A calculation method for flow rate of plane arc double-opening gate

Abstract

This invention discloses a method for calculating the flow rate of a planar arc-shaped double-opening gate, belonging to the technical field of water conservancy engineering. The steps are as follows: (1) Collect basic data; (2) Determine basic parameters based on the basic data; (3) Calculate the total head above the gate and the water depth below the gate based on the basic parameters; (4) Calculate the comprehensive flow rate of the planar arc-shaped double-opening gate based on the calculation results; (6) Establish the basic relationship formula for the flow rate of the planar arc-shaped double-opening gate based on the comprehensive flow rate coefficient and lateral contraction coefficient of the flow rate; (7) Obtain the flow rate Q based on the obtained basic relationship formula. The method for calculating the flow rate of a planar arc-shaped double-opening gate of this invention can quickly and accurately calculate the flow rate value of the planar arc-shaped double-opening gate, providing technical support for river flood control.

Description

Technical Field

[0001] The present invention is directed to an engineering calculation method for flow through an arc gate, and in particular relates to a calculation method for flow through a plane arc double-opening gate. Background Art

[0002] The plane arc double-opening gate can meet the comprehensive needs of flood control, tide blocking, drainage and navigation at the same time, and has been applied to water conservancy projects at home and abroad. However, as a new type of gate, the flow of the plane arc double-opening gate is very different from that of the traditional flat-bottom gate, and the factors affecting the flow of the plane arc double-opening gate are more complicated. The existing traditional flat-bottom gate flow calculation method cannot be applied to the plane arc double-opening gate, and there is currently no mature and accurate method for calculating the flow of the plane arc double-opening gate.

[0003] The flow of flat-bottom gates includes weir flow and hole flow (the upstream and downstream water surface lines of weir flow are smooth descending curves, while the upstream and downstream water surface lines of hole flow are discontinuous). The flow of plane arc double-open gates belongs to a type of flat-bottom gate weir flow. However, the existing calculation method of flat-bottom gate weir flow is only applicable to the traditional plane gate with a flat water retaining surface, and is not applicable to the plane arc double-open gate with an arc water retaining surface. This is because the flow state of the plane arc double-open gate with an arc water retaining surface is very different from that of the traditional plane gate with a flat water retaining surface, and the factors affecting the flow rate of the plane arc double-open gate are more complex, resulting in a large difference between the comprehensive flow coefficient and the lateral contraction coefficient of the plane arc double-open gate with an arc water retaining surface and the existing method. According to the actual test results of the physical model test, the experimental measured value of the flow rate of the plane arc double-open gate is quite different from the calculated value of the existing method, and the existing method is difficult to accurately calculate the flow rate of the plane arc double-open gate.

[0004] CN114896566A An intelligent and efficient method for calculating gate flow rate requires collecting a large amount of actual gate operation monitoring data and establishing a neural network calculation model to calculate the gate flow rate. The cost of collecting gate operation monitoring data is relatively high and very time-consuming. The gate needs to be built and operated for a long time, and monitoring equipment needs to be installed to obtain operation monitoring data. The whole process is very complicated. Summary of the invention

[0005] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a method for calculating the flow rate of a plane arc double-opening gate, which can quickly and accurately calculate the flow rate value of the plane arc double-opening gate, providing technical support for river flood control.

[0006] Technical solution: To solve the above technical problems, a method for calculating the flow rate of a planar arc double-opening gate is provided in the present invention, and the steps are as follows:

[0007] (1) Collect the topographic data of the upstream and downstream of the river where the flow rate of the planar arc double-opening gate needs to be calculated, the planar and cross-sectional structure data of the arc double-opening gate, and the basic data of the upstream and downstream water levels;

[0008] (2) Determine the width of the upstream river based on basic data bs , upstream river flow section, gate upper bottom plate elevation D1, gate lower bottom plate elevation D2, gate opening range, upstream and downstream water level range basic parameters;

[0009] (3) Based on the elevation of the upper bottom plate of the gate D1, the elevation of the lower bottom plate of the gate D2, and the upstream water level S1 and downstream water level S2 to be calculated, the total head above the gate and the water depth below the gate are calculated as follows:

[0010] (1)

[0011] (2)

[0012] (3)

[0013] Where: H The water depth above the gate with the upper bottom plate of the gate as the base, in meters; H 0 is the total water head on the gate, in meters; h s The water depth below the sluice gate is based on the bottom plate below the sluice gate, in meters; v 0 is the upstream flow velocity, , unit: m / s; g is the acceleration due to gravity, in meters per second 2 ; Q is the flow rate of the plane arc double-opening gate, in meters 3 / Second, A For the upper reaches of the river S 1 The cross-sectional area under the water level, in meters 2 ;

[0014] (4) Based on the total water head on the gate H 0 and water depth below the sluice gate h s The calculation results show that based on the test results of the hydraulic physical model of the plane arc double-opening gate, the comprehensive flow coefficient is proposed, and its calculation method is fitted to obtain the comprehensive flow coefficient of the plane arc double-opening gate:

[0015] (4)

[0016] Where: m is the comprehensive flow coefficient of the plane arc double-opening gate;

[0017] (5) According to the upstream river width and the gate opening to be calculated, the lateral contraction coefficient is proposed based on the test results of the hydraulic physical model of the plane arc double-opening gate, and its calculation method is fitted to obtain the lateral contraction coefficient of the plane arc double-opening gate flow:

[0018] (5)

[0019] Where: is the side contraction coefficient of the flow of the plane arc double-opening gate; b s is the upstream river width, in meters; b is the gate opening, in meters.

[0020] (6) Based on the comprehensive flow coefficient and lateral contraction coefficient of the plane arc double-opening gate, the basic relationship between the flow rate of the plane arc double-opening gate is established:

[0021] (6)

[0022] Where: Q It is the flow rate of the flat arc double-opening gate.

[0023] (7) From equation (6), equation (2) and equation (4), we can deduce:

[0024] (7)

[0025] The flow Q can be obtained.

[0026] Preferably, the method for calculating the comprehensive flow coefficient in step (4) comprises the following steps:

[0027] (41) Without considering the lateral contraction coefficient of the plane arc double-opening gate flow, the comprehensive flow coefficient is established based on the test results of a series of working conditions with different head differences above and below the gate under different gate openings obtained in the hydraulic physical model test of the plane arc double-opening gate. Relative head difference between above and below the gate The relationship results:

[0028] (8)

[0029] Where: is the test result of the comprehensive flow coefficient of the i-th group of working conditions, is the flow test result of the plane arc double-opening gate under the i-th working condition, is the plane arc double-opening gate opening of the i-th group of working conditions, is the total water head on the gate under the i-th group of working conditions; is the water head under the gate under the i-th group of working conditions; is the comprehensive flow coefficient of the i-th group of working conditions Relative head difference between above and below the gate The corresponding relationship;

[0030] (42) Analysis of comprehensive flow coefficient m The relative head difference between the upper and lower parts of the gate The changing trend of m and The formula form is:

[0031] (9)

[0032] Where: and is the coefficient to be determined;

[0033] (43) Transforming equation (9) using a logarithmic function, we can obtain:

[0034] (10)

[0035] (44) Based on the comprehensive flow coefficient m Relative head difference between above and below the gate The experimental results of the relationship are shown in equation (8). Using the univariate linear regression analysis model, the coefficients in equation (10) are obtained. and , and then determine the comprehensive flow coefficient of the plane arc double-opening gate m .

[0036] Preferably, the method for calculating the side contraction coefficient of the flow of the planar arc double-opening gate in step (5) comprises the following steps:

[0037] (51) Based on the test results of a series of operating conditions under different gate openings obtained in the hydraulic physical model test of the plane arc double-opening gate, the lateral contraction coefficient is established. Relative opening of gate The relationship results:

[0038] (11)

[0039] Where: is the test result of the side shrinkage coefficient of the jth group of working conditions, is the flow test result of the plane arc double-opening gate under the jth group of working conditions, is the calculation result of the comprehensive flow coefficient formula (4) for the jth group of working conditions, is the plane arc double-opening gate opening of the jth group of working conditions, is the total water head on the gate under the jth group of working conditions; b s is the upstream river width; is the lateral contraction coefficient of the jth group of working conditions Relative opening of gate The corresponding relationship;

[0040] (52) Analysis of side shrinkage coefficient With the relative opening of the gate The changing trend of and The formula form is: (12)

[0041] Where: , and is the coefficient to be determined;

[0042] (53) Based on the lateral contraction coefficient With the relative opening of the gate The experimental results of the relationship are analyzed by using a quadratic polynomial regression model, and the coefficients in formula (12) are obtained as follows: , and , and then determine the lateral contraction coefficient of the plane arc double-opening gate .

[0043] Preferably, in step (7), formula (7) is solved by an iterative method, and the right side of formula (7) is defined as Q= Q i 、Formula (7) Left Q=Q i+1 , repeat the iterative calculation process several times, when the relative error When the flow rate of the plane arc double-open gate is taken Q=Q i+1 .

[0044] Beneficial effect: The method for calculating the flow rate of the plane arc double-opening gate of the present invention only needs to know the basic information of the plane arc double-opening gate and the river channel, the gate opening, the upstream and downstream water levels and other information, so as to quickly and accurately calculate the flow rate value of the plane arc double-opening gate, which can provide technical support for river flood control. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the process of the present invention.

[0046] Figure 2 It is a schematic diagram of the current cross section.

[0047] Figure 3 This is a schematic diagram of a flat arc double-opening gate. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with the accompanying drawings.

[0049] like Figures 1 to 3 As shown, a method for calculating the flow rate of a planar arc double-opening gate of the present invention comprises the following steps:

[0050] (1) Collect the upstream and downstream topographic data of the river where the flow rate of the planar arc double-opening gate needs to be calculated, the plan and cross-sectional structure data of the arc double-opening gate, and the basic data of the upstream and downstream water levels.

[0051] (2) Determine the width of the upstream river based on basic data bs= 132m, elevation of the upper bottom plate of the gate D1 = -2.00m, elevation of the bottom plate below the gate D2 = -2.00m, gate opening range is 0~90m, upstream and downstream water level range is 2.00~3.75m.

[0052] (3) Based on the gate bottom plate elevation D1 = -2.00m, elevation of the bottom plate below the gate D2 = -2.00m, and the upstream water level to be calculated is S1 = 3.35m (the cross-sectional area of ​​the upstream river channel at this water level is 684.8m 2 ), downstream water level is S2 = 2.95m, calculate the total head above the gate and the water depth below the gate as follows ( Q i To calculate the flow rate:

[0053] (1)

[0054] (2)

[0055] (3)

[0056] (4) Based on the total water head on the gate H 0 and water depth below the sluice gate h s Calculation results show that the comprehensive flow coefficient of the plane arc double-opening gate is m .

[0057] (5) Based on the width of the upstream river b s = 132m and the gate opening to be calculated b= 55m, the lateral contraction coefficient of the plane arc double-opening gate flow is calculated .

[0058] (6) Using the above parameter results, equation (7) is solved. The iterative calculation process is as follows: the flow rate of the plane arc double-opening gate under this condition is Q =575 m 3 / s.

[0059]

[0060] Note: Using conventional calculation method, the calculated flow rate is about 575 m 3 / s, the measured flow rate is 597 m 3 / s, the relative error between the calculated value and the measured value is less than 5%. It can be seen that the calculation method of the present invention can accurately calculate the flow rate value of the plane arc double-opening gate, which is closer to the actual situation and has good calculation accuracy.

[0061] It can be seen that the method for calculating the flow rate of the plane arc double-opening gate proposed in the present invention can quickly and accurately calculate the flow rate value of the plane arc double-opening gate, which can provide technical support for river flood control.

[0062] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for calculating the flow rate of a plane arc double-opening gate, characterized in that: The following steps are involved: (1) Collect the topographic data of the upstream and downstream of the river where the flow rate of the planar arc double-opening gate needs to be calculated, the planar and cross-sectional structure data of the arc double-opening gate, and the basic data of the upstream and downstream water levels; (2) Determine the width of the upstream river based on basic data bs , upstream river flow section, gate upper bottom plate elevation D1, gate lower bottom plate elevation D2, gate opening range, upstream and downstream water level range basic parameters; (3) Based on the elevation of the upper bottom plate of the gate D1, the elevation of the lower bottom plate of the gate D2, and the upstream water level S1 and downstream water level S2 to be calculated, the total head above the gate and the water depth below the gate are calculated as follows: （a1） （a2） （a3） Where: H The water depth above the gate based on the gate upper bottom plate, in meters; H 0 is the total water head on the gate, in meters; h s The water depth below the sluice gate is based on the bottom plate below the sluice gate, in meters; v 0 is the upstream flow velocity, , unit: m / s; g is the acceleration due to gravity, in meters per second 2 ; Q is the flow rate of the plane arc double-opening gate, in meters 3 / Second, A For the upper reaches of the river S 1 The cross-sectional area under the water level, in meters 2 ; (4) Based on the total water head on the gate H 0 and water depth below the sluice gate h s The calculation results show that the comprehensive flow coefficient is proposed based on the test results of the hydraulic physical model of the plane arc double-opening gate, and its calculation method is fitted to obtain the comprehensive flow coefficient of the plane arc double-opening gate: （a4） Where: m is the comprehensive flow coefficient of the plane arc double-opening gate; (5) According to the upstream river width and the gate opening to be calculated, the lateral contraction coefficient is proposed based on the test results of the hydraulic physical model of the plane arc double-opening gate, and its calculation method is fitted to obtain the lateral contraction coefficient of the plane arc double-opening gate flow: （a5） Where: is the side contraction coefficient of the flow of the plane arc double-opening gate; b s is the upstream river width, in meters; b is the gate opening, in meters; (6) Based on the comprehensive flow coefficient and lateral contraction coefficient of the plane arc double-opening gate, the basic relationship between the flow rate of the plane arc double-opening gate is established: （a6）； (7) From equation (a6), equation (a2) and equation (a4), we can deduce: （a7） The flow Q can be obtained.

2. The method for calculating the flow rate of a planar arc double-opening gate according to claim 1 is characterized in that: The method for calculating the comprehensive flow coefficient in step (4) comprises the following steps: (41) Without considering the lateral contraction coefficient of the plane arc double-opening gate flow, the comprehensive flow coefficient m and the relative head difference above and below the gate are established based on the test results of a series of working conditions with different gate openings and different head differences above and below the gate obtained in the hydraulic physical model test of the plane arc double-opening gate. The relationship results: （a8） Where: m i is the comprehensive flow coefficient test result of the i-th group of working conditions, Q si is the flow test result of the plane arc double-opening gate under the i-th working condition, b i is the plane arc double-opening gate opening of the i-th group of working conditions, H 0i is the total water head on the gate under the i-th group of working conditions; h si is the water head under the gate under the i-th group of working conditions; f i is the comprehensive flow coefficient of the i-th group of working conditions Relative head difference between above and below the gate The corresponding relationship; (42) Analysis of comprehensive flow coefficient m The relative head difference between the upper and lower parts of the gate The changing trend of m and The formula form is: （a9） Where: is the coefficient to be determined; (43) Transforming equation (a9) using a logarithmic function yields: （a10） (44) Based on the comprehensive flow coefficient m Relative head difference between above and below the gate The experimental result of the relationship is formula (a8), and the coefficients in formula (a10) are obtained by using a univariate linear regression analysis model. , and then determine the comprehensive flow coefficient of the plane arc double-opening gate m .

3. The method for calculating the flow rate of a planar arc double-opening gate according to claim 1 is characterized in that: The method for calculating the side contraction coefficient of the flow of the planar arc double-opening gate in step (5) comprises the following steps: (51) Based on the test results of a series of operating conditions under different gate openings obtained in the hydraulic physical model test of the plane arc double-opening gate, the relationship between the lateral contraction coefficient and the relative gate opening is established: （a11） Where: is the test result of the side shrinkage coefficient of the jth group of working conditions, is the flow test result of the plane arc double-opening gate under the jth group of working conditions, is the calculation result of the comprehensive flow coefficient formula (a4) for the jth group of working conditions, b j is the plane arc double-opening gate opening of the jth group of working conditions, is the total water head on the gate under the jth group of working conditions; b s is the upstream river width; is the lateral contraction coefficient of the jth group of working conditions Relative opening of gate The corresponding relationship; (52) Analyze the changing trend of the lateral contraction coefficient with the relative opening of the gate and establish and The formula form is: （a12） In the formula is the coefficient to be determined; (53) Based on the lateral contraction coefficient With the relative opening of the gate The experimental results of the relationship are analyzed by using a quadratic polynomial regression model, and the coefficients in formula (a12) are obtained as follows: , and then determine the lateral contraction coefficient of the plane arc double-opening gate .

4. The method for calculating the flow rate of a planar arc double-opening gate according to claim 1 is characterized in that: In step (7), the formula (a7) is solved by an iterative method, and the right side of the formula (a7) is defined as Q=Q i 、Formula (a7) Left Q=Q i+1 , repeat the iterative calculation process several times, when the relative error When the flow rate of the plane arc double-open gate is taken Q =Q i+1 .

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