Flow measurement method and device, flowmeter and storage medium

Abstract

The present invention relates to the technical field of flow measurement, and discloses a flow measurement method and device, a flowmeter and a storage medium. The flow measurement method includes: obtaining the temperature difference detected by a thermal flow detection component in the flowmeter. The flowmeter includes a fluid channel and a flow detection unit. The fluid channel includes a main flow channel and a bypass flow channel. The target fluid channel is connected to the main flow channel through a pipeline. A throttling component is arranged in the main flow channel. The inlet of the bypass flow channel is connected to the upstream pipeline of the throttling component, and the outlet of the bypass flow channel is connected to the downstream pipeline of the throttling component. The flow detection unit is located in the bypass channel and includes a thermal flow detection component and a differential pressure flow detection component; obtaining the pressure difference detected by the differential pressure flow detection component; and determining the flow rate of the target fluid channel based on the temperature difference, the pressure difference and the physical property parameters of the fluid medium in the target fluid channel. Thereby, the flow measurement is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of flow measurement, and in particular to a flow measurement method and device, a flow meter and a storage medium. Background Art

[0002] There are two common types of flow detection in existing flow measurement methods, one is a thermal flow measurement method, and the other is a differential pressure flow measurement method.

[0003] The thermal flow measurement method is a technology that directly measures the mass flow of the fluid based on the heat exchange relationship between the fluid and the sensor heat source. Its output result is related to the mass flow of the measured medium and the physical properties of the medium. The measurement principle of the thermal flow measurement method determines that it will have a large deviation in applications where the medium composition fluctuates greatly.

[0004] The differential pressure flow measurement method is a measurement technology with complete design, calibration and use method standards and specifications. It can directly calculate the flow rate based on the differential pressure generated by the fluid flow blocker installed in the pipeline, the medium conditions and the geometric dimensions of the flow blocker. The differential pressure flow measurement method also has high requirements for the stability of the medium components. When the fluid composition changes, it will produce large deviations due to changes in the medium density.

[0005] Both the thermal flow measurement method and the differential pressure flow measurement method are not suitable for application scenarios where the medium components are unstable. Summary of the invention

[0006] Embodiments of the present invention provide a flow measurement method and device, a flow meter, and a storage medium, which are applicable to application scenarios where medium components are unstable.

[0007] In a first aspect, an embodiment of the present invention provides a flow measurement method for measuring the flow in a target fluid channel, the flow measurement method comprising: obtaining a temperature difference detected by a thermal flow detection component in a flow meter, wherein the flow meter comprises a fluid channel and a flow detection unit, the fluid channel comprises a main flow channel and a bypass flow channel, the target fluid channel is connected to the main flow channel pipeline, a throttling component is built into the main flow channel, an inlet of the bypass flow channel is connected to an upstream pipeline of the throttling component, an outlet of the bypass flow channel is connected to a downstream pipeline of the throttling component, the flow detection unit is in the bypass channel, the flow detection unit comprises a thermal flow detection component and a differential pressure flow detection component; obtaining the pressure difference detected by the differential pressure flow detection component; and determining the flow of the target fluid channel based on the temperature difference, the pressure difference and the physical properties of the fluid medium in the target fluid channel.

[0008] Optionally, the flow rate detection unit further includes a temperature detection component and a pressure detection component. The temperature detection component is used to detect the temperature in the bypass flow channel, and the pressure detection component is used to detect the pressure in the bypass flow channel. Among them, before determining the flow rate of the target fluid channel based on the temperature difference, pressure difference, and physical property parameters of the fluid medium in the target fluid channel, the flow rate measurement method further includes: obtaining the temperature detected by the temperature detection component; and obtaining the pressure detected by the pressure detection component. Among them, determining the flow rate of the target fluid channel based on the temperature difference, pressure difference, and physical property parameters of the fluid medium in the target fluid channel includes: determining the flow rate of the target fluid channel under standard conditions based on the temperature, pressure, temperature difference, pressure difference, and physical property parameters of the fluid medium in the target fluid channel.

[0009] Optionally, determining the flow rate of the target fluid channel based on the temperature difference, pressure difference, and physical property parameters of the fluid medium in the target fluid channel includes: determining the current thermal flow rate and the current differential pressure flow rate of the target fluid channel, where the current thermal flow rate is determined based on the thermal flow rate measurement mode in combination with the temperature difference, pressure difference, and physical property parameters of the fluid medium in the target fluid channel, and the current differential pressure flow rate is determined based on the differential pressure flow rate measurement mode in combination with the temperature difference, pressure difference, and physical property parameters of the fluid medium in the target fluid channel; determining the current thermal flow rate or the current differential pressure flow rate as the actual measured flow rate of the target fluid channel based on the current thermal flow rate and / or the current differential pressure flow rate and the flow rate measurement mode determination rule, so as to determine the flow rate of the target fluid channel.

[0010] Optionally, determining the current thermal flow rate or the current differential pressure flow rate as the actual measured flow rate of the target fluid channel based on the current thermal flow rate and / or the current differential pressure flow rate and the flow rate measurement mode determination rule includes: determining a comparison flow rate based on the current thermal flow rate and / or the current differential pressure flow rate; determining the current thermal flow rate or the current differential pressure flow rate as the actual measured flow rate of the target fluid channel based on the comparison flow rate and the flow rate measurement mode determination rule, so as to determine the flow rate of the target fluid channel.

[0011] Optionally, the flow rate measurement mode determination rule includes: determining the current differential pressure flow rate as the actual measured flow rate when any of the following conditions is met: the comparison flow rate is greater than or equal to the preset flow rate threshold, the comparison flow rate is greater than or equal to the upper limit of the preset flow rate threshold range; and / or determining the current thermal flow rate as the actual measured flow rate when any of the following conditions is met: the comparison flow rate is less than the preset flow rate threshold, the comparison flow rate is less than or equal to the lower limit of the preset flow rate threshold range.

[0012] Optionally, the physical property parameters include thermal conductivity, density, and specific heat capacity.

[0013] In a second aspect, an embodiment of the present invention further provides a flow measurement device for measuring the flow rate in a target fluid channel. The flow measurement device includes: a memory; and a processor. The memory is used to store a computer program, and the processor is used to implement the above-mentioned flow measurement method by running the computer program stored in the memory.

[0014] In a third aspect, an embodiment of the present invention further provides a storage medium with a computer program stored thereon. When the computer program is run by a processor, the above-mentioned flow measurement method is implemented.

[0015] In a fourth aspect, an embodiment of the present invention further provides a flowmeter, which includes: a fluid channel including a main flow channel and a bypass flow channel. The target fluid channel is connected to the main flow channel through a pipeline. A throttling component is disposed in the main flow channel. The inlet of the bypass flow channel is connected to the upstream pipeline of the throttling component, and the outlet of the bypass flow channel is connected to the downstream pipeline of the throttling component; and a flow detection unit located in the bypass channel. The flow detection unit includes a thermal flow detection component, a differential pressure flow detection component, and a physical property parameter detection component; and a control module for executing the above-mentioned flow measurement method.

[0016] Optionally, the flow detection unit further includes: a substrate including a first gas through-hole and a second gas through-hole. The substrate divides the bypass channel into a micro-channel and a differential pressure detection chamber. The thermal flow detection component and the differential pressure flow detection component are integrated on both sides of the substrate, and the physical property parameter detection component and the differential pressure flow detection component are integrated on the same side of the substrate. The differential pressure flow detection component divides the differential pressure detection chamber into a first differential pressure detection chamber and a second differential pressure detection chamber. The fluid medium in the micro-channel flows through the thermal flow detection component, and the gas in the micro-channel enters the first differential pressure detection chamber through the first gas through-hole and enters the second differential pressure detection chamber through the second gas through-hole.

[0017] Optionally, the flow detection unit further includes: a temperature detection component for detecting the temperature in the bypass flow channel; and a pressure detection component for detecting the pressure in the bypass flow channel.

[0018] Optionally, at least one rectifying component is further disposed in the main flow channel, and at least one of the at least one rectifying component is located upstream of the upstream connection position of the bypass flow channel and the main flow channel.

[0019] Through the above technical solution, in combination with the physical property parameters of the fluid medium, and by means of the temperature difference detected by the thermal flow detection component and the pressure difference detected by the differential pressure flow detection component, the flow rate of the target fluid channel is determined. In this way, the flow rate measurement is achieved. In addition, for fluid media with different medium components, the physical property parameters are different. When measuring the flow rate, considering the physical property parameters of the fluid medium, even if the medium component of the fluid medium changes, the flow rate can still be measured, enabling the technical solution provided by the embodiments of the present invention to be applicable to application scenarios where the medium component is unstable, thus expanding the application scope.

[0020] Other features and advantages of the present invention will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0022] Figure 1 is a flowchart of a flow rate measurement method provided by an embodiment of the present invention;

[0023] Figure 2 is a partial structural schematic diagram of a flowmeter provided by another embodiment of the present invention;

[0024] Figure 3 is a partial structural schematic diagram of a flowmeter provided by still another embodiment of the present invention;

[0025] Figure 4 is a partial structural schematic diagram of a flowmeter provided by yet another embodiment of the present invention;

[0026] Figure 5 is a cross-sectional structural schematic diagram of a flow detection unit provided by yet another embodiment of the present invention;

[0027] Figure 6 is a cross-sectional structural schematic diagram of a flow detection unit provided by yet another embodiment of the present invention;

[0028] Figure 7 is a partial composition schematic diagram of a flowmeter provided by yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] The thermal flow measurement method is very sensitive to the response of tiny fluid flows. However, in the high flow rate region, as the mass flow rate increases, the response sensitivity of the output signal of the sensor continuously decreases and tends to saturate. Thus, the thermal flow measurement method is mainly used in medium and small flow rate or medium and low pressure applications. In addition, the measurement principle of the thermal flow measurement method also determines that there will be large deviations in applications where the medium composition fluctuates greatly. The differential pressure flow measurement method has a clear principle, a simple structure, and is widely used. In addition, the measurement range of the differential pressure flow measurement method is relatively narrow (generally only 3:1 to 4:1).

[0031] Both the thermal flow measurement method and the differential pressure flow measurement method have high requirements for the stability of the medium and are not applicable to occasions where the composition is variable and unpredictable. In view of this problem, the embodiments of the present invention propose corresponding technical solutions to solve the problem.

[0032] In a first aspect, an embodiment of the present invention provides a flow measurement method.

[0033] Figure 1 is a flowchart of a flow measurement method provided by an embodiment of the present invention. As Figure 1 shown, the flow measurement method includes the following. Among them, the flow measurement method is used to measure the flow rate in the target fluid channel.

[0034] In step S10, obtain the temperature difference detected by the thermal flow detection component in the flowmeter. The flowmeter includes a fluid channel and a flow detection unit. The fluid channel includes a main flow channel and a bypass flow channel. The target fluid channel is connected to the main flow channel through pipelines. A throttling component is built in the main flow channel. The inlet of the bypass flow channel is connected to the upstream pipeline of the throttling component, and the outlet of the bypass flow channel is connected to the downstream pipeline of the throttling component. The flow detection unit is located in the bypass channel. The flow detection unit includes a thermal flow detection component and a differential pressure flow detection component.

[0035] Optionally, in an embodiment of the present invention, the thermal flow detection component may be a MEMS thermal distributed flow sensor. The thermal flow detection component includes a heating element and at least one pair of temperature measurement elements, and the temperature measurement elements are symmetrically distributed relative to the heating element. Optionally, the heating element is heated by applying a constant power or a constant current or a constant voltage, and the temperature difference change caused by fluid flow is detected by the upstream and downstream temperature measurement elements.

[0036] Optionally, the temperature of the heating element is controlled by a constant temperature difference control circuit or a constant temperature control circuit to be a fixed difference relative to the ambient temperature, or the heating element is maintained at a constant temperature, and the temperature difference change caused by fluid flow is detected by the upstream and downstream symmetrically distributed temperature measurement elements.

[0037] In step S11, obtain the pressure difference detected by the differential pressure flow detection component.

[0038] In step S12, based on the temperature difference, the pressure difference, and the physical property parameters of the fluid medium in the target fluid channel, the flow rate of the target fluid channel is determined. The physical property parameters of the fluid medium can be physical quantities that can reflect the physical properties of the fluid medium. The physical property parameters can be obtained through a physical property sensor. Optionally, in the embodiments of the present invention, the physical property parameters may include at least one of the following: thermal conductivity, density, and specific heat capacity. Optionally, the density may be an average density. Optionally, the specific heat capacity may be a specific heat capacity at constant pressure.

[0039] Through the above technical solution, in combination with the physical property parameters of the fluid medium, by means of the temperature difference detected by the thermal flow detection component and the pressure difference detected by the differential pressure flow detection component, the flow rate of the target fluid channel is determined. In this way, the flow rate measurement is achieved. In addition, for fluid media with different medium components, the physical property parameters are different. When measuring the flow rate, considering the physical property parameters of the fluid medium, even if the medium component of the fluid medium changes, the flow rate can still be measured, so that the technical solution provided by the embodiments of the present invention can be applied to application scenarios where the medium component is unstable, expanding the application range. In addition, the technical solution provided by the embodiments of the present invention combines the temperature difference detected by the thermal flow detection component and the pressure difference detected by the differential pressure flow detection component, that is, combines the thermal flow measurement principle and the differential pressure flow measurement principle, improves the measurement accuracy, expands the range, improves the measurement accuracy and the measurement range, and greatly expands the application range.

[0040] Optionally, in the embodiments of the present invention, the flow rate of the target fluid channel can be determined according to the following content.

[0041] Determine the current thermal flow rate and the current differential pressure flow rate of the target fluid channel. Among them, the current thermal flow rate is determined based on the thermal flow measurement mode in combination with the temperature difference, the pressure difference, and the physical property parameters of the fluid medium in the target fluid channel, and the current differential pressure flow rate is determined based on the differential pressure flow measurement mode in combination with the temperature difference, the pressure difference, and the physical property parameters of the fluid medium in the target fluid channel. Among them, the thermal flow measurement mode is based on the thermal flow measurement method, and combines the temperature difference detected by the thermal flow detection component, the pressure difference detected by the differential pressure flow detection component, and the physical property parameters to calculate the flow rate. In addition, the differential pressure flow detection mode is based on the differential pressure flow measurement method, and combines the temperature difference detected by the thermal flow detection component, the pressure difference detected by the differential pressure flow detection component, and the physical property parameters to calculate the flow rate.

[0042] Based on the current thermal flow rate and / or the current differential pressure flow rate and the flow rate measurement mode determination rule, determine the current thermal flow rate or the current differential pressure flow rate as the actual measured flow rate of the target fluid channel to determine the flow rate of the target fluid channel. Among them, the flow rate measurement mode determination rule indicates the conditions under which the current differential pressure flow rate is determined as the actual measured flow rate and the conditions under which the current differential pressure flow rate is determined as the actual measured flow rate.

[0043] Optionally, in the embodiments of the present invention, determining the current thermal flow rate based on the thermal flow measurement mode in combination with the temperature difference, pressure difference, and physical property parameters of the fluid medium in the target fluid channel may be to determine the current thermal flow rate based on the thermal flow measurement formula, where the independent variables in the thermal flow measurement formula are the temperature difference, pressure difference, and physical property parameters, and the dependent variable in the thermal flow measurement formula is the flow rate.

[0044] Optionally, in the embodiments of the present invention, the thermal flow measurement formula may be Formula 1. Formula 1: Where Q 热 is the total flow rate of the target fluid channel obtained based on the thermal flow measurement mode; Q 旁 is the bypass flow rate; ΔT is the temperature difference; λ0 is the thermal conductivity of the reference fluid in the calibration stage; (ρ·C p )0 is the volumetric heat capacity of the reference fluid in the calibration stage; λ is the thermal conductivity of the actual fluid flowing in the target fluid channel for which the flow rate is actually to be measured; ρ·C p is the volumetric heat capacity of the actual fluid; is the flow rate split ratio between the bypass flow channel and the main flow channel; ΔP is the pressure difference of the actual fluid; (ΔP)0 is the pressure difference corresponding to the reference fluid flow rate Q0 or the temperature difference (ΔT)0 in the calibration stage, Q0 is the standard flow rate set or provided for the reference fluid standard device during calibration in the calibration stage, and (ΔT)0 is the temperature difference detected by the thermal flow detection component when the standard flow rate Q0 established by the standard device in the calibration stage. Among them, the flow rate split ratio is determined through the flow rate calibration process. In addition, for any fluid medium, the volumetric heat capacity is the product of density and specific heat capacity. The volumetric heat capacity (ρ·C p )0 of the reference fluid in the calibration stage can be obtained by multiplying the density ρ0 of the reference fluid in the calibration stage and the specific heat capacity at constant pressure C p0 , and the volumetric heat capacity ρ·C p of the actual fluid can be obtained by multiplying the density ρ of the actual fluid and the specific heat capacity at constant pressure C p .

[0045] For the bypass flow channel design, there is the following quantitative relationship between the total flow rate of the target fluid channel and the main flow rate of the main flow channel and the bypass flow rate of the bypass flow channel:

[0046]

[0047] Where Q 总 is the total flow rate, including but not limited to mass flow rate, volume flow rate, standard condition volume flow rate (101.325 kPa, 20 °C); Q 旁 is the flow rate of the bypass flow channel; Q 主 is the flow rate of the main flow channel; is the flow rate split ratio between the bypass flow channel and the main flow channel. Among them, the flow rate split ratio is determined through the flow rate calibration process.

[0048] Based on the above quantitative relationship, the total flow rate calculation formula can be obtained:

[0049] Thus, when the calculation formula of the bypass flow rate is determined, according to the conversion relationship between the total flow rate and the bypass flow rate above, the calculation formula of the total flow rate can be obtained.

[0050] Optionally, in the embodiments of the present invention, Formula 1 can be obtained based on any one of Formulas 11 to 14.

[0051] Formula 11: where Q 11 is the flow rate, including but not limited to mass flow rate, volume flow rate, and standard condition volume flow rate (101.325 kPa, 20 °C). ΔT is the temperature difference detected by the thermal flow detection component. K1 is the instrument coefficient of the thermal flow detection component, which is determined during the factory calibration stage. A is the heat conduction coefficient between the heating element in the thermal flow detection component and the environment, which is related to physical property parameters such as the thermal conductivity λ1 and viscosity coefficient μ1 of the fluid medium. Usually, the heat conduction coefficient A can be approximately represented by the thermal conductivity coefficient of the fluid medium, while ignoring the influence of viscosity characteristics. (ρ·C p )1 is the volume heat capacity of the fluid medium, which is the product of C p1 and ρ1. C p1 is the specific heat capacity at constant pressure of the fluid medium. ρ1 is the density of the fluid medium (preferably, the average density under working conditions can be used). The flow rate obtained based on the thermal flow detection component is related to some physical properties of the fluid medium, such as λ1, ρ1, and C p1 etc. ΔT is the temperature difference between the temperature measuring elements upstream and downstream of the heating element in the thermal flow detection component when the heating element is in a constant temperature difference or constant power mode, and the temperature difference can be detected and obtained through a Wheatstone bridge.

[0052] Optionally, Formula 11 can be applied when the fluid medium is at a medium or low flow rate and in a laminar flow state. At this time, there is an approximately linear relationship between the bypass flow rate in the bypass flow channel and the temperature difference detected by the thermal flow detection component.

[0053] Formula 12:

[0054] where Q 12is the flow rate. ΔT is the temperature difference detected by the thermal flow detection component. K2, K3, and K4 depend on the geometric dimensions, circuit design, and gas characteristics of the thermal flow detection component. For example, the distance between the temperature measurement element and the heating element in the thermal flow detection component, the relative magnitude of the resistance value of the temperature measurement element, and the physical properties of the fluid medium such as the thermal conductivity λ1, volumetric heat capacity (ρ·C p )1, etc. K5 is mainly affected by the flow state, such as the Reynolds number (a function of the fluid mass flow rate and viscosity coefficient μ1), etc. When the measured flow rate range is wide and the Reynolds number changes greatly, the coefficient K5 is not a fixed value and changes with the change of the Reynolds number. The introduction of viscosity characteristics can further improve the accuracy of the measurement result.

[0055] Equation 12 can be applied when there is a non-linear relationship between the flow rate detected by the thermal flow detection component and the temperature difference. As the fluid flow rate increases, there is a non-linear relationship between the flow rate detected by the thermal flow detection component and the temperature difference, and the influence brought by the fluid viscosity becomes more significant. Based on Equation 12, the flow rate detection is more accurate.

[0056] Equation 13:

[0057] Equation 14:

[0058] where Q 13 , Q 14 both represent the flow rate, including but not limited to mass flow rate, volume flow rate, and standard condition volume flow rate. ΔT is the temperature difference detected by the thermal flow detection component. P1, P2, P3, a1, a2, a3 are coefficients related to the geometric structures of the thermal flow detection component and the flow channel, and the physical properties of the fluid medium (λ1, (ρ·C p )1, μ1, etc.). For the explanations of λ1, (ρ·C p )1, μ1, reference can be made to the above content. P1, P2, P3, a1, a2, a3 can be obtained by data fitting.

[0059] For the pressure loss generated by the fluid medium passing through the bypass flow channel of the thermal flow detection component, based on the Poiseuille equation, there is the following relationship between the volume flow rate in the bypass flow channel and the pressure difference:

[0060]

[0061]

[0062] where Q 旁v is the volume flow rate of the fluid in the bypass flow channel; Q 旁m$Q$ is the mass flow rate of the fluid in the bypass channel; $\Delta P$ is the pressure drop generated by the fluid passing through the bypass channel or the differential pressure between the inlet and outlet of the bypass channel. In other words, $\Delta P$ is the differential pressure detected by the differential pressure flow detection component; $S$ is the cross-sectional area of the bypass channel, $L$ is the length of the bypass channel; $\mu$ is the viscosity coefficient of the fluid medium; $\rho_1$ is the density of the fluid medium (preferably, the average density under working conditions); $\pi$ is the pi coefficient 3.14.

[0063] For a known fluid flow channel, the viscosity characteristics of different fluid media can be characterized by measuring the differential pressure of the bypass channel. The relationship is as follows: Based on this relationship, the conversion relationship between the viscosity coefficient and the differential pressure can be obtained. Among them, $\mu_0$ represents the viscosity coefficient of the reference fluid in the calibration stage, $\mu_1$ represents the viscosity coefficient of the actual fluid; $(\Delta P)_0$ is the differential pressure corresponding to the reference fluid flow rate $Q_0$ or the temperature difference $(\Delta T)_0$ in the calibration stage, $Q_0$ is the standard flow rate set or provided for the reference fluid standard device during calibration in the calibration stage, and $(\Delta T)_0$ is the temperature difference detected by the thermal flow detection component when the standard flow rate $Q_0$ established by the standard device in the calibration stage. $(\Delta P)_0$ and $(\Delta P)_1$ are the differential pressures corresponding to the two fluid media (reference fluid and actual fluid) at the same flow rate $Q_0$.

[0064] When the differential pressure flow detection component detects that the differential pressure is the pressure drop generated by the fluid passing through the bypass channel where the thermal flow detection component is placed, formulas 11 to 14 can be extended to:

[0065] Formula 15: $Q$ 15 $= f(\Delta T, \Delta P, \lambda_1, (\rho \cdot C$ p )_1)$

[0066] Thus, for a known channel design, by integrating the thermal conductivity, density, and specific heat capacity at constant pressure of the fluid medium, and combining the temperature difference $\Delta T$ and differential pressure $\Delta P$ information, more accurate flow rate information can be obtained.

[0067] It should be noted that formula 15 is the formula obtained in the calibration stage. In other words, formula 15 can be updated to formula 16: $Q$ 16 $= f(\Delta T, (\Delta P)_0, \lambda_0, (\rho \cdot C$ p )_0)$. $\lambda_0$ is the thermal conductivity of the reference fluid in the calibration stage; $(\Delta P)_0$ is the differential pressure corresponding to the reference fluid flow rate $Q_0$ or the temperature difference $(\Delta T)_0$ in the calibration stage, $Q_0$ is the standard flow rate set or provided for the reference fluid standard device during calibration in the calibration stage, and $(\Delta T)_0$ is the temperature difference detected by the thermal flow detection component when the standard flow rate $Q_0$ established by the standard device in the calibration stage; $(\rho \cdot C$ p )_0$ is the volume heat capacity of the reference fluid in the calibration stage. The volume heat capacity of the reference fluid in the calibration stage $(\rho \cdot C$ p)0 can be obtained by using the density ρ0 and the specific heat capacity at constant pressure C of the reference fluid in the calibration stage p0 in the product.

[0068] When the fluid composition changes, the physical properties such as thermal conductivity, specific heat capacity, density, and viscosity coefficient of the actual fluid change relative to the reference fluid in the calibration stage. By comparing the physical property differences between the physical property parameters such as the thermal conductivity, density, and specific heat capacity of the actual fluid and those of the reference fluid used in the calibration stage, and combining the differential pressure information obtained by the differential pressure detection component, the differential changes brought about by the change in the fluid composition of the actual fluid are corrected. Thus, based on Equation 16, Equation 17 is obtained: Q 旁 = f(ΔT, (ΔP) / (ΔP)0, λ / λ0, (ρ·C p ) / (ρ·C p )0).

[0069] Based on Equation 17 and Equation 1 is obtained:

[0070] Optionally, in the embodiments of the present invention,

[0071] wherein, m1, m2, and m3 are parameters determined according to various actual gas test experiments.

[0072] According to the temperature difference ΔT signal detected by the thermal flow detection component, the corresponding flow rate is obtained based on the calibration relationship (Equation 16) between the reference fluid flow rate Q and the temperature difference ΔT obtained in advance in the calibration stage. Then, according to the differential pressure ΔP, thermal conductivity λ, volume heat capacity (ρ·C p ) and other fluid medium-related information detected simultaneously by the differential pressure flow detection component and the physical property parameter detection component, the true flow rate of the target fluid channel is obtained according to Equation 1.

[0073] Determining the current thermal flow rate of the target fluid channel based on Equation 1 is to couple and process the thermal flow rate signal detected by the thermal flow detection component and the differential pressure flow rate signal detected by the differential pressure flow detection component, and use the temperature difference signal, pressure difference signal, and physical property parameters to correct and calculate the flow rate obtained by the thermal flow measurement method to obtain the true flow rate information. If the current thermal flow rate is determined as the actual measured flow rate of the target fluid channel, based on the pressure difference signal, the flow rate obtained by the thermal flow measurement method is corrected and calculated, so that the thermal flow measurement method further considers the component, and is more applicable to the application scenario where the medium component is unstable. In addition, the pressure difference signal is related to the viscosity. Based on the pressure difference signal, the flow rate obtained by the thermal flow measurement method is corrected and calculated, taking the viscosity coefficient into account, and further improving the measurement accuracy.

[0074] Optionally, in the embodiments of the present invention, based on the differential pressure flow measurement mode, the current differential pressure flow is determined by combining the temperature difference, the differential pressure, and the physical property parameters of the fluid medium in the target fluid channel, and the current differential pressure flow can be determined based on the differential pressure flow measurement formula. Among them, the independent variables in the differential pressure flow measurement formula are the temperature difference, the differential pressure, and the physical property parameters, and the dependent variable in the differential pressure flow measurement formula is the flow rate.

[0075] Optionally, in the embodiments of the present invention, the differential pressure flow measurement formula can be Formula 2. Formula 2:

[0076] Where Q 差 is the total flow rate of the target fluid channel obtained based on the differential pressure flow measurement mode; Q 主 is the main flow rate, Q 旁 is the bypass flow rate; ΔT is the temperature difference; λ0 is the thermal conductivity of the reference fluid in the calibration stage; (ρ·C p )0 is the volumetric heat capacity of the reference fluid in the calibration stage; λ is the thermal conductivity of the actual fluid flowing in the target fluid channel of the actual flow rate to be measured; ρ·C p is the volumetric heat capacity of the actual fluid; ΔP is the differential pressure of the actual fluid; (ΔP)0 is the differential pressure corresponding to the reference fluid flow rate Q0 or the temperature difference (ΔT)0 in the calibration stage, Q0 is the standard flow rate set or provided for the reference fluid standard device during calibration in the calibration stage, and (ΔT)0 is the temperature difference detected by the thermal flow detection component when the standard flow rate Q0 established by the standard device in the calibration stage; is the flow rate split ratio between the bypass flow channel and the main flow channel, where the flow rate split ratio is determined through the flow rate calibration process. In addition, for any fluid medium, the volumetric heat capacity is the product of the density and the specific heat capacity. The volumetric heat capacity (ρ·C p )0 of the reference fluid in the calibration stage can be obtained by multiplying the density ρ0 of the reference fluid in the calibration stage and the specific heat capacity at constant pressure C p0 , and the volumetric heat capacity ρ·C p of the actual fluid can be obtained by multiplying the density ρ of the actual fluid and the specific heat capacity at constant pressure C p .

[0077] Optionally, in the embodiments of the present invention, Formula 2 can be obtained based on Formula 21 or Formula 22. Based on the measurement principle of the differential pressure type flow detection component, Formula 21 or Formula 22 can be obtained.

[0078] Formula 21:

[0079] Formula 22:

[0080] Among them, Q 主m is the mass flow rate of the fluid in the main flow channel; Q 主v is the volume flow rate of the fluid in the main flow channel; ΔP is the pressure difference detected by the differential pressure flow detection component; ρ1 is the density of the fluid medium (preferably, the average density under operating conditions); K6 is the instrument coefficient related to the geometric structure of the throttling component.

[0081] Specifically, for different throttling components, Formulas 21 and 22 have different expressions respectively. Taking the orifice plate structure as the throttling component as an example, there is the following quantitative relationship between the flow rate of the fluid and the pressure difference between the upstream and downstream of the throttling component (i.e., the pressure difference detected by the differential pressure flow detection component). In other words, Formulas 21 and 22 can be updated to Formulas 210 and 220 respectively.

[0082] Formula 210:

[0083] Formula 220:

[0084] Then, for Formulas 210 and 220,

[0085] Among them, Q 主m is the mass flow rate of the fluid in the main flow channel; Q 主v is the volume flow rate of the fluid in the main flow channel; C is the discharge coefficient; β is the diameter ratio of the throttling component; ε is the expansion coefficient; d is the orifice diameter; K2 is the instrument coefficient related to the geometric structure of the throttling component; ρ1 is the density of the fluid medium (preferably the average density under operating conditions); ΔP is the pressure difference detected by the differential pressure flow detection component.

[0086] Optionally, in the embodiment of the present invention, the throttling component can also be a Venturi structure.

[0087] When the fluid composition changes, the density of the fluid changes, and accurate measurement results cannot be obtained only through the differential pressure detected by the differential pressure flow detection component and temperature and pressure compensation correction.

[0088] According to the above analysis of the thermal flow measurement mode, when the fluid composition changes, due to the change of the physical properties of the fluid, the flow rate and pressure difference corresponding to the same temperature difference change, and among them, this change can be corrected by introducing physical property parameters.

[0089] Based on the above Formula 17, it can be obtained that when the reference fluid in the bypass flow channel during the calibration stage is flowing: Q 旁,0 = f(ΔT, (ΔP)0 / (ΔP)0, λ0 / λ0, (ρ·C p )0 / (ρ·C p )0).

[0090] Based on the above formula 17, when the fluid flowing in the bypass channel is an actual fluid other than the reference fluid in the calibration stage: Q 旁 = f(ΔT, (ΔP) / (ΔP)0, λ / λ0, (ρ·C p ) / (ρ·C p )0).

[0091] Based on the above formula 21 or formula 22, when the fluid flowing in the main channel is the reference fluid in the calibration stage: Q 主,0 = g((ΔP)0, ρ0).

[0092] Based on the above formula 21 or formula 22, when the fluid flowing in the main channel is an actual fluid other than the reference fluid in the calibration stage: Q 主 = g(ΔP, ρ)

[0093] According to the bypass flow sensor shunt principle, the main flow and the bypass flow are in a proportional relationship, then:

[0094] Thus, formula 23 is obtained: wherein, Q 旁 = f(ΔT, (ΔP) / (ΔP)0, λ / λ0, (ρ·C p ) / (ρ·C p )0); Q 旁,0 = f(ΔT, (ΔP)0 / (ΔP)0, λ0 / λ0, (ρ·C p )0 / (ρ·C p )0).

[0095] Based on formula 23 and formula 2 is obtained:

[0096] Based on formula 2 to determine the current differential pressure flow of the target fluid channel, the thermal flow signal detected by the thermal flow detection component and the differential pressure flow signal detected by the differential pressure flow detection component are coupled and processed, and the flow obtained by the differential pressure flow measurement method is corrected and calculated by using the temperature difference signal, the pressure difference signal and the physical property parameters to obtain the true flow information. If the current differential pressure flow is determined as the actual measured flow of the target fluid channel, the flow obtained by the differential pressure flow measurement method is corrected and calculated based on the temperature difference signal, and the factor sensitive to the component in the thermal flow measurement is introduced, so that the differential pressure flow measurement method further increases the consideration of the component and is more suitable for the application scenario where the medium component is unstable.

[0097] Thus, the change in the main flow channel due to the change in the component is corrected, and there is no need to perform a secondary correction on the change in the density ρ of the fluid medium.

[0098] Optionally, in the embodiments of the present invention, the thermal conductivity and specific heat capacity are detected by a physical property parameter detection component. Specifically, the physical property parameter detection component can detect the thermal conductivity and specific heat capacity by using a transient thermal pulse response method based on a thermal flow detection component. Optionally, the physical property parameter detection component can be a physical property sensor.

[0099] Optionally, in the embodiments of the present invention, determining the actual measured flow rate of the target fluid channel based on the current thermal flow rate and / or the current differential pressure flow rate and the flow rate measurement mode determination rule may include the following content.

[0100] Based on the current thermal flow rate and / or the current differential pressure flow rate, a comparison flow rate is determined. For example, the current thermal flow rate is determined as the comparison flow rate. Or, the current differential pressure flow rate is determined as the comparison flow rate. Or, by calculating the current thermal flow rate and the current differential pressure flow rate, a comparison flow rate is determined. For example, the average value of the current thermal flow rate and the current differential pressure flow rate is taken to determine the comparison flow rate. Or, other calculations can also be performed on the current thermal flow rate and the current differential pressure flow rate to determine the comparison flow rate. Based on the comparison flow rate and the flow rate measurement mode determination rule, the current thermal flow rate or the current differential pressure flow rate is determined as the actual measured flow rate of the target fluid channel to determine the flow rate of the target fluid channel.

[0101] Optionally, in the embodiments of the present invention, the flow rate measurement mode determination rule may include the following content. When the comparison flow rate is greater than or equal to the preset flow rate threshold, the current differential pressure flow rate is determined as the actual measured flow rate; and / or when the comparison flow rate is less than the preset flow rate threshold, the current thermal flow rate is determined as the actual measured flow rate. Optionally, in the embodiments of the present invention, the preset flow rate threshold can be set according to experience.

[0102] Optionally, in the embodiments of the present invention, the preset flow rate threshold is a flow rate value at which the flow rate change rate in the differential pressure flow rate measurement mode is equal to the flow rate change rate in the thermal flow rate measurement mode. Specifically, the preset flow rate threshold can be determined according to the following content.

[0103] Calculate the derivative function f'(ΔT) = dQ 旁 / d(ΔT) of the bypass flow rate in the thermal flow rate measurement mode and the derivative function g'(ΔP) = dQ 主 / d(ΔP) of the main flow rate in the differential pressure flow rate measurement mode. Make f'(ΔT) = g'(ΔP), and determine the appropriate critical flow rate switching value Q s Q s as the preset flow rate threshold. Wherein,

[0104] Optionally, in the embodiments of the present invention, the flow measurement mode determination rule may include the following. When the comparison flow rate is greater than or equal to the upper limit of the preset flow rate threshold range, the current differential pressure flow rate is determined as the actual measured flow rate; and / or when the comparison flow rate is less than the lower limit of the preset flow rate threshold range, the current thermal flow rate is determined as the actual measured flow rate. Optionally, in the embodiments of the present invention, the preset flow rate threshold range may be set according to experience.

[0105] Optionally, in the embodiments of the present invention, the preset flow rate threshold range may be determined according to the following. Based on the above method, the preset flow rate threshold Q is determined. s The preset flow rate threshold range is [Q s -δ, Q s +δ]. δ is a positive integer and can be set according to experience.

[0106] By comparing the comparison flow rate with the preset flow rate threshold or the upper and lower limits of the preset flow rate threshold range, the target fluid channel is divided into a small and medium flow rate mode or a large flow rate mode. When the comparison flow rate is less than the preset flow rate threshold or less than or equal to the lower limit of the preset flow rate threshold range, the target fluid channel is in the small and medium flow rate mode. At this time, the thermal flow measurement mode is adopted, and the current thermal flow rate is determined as the actual measured flow rate, which has a high sensitivity to small flows. When the comparison flow rate is greater than or equal to the preset flow rate threshold or greater than or equal to the upper limit of the preset flow rate threshold range, the target fluid channel is in the large flow rate mode. At this time, the differential pressure flow detection mode is adopted, and the current differential pressure flow rate is determined as the actual measured flow rate, which can ensure the velocity sensitivity and greatly improve the measurement range and measurement accuracy. The thermal flow measurement mode is more suitable for the small and medium flow rate mode and has a high sensitivity in the small and medium flow rate mode; the differential pressure flow measurement mode is more suitable for the large flow rate mode and has a high sensitivity in the large flow rate mode. In this way, by determining whether the target fluid channel is in the small and medium flow rate mode or the large flow rate mode based on the comparison flow rate and the preset flow rate threshold or the upper and lower limits of the preset flow rate threshold range, and selecting a suitable measurement method, the sensitivity of the flow measurement can be ensured and the measurement accuracy can be improved.

[0107] Optionally, in the embodiments of the present invention, to ensure the continuity of the flow rate switching, the flow rate measurement results in the two flow rate measurement modes are synchronously output, and the flow rate measurement mode is switched based on the preset flow rate threshold range [Q s -δ, Q s +δ].

[0108] The current output result Q (equivalent to the comparison flow rate described in the embodiments of the present invention) is the flow rate data obtained in the thermal flow measurement mode, and Q≥Q sWhen it is +δ, the output result is switched to the flow rate data in the differential pressure flow measurement mode, then:

[0109]

[0110] The current output result Q (equivalent to the comparison flow rate described in the embodiments of the present invention) is the flow rate data in the differential pressure flow measurement mode, and Q ≤ Q s When it is -δ, the output structure is switched to the flow rate data in the thermal flow measurement mode, then:

[0111]

[0112] Optionally, in the embodiments of the present invention, the flow rate of the target fluid passage under standard working conditions can be detected.

[0113] Optionally, the flow rate detection unit further includes a temperature detection component and a pressure detection component. The temperature detection component is used to detect the temperature in the bypass flow passage, and the pressure detection component is used to detect the pressure in the bypass flow passage. Before determining the flow rate of the target fluid passage based on the temperature difference, pressure difference, and physical property parameters of the fluid medium in the target fluid passage, the flow rate measurement method further includes the following. Obtain the temperature detected by the temperature detection component. Obtain the pressure detected by the pressure detection component. Among them, determining the flow rate of the target fluid passage is also based on the obtained temperature and the obtained pressure, and the determined flow rate of the target fluid passage is the flow rate under standard working conditions. Specifically, determining the flow rate of the target fluid passage based on the temperature difference, pressure difference, and physical property parameters of the fluid medium in the target fluid passage includes: determining the flow rate of the target fluid passage under standard working conditions based on the temperature, pressure, temperature difference, pressure difference, and physical property parameters of the fluid medium in the target fluid passage.

[0114] Optionally, for the thermal flow measurement mode, temperature and pressure correction are mainly used for the correction of specific heat capacity to obtain the specific volume flow rate under standard working conditions:

[0115]

[0116]

[0117] Among them, (ρ·C p ) std is the volume heat capacity under standard working conditions; (ρ·C p ) is the volume heat capacity under operating conditions; (ρ·C p )0 is the volume heat capacity of the reference fluid during the calibration stage (generally referring to air); P is the operating pressure, that is, the pressure detected by the pressure detection component; T is the operating temperature, that is, the temperature detected by the temperature detection component; P 标 is the working pressure under standard working conditions (101.325 kPa); T 标is the working temperature (20 °C) under standard conditions.

[0118] Optionally, for the differential pressure flow measurement mode, when the obtained flow rate is the volumetric flow rate under operating conditions, the volumetric flow rate under different operating states can be obtained by conversion using the detected temperature and pressure, such as standard conditions (101.325 kPa, 20 °C).

[0119]

[0120] where Q v,std is the volumetric flow rate under standard conditions; Q 差 is the volumetric flow rate under operating conditions; P is the operating pressure, i.e., the pressure detected by the pressure detection component; T is the operating temperature, i.e., the temperature detected by the temperature detection component; P 标 is the working pressure (101.325 kPa) under standard conditions; T 标 is the working temperature (20 °C) under standard conditions.

[0121] In a second aspect, an embodiment of the present invention further provides a flow measurement device. The flow measurement device includes: a memory and a processor. The memory is used to store a computer program. The processor is used to implement the flow measurement method described in the above embodiment by running the computer program stored in the memory.

[0122] In a third aspect, an embodiment of the present invention further provides a storage medium, on which a computer program is stored. When the computer program is run by a processor, the flow measurement method described in the above embodiment is implemented.

[0123] In a fourth aspect, an embodiment of the present invention further provides a flowmeter. The flowmeter includes a fluid channel, a flow detection unit, and a control module. The control module is used to execute the flow measurement method described in the above embodiment.

[0124] Figure 2 is a partial structural schematic diagram of a flowmeter provided by another embodiment of the present invention. The fluid channel includes a main flow channel 10 and a bypass flow channel 11. The main flow channel 10 includes a main flow channel pipe body. The bypass flow channel 11 includes a bypass flow channel pipe body. As Figure 3 , the bypass flow channel 11 is connected to the main flow channel 10 through a bypass connecting pipe 110 for pipeline connection.

[0125] The target fluid channel is connected to the main flow channel 10 through a pipeline. A throttling component 101 is disposed inside the main flow channel 10. The inlet of the bypass flow channel 11 is connected to the upstream pipeline of the throttling component 101, and the outlet of the bypass flow channel 11 is connected to the downstream pipeline of the throttling component 101. Specifically, as Figure 4As shown, the inlet of the bypass flow channel 11 is connected to the upstream of the throttling component 101 through a bypass connecting pipe 110, and the outlet of the bypass flow channel 11 is connected to the downstream of the throttling component 101 through the bypass connecting pipe 110.

[0126] Optionally, in the embodiment of the present invention, the relative pressure difference between the upstream inlet section and the downstream outlet pipe of the bypass connecting pipe 110 is small, that is, it can be ignored relative to the internal pressure difference of the bypass flow channel 11. The equivalent diameter d of the bypass connecting pipe 110 pipe is much larger than the equivalent diameter d of the bypass flow channel 11 channel . Preferably, d pipe ≥2d channel . Ensure the differential pressure consistency between the main flow channel 10 and the bypass flow channel 11.

[0127] The flow rate detection unit is located in the bypass flow channel 11. Optionally, the fluid in the bypass flow channel 11 is in a laminar flow state.

[0128] The flow rate detection unit includes a thermal flow detection component 20, a differential pressure flow detection component 21, and a physical property parameter detection component ( Figure 2 not shown in the figure). A temperature difference signal can be obtained based on the thermal flow detection component 20. A pressure difference signal before and after the differential pressure flow detection component 21 can be obtained based on the differential pressure flow detection component 21. The physical property parameter detection component can detect physical property parameters.

[0129] Optionally, in the embodiment of the present invention, the thermal flow detection component 20 and the differential pressure flow detection component 21 are connected in parallel. The inlet of the flow channel where the thermal flow detection component 20 is located is connected to the inlet of the flow channel where the differential pressure flow detection component 21 is located, and the outlet of the flow channel where the thermal flow detection component 20 is located is connected to the outlet of the flow channel where the differential pressure flow detection component 21 is located. In addition, in Figure 2 the figure, the solid arrows indicate the flow direction of the fluid medium, and the dashed arrows indicate the flow direction of the gas.

[0130] Optionally, in the embodiment of the present invention, the thermal flow detection component 20 can be a thermal flow sensor. Preferably, the thermal flow detection component 20 can be a MEMS thermal flow sensor.

[0131] Optionally, in the embodiment of the present invention, the differential pressure flow detection component 21 can be a differential pressure flow sensor. Preferably, the differential pressure flow detection component 21 can be a static differential pressure sensor (no air flow in the pressure detection cavity). Preferably, the differential pressure flow detection component 21 can be a thin film differential pressure sensor.

[0132] Optionally, in the embodiments of the present invention, a flow rectifying component 102 may also be disposed in the main flow channel 10. The number of the flow rectifying components 102 may be determined according to specific circumstances. However, in the case where the flow rectifying component 102 is provided, at least one flow rectifying component 102 is upstream of the upstream connection position of the bypass flow channel 11 and the main flow channel 10. As Figure 4 shown, two flow rectifying components 102 are included in the main flow channel 10. Among them, one flow rectifying component 102 is upstream of the upstream connection position of the bypass flow channel 11 and the main flow channel 10, and one flow rectifying component 102 is downstream of the downstream connection position of the bypass flow channel 11 and the main flow channel 10. Among them, in the embodiments of the present invention, the upstream and downstream may be determined according to the flow direction of the fluid medium.

[0133] The flow rectifying component 102 is a common flow regulator, and is used to adjust the fluid velocity uniformity of the fluid entering the main flow channel 10. Optionally, in the embodiments of the present invention, the flow rectifying component 102 may be a perforated plate, a grid plate, a screen, etc.

[0134] The throttling component 101 is used to generate a fluid pressure difference along the flow direction. Optionally, in the embodiments of the present invention, the throttling component 101 may be a standard orifice plate, a perforated plate, a laminar flow element, a grid plate, a screen, etc.

[0135] Optionally, in the embodiments of the present invention, regarding the geometric structure design of the bypass flow channel 11, a laminar flow pattern design is preferred. Through the laminar flow pattern design, the Reynolds number Re of the medium flow within the full flow measurement range is ≤ 2300. That is, wherein, u max is the maximum flow velocity allowed by the thermal flow detection component 20. D is the diameter of the bypass flow channel, and the equivalent diameter is taken when it is a non-circular pipe flow channel.

[0136] Thus, that is, the diameter of the bypass flow channel can be designed based on the physical properties of the fluid and the flow measurement range.

[0137] For a rectangular flow cross-section, that is, wherein, μ is the viscosity coefficient of the fluid medium, ρ is the density of the fluid medium, L is the height of the rectangular bypass flow cross-section, and W is the width of the rectangular bypass flow cross-section.

[0138] Optionally, when the thermal flow detection component 20 is a MEMS thermal flow sensor, the aspect ratio L / W of the flow interface ≥ 2. Combining the above content, the height L and width W of the flow cross-section of the bypass flow channel can be solved.

[0139] Figure 5 is a schematic cross-sectional structure diagram of a flow detection unit provided by another embodiment of the present invention.

[0140] AsFigure 5 As shown in the figure, the flow rate detection unit is located in the bypass channel. The flow rate detection unit includes a thermal flow rate detection component 20, a differential pressure flow rate detection component 21, a substrate 22, and a physical property parameter detection component 23. The substrate 22 includes a first gas through-hole 220 and a second gas through-hole 221. The substrate 22 divides the bypass channel into a microchannel 110 and a differential pressure detection chamber. The thermal flow rate detection component 20 and the differential pressure flow rate detection component 21 are integrated on both sides of the substrate 22. The physical property parameter detection component 23 and the differential pressure flow rate detection component 21 are integrated on the same side of the substrate 22. The differential pressure flow rate detection component 21 divides the differential pressure detection chamber into a first differential pressure detection chamber 1110 and a second differential pressure detection chamber 1111. The fluid medium in the microchannel 111 flows through the thermal flow rate detection component 20, and the gas in the microchannel 111 enters the first differential pressure detection chamber 1110 through the first gas through-hole 220, and the gas in the microchannel 111 enters the second differential pressure detection chamber 1111 through the second gas through-hole 221.

[0141] Optionally, in the embodiment of the present invention, the control module can be integrated on the substrate 22.

[0142] In the bypass channel, the upstream detection hole of the differential pressure flow rate detection component 21 is connected to the upstream of the microchannel 111 contacted by the thermal flow rate detection component 20, and the downstream detection hole of the differential pressure flow rate detection component 21 is connected to the downstream of the microchannel 111 contacted by the thermal flow rate detection component 20, so as to minimize the influence of the local pressure loss of the flow channel inlet section and outlet section on the linear pressure change law.

[0143] Optionally, in the embodiment of the present invention, the flow areas of the first gas through-hole 220 and the second gas through-hole 221 are not less than the equivalent diameter d of the bypass connecting pipe 110 pipe , so as to avoid the influence of the throttling of the first gas through-hole 220 and the second gas through-hole 221 on the measurement result of the differential pressure flow rate detection component 21. Preferably, the first differential pressure detection chamber 1110 and the second differential pressure detection chamber 1111 are symmetrically designed with respect to the differential pressure flow rate detection component 21.

[0144] Optionally, in the embodiment of the present invention, as Figure 5 described, the flow rate detection unit may further include a temperature detection component 24 and a pressure detection component 25. The temperature detection component 24 and the pressure detection component 25 are integrated on the substrate 22. The temperature detection component 24 is used to detect the temperature in the bypass channel. Specifically, the temperature detection component 24 detects the temperature in the first differential pressure detection chamber 1110. Optionally, the temperature detection component 24 is a temperature sensor. The pressure detection component 25 is used to detect the pressure in the bypass channel. Specifically, the pressure detection component 25 detects the pressure in the first differential pressure detection chamber 1110. Optionally, the pressure detection component 24 is a pressure sensor.

[0145] Figure 6 It is a schematic cross-sectional structure diagram of a flow detection unit provided by another embodiment of the present invention. Figure 6 The shown flow detection unit and Figure 5 The difference between the shown flow detection units is only that, Figure 6 The shown flow detection unit further includes a first bypass cut-off micro-valve 26 and a first bypass cut-off micro-valve 27. The first bypass cut-off micro-valve 26 and the first bypass cut-off micro-valve 27 are located downstream of the thermal flow detection component 20 and on both sides of the second gas through-hole 221. The first bypass cut-off micro-valve 26 and the first bypass cut-off micro-valve 27 being located downstream of the thermal flow detection component 20 can avoid the influence of flow field interference caused by the mismatch between the micro-valve channel and the bypass flow channel on flow measurement.

[0146] The open states of the first bypass cut-off micro-valve 26 and the first bypass cut-off micro-valve 27 are used to realize the enabled state of the bypass flow channel structure and the zero-point calibration of the thermal flow detection component 20 and the differential pressure flow detection component 21.

[0147] When the first bypass cut-off micro-valve 26 is closed and the first bypass cut-off micro-valve 27 is open, there is no medium flow in the bypass flow channel, which can be used for the zero-point calibration of components such as the thermal flow detection component 20 and the physical property parameter detection component 23 to eliminate the influence of changes in operating conditions or fluid medium differences on the zero point. Similarly, at this time, the flowmeter can also be switched to the differential pressure flow detection mode without bypass flow channel circulation, without considering the shunt flow of the bypass flow channel, that is

[0148]

[0149] This situation can be used to solve application scenarios such as partial or complete blockage of the bypass flow channel during long-term operation, and the measurement failure of the thermal flow detection component due to pollution or failure, etc., and can solve the flow measurement problem during the period when the thermal flow detection component cannot work properly.

[0150] When the first bypass cut-off micro-valve 26 is open and the first bypass cut-off micro-valve 27 is closed, there is no medium flow in the bypass flow channel, and the upstream and downstream communication holes (the first gas through-hole 220 and the second gas through-hole 221) of the differential pressure detection cavity and the micro-channel 111 are in a short-circuit state. At this time, it can be used for the zero-point calibration of the differential pressure flow detection component 21.

[0151] Optionally, in the embodiments of the present invention, the first bypass cut-off micro-valve 26 and the first bypass cut-off micro-valve 27 can also be located upstream of the thermal flow detection component 20 and on both sides of the first gas through-hole 220. When the first bypass cut-off micro-valve 26 and the first bypass cut-off micro-valve 27 are located upstream of the thermal flow detection component 20, the switch states are just opposite to those when the first bypass cut-off micro-valve 26 and the first bypass cut-off micro-valve 27 are located downstream of the thermal flow detection component 20.

[0152] Optionally, in the embodiments of the present invention, the flow detection unit further includes: the flow measurement module described in the above embodiments, integrated on the substrate.

[0153] Figure 7 It is a partial composition schematic diagram of a flowmeter provided by another embodiment of the present invention. As Figure 7 shown, the flowmeter includes a differential pressure flow detection component, a thermal flow sensor, etc. Further, the flowmeter may include an integrated chip module composed of a differential pressure flow detection component, a thermal flow sensor, etc. The integrated chip module includes a sensor integration unit, a MEMS microvalve system, a conditioning and amplification module, an A / D conversion module, a digital processing and communication module, etc. The sensor integration unit includes a thermal flow sensor, a physical property sensor, a temperature sensor, a pressure sensor, and a differential pressure flow detection component. The MEMS microvalve system includes the first bypass cut-off microvalve and the first bypass cut-off microvalve described in the above embodiments. The conditioning and amplification module amplifies the signal received from the sensor integration unit and then transmits it to the A / D conversion module. The A / D conversion module converts the received signal into a digital signal. The digital processing and communication module receives the signal transmitted by the A / D conversion module, processes it based on the flow measurement method described in the above embodiments to obtain the flow rate, and can transmit the obtained flow rate.

[0154] In a fifth aspect, an embodiment of the present invention further provides a computer program product, which includes computer program instructions. When the computer program instructions are run by a processor, the processor is caused to execute the steps of the flow measurement method described in the above embodiments.

[0155] The computer program product can be written in any combination of one or more programming languages for the program code to execute the operations of the embodiments of this specification. The programming languages include object-oriented programming languages such as Java, C++, etc., and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, executed as an independent software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0156] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the embodiments provided in this specification can include non-volatile and / or volatile memories. Non-volatile memories can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memories can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0157] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0158] The above embodiments only represent several implementation manners of this specification. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of this specification, several modifications and improvements can still be made, and these all belong to the protection scope of this specification. Therefore, the protection scope of the patent of this specification should be subject to the appended claims.

Claims

1. A flow measurement method, characterized in that, For measuring the flow rate in a target fluid channel, the flow rate measurement method includes: Obtaining the temperature difference detected by a thermal flow detection component in a flowmeter. The flowmeter includes a fluid channel and a flow detection unit. The fluid channel includes a main flow channel and a bypass flow channel. The target fluid channel is connected to the main flow channel through a pipeline. A throttling component is disposed in the main flow channel. The inlet of the bypass flow channel is connected to the upstream pipeline of the throttling component, and the outlet of the bypass flow channel is connected to the downstream pipeline of the throttling component. The flow detection unit is located in the bypass flow channel. The flow detection unit includes the thermal flow detection component, a differential pressure flow detection component, and a substrate. The substrate includes a first gas through-hole and a second gas through-hole. The substrate divides the bypass flow channel into a micro-channel and a differential pressure detection chamber. The thermal flow detection component and the differential pressure flow detection component are integrated on both sides of the substrate; Obtaining the pressure difference detected by the differential pressure flow detection component. The pressure difference detected by the differential pressure flow detection component is the pressure drop generated by the fluid flowing through the bypass flow channel where the thermal flow detection component is placed; and Based on the temperature difference, the pressure difference, and the physical property parameters of the fluid medium in the target fluid channel, determining the flow rate of the target fluid channel; Wherein, the determining the flow rate of the target fluid channel based on the temperature difference, the pressure difference, and the physical property parameters of the fluid medium in the target fluid channel includes: Determining the current thermal flow rate and the current differential pressure flow rate of the target fluid channel. The current thermal flow rate is determined based on a thermal flow measurement mode in combination with the temperature difference, the pressure difference, and the physical property parameters of the fluid medium in the target fluid channel. The current differential pressure flow rate is determined based on a differential pressure flow measurement mode in combination with the temperature difference, the pressure difference, and the physical property parameters of the fluid medium in the target fluid channel; Based on the current thermal flow rate and / or the current differential pressure flow rate and the flow measurement mode determination rule, determining the current thermal flow rate or the current differential pressure flow rate as the actual measured flow rate of the target fluid channel to determine the flow rate of the target fluid channel.

2. The flow measurement method according to claim 1, characterized in that, The flow detection unit further includes a temperature detection component and a pressure detection component. The temperature detection component is used to detect the temperature in the bypass flow channel, and the pressure detection component is used to detect the pressure in the bypass flow channel; Wherein, before the determining the flow rate of the target fluid channel based on the temperature difference, the pressure difference, and the physical property parameters of the fluid medium in the target fluid channel, the flow rate measurement method further includes: Obtaining the temperature detected by the temperature detection component; and Obtaining the pressure detected by the pressure detection component; Wherein, the determining the flow rate of the target fluid channel based on the temperature difference, the pressure difference, and the physical property parameters of the fluid medium in the target fluid channel includes: Based on the temperature, the pressure, the temperature difference, the pressure difference, and the physical property parameters of the fluid medium in the target fluid channel, determining the flow rate of the target fluid channel under standard working conditions.

3. The flow measurement method according to claim 1, characterized in that, Based on the current thermal flow rate and / or the current differential pressure flow rate and the flow measurement mode determination rule, determining the current thermal flow rate or the current differential pressure flow rate as the actual measured flow rate of the target fluid channel includes: Based on the current thermal flow rate and / or the current differential pressure flow rate, determining a comparison flow rate; Based on the comparison flow rate and the flow measurement mode determination rule, determining the current thermal flow rate or the current differential pressure flow rate as the actual measured flow rate of the target fluid channel to determine the flow rate of the target fluid channel.

4. The flow measurement method according to claim 3, characterized in that, The flow measurement mode determination rule includes: Determining the current differential pressure flow rate as the actual measured flow rate when any of the following is satisfied: the comparison flow rate is greater than or equal to a preset flow rate threshold, the comparison flow rate is greater than or equal to the upper limit of a preset flow rate threshold range; and / or Determining the current thermal flow rate as the actual measured flow rate when any of the following is satisfied: the comparison flow rate is less than the preset flow rate threshold, the comparison flow rate is less than or equal to the lower limit of the preset flow rate threshold range.

5. The flow measurement method according to claim 1, characterized in that, The physical property parameters include thermal conductivity, density, and specific heat capacity.

6. A flow measurement device, characterized in that, For measuring the flow rate in a target fluid channel, the flow measurement device includes: A memory; A processor, the memory is used to store a computer program, and the processor is used to implement the flow measurement method according to any one of claims 1-5 by running the computer program stored in the memory.

7. A storage medium, characterized in that, A computer program is stored on the storage medium, and when the computer program is run by a processor, it implements the flow measurement method according to any one of claims 1-5.

8. A flowmeter, characterized in that, The flowmeter includes: A fluid channel, the fluid channel includes a main flow channel and a bypass flow channel, the target fluid channel is connected to the main flow channel through a pipeline, a throttling component is built in the main flow channel, the inlet of the bypass flow channel is connected to the upstream pipeline of the throttling component, and the outlet of the bypass flow channel is connected to the downstream pipeline of the throttling component; and A flow detection unit, located in the bypass flow channel, the flow detection unit includes a thermal flow detection component, a differential pressure flow detection component, a physical property parameter detection component, and a substrate, the substrate includes a first gas through-hole and a second gas through-hole, the substrate divides the bypass flow channel into a micro flow channel and a differential pressure detection cavity, and the thermal flow detection component and the differential pressure flow detection component are integrated on both sides of the substrate; A control module for executing the flow measurement method according to any one of claims 1-5.

9. The flowmeter according to claim 8, characterized in that, The physical property parameter detection component and the differential pressure flow detection component are integrated on the same side of the substrate, the differential pressure flow detection component divides the differential pressure detection cavity into a first differential pressure detection cavity and a second differential pressure detection cavity, the fluid medium in the micro flow channel flows through the thermal flow detection component, the gas in the micro flow channel enters the first differential pressure detection cavity through the first gas through-hole, and the gas in the micro flow channel enters the second differential pressure detection cavity through the second gas through-hole.

10. The flowmeter according to claim 8, characterized in that, The flow detection unit further includes: a temperature detection component for detecting the temperature in the bypass flow channel; and a pressure detection component for detecting the pressure in the bypass flow channel.

11. The flowmeter according to claim 8, wherein The main flow channel further internally includes at least one flow rectifying component, and at least one of the at least one flow rectifying components is located upstream of the upstream connection position between the bypass flow channel and the main flow channel.

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