Method for testing on-way resistance of discharge flue at top of tunnel
By setting test sections in the tunnel exhaust channel and measuring wind pressure and wind speed data, and calculating the tunnel exhaust channel resistance, the problem of difficulty in effectively detecting and evaluating the tunnel smoke exhaust system resistance in the prior art is solved, and the evaluation of the reliability of the tunnel smoke exhaust system and the mastery of the resistance rules are achieved.
Patent Information
- Application Number
- CN202510409846.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-02
- Publication Date
- 2025-05-23
AI Technical Summary
The prior art is difficult to effectively detect and evaluate the complexity of the flue exhaust duct along the route in the tunnel smoke exhaust system, which affects the fire safety and disaster emergency control of tunnel projects.
By setting the test section at every preset spacing in the tunnel exhaust channel, installing the wind pressure measurement components, and using a differential pressure measuring instrument and wind speed measurement components to measure the wind pressure and wind speed data, and calculate the resistance along the exhaust channel along the route.
Accurate measurement of the resistance along the tunnel flue exhaust channel is achieved, helping to determine the reliability of the tunnel engineering smoke exhaust system, and mastering the relevant laws of the resistance along the top centralized smoke exhaust system.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the field of fire protection engineering, and in particular to a method for testing the resistance along a smoke exhaust duct on a tunnel top. Background Art
[0002] In recent years, there are more and more highway tunnel projects in large water bodies. Most of these tunnels use centralized smoke exhaust to solve fire safety and disaster emergency control problems during fires. However, such highway tunnels have large cross-sections and long smoke exhaust distances, and the key design parameters and smoke control strategies of the smoke exhaust system are complex. In particular, the resistance along the exhaust duct has a great impact on the reliability of the tunnel smoke exhaust system. Therefore, the importance of detecting the resistance along the exhaust duct as an important parameter for evaluating the quality of the tunnel centralized smoke exhaust system is self-evident. Summary of the invention
[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for testing the resistance along a smoke exhaust duct at the top of a tunnel.
[0004] In order to solve the above technical problems, the technical solution proposed by the present invention is: a method for testing the resistance along the smoke exhaust duct at the top of a tunnel, comprising the following steps; 1) Select a location outside the tunnel that is connected to the outside atmosphere to arrange the reference point, then set a test section at a preset interval in the tunnel exhaust duct, and install the wind pressure measurement component at the test section; at the same time, measure the cross-sectional area of the exhaust duct; 2) Turn on the smoke exhaust fans at both ends of the tunnel; 3) Use a differential pressure measuring instrument to measure the static pressure difference between the first test section and the reference point; then use the differential pressure measuring instrument to measure the static pressure difference between the two adjacent test sections, and record the temperature and air pressure at the test location; 4) Use the wind pressure measurement assembly to measure the wind speed of each test section; 5) Based on the obtained wind pressure and wind speed data, calculate the resistance along each section of the smoke exhaust duct.
[0005] In the above-mentioned method for testing the resistance along the smoke exhaust duct at the top of the tunnel, preferably, in step 5), the steps of calculating the resistance along the smoke exhaust duct of each section according to the obtained wind pressure and wind speed data are as follows: 5.1) The calculation formula of each detection section is as follows:
[0006] Q is the air volume (m 3 / s), is the wind speed on the ith small area (m / s), is the area of the ith small block (m 2 ); 5.2) The calculation formula for the average wind speed of each detection section is as follows:
[0007] is the average wind speed of the section (m / s), is the total cross-sectional area (m 2 ); 5.3) Calculate the cross-sectional dynamic pressure based on the average wind speed obtained, the formula is as follows:
[0008] is the dynamic pressure (Pa), is the fluid density (kg / m 3 ), is the average wind speed of the section (m / s); 5.4) The calculation formula of the friction resistance coefficient along the two sections is as follows:
[0009] is the total pressure difference between sections (Pa), is the cross-sectional dynamic pressure (Pa).
[0010] In the above-mentioned method for testing the resistance along the smoke exhaust duct at the top of the tunnel, preferably, in the step 4), when measuring the wind speed at the test section, 3 test points are set at 1 / 2 height of the test section, 4 test points are set at 1 / 4 height, and 2 test points are set near the wall.
[0011] In the above-mentioned method for testing the resistance along the smoke exhaust duct at the top of the tunnel, preferably, the wind pressure measurement assembly includes an L-shaped Pitot tube and a fixed bracket, and the L-shaped Pitot tube is arranged on the fixed bracket so that the distance between the static pressure hole of the L-shaped Pitot tube and the bottom of the smoke exhaust duct is a preset distance.
[0012] Compared with the prior art, the advantages of the present invention are: (1) The present invention measures the resistance along the tunnel top smoke exhaust duct through a full-scale experiment, which is helpful to determine the reliability of the tunnel engineering smoke exhaust system and understand the relevant laws of the resistance along the tunnel top centralized smoke exhaust system; (2) The present invention sets a test section at a certain interval, so that the resistance along each section of the smoke exhaust duct can be clearly understood.
[0013] (3) The acceptance test method of the present invention has a simple structure and uses a handheld measuring instrument that is easy to operate and portable, thus reducing manpower and material costs. In addition, the acceptance test method is reasonably designed and highly reliable, and can accurately measure the resistance along the tunnel smoke exhaust duct. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 The present invention is a flowchart of the method for testing the resistance along the smoke exhaust duct at the top of the tunnel.
[0015] Figure 2 It is a structural schematic diagram of the test section in the present invention.
[0016] Figure 3 It is a schematic diagram of the connection of adjacent wind pressure measurement components in the present invention.
[0017] Figure 4 It is a schematic diagram of the arrangement of test points of the wind speed test section in the present invention.
[0018] Figure 5 It is a schematic diagram of the wind pressure measurement component in the present invention.
[0019] Legend 1. Smoke exhaust duct; 11. Smoke exhaust duct test section; 2. Section wind speed test point; 3. Wind pressure measurement component; 31. L-type Pitot tube; 32. Fixed bracket; 321. Square steel pipe; 322. Square base; 4. Rubber hose, 5. Differential pressure measuring instrument. DETAILED DESCRIPTION
[0020] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and carefully in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.
[0021] It should be noted that when an element is described as being "fixed, fixed, connected or connected to" another element, it can be directly fixed, fixed, connected or connected to the other element, or it can be indirectly fixed, fixed, connected or connected to the other element through other intermediate connectors.
[0022] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Example
[0023] like Figure 1 As shown, this embodiment provides a method for testing the resistance along the tunnel top smoke exhaust duct 1, comprising the following steps: 1) Select a location outside the tunnel that is connected to the outside atmosphere to arrange the reference point, then set a test section at a preset interval in the tunnel exhaust duct 1, install the wind pressure measurement component 3 at the test section, and measure the cross-sectional area of the exhaust duct 1. Specifically, select a location outside the tunnel that is connected to the outside atmosphere to arrange the reference point, then enter the tunnel exhaust duct 1 and install the wind pressure measurement component 3 every 60 meters to measure the cross-sectional area of the exhaust duct 1.
[0024] 2) Turn on the smoke exhaust fans at both ends of the tunnel.
[0025] 3) Use the differential pressure measuring instrument 5 to measure the static pressure difference between the first test section and the reference point; then use the differential pressure measuring instrument 5 to measure the static pressure difference between two adjacent test sections, and record the temperature and air pressure at the test location.
[0026] Specifically, the smoke exhaust fans at both ends of the tunnel are turned on. The testers at both ends enter the smoke exhaust duct 1, use the mini differential pressure measuring instrument 5 to measure the static pressure difference between the first test position and the reference point, use the barometer to synchronously measure the temperature and air pressure at the current position, and then use the mini differential pressure measuring instrument 5 to measure the static pressure difference between the two adjacent test positions, and record the temperature and air pressure at the test positions.
[0027] 4) Use the wind pressure measurement component 3 to measure the wind speed of each test section; specifically, when the tester passes through the test section, three test section wind speed test points 2 are set at the heights of 45cm, 90cm, and 135cm on the center line of the cross section. The wind speed was measured at 9 test points in total, including 2 test points at heights of 45cm and 90cm at one-quarter of the cross section and 2 test points near the wall of the cross section.
[0028] 5) Based on the obtained wind pressure and wind speed data, calculate the resistance along each section of the smoke exhaust duct 1.
[0029] In this embodiment, the structure of the tunnel to be inspected is as follows: the main tunnel shield section is 1 km long, the tunnel adopts top centralized smoke exhaust, the cross-section shape of the smoke exhaust duct 1 is arched, and the area of the smoke exhaust duct 1 and the cross street is 13.4m 2 .
[0030] from Figure 1 It can be seen that the invention is used to test the along-the-way resistance of the smoke exhaust duct 1 at the top of the tunnel; the along-the-way resistance acceptance test method obtains the static pressure, dynamic pressure and position pressure in each section of the smoke exhaust duct 1 by testing, and then obtains the total pressure, and then calculates the along-the-way friction resistance coefficient of each section of the smoke exhaust duct 1.
[0031] Figure 1 , Figure 2 , Figure 4 It can be seen that the wind speed data test method of this embodiment requires setting up a smoke exhaust duct test section 11, a test section wind speed test point 2, and a practical handheld anemometer to measure the wind speed. The wind speed measured at the smoke exhaust duct test section 11 is used to calculate the air volume passing through the section, and is arranged at intervals of 60m in the smoke exhaust duct 1; the handheld anemometer is used to record the wind speed data of each test point.
[0032] According to the average wind speed method, the flue test section is divided into several test areas. After the exhaust fan is turned on, the tester enters the exhaust duct 1 and uses a handheld anemometer to record the wind speed at the center of each test area, thereby obtaining the wind speed of the test section; from Figure 1 , Figure 3 , Figure 5 It can be seen that the along-the-line resistance acceptance test method of the present invention requires the use of a mini differential pressure measuring instrument 5, a wind pressure measuring assembly 33, and a rubber hose 4. There are multiple wind pressure measuring assemblies 33, wherein the wind pressure measuring assembly 33 includes an L-shaped pitot tube 31 and a fixing bracket 32.
[0033] The wind pressure measurement assembly 3 uses an L-shaped pitot tube 31 to collect static pressure data. The L-shaped pitot tube 31 is connected to the upper end of the fixed bracket 32, so that the static pressure hole of the L-shaped pitot tube 31 is 900 mm away from the bottom of the smoke exhaust duct 1. The fixed bracket 32 includes a square base 322 and a square steel pipe 321. The side length of the square base 322 is 400 mm. The center of the square base 322 is connected to the square steel pipe 321. The length of the square steel pipe 321 is 800 mm and the outer diameter is 20 mm.
[0034] The installation method of the wind pressure measurement component 3 is as follows: first reserve a hole in the center of the square base 322, place the base in the middle of the test cross section during installation, insert the square steel pipe 321 into the center hole of the base, then bond the base and the square steel pipe 321 with thermosetting adhesive, place the L-shaped Pitot tube 31 on the upper end of the square steel pipe 321, make the static pressure hole of the L-shaped Pitot tube 31 900mm away from the bottom of the smoke exhaust duct 1, and fix the L-shaped Pitot tube 31 with tape.
[0035] When arranging the test device, firstly, a group of wind pressure measurement components 3 are arranged outside the exhaust duct 1 to ensure that they are connected to the atmosphere as a pressure reference point. After entering the exhaust duct 1, a group of wind pressure measurement components 3 are arranged every 60m, and adjacent wind pressure measurement components 3 are connected by rubber hoses 4. The rubber hoses 4 are only connected to the static pressure interface of the L-type pitot tube 31, which is used to measure the static pressure difference between adjacent measurement components.
[0036] from Figure 3 It can be seen that the collection device of the present invention also needs to use a differential pressure measuring instrument 5, which is carried by the test personnel. After arriving at the test location, the differential pressure measuring instrument 5 is connected to two adjacent groups of wind pressure measurement components 3 through a rubber hose 4 to collect the static pressure difference between the two groups of components.
[0037] In this embodiment, in step 5), the resistance along each section of the smoke exhaust duct 1 is calculated according to the obtained wind pressure and wind speed data: 5.1) The calculation formula for each detection section is as follows:
[0038] Q is the air volume (m 3 / s), is the wind speed on the ith small area (m / s), is the area of the ith small block (m 2 ); 5.2) The calculation formula for the average wind speed of each detection section is as follows:
[0039] is the average wind speed of the section (m / s), is the total cross-sectional area (m 2 ); 5.3) Calculate the cross-sectional dynamic pressure based on the average wind speed obtained, the formula is as follows:
[0040] is the dynamic pressure (Pa), is the fluid density (kg / m 3 ), is the average wind speed of the section (m / s); 5.4) The calculation formula of the friction resistance coefficient along the two sections is as follows:
[0041] is the total pressure difference between sections (Pa), is the cross-sectional dynamic pressure (Pa).
[0042] The method for testing the resistance along the tunnel top smoke exhaust duct 1 of this embodiment can accurately measure the resistance along the tunnel smoke exhaust duct 1.
Claims
1. A method for testing the resistance along the smoke exhaust duct at the top of a tunnel, characterized by: The steps include: 1) Select a location outside the tunnel that is connected to the outside atmosphere to arrange the reference point, then set a test section at a preset interval in the tunnel exhaust duct, and install a wind pressure measurement component at the test section to measure the cross-sectional area of the exhaust duct; 2) Turn on the smoke exhaust fans at both ends of the tunnel; 3) Use a differential pressure measuring instrument to measure the static pressure difference between the first test section and the reference point; then use the differential pressure measuring instrument to measure the static pressure difference between two adjacent test sections, and record the temperature and air pressure at the test location; 4) Use the wind pressure measurement assembly to measure the wind speed of each test section; 5) Based on the obtained wind pressure and wind speed data, calculate the resistance along each section of the smoke exhaust duct.
2. The method for testing the resistance along the tunnel top smoke exhaust duct according to claim 1 is characterized in that: In step 5), according to the obtained wind pressure and wind speed data, the steps for calculating the resistance along each section of the exhaust duct are as follows: 5.1) The calculation formula for each detection section is as follows: 3.Q is the air volume, is the wind speed on the ith small area, is the area of the ith small block; 5.2) The calculation formula for the average wind speed of each detection section is as follows:
4. is the average wind speed of the section, is the total cross-sectional area; 5.3) Calculate the cross-sectional dynamic pressure based on the average wind speed obtained, the formula is as follows:
5. is the dynamic pressure, is the fluid density, is the average wind speed of the section; 5.4) The calculation formula of the friction resistance coefficient along the two sections is as follows:
6. is the total pressure difference between sections, is the cross-sectional dynamic pressure.
7. The method for testing the resistance along the tunnel top smoke exhaust duct according to claim 1 is characterized in that: In the step 4), when measuring the wind speed at the test section, 3 test points are set at 1 / 2 height of the test section, 4 test points are set at 1 / 4 height, and 2 test points are set near the wall.
8. The method for testing the resistance along the tunnel top smoke exhaust duct according to claim 1 is characterized in that: The wind pressure measurement assembly includes an L-shaped Pitot tube and a fixed bracket. The L-shaped Pitot tube is arranged on the fixed bracket so that the distance between the static pressure hole of the L-shaped Pitot tube and the bottom of the smoke exhaust duct is a preset distance.