A method for optimizing the height of a subway track top air outlet

Abstract

This invention discloses a method for optimizing the setting height of subway track-top vents, relating to the technical field of subway track-top vents, specifically including S1, S2, and S3. The method proposed in this invention can quantitatively calculate the height of the track-top vent under optimal heat dissipation. Simultaneously, the input conditions for the calculation simulation of this invention balance scientific rigor and engineering feasibility. Relying on the regularity of subway operation, it uses time-weighted averaging to determine typical values ​​of piston air temperature and velocity, and typical values ​​of condenser outlet air temperature and velocity. This not only relatively scientifically reflects the boundary conditions themselves but also significantly reduces the computational workload caused by taking data one by one within the boundary condition range, making engineering applications more convenient.

Description

Technical Field

[0001] This invention relates to the field of subway track top ventilation technology, specifically a method for optimizing the setting height of subway track top ventilation openings. Background Technology

[0002] Currently, the track-top ventilation ducts are suspended at the junction of the station's central slab and the structural side walls. The width and height of the track-top ventilation ducts are generally standardized across the entire line, only needing to meet clearance requirements. The track-top ventilation openings are openings at the bottom of the track-top ventilation ducts, therefore their height follows that of the track-top ventilation ducts, only meeting clearance requirements and not considering the differences in heat dissipation efficiency at different heights.

[0003] In addition, because the distance between the rail top vent and the top of the train is too long, some of the heat emitted by the train's condenser is dissipated into the section under the action of piston wind before it can be discharged through the rail top vent; while the distance between the rail top vent and the top of the train is too short, the heat dissipation channel is too narrow, resulting in high resistance, poor airflow organization, and heat cannot be discharged well.

[0004] Therefore, in order to address the above problems, there is an urgent need for a method to optimize the setting height of the subway track top ventilation duct so that the heat dissipation effect of the track top ventilation duct can be maximized. Summary of the Invention

[0005] The purpose of this invention is to provide a method for optimizing the setting height of the subway track top ventilation opening, so as to solve the problems mentioned in the background art.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] This invention provides a method for optimizing the setting height of subway track top ventilation openings, comprising the following steps:

[0008] S1. Computer modeling of the subway station track area, mainly including track area tunnel, track top ventilation duct, and opening at the bottom of track top ventilation duct (i.e., track top ventilation opening). The track top ventilation opening is a plurality of rectangles, and each track top ventilation opening is located directly opposite the top air conditioning condenser when the train stops at the station. The height of the track top ventilation opening is the distance from the track top ventilation opening to the top air conditioning condenser of the train.

[0009] S2. Compile the piston air temperature and velocity of the station track area tunnel under different times and different operating modes, obtain the range of piston air temperature and velocity of the station track area tunnel, and determine the typical values ​​of piston air temperature and velocity; compile the outlet air temperature and velocity of the train air conditioner condenser under different working conditions, obtain the range of condenser outlet air temperature and velocity, and determine the typical values ​​of condenser outlet air temperature and velocity.

[0010] S3. Based on the typical values ​​of piston air temperature and velocity, as well as the typical values ​​of condenser outlet air temperature and velocity, as the boundary conditions for simulation calculation, and combined with other known boundary conditions, the steady-state temperature distribution field of the tunnel under different working conditions is calculated, and the optimal rail top air outlet height is determined.

[0011] Preferably, in step S1: the calculation model selected is the high Reynolds number standard two-equation k-ε model turbulence model suitable for engineering calculation requirements, and the two equations are as follows:

[0012] ;

[0013] Among them, G k G represents the amount of turbulent kinetic energy generated due to the velocity gradient. b Y represents the amount of turbulent kinetic energy generated due to buoyancy. M C represents the effect of fluctuating expansion in a compressible turbulent process on the total turbulent dissipation rate. 1ε C 2ε C 3ε σ is a constant. k and σ ε S represents the Prandtl number of turbulent flow, where k is the turbulent kinetic energy and ε is the turbulent dissipation rate. k and S ε For user-defined source terms, the formula for calculating the turbulent viscosity coefficient is:

[0014] ;

[0015] Where C μ It is a constant.

[0016] Preferably, in step S2: the different times and different operating modes refer to different train departure intervals and different time periods, and the different working states of the condenser refer to various cooling modes of the train air conditioner. In order to more accurately express the actual meaning of the typical value, the typical value does not take the intermediate value within the temperature and speed range, but takes the time-weighted average value.

[0017] Preferably, in step S3: the initial boundary conditions for the simulation calculation mainly include the wind speed and temperature at the tunnel entrance of the track area, the air temperature and speed at the train condenser outlet, the soil temperature outside the tunnel, and the exhaust speed of the air vent at the top of the track.

[0018] Preferably, in step S3: when the train stops at the station, the temperature in the tunnel of the track area shows a steady-state distribution with the highest temperature on the train's condenser and the temperature gradually decreasing around it. Selecting the temperature distribution of the longitudinal section passing through the train's centerline best reflects the characteristics of the research object.

[0019] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects:

[0020] 1. By using the method proposed in this invention to optimize the setting height of the subway rail top air vent, the height of the rail top air vent under the best heat dissipation effect can be quantitatively calculated;

[0021] 2. The input conditions for the computational simulation of this invention take into account both scientific rigor and engineering feasibility. Based on the regularity of subway operation, the typical values ​​of piston air temperature and velocity, and the typical values ​​of condenser outlet air temperature and velocity are determined by time-weighted averaging. This not only reflects the boundary conditions themselves in a relatively scientific way, but also greatly reduces the amount of calculation caused by taking data one by one within the boundary conditions range, making engineering applications more convenient. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0023] Figure 1 This is a schematic diagram showing the height of the air vent at the top of the rail in this invention;

[0024] Figure 2 This is a schematic diagram of the boundary condition being piston air temperature in this invention;

[0025] Figure 3 This is a schematic diagram of the boundary condition being piston wind speed in this invention;

[0026] Figure 4 This is a schematic diagram of the boundary condition being the condenser outlet air temperature in this invention;

[0027] Figure 5 This is a schematic diagram of the boundary condition being the condenser outlet air velocity in this invention;

[0028] In the picture:

[0029] 1. Rail top ventilation duct; 2. Rail top ventilation opening; 3. Height of rail top ventilation opening; 4. Civil engineering clearance; 5. Vehicle clearance. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0031] A method for optimizing the setting height of subway track top ventilation openings includes the following steps:

[0032] S1. Computer modeling of the subway station track area, mainly including track area tunnel, track top ventilation duct 1, and opening at the bottom of track top ventilation duct 1 (i.e., track top ventilation opening 2). The track top ventilation opening 2 is a plurality of rectangles, and each track top ventilation opening 2 is positioned directly opposite the top air conditioning condenser when the train stops at the station. The height 3 of the track top ventilation opening is the distance from the track top ventilation opening 2 to the top air conditioning condenser of the train.

[0033] Specifically, the computational model selected is the high Reynolds number standard two-equation k-ε turbulence model, which is suitable for engineering calculation requirements. The two equations are as follows:

[0034] ;

[0035] Among them, G k G represents the amount of turbulent kinetic energy generated due to the velocity gradient. b Y represents the amount of turbulent kinetic energy generated due to buoyancy. M C represents the effect of fluctuating expansion in a compressible turbulent process on the total turbulent dissipation rate. 1ε C 2ε C 3ε σ is a constant. k and σ ε S represents the Prandtl number of turbulent flow, where k is the turbulent kinetic energy and ε is the turbulent dissipation rate. k and S ε For user-defined source terms, the formula for calculating the turbulent viscosity coefficient is:

[0036] ;

[0037] Where C μ It is a constant.

[0038] Based on the model characteristics, the values ​​of each constant are as follows:

[0039] C1 ε =1.44, C2 ε =1.92, C μ =0.09, σ k =1,σ ε =1.3.

[0040] S2. Compile the piston air temperature and velocity of the station track area tunnel under different times and different operating modes, obtain the range of piston air temperature and velocity of the station track area tunnel, and determine the typical values ​​of piston air temperature and velocity; compile the outlet air temperature and velocity of the train air conditioner condenser under different working conditions, obtain the range of condenser outlet air temperature and velocity, and determine the typical values ​​of condenser outlet air temperature and velocity.

[0041] Specifically, based on the operating hours from 6:00 AM to 11:00 PM, the piston fan temperature ranged from 26.1℃ to 34.8℃. A typical value of 30.9℃ was obtained by weighting the piston fan temperature by usage time for each period. Figure 2 As shown;

[0042] Based on the piston wind speed range of 2.4 m / s to 6.2 m / s during various operating hours from 6:00 AM to 11:00 PM, a typical value of 4.1 m / s was obtained by weighting the piston wind speed for each time period. Figure 3 As shown;

[0043] Based on the condenser's operating status from 6:00 AM to 11:00 PM, the condenser outlet air temperature ranged from 42.2℃ to 49.4℃. A typical value of 46.1℃ was obtained by weighting the condenser outlet air temperature over time for each period. Figure 4 As shown;

[0044] Based on the condenser's operating status from 6:00 AM to 11:00 PM, the condenser outlet air velocity ranged from 6.4 m / s to 7.8 m / s. A time-weighted calculation of the condenser outlet air velocity for each time period yielded a typical value of 6.9 m / s. Figure 5 As shown.

[0045] S3. Based on the typical values ​​of piston air temperature and velocity and the typical values ​​of condenser outlet air temperature and velocity, the boundary conditions for simulation calculation are used. Combined with other known boundary conditions, the temperature distribution field of the tunnel in the track area under different working conditions is calculated, and the optimal height of the rail top air outlet is determined.

[0046] Specifically, the initial boundary conditions are as follows:

[0047] The piston wind speed at the tunnel entrance is 4.1 m / s, as obtained in step S2.

[0048] The piston air temperature at the tunnel entrance is 30.9℃, as obtained in step S2.

[0049] The condenser outlet air velocity is 6.9 m / s, as obtained in step S2;

[0050] The condenser outlet air temperature is 46.1℃, as obtained in step S2;

[0051] As shown in the attached diagram, there are five 0.5m air vents at the top of the rail. 2 One set, a total of 12 sets, with a fan air volume of 40m³ / h. 3 / s, since the air vents use adjustable gate valves, under ideal conditions, after debugging, the flow rate of each air vent is the same. However, since the valve opening is affected by factors such as the internal civil engineering structure of the rail top air duct and is not uniform, and has little impact on the calculation, it is assumed that the air passage area of ​​rail top air vent 2 is equal to the air vent area to meet the engineering calculation requirements. The wind speed of each air vent is calculated to be 1.33m / s, and the flow rate is 0.67 m3 / s, both of which are constant values.

[0052] The tunnel exit is designed as a pure pressure exit with no restrictions on speed or temperature.

[0053] Based on the above conditions, the steady-state calculation of the k-ε model was completed, the temperature distribution of the longitudinal section passing through the train centerline was obtained, and the average temperature of the tunnel was then calculated.

[0054] The average tunnel temperature at various heights of the track top ventilation opening is as follows:

[0055]

[0056] As shown in the table above, the height h of the vent at the top of the track has a significant impact on heat dissipation. When h is set to 0.8m, the average temperature of the tunnel in the track area is the lowest, indicating that the heat dissipation effect is optimal.

[0057] Preferably, in step S2: the different times and different operating modes refer to different train departure intervals and different time periods, and the different working states of the condenser refer to various cooling modes of the train air conditioner. In order to more accurately express the actual meaning of the typical value, the typical value does not take the intermediate value within the temperature and speed range, but takes the time-weighted average value.

[0058] Preferably, in step S3: the initial boundary conditions for the simulation calculation mainly include the wind speed and temperature at the tunnel entrance of the track area, the air temperature and speed at the train condenser outlet, the soil temperature outside the tunnel, and the exhaust speed of the track top vent 2.

[0059] Preferably, in step S3: when the train stops at the station, the temperature in the tunnel of the track area shows a steady-state distribution with the highest temperature on the train's condenser and the temperature gradually decreasing around it. Selecting the temperature distribution of the longitudinal section passing through the train's centerline best reflects the characteristics of the research object.

[0060] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for optimizing the setting height of ventilation openings on the top of subway tracks, characterized in that, Includes the following steps: S1. Computer modeling of the subway station track area, mainly including track area tunnel, track top ventilation duct, and opening at the bottom of track top ventilation duct. The track top ventilation opening is a plurality of rectangles, and each track top ventilation opening is located directly opposite the top air conditioning condenser when the train stops at the station. The height of the track top ventilation opening is the distance from the track top ventilation opening to the top air conditioning condenser of the train. S2. Compile the piston air temperature and velocity of the station track area tunnel under different times and different operating modes, obtain the range of piston air temperature and velocity of the station track area tunnel, and determine the typical values ​​of piston air temperature and velocity; compile the outlet air temperature and velocity of the train air conditioner condenser under different working conditions, obtain the range of condenser outlet air temperature and velocity, and determine the typical values ​​of condenser outlet air temperature and velocity. S3. Based on the typical values ​​of piston air temperature and velocity and the typical values ​​of condenser outlet air temperature and velocity, the boundary conditions for simulation calculation are used. Combined with other known boundary conditions, the temperature distribution field of the tunnel in the track area under different working conditions is calculated, and the optimal height of the rail top air outlet is determined. In step S2: the different times and different operating modes refer to the different departure intervals and different time periods of the train, and the different working states of the condenser refer to the various cooling modes of the train air conditioner. In order to more accurately express the actual meaning of the typical value, the typical value does not take the intermediate value within the temperature and speed range, but takes the time-weighted average value.

2. The method for optimizing the setting height of the subway track top ventilation opening according to claim 1, characterized in that: In step S1: The calculation model selected is the high Reynolds number standard two-equation k-ε turbulence model, which is suitable for engineering calculation requirements. The two equations are as follows: ； Among them, G k G represents the amount of turbulent kinetic energy generated due to the velocity gradient. b Y represents the amount of turbulent kinetic energy generated due to buoyancy. M C represents the effect of fluctuating expansion in a compressible turbulent process on the total turbulent dissipation rate. 1ε C 2ε C 3ε σ is a constant. k and σ ε S represents the Prandtl number of turbulent flow, where k is the turbulent kinetic energy and ε is the turbulent dissipation rate. k and S ε For user-defined source terms, the formula for calculating the turbulent viscosity coefficient is: ； Where C μ It is a constant.

3. The method for optimizing the setting height of the subway track top ventilation opening according to claim 1, characterized in that: In step S3: the initial boundary conditions for the simulation calculation mainly include the wind speed and temperature at the tunnel entrance of the track area, the air temperature and speed at the train condenser outlet, the soil temperature outside the tunnel, and the exhaust speed at the rail top vent.

4. The method for optimizing the setting height of the subway track top ventilation opening according to claim 3, characterized in that: In step S3: When the train stops at the station, the temperature in the tunnel of the track area shows a steady-state distribution with the highest temperature on the train condenser and the temperature gradually decreasing in the surrounding area. The temperature distribution of the longitudinal section passing through the center line of the train best reflects the characteristics of the research object.

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