Flowmeter calibration method and device based on constant uniform flow

Abstract

The present invention relates to the field of flow velocity measurement technology, and in particular to a flow meter calibration method and device based on constant uniform flow, comprising an overflow water tank and a flow trough, wherein the water inlet end of the overflow water tank is connected to a water inlet pipe, and the water outlet end of the overflow water tank is connected to the water inlet end of the flow trough; utilizing the characteristics of the constant uniform flow in an open channel, the existing method of indirectly obtaining a constant flow velocity by driving a flow meter at a uniform speed in a static water flow by a calibration vehicle is abandoned, so that the water flow in the water inlet pipe enters the flow trough through the overflow water tank and the flow velocity in the flow trough is constant, thereby directly meeting the flow meter's measurement requirement for a constant flow velocity, saving calibration time, and improving the flow meter's calibration efficiency. The method has a simple structure and a small scale, and can greatly save space; at the same time, the constant uniform flow in the flow trough is more stable, thereby improving the stability of the flow meter calibration result, and also improving the flow meter's calibration accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of flow velocity measurement, and in particular to a flow meter calibration method based on constant uniform flow and a device thereof. Background Art

[0002] In liquid flow measurement, flow velocity is the most important parameter. Even slight changes in conditions can cause changes in the medium's flow pattern, and thus in flow rate. Thanks to the development of various liquid flow standard devices and the continuous application of new technologies by manufacturers, the technology for measuring liquid flow in closed pipes has matured, and the corresponding pipe flowmeters have high accuracy, reaching up to 0.1%. In open channels, rivers, and pipes, the primary instruments for measuring flow are various open channels, weirs, and flow troughs, while flow velocity is primarily measured using a velocimeter, an instrument for measuring the flow rate of water in rivers, lakes, and channels. Currently, the most commonly used instrument for flow velocity measurement in my country is the rotor velocimeter.

[0003] Currently, the calibration device for flowmeters mainly uses a linear open channel method. The principle is to use a calibration vehicle with adjustable speed to tow the flowmeter at a constant speed in the open channel to obtain the flowmeter flow calibration result. Currently, all flowmeter calibration devices have a linear open channel length of approximately 100m and a width of approximately 4m. In addition, the distance required for enclosed spaces results in a large footprint and extremely high site requirements for the testing agency. In addition, the calibration vehicle is expensive, difficult to repair and maintain, and the calibration cost is high. The flowmeter traceability in the flowmeter calibration device is completed through a universal counter and a secondary steel tape that have been calibrated and measured by the state. The flowmeter uses an indirect measurement calibration method to repeatedly measure the same data under the same measurement conditions and provide similar indications according to the measurement standard, resulting in low calibration efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a flow meter calibration method and device based on constant uniform flow, abandoning the existing method of tracing the flow meter through the length-time system, and adopting the flow system to trace the value of the flow meter, thereby improving work efficiency.

[0005] The technical problem solution of the present invention:

[0006] A flow meter calibration device based on constant uniform flow is characterized in that it includes an overflow water tank and a water flow trough, the water inlet end of the overflow water tank is connected to a water inlet pipe, and the water outlet end of the overflow water tank is connected to the water inlet end of the water flow trough.

[0007] It is further defined that the flow meter calibration device based on constant uniform flow also includes a lifting platform, which is located at the water outlet end of the water trough, and the water outlet end of the overflow water tank is movably connected to the water inlet end of the water trough through a connecting piece, and the lifting platform is used to adjust the angle of the water trough and the horizontal direction.

[0008] It is further defined that the connecting member is a compensator or an expansion joint.

[0009] It is further defined that the water inlet end of the overflow water tank is located below the water outlet end of the overflow water tank, and an overflow port is provided on the side wall of the overflow water tank. The overflow port is located above the water inlet end of the overflow water tank, and the water depth of the water flow trough is adjusted according to the size of the overflow port opening.

[0010] It is further defined that the flow meter calibration device based on constant uniform flow also includes an overflow valve, which is arranged at the overflow port to adjust the size of the water flow through the overflow port.

[0011] It is further defined that the flow meter calibration device based on constant uniform flow also includes a liquid level meter, which is arranged on the water flow trough and connected to the water flow trough.

[0012] It is further defined that the flow meter calibration device based on constant uniform flow also includes a total water inlet flowmeter and an overflow water flowmeter, the total water inlet flowmeter is arranged on the water inlet pipe, the overflow port is connected to an overflow pipe, and the overflow water flowmeter is arranged on the overflow pipe.

[0013] It is further defined that the flow meter calibration device based on constant uniform flow also includes a return water trough, the overflow water tank is arranged in the return water trough, the water inlet pipe passes through the return water trough and is connected to the overflow water tank, the water outlet end of the overflow pipe and the water outlet end of the flow trough are both located directly above the return water trough, and the lifting platform is located outside the return water trough.

[0014] A method for calibrating a flowmeter based on a constant uniform flow is characterized in that, based on the above-mentioned flowmeter calibration device based on a constant uniform flow, the method comprises the following steps:

[0015] S1. Install the flow meter to be tested on the water trough and fill the overflow tank with water at a uniform speed through the water inlet pipe;

[0016] S2, adjust the water depth of the water tank through the overflow valve;

[0017] S3. Setting the water flow velocity in the water trough, and adjusting the horizontal angle of the water trough by the lifting platform according to the set water flow velocity in the water trough;

[0018] S4. Determine the flow rate of the water trough according to the difference between the flow rate of the water inlet pipe and the flow rate of the overflow pipe, and determine the real-time flow rate of the water trough according to the flow rate of the water trough;

[0019] S5. The flow meter to be tested is calibrated by comparing the real-time flow rate of the water flow trough with the measured flow rate of the flow meter to be tested.

[0020] Further defined, the step S3 is specifically as follows:

[0021] S31. Calculate the flow cross-sectional area and the wetted perimeter of the water trough according to the width and water depth of the water trough;

[0022] S32. Calculate the hydraulic radius of the water trough based on the flow cross-sectional area and the wetted perimeter of the water trough;

[0023] S33, calculating the relative roughness of the water trough according to the hydraulic radius of the water trough;

[0024] S34, calculating the resistance coefficient of the water trough according to the relative roughness of the water trough;

[0025] S35, setting the water flow velocity of the water trough, and calculating the hydraulic loss in the water trough according to the resistance coefficient of the water trough, the length of the water trough, and the set water flow velocity of the water trough;

[0026] S36, calculating the angle between the water channel and the horizontal direction according to the hydraulic loss of the set water channel and the length of the water channel;

[0027] S37. Determine the lifting height of the lifting platform according to the length of the water trough and adjust the deflection angle of the water trough.

[0028] The beneficial effects of the present invention are:

[0029] 1. The present invention utilizes the characteristics of constant uniform flow in open channels, and abandons the existing method of indirectly obtaining a constant flow rate by driving a flow meter with a calibration vehicle at a uniform speed in a static water flow. After the water flow in the water inlet pipe passes through the overflow water tank and enters the flow trough, the flow rate in the flow trough is constant, thereby directly realizing the flow meter's measurement requirement for a constant flow rate. The overflow water at another place is then measured using a standard flow meter, and the difference is obtained by comparing it with the total water inlet flow meter to obtain the instantaneous flow in the flow trough, and then the flow rate value is obtained, which saves time and improves the calibration efficiency of the flow meter. It has a simple structure and a small scale, which can greatly save space; at the same time, the constant uniform flow in the flow trough is more stable, which improves the stability of the calibration results of the flow meter, and also improves the calibration accuracy of the flow meter.

[0030] 2. The present invention can adjust the inclination angle of the water flow trough through the lifting platform, thereby controlling the water flow velocity in the water flow trough and realizing the calibration of the flow meter under different water flow conditions. It has a simple structure and is easy to operate. It also reduces the overall volume and the occupied area, making the cost low. It has complete detection functions and is suitable for popularization and use.

[0031] 3. By setting the overflow valve, the height of the water level in the water trough can be determined by adjusting the height of the overflow valve, so that the flow meter can be calibrated under different water level conditions. The operation is simple and the adjustment is convenient. At the same time, the water overflowing from the overflow tank flows out through the overflow pipe. The overflow flow collected by the overflow water flowmeter and the inlet flow collected by the total water inlet flowmeter can accurately obtain the flow in the water trough, making the flow calculation of the water trough more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the main structure of the current meter calibration device based on constant uniform flow of the present invention;

[0033] Figure 2 Schematic diagram of the top view of the flow meter calibration device based on constant uniform flow of the present invention;

[0034] Figure 3 Schematic diagram of the overall structure of the current meter calibration device based on constant uniform flow of the present invention;

[0035] Figure 4 This is a schematic diagram of the cross-sectional structure of the connecting groove and the water flow groove of the present invention;

[0036] 1-Overflow water tank; 2-Water flow trough; 3-Lifting platform; 4-Water inlet pipe; 5-Overflow pipe; 6-Overflow valve; 7-Liquid level meter; 8-Total water inlet flow meter; 9-Overflow water flow meter; 10-Return water trough; 11-Connecting trough. DETAILED DESCRIPTION

[0037] Example 1

[0038] The characteristics of constant uniform flow in open channel are that the flow velocity is constant along the flow, the streamlines are a series of parallel straight lines, the water depth of the open channel and the velocity distribution of the cross section are constant along the flow. Also remains unchanged along the flow.

[0039] refer to Figures 1 to 3The present invention provides a flowmeter calibration device based on constant uniform flow, comprising an overflow tank 1, a water trough 2 and a lifting platform 3; in the initial state, the water trough 2 is arranged horizontally, the head end of the water trough 2 is movably connected to the water outlet of the overflow tank 1 through a connecting piece, the end of the water trough 2 is connected to the lifting platform 3, and the lifting platform 3 is installed at the bottom of the water trough 2. The lifting platform 3 can be selectively connected to the bottom of the water trough 2. At this time, baffles are set on the opposite sides of the water trough 2, and the lifting platform 3 is set between the two baffles to prevent the water trough 2 from shaking on the lifting platform 3; preferably, the top of the lifting platform 3 is hinged to the bottom of the water trough 2, and the raising and lowering of the lifting platform 3 directly drives the end of the water trough 2 to rotate up and down in the vertical plane with the center of the connecting piece as the center of the circle; it should be noted that when the lifting platform 3 is hinged to the bottom of the water trough 2, due to the flow The end of the water trough 2 moves up and down along the axis of the lifting platform 3 when it rotates up and down, causing the head end of the water trough 2 to approach or move away from the overflow water tank 1 when the water trough 2 rotates. At this time, the connecting piece uses a component that can provide rotation and movement. At this time, the connecting piece can be selected as a compensator or an expansion joint. While the end of the water trough 2 rotates, the head end of the water trough 2 can also rotate and move relative to the overflow water tank 1 through the connecting piece, so that the lifting platform 3 drives the water trough 2 to deflect up and down, thereby adjusting the deflection angle of the water trough 2 and the horizontal direction through the lifting platform 3, and then adjusting the angle between the water trough 2 and the horizontal direction. At the same time, the water trough 2 can maintain the connection with the overflow water tank 1 when it rotates up and down through the lifting platform 3, ensuring that the water in the overflow water tank 1 can still flow into the water trough 2 after the height of the end of the water trough is adjusted, thereby avoiding water seepage.

[0040] Further explanation, the connecting part can also be selected as a rubber tube. At this time, in order to prevent the water trough 2 from tilting downward at its head end due to its own weight, thereby causing the angle between the water trough 2 and the horizontal direction to deviate from the adjustment height of the lifting platform 3, it is necessary to set a lifting support rod at the head end of the water trough 2. The lifting support rod is set at the bottom of the water trough 2, and the top of the lifting support rod is in contact with the bottom surface of the water trough 2. The top of the lifting support rod can be selected as a spherical structure or a cylindrical structure to ensure the stable rotation of the water trough 2. The angle adjustment of the water trough 2 and the horizontal direction can be achieved by adjusting the height of the head end and / or tail end of the water trough 2.

[0041] Usually, the end of the water trough 2 is adjusted downward, and the speed of the water flow in the water trough 2 is adjusted by controlling the deflection angle of the water trough 2, so as to realize the measurement and calibration of the flow meter to be tested under different water flow speed conditions; in order to facilitate the subsequent calibration calculation, it is preferred that the interior of the water trough 2 has a rectangular structure.

[0042] In order to realize calibration of the flowmeter to be tested under different liquid level height conditions, it is preferred to open an overflow port on the overflow water tank 1. The overflow port is opened on the peripheral side of the overflow water tank 1, and the upper edge of the overflow port is flush with the upper edge of the overflow water tank 1. The water outlet of the overflow water tank 1 is located on the opposite side of the overflow port. The water inlet flow of the overflow water tank 1 is fixed. The liquid level height of the overflow water tank 1 is adjusted by adjusting the height of the bottom of the overflow port, thereby adjusting the liquid level height entering the flow trough 2 from the overflow water tank 1. Since the water inlet flow rate entering the overflow water tank 1 is the same and the pipe diameter is the same, that is, the water inlet flow rate is the same, the flow rate in the flow trough 2 can be obtained by obtaining the overflow flow rate of the overflow port, and the water flow rate in the flow trough 2 can be calculated when the width and liquid level height of the flow trough 2 are known. In order to achieve the measurement of different flow rates and avoid opening overflow ports of different heights on each overflow water tank 1, it is further preferred that the flow meter calibration device based on constant uniform flow also includes an overflow valve 6, and an overflow valve 6 is arranged on the overflow port. The overflow valve 6 is movably connected to the overflow port. When the upper end of the overflow valve 6 is flush with the upper edge of the overflow water tank 1, the highest water level of the overflow water tank 1 is flush with the upper end of the overflow valve 6. When the overflow valve 6 slides downward, the water level in the overflow water tank 1 is also flush with the upper end of the overflow valve 6, so that the liquid level height in the overflow water tank 1 is controlled by the lifting and lowering of the overflow valve 6, and then the liquid level height of the water flow entering the water trough 2 from the water outlet is controlled. Preferably, an overflow pipe 5 is connected to the overflow port to facilitate the collection of overflow water and unified discharge.

[0043] For further reference, Figure 4 In order to facilitate the acquisition of the height of the liquid level in the water trough 2, the flow meter calibration device based on constant uniform flow preferably also includes a liquid level meter 7. The liquid level meter 7 is set on the water trough 2 to obtain the real-time liquid level in the water trough 2. In order to avoid the liquid level meter 7 being set in the water trough 2 and interfering with the constant uniform flow in the water trough 2, a connecting groove 11 is preferably set on the side wall of the water trough 2, so that the connecting groove 11 is connected to the bottom of the water trough 2, and the connecting vessel principle is used to ensure that the liquid level in the circulation groove is the same as the liquid level height in the water trough 2. At this time, the liquid level meter 7 is set in the connecting groove 11 to determine the real-time liquid level height in the water trough 2, thereby ensuring the stability and reliability of the constant uniform flow in the water trough 2 and realizing high-precision calibration of the flow meter.

[0044] Furthermore, in order to calculate the water flow rate in the water trough 2, the difference obtained by subtracting the overflow flow rate from the inlet flow rate is selected as the water flow rate in the water trough 2. The flowmeter calibration device based on constant uniform flow preferably also includes a total inlet flowmeter 8 and an overflow water flowmeter 9. The total inlet flowmeter 8 is set on the water inlet pipe 4, and the overflow water flowmeter 9 is set on the overflow pipe 5, so as to obtain the corresponding flow rate. The data collection and calculation are convenient, and the data can also be recorded for easy backtracking. It is also possible to choose to set a ratio tube sensor in the water trough 2 to realize real-time monitoring of the flow velocity of the water flow in the water trough 2, thereby further improving the calibration accuracy.

[0045] The water in the overflow tank 1 is pumped into the overflow tank 1 by the water pump, and the water outlet end of the overflow pipe 5 is connected to the main water tank, thereby avoiding water waste, realizing water recycling, saving resources and saving costs.

[0046] During use, the flow in the water trough 2 is calculated and adjusted as needed, and then the angle between the water trough 2 and the horizontal direction is adjusted, so that a constant uniform flow can be obtained in the water trough 2. The flow meter to be tested can be installed in the water trough 2 to realize the calibration of the flow meter to be tested. It can be used immediately after installation, with high calibration efficiency, more stable calibration results, and improved calibration accuracy. Compared with the existing method of static water trough measurement, the method does not require the use of the existing distance-length system to use the calibration vehicle to move the flow meter to obtain the measurement result of the flow meter to be tested, and then the value close to the uniform speed time period is selected for calculation. As a result, in order to ensure the accuracy of the result, the flow meter to be tested needs to be moved for a long time, which greatly reduces the calibration efficiency of the flow meter to be tested. At the same time, the calibration vehicle is used to drive the flow meter to be tested to move so that a relative flow velocity is formed between the flow meter to be tested and the water flow. At this time, the calibration vehicle needs to maintain a uniform speed, which is difficult, and the stability of the uniform speed is low, so that the accuracy of the calibration result obtained by the existing distance-time system is low.

[0047] Example 2

[0048] Based on Example 1, this embodiment provides a method for using a flow meter calibration device based on a constant uniform flow, comprising the following steps:

[0049] S1, fill the overflow tank 1 with water at a constant speed through the water inlet pipe 4, and install the flow meter to be tested on the water flow tank 2;

[0050] In step S1, the water in the main water tank is passed into the overflow water tank 1 through a water pump, and the water trough 2 is placed horizontally. By observing the changes in the value of the total water inlet flowmeter 8 and the changes in the value of the overflow water flowmeter 9, it is determined that the flow in the overflow pipe 5 and the flow in the water inlet pipe 4 are stable. At this time, the flow in the water trough 2 is stable, and then the flow meter to be tested is connected to the water trough 2 according to the detection requirements and prepared for detection.

[0051] S2, adjust the water depth in the water trough 2 by adjusting the height of the overflow valve 6;

[0052] In step S2, first determine the water depth that the flowmeter to be tested needs to be tested, and then gradually adjust the height of the overflow valve 6, that is, adjust the position of the bottom end of the overflow port on the overflow water tank 1, thereby realizing the adjustment of the liquid level height of the overflow water tank 1 and controlling the liquid level in the water flow trough 2. At the same time, with the help of the liquid level meter 7, it is usually chosen to connect the flowmeter to be tested to the opposite side of the liquid level meter 7 to ensure that the liquid level value of the liquid level meter 7 is the liquid level of the flowmeter to be tested, and install the liquid level meter 7 in the connecting groove 11 on the side wall of the water flow trough 2, so as to accurately obtain the liquid level height of the corresponding position, that is, the water depth in the water flow trough 2.

[0053] S3, setting the water flow speed of the water trough 2, and adjusting the inclination angle of the water trough 2 according to the water flow speed of the water trough 2;

[0054] When the lifting platform 3 is lowered, the water tank 2 is lifted up and the flow rate is increased, and the flow rate of the water tank 2 is increased. When the lifting platform 3 is lowered, the water tank 2 is lifted up and the flow rate is increased. When the lifting platform 3 is lowered, the water tank 2 is lifted up and the flow rate is increased. When the lifting platform 3 is lowered, the flow rate is increased, and the flow rate is increased. When the lifting platform 3 is lowered, the flow rate is increased, and the flow rate is increased. When the lifting platform 3 is lowered, the flow rate is increased, and the flow rate is increased.

[0055] S4, determining the flow rate of the water trough 2 according to the difference between the flow rate of the water inlet pipe and the flow rate of the overflow pipe, and determining the real-time flow rate of the water trough 2 according to the determined flow rate of the water trough 2;

[0056] In step S4, the flow rate in the water trough 2 is obtained by subtracting the display result of the total water inlet flow meter 8 from the display result of the overflow water flow meter 9, and then the real-time flow rate of the water trough 2 can be calculated by combining the length and width dimensions and water level depth of the water trough 2.

[0057] S5. Compare the real-time flow rate with the measured flow rate of the flow meter to be tested, and complete the calibration of the flow meter to be tested.

[0058] Finally, in step S5, the calculated real-time flow velocity is compared with the flow velocity measured by the flow meter to complete the calibration of the flow meter.

[0059] Specifically, step S3 includes the following steps:

[0060] S31, calculating the flow cross-sectional area A of the water trough 2 and the wetted perimeter χ of the water trough 2 according to the width of the water trough 2 and the water depth in the water trough 2;

[0061] A=x*h

[0062] χ=x*h*2

[0063] Wherein, x is the width of the water trough 2, h is the water depth in the water trough 2, and the water depth in the water trough 2 is measured by the liquid level meter 7.

[0064] S32, calculating the hydraulic radius R of the water trough 2 according to the flow cross-sectional area and the wetted perimeter of the water trough 2;

[0065]

[0066] S33, calculate the relative roughness K of the water channel 2 according to the hydraulic radius of the water channel 2 and the roughness of the inner wall of the water channel 2 s ;

[0067]

[0068] Wherein, g is the acceleration due to gravity, and n is the roughness of the inner wall of the water trough 2 . The inner wall roughness can be obtained according to the material of the water trough 2 .

[0069] S34, calculating the resistance coefficient λ of the water trough 2 according to the relative roughness of the water trough 2;

[0070] λ=0.185(K s / d) 1 / 3

[0071] Wherein, d=4R.

[0072] S35, setting the water velocity in the water trough 2, and calculating the hydraulic loss h in the water trough 2 according to the resistance coefficient of the water trough 2, the length of the water trough 2 and the set water velocity of the water trough f ;

[0073]

[0074] Wherein, L is the length of the water channel 2, and V is the set water flow velocity of the water channel.

[0075] S36, calculating the angle θ between the water channel 2 and the horizontal direction according to the hydraulic loss of the water channel 2 and the length of the water channel 2;

[0076]

[0077]

[0078] S37 , determining the lifting height of the lifting platform 3 according to the length of the water trough 2 , and adjusting the deflection angle of the water trough 2 to rotate the water trough 2 to a corresponding tilt angle.

[0079] To further explain, let's take a specific experiment as an example:

[0080] The length L of the water trough 2 is selected to be 10m, and the width x of the water trough 2 is selected to be 0.5m, that is, the width between the inner walls of the water trough 2 is 0.5m. By adjusting the overflow valve 6, the water depth h in the water trough 2 measured by the liquid level meter 7 is 0.25m. The water trough 2 uses stainless steel as the inner wall, and its inner wall roughness n = 0.012.

[0081] At this time, the calculation is:

[0082] The cross-sectional area of ​​the water channel 2 is A = x*h = 0.5 × 0.25 = 0.125 m 2 ;

[0083] The wetted perimeter of the water channel 2 is x = x*h*2 = 0.5 + 0.25×2 = 1 m;

[0084] Hydraulic radius of flow channel 2

[0085] Relative roughness of water channel 2

[0086] Where g is 9.8m / s 2 According to the Moody diagram of the pipeline experiment, when λ=0.185(K s / d) 1 / 3 When K s / d≈0.001~0.05, so calculate K s / d, where d = 4R = 0.5m, that is The above requirements are met, so the resistance coefficient of the water channel 2 is calculated to be λ = 0.185 (K s / d) 1 / 3 =0.185×0.0015 1 / 3 =0.021.

[0087] When the water flow velocity in the water channel 2 is set to V = 1m / s, the hydraulic loss in the water channel 2 is obtained

[0088] Inclination angle of water channel 2

[0089] The total flow rate q is measured by the total water flow meter 8 on the water inlet pipe 4总 Equal to the overflow flow rate q measured by the overflow water flow meter 9 on the overflow pipe 5 溢 and the flow rate q in flow channel 2 槽 The sum can be calculated to get q 槽 =q 总 -q 分 , and then according to q 槽 =A×V 实 ×3600s can be calculated

[0090] According to the V measured by the flow meter to be tested 测 With V 实 Calculate and complete the flowmeter to be tested at 0.25m water level and V 实 Calibration under flow rate conditions: in this way, by changing the position of the overflow valve 6 and changing the angle of the water flow channel 2, the measurement of the flow meter to be tested under different water levels and different flow rate conditions is achieved, and finally the calibration of the flow meter to be tested is completed.

Claims

1. A method for calibrating a flowmeter based on a constant uniform flow, characterized in that: The following steps are involved: S1. Install the flow meter to be tested on the water trough (2), and fill the overflow water tank (1) with water at a uniform speed through the water inlet pipe (4); S2, adjusting the water depth of the water trough (2) through the overflow valve (6); S3, setting the water flow velocity in the water trough (2), and adjusting the angle between the water trough (2) and the horizontal direction through the lifting platform (3) according to the set water flow velocity in the water trough (2); S4, determining the flow rate of the water trough (2) according to the difference between the flow rate of the water inlet pipe and the flow rate of the overflow pipe, and determining the real-time flow velocity of the water trough (2) according to the flow rate of the water trough (2); S5, completing the calibration of the flow meter to be tested by comparing the real-time flow rate of the water flow trough (2) with the measured flow rate of the flow meter to be tested; A flowmeter calibration device based on a constant uniform flow flow flowmeter calibration method comprises an overflow water tank (1) and a flow trough (2), wherein the water inlet end of the overflow water tank (1) is connected to a water inlet pipe (4), and the water outlet end of the overflow water tank (1) is connected to the water inlet end of the flow trough (2); an overflow port is provided on a side wall of the overflow water tank (1); The current meter calibration device based on constant uniform flow further comprises a lifting platform (3), wherein the lifting platform (3) is located at the water outlet of the water trough (2), the water outlet of the overflow water tank (1) is movably connected to the water inlet of the water trough (2) via a connecting piece, and the lifting platform (3) is used to adjust the angle of the water trough (2) with the horizontal direction; The constant uniform flow-based flow meter calibration device further comprises an overflow valve (6), which is arranged at the overflow port and is used to adjust the size of the water flow passing through the overflow port.

2. The method for calibrating a flowmeter based on a constant uniform flow according to claim 1, characterized in that: The connecting piece is a compensator or an expansion joint.

3. The method for calibrating a flowmeter based on a constant uniform flow according to claim 1, characterized in that: The water inlet end of the overflow water tank (1) is located below the water outlet end of the overflow water tank (1), and the overflow port is located above the water inlet end of the overflow water tank (1). The water depth of the water flow channel (2) is adjusted according to the size of the overflow port opening.

4. The method for calibrating a flowmeter based on a constant uniform flow according to claim 3, characterized in that: The constant uniform flow-based flow meter calibration device further comprises a liquid level meter (7), wherein the liquid level meter (7) is arranged on the water flow trough (2) and is in communication with the water flow trough (2).

5. The method for calibrating a flowmeter based on a constant uniform flow according to claim 4, characterized in that: The constant uniform flow-based flowmeter calibration device further comprises a total water inlet flowmeter (8) and an overflow water flowmeter (9); the total water inlet flowmeter (8) is arranged on the water inlet pipe (4); the overflow port is connected to an overflow pipe (5); and the overflow water flowmeter (9) is arranged on the overflow pipe (5).

6. The method for calibrating a flowmeter based on a constant uniform flow according to claim 5, characterized in that: The current meter calibration device based on constant uniform flow also includes a return water trough (10), the overflow water tank (1) is arranged in the return water trough (10), the water inlet pipe (4) passes through the return water trough (10) and is connected to the overflow water tank (1), the water outlet end of the overflow pipe (5) and the water outlet end of the flow trough (2) are both located directly above the return water trough (10), and the lifting platform (3) is located outside the return water trough (10).

7. The method for calibrating a flowmeter based on a constant uniform flow according to claim 1, characterized in that: The step S3 is specifically as follows: S31, calculating the flow cross-sectional area of ​​the water trough (2) and the wetted perimeter of the water trough (2) according to the width of the water trough (2) and the water depth of the water trough (2); S32, calculating the hydraulic radius of the water trough (2) based on the flow cross-sectional area of ​​the water trough (2) and the wetted perimeter of the water trough (2); S33, calculating the relative roughness of the water trough (2) according to the hydraulic radius of the water trough (2); S34, calculating the resistance coefficient of the water trough (2) according to the relative roughness of the water trough (2); S35, setting the water flow velocity of the water trough (2), and calculating the hydraulic loss in the water trough (2) according to the resistance coefficient of the water trough (2), the length of the water trough (2) and the set water flow velocity of the water trough; S36, calculating the angle between the water channel (2) and the horizontal direction according to the hydraulic loss of the water channel (2) and the length of the water channel (2); S37, determining the lifting height of the lifting platform (3) according to the length of the water trough (2) and adjusting the deflection angle of the water trough (2).

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