Numerical simulation method and device for shield tunneling machine with air-mud-water double-flow field coupling

Abstract

The invention relates to a numerical simulation method and device for an air-muddy-water double-flow-field coupled shield tunneling machine. The method comprises the following steps: discretizing a fluid control equation of air muddy water through a finite volume method, carrying out grid division by adopting an unstructured grid, carrying out spatial discretization by using a second-order windward format, and simulating an unsteady-state wall-attached surface jet flow numerical value; discretizing a solid heat transfer equation of the air muddy water through a finite element method, performing grid division by adopting a tetrahedron unit, and simulating an unsteady state heat transfer numerical value; coupling an unsteady-state wall-attached jet flow numerical value and a simulated unsteady-state heat transfer numerical value in a boundary condition transmission mode, and establishing an air-mud-water double-flow field coupling model; and finally, based on the air muddy water double-flow field coupling model and the physical model of the shield tunneling machine, simulating and calculating the temperature values of the cutterhead and the shell of the shield tunneling machine. The novel coupling method is adopted, the influence of muddy water convection heat exchange is considered, the accuracy of temperature field simulation is improved, and generalization is high.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction simulation, and in particular to a shield machine numerical simulation method and device for air-mud-water dual flow field coupling. Background Art

[0002] With the acceleration of urbanization, the surface space is becoming increasingly scarce, and the development of underground space has gradually received attention. Due to its safety and efficiency, shield machines are widely used in underground projects such as tunnel excavation. However, during the tunneling process of the shield machine, due to factors such as high temperature of the equipment, closed environment and groundwater infiltration, a high temperature and high humidity working environment is formed. This harsh environment not only threatens the health of the operators, but also accelerates the aging of the equipment and increases the risk of shield machine failure. Therefore, accurately grasping the temperature field and velocity field inside the shield machine is of great significance to improving the working environment and ensuring the stable operation of the equipment.

[0003] At present, there are two main methods for analyzing the temperature field of shield machines: First, the ventilation system of the shield machine is designed by comparing the ventilation volume of the shield machine, the number of people working in the shield machine, and the return air speed, and based on the empirical formula, the environmental heat dissipation and the heat generation of each heat source are gradually calculated to determine the thermal balance condition, and the overall temperature distribution is estimated by the finite element algorithm. However, the temperature field data obtained by the finite element method is usually limited by the measured data, and the generalization is poor. It is impossible to calculate the heat generation and dissipation caused by the operation of the equipment and the change of working conditions under different geological conditions. Therefore, static thermal balance calculation alone will produce non-negligible errors. Second, through the data-driven method, a large amount of field engineering data is collected, and a machine learning model such as a multi-layer perceptron model is established to predict the temperature of the shield machine. However, the data-driven method requires a large amount of field data for training, which usually means high sensor deployment and testing costs, and the accuracy of its prediction results is also limited by the sensor location and test conditions.

[0004] Therefore, it is urgent to invent a numerical simulation method that combines the complex heat transfer process of the shield machine and can accurately calculate its temperature field, so as to provide a new technical means for the multi-dimensional coordinated dynamic control of the thermal environment of the shield tunnel. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a shield machine numerical simulation method and device with air-mud-water dual flow field coupling.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A shield machine numerical simulation method for air-mud-water dual flow field coupling includes the following steps:

[0008] The fluid control equations of air-slurry are discretized by finite volume method, meshed by unstructured grids, and spatially discretized by second-order upwind scheme to simulate the numerical value of unsteady wall-attached jet.

[0009] The solid heat transfer equation of air-slurry is discretized by finite element method, and the mesh is divided by tetrahedral units to simulate the unsteady heat transfer numerical value.

[0010] The air-mud-water dual flow field coupling model is established by coupling the unsteady wall jet numerical value and the simulated unsteady heat transfer numerical value through boundary condition transfer.

[0011] Finally, based on the air-mud-water dual flow field coupling model and the physical model of the shield machine, the temperature values ​​of the cutter head and shell of the shield machine are simulated and calculated.

[0012] Furthermore, the physical model of the shield machine includes a vent, a face, a cutter head, a shell and a screw conveyor, and the boundaries of each structure of the shield machine are divided. The boundary layers of the vent, the face and the surface of each structure are divided using an encrypted grid, and the first layer height of the boundary layer grid is X mm.

[0013] Furthermore, the air-mud-water dual flow field coupling model includes the energy conservation equation in the mud-water compartment, the heat conduction equation in the tool changing compartment, the heat flux density in the tunnel, the convective heat transfer in the tunnel, the heat load of the new and old air in the tunnel, and the radiation absorption coefficient of the heat source surface in the tunnel.

[0014] Furthermore, the calculation expression of the heat control equation in the mud water tank is:

[0015]

[0016] Where: is the change in heat of mud water in the mud water tank, h s S c |T c -T s |For the convection heat exchange between mud water and cutter disc, The heat load of the interaction between new and old mud water is is the heat conduction within the mud water itself; s is the density of muddy water, in kg / m 3 ;c s is the specific heat of mud water, in kJ / kg·K; h s is the convective heat transfer coefficient of mud water, in kW / m 2 ·K;S c is the mask of the knife disc, in m 2 ; is the mass flow rate of muddy water, in kg / s; S sis the diameter of the mud and water pipe, in m 2 ; V s is the volume of mud and water in the excavation chamber, in m 3 ,q s is the heat flux density of mud water, in kW / m 2 .

[0017] Furthermore, the calculation expression of the temperature control equation in the tool changing cabin is:

[0018]

[0019] Where: T rc is the initial temperature of the tool changing cabin; ρ a is the density of air, in kg / m 3 ;c a is the specific heat of air, in kJ / kg·K; V rc is the volume of the air in the tool change chamber, in m 3 ; we is the wall thickness of the mud and water tank, in m; S rc is the area of ​​the tunnel face, in m 2 ; S we is the area of ​​the mud tank, in m 2 ;h rc is the convective heat transfer coefficient in the tool change cabin, in kW / m 2 ·K.

[0020] Furthermore, the calculation expression of the heat flux density q in the tunnel is:

[0021]

[0022] Where: q is the heat flux density of the heat source, in kW / m 2 , u is the speed in the tunnel, T is the experimental temperature of the heat source surface, the unit is ℃, is the dimensionless distance of turbulence near the wall; T a is the air temperature.

[0023] Furthermore, the convection heat transfer Q in the tunnel cn The calculation expression is:

[0024]

[0025] Where: represents the convective heat transfer coefficient on the surface of heat source j, S j represents the equivalent area of ​​heat source j.

[0026] Furthermore, the heat load Q of the new and old air in the tunnel in The calculation expression is:

[0027]

[0028] Where: is the mass flow rate of ventilation, in kg / s; c a is the specific heat of air, in kJ / kg·K; T in It is the ventilation wind temperature in °C.

[0029] Furthermore, the calculation expression of the radiation absorption coefficient of the heat source surface in the tunnel is:

[0030]

[0031] Where: α i,j is the value of the radiation energy emitted from the i surface and absorbed by the j surface, F i,j is the shape factor of the heat source surface.

[0032] The present invention also provides a numerical simulation device for a shield machine with dual flow fields of air and mud and water coupled, comprising a memory, a processor, an input-output device and a display device, as well as a numerical simulation program, parameter settings and calculation results stored in the memory. When the processor executes the program, a numerical simulation method for a shield machine with dual flow fields of air and mud and water coupled as described above is implemented. The input-output device is used to receive parameter settings input by a user, and the display device is used to display calculation results.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1) The present invention simulates the non-steady-state wall-mounted jet value through the air field heat transfer mechanism model, simulates the non-steady-state heat transfer value through the mud-water field heat transfer mechanism model, couples the non-steady-state wall-mounted jet value and the non-steady-state heat transfer value, establishes an air-mud-water dual flow field coupling model, realizes the simulation calculation of the operating temperature of each component of the shield machine, accurately reflects the coupling effect of the influence of air and mud-water on the temperature of the shield machine during the flow process, and the simulation result is more accurate.

[0035] 2) The present invention takes into account the complex heat transfer process inside the shield machine based on the heat conduction mechanism of the shield machine, including the flow of air and mud water, convection heat transfer, radiation heat transfer, etc., and can consider the influence of different geological conditions and operating conditions on the temperature field. It has better generalization and solves the problem of being unable to comprehensively analyze the temperature field of the shield machine and the unclear heat conduction relationship under a complex thermal environment; it provides an accurate, comprehensive and highly generalized analysis method for the temperature transfer, temperature field distribution and flow field turbulence distribution of the shield machine.

[0036] 3) The present invention provides an accurate, comprehensive and highly generalizable analysis method for the temperature transfer, temperature field distribution and flow field turbulence distribution of a shield machine. This method can be applied to the simulation of the temperature field of a shield machine under different geological conditions.

[0037] 4) The present invention can be applied in the design stage of a shield machine to optimize the ventilation system and the cooling system; it can be applied in the construction stage of a shield machine to predict the operating status of the shield machine and guide the construction of the shield machine; it can be applied in the operation and maintenance stage of a shield machine to monitor the temperature of the shield machine and predict the risk of failure, thereby improving the safety of the operation of the shield machine and reducing the energy consumption of the operation of the shield machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the method of the present invention.

[0039] Figure 2 This is the temperature cloud map when the shield machine is started.

[0040] Figure 3 This is the temperature cloud map when the shield machine is shut down.

[0041] Figure 4 It is a 3D velocity field trajectory cloud map. DETAILED DESCRIPTION

[0042] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0043] Example 1

[0044] This embodiment simulates the heat transfer process of the shield machine based on the simulation software CFD.

[0045] The present invention provides a shield machine numerical simulation method for air-mud-water dual flow field coupling, comprising the following steps:

[0046] Determine the physical parameters of air, mud and water, and the physical structural parameters of the shield machine, such as measuring the air temperature through a thermistor and measuring the air specific heat through a specific heat capacity meter, and measuring the air density to be 1.225kg / m^3…;

[0047] The heat transfer mechanism model of air field is established according to the physical parameters of air, the heat transfer mechanism model of mud-water field is established according to the physical parameters of mud-water, and the physical model of shield machine is established according to the physical structure parameters of shield machine;

[0048] The unsteady wall jet numerical simulation is carried out through the air field heat transfer mechanism model, and the unsteady heat transfer numerical simulation is carried out through the mud water field heat transfer mechanism model;

[0049] The air-mud-water dual flow field coupling model is established by coupling the unsteady wall jet numerical value and the simulated unsteady heat transfer numerical value through boundary condition transfer.

[0050] Based on the air-mud-water dual flow field coupling model and the physical model of the shield machine, the temperature value of the shield machine is simulated and calculated.

[0051] The specific implementation process is:

[0052] The physical model of the shield machine includes structures such as the excavation chamber, the tool change chamber, the segment assembly machine, the ventilation pipe, the mud and water pipe, the transformer, the PLC, the container, the control room, the mud pump, etc. The boundaries of each structure of the shield machine are divided, and the heat transfer surface grid is divided in the boundary layer of the ventilation opening, the tunnel face and the surface of each structure. In the CFD software used in this embodiment, the mesh format file is output to record the physical model of the shield machine.

[0053] The S2S radiation model is used to calculate the long-wave radiation coefficient in the air field, and the software is used to calculate the shape factor of each heat source surface. The air in the tunnel is regarded as an incompressible fluid, and the convection heat transfer coefficient and boundary conditions of each heat source surface are set to establish the air field heat transfer mechanism model.

[0054] According to the density, specific heat capacity, thermal conductivity and viscosity of muddy water, the air field heat transfer mechanism model is established through the energy conservation equation;

[0055] The fluid simulation software package Ansys Fluent is used as a solver to solve the multi-physics field coupling of the model. + The UDF function is used to couple the heat transfer between the air field and the mud-water field. The UDF function can use the temperature of the air side as the boundary condition of the mud-water measurement and transfer the heat flux density of the mud-water side to the air side.

[0056] During the forced heat exchange process of the tunnel ventilation system, the temperature change inside the shield machine satisfies the coupling of the dual flow field model, including the following calculation formula:

[0057] (1) The heat control equation in the mud tank is:

[0058]

[0059] Where: is the change in heat of mud water in the mud water tank, h s S c |T c -T s |For the convection heat exchange between mud water and cutter disc, The heat load of the interaction between new and old mud water is is the heat conduction within the mud water itself;s is the density of muddy water, in kg / m 3 ;c s is the specific heat of mud water, in kJ / kg·K; h s is the convective heat transfer coefficient of mud water, in kW / m 2 ·K;S c is the mask of the knife disc, in m 2 ; is the mass flow rate of muddy water, in kg / s; S s is the diameter of the mud and water pipe, in m 2 ; V s is the volume of mud and water in the excavation chamber, in m 3 ,q s is the heat flux density of mud water, in kW / m 2 ;

[0060] (2) Mud water temperature T s The outward transfer process corresponds to the multilayer plate heat transfer physical model, and the corresponding control equation is:

[0061]

[0062] Where: i = 1, 2, 3, i = 1 is the wall of the excavation chamber, i = 2 is the tool change chamber, i = 3 is the pressure wall; ρ i is the density of layer i, kg / m 3 ;c i is the specific heat of layer i in kJ / kg·K; λ i is the thermal conductivity of layer i, W / m·K; T i is the temperature of layer i W / m·K; Q i Internal heat source W / m 3 ;

[0063] Ensure the continuity of heat flow in each layer through the mud water temperature T s The heat transferred out is:

[0064]

[0065] Where T pr is the temperature of the pressure wall, h a is the convective heat transfer coefficient in the tunnel, kW / m2·K; Tin is the wind temperature of the duct ventilation, °C; Δx 3 is the total thickness m; λ pr is the thermal conductivity of the pressure wall, W / m·K;

[0066] The temperature control equation in the tool changing cabin is:

[0067]

[0068] Where: T rc is the initial temperature of the tool changing cabin; ρ a is the density of air, in kg / m 3 ;c a is the specific heat of air, in kJ / kg·K; V rc is the volume of the air in the tool change chamber, in m 3 ; we is the wall thickness of the mud and water tank, in m; S rc is the area of ​​the tunnel face, in m 2 ; S we is the area of ​​the mud tank, in m 2 ;h rc is the convective heat transfer coefficient in the tool change cabin, in kW / m 2 K;

[0069] (3) Heat flux density q in the tunnel:

[0070]

[0071] Where: q is the heat flux density of the heat source, in kW / m 2 , u is the speed in the tunnel, T is the experimental temperature of the heat source surface, the unit is ℃, is the dimensionless distance of turbulence near the wall, T a is the air temperature;

[0072] (4) Convective heat transfer in the tunnel Q cn :

[0073]

[0074] Where: represents the convective heat transfer coefficient on the surface of heat source j, S j represents the equivalent area of ​​heat source j;

[0075] (5) Heat load Q of new and old air in the tunnel in :

[0076]

[0077] Where: is the mass flow rate of ventilation, in kg / s; c a is the specific heat of air, in kJ / kg·K; T in is the ventilation wind temperature, in °C;

[0078] (6) The radiation absorption coefficient of the heat source surface in the tunnel is:

[0079]

[0080] Where: α i,j is the value of the radiation energy emitted from the i surface and absorbed by the j surface, F i,j is the shape factor of the heat source surface;

[0081] The total radiation between the heat source surfaces in the tunnel is:

[0082]

[0083] Where: α j,k is the value of radiation emitted from the j surface and absorbed by the k surface, β j,k is the radiation heat transfer coefficient; T j Expressed as the temperature of the heat source surface in °C;

[0084] Solve the model, set the time step according to the tunneling cycle of the shield machine, and simulate the temperature field of the shield machine with dual flow field coupling;

[0085] (7) According to the energy balance, the temperature in the shield tunnel is T a The control equation is:

[0086]

[0087] Where: V a is the air volume in the tunnel m 3 ; S pr is the area of ​​the pressure wall m 2 ;h pr is the convective heat transfer coefficient of the pressure wall W / m 2 ℃; Q ins (t) is the heat load W of surrounding rock and workers in the tunnel;

[0088] (8) is the coupling factor, and the mud-water-ventilation dual flow field coupling formula is:

[0089]

[0090] Where:

[0091]

[0092] The tunnel consists of three areas. The initial area is the jet flow area, which is characterized by high-speed airflow spraying from the ventilation port to the working face. Due to the entrainment effect of the high-speed jet, the surrounding air is continuously sucked into the jet within a specific range, causing the jet area to continue to increase. Subsequently, the airflow impacts the working face. Due to the limitations of the shield pressure wall and the segment assembly machine, a counterflow zone is formed on the other side of the ventilation duct, and the flow rate in the counterflow zone is much lower than that in the jet flow zone. In the process of flowing to the exit, the combined action of the reverse flow and the jet flow causes an air vortex to form between the equipment, forming a vortex zone. The data is post-processed to generate intuitive temperature cloud maps and velocity cloud maps, Figure 2 This is the temperature cloud diagram when the shield machine is turned on. Figure 3 This is the temperature cloud diagram when the shield machine is shut down. Figure 4 The 3D velocity field trace cloud diagram. The numerical simulation method of the mud-water and air dual flow field coupling proposed in this invention takes the monitored temperature of the equipment and environment in the tunnel as the dynamic boundary condition based on the heat transfer mechanism between the mud-water and air fields. Through numerical simulation, the overall heat transfer process of the shield machine, the heat distribution in the tunnel and the air flow state are supplemented.

[0093] The present invention combines numerical simulation software and mechanism UDF to construct a shield machine engineering tunnel mud-water-air dual flow field coupled multi-physics field model suitable for different geological conditions, ventilation conditions and excavation conditions. It can more accurately simulate the complex heat transfer process inside the shield machine, including the flow of air and mud-water, convection heat transfer, radiation heat transfer, etc., and can consider the influence of different geological conditions and working conditions on the temperature field, and has better generalization.

[0094] Example 2

[0095] Based on Example 1, this embodiment provides a shield machine numerical simulation device for air-mud-water dual flow field coupling, the device comprising a memory, a processor, an input-output device and a display device, as well as a numerical simulation program, parameter settings and calculation results stored in the memory; when the processor executes the program, the parameter settings are read through a data reading module, a calculation grid is generated through a grid generation module, Ansys Fluent is controlled to perform calculations through a solver call module, and dual flow field coupling heat transfer simulation is implemented through a UDF module, and finally, a temperature cloud map, a velocity cloud map and other visual results are generated through a post-processing module, and quantitative data such as the maximum temperature, the minimum temperature of each component of the shield machine, the average temperature of the air in the tunnel, and the maximum temperature are calculated, thereby realizing a shield machine numerical simulation method for air-mud-water dual flow field coupling; the input-output device is used to receive parameter settings input by a user, such as geometric parameters, physical parameters, boundary conditions, etc. of the shield machine; the display device is used to display calculation results, such as temperature cloud maps, velocity cloud maps, quantitative data, etc.

[0096] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A numerical simulation method for shield machine with air-mud-water dual flow field coupling, characterized in that: The following steps are involved: The fluid control equations of air-slurry are discretized by finite volume method, meshed by unstructured grids, and spatially discretized by second-order upwind scheme to simulate the numerical value of unsteady wall-attached jet. The solid heat transfer equation of air-slurry is discretized by finite element method, and the mesh is divided by tetrahedral units to simulate the unsteady heat transfer numerical value. The air-mud-water dual flow field coupling model is established by coupling the unsteady wall jet numerical value and the simulated unsteady heat transfer numerical value through boundary condition transfer. Finally, based on the air-mud-water dual flow field coupling model and the physical model of the shield machine, the temperature values ​​of the cutter head and shell of the shield machine are simulated and calculated.

2. The method for numerical simulation of shield machine with air-mud-water dual flow field coupling according to claim 1 is characterized in that: The physical model of the shield machine includes a vent, a tunnel face, a cutter head, a shell and a screw conveyor. The boundaries of the various structures of the shield machine are divided. The boundary layers of the vent, the tunnel face and the surfaces of the various structures are divided using encrypted grids, and the first layer height of the boundary layer grid is X mm.

3. The method for numerical simulation of shield machine with air-mud-water dual flow field coupling according to claim 1 is characterized in that: The air-mud-water dual flow field coupling model includes the energy conservation equation in the mud-water cabin, the heat conduction equation in the tool change cabin, the heat flux density in the tunnel, the convection heat transfer in the tunnel, the heat load of the new and old air in the tunnel, and the radiation absorption coefficient of the heat source surface in the tunnel.

4. The method for numerical simulation of shield machine with air-mud-water dual flow field coupling according to claim 3 is characterized in that: The calculation expression of the heat control equation in the mud water tank is: Where: is the change in heat of mud water in the mud water tank, h s S c |T c -T s |For the convection heat exchange between mud water and cutter disc, The heat load of the interaction between new and old mud water is is the heat conduction within the mud water itself; s is the density of muddy water, in kg / m 3 ;c s is the specific heat of mud water, in kJ / kg·K; h s is the convective heat transfer coefficient of mud water, in kW / m 2 ·K;S c is the mask of the knife disc, in m 2 ; is the mass flow rate of muddy water, in kg / s; S s is the diameter of the mud and water pipe, in m 2 ; V s is the volume of mud and water in the excavation chamber, in m 3 ,q s is the heat flux density of mud water, in kW / m 2 .

5. The method for numerical simulation of shield machine with air-mud-water dual flow field coupling according to claim 3 is characterized in that: The calculation expression of the temperature control equation in the tool changing cabin is: Where: T rc is the initial temperature of the tool changing cabin; ρ a is the density of air, in kg / m 3 ;c a is the specific heat of air, in kJ / kg·K; V rc is the volume of the air in the tool change chamber, in m 3 ; λ we is the wall thickness of the mud and water tank, in m; S rc is the area of ​​the tunnel face, in m 2 ; S we is the area of ​​the mud tank, in m 2 ; h rc is the convective heat transfer coefficient in the tool change cabin, in kW / m 2 ·K.

6. The method for numerical simulation of shield machine with air-mud-water dual flow field coupling according to claim 3 is characterized in that: The calculation expression of the heat flux density q in the tunnel is: Where: q is the heat flux density of the heat source, in kW / m 2 , u is the speed in the tunnel, T is the experimental temperature of the heat source surface, the unit is ℃, is the dimensionless distance of turbulence near the wall; T a is the air temperature.

7. The method for numerical simulation of shield machine with air-mud-water dual flow field coupling according to claim 3 is characterized in that: The convection heat transfer in the tunnel Q cn The calculation expression is: Where: represents the convective heat transfer coefficient on the surface of heat source j, S j represents the equivalent area of ​​heat source j.

8. The method for numerical simulation of shield machine with air-mud-water dual flow field coupling according to claim 3 is characterized in that: The heat load Q of the new and old air in the tunnel in The calculation expression is: Where: is the mass flow rate of ventilation, in kg / s; c a is the specific heat of air, in kJ / kg·K; T in It is the ventilation wind temperature in °C.

9. The method for numerical simulation of shield machine with air-mud-water dual flow field coupling according to claim 3 is characterized in that: The calculation expression of the radiation absorption coefficient of the heat source surface in the tunnel is: Where: α i,j is the value of the radiation energy emitted from the i surface and absorbed by the j surface, F i,j is the shape factor of the heat source surface.

10. A shield machine numerical simulation device with air-mud-water dual flow field coupling, comprising a memory, a processor, an input-output device and a display device, as well as a numerical simulation program, parameter settings and calculation results stored in the memory, characterized in that: When the processor executes the program, it implements a shield machine numerical simulation method for air-mud-water dual flow field coupling as described in any one of claims 1-9, the input and output devices are used to receive parameter settings input by the user, and the display device is used to display calculation results.

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