Flue gas ultrasonic flow velocity measurement method and system, and computer readable storage medium

Abstract

The invention belongs to the technical field of analysis and detection, and particularly relates to a smoke ultrasonic flow velocity measuring method and system and a computer readable storage medium, an ultrasonic transducer probe is provided with a cooling device with a cooling flow control valve, and the method comprises the steps that S1, the temperature of the ultrasonic transducer probe is collected; s2, whether the temperature of the ultrasonic transducer probe exceeds a preset temperature threshold value or not is judged; if yes, turning to the step S3; if not, the cooling device is closed, and the step S5 is executed; s3, starting a cooling device, calling a cooling amount calculation model, and calculating a target cooling flow based on the temperature of the ultrasonic transducer probe, the temperature of the flue gas, the flow velocity of the flue gas, the contact area of the ultrasonic transducer probe and the flue gas, and the temperature of a cooling medium; s4, a cooling flow control valve is controlled according to the target cooling flow, and then the step S1 is executed; and S5, measuring the flow velocity of the flue gas. The cooling flow is controlled in real time according to the cooling flow calculation model, so that the cost is effectively saved while the cooling flow meets the use requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of analysis and detection, and specifically relates to a flue gas ultrasonic flow velocity measurement method and system, and a computer-readable storage medium. Background Art

[0002] In the industrial flue gas flow measurement industry, the main measuring instrument is the Pitot tube, which has the problems of low measurement accuracy and inaccurate low flow rate measurement; and because it needs to be inserted into the pipeline, the measuring hole is easily corroded by flue gas and blocked by dust or tar, requiring frequent maintenance. In contrast, the flue gas ultrasonic flow meter has the advantages of high accuracy, wide range ratio, easy installation, low maintenance cost, long service life, and no pressure loss.

[0003] However, general ultrasonic flowmeters can only measure working conditions below 150°C. Currently, more and more working conditions exceed 150°C, and some even exceed 200°C. If ultrasonic transducers are used in high temperature environments for a long time, magnetic degradation and performance attenuation will occur, affecting measurement accuracy. Figure 7 As shown, as the temperature rises, when the temperature exceeds the upper limit temperature of the transducer, the signal strength will drop rapidly, and the flow rate value will fluctuate greatly, resulting in inaccurate measurement; although there are ultrasonic flow meters with liquid cooling circulation cooling, how to accurately control the flow rate of the coolant is a difficult problem that needs to be solved urgently.

[0004] In addition, the transducer surface is in direct contact with the flue gas, which contains a large amount of impurities such as dust, tar or water vapor, which will form scale on the transducer surface, causing the sound wave signal energy to attenuate and affect the measurement accuracy. Summary of the invention

[0005] Based on the above-mentioned shortcomings and deficiencies in the prior art, one of the objects of the present invention is to at least solve one or more of the above-mentioned problems in the prior art. In other words, one of the objects of the present invention is to provide a flue gas ultrasonic flow velocity measurement method and system, and a computer-readable storage medium that meet one or more of the above-mentioned needs.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: A method for measuring the ultrasonic flow rate of flue gas, wherein the ultrasonic transducer probe is provided with a cooling device, the cooling device has a cooling flow control valve, and the method for measuring the ultrasonic flow rate of flue gas comprises the following steps: S1, collecting the temperature of the ultrasonic transducer probe; S2, determining whether the temperature of the ultrasonic transducer probe exceeds a preset temperature threshold; if so, proceeding to step S3; if not, turning off the cooling device and proceeding to step S5; S3, turning on the cooling device and calling the cooling amount calculation model to calculate the target cooling flow rate based on the ultrasonic transducer probe temperature, the current flue gas temperature, the current flue gas flow rate, the contact area between the ultrasonic transducer probe and the flue gas, and the cooling medium temperature; S4, controlling the cooling flow control valve according to the target cooling flow, and then going to step S1; S5. Flue gas velocity measurement.

[0007] As a preferred solution, the cooling medium is air, and the corresponding cooling capacity calculation model is: ; in, is the target cooling flow rate, is the current flue gas temperature, is the preset temperature threshold, is the cooling medium temperature, is the contact area between the ultrasonic transducer probe and the smoke, is the current flue gas velocity.

[0008] As a preferred solution, the cooling medium is water, and the corresponding cooling capacity calculation model is: ; in, is the target cooling flow rate, is the current flue gas temperature, is the preset temperature threshold, is the cooling medium temperature, is the contact area between the ultrasonic transducer probe and the smoke, is the current flue gas velocity.

[0009] As a preferred embodiment, the ultrasonic transducer probe is provided with a back-blowing air path for cleaning the ultrasonic transducer probe. The flue gas ultrasonic flow velocity measurement method further comprises the following steps: Sa, collect ultrasonic signals; Sb, determine whether the ultrasonic signal strength is greater than the set backflush threshold; if so, reset the count and go to step Se; if not, go to step Sc; Sc, count cumulatively plus one, determine whether the cumulative count reaches the target number; if so, go to step Sd; if not, go to step Sa; Sd, switch to backflush mode, clean the ultrasonic transducer probe through the backflush gas path, and then go to step Sa; Se. Calculate the flue gas flow rate.

[0010] As a preferred solution, the target number is not less than 6.

[0011] The present invention also provides a flue gas ultrasonic flow velocity measurement system, which uses the flue gas ultrasonic flow velocity measurement method described in the above scheme, and the flue gas ultrasonic flow velocity measurement system comprises: A first ultrasonic transducer probe and a second ultrasonic transducer probe are respectively installed on both sides of the flue, and are used to alternately transmit and receive ultrasonic signals; A cooling device for supplying cooling gas and purge gas, having a first cooling gas supply port, a first purge gas supply port, a second cooling gas supply port, and a second purge gas supply port; A controller, used to control the transmission and reception timing of the first ultrasonic transducer probe and the second ultrasonic transducer probe, and also used to control the switching of the cooling device supplying cooling gas and purge gas; The first ultrasonic transducer probe has a first cooling back-blowing integrated channel, and the two ends of the first cooling back-blowing integrated channel are respectively an air inlet and an air outlet, and the air outlet of the air outlet can purge the end surface to be cleaned of the first ultrasonic transducer probe; the air inlet of the first cooling back-blowing integrated channel is respectively connected to the first cooling air supply port and the first purge air supply port of the cooling device through a three-way valve one; the three-way valve one is connected to the controller signal; The second ultrasonic transducer probe has a second cooling back-blowing integrated channel, and the two ends of the second cooling back-blowing integrated channel are respectively an air inlet and an air outlet, and the air outlet of the air outlet can purge the end face to be cleaned of the second ultrasonic transducer probe; the air inlet of the second cooling back-blowing integrated channel is respectively connected to the second cooling air supply port and the second purge air supply port of the cooling device through three-way valve two; three-way valve two is connected to the controller signal.

[0012] The present invention also provides a flue gas ultrasonic flow velocity measurement system, which uses the flue gas ultrasonic flow velocity measurement method described in the above scheme, and the flue gas ultrasonic flow velocity measurement system comprises: A first ultrasonic transducer probe and a second ultrasonic transducer probe are respectively installed on both sides of the flue, and are used to alternately transmit and receive ultrasonic signals; A cooling device for supplying cooling gas and purge gas, having a first cooling gas supply port, a first purge gas supply port, a second cooling gas supply port, and a second purge gas supply port; A controller, used to control the transmission and reception timing of the first ultrasonic transducer probe and the second ultrasonic transducer probe, and also used to control the switching of the cooling device supplying cooling gas and purge gas; The first ultrasonic transducer probe has a first cooling channel and a first back-blowing air path, the air inlet of the first cooling channel is connected to the first cooling air supply port of the cooling device, the air inlet of the first back-blowing air path is connected to the first purge air supply port of the cooling device, and the air outlet of the first back-blowing air path can purge the end face to be cleaned of the first ultrasonic transducer probe; The second ultrasonic transducer probe has a second cooling channel and a second back-blowing air path. The air inlet of the second cooling channel is connected to the second cooling air supply port of the cooling device, and the air inlet of the second back-blowing air path is connected to the second purge air supply port of the cooling device. The air outlet of the second back-blowing air path can purge the end face to be cleaned of the second ultrasonic transducer probe.

[0013] The present invention also provides a flue gas ultrasonic flow velocity measurement system, which uses the flue gas ultrasonic flow velocity measurement method described in the above scheme, and the flue gas ultrasonic flow velocity measurement system comprises: A first ultrasonic transducer probe and a second ultrasonic transducer probe are respectively installed on both sides of the flue, and are used to alternately transmit and receive ultrasonic signals; a liquid cooling device having a coolant outlet and a coolant inlet; A gas supply device having a first purge gas supply port and a second purge gas supply port; A controller, used to control the transmission and reception timing of the first ultrasonic transducer probe and the second ultrasonic transducer probe, and also used to control the liquid cooling device and the air supply device; The first ultrasonic transducer probe has a first liquid-cooled cooling channel and a first back-blowing gas path, the second ultrasonic transducer probe has a second liquid-cooled cooling channel and a second back-blowing gas path, and the coolant outlet is sequentially connected to the first liquid-cooled cooling channel, the second liquid-cooled cooling channel, and the coolant inlet to form a coolant circulation loop; The air inlet of the first back-blowing air path is connected to the first purge air supply port of the air supply device, and the air outlet of the first back-blowing air path can purge the end surface to be cleaned of the first ultrasonic transducer probe; The air inlet of the second back-blowing air path is connected to the second purge air supply port of the air supply device, and the air outlet of the second back-blowing air path can purge the end face to be cleaned of the second ultrasonic transducer probe.

[0014] The present invention also provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a computer, the computer executes the flue gas ultrasonic flow velocity measurement method as described in any of the above schemes.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention reduces the temperature of the ultrasonic transducer probe by cooling the medium, and is suitable for ultrasonic flow velocity measurement of flue gas under high temperature and harsh working conditions. The cooling flow rate is controlled in real time according to the cooling amount calculation model, so that the cooling flow rate can meet the use requirements while effectively saving costs. When the cooling medium is air, the air forms a protective air curtain on the surface of the transducer probe. (2) The present invention determines the ultrasonic signal strength in real time. When the ultrasonic signal strength is detected to be lower than the set back-blowing threshold, the air flow is turned on to blow the surface of the ultrasonic transducer probe to achieve a cleaning function; (3) The cooling channel and the back-blowing gas path of the present invention can be designed as one body or two bodies, which can meet the needs of different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a structural diagram of a flue gas ultrasonic flow velocity measurement system according to Embodiment 1 of the present invention; Figure 2 is a schematic diagram of a half-section structure of an ultrasonic transducer probe according to Embodiment 1 of the present invention; Figure 3 is a flow chart of the flue gas ultrasonic flow velocity measurement method of this embodiment 1; Figure 4 is a structural diagram of a flue gas ultrasonic flow velocity measurement system according to Embodiment 2 of the present invention; Figure 5 is a structural diagram of a flue gas ultrasonic flow velocity measurement system according to Embodiment 3 of the present invention; Figure 6 is a back-blowing flow chart of the flue gas ultrasonic flow velocity measurement method according to Example 4 of the present invention; Figure 7 It is a correlation curve diagram among ultrasonic signal intensity, flow velocity value and temperature in the prior art. DETAILED DESCRIPTION

[0017] In order to more clearly illustrate the embodiments of the present invention, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other accompanying drawings and other implementation methods can be obtained based on these accompanying drawings without creative work.

[0018] Embodiment 1: like Figure 1 As shown, the flue gas ultrasonic flow velocity measurement system of this embodiment includes a first ultrasonic transducer probe 1, a second ultrasonic transducer probe 2, a controller 3 and a cooling device 4, and the controller 3 is controlled and connected to the first ultrasonic transducer probe 1, the second ultrasonic transducer probe 2 and the cooling device 4 respectively.

[0019] The first ultrasonic transducer probe 1 and the second ultrasonic transducer probe 2 of this embodiment are obliquely installed on both sides of the flue 0 for alternately emitting and receiving ultrasonic signals; the first ultrasonic transducer probe 1 and the second ultrasonic transducer probe 2 have the same structure, and the first ultrasonic transducer probe 1 is taken as an example for detailed description, as shown in FIG. Figure 2As shown, the first ultrasonic transducer probe 1 includes a sleeve-shaped shell 1-1 with openings at both ends and a probe body 1-2 coaxially installed at the front of the sleeve-shaped shell 1-1, the rear end of the sleeve-shaped shell 1-1 has an air inlet 11 connected to its inner cavity, the probe body 1-2 is fixedly embedded in a groove-type mounting seat C, the rear side of the groove-type mounting seat C abuts against the step of the expanded section 1-11 at the front of the sleeve-shaped shell 1-1, and the other side is fixed by a front end cover 1-3 sealed and installed at the front end of the sleeve-shaped shell 1-1; an annular vent C0 is provided at the bottom of the groove in the groove-type mounting seat C, and the outer diameter of the probe body 1-2 and the inner diameter of the groove-type mounting seat C are spaced apart by a predetermined distance. The first air channel C1 is formed by the front end of the probe body 1-2 and the front end cover 1-3 with a preset spacing to form the second air channel C2, thereby forming a cooling back-blowing integrated channel connecting the air inlet 11, the inner cavity of the sleeve-shaped shell 1-1, the annular vent C0, the first air channel C1, the second air channel C2 to the air outlet 130 in the middle of the front end cover 1-3; wherein the rear end of the sleeve-shaped shell 1-1 is sealed and installed with the rear end cover 1-4; in addition, the aperture of the air outlet 130 is smaller than the outer diameter of the probe body 1-2, so that the air outlet direction is reversed, so that the air outlet through the second air channel C2 can purge the end face to be cleaned of the first ultrasonic transducer probe 1. Wherein, the cooling medium air of this embodiment forms a protective air curtain on the probe surface while cooling.

[0020] The cooling device 4 of this embodiment is used to input external compressed air 41 to cool and purge the first ultrasonic transducer probe 1 and the second ultrasonic transducer probe 2. The cooling device 4 has a cooling flow control valve. The specific structure of the cooling device can refer to the existing technology and will not be repeated here.

[0021] Specifically, the cooling device 4 is used to supply cooling gas and purge gas, and has a cooling gas supply port 1 42, a purge gas supply port 1 43, a cooling gas supply port 2 44, and a purge gas supply port 2 45. The air inlet 11 of the cooling and back-blowing integrated channel of the first ultrasonic transducer probe 1 is respectively connected to the cooling gas supply port 2 44 and the purge gas supply port 2 45 of the cooling device 4 through a three-way valve 1 5; the three-way valve 1 5 is connected to the controller 3 signal to achieve intelligent switching between cooling and purge. In addition, the air inlet 21 of the cooling and back-blowing integrated channel of the second ultrasonic transducer probe 2 is respectively connected to the cooling gas supply port 1 42 and the purge gas supply port 1 43 of the cooling device 4 through a three-way valve 2 6; the three-way valve 2 6 is connected to the controller 3 signal to achieve intelligent switching between cooling and purge.

[0022] The controller 3 is used to control the transmission and reception timing of the first ultrasonic transducer probe 1 and the second ultrasonic transducer probe 2 to obtain the flight time, thereby calculating the final flow velocity and flow rate. The specific calculation method can refer to the existing technology and will not be repeated here.

[0023] In addition, the above-mentioned controller 3 is also used to control the switching of the cooling gas and the purge gas supplied by the cooling device 4; when the ultrasonic transducer probe needs to be cooled, the controller 3 controls the cooling device 4 to close the purge gas supply port 1 43 and the purge gas supply port 2 45, and open the cooling gas supply port 1 42 and the cooling gas supply port 2 44; when the ultrasonic transducer probe needs to be back-blown and purged, the controller 3 controls the cooling device 4 to open the purge gas supply port 1 43 and the purge gas supply port 2 45, and close the cooling gas supply port 1 42 and the cooling gas supply port 2 44.

[0024] Based on the above flue gas ultrasonic flow velocity measurement system, such as Figure 3 As shown, the flue gas ultrasonic flow velocity measurement method of this embodiment includes the following steps: (1) Collect the temperature of the ultrasonic transducer probe; Specifically, the temperature can be collected through a temperature sensor built into the ultrasonic transducer probe; (2) Determine whether the temperature of the ultrasonic transducer probe exceeds a preset temperature threshold; if so, proceed to step (3); if not, turn off the cooling device and proceed to step (5); (3) Turn on the cooling device and call the cooling amount calculation model to calculate the target cooling flow rate based on the ultrasonic transducer probe temperature, the current flue gas temperature, the current flue gas flow rate, the contact area between the ultrasonic transducer probe and the flue gas, and the cooling medium temperature; Specifically, according to the law of heat balance, the heat taken away by the cooling medium per unit time is equal to the heat transferred to the probe by the high-temperature flue gas, so that dynamic balance can be achieved; According to the heat formula Q=m*c*ΔT, m is the mass of the object, c is the specific heat capacity, and ΔT is the temperature difference; The mass of an object m=ρ*V, ρ is the density, V is the volume; And volume V=F*t, F is flow rate, t is time; The heat transferred from high temperature flue gas to the probe: ; in, is the current flue gas temperature, is the preset temperature threshold, is the specific heat capacity of flue gas, is the smoke density, is the flow rate of the contact surface between the flue gas and the probe; Flue gas temperature The specific heat capacity of flue gas is obtained by instrument monitoring. The specific heat capacity of flue gas at 400℃ is used as a constant replacement, and the value is 1.151kj / (kg·℃); Smoke density Take a constant instead, the value is 1.0kg / m 3 ; Flue gas flow The contact area between the ultrasonic transducer probe and the flue gas and flue gas velocity Related, available formula Expression, where the contact area It is related to the probe diameter and the length of the probe extending into the flue. It is a fixed value and can be set in advance. Flue gas velocity Obtained by instrument monitoring; Preset temperature thresholds It is related to the transducer model and can be preset; From this, it can be calculated that the heat required to cool the probe to within the preset temperature threshold is: ; The heat taken away by the cooling medium is: ; in, is the cooling medium temperature, is the specific heat capacity of the cooling medium, is the cooling medium density, is the cooling medium flow rate; The cooling medium in this embodiment is air, which has a specific heat capacity of 1.0 kj / (kg·℃) and a density of 1.0 kg / m 3 ; Therefore, the corresponding cooling capacity calculation model is: ; (4) Control the cooling flow control valve according to the target cooling flow, and then go to step (1); (5) Flue gas velocity measurement.

[0025] This embodiment controls the cooling flow rate in real time according to the cooling amount calculation model, so that the cooling flow rate can effectively save costs while meeting the use requirements.

[0026] In addition, this embodiment also provides a computer-readable storage medium, which stores instructions. When the instructions are executed on a computer, the computer executes the above-mentioned flue gas ultrasonic flow velocity measurement method to achieve intelligent measurement of flue gas flow velocity and probe cooling.

[0027] Embodiment 2: The difference between the flue gas ultrasonic flow rate measurement system of this embodiment and that of embodiment 1 is that: the cooling back-blowing integrated channel of the ultrasonic transducer probe adopts a split design; Specifically, Figure 4As shown, the two ultrasonic transducer probes are separately provided with a purge air path 1 K1 and a purge air path 2 K2, which extend along the side wall of the ultrasonic transducer probe to the front end of the ultrasonic transducer probe, and are used to purge the end surface to be cleaned at the front end of the ultrasonic transducer probe; the cooling channel of the ultrasonic transducer probe is still the cooling back-blowing integrated channel structure of Example 1, and no change is required; such a design meets the needs of different application scenarios; For other structures, please refer to Example 1; The flue gas ultrasonic flow velocity measurement method based on the flue gas ultrasonic flow velocity measurement system of this embodiment is consistent with that of Embodiment 1.

[0028] Embodiment 3: The flue gas ultrasonic flow velocity measurement system of this embodiment is different from that of embodiment 1 in that: a combination of liquid cooling and air back-blowing is adopted; Specifically, Figure 5 As shown, the purge gas path is separately provided, that is, it extends along the side wall of the ultrasonic transducer probe to the front end of the ultrasonic transducer probe, and the purge gas path is supplied with gas through the air supply device 7 to realize the purge of the end surface to be cleaned at the front end of the ultrasonic transducer probe; the cooling channel in the ultrasonic transducer probe is a closed channel, having a liquid inlet and a liquid outlet, and an additionally provided liquid cooling device 8 is used to form a coolant circulation loop with the cooling channels of the two ultrasonic transducer probes to realize liquid cooling; such a design meets the needs of different application scenarios; Specifically, the air supply device 7 has an input of external compressed air 70, a purge gas supply port three 71 and a purge gas supply port four 72, the purge gas supply port three 71 is connected to the back-blowing gas path one L1 of the first ultrasonic transducer probe 1, and the purge gas supply port four 72 is connected to the back-blowing gas path two L2 of the second ultrasonic transducer probe 2; the liquid cooling device 8 has a coolant outlet 81 and a coolant inlet 82, the coolant outlet 81 is connected to the liquid inlet two P1 of the cooling channel of the second ultrasonic transducer probe 2, the liquid outlet two P2 of the cooling channel of the second ultrasonic transducer probe 2 is connected to the liquid inlet one P3 of the cooling channel of the first ultrasonic transducer probe 1, and the liquid outlet one P4 of the cooling channel of the first ultrasonic transducer probe 1 is connected to the coolant inlet 82, forming a circulation loop of the coolant.

[0029] The above-mentioned air supply device and liquid cooling device are both connected to the controller for control. The specific structures thereof can refer to the prior art and will not be described in detail here. For other structures, please refer to Example 1; Based on the flue gas ultrasonic flow velocity measurement system of this embodiment, the flue gas ultrasonic flow velocity measurement method of this embodiment is different from that of Embodiment 1 in that: the cooling amount calculation model is different; Specifically, since the cooling medium of this embodiment is water, the corresponding cooling capacity calculation model is: ; in, is the target cooling flow rate, is the current flue gas temperature, is the preset temperature threshold, is the cooling medium temperature, is the contact area between the ultrasonic transducer probe and the smoke, is the current flue gas velocity.

[0030] This embodiment uses water as the cooling medium and controls the cooling flow rate in real time according to different cooling capacity calculation models, so that the cooling flow rate can meet the use requirements while effectively saving costs; For other steps, please refer to Example 1.

[0031] This embodiment also provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a computer, the computer executes the above-mentioned flue gas ultrasonic flow velocity measurement method to realize intelligent flue gas flow velocity measurement and probe cooling.

[0032] Embodiment 4: The difference between the flue gas ultrasonic flow velocity measurement method of this embodiment and that of embodiment 1, embodiment 2 or embodiment 3 is that: a back-blowing and sweeping ultrasonic transducer probe is added to achieve cleaning process; Specifically, Figure 6 As shown, the flue gas ultrasonic flow velocity measurement method also includes the following steps: Sa, collect ultrasonic signals; Sb, determine whether the ultrasonic signal strength is greater than the set backflush threshold; if so, reset the count n and go to step Se; if not, go to step Sc; Sc, count n is accumulated, and it is determined whether the accumulated count n reaches 10 times; if so, it goes to step Sd; if not, the current data is discarded as unqualified, and sampling continues, and it goes to step Sa; Sd, switch to backflush mode, execute the probe backflush process to clean the ultrasonic transducer probe through the backflush gas path, and after cleaning, switch to measurement mode, that is, go to step Sa; Se. Extract the waveform of the ultrasonic signal, calculate the flight time, and calculate the flue gas flow rate.

[0033] This embodiment also provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a computer, the computer executes the above-mentioned flue gas ultrasonic flow velocity measurement method to realize intelligent flue gas flow velocity measurement, probe cooling and backblowing and purging.

[0034] The above description is only a detailed description of the preferred embodiments and principles of the present invention. For ordinary technicians in this field, according to the ideas provided by the present invention, there will be changes in the specific implementation methods, and these changes should also be regarded as the protection scope of the present invention.

Claims

1. A method for measuring flue gas ultrasonic flow velocity, wherein the ultrasonic transducer probe is provided with a cooling device, the cooling device having a cooling flow control valve, characterized in that: The flue gas ultrasonic flow velocity measurement method comprises the following steps: S1, collecting the temperature of the ultrasonic transducer probe; S2, determining whether the temperature of the ultrasonic transducer probe exceeds a preset temperature threshold; if so, proceeding to step S3; if not, turning off the cooling device and proceeding to step S5; S3, turning on the cooling device and calling the cooling amount calculation model to calculate the target cooling flow rate based on the ultrasonic transducer probe temperature, the current flue gas temperature, the current flue gas flow rate, the contact area between the ultrasonic transducer probe and the flue gas, and the cooling medium temperature; S4, controlling the cooling flow control valve according to the target cooling flow, and then going to step S1; S5. Flue gas velocity measurement.

2. The method for measuring flue gas ultrasonic flow velocity according to claim 1, characterized in that: The cooling medium is air, and the corresponding cooling capacity calculation model is: ； in, is the target cooling flow rate, is the current flue gas temperature, is the preset temperature threshold, is the cooling medium temperature, is the contact area between the ultrasonic transducer probe and the smoke, is the current flue gas velocity.

3. The method for measuring flue gas ultrasonic flow velocity according to claim 1, characterized in that: The cooling medium is water, and the corresponding cooling capacity calculation model is: ； in, is the target cooling flow rate, is the current flue gas temperature, is the preset temperature threshold, is the cooling medium temperature, is the contact area between the ultrasonic transducer probe and the smoke, is the current flue gas velocity.

4. According to the method for measuring the ultrasonic flow velocity of flue gas according to any one of claims 1 to 3, the ultrasonic transducer probe is provided with a back-blowing air path for cleaning the ultrasonic transducer probe, characterized in that: The flue gas ultrasonic flow velocity measurement method further comprises the following steps: Sa, collect ultrasonic signals; Sb, determine whether the ultrasonic signal strength is greater than the set backflush threshold; if so, reset the count and go to step Se; if not, go to step Sc; Sc, count cumulatively plus one, determine whether the cumulative count reaches the target number; if so, go to step Sd; if not, go to step Sa; Sd, switch to backflush mode, clean the ultrasonic transducer probe through the backflush gas path, and then go to step Sa; Se. Calculate the flue gas flow rate.

5. The method for measuring flue gas ultrasonic flow velocity according to claim 4, characterized in that: The target number is not less than 6.

6. A flue gas ultrasonic flow velocity measurement system, using the flue gas ultrasonic flow velocity measurement method according to claim 1, 2, 4 or 5, characterized in that: The flue gas ultrasonic flow velocity measurement system comprises: A first ultrasonic transducer probe and a second ultrasonic transducer probe are respectively installed on both sides of the flue, and are used to alternately transmit and receive ultrasonic signals; A cooling device for supplying cooling gas and purge gas, having a first cooling gas supply port, a first purge gas supply port, a second cooling gas supply port, and a second purge gas supply port; A controller, used to control the timing of receiving and transmitting of the first ultrasonic transducer probe and the second ultrasonic transducer probe, and also used to control the switching of the cooling device supplying cooling gas and purge gas; The first ultrasonic transducer probe has a first cooling back-blowing integrated channel, and the two ends of the first cooling back-blowing integrated channel are respectively an air inlet and an air outlet, and the air outlet of the air outlet can purge the end surface to be cleaned of the first ultrasonic transducer probe; the air inlet of the first cooling back-blowing integrated channel is respectively connected to the first cooling air supply port and the first purge air supply port of the cooling device through a three-way valve one; the three-way valve one is connected to the controller signal; The second ultrasonic transducer probe has a second cooling back-blowing integrated channel, and the two ends of the second cooling back-blowing integrated channel are respectively an air inlet and an air outlet, and the air outlet of the air outlet can purge the end face to be cleaned of the second ultrasonic transducer probe; the air inlet of the second cooling back-blowing integrated channel is respectively connected to the second cooling air supply port and the second purge air supply port of the cooling device through three-way valve two; three-way valve two is connected to the controller signal.

7. A flue gas ultrasonic flow velocity measurement system, using the flue gas ultrasonic flow velocity measurement method according to claim 1, 2, 4 or 5, characterized in that: The flue gas ultrasonic flow velocity measurement system comprises: A first ultrasonic transducer probe and a second ultrasonic transducer probe are respectively installed on both sides of the flue, and are used to alternately transmit and receive ultrasonic signals; A cooling device for supplying cooling gas and purge gas, having a first cooling gas supply port, a first purge gas supply port, a second cooling gas supply port, and a second purge gas supply port; A controller, used to control the timing of receiving and transmitting of the first ultrasonic transducer probe and the second ultrasonic transducer probe, and also used to control the switching of the cooling device supplying cooling gas and purge gas; The first ultrasonic transducer probe has a first cooling channel and a first back-blowing air path, the air inlet of the first cooling channel is connected to the first cooling air supply port of the cooling device, the air inlet of the first back-blowing air path is connected to the first purge air supply port of the cooling device, and the air outlet of the first back-blowing air path can purge the end face to be cleaned of the first ultrasonic transducer probe; The second ultrasonic transducer probe has a second cooling channel and a second back-blowing air path. The air inlet of the second cooling channel is connected to the second cooling air supply port of the cooling device, and the air inlet of the second back-blowing air path is connected to the second purge air supply port of the cooling device. The air outlet of the second back-blowing air path can purge the end face to be cleaned of the second ultrasonic transducer probe.

8. A flue gas ultrasonic flow velocity measurement system, using the flue gas ultrasonic flow velocity measurement method according to claim 1, 3, 4 or 5, characterized in that: The flue gas ultrasonic flow velocity measurement system comprises: A first ultrasonic transducer probe and a second ultrasonic transducer probe are respectively installed on both sides of the flue, and are used to alternately transmit and receive ultrasonic signals; a liquid cooling device having a coolant outlet and a coolant inlet; A gas supply device having a first purge gas supply port and a second purge gas supply port; A controller, used to control the transmission and reception timing of the first ultrasonic transducer probe and the second ultrasonic transducer probe, and also used to control the liquid cooling device and the air supply device; The first ultrasonic transducer probe has a first liquid-cooled cooling channel and a first back-blowing gas path, the second ultrasonic transducer probe has a second liquid-cooled cooling channel and a second back-blowing gas path, and the coolant outlet is sequentially connected to the first liquid-cooled cooling channel, the second liquid-cooled cooling channel, and the coolant inlet to form a coolant circulation loop; The air inlet of the first back-blowing air path is connected to the first purge air supply port of the air supply device, and the air outlet of the first back-blowing air path can purge the end surface to be cleaned of the first ultrasonic transducer probe; The air inlet of the second back-blowing air path is connected to the second purge air supply port of the air supply device, and the air outlet of the second back-blowing air path can purge the end face to be cleaned of the second ultrasonic transducer probe.

9. A computer-readable storage medium, wherein instructions are stored in the computer-readable storage medium, characterized in that: When the instructions are executed on a computer, the computer is enabled to execute the method for measuring the ultrasonic flow velocity of flue gas as claimed in any one of claims 1 to 5.

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