Multi-component gas flow compensation device and compensation method

Abstract

The present invention discloses a multi-component gas flow compensation device, comprising: a gas main channel, a group of branch channels, and an outlet channel, wherein the branch channel is provided on one side of the gas main channel, and the outlet channel is provided at one end of the branch channel away from the gas main channel. A first sensor and a second sensor are provided in the gas main channel and the branch channel, respectively, and the flow velocities in the gas main channel and the branch channel are different and present a nonlinear relationship. The present invention provides multiple flow channels and arranges at least two thermal flow sensors in the flow channels to couple multiple flow signals, eliminating the influence of medium physical properties on the flow signal output, and obtaining a quantitative relationship between the gas flow rate and the medium-independent sensor output. The flow meter does not need to integrate component or physical property detection sensors, nor does it need to obtain gas conversion coefficients through real gas calibration, greatly simplifying the calibration and detection process and improving the accuracy and adaptability of thermal gas mass flow meters in the field of multi-component gas measurement.

Description

Technical Field

[0001] The present invention belongs to the technical field of flow meters, and in particular relates to a multi-component gas flow compensation device and a compensation method. Background Art

[0002] Thermal gas mass flowmeters are based on the principles of fluid heat transfer, specifically, a technology that uses the heat exchange relationship between the fluid and the sensor's heat source to measure gas flow. According to this fundamental principle, the metering output of a thermal gas mass flowmeter depends simultaneously on the gas mass flow rate, thermodynamic properties, and instrument structural parameters. Changes in factors such as the composition, temperature, or pressure of the measured gas can cause changes in gas properties, which in turn affect the metering output of the thermal gas mass flowmeter and cause significant measurement errors. Therefore, to improve the accuracy and environmental suitability of MEMS thermal metering instruments, real-time compensation for deviations caused by fluctuations in these variables is necessary.

[0003] Online component identification and correction for thermal flowmeters is a research hotspot in the MEMS flow metering industry. Existing technologies primarily utilize integrated physical property sensors to detect the medium's thermal properties and convert them into gas conversion coefficients for online flow correction. This method places high demands on the physical property sensor's detection accuracy and environmental suitability, requiring simultaneous detection of multiple thermal property parameters and flow rates. Complex multi-component gases and actual detection environments present additional uncertainties. Failure to ensure accurate physical property detection can significantly impact the measurement accuracy of thermal gas flowmeters.

[0004] Therefore, it is necessary to propose an online real-time correction method for thermal gas mass flowmeters that does not rely on online physical property detection to improve the accuracy and adaptability of thermal gas mass flowmeters in the field of multi-component mixed gas measurement. Summary of the Invention

[0005] Purpose of the invention: In order to overcome the above shortcomings, the purpose of the present invention is to provide a multi-component gas flow compensation device with a simple structure and reasonable design. It is easy to arrange two (or more) thermal flow sensors in the flow channel and couple multiple flow signals to eliminate the influence of the physical properties of the medium on the flow signal output. The quantitative relationship between the gas flow and the medium-independent sensor output is obtained, which solves the problem that gas component detection lacks real-time performance and is limited to specific gas types, and improves the accuracy and adaptability of thermal gas mass flowmeters in the field of multi-component gas measurement.

[0006] Technical Solution: To achieve the above-mentioned objectives, the present invention provides a multi-component gas flow compensation device, comprising: a gas main channel, a group of branch channels, and an outlet channel, wherein the branch channel is provided on one side of the gas main channel, and the outlet channel is provided at an end of the branch channel away from the gas main channel, wherein a first sensor and a second sensor are provided in the gas main channel and the branch channel, respectively, and the flow velocities in the main channel and the branch channel are different and have a nonlinear relationship. The multi-component gas flow compensation device of the present invention has a simple structure, a reasonable design, and is suitable for production. By providing multiple flow channels, arranging two (or more) thermal flow sensors in the flow channels, and coupling processing the multiple flow signals, the influence of the medium physical properties on the flow signal output is eliminated, and a quantitative relationship between the gas flow rate and the medium-independent sensor output is obtained. Since the improved flow meter does not need to integrate component or physical property detection sensors, nor does it need to obtain gas conversion coefficients through actual gas calibration, the calibration and detection process is greatly simplified, and the problem of gas component detection lacking real-time performance and being limited to specific gas types is effectively solved, thereby effectively improving the accuracy and adaptability of thermal gas mass flow meters in the field of multi-component gas measurement.

[0007] The branch flow channel includes a first flow channel and a second flow channel, and both the first flow channel and the second flow channel are provided with a flow blocker. The provision of the flow blocker can effectively ensure a nonlinear relationship between the main gas flow channel and the branch flow channel.

[0008] Furthermore, a second sensor is provided in the first flow channel.

[0009] Furthermore, a second sensor is provided in the second flow channel.

[0010] Furthermore, a second sensor is provided in each of the first flow channel and the second flow channel.

[0011] Preferably, the first sensor and the second sensor are both MEMS calorimetric flow sensors.

[0012] Preferably, the first sensor is a MEMS calorimetric flow sensor, and the second sensor is a MEMS anemometer sensor or a MEMS time-of-flight sensor.

[0013] The calibration process of the multi-component gas flow compensation device described in the present invention is as follows:

[0014] 1): Flow detection of reference gas flow sensors in each flow channel;

[0015] 2) By coupling each flow sensor, the influence of medium physical properties is eliminated, the flow combination output item is obtained and a quantitative relationship between it and the reference gas medium flow is established;

[0016] 3): Change the temperature and pressure of the measured gas to verify the physical property independence of the calibration curve. That is, if the query value is consistent with the true value, the calibration process ends. If the query value is different from the true value, return to 2) to adjust the fitting relationship.

[0017] The compensation method of the multi-component gas flow compensation device described in the present invention is specifically calibrated as follows:

[0018] At least two thermal flow sensors of the same MEMS calorimetric flow sensor type are provided in the flow channel. The flow channel design allows the flow velocities of each flow channel to be different, and the flow velocity of at least one flow channel varies nonlinearly with the flow velocity u of the main flow channel, i.e., u1=u1(u), u2=u2(u), ..., un=un(u). The branch flow channel may be provided with a resistance element to adjust the nonlinear relationship between the branch flow velocity un and the main flow channel flow velocity u.

[0019] S1: Using air or nitrogen as a reference gas, measure the voltage outputs of the branch flow sensors at different main flow velocity u: U(△T(u),α), U1(△T(u1),α), U2(△T(u2),α), ..., Un(△T(un),α). The quantitative relationship between the main flow velocity u and the main flow sensor voltage output U is obtained through data fitting and other methods, i.e., the initial calibration curve.

[0020] The quantitative relationship is as follows: u~U(△T(u),α);

[0021] Determine the flow rate of each flow channel according to the initial calibration curves u~U(△T(u),α) and the voltage output signals of each sensor; the voltage output signals of each sensor include U1(△T(u1),α), U2(△T(u2),α), ..., Un(△T(un,α));

[0022] The method for determining the flow rate of each flow channel is to bring the voltage output signal of each sensor into the initial calibration curve fitting formula or query the initial calibration relationship u~U(△T(u),α) mapping table; the flow rate of each flow channel includes the first flow channel flow rate u1, the second flow channel flow rate u2, ..., the flow channel n flow rate un;

[0023] According to the flow velocity u of each flow channel at different flow rates and the sensor voltage output signal U, the initial calibration curves u1~U1(△T(u1),α), u2~U2(△T(u2),α),……,un~Un(△T(un),α) of each flow channel are obtained;

[0024] The first sensor and the second sensor are MEMS calorimetric flow sensors with completely identical sensor structures and working principles. The initial calibration curves or quantitative relationships of the sensors have a unified or similar mathematical expression, including the following mathematical forms:

[0025]

[0026]

[0027] …

[0028]

[0029] Wherein, u, u1, u2 and un are respectively the flow rates of the measured gas corresponding to different flow channels; α is the physical property parameter of the measured gas, which includes but is not limited to a single physical property such as thermal conductivity, volume heat capacity and thermal diffusivity, or a mathematical combination of any two or more physical properties; ΔT is the raw signal data of the flow sensor. For a MEMS calorimetric flow sensor, it is mainly the temperature difference between the upstream and downstream temperature measuring elements of the heating element; c1 and c2 are instrument parameters related to the sensor geometry and flow channel structure; U is the voltage output signal of the flow sensor raw signal ΔT converted by the measuring bridge;

[0030] The output of each sensor is coupled to obtain the combined output of each sensor f(U(ΔT),U(ΔT n )), and establish the quantitative relationship between gas flow and sensor combination output u~f(U(ΔT),U(ΔT n )); The coupling processing of the outputs of each flow sensor includes, but is not limited to, performing mathematical operations such as addition, subtraction, multiplication, division, and power functions on the output signals of each sensor to eliminate the physical parameter term α; the coupling processing method is to perform mathematical conversion processing on the calibration relationship of each sensor based on similarity theory, eliminate the physical parameter term α in the initial calibration relationship, and obtain a combined output term based on the initial output signal of each sensor;

[0031] The combined output of each sensor includes the following forms:

[0032]

[0033] or

[0034] f(U(ΔT), U(ΔT n ))=c1*ΔT n1 +c2*ΔT n n2 +c3

[0035] The output of the sensor combination after coupling processing is only related to the original signal ΔT of each flow sensor, that is, it is a function of the initial voltage output signal U of each flow sensor;

[0036] Among them, ΔT, ΔT nis the temperature difference signal output of the upstream and downstream temperature measuring elements of the flow sensor for the first flow channel and any other flow channel n, c1, c2, c3, n1, n2, etc. are instrument coefficients related to the sensor geometry and flow channel structure;

[0037] The quantitative relationship between u and the output signals of the sensors of each flow channel including the main gas flow channel is as follows:

[0038] u~f(U, U1, U2,…, Un)=f(△T(u), △T(u1), △T(u2),…, △T(un))

[0039] The output signals of the flow channel sensors at least include the flow sensor outputs of any two or more flow channels of the main flow channel and the branch flow channel;

[0040] S3: Change the temperature or pressure of the reference gas to change the density, volume heat capacity, thermal conductivity and other single physical properties of the measured gas or any mathematical combination of two or more physical properties; obtain the medium flow rate based on the calibration curve query and verify the consistency with the actual flow rate output by the calibration device; if the query value is consistent with the actual value, that is The calibration process ends; if the query value is inconsistent with the true value, Then return to step 2 to adjust the fitting relationship;

[0041] Among them, C is the consistency verification deviation control threshold, which is set manually according to the deviation requirements.

[0042] The calibration process of the multi-component gas flow compensation device described in the present invention, the detection process of the first sensor and the second sensor is as follows:

[0043] 1): Each flow channel sensor performs flow detection, that is, the first sensor and the second sensor in the gas main flow channel and the branch flow channel obtain the output signals U, U1, U2, ..., Un of the sensors corresponding to different gas flow rates passing through the medium;

[0044] 2): Calculation of sensor flow combination output items: According to the sensor coupling processing method obtained in the calibration stage, calculate the sensor combination output items f(U, U1, U2, ..., Un);

[0045] 3) Flow measurement: Obtain the sensor combination output item f(U, U1, U2, ..., Un) according to step 2, check the flow sensor calibration curve or data mapping table, u ~ f(U, U1, U2, ..., Un), and obtain the actual gas flow rate; the gas flow rate includes volume flow u, standard volume flow V and mass flow m;

[0046] Furthermore, in the above detection process, when the measured medium is a single-component gas or a multi-component gas with relatively stable components, the output of each sensor can be directly used as a separate metering module.

[0047] It can be seen from the above technical solution that the present invention has the following beneficial effects:

[0048] 1. The multi-component gas flow compensation device described in the present invention has a simple structure and a reasonable design. It is used for production. By setting multiple flow channels and arranging two (or more) thermal flow sensors in the flow channels, and coupling processing multiple flow signals, the influence of the medium physical properties on the flow signal output is eliminated, and a quantitative relationship between the gas flow and the medium-independent sensor output is obtained. Since the improved flow meter does not need to integrate component or physical property detection sensors, nor does it need to obtain the gas conversion coefficient through real gas calibration, the calibration and detection process is greatly simplified, and the problem that gas component detection lacks real-time performance and is limited to specific gas types is well solved, effectively improving the accuracy and adaptability of thermal gas mass flow meters in the field of multi-component gas measurement.

[0049] 2. The present invention couples multiple flow signals to eliminate physical property items in the calibration relationship. There is no need to set up physical property detection sensors and actual gas calibration. It can be used for any gas measurement after a one-time calibration with common media such as air or nitrogen, which greatly simplifies the instrument calibration process and reduces the engineering implementation cost of MEMS thermal gas flow meters.

[0050] 3. The branching channel of the present invention includes a first channel and a second channel, each of which is provided with a flow blocker. The provision of the flow blocker controls the pressure loss along the channel by varying the flow state (laminar flow vs. turbulent flow) of the channel, thereby varying the fluid flow rate or velocity in each channel, effectively maintaining a nonlinear relationship between the main gas channel and the branching channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of the structure of the multi-component gas flow compensation device of the present invention;

[0052] Figure 2 Schematic diagram of the calibration process of the MEMS thermal gas mass flowmeter in the present invention;

[0053] Figure 3 Schematic diagram of the detection process of the MEMS thermal gas mass flowmeter in the present invention. DETAILED DESCRIPTION

[0054] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0055] Example

[0056] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0057] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0058] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise explicitly specified.

[0059] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0060] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0061] Example 1

[0062] As shown in the figure, a multi-component gas flow compensation device includes: a gas main channel 1, a group of branch channels 2 and an outlet channel 3. The branch channel 2 is arranged on one side of the gas main channel 1, and the outlet channel 3 is arranged at the end of the branch channel 2 away from the gas main channel 1. A first sensor 4 and a second sensor 5 are respectively provided in the gas main channel 1 and the branch channel 2, and the flow velocities in the main channel 1 and the branch channel 2 are different and have a nonlinear relationship.

[0063] In this embodiment, the branch flow channel 2 includes a first flow channel 21 and a second flow channel 22 . A flow blocking member 6 is disposed in each of the first flow channel 21 and the second flow channel 22 .

[0064] In this embodiment, a second sensor 5 is provided in the first flow channel 21 .

[0065] In this embodiment, the first sensor 4 and the second sensor 5 are both MEMS calorimetric flow sensors.

[0066] Example 2

[0067] As shown in the figure, a multi-component gas flow compensation device includes: a gas main channel 1, a group of branch channels 2 and an outlet channel 3. The branch channel 2 is arranged on one side of the gas main channel 1, and the outlet channel 3 is arranged at the end of the branch channel 2 away from the gas main channel 1. A first sensor 4 and a second sensor 5 are respectively provided in the gas main channel 1 and the branch channel 2, and the flow velocities in the main channel 1 and the branch channel 2 are different and have a nonlinear relationship.

[0068] In this embodiment, the branch flow channel 2 includes a first flow channel 21 and a second flow channel 22 . A flow blocking member 6 is disposed in each of the first flow channel 21 and the second flow channel 22 .

[0069] In this embodiment, a second sensor 5 is provided in the second flow channel 22 .

[0070] In this embodiment, the first sensor 4 is a MEMS calorimetric flow sensor, and the second sensor 5 is a MEMS anemometer sensor or a MEMS time-of-flight sensor.

[0071] Example 3

[0072] As shown in the figure, a multi-component gas flow compensation device includes: a gas main channel 1, a group of branch channels 2 and an outlet channel 3. The branch channel 2 is arranged on one side of the gas main channel 1, and the outlet channel 3 is arranged at the end of the branch channel 2 away from the gas main channel 1. A first sensor 4 and a second sensor 5 are respectively provided in the gas main channel 1 and the branch channel 2, and the flow velocities in the main channel 1 and the branch channel 2 are different and have a nonlinear relationship.

[0073] In this embodiment, the flow divider includes a first flow channel 21 and a second flow channel 22. A flow block 6 is provided in each of the first flow channel 21 and the second flow channel 22. The flow block 6 is a fluid baffle, a flow block, or a bellows. The flow block 6 is a rigid structure or an elastic structure that changes shape according to the force applied.

[0074] In this embodiment, a second sensor 5 is disposed in both the first flow channel 21 and the second flow channel 22 .

[0075] In this embodiment, the first sensor 4 is a MEMS calorimetric flow sensor, and the second sensor 5 is a MEMS anemometer sensor or a MEMS time-of-flight sensor.

[0076] Example 4

[0077] The structure of the multi-component gas flow compensation device in this embodiment is the same as that in embodiment 1, embodiment 2 or embodiment 3.

[0078] The compensation method of the multi-component gas flow compensation device described in this embodiment has a specific calibration process as follows:

[0079] 1): Flow detection of reference gas flow sensors in each flow channel;

[0080] 2) By coupling each flow sensor, the influence of medium physical properties is eliminated, the flow combination output item is obtained and a quantitative relationship between it and the reference gas medium flow is established;

[0081] 3): Change the temperature and pressure of the measured gas to verify the physical property independence of the calibration curve. That is, if the query value is consistent with the true value, the calibration process ends. If the query value is different from the true value, return to 2) to adjust the fitting relationship.

[0082] The calibration process of the multi-component gas flow compensation device described in this embodiment is to set two (or more) thermal flow sensors in the flow channel, using the same MEMS calorimetric flow sensor type. The flow channel is designed so that the flow velocities (u, u1, u2, ..., un) of each flow channel are different, and the flow velocity change of at least one flow channel is nonlinear with the flow velocity u of the main flow channel, that is, u1 = u1(u), u2 = u2(u), ..., un = un(u); the branch flow channel can be provided with a resistance element to adjust the nonlinear relationship between the branch flow velocity un and the main flow channel flow velocity u;

[0083] The thermal flow sensor includes but is not limited to a MEMS calorimetric flow sensor, and may also be a MEMS hot wire anemometer sensor or a time-of-flight sensor. Preferably, the structural type and working principle of each sensor are consistent; optionally, the structural type and working principle of each sensor are inconsistent, including but not limited to the following situations: the main channel sensor is a MEMS calorimetric flow sensor, and the branch channel is a MEMS hot wire anemometer sensor or a time-of-flight sensor; or, the main channel and branch channel sensors use the same MEMS calorimetric flow sensor, the former's working mode adopts a constant temperature difference (CTD) mode, and the primary output signal of the flow sensor is the temperature difference between the upstream and downstream of the heating element, the latter's working mode adopts a constant power (CP) mode, or the latter also adopts a constant temperature difference (CTD) working mode, but the sensor's primary output signal is the power of the heating element;

[0084] The flow rates of the various flow channels are not the same, which mainly refers to the fact that the flow channels have different fluid flow rates, that is, u1≠u2, and also includes the fact that the flow rate of a branch flow channel is zero or close to the critical rate;

[0085] The establishment of the nonlinear relationship can be achieved through the fluid flow pattern (laminar or turbulent) or the design of the resistance element structure. Among them, the establishment of the nonlinear relationship between different flow channels through the fluid flow pattern mainly refers to relying on the difference in the flow state of the flow channel (laminar and turbulent) to control the pressure loss along the flow channel, thereby changing the fluid flow rate or speed of each flow channel. The establishment of the nonlinear relationship between different flow channels through the design of the resistance element structure includes the following methods: setting resistance elements in the flow channel, changing the flow channel structure or wall roughness, such as fluid baffles or flow blocks, bellows, etc.; the resistance element is a rigid structure, and can also be an elastic structure that changes its deformation according to the force conditions;

[0086] The thermal flow sensor includes but is not limited to a MEMS calorimetric flow sensor, and may also be a MEMS hot wire anemometer sensor or a time-of-flight sensor. Preferably, the structural type and working principle of each sensor are consistent; optionally, the structural type and working principle of each sensor are inconsistent, including but not limited to the following situations: the main channel sensor is a MEMS calorimetric flow sensor, and the branch channel is a MEMS hot wire anemometer sensor or a time-of-flight sensor; or, the main channel and branch channel sensors use the same MEMS calorimetric flow sensor, the former's working mode adopts a constant temperature difference (CTD) mode, and the primary output signal of the flow sensor is the temperature difference between the upstream and downstream of the heating element, the latter's working mode adopts a constant power (CP) mode, or the latter also adopts a constant temperature difference (CTD) working mode, but the sensor's primary output signal is the power of the heating element;

[0087] The flow rates of the various flow channels are not the same, which mainly refers to the fact that the flow channels have different fluid flow rates, that is, u1≠u2, and also includes the fact that the flow rate of a branch flow channel is zero or close to the critical rate;

[0088] The establishment of the nonlinear relationship can be achieved through the fluid flow pattern (laminar or turbulent) or the design of the resistance element structure. Among them, the establishment of the nonlinear relationship between different flow channels through the fluid flow pattern mainly refers to relying on the difference in the flow state of the flow channel (laminar and turbulent) to control the pressure loss along the flow channel, thereby changing the fluid flow rate or speed of each flow channel. The establishment of the nonlinear relationship between different flow channels through the design of the resistance element structure includes the following methods: setting resistance elements in the flow channel, changing the flow channel structure or wall roughness, such as fluid baffles or flow blocks, bellows, etc.; the resistance element is a rigid structure, and can also be an elastic structure that changes its deformation according to the force conditions;

[0089] The specific calibration method is as follows:

[0090] S1: Using air or nitrogen as a reference gas, measure the voltage outputs of the branch flow sensors at different main flow velocity u: U(△T(u),α), U1(△T(u1),α), U2(△T(u2),α), ..., Un(△T(un),α). The quantitative relationship between the main flow velocity u and the main flow sensor voltage output U is obtained through data fitting and other methods, i.e., the initial calibration curve.

[0091] The quantitative relationship is as follows: u~U(△T(u),α);

[0092] Determine the flow rate of each flow channel according to the initial calibration curves u~U(△T(u),α) and the voltage output signals of each sensor; the voltage output signals of each sensor include U1(△T(u1),α), U2(△T(u2),α), ..., Un(△T(un,α));

[0093] The method for determining the flow rate of each flow channel is to bring the voltage output signal of each sensor into the initial calibration curve fitting formula or query the initial calibration relationship u~U(△T(u),α) mapping table; the flow rate of each flow channel includes the first flow channel flow rate u1, the second flow channel flow rate u2, ..., the flow channel n flow rate un;

[0094] According to the flow velocity u of each flow channel at different flow rates and the sensor voltage output signal U, the initial calibration curves u1~U1(△T(u1),α), u2~U2(△T(u2),α),……,un~Un(△T(un),α) of each flow channel are obtained;

[0095] The first sensor (4) and the second sensor (5) adopt MEMS calorimetric flow sensors with completely identical sensor structures and working principles, and the initial calibration curves or quantitative relationships of the sensors have a unified mathematical expression form, including the following mathematical form:

[0096]

[0097]

[0098] …

[0099]

[0100] Wherein, u, u1, u2 and un are respectively the flow rates of the measured gas corresponding to different flow channels; α is a physical property parameter of the measured gas, including but not limited to a single physical property such as thermal conductivity, volume heat capacity and thermal diffusivity, or a mathematical combination of any two or more physical properties; ΔT is the original (or primary) signal data of the flow sensor. For a MEMS calorimetric flow sensor, it is mainly the temperature difference between the upstream and downstream temperature measuring elements of the heating element; c1 and c2 are instrument parameters related to the sensor geometry and flow channel structure; U is the voltage output signal of the flow sensor original (or primary) signal ΔT converted by the measuring bridge;

[0101] The output of each sensor is coupled to obtain the combined output of each sensor f(U(ΔT), U(ΔT n )) and establish the quantitative relationship between gas flow and sensor combination output u~f(U(ΔT), U(ΔT n )); The coupling processing of the outputs of each flow sensor includes, but is not limited to, performing mathematical operations such as addition, subtraction, multiplication, division, and power functions on the output signals of each sensor to eliminate the physical parameter term α; the coupling processing method is to perform mathematical conversion processing on the calibration relationship of each sensor based on similarity theory, eliminate the physical parameter term α in the initial calibration relationship, and obtain a combined output term based on the initial output signal of each sensor;

[0102] The combined output of each sensor includes the following forms:

[0103]

[0104] or

[0105] f(U(ΔT), U(ΔT n ))=c1*ΔT n1 +c2*ΔT n n2 +c3

[0106] The output of the sensor combination after coupling processing is only related to the original (or primary) signal ΔT of each flow sensor, that is, it is a function of the initial voltage output signal U of each flow sensor;

[0107] Among them, ΔT, ΔT n is the temperature difference signal output by the upstream and downstream temperature measuring elements of the flow sensor for the first flow channel and any other flow channel n, c1, c2, c3, n1, n2, ... are instrument coefficients related to the sensor geometry and flow channel structure;

[0108] The quantitative relationship between u and the output signals of the sensors of each flow channel including the main gas flow channel (1) is as follows:

[0109] u~f(U, U1, U2,…, Un)=f(△T(u), △T(u1), △T(u2),…, △T(un))

[0110] The output signals of the flow channel sensors at least include the flow sensor outputs of any two or more flow channels of the main flow channel and the branch flow channel (2);

[0111] S3: Change the temperature or pressure of the reference gas to change the density, volume heat capacity, thermal conductivity and other single physical properties of the measured gas or any mathematical combination of two or more physical properties; obtain the medium flow rate based on the calibration curve query and verify the consistency with the actual flow rate output by the calibration device; if the query value is consistent with the actual value, that is The calibration process ends; if the query value is inconsistent with the true value, Then return to step 2 to adjust the fitting relationship;

[0112] Among them, C is the consistency verification deviation control threshold, which is set manually according to the deviation requirements.

[0113] Optionally, the structural types and working principles of the sensors are different, the output signal of the first sensor (4) is a voltage output signal of a MEMS calorimetric flow sensor, and the second sensor (5) is an original voltage output signal or a processed voltage output signal of a MEMS hot wire anemometer sensor or a time-of-flight sensor, which is a function of the original voltage output signal;

[0114] Optionally, each sensor adopts the same structural type and working principle but has different original acquisition signals. The first sensor (4) and the second sensor (5) in the gas main channel (1) and the branch channel (2) adopt the same MEMS calorimetric flow sensor, based on the same constant temperature difference (CTD) method. The acquisition signal of the former is the original (or primary) output signal of the flow sensor as a function of the temperature difference between upstream and downstream of the heating element; the acquisition signal of the latter is a function of the power of the heating element of the flow sensor.

[0115] Optionally, the first sensor (4) and the second sensor (5) adopt the same structural type but different working principles. The first sensor (4) and the second sensor (5) in the gas main channel (1) and the branch channel (2) adopt the same MEMS calorimetric flow sensor. The former adopts a constant temperature difference (CTD) working mode, and the original (or primary) output signal of the flow sensor is a function of the temperature difference between the upstream and downstream of the heating element; the latter adopts a constant power (CP) working mode, and the original (or primary) output signal of the flow sensor is also a function of the temperature difference between the upstream and downstream of the heating element.

[0116] The calibration process of the multi-component gas flow compensation device described in this embodiment, the detection process of the first sensor (4) and the second sensor (5) is as follows:

[0117] 1): Each flow channel sensor performs flow detection, i.e., the first sensor (4) and the second sensor (5) in the gas main flow channel (1) and the branch flow channel (2) obtain the output signals U, U1, U2, ..., Un of the sensors corresponding to different gas flow rates (volume u, standard volume V, mass m) passing through the medium;

[0118] 2): Calculation of sensor flow combination output items: According to the sensor coupling processing method obtained in the calibration stage, calculate the sensor combination output items f(U, U1, U2, ..., Un);

[0119] 3) Flow measurement: Obtain the sensor combination output item f(U, U1, U2, ..., Un) according to step 2, check the flow sensor calibration curve or data mapping table, u ~ f(U, U1, U2, ..., Un), and obtain the actual gas flow rate; the gas flow rate includes volume flow u, standard volume flow V and mass flow m;

[0120] Furthermore, in the above detection process, when the measured medium is a single-component gas or a multi-component gas with relatively stable components, the output of each sensor can be directly used as a separate metering module.

[0121] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principles of the present invention. These improvements should also be regarded as the scope of protection of the present invention.

Claims

1. A multi-component gas flow compensation device, characterized in that: include: A gas main channel (1), a group of branch channels (2) and an outlet channel (3), wherein the branch channel (2) is arranged on one side of the gas main channel (1), and the outlet channel (3) is arranged at one end of the branch channel (2) away from the gas main channel (1), a first sensor (4) and a second sensor (5) are respectively provided in the gas main channel (1) and the branch channel (2), and the flow velocities in the gas main channel (1) and each branch channel (2) are different, and the two are in a nonlinear relationship, and the first sensor (4) and the second sensor (5) are both MEMS calorimetric flow sensors; The compensation method of the multi-component gas flow compensation device has a specific calibration process as follows: 1): the sensor in each flow channel detects the flow rate of the reference gas passing through the corresponding flow channel; 2): By coupling each flow sensor to eliminate the influence of the medium's physical properties, the output of each flow sensor is coupled, including adding, subtracting, multiplying, dividing and power function mathematical operations on the output signals of each sensor to eliminate the physical parameter item α; the coupling processing method is to perform mathematical conversion processing on the calibration relationship of each sensor based on similarity theory, eliminate the physical parameter items in the initial calibration relationship, obtain the flow combination output item based on the initial output signal of each sensor and establish a quantitative relationship between it and the reference gas medium flow rate, that is, couple the output of each sensor to obtain the combined output of each sensor , and establish a quantitative relationship between gas flow and sensor combination output , where △T is the original or primary signal data of the main channel flow sensor, and U is the voltage output signal of the original or primary signal △T of the flow sensor converted by the measuring bridge. It is the temperature difference signal output of the upstream and downstream temperature measuring elements of the flow sensor of the branch channel n; 3): Change the temperature and pressure of the measured gas to verify the physical property independence of the calibration curve. If the query value is consistent with the true value, the calibration process ends. If the query value is different from the true value, return to 2) to adjust the fitting relationship.

2. The multi-component gas flow compensation device according to claim 1, characterized in that: The branch flow channel (2) comprises a first flow channel (21) and a second flow channel (22), wherein a flow blocker (6) is provided in each of the first flow channel (21) and the second flow channel (22), and the flow velocity of the first flow channel (21) or the second flow channel (22) is different from the flow velocity of the main flow channel (1) and is in a nonlinear relationship.

3. The multi-component gas flow compensation device according to claim 2, characterized in that: A second sensor (5) is provided in the first flow channel (21).

4. The multi-component gas flow compensation device according to claim 2, characterized in that: A second sensor (5) is provided in the second flow channel (22).

5. The multi-component gas flow compensation device according to claim 4, characterized in that: A second sensor (5) is provided in each of the first flow channel (21) and the second flow channel (22).

6. The multi-component gas flow compensation device according to claim 5, characterized in that: The first sensor (4) is a MEMS calorimetric flow sensor, and the second sensor (5) is a MEMS anemometer sensor or a MEMS time-of-flight sensor.

7. The calibration process of the multi-component gas flow compensation device according to claim 6, characterized in that: The specific calibration method of the multi-component gas flow compensation device is as follows: At least two thermal flow sensors are provided in the flow channel, using the same MEMS calorimetric flow sensor type. The flow channels are designed so that the flow velocities u, u1, u2, ..., un of each flow channel are different, and the flow velocity change of at least one flow channel is nonlinear with the flow velocity u of the main flow channel, that is, u1=u1(u), u2=u2(u), ..., un=un(u); the branch flow channel is provided with a flow blocker (6) for adjusting the nonlinear relationship between the branch flow velocity un and the flow velocity u of the main flow channel; S1: Using air or nitrogen as the reference gas, measure the voltage outputs U (△T(u), α), U1 (△T(u1), α), U2 (△T(u2), α), ..., Un (△T(un), α) of each branch channel sensor at different main channel flow velocities u, and obtain the quantitative relationship between the main channel velocity u and the main channel sensor voltage output U through data fitting, i.e., the initial calibration curve; The quantitative relationship is as follows: u~ U (△T(u) ,α); Determine the flow velocity of each flow channel according to the initial calibration curve u~U (△T(u), α) and the voltage output signals of each sensor; the voltage output signals of each sensor include U1(△T(u1), α), U2(△T(u2), α), ..., Un(△T(un, α)); The method for determining the flow rate of each flow channel is to substitute the voltage output signal of each sensor into the initial calibration curve fitting formula or query the initial calibration relationship u~U (△T(u),α) mapping table; the flow rate of each flow channel includes the first flow channel flow rate u1, the second flow channel flow rate u2, ..., the flow channel n flow rate un; According to the flow velocity u of each flow channel at different flow rates and the sensor voltage output signal U, the initial calibration curves u1~U1(△T(u1),α), u2~U2(△T(u2),α),……,un~Un(△T(un),α) of each flow channel are obtained; The first sensor (4) and the second sensor (5) use MEMS calorimetric flow sensors with completely identical sensor structures and working principles, and the initial calibration curves or quantitative relationships of the sensors have a unified mathematical expression form, including the following mathematical form: …… Wherein, u, u1, u2 and un are the measured gas flow rates corresponding to different flow channels respectively; α is the physical property parameter of the measured gas, which includes a single physical property such as thermal conductivity, volume heat capacity and thermal diffusivity, or a mathematical combination of any two or more physical properties; △T is the original or primary signal data of the main channel flow sensor. For MEMS calorimetric flow sensors, it is mainly the temperature difference between the upstream and downstream temperature measuring elements of the heating element; c1 and c2 are instrument parameters related to the sensor geometry and flow channel structure; U is the voltage output signal of the flow sensor original or primary signal △T converted by the measuring bridge; The combined output of each sensor includes the following forms: or The output item of the sensor combination after coupling processing is only related to the original or primary signal of each flow sensor, that is, it is a function of the initial voltage output signal U of each flow sensor; in, 、 is the temperature difference signal output of the upstream and downstream temperature measuring elements of the flow sensor between the main channel and any other branch channel n, c1, c2, c3, n1, n2... are instrument coefficients related to the sensor geometry and flow channel structure; The quantitative relationship between u and the output signals of the sensors of each flow channel including the main gas flow channel (1) is as follows: u ~ f(U, U1, U2,..., Un) = f(△T(u), △T(u1), △T(u2),..., △T(un)) The output signals of the flow channel sensors at least include the flow sensor outputs of any one or more flow channels of the gas main flow channel (1) and the branch flow channel (2); S3: Change the temperature or pressure of the reference gas to change the density, volume heat capacity, thermal conductivity, or any mathematical combination of two or more physical properties of the measured gas; obtain the medium flow rate based on the calibration curve query and verify its consistency with the actual flow rate output by the calibration device; if the query value is consistent with the actual value, then , then the calibration process ends; if the query value is inconsistent with the true value, that is , then return to step 2 to adjust the fitting relationship; in, The deviation control threshold for consistency verification is set manually based on the deviation requirements.

8. The calibration process of the multi-component gas flow compensation device according to claim 6, characterized in that: The detection process of the first sensor (4) and the second sensor (5) is as follows: 1): each flow channel sensor performs flow detection, that is, the first sensor (4) and the second sensor (5) in the gas main flow channel (1) and the branch flow channel (2) obtain the output signals U, U1, U2, ..., Un of the sensors corresponding to different gas flow rates passing through the medium; 2): Calculation of sensor flow combination output items: According to the sensor coupling processing method obtained in the calibration stage, calculate the sensor combination output items f(U, U1, U2, ..., Un); 3): Flow measurement: According to step 2, obtain the sensor combination output item f(U, U1, U2, ..., Un), check the flow sensor calibration curve or data mapping table, u ~ f(U, U1, U2, ..., Un), and obtain the actual gas flow rate; Furthermore, in the above detection process, when the measured medium is a single-component gas or a multi-component gas with relatively stable components, the output of each sensor can be directly used as a separate metering module.

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