A method for testing the metering performance of a hydrogen dispenser performance testing device

Abstract

The present application relates to the technical fields of metering performance test, and discloses a kind of metering performance test method of hydrogenation machine performance test device.Utilize the high-pressure gas standard value of electronic balance weighing and the high-pressure gas mass flow indication value of the hydrogenation machine device under test are compared, the indication error and repeatability of the hydrogenation machine device under test are calculated;The pressure difference additional pipe capacity mass component introduced by the pressure change before and after pipeline system test is calculated, and the density difference additional pipe capacity mass component introduced by testing different medium, so as to calculate the mass correction amount of the synthesized pipe capacity introduction;Finally, according to the indication error and repeatability, the mass correction amount of the pipe capacity introduction, the metering performance of the hydrogenation machine device under test is comprehensively judged.The present application can comprehensively judge the metering performance of the hydrogenation machine device under test for the hydrogen filling working condition of multiple parameter nonlinear change, avoid the simple determination of the metering performance of the hydrogenation machine device under test by single parameter, so that the test result is more accurate and reliable.

Description

Technical Field

[0001] This invention relates to the field of metrological performance testing technology, specifically to a metrological performance testing method for a hydrogenation machine performance testing device. Background Technology

[0002] Hydrogen is widely used in industry as a chemical raw material. It has good reducing properties and is pollution-free, so it can be used as a reducing agent. Hydrogen has broad application prospects in the field of hydrogen energy, especially in hydrogen fuel cells and distributed energy systems, where it shows great advantages. High-pressure gaseous hydrogen and liquid hydrogen used in hydrogen fuel cell vehicles are currently the most common and direct applications in the transportation sector.

[0003] Compressed hydrogen refueling machines are specialized equipment that provide hydrogen filling services for hydrogen-powered vehicles, ships, trams, aircraft, engineering vehicles, and power generation units. These machines also include control, metering, and pricing functions. Their performance directly affects the safety, reliability, and economy of hydrogen refueling. Testing of hydrogen refueling machines involves multiple aspects, including refueling performance and metering performance. The hydrogen refueling machine performance testing device (hereinafter referred to as the "hydrogen refueling machine device") is a specialized flow standard device for testing the metering performance of hydrogen refueling machines or high-pressure hydrogen mass flow meters. Its technical indicators relate to the traceability system of hydrogen refueling machines and the fairness of hydrogen trade transactions. It is an important flow standard device used by national legal metrological verification institutions.

[0004] The main technical challenges in metering and testing high-pressure hydrogen in hydrogen refueling units include: hydrogen is the least dense gas and highly flammable; it also has strong permeability under high pressure, requiring the materials of the refueling unit and the mass flow meter to resist its corrosive effects; ensuring the long-term stable metering performance of the flow standard device is a challenge; the high operating pressure of high-pressure hydrogen, coupled with the fact that the pipe diameter of the refueling unit and mass flow meter is typically only a few millimeters, means that the hydrogen flow velocity can reach the speed of sound when flowing through the mass flow meter's measuring tube; ensuring the accuracy and safety of flow measurement under high-pressure hydrogen is another challenge; currently, the mass flow meters used in hydrogen refueling units undergo factory testing using water or lower-pressure air or nitrogen as substitute media; ensuring the metering performance of these substitute media under high-pressure hydrogen is a challenge, as are the high cost of actual high-pressure hydrogen flow testing and the need for stringent safety precautions. Currently, there is no corresponding metrological performance testing method for hydrogen refueling equipment and mass flow meters that uses high-pressure hydrogen as the test medium, nor is there testing capability or flow standard device for testing. This can no longer meet the needs of the development of the hydrogen energy industry. Therefore, the rapid development of the hydrogen energy industry urgently requires research on metrological performance testing methods for hydrogen refueling equipment and flow standard devices for testing.

[0005] Currently, the mass flow meters used in high-pressure hydrogen refueling units are typically tested at the factory using room temperature water as the test medium for measurement performance. After testing, they are directly used for high-pressure hydrogen measurement. This measurement performance test method is a static method. When testing at the required flow point, the mass flow meter is set to display mass flow mode. Liquid water passes through the mass flow meter and is injected into the storage tank. The mass flow rate reading of the liquid water passing through the mass flow meter is collected. The mass value of the storage tank before and after filling is weighed using an electronic balance to obtain the standard value of liquid water injected into the storage tank. This standard value is compared with the mass flow rate reading of liquid water passing through the mass flow meter during the same time period to obtain the measurement performance test result of the mass flow meter. Because the physical properties of room temperature water and high-pressure hydrogen differ significantly, if a mass flow meter is used directly for high-pressure hydrogen measurement after testing room temperature water as the test medium, the influence of density difference and additional tube volume mass component caused by testing different media needs to be considered, and the flow coefficient should be corrected. Alternatively, a high-pressure gas with similar physical properties should be used as the test medium for measurement performance testing. Since the mass flow meter is installed after the hydrogen dispenser, the entire hydrogen dispenser unit also needs to use a high-pressure gas with similar physical properties as the test medium for measurement performance testing.

[0006] Conventional metrological performance testing methods involve calculating the indication error and repeatability of the tested hydrogen refueling unit. The metrological performance of the unit and mass flow meter is directly determined based on the magnitude of these two parameters. However, with the rapid development of the hydrogen energy industry, hydrogen refueling scenarios with nonlinear variations in multiple operating parameters have emerged. During hydrogen refueling, hydrogen pressure may vary from 2 MPa to 70 MPa, hydrogen mass flow rate may fluctuate from 0.1 kg / min to 7.2 kg / min, and hydrogen temperature may vary from -40℃ to 70℃. Under these conditions, the influence of hydrogen properties on the metrological accuracy of the refueling unit and mass flow meter is complex. The existing method based on indication error and repeatability becomes inaccurate in these scenarios. Therefore, a new metrological performance testing method is urgently needed to determine the metrological performance of the tested hydrogen refueling unit and mass flow meter. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide a metrological performance testing method for a hydrogen refueling machine performance testing device. This method fully considers various factors affecting the metrological accuracy of the hydrogen refueling machine and can accurately determine the metrological performance of the tested hydrogen refueling machine under hydrogen refueling scenarios with nonlinear changes in multiple operating parameters. The technical solution is as follows:

[0008] A metrological performance testing method for a hydrogenation machine performance testing device, the testing method comprising the following steps:

[0009] Step 1: Compare the standard value of the high-pressure gas measured by the electronic balance with the indicated mass flow rate of the high-pressure gas passing through the hydrogen refueling machine under test, calculate the indication error and repeatability of the hydrogen refueling machine under test, and determine whether the zeroing process of the hydrogen refueling machine under test is required based on the test results of the indication error and repeatability.

[0010] Step 2: Verify the high-pressure gas mass flow rate readings of the hydrogen refueling unit under test by using the synchronously acquired data and the high-pressure gas mass flow rate readings acquired by the standard meter.

[0011] Step 3: Based on the physical property parameters of hydrogen refueling with nonlinear changes in multiple operating conditions, calculate the additional pipe volume mass component introduced by the pressure difference of the pipeline system of the hydrogen refueling unit under test before and after the test.

[0012] Step 4: Consider the impact of different media on the measurement accuracy of the hydrogenation unit and mass flow meter under test, and calculate the additional tube volume mass component introduced by the density difference of different media.

[0013] Step 5: The mass correction amount introduced by the pipe volume is synthesized by combining the pressure difference introduced by the pressure change before and after the pipeline system test with the additional pipe volume mass component and the density difference introduced by the test of different media.

[0014] Step 6: Based on the indication error and repeatability of the tested hydrogen refueling device, the verification results of the tested hydrogen refueling device and the standard meter, and the mass correction amount introduced by the pipe capacity, comprehensively determine the metrological performance of the tested hydrogen refueling device and determine the accuracy class of the tested hydrogen refueling device.

[0015] The beneficial effects of this invention are:

[0016] This invention proposes a zeroing procedure for the tested hydrogen refueling unit, and clarifies the specific parameters that meet the zeroing qualification requirements of the tested hydrogen refueling unit, making the test results more accurate.

[0017] This invention proposes specific parameters for high and low flow rates and methods for adjusting pressure, which meets the requirement of the metrology law that metrology devices such as hydrogenation machines must undergo multi-flow rate testing.

[0018] This invention takes into account the influence of the pressure difference-added pipe volume mass component introduced by the pressure change before and after the test of the pipeline system of the hydrogenation unit under test, and the density difference-added pipe volume mass component introduced by the test of different media on the test results, so as to make the test results more accurate.

[0019] This invention considers the influence of multiple parameters on the test results, such as the indication error and repeatability of the tested hydrogen refueling device, the verification results of the tested hydrogen refueling device and the standard meter, and the mass correction amount introduced by the pipe capacity. It comprehensively judges the metering performance of the tested hydrogen refueling device under the hydrogen refueling conditions with nonlinear changes in multiple parameters, avoiding the simple judgment of the metering performance of the tested hydrogen refueling device by a single parameter, so that the obtained test results are more accurate and reliable. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the working principle of the metrological performance testing system of the present invention.

[0021] Figure 2 This is a flowchart of the metrological performance testing method of the present invention. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] The metrological performance testing method of the hydrogenation machine performance testing device of the present invention uses high-pressure nitrogen or high-pressure hydrogen as the test medium, and the working principle is as follows: Figure 1 As shown, the metrological performance testing system adopts the start-stop mass method principle, and the standard is an electronic balance. The high-pressure gas source is connected to the hydrogen storage container in sequence through the pressure regulating cabinet, inlet valve, standard gauge, outlet valve, front hydrogen injection gun, hydrogen injection device under test, rear hydrogen injection gun, and valve; the hydrogen storage container is placed on the electronic balance.

[0024] The nominal working pressure of the hydrogen refueling machine is between 35MPa and 70MPa, with a maximum working pressure of 87.5MPa. The pressure of the high-pressure gas in the hydrogen refueling machine performance testing device of this invention is also within this range.

[0025] First, a leak test is conducted to ensure the test system is leak-free. After the leak test is completed, hydrogen is added to the storage container. When the pressure in the storage container reaches the required flow rate, the addition is stopped, and the value displayed on the electronic balance is recorded to obtain the standard value of the high-pressure gas mass flow rate. This standard value of the mass flow rate is compared with the indicated value of the high-pressure gas mass flow rate through the hydrogen refueling unit under test to calculate the measurement error and repeatability of the hydrogen refueling unit under test. The indication error of the hydrogen refueling unit under test is evaluated using a comparative method. Based on the test results of the indication error and repeatability, it is determined whether the zeroing procedure of the hydrogen refueling unit under test is required.

[0026] Secondly, the high-pressure gas mass flow rate reading of the tested hydrogen refueling unit is compared with the high-pressure gas mass flow rate value of the standard meter using synchronous time acquisition. This comparison method verifies the indication error of the tested hydrogen refueling unit. Next, based on the nonlinear changes in the physical properties of hydrogen refueling under multiple operating conditions, the additional pipe volume mass component introduced by the pressure difference before and after the test of the tested hydrogen refueling unit's pipeline system is calculated. Finally, based on the above parameters, including the indication error and repeatability of the tested hydrogen refueling unit, the verification results of the tested hydrogen refueling unit and the standard meter, the additional pipe volume mass component introduced by the pressure difference due to pressure changes in the pipeline system, and the additional pipe volume mass component introduced by the density difference due to testing different media, the metrological performance of the tested hydrogen refueling unit is comprehensively judged.

[0027] The metrological performance testing method and procedure of the hydrogenation machine performance testing device are as follows: Figure 2 As shown, it includes the following steps:

[0028] 1. Leak Detection Procedure for Metrological Performance Testing System: First, place the hydrogen storage container stably on the electronic balance. Adjust the high-pressure gas source to the required test pressure range using the pressure regulating cabinet. Open the inlet valve at the front end and the outlet valve at the rear end of the standard gauge, and close the valve at the front end of the hydrogen storage container. The high-pressure gas passes through the standard gauge and the hydrogen refueling device under test to reach the valve at the front end of the hydrogen storage container. After the high-pressure gas fills the pipeline system, maintain the test pressure at the standard gauge for 10 minutes. Check the pressure value displayed on the pressure gauge. The pressure change should not exceed 0.1 MPa. Use leak detection fluid or a gas leak detector to check the pipeline system and the connections of each component. If there is no leakage, the sealing test can be considered qualified. The high-pressure gas is basically in a stable and static state, and the temperature change of the high-pressure gas has a relatively small impact on the pressure fluctuation. Subsequent tests and data acquisition can then be carried out.

[0029] 2. Testing and Data Acquisition Procedure: After the metering performance testing system has completed leak detection, when the pressure, temperature, and other physical properties of the high-pressure gas meet the measurement conditions, return the electronic balance or standard gauge and the hydrogen refueling device under test to zero or record the initial values. Open the valve at the front end of the hydrogen storage container to begin filling it with gas, observing the flow rate displayed on the standard gauge and the pressure value displayed on the pressure gauge during this process. When the pressure in the hydrogen storage container reaches the termination pressure required by the flow range or the mass of the filled high-pressure gas reaches the required flow rate value of the flow range, stop filling and close the valve of the hydrogen storage container. Then disconnect the hydrogen refueling gun at the front end of the hydrogen storage container, record the value displayed on the electronic balance, and obtain the standard value of the high-pressure gas mass flow rate. Compare this standard value with the high-pressure gas mass flow rate indicated by the hydrogen refueling device under test to calculate the measurement error and repeatability of the hydrogen refueling device under test. The comparison method is used to evaluate the indication error of the hydrogen refueling device under test.

[0030] In addition, the high-pressure gas mass flow rate readings of the tested hydrogen refueling unit, collected synchronously, are compared with the high-pressure gas mass flow rate values ​​of the standard meter. This comparison method is used to verify the indication error of the tested hydrogen refueling unit. At least six data points are collected within a flow range. Each data point includes at least the standard value of the high-pressure gas mass flow rate, the mass flow rate readings of the tested hydrogen refueling unit and the standard meter, filling time, pressure and flow rate curves of the high-pressure gas, maximum instantaneous mass flow rate, minimum instantaneous mass flow rate, temperature, density, and other parameters.

[0031] 3. Steps for recording and setting the test flow rate zone: Record the maximum instantaneous mass flow rate of the high-pressure gas displayed on the standard table. If the maximum instantaneous mass flow rate of the high-pressure gas is greater than or equal to 5% and less than 25% of the maximum flow rate range of the hydrogen dispenser, then it is the test low flow rate zone; if the maximum instantaneous mass flow rate of the high-pressure gas is greater than or equal to 25% and less than the maximum flow rate range of the hydrogen dispenser, then it is the test high flow rate zone; control the pressure value of the high-pressure gas source or the pressure value of the hydrogen storage container by adjusting the pressure regulating cabinet to switch from the test high flow rate zone to the test low flow rate zone, or vice versa.

[0032] At this point, the test traffic zone to which the collected data belongs should be recorded. Specific standards for the test traffic zone, test traffic range, and maximum permissible error are shown in Table 1. This refers to the instantaneous mass flow rate in the actual test.

[0033] Table 1 Test Flow Area, Test Flow Range, and Maximum Permissible Error

[0034] .

[0035] 4. Steps for exhaust, retesting, and data acquisition:

[0036] According to the test requirements, the pressure value of the high-pressure gas source or the pressure value of the hydrogen storage container can be controlled by adjusting the pressure regulating cabinet to move from the high flow rate test area to the low flow rate test area, or from the low flow rate test area to the high flow rate test area, and then the direction can be reversed and data collected again.

[0037] During venting, retesting, and data acquisition, the specific conditions of the high-pressure gas storage volume and pressure value within the hydrogen storage container determine whether it is necessary to first vent the high-pressure gas before proceeding with the testing and data acquisition process. If the high-pressure gas storage volume exceeds 90% of the maximum storage volume or the high-pressure gas pressure exceeds 90% of the nominal working pressure, the high-pressure gas must be vented first, and the above testing and data acquisition steps must be repeated according to the required number of tests for each flow rate zone.

[0038] 5. Steps for zeroing the hydrogen refueling unit under test:

[0039] If, after collecting data at least six times within a test flow range, the calculated measurement error and repeatability of the hydrogen refueling unit under test do not meet the requirements but are within a certain range, and the repeatability meets the requirements, the zeroing procedure for the hydrogen refueling unit under test can be performed. First, place the hydrogen storage container stably on an electronic balance. Adjust the high-pressure gas source to the required test pressure range using a pressure regulating cabinet. Open the inlet valve at the front end and the outlet valve at the back end of the standard gauge, and close the valve at the front end of the hydrogen storage container. The high-pressure gas passes through the standard gauge and the hydrogen refueling unit under test to the valve at the front end of the hydrogen storage container. After the high-pressure gas fills the pipeline system, maintain the pressure at the test pressure of the hydrogen refueling unit for 10 minutes. Check the pressure value displayed on the pressure gauge. The pressure change should not exceed 0.1 MPa. Use a leak detector or gas leak detector to check the pipeline system and the connections of each component. If no leaks are found, the sealing performance can be determined to be qualified. The high-pressure gas is basically in a stable and static state. Since the gas temperature change has a relatively small impact on pressure fluctuations, the zeroing procedure for the hydrogen refueling unit under test can be performed. At this point, close the outlet valve at the back end of the standard meter, and complete the zeroing process at least three times according to the zeroing steps specified for the mass flow meter used in the hydrogen refueling unit under test. When the zero point change of the mass flow meter does not exceed the change range specified in the product manual, the zeroing process of the hydrogen refueling unit under test is completed, and the above venting, testing and data acquisition process is repeated.

[0040] 6. Steps for calculating the additional pipe volume mass component introduced by the pressure change in the piping system of the tested hydrogenation unit before and after the test:

[0041] First, calculate the internal volume of the test pipeline system of the hydrogen refueling unit under test. Second, based on the data acquisition results, obtain the pressure change before and after the pipeline system test, the density of the high-pressure gas, and the minimum mass of the high-pressure gas charged into the hydrogen storage container during the test. Then, calculate the additional pipe volume mass component caused by the pressure difference introduced by the pressure change before and after the test of the hydrogen refueling unit's pipeline system.

[0042] ;

[0043] In the formula, The maximum pressure change in the downstream piping system of the tested hydrogen refueling unit before and after the test, in MPa; The internal volume (including quick-connect fittings and high-pressure hoses) of the test piping system at the back end of the hydrogen refueling unit under inspection, in meters. 3 ; For refueling scenarios with nonlinear variations in multiple operating parameters, the density of high-pressure gas (kg / m³) 3 Generally, 1.29 kg / m³ is taken as the standard value. 3 . The minimum mass of high-pressure gas, expressed in kg, is the amount of gas that is introduced into the hydrogen storage container during the test.

[0044] 7. Steps for calculating the additional tube volume mass component of the density difference introduced by different media in the tested hydrogenation unit:

[0045] The hydrogen refueling unit under test is susceptible to measurement errors when tested with different media, such as hydrogen, high-pressure nitrogen, or high-pressure air. Based on test data of the unit's metrological performance under these two different media, the maximum measurement error introduced by testing with different media is determined to be... Its distribution can be considered as a uniform distribution, and the corresponding distribution coefficient is taken. The additional tube volume mass component introduced by the density difference of different media in the tested hydrogenation unit is:

[0046] ;

[0047] In the formula, The maximum measurement error introduced by testing different media in the hydrogen refueling unit under test.

[0048] 8. Steps for comprehensively evaluating the impact of the two additional pipe volume mass components of the tested hydrogenation unit on metering performance:

[0049] Referring to the calculation formula for the total mass correction of each component, calculate the mass correction introduced by the two additional pipe volume mass components of the tested hydrogenation unit:

[0050] ;

[0051] In the formula, Mass corrections are introduced for the two additional tube volume mass components; The pressure difference introduced by the pressure change before and after the test of the pipeline system of the hydrogen refueling unit under inspection is an additional pipe volume mass component. To test the density difference introduced by different media in the hydrogenation unit under test, an additional tube volume mass component is required. and A sensitivity coefficient for adding a tube volume mass component to correspond to the density difference.

[0052] 9. Steps for determining the metering performance of the tested hydrogenation unit:

[0053] Based on parameters such as the indication error and repeatability of the tested hydrogen refueling unit, the verification results of the tested hydrogen refueling unit and the standard gauge, the additional pipe volume mass component caused by pressure difference due to changes in pipeline system pressure, and the additional pipe volume mass component caused by density difference due to testing different media, the metrological performance of the tested hydrogen refueling unit is comprehensively determined, and the accuracy level of a qualified hydrogen refueling unit is determined.

[0054] In the testing and data acquisition process, the start-stop method is used for data acquisition. The electronic balance or standard gauge and the hydrogen refueling unit under test are both zeroed or their initial values ​​are recorded. The valve at the front end of the hydrogen storage container is opened to begin filling the container with gas. During this process, the flow rate reading on the standard gauge and the pressure reading on the pressure gauge are observed. When the pressure in the hydrogen storage container reaches the required termination pressure of the flow range or the mass of the high-pressure gas reaches the required flow rate value of the flow range, gas filling is stopped, the valve of the hydrogen storage container is closed, and then the connection of the hydrogen refueling gun at the front end of the hydrogen storage container is disconnected. The above method can only collect one set of data per gas filling operation. Each set of data must include at least the standard value of the high-pressure gas mass flow rate, the mass flow rate reading of the hydrogen refueling unit under test and the mass flow rate reading of the standard gauge, the filling time, the pressure and flow rate curve of the high-pressure gas, the maximum instantaneous mass flow rate, the minimum instantaneous mass flow rate, temperature, density, and other parameters. Collecting multiple sets of data requires multiple testing and data acquisition steps.

[0055] After data acquisition, the standard value of high-pressure gas mass flow rate is compared with the indicated value of high-pressure gas mass flow rate through the tested hydrogen refueling unit to calculate the measurement error and repeatability of the tested unit. This comparison method is used to evaluate the indication error of the tested hydrogen refueling unit. Furthermore, the high-pressure gas mass flow rate values ​​of the tested unit and the standard meter, acquired synchronously, are compared to verify the indication error of the tested hydrogen refueling unit, including:

[0056] The indicated error of the tested hydrogen refueling unit was calculated based on each set of collected data. Steps:

[0057] ;

[0058] In the formula, To use an electronic balance according to the first The indicated error of the tested hydrogenation unit obtained from the set of data; For the first The high-pressure gas mass flow rate of the tested hydrogen refueling unit collected in the data set; For the first The standard value of high-pressure gas mass flow rate collected by electronic balance in the data set.

[0059] The steps to determine the indicated error of the tested hydrogen refueling unit are as follows: Take the indicated error value in the high flow rate range of the test. The maximum absolute value is used as the indication error in the high flow rate region of the test. The indicated error was taken from the low flow rate region of the test. The maximum absolute value is used as the flow indication error in the low flow range of the test. ;Pick and The maximum value of the two values ​​is taken as the indication error of the hydrogen refueling unit under test. .

[0060] The steps for calculating the measurement repeatability of the tested hydrogenation unit based on the collected data are as follows:

[0061] ;

[0062] In the formula, for l Measurement repeatability in the flow range; In order to be in l The indication error of the tested hydrogenation unit obtained using an electronic balance in the flow range; In order to be in l The average value of the indication error of the tested hydrogenation unit obtained using an electronic balance in the flow range; nl In order to be in l The number of tests required for the traffic zone.

[0063] Steps to determine the measurement repeatability of the tested hydrogenation unit: Measurement repeatability in the high flow rate range is... The measurement repeatability in the low flow rate region is .

[0064] The measurement repeatability in the high flow rate region is:

[0065] ;

[0066] In the formula, To ensure measurement repeatability in the high flow rate region, The single reading error of the tested hydrogenation unit obtained using an electronic balance in the high flow rate region; This represents the average value of the indication error of the tested hydrogenation equipment obtained using an electronic balance in the high flow rate region. ng This refers to the number of tests required in the high-traffic area.

[0067] The measurement repeatability in the low flow rate region is:

[0068] ;

[0069] In the formula, To improve measurement repeatability in the low flow rate region, The error of a single reading of the tested hydrogenation unit obtained using an electronic balance in the low flow rate region; This represents the average value of the indication error of the tested hydrogenation unit obtained using an electronic balance in the low flow rate region. nd This refers to the number of tests required in the low-traffic area.

[0070] Pick and The maximum value of both is used as the measurement repeatability of the tested hydrogenation unit. .

[0071] The indicated error of the tested hydrogen refueling unit was determined based on each set of collected data. The verification steps are as follows:

[0072] ;

[0073] In the formula, To use the standard table according to the first The indicated error of the tested hydrogenation unit obtained from the set of data; For the first The high-pressure gas mass flow rate of the tested hydrogen refueling unit collected in the data set; For the first Mass flow rate readings collected from the standard table in the dataset.

[0074] Take the indicated error in the high flow rate range of the test The maximum absolute value is used as the indication error in the high flow rate region of the test. The indicated error was taken from the low flow rate region of the test. The maximum absolute value is used as the flow indication error in the low flow range of the test. ;Pick and The maximum value of the two values ​​is taken as the indication error of the hydrogen refueling unit under test. .

[0075] Compare and The maximum value of the two values ​​is taken as the indication error of the tested hydrogenation unit. .

[0076] ;

[0077] In the formula, It is the absolute value of the difference between the indication error of the tested hydrogen refueling machine obtained using an electronic balance and the indication error of the tested hydrogen refueling machine obtained using a standard table; The indication error of the tested hydrogenation machine device obtained using an electronic balance; The error of the indicated value of the tested hydrogenation unit is obtained using a standard table.

[0078] The steps for determining whether the metering performance of the tested hydrogen refueling unit is qualified, and the accuracy class of a qualified hydrogen refueling unit:

[0079] when and and and The metering performance of the tested hydrogen refueling unit was deemed qualified and the accuracy class of the tested hydrogen refueling unit was determined to be 0.2.

[0080] when and and and The inspected hydrogen refueling unit was deemed to have qualified metrological performance and an accuracy class of 0.3.

[0081] when and and and The inspected hydrogen refueling unit was deemed to have qualified metrological performance and an accuracy class of 0.5.

[0082] when and and and The metering performance of the tested hydrogen refueling unit was deemed qualified, and the accuracy class of the tested hydrogen refueling unit was determined to be 1.0.

[0083] The accuracy class determination criteria for hydrogenation equipment are shown in Table 2 below.

[0084] Table 2 Accuracy Class Determination Criteria for Hydrogenation Units

[0085] .

[0086] 10. The hydrogen dispensing unit is a dedicated flow standard device for testing the metrological performance of hydrogen dispensing units or high-pressure hydrogen mass flow meters. By assessing the metrological performance of the hydrogen dispensing unit under test, its accuracy class is determined. The hydrogen dispensing unit under test with this accuracy class can be used as a metrological standard device to test hydrogen dispensing units or high-pressure hydrogen mass flow meters of the corresponding accuracy class. The accuracy class of the hydrogen dispensing unit should be less than or equal to half the accuracy class or the absolute value of the maximum permissible error of the hydrogen dispensing unit or high-pressure hydrogen mass flow meter being calibrated. Specific parameters regarding the accuracy class or maximum permissible error of the hydrogen dispensing units or high-pressure hydrogen mass flow meters that can be tested using the hydrogen dispensing unit are shown in Table 3.

[0087] Table 3. Specific parameters for the accuracy class or maximum permissible error of mass flow meters for hydrogen dispensers or high-pressure hydrogen.

[0088] .

[0089] Other requirements for the test include:

[0090] 1. Test medium;

[0091] 1) Use high-pressure gases such as high-pressure air, high-pressure nitrogen, and high-pressure hydrogen as the medium to test the hydrogen refueling device. The pressure value of the high-pressure gas is ≥1.0MPa, and its composition, water dew point, and solid particulate matter should not have a significant impact on the test results.

[0092] 2) When testing the hydrogen refueling unit, during a single measurement, the temperature change of the high-pressure gas source shall not exceed 5°C, and the pressure fluctuation of the high-pressure gas source shall not exceed 0.5 MPa.

[0093] 2. Environmental conditions;

[0094] 1) Ambient temperature: (-10~45)℃. During the test, the ambient temperature change should not exceed 5℃.

[0095] 2) Relative humidity: 35%~95%. During the test, the relative humidity change should not exceed 20%.

[0096] 3) Other influencing factors: Other influencing factors such as power supply, vibration, water vapor condensation in the atmosphere, airflow and magnetic field should not have a significant impact on the test results.

[0097] 3. Measurement performance requirements;

[0098] 1) Maximum permissible error:

[0099] Table 4 shows the accuracy class and corresponding maximum permissible error of mass flow meters for hydrogen refueling equipment or high-pressure hydrogen.

[0100] Table 4. Accuracy Classes and Corresponding Maximum Permissible Errors of Mass Flow Meters for Hydrogen Addition Units or High-Pressure Hydrogen Gas

[0101] .

[0102] 2) Repeatability:

[0103] The repeatability of a hydrogen refueling unit or a mass flow meter for high-pressure hydrogen must not exceed 1 / 2 of the absolute value of the maximum permissible error specified for the corresponding accuracy class.

[0104] 4. Measurement performance testing system;

[0105] Table 5 Technical Specifications of Main Equipment

[0106] .

[0107] The metrological performance testing system used in the test consists of an electronic balance, a standard gauge, a gas source system, a measurement and control system, and test pipelines. The technical specifications of the main equipment are shown in Table 5.

Claims

1. A method of testing the metering performance of a hydrogen dispenser performance testing device, characterized by, The test method comprises the following steps: Step 1: comparing the high-pressure gas standard value weighed by the electronic balance with the high-pressure gas mass flow value displayed by the hydrogen filling device under test, calculating the indication error and repeatability of the hydrogen filling device under test, and judging whether the zero adjustment process of the hydrogen filling device under test is needed according to the test results of the indication error and repeatability; Step 2: verifying the high-pressure gas mass flow value displayed by the hydrogen filling device under test and the high-pressure gas mass flow value displayed by the standard meter synchronously collected with each other; Step 3: according to the physical property parameters of hydrogen gas filling under the nonlinear variation of multi-working condition parameters, calculating the pressure difference additional pipe volume mass component introduced by the pressure change before and after the pipeline system test of the hydrogen filling device under test; Step 4: considering the influence of the hydrogen filling device under test and the mass flow meter on the measurement accuracy under different media, calculating the density difference additional pipe volume mass component introduced by the test of different media; Step 5: synthesizing the mass correction quantity introduced by the pipe volume according to the pressure difference additional pipe volume mass component introduced by the pressure change before and after the pipeline system test and the density difference additional pipe volume mass component introduced by the test of different media; Step 6: comprehensively judging the measurement performance of the hydrogen filling device under test according to the indication error and repeatability of the hydrogen filling device under test, the verification results of the hydrogen filling device under test and the standard meter, and the mass correction quantity introduced by the pipe volume, and determining the accuracy grade of the hydrogen filling device under test; The step 3 specifically comprises: Step 3.1: calculating the internal volume size of the test pipeline system of the hydrogen filling device under test; Step 3.2: According to the data acquisition results, the pressure change amount before and after the pipeline system test, the density of high-pressure gas, and the minimum mass value of high-pressure gas filled into the hydrogen storage container during the test are obtained, and the density difference additional pipe capacity component introduced by the pressure change before and after the pipeline system test of the tested hydrogenation machine device is calculated : ； In the formula, is the maximum value of the pressure change of the back-end pipeline system of the hydrogen filling device under test before and after testing; is the internal volume size of the back-end pipeline system of the hydrogen filling device under test; is the density of high-pressure gas in the refueling scene with nonlinear changes of multi-working condition parameters; is the minimum mass value of high-pressure gas filled in the hydrogen storage container in the test; The step 4 specifically comprises: According to the test data of the metering performance of the tested hydrogenation device under two different media, the maximum measurement error introduced by the tested hydrogenation device in testing different media is The error distribution is uniform distribution, and the corresponding distribution coefficient is taken The density difference additional pipe capacity component introduced by the tested hydrogenation device in testing different media is ； In the formula, is the maximum measurement error introduced by the test of the hydrogenation machine device for different media; The step 5 specifically comprises: comprehensively evaluating the influence of the two additional pipe volume mass components of the hydrogen filling device under test on the measurement performance, and calculating the mass correction quantity introduced by the pipe volume of the two additional pipe volume mass components of the hydrogen filling device under test: ； wherein, is the mass correction introduced for the two additional tank mass components; and is the sensitivity coefficient for the corresponding density difference additional tank mass component; E is the indication error of the hydrogenation device, is the mass value corresponding to each additional tank, is the mass correction introduced for each additional tank; is the indication error of the hydrogenation device being tested.

2. The metrological performance testing method for a hydrogenation machine performance testing device according to claim 1, characterized in that, The measurement performance test system used in the test method comprises: a high-pressure gas source, a pressure regulating cabinet, an inlet valve, a standard meter, an outlet valve, a front hydrogen filling gun, a hydrogen filling device under test, a rear hydrogen filling gun, a valve and a hydrogen storage container connected in sequence through a pipeline system; and the hydrogen storage container is placed on an electronic balance.

3. The method of claim 2, wherein the method further comprises: Before the step 1, the measurement performance test system leak detection step is further included: Firstly, the hydrogen storage container is stably placed on the electronic balance, the high-pressure gas source is adjusted to the pressure range required for the test through the pressure regulating cabinet, the inlet valve at the front end of the standard meter and the outlet valve at the rear end are opened, the valve at the front end of the hydrogen storage container is closed, and the high-pressure gas passes through the standard meter and the hydrogen filling device under test to reach the valve at the front end of the hydrogen storage container; after the pipeline system is filled with the high-pressure gas, the standard meter is kept at the set time under the test pressure, the pressure value displayed by the pressure instrument is checked, and the change amount of the pressure value is less than the set pressure threshold value; the pipeline system and the connection parts of each component are checked by using a leak detection liquid or a gas leak detector, and if there is no leakage, it is determined that the sealing test is qualified.

4. The method of claim 3, wherein the method is a method of testing the metering performance of a hydrogen dispenser, and The step 1 specifically comprises: After the leakage test of the metrological performance test system is completed, when the pressure and temperature of the high-pressure gas meet the measurement conditions, the electronic balance or the standard meter and the indication of the hydrogen filling device under test are all returned to zero or the initial value is recorded; the valve at the front end of the hydrogen storage container is opened to start filling the hydrogen storage container; when the pressure of the hydrogen storage container reaches the required final pressure of the test flow rate range or the mass of the high-pressure gas reaches the required flow rate value of the test flow rate range, the filling is stopped and the valve in front of the hydrogen storage container is closed; Then the connection of the post-hydrogen filling gun is disconnected, the value displayed by the electronic balance is recorded, the standard value of the mass flow rate of the high-pressure gas is obtained, and the standard value of the mass flow rate is compared with the indication of the mass flow rate of the high-pressure gas through the hydrogen filling device under test, so as to calculate the indication error and repeatability of the hydrogen filling device under test; When the hydrogen filling device under test collects a set number of data in a test flow rate range, the calculated measurement error exceeds the required value, the exceeding part is less than the set range, and the repeatability meets the requirements, the zero adjustment process of the hydrogen filling device under test is performed; After the leakage test of the metrological performance test system is completed, the zero adjustment process of the hydrogen filling device under test is performed: the outlet valve at the rear end of the standard meter is closed, and the zero adjustment steps specified by the mass flow meter used by the hydrogen filling device under test are performed at least three times; when the zero point of the mass flow meter changes by not more than the change range specified in the product manual, the zero adjustment process of the hydrogen filling device under test is completed, the exhaust and retest are performed again, and the data collection process is performed.

5. The method of claim 4, wherein the method further comprises: The test flow rate range is set as follows: The maximum instantaneous mass flow rate of the high-pressure gas is recorded, and the maximum instantaneous mass flow rate of the high-pressure gas is greater than or equal to 5% and less than 25% of the maximum value of the flow rate range of the hydrogen filling device, which is the test low flow rate range; the maximum instantaneous mass flow rate of the high-pressure gas is greater than or equal to 25% and less than the maximum value of the flow rate range of the hydrogen filling device, which is the test high flow rate range; the pressure value of the high-pressure source or the pressure value of the hydrogen storage container is adjusted by adjusting the pressure regulating cabinet, so that it is switched from the test high flow rate range to the test low flow rate range, or from the test low flow rate range to the test high flow rate range.

6. The method of claim 5, wherein the method further comprises: Step 2 specifically includes: Step 2.1: Calculate the indication error of the tested hydrogenation device according to each group of data collected by the electronic balance : ； In the formula, The value error of the tested hydrogenation device obtained by the first group data; The value error of the tested hydrogenation device obtained by the second group data; The high-pressure gas mass flow value of the tested hydrogenation device collected in the first group data; The high-pressure gas mass flow standard value collected by the electronic balance in the second Step 2.2: Determine the indication error of the hydrogenation device under test using the electronic balance : The maximum value of the absolute value of the indication error in the test high flow rate region is taken as the indication error of the test high flow rate region The maximum value of the absolute value of the indication error in the test low flow rate region is taken as the flow rate indication error of the test low flow rate region The maximum value of the absolute value of the indication error in the test low flow rate region is taken as the flow rate indication error of the test low flow rate region The maximum value of the absolute value of the indication error in the test low flow rate region is taken as the flow rate indication error of the test low flow rate region The maximum value of the absolute value of the indication error in the test low flow rate region is taken as the flow rate indication error of the test low flow rate region The maximum value of the absolute value of the indication error in the test low flow rate region is taken as the flow rate indication error of the test low flow rate region Step 2.3: Calculate the measurement repeatability of the tested hydrogenation machine device from the data acquired by the electronic balance : ； wherein is l the measurement repeatability of the flow area; is the indication error of the tested hydrogenation machine device obtained by using the electronic balance in the flow area; l is the indication error of the tested hydrogenation machine device obtained by using the electronic balance in the flow area; is the average value of the indication error of the tested hydrogenation machine device obtained by using the electronic balance in the flow area; l is the average value of the indication error of the tested hydrogenation machine device obtained by using the electronic balance in the flow area; nl is the average value of the indication error of the tested hydrogenation machine device obtained by using the electronic balance in the flow area; l is the number of tests required for the flow area; The measurement repeatability of the high flow rate range is: ； wherein is the measurement repeatability in the high flow rate region, is the single value error of the tested hydrogen dispenser device obtained using an electronic balance in the high flow rate region; is the average value of the value error of the tested hydrogen dispenser device obtained using an electronic balance in the high flow rate region; ng is the number of tests required in the high flow rate region; The measurement repeatability of the low flow rate range is: ； wherein M is the measurement repeatability in the low flow rate region, E is the single value error of the tested hydrogen dispenser device obtained using an electronic balance in the low flow rate region; E is the single value error of the tested hydrogen dispenser device obtained using an electronic balance in the low flow rate region; nd N is the number of tests required in the low flow rate region; Take and Both maximum values as the measurement repeatability of the tested hydrogenation device ; Step 2.4: The test hydrogenation device value error is obtained according to each group of data collected from the standard table Verification: ； In the formula, the standard table according to the first group data to obtain the indication error of the tested hydrogenation device; the standard table according to the first group data to obtain the indication error of the tested hydrogenation device; Step 2.5: Determine the indication error of the tested hydrogenation device using the standard table : The maximum value of the absolute value of the indication error in the test high flow rate region is taken as the indication error of the test high flow rate region The maximum value of the absolute value of the indication error in the test low flow rate region is taken as the flow rate indication error of the test low flow rate region The maximum value of the absolute value of the indication error in the test low flow rate region is taken as the flow rate indication error of the test low flow rate region The maximum value of the absolute value of the indication error in the test low flow rate region is taken as the flow rate indication error of the test low flow rate region The maximum value of the absolute value of the indication error in the test low flow rate region is taken as the flow rate indication error of the test low flow rate region The maximum value of the absolute value of the indication error in the test low flow rate region is taken as the flow rate indication error of the test low flow rate region Step 2.6: Compare the two UEs and Take the maximum of the two as the final UE of the tested hydrogen dispenser ; ； In the formula, The absolute value of the difference between the indication error of the hydrogenation device under test obtained using the electronic balance and the indication error of the hydrogenation device under test obtained using the standard table .

7. The method of claim 6, wherein the method further comprises: Step 6 specifically includes: The steps of determining whether the metrological performance of the hydrogen filling device under test is qualified and the accuracy level of the qualified hydrogen filling device are: When , , and , it is determined that the tested hydrogenation device metering performance is qualified and the tested hydrogenation device accuracy level is 0.2 level. When , , and , it is determined that the tested hydrogenation device is qualified in terms of metering performance and the accuracy level of the tested hydrogenation device is 0.

3. When , , and , it is determined that the tested hydrogenation device is qualified in terms of metering performance and the accuracy level of the tested hydrogenation device is 0.

5. When , , and , it is determined that the tested hydrogenation device is qualified in terms of metering performance and the accuracy level of the tested hydrogenation device is 1.0.

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