A bidirectional spiral water turbine hydraulic test device and control method

Abstract

The application discloses a kind of bidirectional operation spiral water turbine hydraulic test device and control method, including structural steel frame, upstream water tank, downstream water tank, circulating pipeline, water turbine bidirectional test section and regulation component;Structural steel frame is used to install and firm upstream water tank, downstream water tank, water turbine test section and regulation component device;Upstream water tank includes water storage tank, overflow plate and reflux tank;Downstream water tank includes water storage tank, water supply pump, cofferdam baffle, water passage grille;Water turbine test section includes spiral water turbine runner, guide vane, built-in motor, peripheral pipeline;Regulation part includes the water level overflow plate adjustment of upper water tank, the flow valve adjustment of test section inlet pipeline, spiral water turbine speed regulation, cofferdam flow monitoring of downstream water tank.Spiral water turbine hydraulic test device is realized under the condition of water turbine in positive and negative direction operation Multiple operating conditions of hydraulic performance research, for spiral water turbine hydraulic design development, hydraulic performance research supplementary test data support.

Description

Technical Field

[0001] This invention belongs to the field of hydropower technology, specifically relating to a hydraulic test device and control method for a bidirectional spiral turbine. Background Technology

[0002] Currently, research on hydropower technology mainly focuses on the performance optimization of traditional hydropower equipment and the design and development of new hydropower equipment. Unlike traditional hydropower, new hydropower equipment often operates in remote areas with low head and low flow velocity. Therefore, its design requirements often necessitate features such as environmental friendliness, simple structure, easy installation, and stable operation.

[0003] As a typical environmentally friendly type of water turbine, the screw turbine has diverse structural forms, but it generally features a blade shape based on the Archimedean spiral. This effectively handles changes in internal pressure and velocity gradients while also reducing the probability of injury from fish collisions. Compared to conventional constant-diameter screw turbines, variable-diameter screw turbines operate under more diverse conditions and exhibit more complex internal and external characteristics.

[0004] In existing technologies, numerical simulation is usually used to calculate and analyze the operating conditions of various types of screw turbines in order to improve the working performance of screw turbines at low cost and in a short period of time. However, numerical simulation results for some operating conditions have large errors and lack experimental verification. Therefore, it is necessary to establish an effective hydraulic test device for screw turbines to analyze and evaluate their performance. Summary of the Invention

[0005] In order to solve the technical problems of lack of relevant experimental data and insufficient accuracy of hydraulic performance analysis in the design and optimization of variable diameter spiral turbines in the background art, the present invention aims to provide a hydraulic test device and control method for a spiral turbine that can operate in both directions, and to analyze and study the hydraulic performance of the spiral turbine by building a model test bench.

[0006] To solve the technical problem, the technical solution of the present invention is as follows:

[0007] A bidirectional spiral turbine hydraulic testing device is disclosed. The device includes a downstream water tank, a circulation pipeline, a bidirectional turbine testing section, and a control component. An upstream water tank is located at the top of the downstream water tank, and the upstream and downstream water tanks are connected by the circulation pipeline. The circulation pipeline contains the bidirectional turbine testing section, within which a spiral turbine runner is installed. When the hydraulic testing device is in operation, the control component controls the head, flow rate, and spiral turbine runner speed entering the bidirectional turbine testing section, thereby changing the operating conditions of the testing device.

[0008] Furthermore, it also includes: a structural steel frame, which is used to support and fix the upstream water tank, downstream water tank, circulation pipeline, bidirectional test section of turbine, and control components.

[0009] Furthermore, the control components include: a water level overflow plate installed in the upstream water tank, a flow valve installed in the circulation pipeline, a motor controller installed in the bidirectional test section of the turbine, and a water supply pump installed in the downstream water tank.

[0010] Furthermore, the bidirectional test section of the water turbine includes: a spiral water turbine runner, peripheral pipelines, guide vanes, and an internal motor. The peripheral pipelines are connected through an outer support plate of the internal motor. The two sides of the test section are connected to the circulation pipelines through flanges. The axis of the water turbine coincides with the horizontal center line of the upstream and downstream circulation pipelines.

[0011] The spiral turbine runner includes a hub and blades. The hub is conical and horizontally positioned, with a diffusion angle of [missing information]. The blade profile is an Archimedean spiral, with the following specific parameters: small end diameter D1, large end diameter D2, number of blades N, pitch P, and axial length of the runner L.

[0012] The spiral turbine runner is connected to the built-in motor via a shaft, and its radial and axial displacement is constrained by bearings.

[0013] Furthermore, the upstream end of the circulation pipeline is connected to the upstream water tank, and the pipeline diameter is [missing information]. The downstream end is connected to the downstream water tank, and the pipe diameter is [missing information]. The upstream pipe diameter With downstream pipe diameter The transition point is located on the upstream side of the bidirectional test section of the turbine.

[0014] Furthermore, the upstream water tank includes: a water storage chamber, a return flow chamber, and a water level overflow plate;

[0015] The water level overflow plate includes two stationary plates and one movable plate, which are used to separate the water storage chamber and the return chamber; the water level in the water storage chamber can be adjusted by moving the movable plate up and down.

[0016] The diameter of the side of the water storage cavity and the upstream of the circulation pipe is [missing information]. The pipeline is connected, and the pipeline at the bottom of the water storage cavity is connected to the water supply pump in the downstream water tank; the water supply pump realizes the water circulation of the test device by drawing water from the downstream water tank and pumping it into the water storage cavity.

[0017] The bottom of the return cavity is connected to the downstream water tank through a pipe. The water overflowing from the water storage cavity is collected in the return cavity and flows back to the downstream water tank through the bottom pipe to stabilize the water level in the water storage cavity.

[0018] Furthermore, a flow valve is connected to the circulation pipeline between the upstream water tank and the bidirectional test section of the turbine; the flow valve can control the flow rate entering the bidirectional test section of the turbine by adjusting its opening.

[0019] Furthermore, the downstream water tank includes a water storage tank, a dike partition, a water flow grid, and a water supply pump;

[0020] The water storage tank is fixed to the lower part of the structural steel frame. The volume of the water storage tank is not less than twice the volume of the upstream water storage tank. It is used to store the circulating water during normal operation of the test device. The cofferdam partition and the water-passing grid are both arranged in the water storage tank. The water-passing grid is distributed between the outlet of the downstream circulation pipeline and the cofferdam partition to stabilize the water flow through the cofferdam partition.

[0021] The cofferdam partition has a rectangular cross-section and a water passage width of B. After the water flows through the cofferdam partition to form a stable flow, the flow rate can be calculated according to the following formula. Measurement:

[0022]

[0023]

[0024] In the formula: m is the flow coefficient of the cofferdam diaphragm, which can be determined experimentally; k is the contraction coefficient of the water tongue at the top of the weir. The velocity coefficient of the weir; is the ratio of the average pressure head to the total head at the weir crest cross section; g is the local gravitational acceleration; H0 is the dynamic pressure head upstream of the cofferdam diaphragm.

[0025] The water supply pump is a submersible pump, with its inlet end submerged below the water surface of the storage tank and its outlet end connected to the bottom pipe of the storage tank, pumping water from the downstream tank to the upstream tank.

[0026] Furthermore, when the hydraulic test device for the spiral turbine is running in the forward direction, the small end of the spiral turbine runner faces the upstream flow; when the hydraulic test device for the spiral turbine is running in the reverse direction, the large end of the spiral turbine runner faces the upstream flow.

[0027] When switching between forward and reverse operation of the spiral turbine hydraulic test device, the test device is in a stopped state. Loosen the connecting bolts of the connecting flanges at both ends of the bidirectional test section of the turbine, rotate the bidirectional test section of the turbine 180°, and then tighten the installation to realize the bidirectional switching of the hydraulic test device.

[0028] A method for controlling a bidirectional spiral turbine hydraulic test, the method being applied to any of the bidirectional spiral turbine hydraulic test devices described above, the method comprising:

[0029] Step 1: The water supply pump starts running, sending water from the downstream water tank to the upstream water tank;

[0030] Step two, the water level overflow plate is adjusted to the specified height H, and the flow valve is opened to the specified degree. The flow rate can be measured once based on the relationship curve between the valve flow coefficient and the valve opening. Part of the water flow in the upstream tank enters the bidirectional test section of the turbine through the circulation pipeline, while another part flows out through the overflow plate and then enters the downstream tank through the return cavity. The formula for calculating the flow rate in one measurement is as follows:

[0031]

[0032] In the formula: C v Where is the valve's flow coefficient; N1 is a constant, taken as 0.0865; F p This is the pipeline geometry coefficient, which is set to 1 when the control valve diameter matches the pipeline diameter. P v The static pressure difference of the valve; This represents the density of the fluid under the current pressure and temperature conditions. The density of water at 15℃;

[0033] Step 3: The bidirectional test section of the water turbine is submerged in the water flow. The built-in motor controller controls the motor to drive the spiral water turbine runner to run at a specified speed, and monitors the shaft torque T and speed n signal parameters.

[0034] Step four: After passing through the bidirectional test section of the turbine, the water flows into the downstream water tank via the downstream circulation pipeline. After being stabilized by the water grid, it further flows through the cofferdam baffle. After reading the water level height upstream of the cofferdam baffle, the flow rate is measured a second time using the following formula:

[0035]

[0036]

[0037] In the formula, m is the flow coefficient of the cofferdam diaphragm, which can be determined experimentally; k is the contraction coefficient of the water tongue at the top of the weir. The velocity coefficient of the weir; is the ratio of the average pressure head to the total head at the weir crest cross section; g is the local gravitational acceleration; H0 is the dynamic pressure head upstream of the cofferdam diaphragm.

[0038] Step 5: The control component compares the results of the first and second flow measurements. If the relative error of the flow is within 5%, the average of the first and second flow measurements is taken as the flow rate Q. Otherwise, the test condition should be repeated.

[0039] Step six: After obtaining parameters such as head H, flow rate Q, torque T, and rotational speed n under the test conditions, determine the efficiency of the screw turbine under the current operating conditions. The calculation is performed using the following formula:

[0040] .

[0041] Compared with the prior art, the advantages of the present invention are as follows:

[0042] 1. The water flow in the test device can be circulated through the upstream water tank, circulation pipeline and downstream water tank. The external conditions of the spiral turbine can be changed according to the control components such as the overflow plate of the upstream water tank and the flow valve, so that the model spiral turbine can be tested under different working conditions such as head and flow rate.

[0043] 2. Considering the bidirectional flow of the spiral turbine, the turbine is connected to the upstream and downstream circulation pipelines via connecting flanges on both sides of the bidirectional test section. By changing the connection direction between the turbine test section and the circulation pipeline, forward and reverse hydraulic tests of the spiral turbine can be achieved, thus expanding the operating condition range of the spiral turbine model test.

[0044] 3. By using the flow coefficient characteristics of the flow valve and the flow measurement of the rectangular cofferdam in the downstream water tank, secondary measurement and calibration of the flow can be achieved during the test, ensuring the accuracy of the flow data obtained through the bidirectional test section of the turbine in the test device.

[0045] 4. By collecting data from various parts of the control components, the operating parameters of the spiral turbine under various test conditions, such as the operating head, flow rate, torque, and speed, can be obtained. This allows for the evaluation and analysis of the external characteristics of the spiral turbine. Furthermore, by observing the bidirectional test section of the turbine using colorants or laser particle methods, a qualitative study of the hydraulic characteristics during the operation of the spiral turbine can be conducted. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of the bidirectional spiral turbine hydraulic test device described in this invention;

[0047] Figure 2 This is a schematic diagram of the upstream water tank described in this invention;

[0048] Figure 3 This is a schematic diagram of the operation of the water level overflow plate in the upstream water tank according to the present invention;

[0049] Figure 4 This is a schematic diagram of the circulation pipeline between the upstream water tank and the downstream water tank described in this invention;

[0050] Figure 5 This is a schematic diagram of the structure of the spiral turbine described in this invention;

[0051] Figure 6 This is a schematic diagram of the bidirectional test section of the water turbine described in this invention;

[0052] Figure 7 This is a schematic diagram of the downstream water tank described in this invention;

[0053] Figure 8 This is a schematic diagram of the working process of the bidirectional spiral turbine hydraulic test device described in this invention. Detailed Implementation

[0054] The specific implementation of the present invention is described below with reference to embodiments:

[0055] It should be noted that the structures, proportions, sizes, etc. shown in this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0056] Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity of description and are not intended to limit the scope of the invention. Any changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0057] Example 1:

[0058] like Figure 1-7 As shown, a hydraulic test device for a bidirectional spiral turbine includes a structural steel frame, an upstream water tank, a downstream water tank, a circulation pipeline, a bidirectional test section for the turbine, and control components.

[0059] The bidirectional test section of the turbine is connected to the upstream and downstream water tanks through a circulation pipeline; the structural steel frame is used to support and fix the upstream and downstream water tanks, the circulation pipeline, the bidirectional test section of the turbine, and the control components.

[0060] When the hydraulic turbine test device is running, the control components control the head, flow rate and the speed of the spiral turbine runner entering the bidirectional test section of the turbine, thereby changing the working conditions of the test device.

[0061] In this embodiment, the control components include a water level overflow plate installed in the upstream water tank, a flow valve in the circulation pipeline, a motor controller in the bidirectional test section of the turbine, and a water supply pump in the downstream water tank.

[0062] In this embodiment, the bidirectional test section of the turbine includes peripheral pipelines, a turbine runner, guide vanes, and an internal motor. The peripheral pipelines are connected through an outer support plate of the internal motor, and the two sides of the test section are connected to the circulation pipelines through connecting flanges. The turbine axis coincides with the horizontal centerline of the upstream and downstream circulation pipelines.

[0063] The spiral turbine runner includes a hub and blades. The hub is conical and horizontally positioned, with a diffusion angle of [missing information]. The blade profile is an Archimedean spiral, with the following specific parameters: small end diameter D1, large end diameter D2, number of blades N, pitch P, and axial length of the runner L.

[0064] The spiral turbine runner is connected to the built-in motor via a shaft, and its radial and axial displacement is constrained by bearings.

[0065] In this embodiment, the circulation pipeline, in addition to being connected to the bidirectional test section of the turbine via a connecting flange, is also connected upstream to the upstream water tank, and the pipeline diameter is [missing information]. The downstream end is connected to the downstream water tank, and the pipe diameter is [missing information]. The transition point between the upstream and downstream pipe diameters is located on the upstream side of the bidirectional test section of the turbine.

[0066] In this embodiment, the upstream water tank includes a storage tank, a return tank, and a water level overflow plate; the water level overflow plate includes two stationary plates and one movable plate, used to separate the storage tank and the return tank; the water level in the storage tank can be adjusted by moving the movable plate up and down; the diameter of the pipe upstream of the circulation pipeline on the side of the storage tank is... The pipes are connected, and the bottom pipe is connected to the water supply pump in the downstream water tank. The water supply pump draws water from the downstream water tank and pumps it to the storage tank to achieve water circulation in the test device. The bottom of the return tank has a pipe connected to the downstream water tank. Water overflowing from the storage tank is collected in the return tank and flows back to the downstream water tank through the bottom pipe to stabilize the water level in the storage tank.

[0067] In this embodiment, the circulation pipeline between the upstream water tank and the bidirectional test section of the turbine is also connected to a flow valve; the flow valve can control the flow rate entering the bidirectional test section of the turbine by adjusting its opening.

[0068] In this embodiment, the downstream water tank includes a storage tank, a dike baffle, a water-passing grid, and a water supply pump. The storage tank is fixed to the lower part of the structural steel frame, and its volume is not less than twice the volume of the upstream storage tank. It is used to store circulating water during normal operation of the test device. The water-passing grid is arranged in the storage tank and is located between the outlet of the downstream circulation pipeline and the dike baffle to stabilize the water flow through the dike baffle. The dike baffle has a rectangular cross-section and a water-passing width of B. After the water flow forms a stable flow through the dike baffle, the flow rate can be realized according to the following formula. Measurement:

[0069]

[0070]

[0071] In the formula: m is the flow coefficient of the cofferdam diaphragm, which can be determined experimentally; k is the contraction coefficient of the water tongue at the top of the weir. The velocity coefficient of the weir; is the ratio of the average pressure head to the total head at the weir crest cross section; g is the local gravitational acceleration; H0 is the dynamic pressure head upstream of the cofferdam diaphragm.

[0072] Example 2:

[0073] like Figure 8 As shown, the control method for the bidirectional spiral turbine hydraulic test device described above includes the following steps:

[0074] Step 1: The water supply pump starts running, pumping water from the downstream water tank to the upstream water tank;

[0075] Step 2: Adjust the water level overflow plate to the specified height H, and open the flow valve to the specified opening degree. The flow rate can be measured once based on the relationship curve between the valve flow coefficient and the valve opening. Part of the water flow in the upstream tank enters the bidirectional test section of the turbine through the circulation pipeline, while another part flows out through the overflow plate and then enters the downstream tank through the return tank. The formula for calculating the flow rate in one measurement is as follows:

[0076]

[0077] In the formula: C v Where is the valve's flow coefficient; N1 is a constant, taken as 0.0865; F p This is the pipeline geometry coefficient, which is set to 1 when the control valve diameter matches the pipeline diameter. P v The static pressure difference of the valve; This represents the density of the fluid under the current pressure and temperature conditions. This is the density of water at 15℃.

[0078] Step 3: The bidirectional test section of the water turbine is submerged in the water flow. The built-in motor controller controls the motor to drive the spiral water turbine to run at a specified speed, and monitors signal parameters such as shaft torque T and speed n.

[0079] Step 4: After passing through the bidirectional test section, the water flows into the downstream water tank through the downstream circulation pipeline. After being stabilized by the water grid, it further flows through the cofferdam baffle. After reading the water level height upstream of the cofferdam baffle, the flow rate can be measured a second time using the following formula:

[0080]

[0081]

[0082] In the formula, m is the flow coefficient of the cofferdam diaphragm, which can be determined experimentally; k is the contraction coefficient of the water tongue at the top of the weir. The velocity coefficient of the weir; is the ratio of the average pressure head to the total head at the weir crest cross section; g is the local gravitational acceleration; H0 is the dynamic pressure head upstream of the cofferdam diaphragm.

[0083] Step 5: The control component compares the results of the first and second flow measurements. If the relative error of the flow is within 5%, the average of the first and second flow measurements is taken as the flow rate Q. Otherwise, the test conditions should be repeated.

[0084] Step 6: After obtaining parameters such as head H, flow rate Q, torque T, and rotational speed n under a certain test condition, the efficiency of the screw turbine under the current condition can be determined. The calculation is performed using the following formula:

[0085]

[0086] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

[0087] Many other changes and modifications can be made without departing from the concept and scope of this invention. It should be understood that this invention is not limited to the specific embodiments, and the scope of this invention is defined by the appended claims.

Claims

1. A hydraulic testing device for a bidirectional spiral turbine, characterized in that, The device includes: a downstream water tank (3), a circulation pipeline (4), a two-way test section of a water turbine (5), and a control component (6); an upstream water tank (2) is set on the top of the downstream water tank (3), and the upstream water tank (2) and the downstream water tank (3) are connected through the circulation pipeline (4). The circulation pipeline (4) is equipped with a two-way test section of a water turbine (5), and a spiral water turbine runner (5-1) is set in the two-way test section of the water turbine (5). When the water turbine hydraulic test device is running, the control component (6) controls the head, flow rate and rotation speed of the spiral water turbine runner (5-1) entering the two-way test section of the water turbine (5) to realize the change of the working conditions of the test device. The circulation pipeline (4) between the upstream water tank (2) and the bidirectional test section (5) of the turbine is connected to a flow valve (6-2); the flow valve (6-2) can control the flow rate entering the bidirectional test section (5) of the turbine by adjusting the opening degree; The downstream water tank (3) includes a water storage tank (3-1), a dike partition (3-2), a water flow grid (3-3), and a water supply pump (6-4). The water storage tank (3-1) is fixed to the lower part of the structural steel frame (1). The volume of the water storage tank is not less than twice the volume of the upstream water storage tank. It is used to store the circulating water during normal operation of the test device. The cofferdam partition (3-2) and the water-passing grid (3-3) are both arranged in the water storage tank (3-1). The water-passing grid (3-3) is distributed between the outlet of the downstream circulation pipeline and the cofferdam partition (3-2) to stabilize the water flow through the cofferdam partition (3-2). The cofferdam partition (3-2) has a rectangular cross-section and a water passage width of B. After the water flows through the cofferdam partition (3-2) and forms a stable flow, the flow rate can be calculated according to the following formula. Measurement: ， ， In the formula: m is the flow coefficient of the cofferdam diaphragm, which can be determined experimentally; k is the contraction coefficient of the water tongue at the top of the weir. The velocity coefficient of the weir; is the ratio of the average pressure head to the total head at the weir crest cross section; g is the local gravitational acceleration; H0 is the dynamic pressure head upstream of the cofferdam diaphragm. The water supply pump (6-4) is a submersible pump. Its inlet end is submerged below the water surface of the water storage tank (3-1), and its outlet end is connected to the bottom pipe of the water storage tank (2-1) to pump the water in the downstream water tank (3) to the upstream water tank (2). When the hydraulic test device for the spiral turbine is running in the forward direction, the small end of the spiral turbine runner (5-1) faces the upstream flow; when the hydraulic test device for the spiral turbine is running in the reverse direction, the large end of the spiral turbine runner (5-1) faces the upstream flow. When the spiral turbine hydraulic test device switches between forward and reverse operation, the test device is in a stopped state. Loosen the connecting bolts of the connecting flanges at both ends of the turbine bidirectional test section (5), rotate the turbine bidirectional test section (5) 180° and then tighten the installation to realize the bidirectional switching of the hydraulic test device. The control component (6) includes: a water level overflow plate (6-1) installed in the upstream water tank (2), a flow valve (6-2) installed in the circulation pipeline (4), a motor controller (6-3) installed in the bidirectional test section (5) of the turbine, and a water supply pump (6-4) installed in the downstream water tank (3).

2. The hydraulic testing device for a bidirectional spiral turbine according to claim 1, characterized in that, Also includes: Structural steel frame (1) is used to support and fix the upstream water tank (2), the downstream water tank (3), the circulation pipeline (4), the bidirectional test section of the turbine (5), and the control components (6).

3. The hydraulic testing device for a bidirectional spiral turbine according to claim 1, characterized in that, The bidirectional test section (5) of the water turbine includes: a spiral water turbine runner (5-1), an external pipeline (5-2), guide vanes (5-3), and an internal motor (5-4). The external pipeline (5-2) is connected to the external support plate of the internal motor (5-4). The two sides of the test section are connected to the circulation pipeline (4) through flanges. The axis of the water turbine coincides with the horizontal center line of the upstream and downstream circulation pipelines. The spiral turbine runner (5-1) includes a hub and blades. The hub is conical and horizontally positioned, with a diffusion angle of [missing information]. The blade profile is an Archimedean spiral, with the following specific parameters: small end diameter D1, large end diameter D2, number of blades N, pitch P, and axial length of the runner L. The spiral turbine runner (5-1) is connected to the built-in motor (5-4) via a shaft, and its radial and axial displacement is constrained by bearings.

4. The hydraulic testing device for a bidirectional spiral turbine according to claim 1, characterized in that, The upstream end of the circulation pipeline (4) is connected to the upstream water tank (2), and the pipeline diameter is... The downstream end is connected to the downstream water tank (3), and the pipe diameter is... The upstream pipe diameter With downstream pipe diameter The transition position is on the upstream side of the bidirectional test section (5) of the water turbine.

5. The hydraulic testing device for a bidirectional spiral turbine according to claim 1, characterized in that, The upstream water tank (2) includes: a water storage chamber (2-1), a return flow chamber (2-2), and a water level overflow plate (6-1). The water level overflow plate (6-1) includes two stationary plates and one movable plate, which are used to separate the water storage chamber (2-1) and the return chamber (2-2); the water level in the water storage chamber (2-1) can be adjusted by moving the movable plate up and down. The diameter of the side of the water storage cavity (2-1) and the upstream of the circulation pipe (4) is... The pipeline is connected, and the bottom pipeline of the water storage chamber (2-1) is connected to the water supply pump (6-4) in the downstream water tank; the water supply pump (6-4) realizes the water circulation of the test device by drawing water from the downstream water tank and pumping it into the water storage chamber (2-1); The bottom of the return cavity (2-2) is connected to the downstream water tank (3) through a pipeline. The water overflowing from the water storage cavity (2-1) is collected by the return cavity (2-2) and flows back to the downstream water tank (3) through the bottom pipeline to stabilize the water level in the water storage cavity (2-1).

6. A hydraulic test control method for a bidirectional spiral turbine, characterized in that, The method is applied to a bidirectional spiral turbine hydraulic test device as described in any one of claims 1-5, and the method includes: Step 1: The water supply pump (6-4) is started and runs to send water from the downstream water tank (3) to the upstream water tank (2). Step 2: Adjust the water level overflow plate (6-1) to the specified height H, and open the flow valve (6-2) to the specified opening degree. The flow rate can be measured once based on the relationship curve between the valve flow coefficient and the valve opening. Part of the water in the upstream tank (2) flows into the bidirectional test section (5) of the turbine through the circulation pipeline (4), and part of the water flows out through the water level overflow plate (6-1) and then enters the downstream tank (3) through the return cavity (2-2). The formula for calculating the flow rate once is as follows: ， In the formula: C v Where is the valve's flow coefficient; N1 is a constant, taken as 0.0865; F p This is the pipeline geometry coefficient, which is set to 1 when the control valve diameter matches the pipeline diameter. P v The static pressure difference of the valve; This represents the density of the fluid under the current pressure and temperature conditions. The density of water at 15℃; Step 3: The bidirectional test section (5) of the water turbine is submerged in the water flow. The built-in motor controller (5-4) controls the motor to drive the spiral water turbine runner (5-1) to run at the specified speed, and monitors the shaft torque T and speed n signal parameters. Step 4: After the water flows through the bidirectional test section (5) of the turbine, it enters the downstream water tank (3) through the downstream circulation pipeline (4). After the water flows steadily through the water grid (3-3), it flows further through the cofferdam baffle (3-2). After reading the water level height upstream of the cofferdam baffle (3-2), the flow rate is measured a second time using the following formula: ， ， In the formula, m is the flow coefficient of the cofferdam diaphragm (3-2), which can be determined experimentally; k is the contraction coefficient of the water tongue at the top of the weir. The velocity coefficient of the weir; is the ratio of the average pressure head to the total head at the weir crest cross section; g is the local gravitational acceleration; H0 is the dynamic pressure head upstream of the cofferdam diaphragm. Step 5: The control component (6) compares the first and second flow measurement results. If the relative error of the flow is within 5%, the average of the first and second flow measurement results is taken as the flow rate Q. Otherwise, the test condition should be repeated. Step six: After obtaining the parameters of head H, flow rate Q, torque T, and speed n under the test conditions, determine the efficiency of the screw turbine under the current operating conditions. The calculation is performed using the following formula: 。

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