water flow rate, avoid sudden change, prevent the formation of air suction vortex, and slow down the water flow, which is also beneficial to sand setting, further prevents the accumulation at the horn mouth, especially further reduces the accumulation of dead water area that may be formed when only part of the horn mouth works, the flow guide wall divides the water flow into layers horizontally, effectively prevents vertical water flow exchange, destroys the stability of the shear layer of the incoming flow, dissipates vortex energy in advance, and the vortex cannot fall off synchronously, which is difficult to form a karman vortex street, the turbulent kinetic energy decay rate of the pump house inlet section is obviously improved, the uniformity of the flow channel flow rate is significantly improved, the vortex intensity is reduced, the pump station efficiency is improved, the safety hidden danger is reduced, and the vortex suppression structure of the water intake flow channel has good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a three-dimensional structure schematic diagram of a vortex suppression structure of a water intake flow channel (not shown flow channel side wall); Figure 2 is a front elevation schematic diagram of a vortex suppression structure of a water intake flow channel; Figure 3 is a top view schematic diagram of a vortex suppression structure of a water intake flow channel; Figure 4 is a schematic diagram of the arrangement structure of the flow guide wall; Figure 5 is a schematic diagram of the arrangement structure of the plurality of plates.

[0020] Reference signs: 01 - water inlet, 02 - horn mouth, 1 - flow guide wall, 2 - plurality of plates, 3 - sand setting area. DETAILED DESCRIPTION

[0021] The present application will be described in detail below with reference to the accompanying drawings.

[0022] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0023] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0024] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but that it can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0025] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0026] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, nine, or even more than nine.

[0027] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0028] Example 1 like Figures 1-5 As shown, the eddy current suppression structure of the water intake channel adopted in this invention includes a guide wall 1, a sedimentation zone 3, and three perforated plates 2. The guide wall 1 is located downstream of the perforated plates 2, and the perforated plates 2 are located at the water inlet 01. The perforated plates 2 are spaced apart along the direction of incoming water, and the porosity of the perforated plates 2 gradually decreases along the direction of water flow. The external dimensions of the perforated plates 2 are adapted to the cross-sectional dimensions of the channel. The four sides of the perforated plates 2 are connected to the inner wall of the channel. The guide wall 1 is located in the transition section of the channel. The guide wall 1 is wavy, and the thickness direction of the guide wall 1 is set along the height direction of the channel. The wave extension direction of the guide wall 1 is arranged along the direction of water flow. The two side walls of the guide wall 1 are connected to the two side walls of the transition section.

[0029] Specifically, such as Figure 1 As shown, the water flow direction is from right to left. The guide wall 1, the sedimentation zone 3, and the perforated plate 2 are located between the inlet 01 and the funnel mouth 02. The perforated plate 2 is located upstream of the sedimentation zone 3 and close to the inlet 01. The sedimentation zone 3 is located upstream of the guide wall 1, and the guide wall 1 is located upstream of the funnel mouth 02. There is a gap between the guide wall 1 and the funnel mouth 02 to avoid forming a sharp bend at the connection. The gap between the two can form a buffer zone to further prevent the generation of vortices and effectively suppress eddies in different zones and grades.

[0030] The perforated plate 2 can be an aluminum plate, and the porosity of the perforated plate 2 is 40%-60%, that is, the upstream perforated plate 2 ( Figure 1 The maximum porosity of the three porous plates is 60% for the rightmost plate and 60% for the most downstream porous plate 2. Figure 1 The maximum porosity of the three perforated plates (leftmost one) is 40%. Specific parameters, variation rates, and arrangement spacing are set according to actual needs. The pore diameter of the perforated plate 2 is 50-100mm. The through-holes of the perforated plate 2 are axially inclined downwards to guide the water flow downwards. The axial direction of the through-holes is parallel to the longitudinal direction of the flow channel. Figure 2 The included angle (in the horizontal direction) is 15-20°. The downstream side of the perforated plate 2 can also be provided with a guide vane. The guide vane is also inclined downward and parallel to the axis of the through hole. The guide vane can be set separately for each row of through holes or for each hole individually.

[0031] The downstream side of the perforated plate 2 is adjacent to the sedimentation zone 3. The bottom surface of the sedimentation zone 3 is wavy. The wave extension direction of the wave surface is set along the water flow direction. The wave height of the wave surface is 5-6cm, and the wavelength is set according to actual needs.

[0032] Downstream of sedimentation zone 3 is the transition section of the flow channel, which has a gradual structure. A guide wall 1 is installed in the transition section. The thickness of the guide wall 1 is set according to actual needs. The guide wall 1 has a continuous sine wave. The wavelength L of the sine wave is 3-5 times the design water depth of the flow channel, and the wavelength H of the sine wave is 0.3-0.5 times the design water depth of the flow channel. The guide wall 1 is roughly located in the middle of the height of the flow channel.

[0033] Using the vortex suppression structure of this embodiment, the flow channel velocity non-uniformity can be reduced from 35% in the traditional design to 12%, the vortex intensity (vortex modulus |ω|) can be reduced by more than 40%, and the turbulent kinetic energy attenuation rate of the pump room inlet section can be increased by up to 2.1 times.

[0034] In some optional embodiments, the number of perforated plates 2 can be 2, 4, etc., and the specific number, plate thickness, and arrangement spacing can be set according to the size of the flow channel, design requirements, etc.

[0035] In some alternative embodiments, the perforated plate 2 may also be a PVC plate, a steel plate, etc.

[0036] In some optional embodiments, there are two guide walls 1, which are arranged vertically, have the same shape and size, and have staggered crests.

[0037] In some alternative embodiments, the flow guide wall 1 may also be a smooth waveform such as a semi-circular wave.

[0038] The vortex suppression structure of the water intake channel described in this invention, with perforated plates spaced at the inlet along the direction of incoming water, can filter and slow down the water flow velocity, gradually reducing the velocity to avoid abrupt changes and prevent the formation of suction vortices. The slowed water flow also facilitates sediment settling, further preventing siltation at the funnel-shaped inlet, especially reducing siltation in dead water zones that may form when only some funnel-shaped inlets are working. The guide wall stratifies the water flow laterally, effectively preventing vertical water flow exchange, disrupting the stability of the incoming flow shear layer, dissipating vortex energy in advance, preventing vortices from falling off synchronously, and making it difficult to form a Karman vortex street. This significantly improves the uniformity of the flow velocity in the channel, reduces vortex intensity, improves pump station efficiency, reduces safety hazards, and has good application prospects.

[0039] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vortex suppression structure for a water intake channel, characterized in that, The system includes a flow guide wall (1) and at least two perforated plates (2). The flow guide wall (1) is located downstream of the perforated plates (2). The perforated plates (2) are located at the inlet (01). The perforated plates (2) are spaced apart along the direction of incoming water. The porosity of the perforated plates (2) gradually decreases along the direction of water flow. The external dimensions of the perforated plates (2) are adapted to the cross-sectional dimensions of the flow channel. The periphery of the perforated plates (2) is connected to the inner wall of the flow channel. The flow guide wall (1) is located in the transition section of the flow channel. The flow guide wall (1) is wavy. The thickness direction of the flow guide wall (1) is set along the height direction of the flow channel. The wave extension direction of the flow guide wall (1) is arranged along the direction of water flow. The two side walls of the flow guide wall (1) are connected to the two side walls of the transition section.

2. The vortex suppression structure of a water intake channel according to claim 1, characterized in that, The guide wall (1) has a continuous sinusoidal waveform, with the wavelength L of the sinusoidal waveform being 3-5 times the design water depth of the channel and the wavelength H of the sinusoidal waveform being 0.3-0.5 times the design water depth of the channel.

3. The vortex suppression structure of a water intake channel according to claim 2, characterized in that, There are 1-2 flow guide walls (1). When there are 2 flow guide walls (1), the two flow guide walls (1) are distributed vertically.

4. The vortex suppression structure of a water intake channel according to claim 3, characterized in that, The two guide walls (1) are identical in shape and size, and the crests of the two guide walls (1) are staggered.

5. A vortex suppression structure for a water intake channel according to any one of claims 1-4, characterized in that, The through holes of the porous plate (2) are inclined downwards, and the angle between the through hole axis and the longitudinal direction of the flow channel is 15-20°.

6. The vortex suppression structure of a water intake channel according to claim 5, characterized in that, The perforated plate (2) is provided with guide vanes.

7. The eddy current suppression structure for a water intake channel according to claim 5, characterized in that, The perforated plate (2) has a sedimentation zone (3) on its downstream side. The bottom surface of the sedimentation zone (3) is wavy, and the wave extension direction of the wavy surface is set along the water flow direction.

8. The vortex suppression structure of a water intake channel according to claim 7, characterized in that, The wave height of the wave surface is 5-6 cm.

9. The vortex suppression structure of a water intake channel according to claim 5, characterized in that, The porosity of the porous plate (2) is 40%-60%, and the pore diameter of the porous plate (2) is 50-100mm.

10. The vortex suppression structure of a water intake channel according to claim 5, characterized in that, There are three perforated plates (2), and the perforated plates (2) are aluminum plates.

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