An intermittent constant power downhole flow measurement device and method

Abstract

The present invention discloses an intermittent constant-power downhole flow measurement device and method, comprising: a temperature probe, a velocity probe, an external control circuit, and an AD module; wherein the temperature probe and the velocity probe are fixed inside an oil well; the temperature probe and the velocity probe are respectively connected to the AD module; the external control circuit is connected to the velocity probe; the temperature probe is used to measure the ambient temperature of the oil well fluid; the velocity probe is used to heat and collect the internal temperature of the velocity probe; the external control circuit is used to control the heating of the velocity probe; the AD module is used to collect data measured by the temperature probe and the velocity probe, and calculate the actual flow rate based on the collected data. The present invention improves the drawbacks of current thermal flowmeters, such as the PID algorithm being extremely sensitive to ambient temperature, making it difficult to track flow changes over long periods of time and achieving stability.

Description

Technical Field

[0001] The present invention relates to the technical field of flow measurement, and in particular to an intermittent constant-power downhole flow measurement device and method. Background Art

[0002] Flow rate, a key parameter in oil production, is an important research topic in oil well production profile data. Downhole flow rate measurement results can be used to determine the production of mixed fluids in various production layers, providing an important scientific basis for determining the location of abnormally producing sections. With the continuous advancement of oil exploration and development, high water content and low fluid production have become the current status of most oilfield production wells. The low flow rate of low-fluid production wells is difficult to drive the turbine of traditional vortex flowmeters, making it difficult for traditional turbine flowmeters to detect the actual flow rate of produced fluids. Summary of the Invention

[0003] In order to solve the problem that traditional methods in the above-mentioned prior art are difficult to detect the actual flow rate of produced fluid, the present invention provides an intermittent constant-power downhole flow measurement device and method. By using the idea of exchanging time for accuracy, a method combining intermittent constant-power heating and area calculation is adopted to fully utilize the forced convection heat exchange effect of the probe during the two processes of heating and cooling. The disadvantages of the current PID algorithm in the thermal flow meter are that it is extremely sensitive to ambient temperature, making it difficult to track flow changes for a long time and difficult to achieve stability.

[0004] In order to achieve the above technical objectives, the present invention provides an intermittent constant power downhole flow measurement device, comprising:

[0005] Temperature probe, speed probe, external control circuit and AD module;

[0006] Wherein, the temperature measuring probe and the speed measuring probe are fixed inside the oil well;

[0007] The temperature measuring probe and the speed measuring probe are respectively connected to the AD module; the external control circuit is connected to the speed measuring probe;

[0008] The temperature probe is used to measure the ambient temperature of the oil well fluid; the speed probe is used to heat and collect the internal ambient temperature of the speed probe; the external control circuit is used to control the speed probe to heat; the AD module is used to collect data measured by the temperature probe and the speed probe, and calculate the actual flow rate based on the collected data.

[0009] Optionally, the temperature measuring probe includes a temperature measuring cavity and a first temperature sensor;

[0010] The first temperature sensor is fixed inside the temperature measurement cavity, and the first temperature sensor is connected to the AD module through a high-temperature wire;

[0011] Optionally, the speed measuring probe includes a speed measuring cavity, a heater, and a second temperature sensor;

[0012] The heater and the second temperature sensor are fixed inside the speed measurement cavity. The heater is connected to the external control circuit via a high-temperature wire; the second temperature sensor is connected to the AD module via a high-temperature wire.

[0013] In order to better achieve the above technical objectives, the present invention provides an intermittent constant-power downhole flow measurement method, comprising:

[0014] Fixing a temperature probe and a velocity probe inside the oil well, wherein the temperature probe is fixed at an upstream position of the fluid inside the oil well, and the velocity probe is fixed at a downstream position of the fluid inside the oil well;

[0015] The heater is controlled by an external control circuit to heat. When the temperature inside the speed measuring probe exceeds the fluid ambient temperature, this process is called a heating process. Then, the heater is controlled by the external control circuit to stop heating, and the temperature inside the speed measuring probe decreases until it reaches the same temperature as the fluid ambient temperature. This process is called a cooling process. The heater is kept in the stopped heating state. When the temperature inside the speed measuring probe continues to remain consistent with the fluid ambient temperature, this process is called a holding process. The heating process, cooling process, and holding process are recorded as one working cycle.

[0016] The fluid environment temperature and the internal temperature of the velocity probe are collected in real time during the working cycle by using the temperature probe and the velocity probe. Based on the fluid environment temperature and the internal temperature of the velocity probe, the surface area of the fluid environment temperature change and the internal temperature of the velocity probe is calculated;

[0017] Based on the surface area, the actual flow rate is obtained through an experimental calibration method.

[0018] Optionally, the external control circuit generates a pulse width modulation signal to control the heater to perform heating.

[0019] Optionally, the process of calculating the surface area includes:

[0020] The fluid environment temperature and the internal temperature of the velocity probe are collected in real time. The difference between the fluid environment temperature and the internal temperature of the velocity probe is calculated in real time through the equal interval sampling method. Based on the difference, the surface area of the fluid environment temperature change and the internal temperature change of the velocity probe is calculated.

[0021] Optionally, during the real-time acquisition of the fluid ambient temperature, the current fluid ambient temperature is processed by smoothing filtering, and the processed fluid ambient temperature is used in the difference calculation;

[0022] The smoothing filter includes accumulating the current and previous fluid environment temperatures, and then right-shifting the accumulated result to obtain an average value, which is used as the processed fluid environment temperature.

[0023] Optionally, the process of obtaining the actual flow rate includes: drawing a scale template of the surface area and the actual flow rate through an experimental calibration method, and inferring the actual flow rate based on the surface area and the scale template.

[0024] The present invention has the following technical effects:

[0025] Because the surrounding fluid participates in heat exchange during both the heating and cooling processes of the PT1000 temperature sensor, the area method, compared to traditional methods that use either a heating curve or a cooling curve to reflect flow rate, takes both curves into account. This approach leverages time for accuracy and, through intermittent constant-power heating, fully utilizes the forced convection heat exchange effect of the probe during both the heating and cooling processes. This improves the drawback of traditional algorithms that make it difficult to track flow rate changes and achieve stability over long periods of time. Because this method has no moving parts, it also overcomes the drawbacks of traditional turbine flowmeters, which often suffer from turbine hysteresis and stalling, leading to inoperability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 Schematic diagram of the fluid flow detection solution of the present invention;

[0028] Figure 2 This is a schematic diagram of the probe installation of the present invention;

[0029] Figure 3 This is the internal structure diagram of the temperature probe;

[0030] Figure 4 This is the internal structure diagram of the speed measuring probe;

[0031] Figure 5 This is a schematic diagram of the equally spaced sampling area method;

[0032] Figure 6 It is a flowchart of the present invention;

[0033] The following figures are marked as follows: 101 - fluid direction; 102 - temperature probe; 103 - velocity probe; 104 - measured fluid; 105 - oil well; 1021 - first temperature sensor; 1022 - high-temperature wire; 1031 - second temperature sensor; 1032 - heater; 1033 - temperature measuring high-temperature wire; 1034 - heating high-temperature wire; 201 - PT20 operating timing diagram; 202 - temperature change curve inside velocity probe; 203 - heating stage; 204 - cooling stage; 205 - one working cycle ; 206—ambient temperature; 207—temperature rising stage; 208—temperature falling stage; 209—temperature maintaining stage; 301—temperature change curve inside the speed measuring probe at low flow rate; 302—temperature change curve inside the speed measuring probe at high flow rate; 303—AD sampling value at equal time intervals; 3041—area enclosed by the temperature curve 301 of the speed measuring probe at low flow rate and the ambient temperature curve 305; 3042—area enclosed by the temperature curve 301 of the speed measuring probe and the ambient temperature curve 305 at high flow rate; 305—ambient temperature curve. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] In order to solve the problems in the prior art where traditional methods are difficult to detect the true flow rate of produced liquid, the present invention provides the following solutions:

[0036] like Figure 2-4 The present invention provides an intermittent constant-power downhole flow measurement device, comprising: a temperature probe 102, a speed probe 103, an external control circuit and an AD module; wherein the temperature probe and the speed probe are fixed inside an oil well 105; the temperature probe 102 and the speed probe 103 are respectively connected to the AD module; the external control circuit is connected to the speed probe 103; the temperature probe 102 is used to measure the ambient temperature of the oil well fluid; the speed probe 103 is used to heat and collect the internal temperature of the speed probe; the external control circuit is used to control the speed probe 103 to heat; the AD module is used to collect data measured by the temperature probe 102 and the speed probe 103, and calculate the actual flow based on the collected data.

[0037] Optionally, the temperature measuring probe includes a temperature measuring cavity and a first temperature sensor 1021; the first temperature sensor 1021 is fixed inside the temperature measuring cavity, and the first temperature sensor 1021 is connected to the AD module through a high-temperature wire 1022; optionally, the speed measuring probe includes a speed measuring cavity, a heater 1032, and a second temperature sensor 1031; the heater 1032 and the second temperature sensor 1031 are fixed inside the speed measuring cavity, and the heater 1032 is connected to the external control circuit through a heating high-temperature wire 1034; the second temperature sensor 1031 is connected to the AD module through a temperature measuring high-temperature wire 1033.

[0038] In order to better achieve the above technical objectives, the present invention provides an intermittent constant-power downhole flow measurement method, comprising:

[0039] The method includes step 1: using a dual-probe structure, with one probe being a temperature probe 102, placed upstream of the fluid to measure the ambient temperature of the fluid. The other probe being a velocity probe 103, a combination of a temperature sensor and a heater, is placed downstream of the fluid. Step 2: using a control circuit to provide a relatively constant voltage to a heater 1032 built into the velocity probe 103 for a period of time. The heat generated by the heater not only causes the velocity probe itself to increase in temperature but also diffuses into the fluid through the probe's outer wall via heat conduction. When power is removed, the temperature of the velocity probe 103 gradually drops to the ambient temperature. A hold phase occurs before the next temperature increase. The temperature of the velocity probe 103 undergoes a temperature rise phase 207, a temperature fall phase 208, and a hold phase 209, forming a working cycle 205. This temperature rise, temperature fall, and hold phase constitutes a working cycle. Step 3: During a working cycle, the circuit records changes in the resistance of the second temperature sensor 1031 in the velocity probe 103, thereby indirectly recording changes in the temperature within the velocity probe. Step 4: Using the equally spaced sampling method, calculate the area of the curved surface enclosed by the temperature change of the velocity measuring probe 103 and the ambient temperature within a single operating cycle. Step 5: Based on the basic principles of heat conduction, the greater the fluid velocity, the more heat is removed per unit time, and the smaller the area of the curved surface enclosed. Conversely, the slower the fluid velocity, the less heat is removed per unit time, and the larger the area of the curved surface enclosed. Step 6: Using an experimental calibration method, draw a scale template that compares the curved surface area and the actual flow rate. The instrument then infers the actual flow rate based on the current curved surface area and the scale template.

[0040] The measured fluid 104 flows into an oil well 105 from a flow direction 101. A temperature probe 102, located upstream of the fluid, contains a built-in first temperature sensor 1021, a PT1000 temperature sensor, for measuring the fluid's ambient temperature. A velocity probe 103, located downstream of the fluid, contains a heater 1032, a PT20 heater, and a second temperature sensor, a PT1000 temperature sensor. An external control circuit provides a steady-state excitation voltage to the heater 103 for a heating period of t1 to t2203. The heater 1030 generates relatively constant heat energy over a period of time. The second temperature sensor 1031 measures the temperature within the velocity probe 103.

[0041] During the heating process 203, the heater 1032 within the velocity probe 103 generates relatively constant heat energy for a period of time under the action of an external voltage, causing the temperature of the velocity probe 103 to rise. When the external voltage is removed, the heater 1032 ceases operation. Due to forced convection heat exchange, the fluid 104 removes the heat generated by the velocity probe 103, causing the velocity probe 103 to enter a cooling process 204. The temperature of the velocity probe 103 then drops to the ambient temperature 206. The temperature of the velocity probe 103 undergoes a working cycle 205 consisting of a rising phase 207, a falling phase 208, and a holding phase 209.

[0042] The temperature value of the speed measuring probe 103 is obtained by continuous sampling using an AD module using an equal interval sampling method. The surface area enclosed by the temperature curve of the speed measuring probe 103 and the ambient temperature within a working cycle is calculated, and the surface area is used to reflect the fluid flow rate.

[0043] The heater 1032 within the velocity probe 103, stimulated by an external controller, provides heat energy at the same rate according to the operating cycle. Based on the principle of forced convection heat exchange, when the fluid flow rate is low, the velocity probe 103 removes less heat per unit time, and the closed curved surface area (3041) formed by the temperature change curve of the velocity probe 103 and the ambient temperature curve within a working cycle is large. When the fluid flow rate is high, the velocity probe 103 removes more heat per unit time, and the closed curved surface area (3042) formed by the temperature change curve of the velocity probe 103 and the ambient temperature curve is small. Therefore, a larger curved surface area indicates a lower flow rate, while a smaller curved surface area indicates a higher flow rate.

[0044] The external control circuit generates a pulse width modulation signal PWM of a certain frequency and provides it to the heater 1032. When the PWM signal is 1, the voltage across the heater 1032 can be regarded as a steady-state excitation voltage. Assuming that the duty cycle D of the PWM signal is constant and the output voltage U of the circuit board is constant, then the heating power P = (U 2 / R)*D is constant, and the heat energy Q=P*t generated by the heater 1032 per unit time t is constant.

[0045] In practice, the temperature of the fluid in the wellbore always fluctuates slightly, so the ambient temperature also fluctuates accordingly. To reduce the impact of the ambient temperature, a smoothing filter is used when calculating the current ambient temperature. This involves adding the current and previous ambient temperature samples, for example, 127, and then right-shifting the sum by 7 bits (dividing it by 128) to obtain an average value, which is then considered the current ambient temperature value of 305. This minimizes measurement errors caused by ambient temperature fluctuations.

[0046] When calculating the area enclosed by the temperature response curve of the speed measuring probe, it is necessary to subtract the AD sampling value of the ambient temperature from the AD sampling value of the current speed measuring probe 103 , which can further reduce the impact of the ambient temperature change.

[0047] Because the surrounding fluid participates in heat exchange during the heating and cooling processes of velocity probe 103, this approach leverages time for accuracy, combining intermittent constant-power heating with area calculation. This method fully exploits the forced convection heat exchange effect during both heating and cooling processes, overcoming the drawbacks of traditional algorithms that make it difficult to track flow rate changes and achieve stability over long periods of time.

[0048] In order to better understand the technical solution, the present invention is described in the following manner:

[0049] The technical solution adopted by the present invention is: the measuring device is composed of a temperature measuring probe 102 and a velocity measuring probe 103 installed in an oil well 105, and the measured fluid 104 inside the oil well 105 is Figure 2 The fluid direction 101 marked above flows in, the temperature probe 102 is placed upstream of the fluid, and the speed probe 103 is placed downstream of the fluid, forming a complete flow detection system. Figure 3 As shown, the temperature measuring probe 102 has a built-in first temperature sensor 1021 for detecting the temperature of the measured fluid 104, that is, the ambient temperature 206. Figure 4 As shown, the speed probe 103 has a built-in heater 1032 and a second temperature sensor 1031, wherein the heater 1032 is used to heat the speed probe 103 in the heating stage 203, and the second temperature sensor 1031 is used to detect the temperature inside the speed probe 103. Figure 1In the timing waveform PWM shown in FIG201, the temperature of the speed measuring probe 103 undergoes a working cycle consisting of a rising phase 207, a falling phase 208, and a holding phase 209, generating a temperature change curve 202 over time. Based on this, the area of the closed curve formed by the temperature change curve 202 of the speed measuring probe 103 and the ambient temperature curve 206 is calculated using the equal interval sampling method, as shown in FIG202. Figure 5 As shown. Figure 5 As can be seen in the figure, the area 3041 enclosed by the velocity probe temperature change curve 301 and the ambient temperature curve 305 at low flow rates is larger than the area 3042 enclosed by the velocity probe temperature change curve 302 and the ambient temperature curve 305 at high flow rates. Through experimental calibration, a scale template is drawn to represent the surface area and the actual flow rate. The instrument then infers the actual flow rate based on the current surface area and the scale template.

[0050] More specifically, in order to improve the flow detection efficiency, the above scheme provides a steady-state excitation voltage to the heater 1032 for a heating time of t1 to t2203. 1032 will generate relatively constant heat energy for a period of time. The heat generated by 1032 will diffuse into the fluid through the outer wall of the probe, causing the temperature around the second temperature sensor 1031 to rise. The temperature rise curve of the second temperature sensor 1031 is as follows: Figure 5 The heater 1032 stops heating at time t2. Due to the temperature hysteresis effect, the temperature of the second temperature sensor 1031 will continue to rise for a while until it reaches a peak at time t3. Therefore, it can be considered that the temperature rising period of the second temperature sensor is t1 to t3207.

[0051] In the above scheme, without heat energy supplementation, the second temperature sensor 1031 enters the temperature drop stage 208 from t3 to t4, and the temperature of the second temperature sensor 1031 drops to the same level as the ambient temperature at time t4. The subsequent t4 to t5 period is the temperature maintenance stage 209.

[0052] In the above scheme, a short period of heating by heater 1032 causes the temperature of second temperature sensor 1031 to rise rapidly. After the heat supply from heater 1032 is lost, the temperature of second temperature sensor 1031 slowly decreases due to forced convection of the fluid. The temperature variation pattern of second temperature sensor 1031 is: rapid increase and slow decrease.

[0053] In the above scheme, the Figure 5The surface area is calculated using the equidistant sampling method shown. The sampling value 303 on the curve in the figure is obtained by continuous AD sampling. The area enclosed by the temperature change curve and the ambient temperature can be obtained by adding the AD values. 3041 and 3042 represent the temperature change surface area of the velocity probe at small flow and large flow, respectively. Since the temperature of the fluid in the actual wellbore always fluctuates slightly, in order to weaken the influence of the ambient temperature 305, when calculating the current ambient temperature value 305, smoothing filtering is required, that is, the current and previous ambient temperature sampling values, such as 127, are accumulated, and then the sum of the sampling values is shifted right by 7 bits, that is, divided by 128, to obtain an average value, which is regarded as the current temperature value 305. The advantage of this is to eliminate the measurement error caused by the ambient temperature change as much as possible.

[0054] In the above solution, when calculating the area enclosed by the temperature change curve, the actual approach is to subtract the AD value of the ambient temperature from the AD value of the speed probe temperature currently sampled, which can further reduce the impact of ambient temperature changes.

[0055] The above contents are explained with reference to the accompanying drawings:

[0056] like Figure 1 The figure is a schematic diagram of the fluid flow detection scheme of the present invention. The upper graph 201 is an operating timing diagram of the heater 1032, which uses intermittent constant-power low-frequency PWM wave heating. One operating cycle 205 consists of a heating phase 203 and a cooling phase 204. The lower graph 202 is a temperature change curve of the velocity probe, where t1 to t3 is the temperature rising phase 207, t3 to t4 is the temperature falling phase 208, and t4 to t5 is the temperature maintaining phase 209.

[0057] like Figure 2 As shown in the figure, it is a schematic diagram of the probe installation of the present invention. The measured fluid in the wellbore flows in from the fluid direction 101, the temperature measuring probe 102 is placed upstream of the fluid to detect the fluid environment temperature, and the velocity measuring probe 103 is placed downstream of the fluid to heat and measure the temperature of the velocity measuring probe. The purpose of measuring the fluid flow is achieved by utilizing the forced convection heat exchange effect of the velocity measuring probe during the heating and cooling processes.

[0058] like Figure 3 , which is a diagram of the internal structure of the temperature measuring probe, has a built-in first temperature sensor 1021 connected by two high-temperature wires 1022. The first temperature sensor is used to measure the ambient temperature of the fluid.

[0059] like Figure 4The figure shows the internal structure of the speed probe. The speed probe has a built-in heater 1032 and a second temperature sensor 1031, connected by four high-temperature wires: two high-temperature wires 1033 for temperature measurement and two high-temperature wires 1034 for speed measurement. The heater 1032 heats the speed probe, raising its temperature. The second temperature sensor 1031 measures the temperature of the speed probe.

[0060] like Figure 5 Figure 3 shows a schematic diagram of the equally spaced sampling area method. The left side shows the velocity probe temperature change curve 301 at low flow rates, while the right side shows the temperature change curve 302 around the velocity probe at high flow rates. The areas 3041 and 3042 enclosed by the temperature change curve and the ambient temperature value 305 are derived by summing the AD sampling value 303. The figure shows that the area enclosed at low flow rates is larger than that at high flow rates. This is because at low flow rates, the fluid takes longer to remove the velocity probe's heat. Therefore, a larger area enclosed by the temperature change curve and the ambient temperature value indicates a lower flow rate, and vice versa.

[0061] like Figure 6 As shown in FIG, the process steps of the measurement method are as follows. Figure 2 As shown in the probe installation diagram, when measuring flow, the user first secures the temperature probe 102 upstream of the fluid using an instrument frame and places the velocity probe 103 downstream. The temperature probe 102 detects the fluid temperature before heating, i.e., the ambient temperature. An external control circuit generates a PWM signal, causing the heater 1032 inside the velocity probe 103 to generate relatively constant heat for a period of time before stopping heating and allowing the velocity probe 103 to cool to the ambient temperature. This process constitutes a working cycle. During a working cycle, the second temperature sensor 1031 inside the velocity probe records the temperature changes of the velocity probe 103. The AD module continuously collects the ambient temperature around the temperature probe 103 and the velocity probe temperature. Using an evenly spaced sampling method, the AD converter continuously collects the difference between the temperature of the velocity probe 103 and the ambient temperature, calculating the area of the curved surface enclosed by the temperature change of the velocity probe 103 and the ambient temperature during a working cycle. A larger enclosed area indicates a lower flow rate. A smaller enclosed area indicates a higher flow rate. Through the experimental calibration method, a scale template of the surface area and the actual flow is drawn. The instrument can calculate the actual flow based on the current surface area and the scale template.

[0062] In summary, this invention leverages the forced convection heat exchange effect of the probe during both heating and cooling processes, overcoming the drawbacks of traditional algorithms that make it difficult to track flow rate changes and achieve stability over long periods of time. Because this method has no moving parts, it also overcomes the drawbacks of traditional turbine flowmeters, which often suffer from turbine hysteresis and stalling, leading to inoperability.

[0063] The present invention can also be used in the following occasions: 1. Measurement of micro flow of surface liquid; 2. Scientific research institutions studying downhole flow measurement.

[0064] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A measurement method based on an intermittent constant power downhole flow measurement device, characterized in that: The intermittent constant power downhole flow measurement device comprises: Temperature probe, speed probe, external control circuit and AD module; Wherein, the temperature measuring probe and the speed measuring probe are fixed inside the oil well; The temperature measuring probe and the speed measuring probe are respectively connected to the AD module; the external control circuit is connected to the speed measuring probe; The temperature probe is used to measure the ambient temperature of the oil well fluid; the velocity probe is used to heat and collect the ambient temperature inside the velocity probe; the external control circuit is used to control the heating of the velocity probe; the AD module is used to collect data measured by the temperature probe and the velocity probe, and calculate the actual flow rate based on the collected data; The measurement method based on the intermittent constant power downhole flow measurement device includes: Fixing a temperature probe and a velocity probe inside the oil well, wherein the temperature probe is fixed at an upstream position of the fluid inside the oil well, and the velocity probe is fixed at a downstream position of the fluid inside the oil well; The heater is controlled by an external control circuit to heat. When the temperature inside the speed measuring probe exceeds the fluid ambient temperature, this process is called a heating process. Then, the heater is controlled by the external control circuit to stop heating, and the temperature inside the speed measuring probe decreases until it reaches the same temperature as the fluid ambient temperature. This process is called a cooling process. The heater is kept in the stopped heating state. When the temperature inside the speed measuring probe continues to remain consistent with the fluid ambient temperature, this process is called a holding process. The heating process, cooling process, and holding process are recorded as one working cycle. The fluid environment temperature and the internal temperature of the velocity probe are collected in real time during the working cycle by using the temperature probe and the velocity probe. Based on the fluid environment temperature and the internal temperature of the velocity probe, the surface area of the fluid environment temperature change and the internal temperature of the velocity probe is calculated; Based on the surface area, the actual flow rate is obtained through an experimental calibration method.

2. The measuring method according to claim 1, wherein: The temperature measuring probe includes a temperature measuring cavity and a first temperature sensor; The first temperature sensor is fixed inside the temperature measurement cavity, and the first temperature sensor is connected to the AD module through a high-temperature wire.

3. The measuring method according to claim 1, wherein: The speed measuring probe includes a speed measuring cavity, a heater, and a second temperature sensor; The heater and the second temperature sensor are fixed inside the speed measurement cavity. The heater is connected to the external control circuit via a high-temperature wire; the second temperature sensor is connected to the AD module via a high-temperature wire.

4. The measuring method according to claim 1, wherein: The external control circuit generates a pulse width modulation signal to control the heater to perform heating.

5. The measuring method according to claim 1, wherein: The process of calculating the surface area includes: The fluid environment temperature and the internal temperature of the velocity probe are collected in real time. The difference between the fluid environment temperature and the internal temperature of the velocity probe is calculated in real time through the equal interval sampling method. Based on the difference, the surface area of the fluid environment temperature change and the internal temperature change of the velocity probe is calculated.

6. The measuring method according to claim 5, wherein: In the process of real-time acquisition of fluid ambient temperature, the current fluid ambient temperature is processed through smoothing filtering, and the processed fluid ambient temperature is used in difference calculation; The smoothing filter includes accumulating the current and previous fluid environment temperatures, and then right-shifting the accumulated result to obtain an average value, which is used as the processed fluid environment temperature.

7. The measurement method according to claim 1, wherein: The process of obtaining actual traffic includes: Through the experimental calibration method, a scale template of the surface area and the actual flow rate is drawn, and the actual flow rate is calculated based on the surface area and the scale template.

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