A stirred process pressure measurement device and method

Abstract

The application discloses a stirring process pressure measuring device and method, and relates to the technical field of pressure measurement.The device comprises an experimental cylinder body, a digital acquisition instrument and a computer, wherein the experimental cylinder body comprises a stirring barrel main body and a pressure conduction cavity which are separated by a partition plate, and the bottom of the pressure conduction cavity is further connected with a pressure transmitter for measuring the pressure of a set measuring hole; the digital acquisition instrument is connected with the pressure transmitter and is used for collecting the pressure of multiple measuring holes; the computer is connected with the digital acquisition instrument and is used for calculating the flow rate of the pressure of the stirring process according to the pressure of each measuring hole, and drawing the pressure field distribution and the velocity field distribution in the stirring barrel main body based on the calculation result.The application can collect pressure signals by means of the cylinder side wall and the bottom transmitter, and realize the pressure measurement at any position in a three-dimensional space.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure measurement, in particular to a stirring process pressure measurement device and method. BACKGROUND

[0002] The current stirring equipment is an indispensable key equipment in many industries such as chemical industry, construction, and pharmaceutical industry, and its performance is directly related to production efficiency and product quality. In the traditional stirring equipment, the design of the impeller mostly adopts the classic structure, which has certain gap in stirring and mixing efficiency and energy consumption compared with the new type of impeller, so it is necessary to measure the pressure at different positions to analyze the single-phase and two-phase flow conditions inside the stirring device.

[0003] However, the measurement means for pressure distribution in the stirring process in the prior art is relatively limited, mostly relying on experience estimation or simple sensor configuration, and these methods often cannot accurately capture the complex three-dimensional fluid pressure field and velocity field distribution inside the stirring equipment. Especially at key positions such as the side wall and the bottom, there is a lack of precise pressure measurement point arrangement, resulting in insufficient comprehensive and in-depth monitoring and analysis of the fluid flow state. SUMMARY

[0004] The purpose of the present application is to provide a stirring process pressure measurement device and method, which can collect pressure signals by using the side wall and bottom transducer of the cylinder, and realize pressure measurement at any position in three-dimensional space.

[0005] To achieve the above purpose, the present application provides the following scheme:

[0006] A stirring process pressure measurement device, comprising:

[0007] An experimental cylinder, comprising a stirring barrel main body and a pressure conduction cavity separated by a partition plate, and the bottom of the pressure conduction cavity is further connected with a pressure transmitter for measuring the pressure of a set measurement hole;

[0008] A digital acquisition instrument connected with the pressure transmitter for collecting the pressure of multiple measurement holes;

[0009] A computer connected with the digital acquisition instrument for calculating the flow rate of the stirring process according to the pressure of each measurement hole, and drawing the pressure field distribution and velocity field distribution inside the stirring barrel main body based on the calculation result.

[0010] Optionally, a rubber ring is further arranged between the stirring barrel main body and the pressure conduction cavity for sealing, and the stirring barrel main body in the upper layer and the pressure conduction cavity in the lower layer are combined with the partition plate through a flange.

[0011] Optionally, the stirring barrel body comprises a barrel, a speed regulation motor, baffles, a stirring shaft and an impeller connected with the stirring shaft; the stirring shaft and the impeller are arranged in the barrel, and a plurality of baffles are arranged on the side wall of the barrel; the stirring shaft is further connected with the speed regulation motor.

[0012] Optionally, the pressure transmitter is further connected with a 24V DC power supply.

[0013] Optionally, the measuring holes comprise a first measuring hole group and a second measuring hole group; the first measuring hole group is arranged on the partition plate, and the second measuring hole group is arranged on the side wall of the barrel wall.

[0014] The application further provides a stirring process pressure measurement method based on the above device, comprising:

[0015] The measurement device is inspected, and the pressure transmitter is calibrated;

[0016] After the inspection and the calibration are completed, the pressure of the plurality of measuring holes is measured respectively to obtain a plurality of groups of data, the flow rate is calculated based on each group of data, and the pressure field distribution and the velocity field distribution in the stirring barrel body are plotted based on the calculation result.

[0017] Optionally, the inspection process comprises:

[0018] The sealing condition of the partition plate and the upper and lower rubber rings in the barrel is checked, whether there is water leakage at the connection of the bottom transmitter is checked, and whether there is liquid leakage at the valve connection and downstream of the valve under the closed state of the drain valve is checked;

[0019] After the water is discharged, a bubble level is placed on the partition plate in the barrel, the height of the four corners of the stirring barrel support is adjusted, the stirring barrel body is kept horizontally placed, a scale is placed at each baffle after water is injected into the barrel, the liquid height readings are checked to be equal, and the horizontal placement of the barrel is verified;

[0020] The impeller, the stirring shaft and the speed regulation motor are connected and installed in the stirring barrel, a bubble level is placed on the top of the motor to adjust the stirring shaft to be perpendicular to the liquid surface, the distance of the stirring shaft from the barrel wall in four directions is measured, and the motor support is adjusted to make the stirring shaft be located in the center of the barrel as much as possible;

[0021] Before the experiment starts, water is injected into the bottom cavity, to avoid air bubbles in the cavity, the partition plate and the upper barrel are first removed, water is added to the lower pressure transmission cavity, the water is added until the liquid surface overflows from the lower rubber ring, then the partition plate is tilted from one side to completely discharge the air from the other side;

[0022] The pressure transmitter is connected with the DC power supply and the digital acquisition instrument, then water is added to the barrel, the voltage reading change is observed, and then the calibration of the pressure transmitter is performed.

[0023] Optionally, the process of calibration specifically comprises:

[0024] First, fill the cylinder with water to a certain height h, because the cylinder is an open container, then calculate the theoretical hydrostatic pressure caused by the liquid level, and fit the slope and intercept values of the actual performance curve of the pressure transmitter, thereby completing the calibration.

[0025] Optionally, the process of measurement specifically comprises:

[0026] Step 1: Close measuring points 2-5 with hot melt glue, open measuring point 1, add water to the cylinder, read the level, and add to the liquid level of 270 mm, and record the readings of the data acquisition instrument at this time as the liquid level reference;

[0027] Step 2: Set the speed motor speed to 300 rpm, the data acquisition sampling interval to 0.1 s, and set the sampling to stop automatically after 1200 times, i.e. the sampling time is 120 s; Set the sampling start time, manually start the stirring motor according to the computer stopwatch when the set time is reached, at which time the sampling automatically starts, the motor is turned off after the sampling is completed, and the pressure data is exported;

[0028] Step 3: Wait for 1 min, and repeat step 2 after the liquid level is restored;

[0029] Step 4: When measuring point 1 is completed, open the water drain valve to empty the water in the upper cylinder, open measuring point 2, and close the remaining measuring points. After changing the measuring point, check whether there are air bubbles in the cavity, keep the cavity completely filled with water, fill water into the upper cylinder, and after the water reaches 270 mm, observe the readings of the data acquisition instrument, and adjust the liquid level to the liquid level reference in step 1; Repeat steps 2-3 to finally complete the measurement of all 5 measuring points;

[0030] Step 5: Process the pressure fluctuation data of the 5 measuring points, select the measuring point 3 with smaller fluctuation, open the measuring point 3, and close the remaining measuring points, and measure the pressure under different speeds in single phase. Since the speed motor needs a certain start-up time from start-up to reach the set speed, it takes about 35 s at 300 rpm, about 45 s at 400 rpm, and about 55 s at 500 rpm. Extend the sampling time to 150 s, so that the effective sampling time after reaching the set speed is greater than 90 s under all speeds.

[0031] Step 6: Set the speed to 300 rpm, 400 rpm, and 500 rpm respectively, and repeat steps 2-3, measuring 3 times at each speed;

[0032] Step 7: Replace the installed impeller and check the installation height of the impeller, keep the distance from the bottom constant at 90 mm, and repeat steps 2-6 to finally obtain multiple sets of data for different impellers.

[0033] Optionally, the formula of the flow rate calculation is:

[0034]

[0035] In the formula, v i is the total velocity of the measuring point i, m / s; p i-底 is the pressure of the measuring point i corresponding to the bottom, Pa; p i-静 is the pressure of the measuring point i, Pa; h i is the vertical distance of the measuring point i from the bottom, m; and p is the fluid density, kg / m 3 .

[0036] According to the specific embodiments provided by the application, the following technical effects are disclosed:

[0037] The application discloses a stirring process pressure measuring device and method, the device comprises an experimental cylinder, a digital acquisition instrument and a computer, wherein the experimental cylinder comprises a stirring barrel main body and a pressure conduction cavity which are separated by a partition plate, and the bottom of the pressure conduction cavity is further connected with a pressure transmitter for measuring the pressure of a set measuring hole; the digital acquisition instrument is connected with the pressure transmitter and is used for collecting the pressure of multiple measuring holes; the computer is connected with the digital acquisition instrument and is used for calculating the flow rate of the pressure of the stirring process according to the pressure of each measuring hole, and drawing the pressure field distribution and the velocity field distribution in the stirring barrel main body based on the calculation result. The device can collect pressure signals by the bottom transmitter and the side wall of the cylinder, and realize pressure measurement at any position in three-dimensional space. The device can arrange pressure measuring points on the side wall and the bottom of the stirring equipment, establish the relationship between the pressure and the fluid flow rate, obtain the three-dimensional fluid velocity field and the pressure field distribution in the stirring equipment, and thus provide a reference for two-phase mixing degree analysis and stirring device performance evaluation. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0039] Figure 1 It is a structural schematic diagram of the stirring process pressure measuring device of the present application;

[0040] Figure 2 It is a stirring cylinder structure size and measuring point opening position schematic diagram in the present embodiment; wherein, the part (a) is a cylinder opening schematic diagram; the part (b) is a partition plate measuring point position and cylinder size schematic diagram;

[0041] Figure 3 The logical diagram of the stirring process pressure measurement method of the present application.

[0042] Reference numerals: 1, speed regulating motor; 2, baffle; 3, stirring shaft; 4, impeller; 5, cylinder; 6, partition; 7, pressure transmission cavity; 8, pressure transmitter; 9, measuring hole; 10, direct current power supply; 11, digital acquisition instrument; 12, computer. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0044] The present application aims to provide a stirring process pressure measurement device and method, which can collect pressure signals by using cylinder side wall and bottom transmitter, and realize pressure measurement at any position in three-dimensional space.

[0045] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0046] As shown in Figure 1 The present application provides a stirring process pressure measurement device, which comprises:

[0047] The experimental cylinder 5 comprises a stirring barrel body and a pressure transmission cavity 7 separated by a partition 6, and the bottom of the pressure transmission cavity 7 is further connected with a pressure transmitter 8 for measuring the pressure of the set measuring hole 9.

[0048] The digital acquisition instrument 11 is connected with the pressure transmitter 8, and is used for collecting the pressure of multiple measuring holes 9.

[0049] The computer 12 is connected with the digital acquisition instrument 11, and is used for calculating the flow rate of the stirring process pressure according to the pressure of each measuring hole 9, and drawing the pressure field distribution and velocity field distribution in the stirring barrel body based on the calculation result.

[0050] Wherein, the impeller 4 is connected to the speed regulating motor 1 through the stirring shaft 3, and the pressure transmitter 8 is installed at the bottom of the cylinder 5. The cavity is arranged at the bottom of the cylinder 5 to transmit the pressure of the measuring point to the bottom transmitter, so that the transmitter does not need to be disassembled and moved when the measuring point is replaced, and the sealing of the interface is ensured. When measuring the pressure of a measuring point, the remaining measuring points are plugged, and when the measuring point needs to be changed, the plugging point can be changed. The DC power supply 10 outputs 24V DC power to supply power to the pressure transmitter 8. The transmitter converts the measured pressure signal into a voltage signal, which is collected by the digital acquisition instrument 11 and recorded and displayed in real time in the software of the computer 12.

[0051] The upper layer of the experimental cylinder 5 is the stirring cylinder main body, the lower layer is the pressure transmission cavity 7, and the middle is separated by the partition plate 6. The upper and lower layers and the partition plate 6 are combined through the flanges. The bottom plate is provided with holes for measuring points 1-5, and the side of the cylinder wall is provided with holes for measuring points 6-10, a total of 10 measuring points. The fluid pressure of the upper layer is transmitted to the cavity by opening a certain measuring point, and then transmitted to the pressure transmitter 8. When the measuring point is replaced, the remaining measuring points are closed with hot melt glue. The size of the cylinder 5 and the position of the measuring point hole on the partition plate 6 are shown in Figure 2

[0052] Then the pressure of each measuring point is collected, and according to the relationship between the dynamic pressure and the static pressure of the measuring point, the following can be obtained:

[0053] p i-静 +p i-动 +ρgh i =p i-底

[0054] Further:

[0055] p i-动 =p i-底 -p i-静 -ρgh i

[0056] Also:

[0057]

[0058] Finally, the speed of the intersection point of the horizontal plane of the measuring point i in the stirring cylinder and the vertical plane of the bottom measuring point can be obtained:

[0059]

[0060] In the formula, v i is the total speed of the measuring point i, m / s; p i-底 is the pressure of the measuring point i corresponding to the bottom, Pa; p i-静 is the pressure of the measuring point i, Pa; h i is the vertical distance of the measuring point i from the bottom, m; and ρ is the fluid density, kg / m 3 .​

[0061] Therefore, by the above formula, the fluid velocity at multiple points in the three-dimensional stirring cylinder can be obtained, and the velocity field distribution and pressure field distribution in the stirring cylinder can be drawn, which can provide data support for complex flow field analysis in the stirring process. The experimental detailed process is shown in Figure 3

[0062] 1. Experimental preparation

[0063] (1) Check the sealing condition of the cylinder 5 partition 6 and the upper and lower rubber ring, check whether there is water leakage at the bottom of the transmitter connection. Check the valve connection and the downstream of the valve under the closed state of the drain valve, there is no liquid seepage.

[0064] (2) After draining the water, place the bubble level on the cylinder partition 6, adjust the height of the four corners of the stirring cylinder support, and make the cylinder as horizontal as possible. After filling water in the cylinder, place the scale at the four baffles 2 respectively, check the equal liquid height reading, and verify the horizontal placement of the cylinder 5.

[0065] (3) Connect the impeller 4, stirring shaft 3 and motor, install in the stirring cylinder. Place the bubble level on the top of the motor to adjust the stirring shaft 3 perpendicular to the liquid surface. Measure the distance of the stirring shaft 3 from the four directions of the cylinder wall, adjust the motor support to make the stirring shaft 3 as close to the center of the cylinder 5 as possible.

[0066] (4) Before starting the experiment, fill water in the bottom cavity. In order to avoid air bubbles in the cavity, first remove the partition 6 and the upper cylinder 5, and add water at the bottom. Add water until the liquid surface overflows from the lower rubber ring, then tilt from one side to cover the partition 6 from the other side, so as to completely discharge the air from the other side.

[0067] (5) Connect the pressure transmitter 8 with the power supply and digital acquisition instrument 11, then add water to the cylinder, and the voltage reading can be observed. Then calibrate the pressure transmitter 8.

[0068] 2. Calibration of pressure transmitter 8

[0069] The water pressure at the bottom of the stirring cylinder is converted into voltage signal by the pressure transmitter 8, and is restored to pressure signal after being collected and processed by the computer 12. The pressure range of the transmitter is 0-5kPa, and the sensor outputs voltage signal 0-10V. Under ideal conditions, the conversion of voltage signal and pressure signal is linear, that is, P=1 / 2V can restore the pressure signal. However, in practical application, due to the influence of environmental temperature, gravity acceleration and other factors, the transmitter may have zero point deviation and other conditions, so the transmitter needs to be calibrated to eliminate such errors.

[0070] First, fill water in the stirring cylinder to a certain height h. Since the cylinder 5 is an open container, the theoretical hydrostatic pressure brought by the liquid surface height at this time can be calculated by P i ​= pgh. The actual performance curve of the transmitter is V = aP + s. The slope a and intercept s can be fitted by calculating the values at several heights. The fitted values are a = 1.9854, s = 0.18034.

[0071] Table 1 Calibration points of pressure transmitter 8

[0072]

[0073]

[0074] The Pearson correlation coefficient r = 0.99933 and R2= 0.99866 of the fitted straight line. According to Table 1, the measurement error of the upper cylinder when filled with water is less than 2% after calibration.

[0075] 3. Experimental operation

[0076] (1) Close measuring points 2-5 and open measuring point 1. Add water to the cylinder, read the level, and record the reading of the data acquisition instrument at this time as the level height reference.

[0077] (2) Set the speed of the speed-regulating motor 1 to 300 rpm and the data acquisition sampling interval to 0.1 s. Set the sampling to stop automatically after 1200 times, i.e. the sampling time is 120 s. Set the sampling start time to an appropriate time, manually start the stirring motor when the computer reaches the set time, at which time the sampling starts automatically, the motor is turned off after sampling, and the pressure data is exported.

[0078] (3) Wait for 1 min, and repeat step 2 after the liquid level is restored.

[0079] (4) After measuring point 1 is completed, open the water drain valve to empty the water in the upper cylinder. Open measuring point 2 and close the remaining measuring points. After changing the measuring point, check whether there are air bubbles in the cavity, and keep the cavity completely filled with water. Add water to the upper cylinder, and after the water reaches 270 mm, observe the reading of the data acquisition instrument, and adjust the liquid level to the reference level in step 1. Repeat steps 2-3. Finally, complete the measurement of all 5 measuring points.

[0080] (5) Process the pressure fluctuation data of the 5 measuring points, and select the measuring point 3 with smaller fluctuation. Open measuring point 3 and close the remaining measuring points, and measure the pressure at different speeds in single phase. Since the speed-regulating motor 1 needs a certain start-up time from start-up to reach the set speed, it takes about 35 s at 300 rpm, about 45 s at 400 rpm, and about 55 s at 500 rpm. Extend the sampling time to 150 s, so that the effective sampling time after reaching the set speed is greater than 90 s at all speeds.

[0081] (6) Set the rotating speed to 300 rpm, 400 rpm, 500 rpm respectively, repeat steps 2-3, and measure 3 times under each rotating speed.

[0082] (7) Replace the assembled impeller 4, and check the installation height of the impeller 4, keep the distance from the bottom to be 90 mm unchanged. Repeat steps 2-6. Finally, multiple sets of data are obtained for different impellers 4, as shown in Table 2. Among them, o is three sets of repeated measurement data.

[0083] Table 2 Single-phase stirring measurement

[0084]

[0085] Therefore, the present application has the following advantages and remarkable effects:

[0086] (1) The prior art can only measure the pressure at a single position in the cylinder 5, and cannot realize pressure measurement at any position in three-dimensional space. The present application uses the side wall and bottom transducer of the cylinder 5 to collect pressure signals, which can monitor the pressure fluctuation at any position in the stirring process in real time, and can also analyze the pressure change trend on any cross section, which is quite important for performance evaluation and guidance of the stirring device; (2) Avoiding calculation errors and subjective factors caused by using empirical correlation formula, it has good adaptability to different stirring equipment sizes and stirring power and other working conditions.

[0087] Each embodiment in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between each embodiment can be referred to each other.

[0088] The principles and implementation modes of the present application are described by applying specific examples in this paper, and the above embodiment description is only used to help understand the core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In view of the above, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A stirred process pressure measurement device, characterized by, The utility model relates to a kind of experimental stirring barrel and its measurement method, including: Experimental cylinder, including stirring barrel main body and pressure transmission cavity separated by partition, and the bottom of the pressure transmission cavity is also connected with pressure transmitter, for measuring the pressure of setting measuring hole; Digital acquisition instrument, connected with the pressure transmitter, for collecting the pressure of multiple measuring holes; Computer, connected with the digital acquisition instrument, for calculating the flow rate of pressure in stirring process according to the pressure of each measuring hole, and drawing the pressure field distribution and velocity field distribution in stirring barrel main body based on the calculation result.

2. The stirred process pressure measurement apparatus of claim 1, wherein, The stirring barrel main body and the pressure transmission cavity are also sealed by rubber ring, and the upper stirring barrel main body and the lower pressure transmission cavity are combined with the partition through flange.

3. The stirred process pressure measurement apparatus of claim 1, wherein, The stirring barrel main body, specifically includes: cylinder, speed regulating motor, baffle, stirring shaft and impeller connected with the stirring shaft;The stirring shaft and the impeller are arranged in the cylinder, and a plurality of baffles are arranged on the side wall of the cylinder;The stirring shaft is also connected with the speed regulating motor.

4. The stirred process pressure measurement apparatus of claim 1, wherein, The pressure transmitter is also connected with 24V DC power supply.

5. The stirred process pressure measurement apparatus of claim 1, wherein, The measuring hole includes first measuring hole group and second measuring hole group;The first measuring hole group is arranged on the partition, and the second measuring hole group is arranged on the side wall of the cylinder wall.

6. A method of measuring pressure in a stirred process based on the apparatus of any one of claims 1-5, characterized by, Including: Verify the measuring device, and calibrate the pressure transmitter; After the verification and calibration are completed, the pressure of multiple measuring holes is measured respectively to obtain multiple groups of data, and the flow rate is calculated based on each group of data, and the pressure field distribution and velocity field distribution in the stirring barrel main body are drawn based on the calculation result.

7. The stirred process pressure measurement method of claim 6, wherein, The verification process specifically includes: Check the sealing condition of the partition and the upper and lower rubber rings in the cylinder, check whether there is water leakage at the connection of the bottom transmitter, and check whether there is liquid leakage at the valve connection and downstream of the valve under the closed state of the drain valve; After draining water, place a bubble level on the partition in the cylinder, adjust the height of the four corners of the stirring cylinder support to keep the stirring barrel main body horizontally placed, place a scale at each baffle after filling water in the cylinder, check the equal liquid height reading, and verify the horizontal placement of the cylinder; Connect the impeller, stirring shaft and speed regulating motor, and install them in the stirring cylinder, place a bubble level on the top of the motor to adjust the stirring shaft perpendicular to the liquid surface, measure the distance between the stirring shaft and the cylinder wall in four directions, and adjust the motor support to make the stirring shaft as close to the center of the cylinder as possible; Before the experiment starts, fill water in the bottom cavity, to avoid air bubbles in the cavity, first remove the partition and the upper cylinder, add water to the lower pressure transmission cavity, add water until the liquid surface overflows from the lower rubber ring, then tilt the partition from one side to completely discharge air from the other side; Connect the pressure transmitter with DC power supply and digital acquisition instrument, then add water to the cylinder, observe the voltage reading change, and then calibrate the pressure transmitter.

8. The stirred process pressure measurement method of claim 6, wherein, The calibration process specifically includes: First, fill water in the cylinder to a certain height h, since the cylinder is an open container, then calculate the theoretical hydrostatic pressure caused by the liquid level, and fit the slope and intercept value of the actual performance curve of the pressure transmitter to complete the calibration.

9. The stirred process pressure measurement method of claim 6, wherein, The measurement process specifically includes: Step 1: Use hot melt adhesive to seal measuring points 2 to 5, open measuring point 1, add water to the cylinder, read the liquid level while looking straight ahead, and add water until the liquid level reaches 270 mm. Record the reading on the data logger at this point as the liquid level reference. Step 2: Set the speed of the speed regulating motor to 300 rpm, the sampling interval to 0.1 s, and set the automatic stop after 1200 samplings, that is, the sampling time is 120 s; set the sampling start time, and according to the computer stopwatch, manually start the stirring motor when the set time is reached. At this time, sampling automatically starts. After sampling, turn off the motor and export the pressure data; Step 3: Wait for 1 minute until the liquid surface returns to calm, then repeat step 2 and measure each measuring point 3 times. Step 4: After measuring point 1 is completed, open the drain valve to drain the water in the upper tube, open measuring point 2, and close the remaining measuring points. After changing the measuring point, check whether there are bubbles in the cavity. Keep the cavity fully filled with water and fill the upper tube with water. After the water filling reaches 270mm, observe the data logger reading and fine-tune the liquid level to the liquid height reference in step 1. Repeat steps 2 to 3 to complete the measurement of all 5 measuring points. Step 5: Process the pressure fluctuation data of the five measuring points. Select measuring point 3 with the smallest fluctuation, open measuring point 3, and close the other measuring points to measure the pressure at different speeds in single-phase operation. Since the speed regulating motor requires a certain startup time from starting to reaching the set speed, which is about 35 seconds at 300 rpm, about 45 seconds at 400 rpm, and about 55 seconds at 500 rpm, the sampling time is extended to 150 seconds so that the effective sampling time after reaching the set speed is greater than 90 seconds at all speeds. Step 6: Set the speed to 300 rpm, 400 rpm, and 500 rpm respectively, repeat steps 2 and 3, and measure 3 times at each speed; Step 7: Replace the impeller and check the installation height of the impeller, keeping the net distance from the bottom at 90mm. Repeat steps 2 to 6 to obtain multiple sets of data for different impellers.

10. The stirred process pressure measurement method of claim 6, wherein, The formula for calculating the flow rate is: Where, v i is the total velocity of the measuring point i, m / s; p i-底 is the pressure of the measuring point at the bottom corresponding to measuring point i, Pa; p i-静 is the pressure at measuring point i, Pa; h i is the vertical distance from measuring point i to the bottom, m; ρ is the fluid density, kg / m 3 .

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