Arrangement method of V-shaped hollow sill for lateral water distribution pool

Abstract

The invention discloses a V-shaped hollow sill arrangement method for a lateral water distribution pool, which comprises the following steps of: determining the water level and the flow velocity of inlet incoming water, and calculating the Froude number Fr of the inlet; a plurality of incoming flow conditions are simulated through numerical values, and the comprehensive outlet uniformity is calculated according to the lateral diversion outlet section of the water diversion pool; fitting the data scatter curve to obtain a single-peak function curve of the lateral outflow uniformity along with the change of the angle of the diversion side sill under each incoming flow condition, and recording the peak value of the curve; obtaining an exponential growth curve function of a lateral outflow uniformity peak value changing along with Froude number under each incoming flow condition; and obtaining and adjusting the divergence angle of the sill diversion side based on the determined Froude number. The variable-angle V-shaped sill is arranged according to different incoming flow conditions, so that the variable-angle V-shaped sill is suitable for various incoming flow working conditions, the construction cost is reduced, and the hub income of the diversion gate station is improved.

Description

Technical Field

[0001] The invention belongs to the field of flow state improvement of water conservancy projects, and in particular relates to a method for arranging a V-shaped hollow bottom sill for a lateral water diversion pool. Background Art

[0002] The water diversion sluice station hub is a hub project that integrates the water diversion sluice and pump station, which can meet the water inlet demand from multiple directions. The water diversion pool is the core water inlet structure of the water diversion sluice station hub, connecting the upstream tunnel and the downstream sluice station water inlet structure. Under lateral water inlet conditions, centrifugal force will be generated due to the influence of the bend, causing the flow velocity and pressure inside and outside to change. And in this process, the fluid tends to flow to the outer wall due to inertia. This trend further deepens the "wall separation" phenomenon of the water flow, resulting in a significant reduction in the flow section of the front pool, uneven streamline distribution, and the formation of vortices, backflows and other undesirable flow states, which directly affects the safety and efficient operation of the pump station.

[0003] In order to reduce the impact of bad flow patterns in water distribution tanks, domestic and foreign scholars have conducted extensive research on flow pattern improvement. In actual engineering applications, the bottom sill, as a measure to improve flow patterns, can adjust the cross-sectional water flow structure to improve the flow pattern and make the flow velocity in the horizontal and vertical sections evenly distributed. However, the traditional bottom sill layout is related to the body parameters of the bottom sill itself and the flow rate and water level. Under multiple lateral inflow conditions, the effect of improving the flow pattern is average. Summary of the invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the background technology, the present invention discloses a method for arranging a V-shaped hollow bottom sill for a lateral water diversion pool. The method sets a V-shaped bottom sill with a variable angle according to different flow conditions, making it suitable for a variety of flow conditions. It is of great significance to reduce the project cost, increase the hub revenue of the water diversion station and provide a reference for the arrangement of the bottom sill of the water diversion pool.

[0005] Technical solution: The present invention discloses a method for arranging a V-shaped hollow bottom sill for a lateral water diversion pool, comprising the following steps:

[0006] S1. Determine the inlet flow level and flow rate, calculate the inlet Froude number Fr, and use the Froude number Fr to represent the inlet flow situation;

[0007] S2. Through numerical simulation of multiple incoming flow conditions, the comprehensive uniformity of the outlet is calculated according to the lateral diversion outlet section of the water diversion pool to obtain data scatter points;

[0008] S3, fitting the data scatter curve to obtain a single-peak function curve of the lateral outflow uniformity changing with the angle of the bottom sill on the diversion side under each incoming flow condition, and recording the peak value of the curve;

[0009] S4, associating the peak value of the curve with the Froude number Fr of the incoming flow condition, and obtaining an exponential growth curve function of the peak value of the lateral outflow uniformity as the Froude number changes under each incoming flow condition;

[0010] S5. According to the exponential growth curve function in S4, the diffusion angle on the diversion side of the bottom sill is obtained based on the determined Froude number and adjusted.

[0011] Furthermore, S2 simulates the flow pattern of the water flow in the diversion pool with a changing bottom sill angle on the diversion side under multiple incoming flows.

[0012] Furthermore, the uniformity calculation formula in S2 is as follows:

[0013]

[0014] Among them, u ai It is the velocity of the water flow along the mainstream direction at any measuring point on the cross section of the outlet of the lateral diversion section of the diversion tank;

[0015] u ave It is the average velocity of the water flow along the mainstream direction at any measuring point on the cross section of the outlet of the lateral diversion section of the diversion tank;

[0016] n is the number of measuring points.

[0017] Furthermore, the curve function in S4 is as follows:

[0018]

[0019] θ1 is the diffusion angle on the diversion side of the bottom sill.

[0020] Furthermore, the diversion pool includes an upstream culvert section, a diffusion section, a flat end, a lateral diversion section and a forward diversion section through which water flows in sequence; the diffusion section is provided with a first adjustable V-shaped hollow bottom sill and a second adjustable V-shaped hollow bottom sill for rectification.

[0021] Furthermore, the rotation points of the first adjustable V-shaped hollow bottom sill and the second adjustable V-shaped hollow bottom are arranged on the center line of the water diversion pool, the hollow bottom sill structures on both sides of the rotation points are consistent, the first adjustable V-shaped hollow bottom sill is provided with two holes on one side, and the second adjustable V-shaped hollow bottom sill is provided with three holes on one side.

[0022] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0023] The V-shaped top angle can be adjusted according to the flow rate and water level to achieve better flow improvement effect. When there is no lateral diversion in the water diversion pool, the bottom sills on both sides of the variable V-shaped hollow are set to 0°. At this time, the bottom sill can not only distribute the cross-sectional flow velocity well, but also distribute the central water flow to both sides, thus improving the outlet uniformity. When there is lateral diversion on both sides of the water diversion pool, it is necessary to adjust the bottom sill angle on the side with diversion according to the relationship curve between the bottom sill angle and the inlet Froude number, so that the bottom sill rectification effect can be better;

[0024] The V-shaped bottom sill is set inside the diffusion section of the water distribution pool, and the top angle is consistent with the axis of the water distribution pool, which can reduce the impact of backflow in the diffusion section, make the water flow velocity inside the water distribution pool evenly distributed, and the water pump unit can operate more stably;

[0025] Reasonable sill width not only ensures its structural strength, but also reduces the production cost. Reasonable sill height makes the flow diversion effect of the sill more obvious, while also ensuring sufficient flow area and reducing hydraulic loss.

[0026] The hollow bottom sill structure reduces the vertical rolling of the water flow behind the bottom sill, further optimizing the inflow conditions. Ensuring that there are enough hollow parts on the bottom sill can drive more straight water flow, which has a better flow improvement effect on the water flow falling on the bottom sill. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a top view of the water distribution pool of the present invention;

[0028] Figure 2 This is a structural diagram of the first adjustable V-shaped hollow bottom sill of the present invention;

[0029] Figure 3 This is a structural diagram of a second adjustable V-shaped hollow bottom sill of the present invention;

[0030] Figure 4 It is the curve of the comprehensive uniformity of the lateral diversion section under different incoming flow conditions as the angle of one side of the adjustable V-shaped bottom sill changes;

[0031] Figure 5 This is the curve of the change of the angle of one side of the optimal adjustable V-shaped bottom sill with the Froude number. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described below in conjunction with specific implementation methods.

[0033] like Figure 1-3As shown, the diversion pool includes an upstream pipe culvert section 1, a diffusion section 2, a flat end 3, a lateral diversion section 4, and a forward diversion section 5 through which water flows in sequence; the diversion section 2 is provided with a first adjustable V-shaped hollow bottom sill 6 and a second adjustable V-shaped hollow bottom sill 7 for rectification. The rotation points of the first adjustable V-shaped hollow bottom sill 6 and the second adjustable V-shaped hollow bottom sill 7 are both arranged on the center line of the diversion pool, and the hollow bottom sill structures on both sides of the rotation point are consistent, the first adjustable V-shaped hollow bottom sill 6 is provided with two holes on one side, and the second adjustable V-shaped hollow bottom sill 7 is provided with three holes on one side.

[0034] The length L of the diffusion section 2 of the water diversion pool is 50 m, the width B of the starting point of the diffusion section is 5 m, the diffusion angle θ is 22.62°, and the slope i is 0.412%.

[0035] The rotation point of the first adjustable V-shaped hollow bottom sill 6 is arranged on the center line 8 of the water diversion pool, and the length from the rotation point to the starting point of the diffusion section is L1 = 0.3L = 15m. The V-shaped hollow bottom sills on both sides of the rotation point have the same structure, with two holes arranged on one side, the bottom sill length L2 = 5.3m, the bottom sill width B1 = 0.8m, and the bottom sill height H1 = 1m.

[0036] The distance between the center of the first hole of the V-shaped hollow bottom sill on one side of the rotation point and the outside length is L3=1 / 3L2=1.62m, the hole width is B2=0.18B=0.9m, and the hole height is H2=0.6H1=0.6m. The distance between the center of the second hole of the V-shaped hollow bottom sill on one side of the rotation point and the inside length is L4=1 / 3L2=1.62m, the hole width is B3=0.18B=0.9m, and the hole height is H3=0.6H1=0.6m.

[0037] The rotation point of the second adjustable V-shaped hollow bottom sill 7 is arranged on the center line 8 of the water diversion pool, and the length from the rotation point to the starting point of the diffusion section is L5 = 0.7L = 35m. The V-shaped hollow bottom sills on both sides of the rotation point have the same structure, with 3 holes arranged on one side, the bottom sill length L6 = 9.2m, the bottom sill width B4 = 0.8m, and the bottom sill height H4 = 1m.

[0038] The length of the first hole center of the V-shaped hollow bottom sill on one side of the rotation point from the outside is L7=2 / 9L6=2m, the hole width B5=0.24B=1.2m, and the hole height H5=0.6H4=0.6m. The length of the second hole center of the V-shaped hollow bottom sill on one side of the rotation point from the outside is L8=1 / 2L6=4.6m, the hole width B6=0.24B=1.2m, and the hole height H6=0.6H4=0.6m. The length of the third hole center of the V-shaped hollow bottom sill on one side of the rotation point from the inside is L9=2 / 9L6=2m, the hole width B7=0.24B=1.2m, and the hole height H7=0.6H4=0.6m.

[0039] When the bottom sill is laid out, its diffusion angle is determined in the following manner, including the following steps:

[0040] S1. Determine the inlet flow level and flow rate, calculate the inlet Froude number Fr, and use the Froude number Fr to represent the inlet flow situation;

[0041] S2. By numerically simulating the flow pattern of the diversion pool with a different bottom sill angle on the diversion side under multiple incoming flow conditions, the comprehensive uniformity of the outlet is calculated according to the cross-section of the lateral diversion outlet of the diversion pool to obtain data scatter points;

[0042] The uniformity calculation formula is as follows:

[0043]

[0044] Among them, u ai It is the velocity of the water flow along the mainstream direction at any measuring point on the cross section of the outlet of the lateral diversion section of the diversion tank;

[0045] u ave It is the average velocity of the water flow along the mainstream direction at any measuring point on the cross section of the outlet of the lateral diversion section of the diversion tank;

[0046] n is the number of measuring points.

[0047] S3. Fit the data scatter curve to obtain a single-peak function curve of the lateral outflow uniformity changing with the angle of the bottom sill on the diversion side under various inflow conditions, such as Figure 4 As shown, record the peak value of the curve;

[0048] S4. Correlate the peak value of the curve with the Froude number Fr of the incoming flow condition to obtain the exponential growth curve function of the peak value of the lateral outflow uniformity under each incoming flow condition as the Froude number changes, such as Figure 5 As shown;

[0049] The curve function is as follows:

[0050]

[0051] θ1 is the diffusion angle on the diversion side of the bottom sill.

[0052] S5. According to the exponential growth curve function in S4, the diffusion angle on the diversion side of the bottom sill is obtained based on the determined Froude number and a physical adjustment is performed.

[0053] In this embodiment, the inlet boundary flow rate is 23.5m 3 / s, the water level in front of the gate is 530.52m, the β direction diversion gate and the α direction 4-hole diversion gate are opened, and the flow rate of the β direction diversion gate is 14.5m 3 / s.

[0054] The Froude number under this condition is 0.317. From the curve of the Froude number at the inlet of the diffusion section and the optimal angle change of the bottom sill on the left side of the water flow, it can be seen that when the angle of the bottom sill on the left side is adjusted to 8.01°, the comprehensive uniformity of the lateral diversion section is the best.

[0055] Through the middle rotating device of the adjustable V-shaped hollow bottom sill, the right side of the bottom sill is kept fixed and the angle of the left side of the bottom sill is adjusted to 8.01°.

Claims

1. A method for arranging a V-shaped hollow bottom sill for a lateral water diversion pool, characterized in that: The following steps are involved: S1. Determine the inlet flow level and flow rate, calculate the inlet Froude number Fr, and use the Froude number Fr to represent the inlet flow situation; S2. Through numerical simulation of multiple incoming flow conditions, the comprehensive uniformity of the outlet is calculated according to the lateral diversion outlet section of the water diversion pool to obtain data scatter points; S3, fitting the data scatter curve to obtain a single-peak function curve of the lateral outflow uniformity changing with the angle of the bottom sill on the diversion side under each incoming flow condition, and recording the peak value of the curve; S4, associating the curve peak with the Froude number Fr of the incoming flow condition, and obtaining an exponential growth curve function of the lateral outflow uniformity peak value as the Froude number changes under each incoming flow condition; S5. According to the exponential growth curve function in S4, the diffusion angle on the diversion side of the bottom sill is obtained based on the determined Froude number and adjusted.

2. The method for arranging a V-shaped hollow bottom sill for a lateral water diversion pool according to claim 1, characterized in that: S2 simulates the flow pattern of the diversion pool with a changing bottom sill angle on the diversion side under multiple incoming flows.

3. The method for arranging a V-shaped hollow bottom sill for a lateral water diversion pool according to claim 1, characterized in that: The uniformity calculation formula in S2 is as follows: Among them, u ai It is the velocity of the water flow along the mainstream direction at any measuring point on the cross section of the outlet of the lateral diversion section of the diversion tank; u ave It is the average velocity of the water flow along the mainstream direction at any measuring point on the cross section of the outlet of the lateral diversion section of the diversion tank; n is the number of measuring points.

4. The method for arranging a V-shaped hollow bottom sill for a lateral water diversion pool according to claim 1, characterized in that: The curve function in S4 is as follows: θ1 is the diffusion angle on the diversion side of the bottom sill.

5. The method for arranging a V-shaped hollow bottom sill for a lateral water diversion pool according to claim 1, characterized in that: The diversion pool comprises an upstream culvert section (1), a diffusion section (2), a flat end (3), a lateral diversion section (4) and a forward diversion section (5) through which water flows in sequence; the diversion section (2) is provided with a first adjustable V-shaped hollow bottom sill (6) and a second adjustable V-shaped hollow bottom sill (7) for rectifying the flow.

6. The method for arranging a V-shaped hollow bottom sill for a lateral water diversion pool according to claim 5, characterized in that: The rotation points of the first adjustable V-shaped hollow bottom sill (6) and the second adjustable V-shaped hollow bottom sill (7) are both arranged on the center line of the water diversion pool, and the hollow bottom sill structures on both sides of the rotation points are consistent. The first adjustable V-shaped hollow bottom sill (6) is provided with two holes on one side, and the second adjustable V-shaped hollow bottom sill (7) is provided with three holes on one side.

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