CN109990971B - An experimental device and method for measuring pressure-variable wind resistance - Google Patents

Abstract

The invention belongs to the technical field of mine ventilation, and discloses a pressure-variable wind resistance determination experimental device and a method, wherein the device comprises an upper computer, a ventilation device and a pressure varying device, the ventilation device comprises an annular closed pipeline and a fan arranged in the annular closed pipeline, a plurality of groups of gas parameter measuring devices are uniformly arranged along the annular closed pipeline, the pressure varying device comprises a pressure source, a constant-pressure storage tank and a pressure-regulating storage tank, the pressure source, the constant-pressure storage tank and the pressure-regulating storage tank are sequentially communicated, a pressure-regulating electromagnetic valve is arranged between the constant-pressure storage tank and the pressure-regulating storage tank, a manual vent valve is arranged between the pressure-regulating storage tank and the annular closed pipeline, a pressure sensor is arranged in the pressure-regulating storage tank, and the gas parameter measuring; the invention researches the change of the atmospheric pressure to the friction resistance coefficient from practical factors, directly determines the friction resistance coefficient, and further determines the friction wind resistance in high and low pressure environments.

Description

An experimental device and method for measuring pressure-variable wind resistance

technical field

The invention belongs to the technical field of mine ventilation, and in particular relates to an experimental device and method for measuring pressure-variable wind resistance.

Background technique

Since the beginning of the 21st century, with the entry of various electrified and mechanized equipment into the mining industry, the scale of underground resource mining has continued to expand. The shallow underground resources in the southeast and the open-pit resources in the northeast that are easy to mine can no longer meet the huge demand for resources by my country's heavy industry enterprises. Therefore, it has become an urgent need to increase the mining of mineral resources in the high-altitude areas in the west and the deep underground areas in the south. Mine ventilation is the most important technical means to ensure safe mining in mines. However, with the expansion of mining scale, the mining trend is developing in a higher and deeper direction, which brings about huge changes in the atmospheric pressure environment and causes the friction resistance of shafts. The change of the coefficient will cause a sharp change in the friction and wind resistance, which will cause trouble to the mine ventilation, and even lead to the occurrence of underground disasters.

The determination of the friction resistance coefficient of the mine roadway is usually carried out by two methods: actual measurement and table look-up. The roadway friction resistance coefficient value measured by the actual measurement method can reflect the resistance characteristics of the mine roadway. However, the measurement environment is poor, the workload is large, and more measurement personnel are needed, which makes it difficult to coordinate the work. The measurement process will inevitably affect the normal production work of the mine. The look-up table method is simple and easy to operate, but the roadway friction resistance coefficient table used in the current mine ventilation design in my country was formulated in the 1980s. Due to the different geomorphological characteristics of the mine and the occurrence conditions of coal, the friction resistance coefficient of the mine roadway is different. Even in the same mine roadway with the same type of support, the frictional resistance coefficient of the mine roadway is also very different due to the influence of the cross-section and length of the roadway. After decades of development in my country's coal mining industry, in addition to great changes in its well type, scale, roadway layout, support structure, etc., the mine as a whole is also developing in a higher and deeper direction, and the existing roadway friction resistance The coefficient table has not kept pace with the times, updated in time, and cannot fully adapt to the current actual situation.

SUMMARY OF THE INVENTION

In order to solve the problems existing in the prior art, the present invention provides a pressure-variable wind resistance measurement experimental device and method, and the technical scheme is as follows:

An experimental device for measuring pressure-variable wind resistance, including a host computer, a ventilation device and a pressure-transforming device, the ventilation device includes an annular closed pipeline and a fan arranged inside the annular closed pipeline, and multiple groups of gases are evenly arranged along the annular closed pipeline A parameter measurement device, the pressure transformation device is used to adjust the air pressure in the annular closed pipeline, and is used to test the wind resistance characteristics of the annular closed pipeline under different air pressure conditions, and the pressure transformation device includes a pressure source, a constant pressure storage tank, and a pressure regulating storage tank. The pressure source, the constant pressure storage tank and the pressure regulating storage tank are connected in sequence, a pressure regulating solenoid valve is arranged between the constant pressure storage tank and the pressure regulating storage tank, the pressure regulating storage tank is provided with a pressure relief valve, and the pressure regulating storage tank is A manual ventilation valve is arranged between the tank and the annular closed pipeline, and an air pressure sensor is arranged in the pressure regulating storage tank. The air pressure sensor transmits the collected data to the upper computer, and the upper computer controls the opening or closing of the pressure regulating solenoid valve and the pressure relief valve according to the received air pressure data.

The gas parameter measuring device includes a multi-function parameter tester and a micro differential pressure gauge.

The annular closed pipeline is made of metal material, and is formed by connecting several sections of metal pipelines end to end. The adjacent metal pipelines are connected by flange joints. The connecting flange, the positioning sealing ring and the sealing ring, the outer wall of the metal pipe between the two connecting flanges is sleeved with a positioning sealing ring, and the two adjacent metal pipes are coaxial with the positioning sealing ring. The ends and the two connecting flanges are sealed by a sealing ring, and the connecting flanges at both ends of the adjacent metal pipes are fixed by bolts.

The positioning sealing ring is provided with a positioning detection hole, a pitot tube is arranged in the positioning detection hole, and the gas parameter measuring device is communicated with the inside of the annular closed pipeline through the pitot tube.

The installation angle of the fan blades of the fan is 30°, 45° or 60°.

Preferably, the installation angle of the fan blades of the fan is 60°.

The constant pressure storage tank is also provided with an exhaust valve.

An experimental method for measuring pressure-variable wind resistance, using the aforementioned experimental device for measuring pressure-variable wind resistance, comprising the following steps:

Step 1. Use the pressure transformer to adjust the pressure in the annular closed pipeline to the value required by the experiment;

Step 2. Turn on the fan, and use the host computer to adjust the fan to the required speed for the experiment. After the dynamic balance is reached in the annular sealed pipe, select a section with relatively stable airflow as the experimental test section, and set the refresh time interval of the gas parameter measurement device to 1S;

Step 3, use the gas parameter measuring device to measure the wind speed v of the experimental test section and the resistance h _f along the way at both ends thereof, and record the experimental data;

Step 4. Repeat steps 2 and 3 to obtain several groups of experimental data at different fan speeds;

Step 5. Repeat steps 1 to 3 to obtain several groups of experimental data under different pressures;

Step 6, processing the experimental data, calculating the frictional resistance coefficient of the experimental test section under different pressure conditions, and finally obtaining the relationship between the pressure and the frictional resistance coefficient;

Step 6.1, calculate the gas flow rate of the experimental test section by the following formula:

Q=Sv

Among them, Q is the unit time flow rate of the gas in the experimental test section, m ³ /s;

S is the cross-sectional area of the annular closed pipeline, m ² ;

v is the average velocity of the gas in the experimental test section, m/s;

Step 6.2, calculate the frictional wind resistance of the experimental test section by the following formula:

R=h _f /Q ₂

Among them, R represents the frictional wind resistance of the experimental test section, kg/m ⁷ ;

h _f represents the frictional resistance along the experimental test section, Pa;

Q is the unit time flow of gas in the experimental test section, m ³ /s;

Step 6.3. Calculate the frictional resistance coefficient of the experimental test section by the following formula:

α=R·S ³ /L·U

Among them, α represents the frictional resistance coefficient of the experimental test section, kg/m ³ ;

R represents the frictional wind resistance of the experimental test section, kg/m ⁷ ;

S is the cross-sectional area of the annular closed pipeline, m ² ;

L represents the length of the experimental test section, m;

U represents the perimeter of the inner wall of the experimental test section, m;

Step 6.4. Repeat step 6.1 to step 6.4 until the frictional resistance coefficient of the experimental test section under all pressure conditions in this experiment is calculated, and the fitting equation of pressure and frictional resistance coefficient α is established to obtain the relationship between pressure and frictional resistance coefficient α .

Compared with the prior art, the beneficial effects of the present invention are:

The invention studies the change of the atmospheric pressure on the frictional resistance coefficient based on the actual factors, directly determines the frictional resistance coefficient, and then can determine the frictional wind resistance under the high and low pressure environment. On the one hand, it can reduce the repetitive workload and labor intensity in the actual project and achieve the goal of saving manpower and material resources. On the other hand, it is a huge prerequisite for the research and establishment of real-time calculation of ventilation network, which is of great significance.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is the partial enlarged schematic diagram of B place in Fig. 1;

Fig. 3 is the partial enlarged schematic diagram of C place in Fig. 1;

Fig. 4 is the structural representation of the flange joint of the present invention;

Fig. 5 is the installation structure schematic diagram of the fan of the present invention;

6 is a schematic diagram of the installation structure of the pitot tube and the gas parameter measuring device of the present invention;

FIG. 7 is a schematic flowchart of the pressure boosting of the annular sealed pipeline by the transformer according to the present invention;

FIG. 8 is a schematic flow chart of the pressure reduction of the annular sealed pipeline by the transformer according to the present invention.

Among them: upper computer 1; annular closed pipeline 21; fan 22; ventilation device 2; transformer device 3; flange joint 4; connecting flange 41; positioning sealing ring 42; sealing ring 43; pitot tube 44; gas parameter measuring device 45.

Detailed ways

It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relationship between various components under a certain posture (as shown in the accompanying drawings). The relative positional relationship, the movement situation, etc., if the specific posture changes, the directional indication also changes accordingly.

As shown in FIG. 1 to FIG. 6 , the present invention provides an experimental device for measuring pressure-variable wind resistance, including a host computer 1, a ventilation device 2 and a pressure-transforming device 3. The ventilation device 2 includes an annular closed pipe 21 and a The fan 22 inside the closed pipe 21 is evenly provided with a plurality of groups of gas parameter measuring devices 45 along the annular closed pipe 21, and the pressure transformation device 3 is used to adjust the air pressure in the annular closed pipe 21, and is used to test different air pressures. The wind resistance characteristics of the annular closed pipeline 21, the pressure transformation device 3 includes a pressure source, a constant pressure storage tank, and a pressure regulating storage tank. Air-inflation dual-purpose air pump, a pressure-regulating solenoid valve is arranged between the constant-pressure storage tank and the pressure-regulating storage tank, a pressure-relief valve is arranged in the pressure-regulating storage tank, and a manual ventilation valve is arranged between the pressure-regulating storage tank and the annular closed pipeline 21 , the pressure regulating storage tank is provided with an air pressure sensor and a buzzer. The gas parameter measuring device 45, the air pressure sensor, the buzzer, the pressure regulating solenoid valve, the pressure relief valve, and the fan 22 are electrically connected to the upper computer 1, and the upper computer 1 is electrically connected through the upper computer. The machine 1 controls the speed of the fan 22, the air pressure sensor transmits the collected data to the upper computer 1, and the upper computer 1 controls the opening or closing of the pressure regulating solenoid valve and the pressure relief valve according to the received air pressure data.

Specifically, the host computer 1 includes a fan console and a transformer console, and the fan 22 includes a servo motor and fan blades. The servo motor and fan console use a 110ST-M06030 AC servo motor set, and the transformer console The control chip model is Mitsubishi FX2N series plc, and the air pressure sensor is specifically Panasonic DP-100Y pressure sensor.

The working principle and process of the transformer device 3 are as follows:

1. As shown in Figure 7, when the pressure in the closed annular closed pipeline 21 is to be adjusted to a certain value P ₁ (0.1Mpa<P ₁ <0.2Mpa) higher than the atmospheric pressure, first open the air pump, and the constant pressure storage tank is Carry out air source pressure storage, so that the air pressure in the constant pressure storage tank is greater than P ₁ ;

The console of the transformer device controls the opening of the pressure regulating solenoid valve to adjust the pressure of the pressure regulating storage tank. The air pressure sensor transmits the collected air pressure data to the console of the transformer device. When the pressure in the pressure regulating storage tank reaches P ₁ , the transformer console controls the buzzer to give an alarm. At this time, the manual ventilation valve is manually opened. At this time, the annular closed pipeline 21 and the pressure regulating storage tank are in a state of communication, until the pressure of the annular closed pipeline 21 and the pressure regulating storage tank are equal, so that the The air pressure in the annular closed pipe 21 is equal to P ₁ .

If the manual ventilation valve is not opened in time, so that the pressure in the pressure regulating storage tank is higher than P ₁ , the air pressure sensor will transmit the collected air pressure data to the console of the transformer device. The pressure in the pressure regulating storage tank can be adjusted to achieve the purpose of self-balancing of the pressure in the pressure regulating storage tank.

2. As shown in Fig. 8, when the pressure in the closed annular closed pipeline 21 is to be adjusted to a certain value P ₂ lower than the atmospheric pressure (0.05Mpa<P ₂ <0.1Mpa), first open the air pump to store the constant pressure. The tank carries out air source pressure storage, so that the air pressure in the constant pressure storage tank is less than P ₂ ;

The pressure regulating device console controls the opening of the pressure regulating solenoid valve to regulate the pressure regulating storage tank. The air pressure sensor transmits the collected air pressure data to the pressure regulating device console. When the pressure in the pressure regulating storage tank reaches P ₂ , the transformer console controls the buzzer to give an alarm. At this time, the manual ventilation valve is manually opened. At this time, the annular closed pipeline 21 and the pressure regulating storage tank are in a state of communication, until the pressure of the annular closed pipeline 21 and the pressure regulating storage tank are equal, so that the The air pressure in the annular closed pipe 21 is equal to P ₂ .

If the manual ventilation valve is not opened in time, so that the pressure in the pressure regulating storage tank is lower than P ₂ , the air pressure sensor will transmit the collected air pressure data to the console of the transformer device, and the console of the transformer device will control the opening of the pressure relief valve to increase the The pressure in the pressure regulating storage tank can be adjusted to achieve the purpose of self-balancing of the pressure in the pressure regulating storage tank.

The gas parameter measuring device 45 includes a multifunctional parameter tester and a micro differential pressure gauge.

Specifically, the pitot tube 44 is an L-shaped pitot tube, one end of which is located inside the annular closed pipe 21 is opposite to the gas flow direction in the annular closed pipe 21, and the gas parameter measuring device 45 is specifically a TSI 9565-P multifunctional ventilation meter, a micro The differential pressure gauge is specifically APG M7000 micro differential pressure gauge.

The annular closed pipeline 21 is made of metal material, and is formed by connecting several sections of metal pipelines end to end. The adjacent metal pipelines are connected by flange joints 4. The connecting flange 41 , the positioning sealing ring 42 and the sealing ring 43 on the outer surface of the pipe, the outer wall of the metal pipe between the two connecting flanges 41 is sleeved with a positioning sealing ring 42 , and the two adjacent metal pipes and the positioning sealing ring 42 Coaxially arranged, both ends of the positioning seal ring 42 and the two connecting flanges 41 are sealed by the seal ring 43, and the connecting flanges 41 at both ends of the adjacent metal pipes are fixed by bolts.

Specifically, the pipe ends at the joints of two adjacent metal pipes protrude from the connection plane of the connection flange 41, forming a state in which the flanges are installed backward. One positioning sealing ring 42 and two sealing rings 43 are used, the inner wall of the positioning sealing ring 42 is matched with the protruding part of the metal pipeline, so that the metal pipeline and the positioning sealing ring 42 are concentric, and the end face of the positioning sealing ring 42 and the connecting flange 41 are clamped. Tighten the sealing ring 43 so that the connection between two adjacent metal pipelines can achieve a better sealing state.

The positioning sealing ring 42 is provided with a positioning detection hole, a pitot tube 44 is installed in the positioning detection hole, and the gas parameter measuring device 45 communicates with the inside of the annular closed pipe 21 through the pitot tube 44 .

In order to meet the experimental needs, other detection equipment or sensors can also be installed in the case where the positioning detection hole is equipped with a special equipment connector.

The installation angle of the fan blades of the fan 22 is adjustable to suit different experimental requirements, and is specifically 60° in this embodiment.

The constant pressure storage tank is also provided with an exhaust valve. After the experiment is over, the pressure in the pressure regulating storage tank and the annular closed pipe 21 can be relieved through the exhaust valve.

An experimental method for measuring pressure-variable wind resistance, using the aforementioned experimental device for measuring pressure-variable wind resistance, comprising the following steps:

Step 1. Use the pressure transformer 3 to adjust the pressure in the annular closed pipe 21 to the value required for the experiment;

Step 2. Turn on the fan 22, and use the host computer 1 to adjust the fan 22 to 500 rpm. After the dynamic balance is reached in the annular sealed pipe, a section with relatively stable airflow is selected as the experimental test section. In this embodiment, the section of the experimental test section is selected. It is a circle, but it can also be a triangle, a trapezoid, a rectangle, a semi-circular arch, and a three-center arch, and the refresh time interval of the gas parameter measuring device 45 is set to 1S;

Step 3, utilize the gas parameter measuring device 45 to measure the wind speed v of the experimental test section and the resistance h _f along the way at both ends thereof, and carry out the record of the experimental data, specifically, record a group of data (including a group of data) every minute. 60 wind speed data and 60 resistance data along the way), so record 6 sets of data;

Specifically, in this embodiment, the experimental test section includes at least two sections of metal pipes. The micro-pressure difference meter at both ends of the experimental test section is used to measure the resistance h _f along the way at both ends of the experimental test section, and the gas parameters in the middle of the experimental test section are measured. The device 45 measures the wind speed v of the experimental test section;

Step 4, repeat step 2 and step 3, adjust the rotational speed of fan 22 to 1000rpm, 1250rpm, 1500rpm, 1750rpm, 2000rpm, 2200rpm respectively, until the maximum speed of fan 22, obtain several groups of experimental data under different fan speed 22;

Step 5. Repeat steps 1 to 3 to obtain several groups of experimental data under different pressures;

Step 6: Process the experimental data, adjust the pressure in the annular closed pipe 21 to 0.07Mpa, 0.08Mpa, 0.09Mpa, 0.11MPa, 0.12MPa, 0.13Mpa respectively, calculate the frictional resistance coefficient of the experimental test section under different pressure conditions, and finally Obtain the relationship between pressure and frictional resistance coefficient;

Specifically, the processing method of the experimental data in step 4 is to first perform normal distribution processing to obtain multiple sets of optimal along-the-path resistance h _f and wind speed v, and then remove the maximum and minimum values to obtain a more accurate sum. objective experimental data.

Step 6.1, calculate the gas flow rate of the experimental test section by the following formula:

Q=Sv

Among them, Q is the unit time flow rate of the gas in the experimental test section, m ³ /s;

S is the cross-sectional area of the annular closed pipe 21, m ² ;

v is the average velocity of the gas in the experimental test section, m/s;

Step 6.2, calculate the frictional wind resistance of the experimental test section by the following formula:

R=h _f /Q ₂

Among them, R represents the frictional wind resistance of the experimental test section, kg/m ⁷ ;

h _f represents the frictional resistance along the experimental test section, Pa;

Q is the unit time flow of gas in the experimental test section, m ³ /s;

Step 6.3. Calculate the frictional resistance coefficient of the experimental test section by the following formula:

α=R·S ³ /L·U

Among them, α represents the frictional resistance coefficient of the experimental test section, kg/m ³ ;

R represents the frictional wind resistance of the experimental test section, kg/m ⁷ ;

S is the cross-sectional area of the annular closed pipe 21, m ² ;

L represents the length of the experimental test section, m;

U represents the perimeter of the inner wall of the experimental test section, m;

Step 6.4 Repeat steps 6.1 to 6.4 until the frictional resistance coefficient of the experimental test section under all pressure conditions in this experiment is calculated, and the fitting equation of pressure and frictional resistance coefficient α is established to obtain the relationship between pressure and frictional resistance coefficient α.

The advantage of the present invention is that the specific relationship between the atmospheric pressure P and the frictional resistance coefficient α can be learned through the fitting equation. On the one hand, solving the difference in frictional resistance coefficient α caused by different geographical locations of mines can reduce the repetitive workload and labor intensity in actual projects and achieve the goal of saving manpower and material resources. Second, because the pressure in the atmosphere changes at any time, the frictional resistance coefficient of the mine also changes at any time, and the determination of the relationship between the atmospheric pressure P and the frictional resistance coefficient α is a huge prerequisite for the research and establishment of real-time calculation of ventilation networks.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the specific embodiments of the present invention can still be modified or equivalent. Any modifications or equivalent substitutions without departing from the spirit and scope of the present invention should be included in the scope of the present claims.

Claims (8)

1. A pressure variable wind resistance determination experimental device is characterized by comprising an upper computer, a ventilation device and a pressure varying device, wherein the ventilation device comprises an annular closed pipeline and a fan arranged in the annular closed pipeline, a plurality of groups of gas parameter measuring devices are uniformly arranged along the annular closed pipeline, the pressure varying device is used for adjusting the air pressure in the annular closed pipeline, the pressure varying device comprises a pressure source, a constant pressure storage tank and a pressure adjusting storage tank, the pressure source, the constant pressure storage tank and the pressure adjusting storage tank are sequentially communicated, a pressure adjusting electromagnetic valve is arranged between the constant pressure storage tank and the pressure adjusting storage tank, the pressure adjusting storage tank is provided with a pressure release valve, a manual vent valve is arranged between the pressure adjusting storage tank and the annular closed pipeline, an air pressure sensor is arranged in the pressure adjusting storage tank, the gas parameter measuring devices, the air pressure sensor, the pressure adjusting, the rotating speed of the fan is controlled by the upper computer, the collected data are transmitted to the upper computer by the air pressure sensor, and the upper computer controls the opening or closing of the pressure regulating electromagnetic valve and the pressure relief valve according to the received air pressure data.

2. The pressure-variable wind resistance measurement experiment device according to claim 1, wherein the gas parameter measurement device comprises a multifunctional parameter tester and a micro differential pressure gauge.

3. The pressure-variable wind resistance measurement experiment device according to claim 2, wherein the annular closed pipeline is made of metal and is formed by connecting a plurality of sections of metal pipelines end to end, adjacent metal pipelines are connected through flange joints, each flange joint comprises a connecting flange, a positioning sealing ring and a sealing ring which are respectively arranged on the outer surfaces of the adjacent metal pipelines, the outer wall of each metal pipeline between the two connecting flanges is sleeved with the positioning sealing ring, the two adjacent metal pipelines and the positioning sealing rings are coaxially arranged, the two ends of each positioning sealing ring and the two connecting flanges are sealed through the sealing rings, and the connecting flanges at the two ends of the adjacent metal pipelines are fixed through bolts.

4. The pressure-variable wind resistance measurement experiment device according to claim 3, wherein the positioning sealing ring is provided with a positioning detection hole, a pitot tube is assembled in the positioning detection hole, and the gas parameter measurement device is communicated with the inside of the annular closed pipeline through the pitot tube.

5. The pressure-variable wind resistance measurement experiment device according to claim 4, wherein the installation angle of the fan blades of the fan is 30 degrees, 45 degrees or 60 degrees.

6. The pressure-variable wind resistance measurement experiment device according to claim 5, wherein the installation angle of the fan blades of the fan is 60 degrees.

7. The pressure-variable wind resistance measurement experiment device according to claim 6, wherein the constant-pressure storage tank is further provided with an exhaust valve.

8. A pressure-variable wind resistance measurement experiment method adopts the pressure-variable wind resistance measurement experiment device as claimed in any one of claims 1 to 7, and is characterized by comprising the following steps:

step 1, adjusting the pressure in the annular closed pipeline to a value required by an experiment by using a pressure changing device;

step 2, starting the fan, adjusting the fan to the rotating speed required by the experiment by using an upper computer, selecting a section with relatively stable wind flow as an experiment testing section after the dynamic balance in the annular sealed pipeline is achieved, and setting the refreshing time interval of the gas parameter measuring device to be 1S;

step 3, measuring the wind speed v of the experimental test section and the on-way resistance h at two ends of the experimental test section by using the gas parameter measuring device_fAnd recording experimental data;

step 4, repeating the step 2 and the step 3 to obtain a plurality of groups of experimental data under different fan rotating speeds;

step 5, repeating the steps 1 to 3 to obtain a plurality of groups of experimental data under different pressures;

step 6, processing the experimental data, calculating the friction resistance coefficient of the experimental test section under different pressure conditions, and finally obtaining the relation between the pressure and the friction resistance coefficient;

step 6.1, calculating the gas flow of the experimental test section by the following formula:

Q＝Sv

wherein Q is the unit time flow of gas in the experimental test section, m³/s；

S is the sectional area of the annular closed pipeline, m²；

v is the average velocity of the gas in the experimental test section, m/s;

step 6.2, calculating the friction wind resistance of the experimental test section according to the following formula:

R＝h_f/Q₂

wherein R represents the frictional wind resistance of the experimental test section, kg/m⁷；

h_fRepresenting the on-way frictional resistance, Pa, of the experimental test section;

q is the flow rate of gas in the experimental test section per unit time m³/s；

Step 6.3, calculating the friction resistance coefficient of the experimental test section by the following formula:

α＝R·S³/L·U

wherein α represents the frictional resistance coefficient in kg/m of the experimental test section³；

R represents the frictional wind resistance of the experimental test section, kg/m⁷；

S is the sectional area of the annular closed pipeline, m²；

L represents the length of the experimental test segment, m;

u represents the perimeter, m, of the inner wall of the experimental test section;

and 6.4, repeating the steps 6.1 to 6.4 until the friction resistance coefficient of the test section of the experiment under all pressure conditions of the experiment is calculated, and establishing a fitting equation of the pressure and the friction resistance coefficient alpha to obtain the relation between the pressure and the friction resistance coefficient alpha.

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