Nozzle baffle flow coefficient measuring device and method

Abstract

The invention discloses a nozzle baffle flow coefficient measuring device and method. The nozzle baffle flow coefficient measuring device comprises a gas source module, a fluid control module, a data acquisition module and an upper computer. The gas source module is used for providing a pressure stabilizing gas source; the fluid control module comprises a temperature sensor, a first pressure sensor, a mounting seat, a second pressure sensor and a flow sensor which are sequentially connected through a pipeline; the temperature sensor is communicated with the air outlet end of the air source module through a test tube; a to-be-tested nozzle baffle is detachably connected in the mounting seat; the data acquisition module is integrated with a temperature sensor, a first pressure sensor, a second pressure sensor and a flow sensor; and the upper computer is in communication connection with the data acquisition module for data interaction. According to the invention, a non-destructive measurement mode is utilized, so that the disassembly loss of equipment can be avoided, the debugging cost is saved by more than 30%, the research blank of the flow coefficient multivariable influence rule of the nozzle baffle mechanism is filled, and an experimental support is provided for a fluid control theory.

Description

Technical Field

[0001] The present invention relates to the field of fluid control technology, and more particularly to a device and method for measuring a nozzle baffle flow coefficient. Background Art

[0002] As a core component of fluid control systems, nozzle-flapper mechanisms are widely used in equipment such as pneumatic valve positioners and hydraulic servo systems. The flow coefficient, a key performance parameter, directly impacts the system's control accuracy and stability. However, existing technologies lack systematic research on how the flow coefficient varies with different apertures, supply pressures, and temperatures. This results in a lack of reliable theoretical basis for equipment design optimization, making it difficult to achieve high-precision control. Furthermore, existing technologies suffer from the following drawbacks:

[0003] Measurement limitations: The nozzle and baffle are assembled in a sealed housing. Direct measurement requires destroying the structure, resulting in inaccurate test results.

[0004] Parameter coupling effect: Existing devices do not consider the multi-dimensional coupling effect of temperature, gas supply pressure and aperture, and cannot fully characterize the variation of flow coefficient;

[0005] Lack of standardization: The lack of a universal test platform suitable for different apertures results in the reliance on experience in the sorting and performance verification of nozzle baffles to be tested, making it difficult to ensure processing consistency.

[0006] Therefore, how to provide a test device and its application method for measuring the small hole flow coefficient under different apertures, gas supply pressures and temperature conditions in the nozzle baffle mechanism is a problem that technical personnel in this field urgently need to solve. Summary of the Invention

[0007] In view of this, the present invention provides a device and method for measuring the flow coefficient of a nozzle baffle, which solves the problems in the prior art of measurement errors caused by structural damage, insufficient multi-working condition simulation capabilities, and poor aperture adaptability.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A nozzle baffle flow coefficient measuring device includes an air source module, a fluid control module, a data acquisition module and a host computer;

[0010] The gas source module is used to provide a stable pressure gas source; the fluid control module includes a temperature sensor, a first pressure sensor, a mounting base, a second pressure sensor, and a flow sensor connected in sequence through pipelines; the temperature sensor is connected to the gas outlet end of the gas source module through a test tube; a nozzle baffle to be tested is detachably connected to the mounting base;

[0011] The data acquisition module is data-connected to the temperature sensor, the first pressure sensor, the second pressure sensor, and the flow sensor; and the host computer is communication-connected to the data acquisition module for data exchange.

[0012] The beneficial effect of the technical solution of the present invention is that the gas source module is used to provide a stable pressure gas source, and the gas source pressure and temperature are obtained through the temperature sensor and the pressure sensor, so as to measure the small hole flow coefficient under different apertures, gas supply pressure and temperature conditions in the nozzle baffle mechanism.

[0013] Preferably, the air source module includes an air compressor, a filter, and a pressure reducing valve connected in sequence via a pipeline, wherein the pressure reducing valve is connected to the end of the test tube away from the temperature sensor. The air compressor continuously outputs air, the filter ensures the purity of the airflow, and the pressure reducing valve controls the output pressure of the airflow.

[0014] Preferably, the mounting base is provided with slots on both sides corresponding to the pipe openings on both sides, and the nozzle baffle to be tested is embedded in the slots. The nozzle baffle to be tested is embedded in the slots, which facilitates the replacement of nozzle baffles of different shapes and diameters to meet the flow coefficient measurement work of different types of nozzle baffles to be tested.

[0015] Preferably, a sealing gasket is embedded between the circumference of the nozzle baffle to be measured and the inner wall of the slot, which can ensure the sealing between the nozzle baffle to be measured and the mounting seat, thereby ensuring the effectiveness of the measurement structure.

[0016] Preferably, the flow sensor is a thermal gas mass flow meter with a range of 0-200 L / min, an accuracy of ±1% FS, and a built-in temperature compensation algorithm. The flow sensor has high detection accuracy and can ensure the accuracy of the data.

[0017] Preferably, the data acquisition module integrates a Kalman filter algorithm to fuse multi-sensor data and output a flow coefficient with a comprehensive error of ≤±0.8%, thereby improving measurement accuracy and reducing the time required for a single test to less than 5 minutes, ensuring measurement efficiency.

[0018] Preferably, the air supply pressure of the air compressor is 0.1-1.0 MPa, with a fluctuation rate of <±0.5%, to ensure the stability of the air source and enable the measurement process to proceed continuously and stably.

[0019] The present invention also provides a method for measuring the nozzle baffle flow coefficient, which uses the nozzle baffle flow coefficient measuring device in the above technical solution to measure the nozzle baffle flow, including the following steps:

[0020] S1. Close the air source module and embed the nozzle baffle to be tested into the mounting seat;

[0021] S2, assembling the temperature sensor, the first pressure sensor, the mounting base, the second pressure sensor, and the flow sensor in sequence;

[0022] S3. Adjust the gas source module to the target gas supply pressure and stabilize the pressure fluctuation;

[0023] S4. The data acquisition module collects the gas temperature, the pressure before and after the baffle of the nozzle to be tested, and the flow rate in real time, and calculates the flow coefficient according to the throttling formula.

[0024] The beneficial effect of the above technical solution is that it adopts a non-invasive, multi-parameter coupled flow coefficient measuring device to solve the problems of measurement errors caused by structural damage, insufficient multi-condition simulation capabilities and poor aperture adaptability in the existing technology.

[0025] Preferably, dynamic calibration is also included:

[0026] Apply a step pressure change at the target gas supply pressure and record the flow coefficient response curve;

[0027] If the response time is greater than 2s or the flow coefficient fluctuation range is greater than 1%, it is determined that the nozzle baffle to be tested has abnormal flow resistance.

[0028] Preferably, the flow coefficient determination method is applied on an industrial production line, including: setting a qualified threshold range for the flow coefficient, automatically sorting out the nozzle baffles that are out of tolerance for testing; writing the mapping relationship of flow coefficient-target gas supply pressure-gas temperature into the servo valve controller to achieve flow self-calibration.

[0029] It can be seen from the above technical solution that compared with the prior art, the present invention discloses a device and method for measuring the flow coefficient of a nozzle baffle, which obtains the gas source pressure and temperature through a temperature sensor and a pressure sensor, and can measure the flow coefficient of the small holes under different apertures, gas supply pressures and temperature conditions in the nozzle baffle mechanism; the present invention adopts high-precision sensors to ensure the reliability of the data; the use of non-destructive measurement methods can avoid equipment disassembly losses and save more than 30% of debugging costs; it fills the research gap in the multivariate influence law of the flow coefficient of the nozzle baffle mechanism and provides experimental support for fluid control theory. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0031] Figure 1 A schematic structural diagram of the measuring device provided by the present invention;

[0032] Figure 2 A schematic structural diagram of a fluid control module provided by the present invention;

[0033] Figure 3 This is a schematic diagram of the nozzle baffle structure to be tested provided by the present invention.

[0034] in,

[0035] 1-air source module; 11-filter; 12-pressure reducing valve; 2-test tube; 3-temperature sensor; 4-first pressure sensor; 5-mounting seat; 51-sealing gasket; 52-slot; 6-second pressure sensor; 7-flow sensor; 8-nozzle baffle to be tested; 9-data acquisition module; 10-host computer. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] Example 1:

[0038] Participate in the Figures 1 to 3 , the embodiment of the present invention discloses a nozzle baffle flow coefficient measuring device, including an air source module 1, a fluid control module, a data acquisition module 9 and a host computer 10;

[0039] The air source module 1 is used to provide a stable pressure air source; the fluid control module includes a temperature sensor 3, a first pressure sensor 4, a mounting base 5, a second pressure sensor 6, and a flow sensor 7 connected in sequence through pipelines; the temperature sensor 3 is connected to the air outlet of the air source module through a test tube 2; a nozzle baffle 8 to be tested is detachably connected to the mounting base 5;

[0040] The data acquisition module 9 is data-connected to the temperature sensor 3 , the first pressure sensor 4 , the second pressure sensor 6 and the flow sensor 7 ; the host computer 10 is communication-connected to the data acquisition module 9 for data exchange.

[0041] In this embodiment, the air source module 1 includes an air compressor, a filter 11 and a pressure reducing valve 12 which are sequentially connected through pipelines. The pressure reducing valve 12 is connected to the end of the test tube 2 away from the temperature sensor 3 .

[0042] like Figure 1As shown, an air compressor (not shown in the figure) is used to provide an air source, and a filter can filter the air source of the air compressor to ensure the purity of the gas entering the measuring tube. The air pressure entering the measuring tube can be controlled by a pressure reducing valve, and the pressure reducing valve can adjust different air pressures to achieve multi-working condition measurement.

[0043] In other specific embodiments, the filter is a precision filter, and the pressure reducing valve is a two-stage pressure reducing valve, including a first pressure reducing valve and a second pressure reducing valve connected in sequence, the second pressure reducing valve is connected to the test tube, and the output pressure adjustment range of the second pressure reducing valve is 0.1-1.0MPa, with an accuracy of 0.5 level. By adjusting the second pressure reducing valve, the air pressure entering the measuring tube can be controlled.

[0044] In order to further optimize the above technical solution and ensure measurement accuracy, the flow sensor 7 is a thermal gas mass flow meter with a range of 0-200L / min, an accuracy of ±1%FS, and a built-in temperature compensation algorithm. The air compressor supply pressure is 0.1-1.0MPa, with a fluctuation rate of <±0.5%;

[0045] The data acquisition module 9 integrates a Kalman filter algorithm to fuse multi-sensor data and output a flow coefficient with a comprehensive error of ≤±0.8%.

[0046] The data acquisition module of this embodiment supports the RS485 communication protocol and interacts with the host computer in real time.

[0047] In order to further optimize the above technical solution and realize the detachable connection of the nozzle baffle to be tested, slots 52 corresponding to the pipe openings on both sides are respectively opened on both sides of the mounting base 5, and the nozzle baffle to be tested 8 is embedded in the slots 52.

[0048] like Figure 2 Said mounting seat is provided with communicating slots on both sides, the nozzle baffle to be tested is a orifice plate, the periphery of the orifice plate is embedded in the slots and the openings on the orifice plate correspond to the gaps in the slots to ensure effective gas circulation.

[0049] In order to further optimize the above technical solution and ensure the sealing between the nozzle baffle to be tested and the mounting seat, a sealing gasket 51 is embedded between the circumference of the nozzle baffle to be tested 8 and the inner wall of the slot 52 .

[0050] The sealing gasket is a fluororubber sealing gasket with a hardness of Shore A70±5 and is installed on the inner wall of the groove.

[0051] In other specific embodiments, to ensure the sealing effect, a double-threaded fastener is further included for applying an axial sealing pressure of ≥2 MPa, and the nozzle baffle and sealing gasket to be tested are installed in the groove of the mounting seat through the double-threaded fastener.

[0052] In other specific embodiments, the length of the pipeline of the mounting base relative to the first pressure sensor is ≥10D (D is the pipe diameter), and the length of the pipeline of the mounting base relative to the second pressure sensor is ≥5D.

[0053] In actual operation, when the straightness of the pipeline cannot be guaranteed, the pipeline bending radius is greater than 3D and the bending angle is ≤30°.

[0054] In some other specific embodiments, the nozzle baffle to be tested may have many structural forms, including but not limited to changes in aperture, hole length, and flow structure of the nozzle baffle to be tested, and attention should be paid to the flow direction of different nozzle baffle forms to be tested.

[0055] Example 2:

[0056] The embodiment of the present invention discloses a method for measuring a nozzle baffle flow coefficient, which uses the nozzle baffle flow coefficient measuring device in Example 1 to measure the nozzle baffle flow rate, including the following steps:

[0057] S1. Close the air source module and embed the nozzle baffle to be tested into the mounting seat;

[0058] Insert the nozzle baffle to be tested (aperture tolerance ±0.01mm) into the center notch of the mounting seat along the medium flow direction. Pre-install a fluororubber sealing gasket (hardness Shore A70±5) in the notch. Fasten the connecting pipes with threads to ensure that the contact pressure of the sealing surface is ≥2MPa.

[0059] S2, assembling the temperature sensor, the first pressure sensor, the mounting base, the second pressure sensor, and the flow sensor in sequence;

[0060] Assemble the measuring device according to the following steps: air compressor → filter → pressure reducing valve (output pressure adjustment range 0.1-1.0MPa, accuracy 0.5 level) → temperature sensor (PT100, accuracy ±0.5°C) → first pressure sensor (piezoresistive, range 0-1.5MPa, accuracy 0.2 level) → mounting base → second pressure sensor → thermal gas flow sensor (range 0-200L / min, accuracy ±1%FS);

[0061] It should be noted that to avoid turbulent interference, it is necessary to ensure that the length of the straight pipe section upstream of the mounting base is ≥10D (D=10mm), the length of the straight pipe section downstream is ≥5D, and the pipe bending radius is >3D.

[0062] S3. Adjust the gas source module to the target gas supply pressure and stabilize the pressure fluctuation;

[0063] Start the air compressor, adjust the pressure reducing valve to the target air supply pressure P1 (e.g. 0.5 MPa), and maintain the pressure fluctuation <±0.5% through the PID controller;

[0064] S4. The data acquisition module collects the gas temperature, the pressure before and after the nozzle baffle to be tested, and the flow rate in real time, and calculates the flow coefficient Cd according to the throttling formula.

[0065] The data acquisition module collects the gas temperature T (K) through the temperature sensor, collects the pressure p1 at the front end of the nozzle baffle to be tested through the first pressure sensor, collects the pressure p2 at the rear end of the nozzle baffle to be tested through the second pressure sensor, and calculates the pressure difference ΔP before and after the nozzle baffle to be tested = (P1-P2); where P2 is close to atmospheric pressure (101.325kPa); and collects the air pressure volume flow Q (m 3 / s).

[0066] Calculate the instantaneous flow coefficient based on the ISO5167 standard throttling formula:

[0067]

[0068] Where:

[0069] A is the effective flow area of ​​the nozzle baffle to be tested (m 2 ), calculated from the aperture d (A=πd 2 / 4);

[0070] ρ is the gas density (kg / m 3 ), corrected according to the ideal gas state equation:

[0071]

[0072] Where: M is the molar mass of the gas, and R is the universal gas constant.

[0073] In other specific embodiments, the measuring device in this embodiment can be extended to connect to a constant temperature test box for adjusting the test environment temperature within the range of -20°C to 80°C.

[0074] In order to further optimize the above technical solution, the flow coefficient of multiple working conditions can be measured:

[0075] Change the aperture of the nozzle baffle to be tested (0.5mm, 1.0mm, 1.5mm), repeat steps 1-3; adjust the output pressure of the pre-pressure reducing valve (0.2MPa, 0.5MPa, 0.8MPa), and record the Cd value at each pressure point;

[0076] The temperature of the constant temperature box was controlled (-20℃, 25℃, 60℃) and the effect of temperature on Cd was analyzed.

[0077] Example 3:

[0078] The working conditions of the embodiment of the present invention provide a dynamic flow coefficient calibration of a nozzle baffle:

[0079] Apply a step pressure change at the target gas supply pressure and record the flow coefficient response curve;

[0080] If the response time is greater than 2s or the flow coefficient fluctuation range is greater than 1%, it is determined that the nozzle baffle to be tested has abnormal flow resistance.

[0081] For example, when P1 = 0.5 MPa in steady state, the pressure reducing valve output is suddenly increased to 0.7 MPa, and the Cd variation curve over time is recorded by a high-speed data acquisition card (sampling rate 1 kHz) to verify the dynamic response characteristics of the device;

[0082] The results show that the response time for the system to reach steady state is less than 2s and the Cd fluctuation amplitude is less than 0.5%.

[0083] Example 4:

[0084] The present invention discloses a method for testing the temperature sensitivity of a nozzle baffle, comprising:

[0085] Maintain the gas source pressure at 0.5 MPa, raise the ambient temperature to 80°C, and repeat the test;

[0086] Data comparison: ΔP = 0.4 MPa, Q = 21.5 L / min, and C = 0.651 are measured, indicating that the flow coefficient increases with increasing temperature, verifying the influence of temperature on the performance of the nozzle baffle to be tested.

[0087] Example 5:

[0088] The present invention discloses a static pressure differential test for a nozzle baffle:

[0089] When the end of the pipe is blocked, the flow sensor shows zero; the pressure difference between the first pressure sensor and the second pressure sensor at this time is recorded. This value is the static pressure difference characteristic of the nozzle baffle to be tested.

[0090] Example 6:

[0091] The embodiment of the present invention discloses an application of a nozzle baffle sorting function, batch testing and processing nozzle baffles with an aperture of 1.0mm±0.02mm (sample number N=50), and statistically analyzing the Cd distribution; setting the qualified threshold Cd=0.62±0.03, eliminating out-of-tolerance parts, and achieving a sorting accuracy rate of >99%.

[0092] Experimental data verification

[0093] Table 1 Measured Cd values ​​at different pore sizes (P1 = 0.5 MPa, T = 25°C)

[0094] Aperture d(mm) Theoretical Cd Measured Cd Relative error 0.5 0.65 0.648 -0.31％ 1.0 0.63 0.627 -0.48％ 1.5 0.60 0.594 -1.00％

[0095] Example 7:

[0096] An embodiment of the present invention discloses an application of a nozzle baffle flow coefficient measuring device, which is used on an industrial production line, including: setting a qualified threshold range for the flow coefficient and automatically sorting out nozzle baffles to be tested that exceed the tolerance; writing the mapping relationship between the flow coefficient, the target gas supply pressure, and the gas temperature into a servo valve controller to achieve flow self-calibration.

[0097] Integrating this device into a servo valve production line enables: automatic determination of whether the flow characteristics of the nozzle-flapper assembly match design requirements; generating a calibration curve based on the mapping relationship between flow coefficient, target gas supply pressure, and gas temperature, and writing it into the valve controller's EEPROM; and triggering an early warning when an abnormal decrease in Cd (>5%) occurs in a fault mode (e.g., blockage of the nozzle-flapper under test).

[0098] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0099] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A nozzle baffle flow coefficient measuring device, characterized in that: It includes an air source module (1), a fluid control module, a data acquisition module (9) and a host computer (10); The gas source module (1) is used to provide a stable pressure gas source; the fluid control module comprises a temperature sensor (3), a first pressure sensor (4), a mounting seat (5), a second pressure sensor (6), and a flow sensor (7) connected in sequence through pipelines; the temperature sensor (3) is connected to the gas outlet end of the gas source module through a test tube (2); a nozzle baffle (8) to be tested is detachably connected to the mounting seat (5); The data acquisition module (9) is data-connected to the temperature sensor (3), the first pressure sensor (4), the second pressure sensor (6), and the flow sensor (7); and the host computer (10) is communicatively connected to the data acquisition module (9) for data exchange.

2. A nozzle baffle flow coefficient measuring device according to claim 1, characterized in that: The air source module (1) comprises an air compressor, a filter (11) and a pressure reducing valve (12) connected in sequence through pipelines, and the pressure reducing valve (12) is connected to an end of the test tube (2) away from the temperature sensor (3).

3. The nozzle baffle flow coefficient measuring device according to claim 1, characterized in that: Notches (52) corresponding to the pipe openings on both sides are respectively provided on both sides of the mounting seat (5), and the nozzle baffle (8) to be tested is embedded in the notches (52).

4. The nozzle baffle flow coefficient measuring device according to claim 3, characterized in that: A sealing gasket (51) is embedded between the circumference of the nozzle baffle (8) to be tested and the inner wall of the slot (52).

5. The nozzle baffle flow coefficient measuring device according to claim 1, characterized in that: The flow sensor (7) is a thermal gas mass flow meter with a measuring range of 0-200 L / min, an accuracy of ±1% FS, and a built-in temperature compensation algorithm.

6. The nozzle baffle flow coefficient measuring device according to claim 1, characterized in that: The data acquisition module (9) integrates a Kalman filter algorithm for fusing multi-sensor data and outputting a flow coefficient with a comprehensive error of ≤±0.8%.

7. The nozzle baffle flow coefficient measuring device according to claim 2, characterized in that: The air supply pressure of the air compressor is 0.1-1.0 MPa, and the fluctuation rate is less than ±0.5%.

8. A method for measuring the flow coefficient of a nozzle baffle, characterized in that: The nozzle baffle flow rate is measured using a nozzle baffle flow coefficient measuring device according to any one of claims 1 to 7, comprising the following steps: S1. Close the air source module and embed the nozzle baffle to be tested into the mounting seat; S2, assembling the temperature sensor, the first pressure sensor, the mounting base, the second pressure sensor, and the flow sensor in sequence; S3. Adjust the gas source module to the target gas supply pressure and stabilize the pressure fluctuation; S4. The data acquisition module collects the gas temperature, the gas pressure and flow rate in the pipeline before and after the nozzle baffle to be tested in real time, and calculates the flow coefficient according to the throttling formula.

9. The method for measuring the nozzle baffle flow coefficient according to claim 8, characterized in that: Also includes dynamic calibration: Apply a step pressure change at the target gas supply pressure and record the flow coefficient response curve; If the response time is greater than 2s or the flow coefficient fluctuation range is greater than 1%, it is determined that the nozzle baffle to be tested has abnormal flow resistance.

10. The method for measuring the nozzle baffle flow coefficient according to claim 8, characterized in that: The flow coefficient measuring device is used in industrial production lines, including: setting a qualified threshold range for the flow coefficient and automatically sorting out nozzle baffles that are out of tolerance for testing; and writing the mapping relationship between the flow coefficient, the target gas supply pressure, and the gas temperature into a servo valve controller to achieve flow self-calibration.

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