A double-head internal combustion engine tunnel ventilation wind speed optimization method and system

Abstract

The present application relates to the technical field of tunnel ventilation, and discloses a double-head internal combustion engine traction tunnel ventilation wind speed optimization method and system. The method comprises the following steps: calculating the piston wind speed and the relative wind speed of the train passing through the tunnel at each time, dynamically analyzing the diffusion distance of the pollutants from the first head to the second head, evaluating the pollutant concentration at the second head by comparing with the double-head distance, adopting dynamic optimization target wind speed to ensure that the pollutant concentration is always lower than the safety threshold, and finally controlling the ventilation equipment to ventilate the tunnel in real time according to the optimization result. The present application effectively solves the problem of insufficient combustion of the internal combustion engine of the second head caused by the diffusion of pollutants during the operation of the double-head train in the tunnel, significantly improves the traction performance and operation safety of the train, simultaneously realizes the energy-saving optimization of the ventilation system, and provides reliable technical support for the safe operation of high-altitude railway lines.

Description

Technical Field

[0001] This invention relates to the field of tunnel ventilation technology, and in particular to a method and system for optimizing ventilation wind speed in tunnels traction by a dual-head internal combustion engine. Background Technology

[0002] Some railway projects pass through remote mountainous areas, plateaus, and deserts with weak power infrastructure. Due to the difficulty of power facility construction and cross-border coordination, the main railway lines mostly use diesel engine traction technology as a transitional solution. Especially in high-altitude and steep-gradient sections, it is necessary to use double-head coupling traction technology to achieve coordinated control of the front and rear locomotives to meet the traction requirements of continuous gradients and avoid mechanical wear and operational risks caused by overloading of a single power unit.

[0003] When a twin-locomotive train passes through a complex mountainous railway tunnel, the piston-wind effect causes pollutants and dust from the combustion of the internal combustion engine in the front locomotive to spread to the rear. This reduces the oxygen content in the air drawn in by the rear locomotive, leading to incomplete combustion in the internal combustion engine. This can significantly reduce the train's traction capacity and, in high-altitude, steep-gradient tunnels, even pose safety risks such as stopping or reversing. Current industry standards, which require the entire tunnel to be ventilated within 15 minutes after the train exits the tunnel, only consider the impact of pollutants from the previous train on the next train, neglecting the environmental needs of the twin-locomotive train itself while passing through the tunnel. Therefore, they cannot guarantee that the pollutant concentration at the rear locomotive meets safety requirements. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for optimizing ventilation wind speed in tunnels traction by a dual-head internal combustion engine, comprising the following steps: S1. Based on the tunnel structure parameters and train operation parameters, calculate the piston wind speed of the train passing through the tunnel at each time step, and set the initial target wind speed. S2. Based on the current piston wind speed and target wind speed, combined with tunnel structure parameters and train operation parameters, calculate the relative wind speed of the train at the current moment. S3. Based on the relative wind speed, combined with tunnel structure parameters and train operation parameters, calculate the travel distance of the pollutants released by the first locomotive. If the travel distance is less than the distance between the two locomotives, then execute S5; otherwise, execute S4. S4. Based on the travel distance, combined with tunnel structure parameters and train operation parameters, assess the pollutant concentration at the second locomotive head. If the pollutant concentration is less than the concentration threshold, the target wind speed remains unchanged; otherwise, update the target wind speed. S5. Determine whether the corresponding target wind speed has been obtained for all time points. If not, adjust to the next time point and return to execute S2 based on the updated target wind speed. If yes, output the target wind speed corresponding to each time point when the train passes through the tunnel. S6. Control the ventilation equipment to ventilate the tunnel according to the target wind speed corresponding to each moment; The first locomotive is the diesel engine located in front of the train in the direction of travel, and the second locomotive is the diesel engine located behind the train in the direction of travel.

[0005] Furthermore, in S1, based on tunnel structural parameters and train operating parameters, the piston wind speed of the train passing through the tunnel is calculated hourly according to a preset time step, including: The formula for calculating piston wind speed is as follows: ; Among them, v m (t) represents the piston wind speed inside the tunnel at time t, where t represents time, and A, B, and C represent intermediate variables; The formula for calculating intermediate variable A is as follows: ; Where, K m V represents the piston wind action coefficient. T Indicates the train's speed. V represents the resistance coefficient at the tunnel entrance. n L represents the natural wind speed inside the tunnel. T Let l represent the tunnel length, α represent the blockage ratio, and l T Indicates the length of the train; The formula for calculating intermediate variable B is as follows: ; The formula for calculating the intermediate variable C is as follows: ; in, This represents the resistance coefficient of the tunnel section excluding the annular space.

[0006] Furthermore, in S2, the relative wind speed of the train at the current moment is calculated using the following formula: ; Among them, v 差 (t) represents the relative wind speed at time t, v 车 v is the train's running speed. m (t) represents the piston wind speed at time t, F represents the tunnel cross-sectional area, and f T v is the cross-sectional area of ​​the train. 目标 The target wind speed.

[0007] Furthermore, in S3, based on the relative wind speed, combined with tunnel structural parameters and train operating parameters, the travel distance of the pollutants released by the first locomotive is calculated, including: Determine whether the relative wind speed has reached a stable state; When the relative wind speed reaches a stable state, the calculation formula for the distance the pollutants generated by the first turbine head travels is as follows: ; in, Let v be the distance the pollutant moves relative to the first nose at time t. 差 (t) represents the relative wind speed at time t, q represents the time when the steady state is reached, and p represents the time when the train exits the tunnel. When the relative wind speed has not reached a steady state, the calculation formula for the distance the pollutants generated by the first turbine head travels is as follows: ; Among them, L t Let t be the distance the pollutant moves relative to the first nozzle.

[0008] Furthermore, determining whether the relative wind speed has reached a steady state includes: The formula for calculating the standard deviation of relative wind speed is as follows: (Set up a sliding window of length Y) ; in, v represents the standard deviation of relative wind speed 差 (q) represents the relative wind speed at time q. v within the sliding window 差 The mean of (q), where Y is the length of the sliding window; ; Where H represents the maximum slope between any two adjacent moments within the sliding window. The interval between two adjacent moments; When the standard deviation of the relative wind speed is not greater than the preset standard deviation value, and the maximum value of the slope is not less than the preset slope value, v 差 (q) A steady state is reached, denoted as time q, and the time required to reach the steady state is t. q .

[0009] Furthermore, in S4, based on the travel distance, combined with tunnel structural parameters and train operating parameters, the pollutant concentration at the second locomotive head is assessed, including: The pollutant concentration at the second nose at time j is calculated using the following formula: ; Among them, U j Let t represent the pollutant concentration at the second turbine head at time j, Q represent the pollutant release rate at the first turbine head, and t represent the pollutant concentration at the second turbine head at time j. j Let t be the time corresponding to time j, 0 ≤ t j ≤t p tp L is the time it takes for the train to pass through the tunnel. t F represents the distance the pollutants generated by the first tunnel boring machine traveled, and F represents the cross-sectional area of ​​the tunnel. T Let K be the cross-sectional area of ​​the train, and K be the non-uniformity coefficient.

[0010] Furthermore, in S4, the formula for calculating the updated target wind speed is: ; in, To adjust the target wind speed after the kth iteration, m is the relative wind speed iteration coefficient, and v 差 (q) represents the relative wind speed in a steady state, k represents the number of times the target wind speed is adjusted (k≥1), and r represents the adjustment precision.

[0011] This invention also provides a dual-engine internal combustion engine traction tunnel ventilation speed optimization system, used to execute the above-mentioned dual-engine internal combustion engine traction tunnel ventilation speed optimization method, the system including the following modules: The piston wind speed calculation module is used to calculate the piston wind speed of the train passing through the tunnel at each time step based on the tunnel structure parameters and train operation parameters, and to set the initial target wind speed. Relative wind speed calculation module: Connected to the piston wind speed calculation module, it is used to calculate the relative wind speed of the train at the current moment based on the piston wind speed and target wind speed, combined with tunnel structure parameters and train operation parameters. Pollutant movement distance calculation module: connected to the relative wind speed calculation module, used to calculate the movement distance of pollutants released by the first turbine head based on the relative wind speed, combined with tunnel structure parameters and train operation parameters. If the movement distance is less than the distance between the two turbine heads, the timing control module is called; otherwise, the pollutant concentration assessment module is called. Pollutant concentration assessment module: Connected to the pollutant movement distance calculation module, it is used to assess the pollutant concentration at the second locomotive head based on the movement distance, combined with tunnel structure parameters and train operation parameters. If the pollutant concentration is less than the concentration threshold, the target wind speed remains unchanged; otherwise, the target wind speed is updated. Timing control module: Connected to the pollutant movement distance calculation module and the pollutant concentration assessment module, it is used to determine whether the corresponding target wind speed has been obtained at all times. If not, it adjusts to the next time moment and calls the relative wind speed calculation module based on the updated target wind speed; if yes, it outputs the target wind speed corresponding to each time moment when the train passes through the tunnel. Ventilation module: Connected to the timing control module, it is used to control the ventilation equipment to ventilate the tunnel according to the target wind speed corresponding to each moment.

[0012] The embodiments of the present invention have the following technical effects: This invention dynamically calculates the piston wind speed at preset steps and time intervals, and calculates the relative wind speed based on the piston wind speed and the target wind speed. This allows for accurate calculation of the migration distance of pollutants from the first locomotive to the second locomotive, providing an effective data foundation for calculating the pollutant concentration at the second locomotive. By employing an optimization method that dynamically updates the target wind speed, it minimizes ventilation energy consumption while ensuring that the pollutant concentration at the second locomotive remains below a safe threshold, making it particularly suitable for operations in remote areas with limited power resources. Simultaneously, it ensures timely synchronization between ventilation control and train operation status, eliminating pollution problems in real time and ensuring a sufficient oxygen supply to the second locomotive, thereby guaranteeing the stable operation of the train's traction power system and solving the problem of lag in traditional methods. Furthermore, this technology fills a gap in existing industry standards for real-time environmental control in tunnels for twin-locomotive trains, providing an innovative solution for the safe operation of high-altitude railway lines. Attached Figure Description

[0013] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0014] Figure 1 This is a flowchart of a method for optimizing ventilation wind speed in a tunnel traction system using a dual-head internal combustion engine, provided by an embodiment of the present invention. Figure 2 This is a cross-sectional view of the tunnel entrance / exit equipment provided in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the calculation implementation principle provided in the embodiments of the present invention; Figure 4 This is a schematic diagram of a tunnel ventilation speed optimization system provided by an embodiment of the present invention, which uses a dual-head internal combustion engine.

[0015] Figure label: 1. Tunnel variable frequency fan; 2. Train locomotive; 3. Train carriage; 4. Train first monitoring device; 5. Train second monitoring device. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0017] This invention proposes a method for optimizing ventilation wind speed in tunnels traction by a dual-head internal combustion engine. Figure 1 This is a flowchart of a method for optimizing ventilation wind speed in a tunnel traction system using a dual-head internal combustion engine, provided in an embodiment of the present invention. (See also...) Figure 1 Specifically, it includes: S1. Based on the tunnel structure parameters and train operation parameters, calculate the piston wind speed of the train passing through the tunnel at each time step, and set the initial target wind speed.

[0018] Specifically, the formula for calculating piston wind speed is as follows: ; Among them, v m (t) represents the piston wind speed inside the tunnel at time t, where t represents time, and A, B, and C represent intermediate variables; The formula for calculating intermediate variable A is as follows: ; Among them, K m V represents the piston wind action coefficient. T Indicates the train's speed. V represents the resistance coefficient at the tunnel entrance. n L represents the natural wind speed inside the tunnel. T Let l represent the tunnel length, α represent the blockage ratio, and l T Indicates the length of the train; The formula for calculating intermediate variable B is as follows: ; The formula for calculating the intermediate variable C is as follows: ; in, This represents the resistance coefficient of the tunnel section excluding the annular space.

[0019] Specifically, the formulas for calculating the parameters of the aforementioned intermediate variables are as follows: ; Where N represents the aerodynamic drag coefficient of the train; the formula for calculating N is as follows: ; in, d represents the friction coefficient of airflow in an annular space. h Indicates the equivalent diameter of the annular space; The calculation formula is as follows: ; Where F represents the cross-sectional area of ​​the tunnel, f T Indicates the cross-sectional area of ​​the train; dh The calculation formula is as follows: ; Where S represents the wetted perimeter of the tunnel section, S T This indicates the wetted perimeter of the train cross-section, and 'a' indicates the train width. The calculation formula is as follows: ; in, The friction coefficient represents the airflow resistance along the annular space, and d represents the equivalent diameter of the tunnel. Indicates the resistance coefficient at the tunnel entrance; The calculation formula is as follows: ; in, The resistance coefficient of the tunnel section excluding the annular space.

[0020] In some embodiments, tunnel structural parameters and train operating parameters are obtained. The tunnel structural parameters include a tunnel length of 13042 meters, a tunnel cross-sectional area of ​​32.23 square meters, a wetted perimeter of 21.1 meters, and an equivalent diameter of 6.11 meters. The auxiliary inclined shaft structural parameters include an extension length of 2590 meters, a cross-sectional area of ​​32.23 square meters, and an equivalent diameter of 5.17 meters. Hydrodynamic characteristic parameters include a friction coefficient of 0.02 for the annular space airflow and a local drag coefficient of 0.5 at the tunnel entrance.

[0021] The train's operating parameters include: a length of 500 meters, a width of 3.1 meters, a cross-sectional area of ​​12.6 square meters, and a wetted perimeter of 14.3 meters. The operating speed is 55 km / h (approximately 15.28 m / s), and the tunnel passage time is 853.7 seconds. Calculations yielded a blockage ratio parameter α = 0.391, an equivalent diameter of the annular space of 2.689 meters, and a train aerodynamic drag coefficient of 0.0087.

[0022] Based on the piston effect, a piston wind calculation coefficient K is introduced. m =11.68. Calculations using the above formula show that the intermediate variables A=0.0983, B=-0.0134, and C=0.001155. With a preset time step of 1 second, the piston wind speed is calculated hourly. The results show that after the train starts, the piston wind speed increases over time. At times t=1s, 2s, 3s, ... 854s, the piston wind speed values ​​are 0.097 m / s, 0.194 m / s, 0.289 m / s, ..., 5.11 m / s, respectively. The initial target wind speed is set to 0.

[0023] S2. Based on the current piston wind speed and target wind speed, combined with tunnel structure parameters and train operation parameters, calculate the relative wind speed of the train at the current moment.

[0024] Specifically, the formula for calculating relative wind speed is as follows: ; Among them, v 差 (t) represents the relative wind speed at time t, v 车 v is the train's running speed. m (t) represents the piston wind speed at time t, F represents the tunnel cross-sectional area, and f T v is the cross-sectional area of ​​the train. 目标 The target wind speed is denoted as .

[0025] In some embodiments, the initial target wind speed is 0, and the preset time interval is 1 second. The specific parameters in the above embodiments can be substituted into the relative wind speed calculation formula to obtain the relative wind speed at each time step. The values ​​are 15.20 m / s, 15.11 m / s, 15.01 m / s, ..., 10.19 m / s.

[0026] S3. Based on the relative wind speed, combined with the tunnel structure parameters and train operation parameters, calculate the movement distance of the pollutants released by the first locomotive. If the movement distance is less than the distance between the two locomotives, then execute S5; otherwise, execute S4.

[0027] Specifically, calculating the distance the pollutants released by the first turbine head travels requires first determining whether the relative wind speed has reached a steady state. Determining whether a steady state has been reached involves setting a sliding window of length Y. The standard deviation of the relative wind speed is calculated using the following formula: ; in, v represents the standard deviation of relative wind speed. 差 (q) represents the relative wind speed at time q. v within the sliding window 差 The mean of (q), where Y is the length of the sliding window; ; Where H represents the maximum slope between any two adjacent moments within the sliding window. The interval between two adjacent moments; When the standard deviation of the relative wind speed is not greater than a preset standard deviation value, and the maximum value of the slope is not less than a preset slope value, v 差 (q) A steady state is reached, the corresponding time is denoted as q, and the time required to reach the steady state is . .

[0028] In some embodiments, a sliding window with a length of 20 seconds is provided, wherein v represents the standard deviation of relative wind speed. 差 (q) represents the relative wind speed at time q. v within 20 seconds 差 The mean of (q) is Y, which is the length of the sliding window and takes the value 20.

[0029] H represents the maximum slope between any two adjacent moments within the sliding window. The interval between two adjacent moments is 1 second, here taken as t. The time t represents the train's travel time in the tunnel. p The time is 854 seconds, where the preset standard deviation is 0.01% and the preset slope is -0.001%. The standard deviation is calculated... With slope H, the steady-state condition is satisfied as follows: when time t q At 370s, v 差 (q) reaches stability, i.e., v 差 (q) = 10.19 m / s.

[0030] Specifically, when the relative wind speed reaches a steady state, the calculation formula for the distance the pollutants generated by the first turbine head travels is as follows: ; Among them, L t Let v be the distance the pollutant moves relative to the first nose at time t. 差 (t) represents the relative wind speed at time t, q represents the time when the train reaches a steady state, and p represents the time when the train exits the tunnel.

[0031] When the relative wind speed has not reached a stable state, the calculation formula for the movement distance of pollutants generated by the first turbine head is as follows: ; Among them, L t Let t be the distance the pollutant moves relative to the first nozzle.

[0032] In some embodiments, the train takes 370 seconds to reach a steady state when passing through the tunnel, and 854 seconds to pass through the entire tunnel. Therefore, the relative wind speed can reach a steady state during the tunnel passage. The relative wind speed at each time step is then calculated. The values ​​are 15.20 m / s, 15.11 m / s, 15.01 m / s, ..., 10.19 m / s. Substituting these values ​​into the corresponding formula, the calculated distance the pollutants generated by the first locomotive travel relative to the train when it exits the tunnel is 6459 m. When t = 38 s, the travel distance is 507 m, while the distance between the two locomotives is 500 m. At this point, the pollutant travel distance is greater than the distance between the two locomotives, so step S4 is executed.

[0033] S4. Based on the travel distance, combined with tunnel structure parameters and train operation parameters, assess the pollutant concentration at the second locomotive head. If the pollutant concentration is less than the concentration threshold, the target wind speed remains unchanged; otherwise, update the target wind speed. Specifically, based on the travel distance, and in conjunction with tunnel structural parameters and train operating parameters, the pollutant concentration at the second locomotive head is assessed, including: The pollutant concentration at the second turbine head at time j is calculated using the following formula: ; Among them, U j Let t represent the pollutant concentration at the second turbine head at time j, Q represent the pollutant release rate at the first turbine head, and t represent the pollutant concentration at the second turbine head at time j. j Let t be the time corresponding to time j, 0 ≤ t j ≤t p t p This refers to the time it takes for the train to pass through the tunnel. Let F be the distance the pollutants generated by the first machine head traveled, and F be the cross-sectional area of ​​the tunnel. T Let K be the cross-sectional area of ​​the train, and K be the non-uniformity coefficient.

[0034] In some embodiments, based on the above calculations, when t=38s, the pollutant travels a distance of 507m, which is greater than the distance between the vehicle heads (500m). At this point, the pollutant has spread to the second engine head, where the non-uniformity coefficient K is 1.1, the pollutant release rate Q at the engine head is 3.19g / s, and the concentration threshold is 0.01488 g / m³. 3 According to the pollutant concentration calculation formula, at the 38th second, the pollutant concentration in the environment surrounding the second turbine head is 0.01304 g / m³. 3 At this point, the pollutant concentration is less than the concentration threshold, so the target wind speed remains unchanged. Continuing the calculation to the next moment, at the 119th second, the pollutant concentration at the second turbine head is 0.01490 g / m³. 3 When the concentration exceeds the threshold, v 目标 =0 does not meet environmental requirements. The target wind speed needs to be updated.

[0035] Specifically, the formula for calculating the updated target wind speed is as follows: ; in, To update the target wind speed after the kth iteration, m is the relative wind speed iteration coefficient, and v 差 (q) represents the relative wind speed in a steady state, k represents the number of times the target wind speed is updated, k≥1, and r represents the adjustment precision.

[0036] In some embodiments, the relative wind speed iteration coefficient is taken as... The adjustment precision r is 0.2. During the first adjustment, k is set to 1, and the steady-state relative wind speed is 10.19 m / s. Substituting these values ​​into the above formula, we can obtain v. 目标1 The speed is 1.7 m / s, and the direction is opposite to the direction of the train's travel.

[0037] S5. Determine whether the corresponding target wind speed has been obtained at all times. If not, adjust to the next time and return to execute S2 based on the updated target wind speed. If yes, output the target wind speed corresponding to each time step when the train passes through the tunnel.

[0038] In some embodiments, it is determined whether the corresponding target wind speed has been obtained for all time points. If not, the updated target wind speed is used to continue executing S2 until the corresponding target wind speed is obtained for all time points. This ultimately yields a time-by-time record of the target wind speed as the train passes through the tunnel. Within 0s, 1s, 2s, ..., 118s, the target wind speed is 0, and the operating point of the fan at this time is recorded as G0; within 119s, 120s, ..., 205s, the target wind speed is 1.7m / s, and the operating point of the fan at this time is recorded as G1; within 206s, 207s, ..., 216s, the target wind speed is 1.72m / s, and the operating point of the fan at this time is recorded as G2; within 217s, 218s, ..., 854s, the target wind speed is 1.74m / s, and the operating point of the fan at this time is recorded as G3.

[0039] S6. Control the ventilation equipment to ventilate the tunnel according to the target wind speed corresponding to each time moment; In some embodiments, the criterion for determining when a train enters the tunnel is that when the photoelectric sensor at the tunnel entrance is blocked, the first locomotive of the train is triggered, and the radar detects an object moving towards the tunnel at a speed approaching that of the train. When the signals from the photoelectric sensor and the radar (i.e., the first train monitoring device 4 and the second train monitoring device 5) are simultaneously valid, this is the time when the train enters the tunnel, and all the tunnel variable frequency fans 1 begin to operate under conditions G0, G1, G2, and G3 respectively in the following timeframes: 0s-118s, 119s-205s, 206s-216s, and 217s-854s.

[0040] When the photoelectric sensor at the tunnel exit changes from blocked to unobstructed, meaning the rear of the train has passed, the radar detects that the object is moving away from the tunnel and its speed matches that of the train. Once the photoelectric signal is restored and the radar confirms, the train leaves the tunnel, and all tunnel frequency converter fans 1 are shut down.

[0041] In some embodiments, such as Figure 2 , Figure 3As shown, three sets of three tunnel variable frequency fans 1, totaling nine units, are arranged at the tunnel entrance, middle, and exit. These fans provide the target wind speed and employ a variable frequency design to meet different target wind speed requirements at different times. The target wind speed can be pre-programmed to achieve variable frequency control of the tunnel variable frequency fans 1.

[0042] The train involves two locomotives 2. According to the direction of travel, the locomotive that is in front is the first locomotive and the locomotive that is behind is the second locomotive. Each locomotive 2 will pull a certain number of train carriages 3. Considering the train speed, the first monitoring device 4 of the train is mainly composed of through-beam photoelectric sensors. The models can be Omron E3Z-LS61 series, Keyone LR-X series, etc., and the monitoring distance can meet the tunnel width requirements.

[0043] To verify the monitoring signal of the first train monitoring device 4 and reduce false alarms, a second train monitoring device 5 was also installed. The main body of the device is a millimeter-wave radar, which detects the direction and speed of the train's movement through the Doppler effect. Two devices are installed at the entrance and exit of the tunnel. The entrance radar faces the direction in which the train is coming and covers the track and surrounding area, while the exit radar faces the direction in which the train is leaving.

[0044] Figure 4 This is a schematic diagram of a tunnel ventilation speed optimization system for dual-head internal combustion engine traction provided in an embodiment of the present invention. This system is used to execute the tunnel ventilation speed optimization method for dual-head internal combustion engine traction described in the above embodiment, such as... Figure 4 As shown, the system includes the following modules: The piston wind speed calculation module is used to calculate the piston wind speed of the train passing through the tunnel at each time step based on the tunnel structure parameters and train operation parameters, and to set the initial target wind speed. Relative wind speed calculation module: connected to the piston wind speed calculation module, used to calculate the relative wind speed of the train at the current moment based on the piston wind speed and target wind speed, combined with tunnel structure parameters and train operation parameters; Pollutant movement distance calculation module: connected to the relative wind speed calculation module, used to calculate the movement distance of pollutants released by the first turbine head based on the relative wind speed, combined with tunnel structure parameters and train operation parameters. If the movement distance is less than the distance between the two turbine heads, the timing control module is called; otherwise, the pollutant concentration assessment module is called. Pollutant concentration assessment module: connected to the pollutant movement distance calculation module, used to assess the pollutant concentration at the second locomotive based on the movement distance, combined with tunnel structure parameters and train operation parameters. If the pollutant concentration is less than the concentration threshold, the target wind speed remains unchanged; otherwise, the target wind speed is updated. The timing control module is connected to the pollutant movement distance calculation module and the pollutant concentration assessment module. It is used to determine whether the corresponding target wind speed has been obtained at all times. If not, it adjusts to the next time moment and calls the relative wind speed calculation module based on the updated target wind speed. If yes, it outputs the target wind speed corresponding to each time moment when the train passes through the tunnel. Ventilation module: connected to the timing control module, used to control the ventilation equipment to ventilate the tunnel according to the target wind speed corresponding to each time moment.

[0045] Finally, it should be noted that 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 foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing ventilation wind speed in tunnels traction by a dual-head internal combustion engine, characterized in that, Includes the following steps: S1. Based on the tunnel structure parameters and train operation parameters, calculate the piston wind speed of the train passing through the tunnel at each time step, and set the initial target wind speed. Based on tunnel structural parameters and train operating parameters, the piston wind speed of the train passing through the tunnel is calculated hourly according to a preset time step, including: The formula for calculating piston wind speed is as follows: ； Among them, v m (t) represents the piston wind speed inside the tunnel at time t, where t represents time, and A, B, and C represent intermediate variables; The formula for calculating intermediate variable A is as follows: ； Among them, K m V represents the piston wind action coefficient. T Indicates the train's speed. V represents the resistance coefficient at the tunnel entrance. n L represents the natural wind speed inside the tunnel. T The length of the tunnel is represented by l, α represents the blocking ratio, and l represents the tunnel length. T Indicates the length of the train; The formula for calculating intermediate variable B is as follows: ； The formula for calculating the intermediate variable C is as follows: ； in, This represents the resistance coefficient of the tunnel section excluding the annular space. S2. Based on the current piston wind speed and target wind speed, combined with tunnel structure parameters and train operation parameters, calculate the relative wind speed of the train at the current moment. S3. Based on the relative wind speed, combined with the tunnel structure parameters and train operation parameters, calculate the movement distance of the pollutants released by the first turbine head. If the movement distance is less than the distance between the two turbine heads, then execute S5; otherwise, execute S4. S4. Based on the travel distance, and in conjunction with tunnel structure parameters and train operation parameters, assess the pollutant concentration at the second locomotive head. If the pollutant concentration is less than a concentration threshold, the target wind speed remains unchanged; otherwise, update the target wind speed. Assessing the pollutant concentration at the second locomotive head based on the travel distance, and in conjunction with tunnel structure parameters and train operation parameters, includes: The pollutant concentration at the second turbine head at time j is calculated using the following formula: ； Among them, U j Let t represent the pollutant concentration at the second turbine head at time j, Q represent the pollutant release rate at the first turbine head, and t represent the pollutant concentration at the second turbine head at time j. j Let t be the time corresponding to time j, 0 ≤ t j ≤t p , t p L is the time it takes for the train to pass through the tunnel. t Let F be the distance the pollutants generated by the first machine head traveled, and F be the cross-sectional area of ​​the tunnel. T Where K is the cross-sectional area of ​​the train, and K is the non-uniformity coefficient. The updated formula for calculating the target wind speed is as follows: ； Where, v 目标k To update the target wind speed after the kth iteration, m is the relative wind speed iteration coefficient, and v 差 (q) represents the relative wind speed in a steady state, k represents the number of times the target wind speed is updated, k≥1, and r represents the adjustment precision; S5. Determine whether the corresponding target wind speed has been obtained for all time points. If not, adjust to the next time point and return to execute S2 based on the updated target wind speed. If yes, output the target wind speed corresponding to each time point when the train passes through the tunnel. S6. Control the ventilation equipment to ventilate the tunnel according to the target wind speed corresponding to each time moment; The first engine head is the internal combustion engine located in front of the train in the direction of travel, and the second engine head is the internal combustion engine located behind the train in the direction of travel.

2. The method for optimizing tunnel ventilation speed using a dual-head internal combustion engine according to claim 1, characterized in that, In step S2, the relative wind speed of the train at the current moment is calculated using the following formula: ； Among them, v 差 (t) represents the relative wind speed at time t, v 车 v is the train's running speed. m (t) represents the piston wind speed at time t, F represents the tunnel cross-sectional area, and f T v is the cross-sectional area of ​​the train. 目标 The target wind speed is denoted as .

3. The method for optimizing tunnel ventilation speed using a dual-head internal combustion engine according to claim 2, characterized in that, In step S3, based on the relative wind speed, combined with tunnel structure parameters and train operating parameters, the travel distance of the pollutants released by the first locomotive is calculated, including: Determine whether the relative wind speed has reached a stable state; When the relative wind speed reaches a stable state, the calculation formula for the distance the pollutants generated by the first turbine head travels is as follows: ； in, Let v be the distance the pollutant moves relative to the first nose at time t. 差 (t) represents the relative wind speed at time t, q represents the time when the steady state is reached, and p represents the time when the train exits the tunnel. When the relative wind speed has not reached a stable state, the calculation formula for the movement distance of pollutants generated by the first turbine head is as follows: ； Among them, L t Let t be the distance the pollutant moves relative to the first nozzle.

4. The method for optimizing tunnel ventilation velocity using a dual-head internal combustion engine according to claim 3, characterized in that, Determining whether the relative wind speed has reached a steady state includes: Set a sliding window of length Y, and calculate the standard deviation of the relative wind speed using the following formula: ； in, v represents the standard deviation of relative wind speed. 差 (q) represents the relative wind speed at time q. v within the sliding window 差 The mean of (q), where Y is the length of the sliding window; ； Where H represents the maximum slope between any two adjacent moments within the sliding window. The interval between two adjacent moments; When the standard deviation of the relative wind speed is not greater than a preset standard deviation value, and the maximum value of the slope is not less than a preset slope value, v 差 (q) A steady state is reached, denoted as time q, and the time required to reach the steady state is t. q .

5. A dual-head internal combustion engine traction tunnel ventilation speed optimization system, used to implement the dual-head internal combustion engine traction tunnel ventilation speed optimization method according to any one of claims 1-4, characterized in that, The system includes the following modules: The piston wind speed calculation module is used to calculate the piston wind speed of the train passing through the tunnel at each time step based on the tunnel structure parameters and train operation parameters, and to set the initial target wind speed. Relative wind speed calculation module: connected to the piston wind speed calculation module, used to calculate the relative wind speed of the train at the current moment based on the piston wind speed and target wind speed, combined with tunnel structure parameters and train operation parameters; Pollutant movement distance calculation module: connected to the relative wind speed calculation module, used to calculate the movement distance of pollutants released by the first turbine head based on the relative wind speed, combined with tunnel structure parameters and train operation parameters. If the movement distance is less than the distance between the two turbine heads, the timing control module is called; otherwise, the pollutant concentration assessment module is called. Pollutant concentration assessment module: connected to the pollutant movement distance calculation module, used to assess the pollutant concentration at the second locomotive based on the movement distance, combined with tunnel structure parameters and train operation parameters. If the pollutant concentration is less than the concentration threshold, the target wind speed remains unchanged; otherwise, the target wind speed is updated. The timing control module is connected to the pollutant movement distance calculation module and the pollutant concentration assessment module. It is used to determine whether the corresponding target wind speed has been obtained at all times. If not, it adjusts to the next time moment and calls the relative wind speed calculation module based on the updated target wind speed. If so, output the target wind speed at each moment as the train passes through the tunnel; Ventilation module: connected to the timing control module, used to control the ventilation equipment to ventilate the tunnel according to the target wind speed corresponding to each time moment.

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