A ventilation tunnel air volume and local heat exchange parameter testing device and a testing method thereof

Abstract

The application belongs to the technical field of tunnel testing, and discloses a ventilation tunnel air volume and local heat exchange parameter testing device and a testing method thereof. The testing device comprises a sensor unit and a central processing unit. The sensor unit comprises a sensor, an acquisition module, a wireless communication module and a power module. The central processing unit comprises a wireless communication module, a data processing module, a data storage module, a touch screen and a power module. The sensor unit is installed on the same section of the tunnel according to a certain number and rule. The application has the following technical effects: long-period continuous measurement of tunnel ventilation parameters is realized; the accuracy and stability of the tunnel ventilation parameter measurement value are ensured; the tunnel use is not affected, and the vehicle is allowed to pass; and the uncertainty of temperature measurement at the high position of the tunnel wall is reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of ventilation tunnel air volume and heat exchange testing, specifically relating to a ventilation tunnel air volume and local heat exchange parameter testing device and its testing method. Background Technology

[0002] With the rapid development of transportation, numerous railway and highway tunnels have been constructed. To ensure traffic safety and passenger comfort within these tunnels, a suitable ventilation system is needed to provide sufficient fresh air and expel exhaust gases and fumes. Accurately measuring the airflow in ventilation tunnels provides crucial data for the design, construction, and operation of tunnel ventilation systems, ensuring that these systems meet design requirements. Furthermore, in water conservancy and hydropower projects, such as ventilation tunnels in pumped-storage power stations, ventilation tunnels serve as a key component of the underground powerhouse's thermal and humidity environment protection system. Testing the tunnel's airflow is crucial for ensuring the effective operation of the underground powerhouse's ventilation system. It also clarifies the temperature and humidity changes as air flows through the tunnel, which is significant for controlling the operation of air conditioning units and managing temperature and humidity within deeply buried structures.

[0003] Traditional methods for arranging measuring points for tunnel airflow testing include the logarithmic Chebyshev method, the logarithmic linear method, and the cross-sectional average wind speed method. These methods all require dividing the flow cross-section into multiple equal-area sub-regions and placing velocity sensors in each sub-region to obtain the flow velocity at the test point. The total airflow of the cross-section is then calculated by area integration. If the air temperature within the sub-region is also measured simultaneously with the velocity, the average air temperature across the cross-section can be obtained. However, traditional airflow testing methods have limitations for ventilation tunnels under normal operating conditions. For example, in railway, highway, or pumped-storage power station ventilation tunnels, due to vehicle and pedestrian traffic during normal operation, stable measuring points cannot be placed in the central area of ​​the tunnel's flow cross-section, making it impossible to obtain test parameter values ​​over a continuous period. Furthermore, the accuracy of sensor test data is also poor due to the influence of vehicles and personnel. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a testing device and method for testing ventilation tunnel air volume and local heat exchange parameters, which can meet the requirements for long-term continuous testing without affecting the normal use of the ventilation tunnel.

[0005] The technical solution adopted in this invention is as follows:

[0006] This invention provides a device for testing the air volume and local heat exchange parameters of a ventilation tunnel, comprising a sensor unit and a central processing unit; the sensor units are installed at various measuring points on the same cross section of the tunnel in a certain number and according to certain rules;

[0007] Each sensor unit includes a sensor, a data acquisition module, a first wireless communication module, and a first power supply module. The sensor includes a hot-wire anemometer and a patch temperature sensor. The hot-wire anemometer measures the air temperature and wind speed at various measuring points near the ventilation tunnel wall, and the patch temperature sensor measures the wall temperature at each measuring point. The data acquisition module acquires the measurement data from the hot-wire anemometer and the patch temperature sensor. The first wireless communication module transmits the measurement data to the central processing unit. The first power supply module provides power to each module of the sensor unit.

[0008] The central processing unit includes a second wireless communication module, a data storage module, a data processing module, a touch screen, and a second power supply module. The second wireless communication module receives measurement data from each of the sensor units. The data processing module performs data quality processing, conversion, and calculation on the measurement data through a preset program. The data storage module stores the measurement data and the calculation results of the data processing module. The touch screen is used for test personnel to input relevant on-site test information and displays the measurement data from the sensor units and the calculation results from the data processing module. The second power supply module provides power to each module of the central processing unit.

[0009] Furthermore, the hot-wire anemometer is a telescopic hinged probe, and the probe measurement point is controlled by the telescopic joint and hinge point; the patch temperature sensor is connected to the acquisition module through a flexible wire, and the non-contact surface of the patch temperature sensor probe is provided with a heat insulation layer.

[0010] Furthermore, the wireless communication method between the sensor unit and the central processing unit is Bluetooth, WiFi, Zigbee, LoRa, NB-IoT, or mobile communication.

[0011] Furthermore, the sampling frequency of the acquisition module can be arbitrarily set by the user through the touch screen of the central processing unit.

[0012] The present invention also provides a testing method for the aforementioned ventilation tunnel airflow and local heat exchange parameter testing device, comprising the following steps:

[0013] Step S1, Testing the airflow in the ventilation tunnel:

[0014] Step S11: Assume there are n measuring points arranged on the same cross section of the ventilation tunnel; for each measuring point i, i = 1, 2, ..., n, the instantaneous wind speed u is collected in real time. i Using formula (1), the hourly average wind speed at measuring point i is obtained.

[0015]

[0016] Where: T represents the acquisition period;

[0017] Step S12, based on the distance r from each measuring point i to the tunnel wall i and the hourly average wind speed at each measuring point i Using formula (2), the hourly average wind speed at each measuring point i is obtained. The calculated average wind speed at the center point of the flow cross section

[0018]

[0019] Where: r0 is the distance from the center point of the flow section to the tunnel wall;

[0020] Step S13: Using formula (3), calculate the hourly average wind speed at the center point of the flow cross section corresponding to each measuring point i. The average wind speed at the center point of the flow cross section is obtained by averaging.

[0021]

[0022] Step S14: Using formula (4), the average wind speed u at the flow cross section is obtained. m :

[0023]

[0024] Step S15: Based on the flow area A of the flow cross section, use formula (5) to obtain the air volume G of the ventilation tunnel in the current collection cycle:

[0025] G = u m ·A (5)

[0026] This completes the test of the air volume in the ventilation tunnel;

[0027] Step S2, testing the local heat transfer parameters of the ventilation tunnel wall, including: the heat transfer per unit area of ​​the tunnel wall and the local convective heat transfer coefficient at the flow section;

[0028] Step S21: For each measuring point i, i = 1, 2, ..., n, the instantaneous wall temperature t is acquired in real time. w,i and instantaneous air temperature t a,i The mean wall temperature at measuring point i is obtained by using formulas (6) and (7) respectively. and average air temperature

[0029]

[0030] Step S22, based on the distance r from each measuring point i to the tunnel wall i and the average wall temperature at each measuring point i. and average air temperature Using formula (8), the average temperature value at the center point of the flow cross section converted to each measuring point i is obtained.

[0031]

[0032] Step S23: Using formula (9), calculate the time-averaged temperature value at the center point of the flow section corresponding to each measuring point i. The average temperature at the center point of the flow cross section is obtained by averaging.

[0033]

[0034] Step S24: Using formula (10), calculate the average wall temperature at each measuring point i. Calculate the average value to obtain the mean value of the wall temperature of the flow section.

[0035]

[0036] Step S25: Using formula (11), the volume average temperature t of the flow cross section is obtained. am :

[0037]

[0038] Step S26: Based on the time-averaged wind speed at the flow cross section and combined with the tunnel turbulent boundary layer model, the local convective heat transfer coefficient h at the flow cross section is obtained using formula (12):

[0039]

[0040] Where: ρ is the air density; c p The specific heat of air; c is the dimensionless temperature of air at the center of the flow cross-section; f The coefficient of frictional resistance;

[0041] Step S27, using formula (13), the heat exchange per unit area of ​​the tunnel wall is obtained:

[0042]

[0043] Where: q is the heat exchange per unit area of ​​the tunnel wall.

[0044] The device and method for testing ventilation tunnel air volume and local heat transfer parameters provided by this invention have the following advantages:

[0045] This invention enables long-term continuous testing and real-time analysis of tunnel ventilation parameters, ensuring the accuracy and stability of the measured values ​​and minimizing the impact of changes in external meteorological parameters and tunnel usage on the test results. Attached Figure Description

[0046] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings, for ease of explanation, the size, dimensions, and shapes of the elements have been slightly adjusted and are not drawn strictly to scale.

[0047] Figure 1 This is a schematic diagram of the ventilation tunnel air volume and local heat exchange parameter testing device of the present invention.

[0048] Figure 2 A schematic diagram of a sensor unit provided in one embodiment of the present invention;

[0049] Figure 3 A sensor unit arrangement diagram provided for one embodiment of the present invention;

[0050] Figure 4 This is a flowchart illustrating the calculation of ventilation tunnel flow rate and local heat exchange parameters according to the present invention.

[0051] In the attached diagram, the components represented by each number are as follows:

[0052] 1. Sensor unit; 2. Flexible wire; 3. Wall temperature sensor; 4. Hot-wire anemometer; 5. Hinge point; 6. Telescopic joint; 7. Fixed bracket; 8. Central processing unit; 9. Tunnel wall; 10. First sensor unit; 11. Second sensor unit; 12. Third sensor unit; 13. Fourth sensor unit; 14. Fifth sensor unit; 15. Sixth sensor unit; 16. Seventh sensor unit. Detailed Implementation

[0053] To better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely exemplary implementations of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Unless otherwise specified, all terms used herein (including engineering and technical terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that, unless expressly stated herein, terms defined in common dictionaries shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not in an idealized or overly formalized sense.

[0055] This invention addresses the problems existing in traditional tunnel airflow testing. By utilizing the velocity and temperature distribution patterns of turbulent airflow within the tunnel and based on Internet of Things (IoT) technology, it simultaneously tests the airflow velocity and temperature near the tunnel wall and the wall temperature at the same cross-section at multiple points. This allows for the acquisition of flow heat transfer parameters such as the total airflow, heat exchange, and local heat transfer coefficient of the tunnel cross-section without affecting the normal use of the tunnel.

[0056] like Figure 1 As shown, the present invention provides a testing device for air volume and local heat exchange parameters in a ventilation tunnel, comprising a sensor unit and a central processing unit; the sensor units are installed at various measuring points on the same cross section of the tunnel in a certain number and according to certain rules;

[0057] Each sensor unit includes a sensor, a data acquisition module, a first wireless communication module, and a first power supply module. The sensor includes a hot-wire anemometer and a patch temperature sensor. The hot-wire anemometer measures the incoming air temperature and wind speed at various measuring points near the ventilation tunnel wall, and the patch temperature sensor measures the wall temperature at each measuring point. The data acquisition module acquires the measurement data from the hot-wire anemometer and the patch temperature sensor. The first wireless communication module transmits the measurement data to the central processing unit. The first power supply module provides power to each module of the sensor unit.

[0058] The central processing unit includes a second wireless communication module, a data storage module, a data processing module, a touch screen, and a second power supply module. The second wireless communication module receives measurement data from each of the sensor units. The data processing module performs data quality processing, conversion, and calculation on the measurement data through a preset program. The data storage module stores the measurement data and the calculation results of the data processing module. The touch screen is used for test personnel to input relevant on-site test information and displays the measurement data from the sensor units and the calculation results from the data processing module. The second power supply module provides power to each module of the central processing unit.

[0059] like Figure 2 and Figure 3 As shown in the illustration, in one embodiment, the hot-wire anemometer is a telescopic hinged probe, and the probe's measurement point can be controlled via the telescopic joint and hinge point. The patch-type temperature sensor is connected to the acquisition module via a flexible wire, and the non-contact surface of the patch-type temperature sensor probe is provided with an insulation layer. The sampling frequency of the acquisition module can be arbitrarily set by the user via the touchscreen of the central processing unit.

[0060] In this invention, the wireless communication method between the sensor unit and the central processing unit is not limited. For example, it can be Bluetooth, WiFi, Zigbee, LoRa, NB-IoT, or mobile communication.

[0061] like Figure 4 As shown, the present invention also provides a testing method for a ventilation tunnel airflow and local heat exchange parameter testing device, comprising the following steps:

[0062] Step S1, Testing the airflow in the ventilation tunnel:

[0063] Step S11: Assume there are n measuring points arranged on the same cross section of the ventilation tunnel; for each measuring point i, i = 1, 2, ..., n, the instantaneous wind speed u at the measuring point location is collected in real time. i Using formula (1), the hourly average wind speed at measuring point i is obtained.

[0064]

[0065] Where: T represents the acquisition period;

[0066] Step S12, based on the distance r from each measuring point i to the tunnel wall i and the hourly average wind speed at each measuring point i Using formula (2), the hourly average wind speed at each measuring point i is obtained. The calculated average wind speed at the center point of the flow cross section m / s:

[0067]

[0068] Where: r0 is the distance from the center point of the flow section to the tunnel wall, in meters; r i Let i be the distance from measuring point i to the tunnel wall, in meters.

[0069] Step S13: Using formula (3), calculate the hourly average wind speed at the center point of the flow cross section corresponding to each measuring point i. The average wind speed at the center point of the flow cross section is obtained by averaging.

[0070]

[0071] Step S14: Using formula (4), the average wind speed u at the flow cross section is obtained. m :

[0072]

[0073] Step S15: Based on the flow area A of the flow cross section, use formula (5) to obtain the air volume G of the ventilation tunnel in the current collection cycle:

[0074] G = u m ·A (5)

[0075] The flow area A is in m² 2 This completes the test of the ventilation tunnel's airflow.

[0076] Step S2, testing the local heat transfer parameters of the ventilation tunnel wall, including: the heat transfer per unit area of ​​the tunnel wall and the local convective heat transfer coefficient at the flow section;

[0077] Step S21: For each measuring point i, i = 1, 2, ..., n, the instantaneous wall temperature t is acquired in real time. w,i and instantaneous air temperature t a,i The unit is °C. The mean wall temperature at measuring point i is obtained by using formulas (6) and (7) respectively. and average air temperature

[0078]

[0079] Step S22, based on the distance r from each measuring point i to the tunnel wall i and the average wall temperature at each measuring point i. and average air temperature Using formula (8), the average temperature value at the center point of the flow cross section converted to each measuring point i is obtained.

[0080]

[0081] Step S23: Using formula (9), calculate the time-averaged temperature value at the center point of the flow section corresponding to each measuring point i. The average temperature at the center point of the flow cross section is obtained by averaging.

[0082]

[0083] Step S24: Using formula (10), calculate the average wall temperature at each measuring point i. Calculate the average value to obtain the mean value of the wall temperature of the flow section.

[0084]

[0085] Step S25: Using formula (11), the volume average temperature t of the flow cross section is obtained. am :

[0086]

[0087] Step S26: Based on the time-averaged wind speed at the flow cross section and combined with the tunnel turbulent boundary layer model, the local convective heat transfer coefficient h at the flow cross section is obtained using formula (12):

[0088]

[0089] Where: ρ is the air density, kg / m³ 3 c p The specific heat of air is J / (kg·K); c is the dimensionless temperature of air at the center of the flow cross-section, in °C. f The coefficient of frictional resistance;

[0090] In this embodiment, and c f The calculation formulas are as follows:

[0091]

[0092] In the formula, Pr is the Prandtl number of air, K is the equivalent roughness height of the wall, d is the hydraulic diameter of the tunnel, and Re is the Reynolds number.

[0093] Step S27, using formula (13), the heat exchange per unit area of ​​the tunnel wall is obtained:

[0094]

[0095] Where: q is the heat exchange per unit area of ​​the tunnel wall.

[0096] The following is an example:

[0097] like Figure 1 As shown, this embodiment of the invention provides a device for testing the airflow and local heat exchange parameters of a ventilation tunnel, including a sensor unit and a central processing unit:

[0098] The sensor unit includes sensors, a data acquisition module, a wireless communication module, and a power supply module. The sensors include a hot-wire anemometer and a patch-type wall temperature sensor, which measure the incoming air temperature and wind speed near the ventilation tunnel wall, and the wall temperature at the same height on the same cross-section, respectively. The data acquisition module uses a 32-bit ARM chip STM32F407VGT6 based on a Cortex-M3 core to acquire the parameter data measured by the hot-wire anemometer and the patch-type temperature sensor. The wireless communication module uses a Bluetooth module to transmit the measurement data to the central processing unit. The power supply module uses a three-terminal regulator LM1117DT-3.3 to output 3.3V voltage to power all modules.

[0099] The central processing unit includes a wireless communication module, a data processing module, a data storage module, a touchscreen, and a power supply module. The wireless communication module uses Bluetooth to receive measurement data from the sensor units. The data processing module uses a 32-bit ARM chip STM32F407VGT6 based on a Cortex-M3 core to perform data quality processing, conversion, and calculations on the measurement data. The data storage module uses a mini-SD card to store measurement data and data processing results. The power supply module uses a three-terminal regulator LM1117DT-3.3 to output 3.3V to power the Bluetooth module, data processing module, and data storage module, and a switching voltage regulator LM2575S-5.0 to output 5V to power the touchscreen.

[0100] like Figure 3 As shown, in this embodiment, seven sensor units are set on the test section, namely: first sensor unit 10, second sensor unit 11, third sensor unit 12, fourth sensor unit 13, fifth sensor unit 14, sixth sensor unit 15, and seventh sensor unit 16.

[0101] Each sensor unit 1 is fixed to the tunnel wall 9 via a mounting bracket 7. The probe direction of the hot-wire anemometer 4 is adjusted via the hinge point 5 to be perpendicular to the incoming flow direction. The wall temperature sensor 3 is fixed to the tunnel wall 9, with insulation cotton installed on the non-contact surface, and is on the same cross-section as the hot-wire anemometer 4. In this embodiment, the central processing unit 8 is mounted on the mounting bracket 7 on one side of the measurement cross-section. It receives measurement signals from all sensor units 1 on the cross-section, analyzes and processes the measurement signals, and finally displays the relevant results on the screen.

[0102] Furthermore, the hot-wire anemometer 4 is a telescopic hinged probe, and the probe measurement point can be controlled through the telescopic joint 6 and the hinge point 5. The wall temperature sensor 3 is a patch-type temperature sensor, which is connected to the sensor unit 1 through a flexible wire 2, and the non-contact surface of the probe is provided with a heat insulation layer.

[0103] This invention enables long-term continuous testing and real-time analysis of tunnel ventilation parameters, ensuring the accuracy and stability of the measured values ​​and minimizing the impact of changes in external meteorological parameters and tunnel usage on the test results.

[0104] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for testing airflow and local heat transfer parameters in a ventilation tunnel, characterized in that, Includes the following steps: Step S1, Testing the airflow in the ventilation tunnel: Step S11, assuming the ventilation tunnel has [missing information] arranged on the same cross section. There are 10 measurement points; for each measurement point... , Real-time data collection of instantaneous wind speed Using formula (1), the measuring points are obtained. wind speed hourly average : （1） Where: T represents the acquisition period; Step S12, based on each measuring point Distance from tunnel wall and each measuring point wind speed hourly average Formula (2) is used to obtain the values ​​for each measuring point. wind speed hourly average The calculated average wind speed at the center point of the flow cross section : （2） in: This is the distance from the center point of the flow section to the tunnel wall; Step S13, using formula (3), measure each measuring point. The corresponding average wind speed at the center point of the flow section The average wind speed at the center point of the flow cross section is obtained by averaging. : （3） Step S14: Using formula (4), the average wind speed of the flow section is obtained. : （4） Step S15, based on the flow area of ​​the flow cross section Formula (5) is used to obtain the air volume of the ventilation tunnel in the current collection cycle. : （5） This completes the test of the air volume in the ventilation tunnel; Step S2, testing the local heat transfer parameters of the ventilation tunnel wall, including: the heat transfer per unit area of ​​the tunnel wall and the local convective heat transfer coefficient at the flow section; Step S21, for each measuring point , Real-time acquisition of instantaneous wall temperature and instantaneous air temperature Using formulas (6) and (7) respectively, the measurement points are obtained. Average wall temperature and average air temperature : （6） （7） Step S22, based on each measuring point Distance from tunnel wall and each measuring point Average wall temperature and average air temperature Formula (8) is used to obtain the values ​​for each measuring point. The average temperature at the center point of the flow cross section after conversion : （8） Step S23, using formula (9), perform measurements on each measuring point. The corresponding average temperature value at the center point of the flow section The average temperature at the center point of the flow cross section is obtained by averaging. : （9） Step S24, using formula (10), perform measurements on each measuring point. The corresponding average wall temperature Calculate the average value to obtain the mean value of the wall temperature of the flow section. : （10） Step S25: Using formula (11), the volume average temperature of the flow section is obtained. : （11） Step S26: Based on the average wind speed at the cross-section and combined with the tunnel turbulent boundary layer model, the local convective heat transfer coefficient at the cross-section is obtained using formula (12). : （12） in: air density; The specific heat of air; The dimensionless temperature of the air at the center of the flow cross section; The coefficient of frictional resistance; Step S27, using formula (13), the heat exchange per unit area of ​​the tunnel wall is obtained: （13） in: The heat exchange per unit area of ​​the tunnel wall; Sensor units are installed at various measuring points on the same cross section of the tunnel in a certain number and according to certain rules; each sensor unit includes a sensor, which includes a hot-wire anemometer and a patch temperature sensor; the hot-wire anemometer is used to measure the air temperature and wind speed at various measuring points near the tunnel wall, and the patch temperature sensor is used to measure the wall temperature at each measuring point.

2. The method for testing air volume and local heat transfer parameters in a ventilation tunnel according to claim 1, characterized in that, The method for testing ventilation tunnel air volume and local heat exchange parameters is implemented using a ventilation tunnel air volume and local heat exchange parameter testing device; the ventilation tunnel air volume and local heat exchange parameter testing device includes a sensor unit and a central processing unit; Each sensor unit includes a sensor, a data acquisition module, a first wireless communication module, and a first power supply module; the data acquisition module is used to acquire measurement data measured by the hot-wire anemometer and the patch temperature sensor; the first wireless communication module is used to transmit the measurement data to the central processing unit; the first power supply module is used to provide power to each module of the sensor unit. The central processing unit includes a second wireless communication module, a data storage module, a data processing module, a touch screen, and a second power supply module; the second wireless communication module is used to receive measurement data from each of the sensor units; the data processing module performs data quality processing, conversion, and calculation on the measurement data through a preset program; the data storage module is used to store the measurement data and the calculation results of the data processing module. The touchscreen is used by testers to input relevant information for on-site testing and to display the measurement data of the sensor unit and the calculation results of the data processing module; the second power module is used to provide power to each module of the central processing unit.

3. The method for testing air volume and local heat exchange parameters in a ventilation tunnel according to claim 2, characterized in that, The hot-wire anemometer is a telescopic hinged probe, and the probe measurement point is controlled by the telescopic joint and hinge point; the patch temperature sensor is connected to the acquisition module through a flexible wire, and the non-contact surface of the patch temperature sensor probe is provided with a heat insulation layer.

4. The method for testing air volume and local heat transfer parameters in a ventilation tunnel according to claim 2, characterized in that, The wireless communication method between the sensor unit and the central processing unit is Bluetooth, WiFi, Zigbee, LoRa, NB-IoT, or mobile communication.

5. The method for testing air volume and local heat exchange parameters in a ventilation tunnel according to claim 2, characterized in that, The sampling frequency of the acquisition module can be arbitrarily set by the user through the touch screen of the central processing unit.

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