A method for quickly determining the orifice diameter of a customized throttle plate and a throttle plate

Abstract

The application discloses a kind of custom throttle orifice quick determination method for throttle plate, according to the field pipe diameter d0, design pressure P0 requirement, determine the upper limit d of custom throttle orifice for throttle plate up And lower limit d down Between upper limit d up And lower limit d down Design several test throttle plates of different throttle orifice, install the several test throttle plates to be measured pipeline one by one to carry out measurement test, test data include throttle orifice d of throttle plate, pressure loss δP, according to test data, obtain the coefficient value of polynomial by polynomial fitting, then according to the polynomial after fitting and target pressure loss value, obtain the target throttle orifice of throttle plate.Quick determination of custom throttle orifice for throttle plate is realized, the efficiency of aperture determination can be obviously improved, the number and frequency of test throttle plate production can also be essentially reduced, and the loss is reduced.

Description

Technical Field

[0001] This invention belongs to the field of fluid detection technology, specifically relating to a method for rapidly determining the throttling orifice diameter of a customized throttling plate and the throttling plate itself. Background Technology

[0002] A flow meter (or regulating orifice plate or multi-hole plate) is a measuring instrument used to measure fluid flow rate. It is a primary sensing device of a differential pressure flow meter. Its working principle is as follows: when fluid passes through the flow meter installed in the pipeline, a pressure difference is generated before and after the flow meter. The flow rate can be calculated by measuring the magnitude of this pressure difference. A disadvantage is that the fluid experiences a certain pressure loss after passing through the flow meter.

[0003] Because standard flowmeters have strict requirements on the length of the straight pipe sections before and after the orifice plate when used for flow measurement, otherwise the accuracy and stability of the measurement are difficult to guarantee. Therefore, for some special applications, such as reactor cooling water pipelines, certain nodes that must be monitored for flow may not have sufficient straight pipe length. In particular, for non-standard pipe specifications or uneven pipe walls, the measurement accuracy of standard flowmeters will be significantly reduced.

[0004] Therefore, it is necessary to develop customized throttle plates suitable for specific situations, and the key to customized throttle plates lies in determining the throttle orifice diameter. Currently, the main method for determining the throttle orifice diameter of customized throttle plates is the experimental method. Through multiple experiments, a suitable orifice diameter is found before production, and the production volume is generally not large, with a lot of time spent on testing.

[0005] Due to the high precision requirements for throttling orifice design in certain special situations, such as the ±1% accuracy requirement for pressure loss of throttling plates used in nuclear power plant reactor cooling water pipelines (i.e., the pressure loss error cannot exceed ±1% of the design value under a specific flow rate); and the minimum accuracy requirement for flow measurement (i.e., the measurement error cannot exceed ±0.5% within the design flow range), the design precision of the throttling orifice must be accurate to 0.01mm (only this precision can meet the measurement and pressure loss requirements). It generally takes many days, sometimes even more than ten days, of testing to find a suitable orifice parameter. The efficiency of orifice determination is very low, and there is an urgent need for a more efficient orifice determination method. Summary of the Invention

[0006] To address the above problems, this invention presents a method for rapidly determining the throttling orifice diameter of a customized throttling plate. This method involves conducting a series of targeted and continuous experiments, and then using fitting analysis of the experimental data to quickly determine the ideal throttling orifice diameter.

[0007] This invention discloses a method for rapidly determining the orifice diameter of a customized throttling plate. Based on the on-site pipe diameter d0 (also known as pipe specification), design pressure P0, and accuracy and pressure loss requirements, the upper limit d of the orifice diameter of the customized throttling plate (this invention uses diameter measurement) is determined. up and lower limit d down The method further includes the following steps:

[0008] S0. Determine the upper and lower limits of the test throttle plate orifice diameter; this is a default and natural step in determining the throttle plate orifice diameter, and it is reasonable to include it as one of the steps.

[0009] S1. Design and test a throttling plate, at the upper limit d up and lower limit d down Several experimental throttling plates with different orifice diameters are designed within a certain range (including upper and lower limits), and the number of such experimental throttling plates is n. b The number of undetermined coefficients in the polynomial is not less than the number of undetermined coefficients in the polynomial, i.e., n b Test throttling plates with different orifice diameters;

[0010] S2. Test each test throttling plate and record the test data. Install each of the test throttling plates onto the pipeline to be tested and record the test data. The test data includes the throttling orifice diameter d (called the independent variable in the polynomial) and pressure loss (pressure loss, called the dependent variable in the polynomial) δP. During the test, the inlet fluid flow rate Q, pressure P, and flow velocity v of the throttling plate are kept constant, and other test fluid types, temperatures, and other environmental conditions remain unchanged.

[0011] S3. Polynomial fitting: Perform polynomial fitting based on experimental data to obtain the values ​​of each coefficient of the polynomial.

[0012] S4. Calculate the target throttling orifice diameter. Based on the fitted polynomial and the target pressure loss value, the target throttling orifice diameter of the throttling plate can be obtained. If a higher-order polynomial is used, multiple orifice diameter values ​​may be obtained by analytical methods for the target pressure loss value. However, in engineering practice, only one of these multiple values ​​is generally reasonable, which is easy to determine. This is also a mature technology for solving polynomial engineering problems.

[0013] Although polynomial fitting is an existing technology, this invention is the first to apply it to the field of determining the throttling orifice diameter of a customized throttling plate. Through the design and testing of a complete set of experimental throttling plates, the throttling orifice diameter of the customized throttling plate is determined quickly, which can significantly improve the efficiency of orifice diameter determination. Essentially, it can also reduce the number and number of experimental throttling plates to be manufactured, thus reducing losses.

[0014] Furthermore, the incremental value Δd of the test throttling plate orifice diameter is taken as...

[0015] Δd=(d up -d down) / (n b -1).

[0016] Furthermore, the polynomial order is 2, and the number of test throttling plates is n. b ≥6.

[0017] The specific expression is as follows

[0018] δP=ad 2 +bd+c

[0019] Where δP is the pressure loss, d is the aperture, and a, b, and c are undetermined coefficients.

[0020] Furthermore, the polynomial order is 4th or 6th. For a 4th order polynomial, the number of test throttling plates n b ≥10; for a 6th order polynomial n b ≥14.

[0021] Furthermore, the target orifice diameter calculation method includes a numerical calculation method, which includes: based on the target pressure loss value, finding the test throttling plate orifice diameter values ​​corresponding to the upper limit pressure loss value and the lower limit pressure loss value in the test data that are closest to the target pressure loss value, and recording them as the upper limit d1 and the lower limit d2, respectively; setting the numerical calculation orifice diameter step size δd, wherein the step size does not exceed the orifice diameter accuracy index requirement; decreasing the step size step by step from the upper limit d1, or increasing the step size step by step from the lower limit d2; calculating the pressure loss value according to the polynomial model; and the orifice diameter value corresponding to the set of results that is closest to the target pressure loss value is the target orifice diameter value.

[0022] Furthermore, before the polynomial fitting, it is first determined whether there are any abnormal tests. If so, the abnormal test results are removed and supplemented until the test results are normal. The cause of the abnormality may be changes in the environment, such as pressure fluctuations or temperature changes.

[0023] Furthermore, the method for judging abnormal test results includes: arranging the test throttle plate orifice diameters in sequence, any measured pressure loss values ​​that show an overall monotonically increasing or monotonically decreasing relationship are considered normal values; any measured pressure loss value that exceeds the monotonically increasing or monotonically decreasing range is considered an outlier. Exceeding the monotonically increasing or monotonically decreasing range includes the measured value being larger than its adjacent theoretically relatively larger measured value, or smaller than its adjacent theoretically relatively smaller measured value.

[0024] On the other hand, a throttle plate, a test throttle plate or an engineering testing throttle plate made according to the throttle orifice diameter determined by any of the above-mentioned methods for rapidly determining the throttle orifice diameter of a customized throttle plate.

[0025] The advantages and beneficial effects of this invention are as follows: The method and the invention itself for rapidly determining the orifice diameter of a customized throttle plate combine experimentation and data analysis. This overcomes the uncertainty and randomness inherent in obtaining the ideal orifice diameter through simple experiments, and also overcomes the probabilistic nature of orifice diameters obtained through purely theoretical analysis without practical environmental support, where the orifice diameter may not meet usage requirements. This method enables rapid determination of the orifice diameter of a customized throttle plate, significantly improving the efficiency of orifice diameter determination from an average of over 5 days to less than 2 days. Essentially, it also reduces the number and frequency of experimental throttle plate fabrication, thus lowering losses. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the steps of a method for quickly determining the orifice diameter of a customized throttle plate. Detailed Implementation

[0027] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0028] Example 1

[0029] This invention discloses a method for rapidly determining the orifice diameter of a customized throttling plate. Based on the on-site pipe diameter d0 (also known as pipe specification), design pressure P0, and accuracy and pressure loss requirements, the upper limit d of the orifice diameter of the customized throttling plate (this invention uses diameter measurement) is determined. up and lower limit d down (The theoretical value can be calculated based on fluid mechanics theory, and then the error range can be analyzed based on possible error sources to obtain the upper and lower limits of the orifice diameter. A simulation model can be built using fluid network calculation software like Flowmaster to assist in this process. Alternatively, the upper and lower limits can be estimated based on empirical parameters of similar pipe types. In engineering, this is generally estimated based on experience. Current orifice diameter testing methods also involve first estimating a range, conducting tests to confirm it, selecting an intermediate parameter based on the test results, and then conducting tests again, gradually approximating the range. However, due to the high accuracy requirements, the approximation efficiency is low. In this embodiment, because there is a definite β value (orifice diameter to pipe diameter ratio), the upper limit d of the throttling orifice diameter is determined.) up and lower limit d down It is possible to do so; theoretically, the smaller the upper and lower limits, the better. The method also includes the following steps:

[0030] S0. Determine the upper and lower limits of the test throttle plate orifice diameter; this is a default and natural step in determining the throttle plate orifice diameter, and it is reasonable to include it as one of the steps.

[0031] S1. Design and test a throttling plate, at the upper limit dup and lower limit d down Several experimental throttling plates with different orifice diameters are designed within a certain range (including upper and lower limits), and the number of such experimental throttling plates is n. b The number of undetermined coefficients is no less than the number of undetermined coefficients in the polynomial, i b Test throttling plates with different orifice diameters; for example, two undetermined coefficients for a linear polynomial, three undetermined coefficients for a quadratic polynomial, seven undetermined coefficients for a sixth-degree polynomial, and so on. The only difference between test throttling plates in the same group is the orifice diameter; the number, layout, orifice edge shape, plate thickness, and other parameters are all the same. In fact, test throttling plates can sometimes be reused for different pipeline test environments, as long as the upper and lower limit requirements are met. Therefore, sometimes test throttling plates do not need to be remade; it is only necessary to select a suitable one from the existing throttling plates.

[0032] S2. Test each test throttling plate and record the test data. Install each of the test throttling plates onto the pipeline to be tested and record the test data. The test data includes the throttling orifice diameter d (called the independent variable in the polynomial) and pressure loss (pressure loss, called the dependent variable in the polynomial) δP. During the test, the inlet fluid flow rate Q, pressure P, and flow velocity v of the throttling plate are kept constant, and other test fluid types, temperatures, and other environmental conditions remain unchanged.

[0033] S3. Polynomial fitting: Based on the experimental data, polynomial fitting is performed to obtain the coefficient values ​​of the polynomial. In this embodiment, a univariate polynomial is established with aperture as the independent variable and pressure loss as the dependent variable. Several experiments can obtain the same number of sets of experimental data. When the number of sets of experimental data is greater than or equal to the number of undetermined coefficients of the polynomial, the undetermined coefficients can be solved according to the basic principle of polynomial fitting.

[0034] S4. Calculate the target throttling orifice diameter. Based on the fitted polynomial and the target pressure loss value, the target throttling orifice diameter of the throttling plate can be obtained. If a higher-order polynomial is used, multiple orifice diameter values ​​may be obtained by analytical methods for the target pressure loss value. However, in engineering practice, only one of these multiple values ​​is generally reasonable, which is easy to determine. This is also a mature technology for solving polynomial engineering problems.

[0035] This experiment only tests the relationship between the orifice diameter and pressure loss of a throttling plate under specific environmental conditions. Therefore, the test fluid, pipeline, installation location, pressure, flow rate, and other environmental parameters must be fixed. The polynomial is a univariate polynomial, meaning it has only one independent variable. Similarly, if it is necessary to test the combined relationship between pressure loss and orifice diameter, pressure, and flow rate, the polynomial is a ternary polynomial (of course, it is also possible to test only the relationship between two factors and pressure loss, i.e., a bivariate polynomial, which will not be elaborated further). The design method for the test throttling plate is the same as above, and under the premise of fixing the test fluid type, pipeline, and installation location, tests should be conducted with various combinations of orifice diameter, pressure, and flow rate values. To ensure the integrity of the test data, each test generally only changes one independent variable parameter value. That is, for a certain orifice diameter and a certain pressure value, different flow rate values ​​are tested one by one, and then the same orifice diameter and the next pressure value are tested one by one to complete the test for all flow rate values. Ideally, the number of tests should not be less than n. d *n P *n v , where n d n P n v These represent the number of different orifice sizes, the number of different pressure values, and the number of different flow rates tested. Alternatively, a small-sample test method can be used. While it's not required that all combinations of independent variable values ​​be fully covered, at least every value should be covered. However, the accuracy of the resulting fitted model will be worse than that obtained with full combinations and full coverage.

[0036] Although polynomial fitting is an existing technology, this invention is the first to apply it to the field of determining the throttling orifice diameter of a customized throttling plate. Through the design and testing of a complete set of experimental throttling plates, the throttling orifice diameter of the customized throttling plate is determined quickly, which can significantly improve the efficiency of orifice diameter determination. Essentially, it can also reduce the number and number of experimental throttling plates to be manufactured, thus reducing losses.

[0037] Preferably, the increment value Δd of the test throttling plate orifice diameter is taken as:

[0038] Δd=(d up -d down ) / (n b -1).

[0039] That is, the test throttle plate orifice diameter is from d down Start by increasing the increment by Δd until d is reached. upThe orifice diameter values ​​are increased at equal intervals; although this is a relatively ideal test plate design, it is not necessary. What is necessary is that the orifice diameter distribution of the test throttle plate should not be too concentrated in a small range, and it is better to tend to a uniform distribution. In the case where the ideal orifice diameter value is most likely to fall into a smaller region, while the orifice diameter of the test throttle plate is basically uniformly distributed within the upper and lower limits, the distribution is denser in that smaller local region. The test and the final orifice diameter determination results will be closer to the ideal value.

[0040] Preferably, the target orifice diameter calculation method includes a numerical calculation method, which includes: based on the target pressure drop value, finding the test throttling plate orifice diameter values ​​corresponding to the upper limit pressure drop value and the lower limit pressure drop value in the test data that are closest to the target pressure drop value, denoted as upper limit d1 and lower limit d2 respectively; setting a numerical calculation orifice diameter step size δd, wherein the step size does not exceed the orifice diameter accuracy index requirement, decreasing step by step from upper limit d1, or increasing step by step from lower limit d2; calculating the pressure drop value according to a polynomial model; and the orifice diameter value corresponding to the set of results closest to the target pressure drop value is the target orifice diameter value. In this embodiment, the orifice diameter accuracy requirement is 0.01mm, and δd = 0.001mm is taken.

[0041] Preferably, the polynomial order is 2, and the number of test throttling plates is n. b ≥6, this embodiment designs n b =10, mainly to ensure sufficient sampling data.

[0042] The specific expression is as follows

[0043] δP=ad 2 +bd+c

[0044] Where δP is the pressure loss, d is the aperture, and a, b, and c are undetermined coefficients.

[0045] This embodiment designs 10 test throttling plates. Theoretically, the more test throttling plates with different orifice diameters there are, the more reliable the fitting results will be. However, this also leads to an increase in the number of tests and a decrease in efficiency. Therefore, a compromise should be made between the two. Ten tests are already quite a lot for univariate quadratic polynomial sampling. In terms of experimental efficiency, as long as the process is carried out step by step, ten tests are not too many and can be conducted continuously. The test can be completed in a short period of time. The main time should be spent on the design and manufacturing of the test throttling plates. If you are lucky, the orifice diameter of one of the test throttling plates will directly meet the requirements.

[0046] Example 2

[0047] The difference from Example 1 is that the polynomial order is 4th or 6th, and the number of test throttling plates n b≥10. This embodiment designed 20 experimental throttling plates. Although the order is a bit high, there is enough sample data, and within a very small range, it is almost impossible to overfit.

[0048] Example 3

[0049] The difference from Example 1 is that the polynomial order is 6, and the number of test throttle plates n b ≥14. This embodiment designed 20 test throttling plates.

[0050] Analysis of polynomial order selection in Examples 2 and 3: Based on the empirical formula for estimating pressure loss of orifice plate flowmeters

[0051] δP=ΔP*(1-αβ 2 ) / (1+αβ 2 )

[0052] and

[0053] ΔP=0.5ρ(4Q / παd 2 ) 2

[0054] Where δP is the pressure loss, ΔP is the static pressure difference before and after the orifice plate, α is the flow coefficient, β is the orifice-to-pipe diameter ratio, Q is the flow rate, d is the orifice diameter, and ρ is the fluid density.

[0055] Based on the above empirical formulas, classifying a polynomial as either a 4th-order or 6th-order polynomial has theoretical or empirical basis. However, considering that higher-order polynomials are prone to overfitting, and that lower-order polynomials do not produce significant errors over shorter numerical intervals, it is recommended that the order of the polynomial be less than or equal to 6.

[0056] Example 4

[0057] The difference from Example 1 is that before the polynomial fitting, it is first determined whether there are abnormal tests. If there are, the abnormal test results are removed and supplementary tests are conducted until the test results are normal. The abnormality may be due to changes in the environment, such as pressure fluctuations or temperature changes. After removing outliers and supplementing tests, the final aperture determination result can be more reliable.

[0058] Preferably, the method for judging abnormal test results includes: Arranging the test throttling plate orifice diameters in order, any measured pressure loss values ​​showing an overall monotonically increasing or decreasing relationship are considered normal values ​​(in this embodiment, the orifice diameters are arranged from small to large, so the theoretical pressure loss values ​​should decrease, i.e., gradually decrease). Any measured pressure loss value exceeding the monotonically increasing or decreasing range is considered an outlier. Exceeding the monotonically increasing or decreasing range includes the measured value being larger than its adjacent theoretically larger measured value, or smaller than its adjacent theoretically smaller measured value. Using a graph can more intuitively determine outliers, i.e., the measured value is not within the range of the monotonically increasing or decreasing curve, and is larger than its adjacent theoretically larger sampling point or smaller than its adjacent theoretically smaller sampling point.

[0059] Example 5

[0060] A throttling plate, characterized in that it is a test throttling plate or an engineering testing throttling plate manufactured according to the throttling orifice diameter determined by a method for rapidly determining the throttling orifice diameter of a customized throttling plate as described in any one of embodiments 1 to 4 and their preferred embodiments.

[0061] The basic principle of this invention is as follows: Traditional methods for obtaining the orifice diameter of a customized throttle plate either involve physical testing, directly using model simulation results, or confirming the results through physical testing. In contrast, the polynomial fitting method for calculating the orifice diameter in this invention is, in fact, a numerical model method, which can also be considered a simulation method. The difference is that this model is determined through physical testing, and the physical testing is specially designed to make the model more reliable. The target orifice diameter value calculated by this dedicated model is more credible, provided that the preceding experimental environment parameters remain unchanged and the experimental data is reliable. Of course, if obviously abnormal experimental data appears, it can be detected manually, and the data can be discarded or additional tests can be performed. Therefore, the rapid determination method for the throttle orifice diameter of a customized throttle plate proposed in this invention is highly operable and easy to implement, which can greatly shorten the time spent on determining the orifice diameter of a customized throttle plate using traditional methods, while also reducing the number of test throttle plates and lowering experimental losses.

[0062] The above description is only a part of the relatively systematic and comprehensive method for rapidly determining the orifice diameter of a customized throttle plate and an embodiment of the throttle plate according to the present invention. In fact, other non-strictly uniform distribution schemes can also be considered for the design of the orifice diameter of the experimental throttle plate. In addition, if the upper and lower limit ranges are relatively small, a first-order linear polynomial can be selected for the polynomial order, or other orders can be selected. If the influence of pressure or flow rate changes on pressure loss is considered, a bivariate or ternary polynomial can also be established. Furthermore, outlier elimination methods, specific numerical calculation methods, etc., can be further optimized and selected. These combinations or preferred schemes should also be considered within the scope of protection of the present invention, and will not be listed one by one here.

Claims

1. A method for rapidly determining the orifice diameter of a custom-designed throttling plate, wherein the upper limit d of the orifice diameter of the custom-designed throttling plate is determined based on the on-site pipe diameter d0 and the design pressure requirement P0. up and lower limit d down Its characteristics are, The method further includes the following steps: S1. Design and test a throttling plate, at the upper limit d up and lower limit d down Several test throttling plates with different orifice diameters are designed between them, and the number of test throttling plates is n. b No less than the number of undetermined coefficients of the polynomial; S2. Test each test throttling plate and record the test data. Install each of the test throttling plates onto the pipeline to be tested and perform measurement tests. The test data includes the throttling orifice diameter d of the throttling plate and the pressure loss δP. S3. Polynomial fitting: Based on the experimental data, polynomial fitting is performed to obtain the coefficient values ​​of the polynomial; the order of the polynomial is greater than or equal to 2 and less than or equal to 6. S4. Calculate the target throttling orifice diameter. Based on the fitted polynomial and the target pressure loss value, obtain the target throttling orifice diameter of the throttling plate. The target orifice diameter calculation method includes a numerical calculation method, which includes: based on the target pressure loss value, finding the test throttling plate orifice diameter values ​​corresponding to the upper limit pressure loss value and the lower limit pressure loss value in the test data that are closest to the target pressure loss value, and recording them as the upper limit d1 and the lower limit d2, respectively; setting the numerical calculation orifice diameter step size δd, wherein the step size does not exceed the orifice diameter accuracy index requirement; decreasing the step size step by step from the upper limit d1, or increasing the step size step by step from the lower limit d2; calculating the pressure loss value according to the polynomial model; and the orifice diameter value corresponding to the set of results that is closest to the target pressure loss value is the target orifice diameter value.

2. The method for rapidly determining the throttling orifice diameter of a customized throttling plate according to claim 1, characterized in that, The incremental value Δd of the test throttling plate orifice diameter is taken as: Δd=(d up -d down ) / (n b -1)。 3. The method for rapidly determining the throttling orifice diameter of a customized throttling plate according to claim 1, characterized in that, The polynomial order is 2.

4. The method for rapidly determining the throttling orifice diameter of a customized throttling plate according to claim 3, characterized in that, The number of test throttle plates n b ≥6.

5. The method for rapidly determining the orifice diameter of a customized throttling plate according to claim 1, characterized in that, The polynomial order is 4 or 6.

6. The method for rapidly determining the throttling orifice diameter of a customized throttling plate according to claim 5, characterized in that, For a fourth-order polynomial, the number of test throttle plates n b ≥10; for a 6th order polynomial n b ≥14.

7. The method for rapidly determining the throttling orifice diameter of a customized throttling plate according to claim 1, characterized in that, Before the polynomial fitting, it is first determined whether there are abnormal experiments. If so, the abnormal experimental results are removed and supplemented until the experimental results are normal.

8. The method for rapidly determining the throttling orifice diameter of a customized throttling plate according to claim 7, characterized in that, The method for judging abnormal test results includes: arranging the test throttle plate orifice diameters in order, any measured pressure loss values ​​that show an overall monotonically increasing or monotonically decreasing relationship are considered normal values. Any measured pressure loss value that exceeds the monotonically increasing or monotonically decreasing range is considered an outlier. The exceeding of the monotonically increasing or monotonically decreasing range includes the measured value being larger than its adjacent theoretically relatively larger measured value, or smaller than its adjacent theoretically relatively smaller measured value.

Images