Calibration Test Method for K-coefficient of Turbine Flow Meters

Abstract

This invention provides a calibration test method for evaluating the influence of the K-coefficient of a turbine flow meter, comprising the following steps: S1, modifying a standard volumetric tube liquid flow calibration bench; S2, arranging a high-precision pressure measuring point P1 and a first density measuring point M1 in front of the flow meter to be calibrated, and synchronously acquiring signals from the high-precision pressure measuring point, the first density measuring point, the frequency f of the flow meter to be calibrated, the volumetric flow rate of the volumetric tube, and the second density measuring point M2 in real time; S3, obtaining the K-coefficient of the turbine flow meter under different medium pressures according to the calculation formula. This invention, when applied to aero-engine flight tests, will improve the accuracy of fuel flow measurement. The calibration test method supports the verification of the overall engine performance and also supports the evaluation of the economic efficiency of civil aero-engines.

Description

Technical Field

[0001] This invention relates to the field of aero-engine testing, and in particular to a calibration test method for evaluating the influence of the K coefficient of a turbine flow meter. Background Technology

[0002] In existing technologies, turbine flow meters are mostly used to measure fuel flow parameters during aero-engine flight tests. The test conditions for turbine flow meters are quite complex, with medium pressure ranging from atmospheric pressure to 10 MPa. The medium pressure affects the viscosity of the medium and the geometry of the turbine flow meter, which in turn affects the instrument coefficient (K coefficient) of the turbine flow meter. Therefore, the influence of medium pressure on the K coefficient of the turbine flow meter must be considered during actual calibration.

[0003] However, the current domestic standard JJG 1037-2008 "National Metrological Verification Regulation for Turbine Flow Meters" only stipulates that the pressure of the liquid used for verification at any point in the pipeline system and the flow meter must be higher than its saturated vapor pressure, which does not meet the calibration requirements of turbine flow meters under actual test conditions.

[0004] For example, the measurement accuracy of the K coefficient obtained using the current national calibration standards for a certain type of commercial aircraft engine does not meet the accuracy requirements proposed by the airworthiness and aircraft manufacturers.

[0005] In view of this, the inventors of this application have designed a calibration test method for evaluating the influence of the K coefficient of a turbine flow meter, in order to overcome the above-mentioned technical problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology in which turbine flow meter testing cannot meet the calibration requirements under actual test conditions, and to provide a calibration test method for evaluating the influence of the K coefficient of turbine flow meter.

[0007] The present invention solves the above-mentioned technical problems through the following technical solution:

[0008] A calibration test method for evaluating the influence of the K-coefficient of a turbine flow meter, characterized in that the calibration test method is used to evaluate the influence of fuel medium pressure on the K-coefficient of the turbine flow meter, and includes the following steps:

[0009] S1. Modify the standard volumetric tubular liquid flow calibration bench;

[0010] S2. Arrange a high-precision pressure measuring point P1 and a first density measuring point M1 in front of the flow meter to be calibrated, and collect the signals of the high-precision pressure measuring point, the first density measuring point, the frequency f of the flow meter to be calibrated, the volumetric flow rate of the volume tube, and the second density measuring point M2 in real time.

[0011] S3. Obtain the K coefficient of the turbine flow meter under different medium pressures according to the calculation formula:

[0012]

[0013] Where f represents the flow meter output frequency in Hz; m 标 Q represents the standard fuel mass flow rate (kg / min) provided in the calibration test; 标 The standard volumetric flow rate of the volumetric tube during the calibration test is represented by L / min; ρ1 represents the density of the fuel medium at the flow meter (kg / m³). 3 ρ2 represents the density of the fuel medium at the volumetric pipe (kg / m³). 3 .

[0014] According to one embodiment of the present invention, in step S1, a high-pressure pump, a pressure regulating overflow valve, an accumulator and a flow regulating valve are used to stably control the pressure of the fuel medium entering the inlet of the flow meter being measured, while simultaneously meeting the flow requirements of the flow meter being calibrated.

[0015] According to one embodiment of the present invention, in step S1, the pressure control accuracy is ±0.05MPa, the flow rate fluctuation is ±20L / h, and the pressure of the medium flowing through the volume tube is kept at atmospheric pressure through the flow regulating valve and the back pressure regulating device.

[0016] According to one embodiment of the present invention, a standard and a volumetric tube are connected in series after the flow meter being measured, a flow regulating valve and a water-cooled heat exchanger are provided before the volumetric tube, and a back pressure regulating device is provided after the volumetric tube, so that the pressure of the medium flowing through the volumetric tube is at normal temperature and pressure.

[0017] According to one embodiment of the present invention, in step S2, the high-precision pressure measuring point P1 and the first density measuring point M1 are arranged at a position with a length-to-diameter ratio of 10 in front of the flow meter being calibrated.

[0018] According to one embodiment of the present invention, the step S3 is followed by the following step:

[0019] S4. Calculate the standard flow rate value. The calculation formula is:

[0020]

[0021] in, Q represents the standard fuel mass flow rate (kg / h) provided in the calibration test; 标 ρ2 represents the standard volumetric flow rate of the volumetric tube during the calibration test (L / min); ρ2 represents the density reading at the medium density measuring point in the volumetric tube (kg / m2). 3 .

[0022] According to one embodiment of the present invention, the step S4 is followed by the following step:

[0023] S5. Calculate the output frequency of the flow meter being calibrated, f 被校 The calculation formula is:

[0024]

[0025] Among them, f 被校 The frequency signal (Hz) output by the flowmeter being calibrated during the calibration test is represented by Hz; N represents the pulse signal output by the flowmeter being calibrated within time t.

[0026] According to one embodiment of the present invention, the step S5 is followed by the following step:

[0027] S6. The formula for calculating the instrument coefficient K of the flow meter being calibrated is transformed as follows:

[0028]

[0029] Where ρ1 represents the density reading at point M1 of the flowmeter (kg / m³). 3 K represents the instrument coefficient of the flow meter being calibrated.

[0030] According to one embodiment of the present invention, after step S6, the following step is further included:

[0031] S7. Set the fuel flow rate and change the medium pressure at the flow meter to obtain the K coefficient calibration curve of the turbine flow meter at different flow points under different pressures.

[0032] According to an embodiment of the present invention, after step S7, the method further includes: substituting the calibration curve of the K coefficient of the turbine flow meter at different flow points under different pressures into the formula in step S3 to correct the fuel flow measured by the turbine flow meter under different pressures.

[0033] The positive and progressive effects of this invention are as follows:

[0034] The calibration test method of this invention for evaluating the influence of the K coefficient in turbine flow meters has the following advantages:

[0035] I. When applied to aero-engine flight testing, this method will improve the accuracy of fuel flow measurement. Fuel flow is a key parameter in calculating engine fuel consumption rate, and its measurement accuracy directly affects the evaluation results of fuel consumption performance indicators. Fuel consumption rate is one of the most important parameters for overall engine performance verification. This calibration and testing method supports the verification of overall engine performance and also supports the evaluation of the economic efficiency of civil aero-engines.

[0036] Second, the calibration and testing method described herein is aligned with the internationally advanced standard SAE ARP 4990, "TURBINE FLOW METERFUEL FLOW CALCULATIONS," and can effectively evaluate the influence of medium pressure on the K-coefficient of the turbine flow meter under test conditions. Feasible correction methods for the K-coefficient under different medium pressures are summarized. This can effectively improve the accuracy of fuel flow parameters in the full operating envelope of aero-engines, and establish a general methodological system, providing technical guidance for subsequent calculations of fuel consumption rates for civil engines of different aircraft types. Attached Figure Description

[0037] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein:

[0038] Figure 1 This is a schematic diagram of the calibration device used in the calibration test method of the present invention for evaluating the influence of the K coefficient of a turbine flow meter.

[0039] Figure 2 This is a schematic flowchart of the calibration test method of the present invention for evaluating the influence of the K coefficient of a turbine flow meter. Detailed Implementation

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0041] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the invention will now be described in detail, examples of which are shown in the drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts.

[0042] Furthermore, although the terminology used in this invention is selected from commonly known and used terms, some terms mentioned in this specification may have been selected by the applicant in his or her judgment, and their detailed meanings are explained in the relevant sections of the description herein.

[0043] Furthermore, the invention should be understood not only through the actual terminology used, but also through the meaning implied by each term.

[0044] like Figure 2 As shown, this invention discloses a calibration test method for evaluating the influence of the K-coefficient of a turbine flow meter, used to evaluate the effect of fuel medium pressure on the K-coefficient of the turbine flow meter, which includes the following steps:

[0045] Step S1: Modify the standard volumetric tubular liquid flow calibration station.

[0046] Preferably, in step S1, a high-pressure pump, a pressure regulating overflow valve, an accumulator, and a flow regulating valve are used to stably control the pressure of the fuel medium entering the inlet of the flow meter being measured, while simultaneously meeting the flow requirements of the flow meter being calibrated.

[0047] In step S1, the pressure control accuracy is ±0.05MPa, the flow rate fluctuation is ±20L / h, and the pressure of the medium flowing through the volume tube is kept at atmospheric pressure through the flow regulating valve and the back pressure regulating device.

[0048] Furthermore, a standard and a volumetric tube are connected in series after the flow meter being measured. A flow regulating valve and a water-cooled heat exchanger are installed before the volumetric tube, and a back pressure regulating device is installed after the volumetric tube, so that the pressure of the medium flowing through the volumetric tube is at normal temperature and pressure.

[0049] like Figure 1 As shown, the flow calibration bench consists of two parts: an oil source and a calibration test platform. The oil source provides sufficient pressurized clean fuel to the test platform, while the calibration test platform is used to install the flow meter under test, providing fuel that meets the required temperature, pressure, and flow rate, and measuring and calibrating the flow rate.

[0050] A high-pressure pump supplies pressurized fuel to the flow meter under test to meet calibration requirements. An accumulator compensates for pressure fluctuations at the pump outlet, stabilizing the pressure. An overflow valve then regulates the inlet pressure of the flow meter under test, providing system unloading and safety protection. A flow regulating valve adjusts the flow rate to meet the flow requirements of the flow meter being calibrated.

[0051] Preferably, the pressure control accuracy is ±0.05MPa, and the flow rate fluctuation is ±20L / h. A standard and a volumetric tube (a volumetric tube is a flow metering device composed of pipe sections with a constant cross-sectional area and a known volume) are connected in series after the flow meter being calibrated. A flow regulating valve and a water-cooled heat exchanger are installed before the volumetric tube, and a back pressure regulating device is installed after the volumetric tube to ensure that the pressure of the medium flowing through the volumetric tube is at normal temperature and pressure.

[0052] Step S2: Arrange a high-precision pressure measuring point P1 and a first density measuring point M1 in front of the flow meter to be calibrated, and collect the signals of the high-precision pressure measuring point, the first density measuring point, the frequency f of the flow meter to be calibrated, the volumetric flow rate of the volume tube, and the second density measuring point M2 in real time.

[0053] Preferably, in step S2, the high-precision pressure measuring point P1 and the first density measuring point M1 are arranged at a position with a length-to-diameter ratio of 10 before the flowmeter being calibrated.

[0054] Step S3: Obtain the K coefficient of the turbine flow meter under different medium pressures according to the calculation formula:

[0055]

[0056] Where f represents the flow meter output frequency in Hz; m 标 Q represents the standard fuel mass flow rate (kg / min) provided in the calibration test; 标 The standard volumetric flow rate of the volumetric tube during the calibration test is represented by L / min; ρ1 represents the density of the fuel medium at the flow meter (kg / m³). 3 ρ2 represents the density of the fuel medium at the volumetric pipe (kg / m³). 3 .

[0057] Step S3 involves calculating the K coefficient (the number of pulses emitted by the flow meter per unit volume of fluid flowing through it) to evaluate the impact of medium pressure on turbine flow meter measurements.

[0058] Parameters that can be directly measured during calibration include temperature, pressure, density, standard volumetric flow rate Q_standard, standard time t, and the number of pulses N output by the flowmeter being calibrated. Based on this data, further processing and calculations can be performed to obtain the K coefficient of the flowmeter and the measured flow rate value.

[0059] Furthermore, the step S3 is followed by the following steps:

[0060] Step S4: Calculate the standard flow rate value. The calculation formula is:

[0061]

[0062] in, Q represents the standard fuel mass flow rate (kg / h) provided in the calibration test; 标 ρ2 represents the standard volumetric flow rate of the volumetric tube during the calibration test (L / min); ρ2 represents the density reading at the medium density measuring point in the volumetric tube (kg / m2). 3 .

[0063] Step S5: Calculate the output frequency f of the flow meter being calibrated. 被校 The calculation formula is:

[0064]

[0065] Among them, f 被校 The frequency signal (Hz) output by the flowmeter being calibrated during the calibration test is represented by Hz; N represents the pulse signal output by the flowmeter being calibrated within time t.

[0066] Step S6: The formula for calculating the instrument coefficient K of the flow meter being calibrated is transformed as follows:

[0067]

[0068] Where ρ1 represents the density reading at point M1 of the flowmeter (kg / m³). 3K represents the instrument coefficient of the flow meter being calibrated.

[0069] Step S7: Set the fuel flow rate, change the medium pressure at the flow meter, and obtain the K coefficient calibration curve of the turbine flow meter at different flow points under different pressures.

[0070] The step S7 is followed by: substituting the K-coefficient calibration curve of the turbine flow meter at different flow points under different pressures into the formula in step S3 to correct the fuel flow measured by the turbine flow meter under different pressures.

[0071] As described in the above process, since the flowmeter's instrument coefficient (K coefficient) is related to the flowmeter's output frequency and the mass flow rate of the fluid flowing through it, the calibration test method of this invention obtains the K coefficient at different pressures by changing the medium pressure at the flowmeter. By controlling the pressure of the medium flowing through the flowmeter using a high-pressure pump, pressure regulating overflow valve, and accumulator before the flowmeter, the pressure can cover the range of medium pressure during actual flight tests, and the medium pressure exhibits high stability and minimal fluctuation. Simultaneously, to eliminate measurement errors caused by the medium pressure affecting the volume tube of the standard flow metering device, the calibration test method of this invention uses a flow regulating valve, a water-cooled heat exchanger, and a back pressure regulating device to ensure that the medium in the volume tube is at room temperature and pressure, guaranteeing the measurement accuracy of the standard.

[0072] The calibration test method described in this invention is based on the fact that the fuel mass is continuous within the entire calibration device, that is, the fuel mass flow rate passing through the flow meter under calibration and the volume tube is the same at the same time. After obtaining the standard mass flow rate value at the flow meter under calibration, the K coefficient of the turbine flow meter can be calculated. After processing and fitting the calibration data, the K coefficient-frequency f curve of the turbine flow meter under different medium pressures is formed.

[0073] In summary, this invention proposes a method for precisely controlling the pressure of the medium flowing through the flow meter being calibrated, achieving a pressure control accuracy of ±0.05MPa. Simultaneously, it ensures that the medium pressure at the standard volume tube is at atmospheric pressure, guaranteeing that the environmental conditions of the standard are consistent with those during traceability, thus ensuring the metrological accuracy of the standard. This overcomes the limitation of conventional calibration platforms in accurately adjusting higher fuel medium pressures.

[0074] Simultaneously, this invention also designs a method for calibrating the K-coefficient of a turbine flow meter under different fuel medium pressures. Considering that the medium oil pressure will cause changes in fuel density and viscosity, the calibration platform is built with continuous fuel mass, and the mass flow rate at the volume tube is the same as the mass flow rate at the flow meter being calibrated at the same time. By arranging density measuring points at the volume tube, the real-time fuel mass flow rate at the volume tube can be obtained. This mass flow rate can be used as the standard mass flow rate at the flow meter being calibrated. A high-pressure-resistant density measuring point is arranged in front of the flow meter being calibrated to obtain the real-time density value. At the same time, the frequency f of the flow meter being calibrated is collected, and the K-coefficient of the turbine flow meter under different medium pressures can be obtained using the formula.

[0075] For those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0076] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0077] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the present application requires more features than those mentioned in the claims. In fact, the embodiments have fewer features than all the features of a single embodiment disclosed above. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, the numerical parameters should take into account the prescribed significant digits and adopt a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of the present application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0078] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A calibration test method for evaluating the influence of the K coefficient in a turbine flow meter, characterized in that, The calibration test method is used to evaluate the effect of fuel medium pressure on the K coefficient of the turbine flow meter, and includes the following steps: S1. Modify the standard volumetric tubular liquid flow calibration bench; S2. Arrange a high-precision pressure measuring point P1 and a first density measuring point M1 in front of the flow meter to be calibrated, and collect the signals of the high-precision pressure measuring point, the first density measuring point, the frequency f of the flow meter to be calibrated, the volumetric flow rate of the volume tube, and the second density measuring point M2 in real time. S3. Obtain the K coefficient of the turbine flow meter under different medium pressures according to the calculation formula: Where f represents the flow meter output frequency in Hz; m 标 Q represents the standard fuel mass flow rate (kg / min) provided in the calibration test; 标 The standard volumetric flow rate of the volumetric tube during the calibration test is represented by L / min; ρ1 represents the density of the fuel medium at the flow meter (kg / m³). 3 ρ2 represents the density of the fuel medium at the volumetric pipe (kg / m³). 3 .

2. The calibration test method for evaluating the influence of the K coefficient of a turbine flow meter as described in claim 1, characterized in that, In step S1, a high-pressure pump, a pressure regulating overflow valve, an accumulator, and a flow regulating valve are used to stably control the pressure of the fuel medium entering the inlet of the flow meter being measured, while simultaneously meeting the flow requirements of the flow meter being calibrated.

3. The calibration test method for evaluating the influence of the K coefficient of a turbine flow meter as described in claim 2, characterized in that, In step S1, the pressure control accuracy is ±0.05 MPa, and the flow rate fluctuation is within acceptable limits. ±20L / h, and through the flow regulating valve and back pressure regulating device, the pressure of the medium flowing through the volume tube is kept at atmospheric pressure.

4. The calibration test method for evaluating the influence of the K coefficient of a turbine flow meter as described in claim 2, characterized in that, The flow meter being measured is connected in series with a standard and a volumetric tube. A flow regulating valve and a water-cooled heat exchanger are installed before the volumetric tube. A back pressure regulating device is installed after the volumetric tube so that the pressure of the medium flowing through the volumetric tube is at normal temperature and pressure.

5. The calibration test method for evaluating the influence of the K coefficient of a turbine flow meter as described in claim 1, characterized in that, In step S2, the high-precision pressure measuring point P1 and the first density measuring point M1 are arranged at a position with a length-to-diameter ratio of 10 in front of the flow meter being calibrated.

6. The calibration test method for evaluating the influence of the K coefficient of a turbine flow meter as described in claim 1, characterized in that, Following step S3, the following steps are also included: S4. Calculate the standard flow rate. The calculation formula is: in, Q represents the standard fuel mass flow rate (kg / h) provided in the calibration test; 标 ρ2 represents the standard volumetric flow rate of the volumetric tube during the calibration test (L / min); ρ2 represents the density reading at the medium density measuring point in the volumetric tube (kg / m2). 3 .

7. The calibration test method for evaluating the influence of the K coefficient of a turbine flow meter as described in claim 6, characterized in that, Following step S4, the following steps are also included: S5. Calculate the output frequency of the flow meter being calibrated, f 被校 The calculation formula is: Among them, f 被校 The frequency signal (Hz) output by the flowmeter being calibrated during the calibration test is represented by Hz; N represents the pulse signal output by the flowmeter being calibrated within time t.

8. The calibration test method for evaluating the influence of the K coefficient of a turbine flow meter as described in claim 7, characterized in that, Following step S5, the following steps are also included: S6. The formula for calculating the instrument coefficient K of the flow meter being calibrated is transformed as follows: Where ρ1 represents the density reading at point M1 of the flowmeter (kg / m³). 3 K represents the instrument coefficient of the flow meter being calibrated.

9. The calibration test method for evaluating the influence of the K coefficient of a turbine flow meter as described in claim 8, characterized in that, Following step S6, the following steps are also included: S7. Set the fuel flow rate and change the medium pressure at the flow meter to obtain the K coefficient calibration curve of the turbine flow meter at different flow points under different pressures.

10. The calibration test method for evaluating the influence of the K coefficient of a turbine flow meter as described in claim 9, characterized in that, The step S7 is followed by: substituting the K-coefficient calibration curve of the turbine flow meter at different flow points under different pressures into the formula in step S3 to correct the fuel flow measured by the turbine flow meter under different pressures.

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