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CN-121986251-A - Flow rate estimation device and flow rate estimation method

CN121986251ACN 121986251 ACN121986251 ACN 121986251ACN-121986251-A

Abstract

The flow rate estimation device (20) is provided with a first flow rate calculation unit (64) that calculates a first flow rate value (Q1) of a gas (G) flowing in a pipeline (10) when the gas forms a laminar flow, a second flow rate calculation unit (66) that calculates a second flow rate value (Q2) of the gas when the gas forms a turbulent flow, and an estimation unit (68) that estimates the flow rate of the gas by weighted-averaging the first flow rate value and the second flow rate value using a distribution ratio (alpha) corresponding to the pipeline width (D) and the pipeline length (L) of the pipeline.

Inventors

  • KATSUMATA KOICHI
  • OSHIMA YUTA

Assignees

  • SMC株式会社

Dates

Publication Date
20260505
Application Date
20240603
Priority Date
20231005

Claims (15)

  1. 1. A flow rate estimation device (20) is characterized by comprising: A first flow rate calculation unit (64) that calculates a first flow rate value (Q1) of a gas (G) flowing through a pipe (10) when the gas forms a laminar flow; A second flow rate calculation unit (66) that calculates a second flow rate value (Q2) of the gas when the gas forms turbulence, and And an estimating unit (68) that estimates the flow rate of the gas by weighted-averaging the first flow rate value and the second flow rate value using a distribution ratio (alpha) corresponding to the line width (D) and the line length (L) of the line.
  2. 2. The flow rate estimation device according to claim 1, wherein, The estimating unit performs weighted average of the first flow rate value and the second flow rate value by adding a value obtained by multiplying the distribution ratio of 0 to 1 by the first flow rate value and a value obtained by multiplying a value obtained by subtracting the distribution ratio from 1 by the second flow rate value.
  3. 3. The flow rate estimation device according to claim 2, wherein, The narrower the line width or the longer the line length, the greater the dispensing ratio.
  4. 4. The flow rate estimation device according to claim 1, wherein, In the case where there are a plurality of the lines, the distribution ratio is determined according to the line width and the line length in each of the plurality of the lines.
  5. 5. The flow rate estimation device according to claim 1, wherein, Further provided with a pressure acquisition unit (60) that acquires a first pressure (P1) of the gas flowing into the pipe from a first pressure sensor (36) and acquires a second pressure (P2) of the gas flowing out of the pipe from a second pressure sensor (38), The first flow rate calculation section calculates the first flow rate value based on a pressure difference between the first pressure and the second pressure, The second flow rate calculating section calculates the second flow rate value based on the square root of the pressure difference or the first pressure.
  6. 6. The flow rate estimation device according to claim 5, wherein, Further comprises a temperature acquisition unit (62) for acquiring the temperature (T1) of the gas, The first flow rate calculating section calculates the first flow rate value based on the pressure difference and the temperature of the gas, The second flow amount calculating section calculates the second flow amount value based on the pressure difference or the first pressure and the temperature of the gas, The second flow rate calculation section calculates the second flow rate value using the pressure difference when a pressure ratio of the first pressure to the second pressure is smaller than a prescribed ratio, The second flow rate calculation unit calculates the second flow rate value using the first pressure when the pressure ratio is equal to or greater than the predetermined ratio.
  7. 7. The flow rate estimation device according to any one of claims 1 to 6, characterized in that, The estimating unit estimates the flow rate of the gas by correcting a weighted average value (QWA) obtained by weighted-averaging the first flow rate value and the second flow rate value based on the temperature (T2) of the pipe and the temperature (T3) of the surrounding of the pipe.
  8. 8. The flow rate estimation device according to claim 1, wherein, The conduit is formed in a plate-like member (80) having a rectangular cross section (RS), The rectangular shape formed by the outer periphery of the rectangular cross section has an aspect ratio (R) of 1 to 2.
  9. 9. A flow rate estimation method, comprising: a first flow rate calculating step of calculating a first flow rate value of a gas flowing in a pipe in a case where the gas forms a laminar flow; A second flow rate calculating step of calculating a second flow rate value of the gas in the case where the gas forms turbulence, and And estimating a flow rate of the gas by weighted-averaging the first flow rate value and the second flow rate value using a distribution ratio corresponding to a line width and a line length of the line.
  10. 10. The flow rate estimation method according to claim 9, wherein, In the estimating step, the first flow rate value and the second flow rate value are weighted and averaged by adding a value obtained by multiplying the distribution ratio of 0 to 1 by the first flow rate value and a value obtained by multiplying a value obtained by subtracting the distribution ratio of 1 by the second flow rate value.
  11. 11. The flow rate estimation method according to claim 10, wherein, The narrower the line width or the longer the line length, the greater the dispensing ratio.
  12. 12. The flow rate estimation method according to claim 9, wherein, In the case where there are a plurality of the lines, the distribution ratio is determined according to the line width and the line length in each of the plurality of the lines.
  13. 13. The flow rate estimation method according to claim 9, wherein, Further comprising a pressure acquisition step of acquiring a first pressure of the gas flowing into the pipe from a first pressure sensor and acquiring a second pressure of the gas flowing out of the pipe from a second pressure sensor, In the first flow amount calculating step, the first flow amount value is calculated based on a pressure difference between the first pressure and the second pressure, In the second flow amount calculating step, the second flow amount value is calculated based on the square root of the pressure difference or the first pressure.
  14. 14. The flow rate estimation method according to claim 13, wherein, Further comprising a temperature acquisition step of acquiring the temperature of the gas, In the first flow amount calculating step, the first flow amount value is calculated based on the pressure difference and the temperature of the gas, In the second flow amount calculating step, the second flow amount value is calculated based on the pressure difference or the first pressure, and the temperature of the gas, In the event that the pressure ratio of the first pressure to the second pressure is less than a prescribed ratio, the pressure difference is used to calculate the second flow value, The second flow value is calculated using the first pressure when the pressure ratio is above the prescribed ratio.
  15. 15. The flow rate estimation method according to any one of claims 9 to 14, characterized in that, In the estimating step, the flow rate of the gas is estimated by correcting a value obtained by weighted-averaging the first flow rate value and the second flow rate value based on the temperature of the pipe and the temperature around the pipe.

Description

Flow rate estimation device and flow rate estimation method Technical Field The present invention relates to a flow rate estimation device and a flow rate estimation method. Background Japanese patent application laid-open No. 2001-194193 discloses a flowmeter in which a laminar flow meter is provided upstream of a measurement pipe, and a vortex shedding flow meter is provided downstream of the measurement pipe. The flowmeter is capable of measuring a wide flow range from a minute flow region to a large flow region. According to the flowmeter disclosed in japanese patent application laid-open No. 2001-194193, a pipe (tubule) for measuring a flow rate by a laminar flow flowmeter is provided. In order to expand the flow measurement area to a flow rate where one pipe does not form a laminar flow, it is necessary to use a plurality of pipes forming a laminar flow. Therefore, there is a problem that the flow meter is enlarged. A vortex generator for measuring the flow rate by the vortex shedding flowmeter is mounted in the tube of the measuring tube downstream of the laminar flow flowmeter. Therefore, the flowmeter is further enlarged. The large-sized flowmeter causes an increase in cost. Disclosure of Invention The present invention aims to solve the above problems. A first aspect of the present invention is a flow rate estimating device including a first flow rate calculating unit that calculates a first flow rate value of a gas flowing through a pipe when the gas forms a laminar flow, a second flow rate calculating unit that calculates a second flow rate value of the gas when the gas forms a turbulent flow, and an estimating unit that estimates a flow rate of the gas by weighted-averaging the first flow rate value and the second flow rate value using a distribution ratio corresponding to a pipe width and a pipe length of the pipe. A second aspect of the present invention is a flow rate estimating method including a first flow rate calculating step of calculating a first flow rate value of a gas flowing in a pipe when the gas forms a laminar flow, a second flow rate calculating step of calculating a second flow rate value of the gas when the gas forms a turbulent flow, and an estimating step of estimating a flow rate of the gas by weighted-averaging the first flow rate value and the second flow rate value by using a distribution ratio corresponding to a pipe width and a pipe length of the pipe. According to the present invention, the flow rate estimating device can be miniaturized. The above objects, features and advantages will be easily understood from the following description of the embodiments described with reference to the accompanying drawings. Drawings Fig. 1 is a diagram schematically showing a pipeline and a flow rate estimating device used for estimating the flow rate of gas flowing through the pipeline. Fig. 2 (a) is a view for explaining a rectangular cross section of the piping. Fig. 2 (B) is a view showing a rectangular cross section of the piping. Fig. 2 (C) is a diagram for explaining the line width of the line. Fig. 3 is a view illustrating a plate-like member forming a pipe. Fig. 4 is a diagram for explaining a case where a plurality of pipes are present. Fig. 5 is a flowchart showing a processing procedure of the flow rate estimation processing of the gas. Fig. 6 (a) and 6 (B) are graphs showing the results of evaluation of flow rate estimation in the case where the in-line laminar flow and turbulent flow coexist. Detailed Description Fig. 1 is a diagram schematically showing a pipeline 10 and a flow rate estimating device 20 used for estimating the flow rate of a gas G flowing through the pipeline 10. The gas G flows into the pipe 10 in the flow direction F, flows through the pipe 10, and flows out of the pipe 10. When the line width D of the line 10 is sufficiently wide, the gas G flowing through the line 10 forms turbulence due to the inertial force of the gas G. In this case, the flow rate of the gas G depends on the effective sectional area in the pipe 10. The effective cross-sectional area is a function of the conduit width D of the conduit 10. That is, as described below, the flow rate of the turbulent flow-forming gas G depends on the line width D of the line 10. For example, the wider the line width D of the line 10, the greater the flow rate of the gas G. When the line width D of the line 10 is extremely small, the small flow rate of the gas G flowing through the line 10 forms a laminar flow due to the viscosity of the gas G. In this case, as described below, the flow rate of the gas G depends on the line width D and the line length L of the line 10. That is, the narrower the line width D of the line 10, the smaller the flow rate of the gas G. In addition, the longer the line length L of the line 10, the smaller the flow rate of the gas G. In addition, in the case where the pipe width D of the pipe 10 is neither too narrow nor too wide, laminar flow and turbulent flow coexist in