Dynamic flow parallel measurement device and dynamic flow measurement method

Abstract

The application provides a dynamic flow parallel measurement device and a dynamic flow measurement method, and relates to the technical field of flow detection. The device comprises a processor, a differential pressure sensor, a temperature sensor, a displacement sensor, a first spring, a second spring, a piston, a first cylinder and a second cylinder. The differential pressure sensor, the temperature sensor and the displacement sensor are connected with the processor. The first end of the piston is connected with the first end of the first spring through the first spring seat and the first cylinder. The second end of the first spring is connected with the side wall of the first cylinder away from the piston. The second end of the piston is connected with the first end of the second spring through the second spring seat and the second cylinder. The second end of the second spring is connected with the side wall of the second cylinder away from the piston. A plurality of damping holes are arranged on the piston. The first cylinder is provided with a first inlet and outlet, and the second cylinder is provided with a second inlet and outlet. The application can measure the dynamic flow of any complex flow state, and has high dynamic response performance and measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of flow detection technology, and in particular to a dynamic flow parallel measurement device and a dynamic flow measurement method. Background Technology

[0002] Flow rate is one of the most important parameters in the field of fluid dynamics. Due to the influence of rotor inertia or fluid inertial forces, measuring dynamic flow rate has always been a challenging problem in this field. In particular, there is currently no universally accepted solution for measuring high-frequency, pulsating, asymmetrical flow rates.

[0003] With the continuous development of flow measurement technology, measurement and testing instruments are constantly being innovated, resulting in a wide variety of types and different testing characteristics. Currently, there are three main types of flow measurement instruments used for dynamic flow measurement: differential pressure / pressure flow meters, rotor flow meters, and unloaded hydraulic cylinder flow meters. Differential pressure / pressure flow meters have a fast response, but due to the influence of fluid inertia, the pressure difference caused by dynamic flow varies greatly, resulting in low measurement accuracy. Rotor flow meters, such as turbine flow meters and gear flow meters, mainly use metering components with large inertia. Improving the structure and using model compensation methods cannot fundamentally solve the problem of inertia. Unloaded hydraulic cylinders have good dynamic performance and high accuracy, showing good application prospects for dynamic flow measurement. However, due to the limited effective stroke range of the piston, they cannot be used for asymmetrical dynamic flow measurement with bias, resulting in significant limitations in their application. Summary of the Invention

[0004] The purpose of this invention is to provide a dynamic flow parallel measurement device and a dynamic flow measurement method, which can measure the dynamic flow of any complex flow state and has high dynamic response performance and measurement accuracy.

[0005] A dynamic flow parallel measurement device includes: a processor, a differential pressure sensor, a temperature sensor, a displacement sensor, a first spring, a second spring, a piston, a first cylinder, and a second cylinder;

[0006] The differential pressure sensor, the temperature sensor, and the displacement sensor are all connected to the processor;

[0007] The first spring is disposed in the first cylinder body, and the second spring is disposed in the second cylinder body;

[0008] The first end of the piston passes through the first cylinder and is connected to the first end of the first spring via the first spring seat; the second end of the first spring is connected to the side wall of the first cylinder away from the piston.

[0009] The second end of the piston passes through the second cylinder and is connected to the first end of the second spring via the second spring seat; the second end of the second spring is connected to the side wall of the second cylinder away from the piston.

[0010] The piston is provided with a plurality of damping holes; the first cylinder is provided with a first inlet and outlet, and the second cylinder is provided with a second inlet and outlet;

[0011] The displacement sensor is used to acquire the real-time displacement of the piston and send it to the processor;

[0012] The differential pressure sensor is used to acquire the real-time differential pressure across each of the damping orifices and send it to the processor;

[0013] The temperature sensor is used to acquire the real-time temperature of the liquid to be tested and send it to the processor;

[0014] The processor obtains the real-time dynamic flow rate of each damper based on the real-time displacement of the piston, the real-time temperature of the liquid to be measured, and the real-time pressure difference across each damping orifice.

[0015] Optionally, a gap seal or a low-damping dynamic seal is used between the piston and the first cylinder; a gap seal or a low-damping dynamic seal is used between the piston and the second cylinder.

[0016] The present invention also provides a method for dynamic flow measurement based on the above-mentioned dynamic flow parallel measurement device, comprising:

[0017] S1, based on the displacement sensor, the real-time displacement of the piston is obtained, and the real-time speed of the piston is obtained by differentiation;

[0018] S2, multiply the real-time movement speed of the piston by the effective area to obtain the real-time high-frequency dynamic flow component;

[0019] S3. The real-time pressure difference between the two ends of each damping orifice is obtained based on the differential pressure sensor. The real-time initial flow component of each damping orifice is calculated based on the real-time pressure difference between the two ends of each damping orifice.

[0020] S4. The real-time temperature of the liquid to be tested is obtained based on the temperature sensor, and the real-time temperature compensation coefficient is calculated based on the real-time temperature of the liquid to be tested.

[0021] S5, multiply the real-time initial flow component of each damping orifice by the real-time temperature compensation coefficient to obtain the real-time final flow component of each damping orifice.

[0022] S6, add the real-time final flow component of each damping orifice to the real-time high-frequency dynamic flow component to obtain the total real-time dynamic flow.

[0023] Optionally, the formula for calculating the real-time initial flow component of each damping orifice is:

[0024]

[0025] In the formula: A(τ) is the flow response function of unit step pressure difference, A′(τ) is the derivative of A(τ), Δp is the real-time pressure difference across the damping orifice, t is the time value when A(t) = 0.95A(∞), τ is the integral variable, and Q2 is the real-time initial flow component of the damping orifice.

[0026] Optionally, the formula for calculating the real-time temperature compensation coefficient is as follows:

[0027]

[0028] In the formula: T is the real-time temperature of the liquid being measured, β is the real-time temperature compensation coefficient, and a and b are correction coefficients. ref This represents the average historical temperature of the liquid being tested.

[0029] Alternatively, the flow response function A(τ) for a unit step pressure difference is:

[0030]

[0031] In the formula: k is the number of damping orifices, ν is the kinematic viscosity of the liquid being tested, l is the length of the damping orifice, r0 is the radius of the damping orifice, ρ is the density of the liquid being tested, and λ n Let α be the nth positive zero of the first-order zero Bessel function, and α be the calibration coefficient.

[0032] The effects of this invention are as follows:

[0033] The present invention relates to a dynamic flow parallel measurement device, comprising a processor, a differential pressure sensor, a temperature sensor, a displacement sensor, a first spring, a second spring, a piston, a first cylinder, and a second cylinder; it can measure dynamic flow in any complex flow pattern, has a wide bandwidth measurement function, and has a simple structure and wide range of applications. Attached Figure Description

[0034] Figure 1 This is a structural diagram of the dynamic flow parallel measurement device of the present invention;

[0035] Figure 2 This is a flowchart of the dynamic flow measurement method of the present invention.

[0036] In the diagram: 1. Processor; 2. Differential pressure sensor; 3. Temperature sensor; 4. Displacement sensor; 5. First spring; 6. Second spring; 7. Piston; 8. First cylinder; 9. Second cylinder; 10. First inlet / outlet; 11. Second inlet / outlet. Detailed Implementation

[0037] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0038] Figure 1 This is a structural diagram of the dynamic flow parallel measurement device of the present invention. Figure 1 As shown, the present invention provides a dynamic flow parallel measurement device, which includes: a processor 1, a differential pressure sensor 2, a temperature sensor 3, a displacement sensor 4, a first spring 5, a second spring 6, a piston 7, a first cylinder 8, and a second cylinder 9.

[0039] Differential pressure sensor 2, temperature sensor 3 and displacement sensor 4 are all connected to processor 1.

[0040] The first spring 5 is installed inside the first cylinder 8, and the second spring 6 is installed inside the second cylinder 9.

[0041] The first end of the piston 7 passes through the first cylinder 8 and is connected to the first end of the first spring 5 via the seat of the first spring 5; the second end of the first spring 5 is connected to the side wall of the first cylinder 8 away from the piston 7.

[0042] The second end of the piston 7 passes through the second cylinder 9 and is connected to the first end of the second spring 6 via the seat of the second spring 6; the second end of the second spring 6 is connected to the side wall of the second cylinder 9 away from the piston 7.

[0043] The piston 7 and the first cylinder 8 are sealed by a gap seal or a low-damping dynamic seal; the piston 7 and the second cylinder 9 are sealed by a gap seal or a low-damping dynamic seal.

[0044] The piston 7 has several damping holes; the first cylinder 8 has a first inlet / outlet 10, and the second cylinder 9 has a second inlet / outlet 11. The damping holes penetrate the piston.

[0045] Displacement sensor 4 is used to acquire the real-time displacement of piston 7 and send it to processor 1.

[0046] Differential pressure sensor 2 is used to acquire the real-time differential pressure at both ends of each damping orifice and send it to processor 1.

[0047] Temperature sensor 3 is used to acquire the real-time temperature of the liquid to be measured and send it to processor 1.

[0048] The processor 1 obtains the real-time dynamic flow rate of each damper based on the real-time displacement of the piston 7, the real-time temperature of the liquid to be measured, and the real-time pressure difference at both ends of each damping orifice.

[0049] Figure 2 This is a flowchart of the dynamic flow measurement method of the present invention. Figure 2 As shown, the present invention also provides a method for dynamic flow measurement based on a dynamic flow parallel measurement device, which includes:

[0050] S1: The real-time displacement of the piston is obtained based on the displacement sensor, and the real-time speed of the piston is obtained by differentiation.

[0051] S2 multiplies the real-time movement speed of the piston by the effective area to obtain the real-time high-frequency dynamic flow component.

[0052] The formula for calculating real-time high-frequency dynamic flow components is as follows:

[0053] Q1 = VA;

[0054] In the formula: A is the effective area of ​​the piston, V is the real-time movement speed of the piston, and Q1 is the real-time high-frequency dynamic flow component.

[0055] S3: Based on the differential pressure sensor, the real-time differential pressure at both ends of each damping orifice is obtained, and the real-time initial flow component of each damping orifice is calculated based on the real-time differential pressure at both ends of each damping orifice.

[0056] The formula for calculating the real-time initial flow component of each damping orifice is as follows:

[0057]

[0058] In the formula: A(τ) is the flow response function of unit step pressure difference, A′(τ) is the derivative of A(τ), Δp is the real-time pressure difference across the damping orifice, t is the time value when A(t) = 0.95A(∞), τ is the integral variable, and Q2 is the real-time initial flow component of the damping orifice.

[0059] The flow response function A(τ) for a unit step pressure difference is:

[0060]

[0061] In the formula: k is the number of damping orifices, ν is the kinematic viscosity of the liquid being tested, l is the length of the damping orifice, r0 is the radius of the damping orifice, ρ is the density of the liquid being tested, and λ n Let α be the nth positive zero of the first-order zero Bessel function, and α be the calibration coefficient.

[0062] S4: The real-time temperature of the liquid to be tested is obtained based on the temperature sensor, and the real-time temperature compensation coefficient is calculated based on the real-time temperature of the liquid to be tested.

[0063] The formula for calculating the real-time temperature compensation coefficient is as follows:

[0064]

[0065] In the formula: T is the real-time temperature of the liquid to be measured, β is the real-time temperature compensation coefficient, and a and b are correction coefficients, obtained by parameter identification based on measured damping orifice flow data at different oil temperatures. refThis represents the average historical temperature of the liquid being tested.

[0066] S5, multiply the real-time initial flow component of each damping orifice by the real-time temperature compensation coefficient to obtain the real-time final flow component of each damping orifice.

[0067] The formula for calculating the real-time final flow component of the damping orifice is as follows:

[0068]

[0069] In the formula: This represents the real-time final flow component of the damping orifice.

[0070] S6, add the real-time final flow component of each damping orifice to the real-time high-frequency dynamic flow component to obtain the total real-time dynamic flow.

[0071] The overall real-time dynamic traffic calculation formula is as follows:

[0072]

[0073] In the formula: Q represents the total real-time dynamic traffic.

[0074] Taking N32 hydraulic oil as an example, the steps are as follows:

[0075] The real-time displacement of the piston is acquired by a displacement sensor, and the real-time velocity V of the piston is obtained by differentiation. The displacement sensor has a range of ±13.5 mm and an accuracy of <0.25%. For example, at 2.9 s, the real-time displacement of the piston is 0.0023 m, and the real-time velocity of the piston is 0.0039 m / s.

[0076] The real-time high-frequency dynamic flow component is calculated based on the formula Q1=VA: at 2.9s, the real-time high-frequency dynamic flow component is 2.3L / min; A is taken as the diameter of the piston d=100mm.

[0077] Within a small temperature range (20℃), the step flow response curve of the damping orifice under unit pressure difference is calibrated to obtain the flow response function A(τ) under unit step pressure difference.

[0078]

[0079] In the formula: k is the number of damping orifices, taken as k = 2, ν is the kinematic viscosity of the liquid to be measured, ν = 15 × 10 -6 m 2 / s, l is the length of the damping orifice, taken as l = 50mm, r0 is the radius of the damping orifice, taken as r0 = 3.2mm, ρ is the density of the liquid to be measured, taken as ρ = 890kg / m³ 3 , λ nLet α be the nth positive zero of the first-order zero Bessel function, and let α be the calibration coefficient, α = 0.92.

[0080] The stiffness of the first and second springs is 50 N / mm, and the piston stroke is ±10 mm.

[0081] Based on formula Calculate the real-time initial flow component of the damping orifice. The differential pressure sensor has a range of 0–0.15 MPa and an accuracy of 0.25%. For example, at 2.9 s, the pressure difference across the damping orifice is 4.85 x 10⁻⁶. 4 pa.

[0082] Introducing a real-time temperature compensation coefficient β, based on the formula The real-time temperature compensation coefficient was calculated, with b set to 1.1 and a set to 0.92.

[0083] The formula for calculating the real-time final flow component of the damping orifice is as follows: At 2.9s, the real-time final flow rate of the damping orifice is 6.7L / min.

[0084] Based on formula The total real-time dynamic flow rate was calculated to be 9 L / min.

[0085] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A dynamic flow parallel measurement device, characterized in that, It includes: Processor, differential pressure sensor, temperature sensor, displacement sensor, first spring, second spring, piston, first cylinder and second cylinder; The differential pressure sensor, the temperature sensor, and the displacement sensor are all connected to the processor; The first spring is disposed in the first cylinder body, and the second spring is disposed in the second cylinder body; The first end of the piston passes through the first cylinder and is connected to the first end of the first spring via a first spring seat; the second end of the first spring is connected to the side wall of the first cylinder away from the piston. The second end of the piston passes through the second cylinder and is connected to the first end of the second spring via the second spring seat; the second end of the second spring is connected to the side wall of the second cylinder away from the piston. The piston is provided with a plurality of damping holes; the first cylinder is provided with a first inlet and outlet, and the second cylinder is provided with a second inlet and outlet; The displacement sensor is used to acquire the real-time displacement of the piston and send it to the processor; The differential pressure sensor is used to acquire the real-time differential pressure across each of the damping orifices and send it to the processor; The temperature sensor is used to acquire the real-time temperature of the liquid to be tested and send it to the processor; The processor obtains the real-time dynamic flow rate of each damper based on the real-time displacement of the piston, the real-time temperature of the liquid to be measured, and the real-time pressure difference across each damping orifice.

2. The dynamic flow parallel measurement device according to claim 1, characterized in that, The piston and the first cylinder are sealed by a gap seal or a low-damping dynamic seal; the piston and the second cylinder are sealed by a gap seal or a low-damping dynamic seal.

3. A method for dynamic flow measurement based on the dynamic flow parallel measurement device according to claim 1 or 2, characterized in that, It includes: S1, based on the displacement sensor, the real-time displacement of the piston is obtained, and the real-time speed of the piston is obtained by differentiation; S2, multiply the real-time movement speed of the piston by the effective area to obtain the real-time high-frequency dynamic flow component; S3. The real-time pressure difference between the two ends of each damping orifice is obtained based on the differential pressure sensor. The real-time initial flow component of each damping orifice is calculated based on the real-time pressure difference between the two ends of each damping orifice. S4. The real-time temperature of the liquid to be tested is obtained based on the temperature sensor, and the real-time temperature compensation coefficient is calculated based on the real-time temperature of the liquid to be tested. S5, multiply the real-time initial flow component of each damping orifice by the real-time temperature compensation coefficient to obtain the real-time final flow component of each damping orifice. S6, add the real-time final flow component of each damping orifice to the real-time high-frequency dynamic flow component to obtain the total real-time dynamic flow.

4. The method for dynamic flow measurement according to claim 3, characterized in that, The formula for calculating the real-time initial flow component of each damping orifice is as follows: In the formula: A(τ) is the flow response function of unit step pressure difference, A′(τ) is the derivative of A(τ), Δp is the real-time pressure difference across the damping orifice, t is the time value when A(t) = 0.95A(∞), τ is the integral variable, and Q2 is the real-time initial flow component of the damping orifice.

5. The method for dynamic flow measurement according to claim 3, characterized in that, The formula for calculating the real-time temperature compensation coefficient is as follows: In the formula: T is the real-time temperature of the liquid being measured, β is the real-time temperature compensation coefficient, and a and b are correction coefficients. ref This represents the average historical temperature of the liquid being tested.

6. The method for dynamic flow measurement according to claim 4, characterized in that, The flow response function A(τ) for a unit step pressure difference is: In the formula: k is the number of damping orifices, ν is the kinematic viscosity of the liquid being tested, l is the length of the damping orifice, r0 is the radius of the damping orifice, ρ is the density of the liquid being tested, and λ n Let α be the nth positive zero of the first-order zero Bessel function, and α be the calibration coefficient.

Images