Slurry shield cutterhead nozzle arrangement method and system

Abstract

The invention discloses a slurry shield cutterhead nozzle arrangement method and system, and relates to the technical field of tunnel engineering and shield tunneling machines. The method comprises the steps that the total flow of nozzles and the number of the nozzles are determined, and the sediment critical starting flow speed is calculated; obtaining a flow velocity-target distance formula according to a water jet theoretical formula, boundary value conditions and a momentum flux conservation theorem; according to the total flow of the nozzles, the number of the nozzles, the sediment critical starting flow speed and the flow speed-target distance formula, the nozzle arrangement target distance is obtained; and arranging the nozzles according to the nozzle arrangement target distance. According to the method, the arrangement target distance of the nozzles of the slurry shield cutter head is integrally and effectively designed in combination with the water jet theory and the sediment starting mechanism.

Description

Technical Field

[0001] The present application relates to the technical fields of tunnel engineering and shield machines, and in particular to a method and system for arranging cutterhead nozzles of a slurry shield. Background Art

[0002] With the continued development of urban underground space and the rapid advancement of cross-river and cross-sea tunnel projects, large-diameter slurry shield machines have become the core equipment for tunnel construction due to their excellent stability and efficiency in high water pressure and complex geological environments. As a key component of the slurry shield, one of the main functions of the cutterhead nozzle is to increase the flow characteristics of the flow field near the cutterhead excavation face through high-pressure mud injection, thereby smoothly removing mud particles. However, as the diameter of the tunnel increases (usually ≥10m), the construction difficulty increases significantly, so higher requirements are put forward in the design, selection and layout of the cutterhead nozzle.

[0003] Currently, the selection and placement of nozzles for large-diameter shield cutterheads mostly rely on empirical placement or numerical simulation of specific cutterheads to analyze the flow field characteristics of the cutterhead under different nozzle placement patterns and select the optimal one. These methods are highly subjective, incomplete, and have low design efficiency. Therefore, it is necessary to propose an optimized selection method to achieve a holistic and effective design of nozzles for large-diameter slurry shield cutterheads. Summary of the Invention

[0004] The purpose of this application is to provide a method and system for arranging the nozzles of the slurry shield cutter head, which can combine the water jet theory and the sediment starting mechanism to carry out an overall and effective design of the arrangement target distance of the slurry shield cutter head nozzles.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a method for arranging nozzles of a slurry shield cutter head, comprising:

[0007] Determine the total nozzle flow rate and the number of nozzles, and calculate the critical starting velocity of sediment;

[0008] According to the theoretical formula of water jet, boundary conditions and the conservation theorem of momentum flux, the flow velocity-target distance formula is obtained;

[0009] Obtaining the nozzle arrangement target distance according to the total nozzle flow, the number of nozzles, the critical starting flow velocity of sediment, and the flow velocity-target distance formula;

[0010] The nozzles are arranged according to the nozzle arrangement target distance.

[0011] Optionally, the slurry shield cutterhead nozzle arrangement method further includes:

[0012] Perform fluid simulation on different types of nozzles and determine the nozzle model based on the simulation results.

[0013] Optionally, the simulation results include the axial velocity, cross-sectional average velocity and diffusion angle of each type of nozzle in the flow field.

[0014] Optionally, the calculation formula for the critical starting velocity of sediment is as follows:

[0015]

[0016] Among them, ν cr is the critical starting velocity of sediment, K s is the influence coefficient of sediment content, s is the sediment content, ρ s is the density of sediment particles, γ s is the bulk density of sediment particles, γ is the bulk density of water flow, γ′ is the dry bulk density of sediment, and γ c is the stable dry density of sediment, V is the viscosity coefficient of water flow, g is the acceleration of gravity, h0 is the reference water depth corresponding to atmospheric pressure, h is the water depth, δ is the film water thickness, and D is the sediment particle size.

[0017] Optionally, the water jet theoretical formula includes a jet diffusion radius formula, a dynamic pressure calculation formula, an axial dynamic pressure distribution formula on any cross section, and a nozzle outlet flow rate formula.

[0018] Optionally, the flow velocity-target distance formula is as follows:

[0019]

[0020] Among them, v r' is the flow velocity at the target point, q is the flow rate of a single nozzle, π is pi, R0 is the radius of the nozzle outlet, r' is the straight-line distance between the jet outlet and the target point, and θ is the angle between the direction from the nozzle outlet to the target point and the nozzle axis direction.

[0021] Optionally, the nozzle arrangement target distance is obtained according to the total nozzle flow, the number of nozzles, the critical starting flow velocity of sediment, and the flow velocity-target distance formula, specifically including:

[0022] According to the total flow rate of the nozzle, the number of the nozzles and the critical starting velocity of sediment, based on the velocity-target distance formula, the maximum scour width and the maximum axial distance are obtained;

[0023] The nozzle arrangement target distance is obtained according to the maximum flushing width and the maximum axial distance.

[0024] Optionally, according to the total flow rate of the nozzle, the number of nozzles and the critical starting velocity of sediment, based on the velocity-target distance formula, the maximum scour width and the maximum axial distance are obtained, specifically including:

[0025] According to the number of nozzles and the total flow rate of the nozzles, a single nozzle flow rate and a nozzle outlet radius are obtained;

[0026] According to the single nozzle flow rate, the nozzle outlet radius and the critical starting flow velocity of sediment, based on the flow velocity-target distance formula, the maximum axial distance and the width-axial distance formula shown below are obtained:

[0027]

[0028] Wherein, x is the axial distance, b is the flushing width, q is the flow rate of the single nozzle, π is the pi, R0 is the nozzle outlet radius, v cr is the critical starting velocity of sediment;

[0029] The maximum scour width is obtained according to the width-axial distance formula.

[0030] Optionally, the nozzle arrangement target distance includes a center nozzle target distance and a panel nozzle target distance;

[0031] According to the maximum scouring width and the maximum axial distance, the nozzle arrangement target distance is obtained, which specifically includes:

[0032] Calculating the optimal axial distance corresponding to the maximum scour width;

[0033] According to the optimal axial distance, the center nozzle target distance is obtained;

[0034] The panel nozzle target distance is obtained according to the optimal axial distance and the maximum axial distance.

[0035] In a second aspect, the present application provides a slurry shield cutterhead nozzle arrangement system, comprising:

[0036] Data preparation module, used to determine the total nozzle flow rate and the number of nozzles, and calculate the critical starting velocity of sediment;

[0037] Formula building module, used to obtain the flow velocity-target distance formula based on the water jet theory formula, boundary conditions and momentum flux conservation theorem;

[0038] a target distance calculation module, configured to obtain the target distance for nozzle arrangement according to the total flow rate of the nozzle, the number of nozzles, the critical starting velocity of sediment, and the velocity-target distance formula;

[0039] The nozzle arrangement module is used to arrange the nozzles according to the nozzle arrangement target distance.

[0040] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0041] The present application provides a method and system for arranging nozzles of a slurry shield cutter head. Based on the theory of submerged water jet and the mechanism of sediment initiation, a flow velocity-target distance formula is established, which provides a theoretical basis for determining the target distance of nozzle arrangement and can carry out an overall and effective design of the target distance of the slurry shield cutter head nozzle arrangement. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 This is an application environment diagram of a slurry shield cutterhead nozzle arrangement method in one embodiment of the present application;

[0044] Figure 2 A schematic flow chart of a method for arranging cutterhead nozzles for a slurry shield provided in one embodiment of the present application;

[0045] Figure 3 A schematic diagram of the overall framework of a method for arranging cutterhead nozzles of a slurry shield provided in one embodiment of the present application;

[0046] Figure 4 A schematic diagram of the water jet structure of a high-pressure water jet nozzle provided in one embodiment of the present application;

[0047] Figure 5 A schematic diagram showing the relationship between the jet scouring width and the axial distance provided in one embodiment of the present application;

[0048] Figure 6 A schematic diagram of a simulation model provided in one embodiment of the present application;

[0049] Figure 7 A schematic diagram of the effect of local mesh encryption before division provided in one embodiment of the present application;

[0050] Figure 8 A schematic diagram of the effect of local mesh encryption provided in one embodiment of the present application;

[0051] Figure 9 A schematic diagram of axial velocity after simulation provided by an embodiment of the present application;

[0052] Figure 10A schematic diagram of the functional modules of a slurry shield cutterhead nozzle arrangement system provided in one embodiment of the present application;

[0053] Figure 11 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0055] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0056] The slurry shield cutter head nozzle arrangement method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set up separately, integrated on the server 104, or placed on the cloud or other servers. The terminal 102 can send the calculation results of the total nozzle flow, the number of nozzles and the critical starting flow velocity of sediment to the server 104. After receiving the relevant data, the server 104 obtains the flow velocity-target distance formula based on the water jet theory formula, boundary conditions and momentum flux conservation theorem, and obtains the nozzle arrangement target distance based on the total nozzle flow, the number of nozzles, the critical starting flow velocity of sediment and the flow velocity-target distance formula. The server 104 can feedback the obtained nozzle arrangement target distance to the terminal 102. In addition, in some embodiments, the slurry shield cutterhead nozzle arrangement method can also be implemented independently by the server 104 or the terminal 102. For example, the terminal 102 can directly calculate the nozzle arrangement target distance based on the calculation results of the total nozzle flow, the number of nozzles and the critical starting flow velocity of sediment, or the server 104 can obtain the calculation results of the total nozzle flow, the number of nozzles and the critical starting flow velocity of sediment from the data storage system and calculate the nozzle arrangement target distance.

[0057] Terminal 102 may include, but is not limited to, various desktop computers, laptops, smartphones, tablet computers, IoT devices, and portable wearable devices. IoT devices may include smart speakers, smart TVs, smart air conditioners, and smart car devices. Portable wearable devices may include smart watches, smart bracelets, and head-mounted devices. Server 104 may be implemented as a standalone server or a server cluster consisting of multiple servers, or may be a cloud server.

[0058] In an exemplary embodiment, Figure 2 As shown, a method for arranging nozzles of a slurry shield cutter head is provided. The method is executed by a computer device, specifically a computer device such as a terminal or a server, and can also be executed by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 1 The server 104 in the example is used as an example to illustrate the process, including the following steps 201 to 204.

[0059] Step 201: determine the total flow rate of the nozzle and the number of nozzles, and calculate the critical starting flow velocity of sediment.

[0060] Step 202: Obtain a flow velocity-target distance formula based on the water jet theory formula, boundary conditions, and the momentum flux conservation theorem.

[0061] Step 203 : Obtain the target distance for nozzle arrangement according to the total nozzle flow rate, the number of nozzles, the critical starting velocity of sediment, and the velocity-target distance formula.

[0062] Step 204 : Arrange the nozzles according to the nozzle arrangement target distance.

[0063] In an exemplary embodiment, Figure 3 As shown, this application establishes a velocity-target distance formula based on water jet theory combined with empirical formulas to effectively describe submerged water jets. Furthermore, to measure the flow field's disturbance capacity, the sediment starting velocity formula is introduced into the velocity-target distance formula, taking into account the sand content and mud cake particle size determined by engineering geological characteristics, thereby dividing the effective scouring area. Furthermore, the nozzle layout target distance is determined based on the calculated maximum scouring width and maximum axial distance, thus completing the cutterhead nozzle layout optimization process.

[0064] In one exemplary embodiment, the critical sediment initiation velocity is calculated using a formula for calculating sediment initiation velocity. This formula not only accounts for coarse and fine sand but also reflects the impact of sediment content on sediment initiation, making it more suitable for the complex geology of large-diameter slurry engineering projects. Because the critical sediment initiation velocity in the original formula is the average velocity perpendicular to the water flow, it is necessary to further determine the critical sediment initiation velocity actually acting on the sediment particles. The final formula is as follows:

[0065]

[0066] Among them, ν cr is the critical starting velocity of sediment, K s is the influence coefficient of sediment content, s is the sediment content, ρ s is the density of sediment particles, γ s is the bulk density of sediment particles, γ is the bulk density of water flow, γ′ is the dry bulk density of sediment, and γ c is the stable dry density of sediment, V is the viscosity coefficient of water flow, g is the acceleration of gravity, h0 is the reference water depth corresponding to atmospheric pressure, h is the water depth, δ is the film water thickness, and D is the sediment particle size.

[0067] In this embodiment, The value is 0.85, h0 is 10, and referring to the results of the cross quartz wire test, δ is 0.213×10 -6 .

[0068] In an exemplary embodiment, the flow rate-target distance formula is as follows:

[0069]

[0070] Among them, v r' is the flow velocity at the target point, q is the flow rate of a single nozzle, π is pi, R0 is the radius of the nozzle outlet, r' is the straight-line distance between the jet outlet and the target point, and θ is the angle between the direction from the nozzle outlet to the target point and the nozzle axis direction.

[0071] The water jet structure after the cleaning medium is ejected from the high-pressure water jet nozzle is as follows Figure 4 The submerged water jet is mainly divided into two sections, namely: the initial section 301 and the basic section 302. The outlet of the nozzle 303 is the jet core area 304, and the submerged water jet includes an inner boundary 305 and an outer boundary 306.

[0072] In the initial section 301 of the water jet, just after leaving the nozzle 303, the water jet has a high velocity and concentrated energy. However, this section is relatively short, which significantly affects the cleaning effect and therefore cannot be used as the primary operating section. However, the dynamic pressure in this section is relatively high, so it is generally used for high-pressure water jet cutting or rock breaking operations. In the basic section 302 of the water jet, the dynamic pressure is relatively stable, maintaining a continuous jet state, and this is also the main area of ​​action.

[0073] The outer boundary 306 of the submerged water jet is a straight line and the diffusion angle is approximately 28°. The jet diffusion radius can be expressed as

[0074] R=x×tanθ≈0.25x.

[0075] Where R is the jet diffusion radius, x is the axial distance, tan is the tangent function, and θ is the angle between the direction from the nozzle outlet to the target point and the nozzle axis direction, θ≤14°.

[0076] From fluid mechanics, we know that the stagnation pressure (dynamic pressure) of a water jet is:

[0077]

[0078] Where p is the dynamic pressure, ρ is the fluid density, and ν is the flow field velocity.

[0079] Based on the experimental curve of the axial dynamic pressure distribution of the jet, the axial dynamic pressure distribution on any cross section within the jet initial section 301 and basic section 302 is determined by the following empirical formula:

[0080]

[0081] Among them, p x is the dynamic pressure at any point on the jet cross section, p m is the dynamic pressure on the axis of the jet cross section, η is the dimensionless radial distance, r is the radial distance from the target to the jet axis, and R is the jet diffusion radius.

[0082] According to the law of conservation of momentum flux and using the boundary conditions of the initial segment 301 and the basic segment 302 , the variation law of the axial dynamic pressure with the target distance is obtained, and the length of the initial segment 301 can be further calculated.

[0083] As mentioned above, the dynamic pressure on the jet axis remains constant within the basic section 302. After passing the basic section 302, the axial dynamic pressure tends to decrease as the axial distance increases. In this embodiment, the following five assumptions are first proposed:

[0084] (1) There is no air-water mixing caused by the entrainment of the water jet. (2) The static pressure at the jet boundary is atmospheric pressure. (3) The jet at the nozzle outlet is a uniform flow. (4) There are no external forces affecting the jet. (5) There is no energy loss between the jet and the outside world.

[0085] According to the law of conservation of momentum flux, the initial momentum flux of the water jet at the outlet section is equal to the momentum flux on any section within the main section of the jet, that is:

[0086]

[0087] Among them, J0 is the initial momentum flux of the water jet at the outlet section, J X is the momentum flux on any cross section in the main section of the jet, π is the pi, R0 is the nozzle outlet radius, ρ is the fluid density, ν0 is the nozzle outlet velocity, R is the jet diffusion radius, ν x is the flow velocity at a certain point on the axis, and r is the radial distance from the target point to the jet axis.

[0088] Depend on So, dr=Rdη, substituting into the above formula we can get:

[0089]

[0090] Among them, ν m is the flow velocity when the jet just enters the initial section.

[0091] Further, R≈0.25x, Substituting into the above formula, we can get:

[0092]

[0093] Using the boundary conditions of the initial segment 301 to transition to the basic segment 302, We can get:

[0094]

[0095] Among them, x p is the length of the basic section of jet constant velocity.

[0096] Considering the dynamic similarity condition, the variation law of axial dynamic pressure with target distance can be obtained:

[0097]

[0098] From this we can get,

[0099]

[0100] The nozzle outlet flow rate can be calculated based on the single nozzle flow rate:

[0101]

[0102] Where q is the flow rate of a single nozzle.

[0103] Combining the above formulas:

[0104]

[0105] The velocity-target distance formula at any point in the jet flow field can be obtained:

[0106]

[0107] Furthermore, on the axis, that is, when θ = 0°, the relationship between the flow field velocity and the axial distance is as follows:

[0108]

[0109] In an exemplary embodiment, the above step 203 may be replaced by the following steps 2031 and 2032:

[0110] Step 2031 : According to the total nozzle flow, the number of nozzles, and the critical starting velocity of sediment, the maximum scouring width and the maximum axial distance are obtained based on the velocity-target distance formula.

[0111] Step 2032: Obtain the nozzle arrangement target distance according to the maximum scouring width and the maximum axial distance.

[0112] In an exemplary embodiment, the above step 2031 may be replaced by the following steps 301 to 303:

[0113] Step 301: Obtain the flow rate of a single nozzle and the nozzle outlet radius according to the number of nozzles and the total flow rate of the nozzles.

[0114] Step 302: Based on the flow rate of a single nozzle, the nozzle outlet radius, and the critical starting velocity of sediment, the maximum axial distance is obtained based on the flow rate-target distance formula, as well as the width-axial distance formula shown below:

[0115]

[0116] Where x is the axial distance, b is the scouring width, q is the flow rate of a single nozzle, π is the circumference, R0 is the nozzle outlet radius, v cr is the critical starting velocity of sediment.

[0117] Step 303: Obtain the maximum scour width according to the width-axial distance formula.

[0118] In an exemplary embodiment, the nozzle arrangement target distance includes the center nozzle target distance and the panel nozzle target distance. The above step 2032 can be replaced by the following steps 401-403:

[0119] Step 401: Calculate the optimal axial distance corresponding to the maximum scour width.

[0120] Step 402: Obtain the center nozzle target distance based on the optimal axial distance.

[0121] Step 403: Obtain the panel nozzle target distance according to the optimal axial distance and the maximum axial distance.

[0122] In an exemplary embodiment, the calculation formula for a single nozzle flow rate is as follows:

[0123]

[0124] Where q is the flow rate of a single nozzle, Q is the total flow rate of the nozzle, and N is the number of nozzles.

[0125] The calculation formula for the nozzle outlet diameter is as follows:

[0126]

[0127] Where D0 is the nozzle outlet diameter, q is the flow rate of a single nozzle, C d is the nozzle flow coefficient, p b is the rated pressure of the pump.

[0128] Taking a large-diameter mud-water project as an example, according to the engineering geological characteristics, the critical starting velocity of sediment v is calculated. cr Assume that the total nozzle flow rate Q is 1000m 3 / h, the number of nozzles N is 6. According to the above formula, the flow rate q of a single nozzle is 0.0463m 3 / s, the nozzle outlet radius R0 is 30mm. The single nozzle flow rate q, nozzle outlet radius R0 and sediment critical starting velocity ν cr , substituting into the velocity-target distance formula, we can get

[0129]

[0130] Among them, r' N＝6 is the straight-line distance between the jet outlet and the target point when the number of nozzles is 6.

[0131] Substituting θ=0 into the above formula, we obtain that the maximum axial distance of the effective jet area is 3.893m.

[0132] Will Substituting into the above formula, we can get:

[0133] b e =3.893tanθ-62.287×tan 2.5 θ+249.147×tan 4 θ.

[0134] Among them, b e is the scouring width when the number of nozzles is 6.

[0135] Will Substituting the above formula, we can get the width-axial distance formula when the number of nozzles is 6 as shown below:

[0136]

[0137] Where x is the axial distance.

[0138] According to the above formula, we can get Figure 5 The curve shown in the figure can be solved to obtain that when the axial distance x=2.19m, the scouring width of the jet is the largest, and the maximum scouring width is 0.434m.

[0139] The center nozzle is mainly used to flush the center cutter of the cutterhead. Since the opening in the center of the cutterhead is small and sediment is easily accumulated, this type of nozzle needs to have a larger flushing coverage width on the center cutter surface.

[0140] The panel nozzle is responsible for disturbing the flow field in the cutter disc panel area. This area is the main action area of ​​tool cutting. There are many slag particles and the area is large. Therefore, the panel flushing nozzle needs to have a larger effective flushing range.

[0141] Based on the above functional requirements, the nozzle arrangement target distance is obtained according to the maximum scouring width and the maximum axial distance.

[0142] like Figure 5 As shown in the figure, the effective scouring width of the jet increases first and then decreases with the increase of axial distance, indicating that the jet has an optimal scouring width within a certain distance range. In this embodiment, the maximum scouring width of the jet is 0.434m, corresponding to an axial distance of 2.19m. As the axial distance continues to increase, the scouring width gradually decreases and decays to zero at an axial distance of 3.893m, i.e., the maximum axial distance. This can be considered the maximum effective scouring distance of the jet. Beyond this distance, the flow field velocity will be less than the critical starting effective velocity of the sediment particles, and the flow field will no longer have the ability to scour.

[0143] Therefore, based on the calculation results of the maximum scouring width and the maximum axial distance, as well as the functional characteristics of the nozzles in different areas, the center nozzle target distance is obtained according to the optimal axial distance, that is, the center nozzle target distance is set at about 2.19m from the center tool, that is, the layout radius is 2.19m, to achieve the maximum scouring width. Based on the optimal axial distance and the maximum axial distance, the panel nozzle target distance is obtained. Since the spray direction of the panel nozzle is also toward the center of the cutter disc, there is a direction overlap with the center nozzle. In order to avoid interference between the jet areas of the nozzles and cause energy loss, the layout position of the panel nozzle should be greater than 3.893m away from the center nozzle in the same direction, that is, beyond the maximum axial distance, so as to ensure that the panel scouring nozzle has the largest effective scouring range.

[0144] In an exemplary embodiment, Figure 3 As shown, the slurry shield cutterhead nozzle arrangement method also includes fluid simulation of different nozzle types and determining the nozzle model based on the simulation results. This embodiment uses numerical simulations in ANSYS Fluent based on the four most commonly used continuous straight flow nozzles in engineering practice: straight nozzles, tapered straight nozzles, inner arc nozzles, and outer arc nozzles. The nozzle structure is selected based on three aspects: axial velocity, cross-sectional average velocity, and diffusion angle of the flow field. The results of the theoretical model can be cross-validated with the nozzle simulation results to verify their effectiveness.

[0145] Based on actual engineering design requirements, the main structural parameters of the nozzle, such as the nozzle inlet diameter, outlet diameter, and contraction section length, were first determined. Then, three-dimensional models of four nozzles were created and locally refined mesh simulations were performed in ANSYS Fluent to analyze the axial velocity, cross-sectional average velocity, and diffusion angle of each nozzle type in the flow field. Taking the tapered straight nozzle as an example, the specific simulation steps are as follows:

[0146] 1. Ensure that the inlet and outlet diameters and the length of the contraction section are consistent. Build a three-dimensional model of the nozzle and the corresponding flow field model in ANSYS Design Modeler. The established simulation model is as follows: Figure 6 shown.

[0147] 2. Considering the computational efficiency, we adopt local meshing to mesh the fluid domain inside the nozzle and near the nozzle outlet. We adopt the geometric size adjustment method, define the type as the influence range, define the center of the sphere as the center coordinate of the nozzle outlet, and appropriately enlarge or reduce the grid unit size according to the size of the nozzle structure parameters. The effects before and after local meshing are as follows: Figure 7 and Figure 8 shown.

[0148] 3. In the parameter setting stage, the solver selects the pressure base and performs a steady-state solution. The VOF multiphase flow coupling model is used to define the fluid materials as air and the nozzle slurry parameters, and the air and slurry are assigned separately in the VOF phase setting. The standard k-ε model is used. This model has high computational efficiency and is suitable for complex flow problems in engineering. It has strong robustness, good convergence, and relatively low dependence on initial conditions and mesh quality. The default parameters are highly universal and can be applied to most jet scenarios without frequent adjustments. Set the boundary conditions. For the inlet, you can choose the definition type as a mass flow inlet or a velocity inlet, and define the volume fraction of the slurry phase. In the outlet boundary conditions, set the backflow volume fraction to 0 to ensure that the water jet does not flow back into the flow field. Further unit marking is performed to create a domain that can contain the set nozzle and flow field model. In the initialization definition, the corresponding parameters of the inlet are initialized, and further local initialization is performed on the entire domain. The mud volume fraction is set to 1 to ensure that the flow field is full of mud, thereby simulating the flow field of the cutterhead nozzle under the submerged jet.

[0149] The axial velocity cloud obtained by simulation is as follows: Figure 9 The above simulation operations are performed on different types of nozzles respectively, and the nozzle type is selected by comparing the axial velocity, cross-sectional average velocity and diffusion angle of each type of nozzle in the flow field.

[0150] Based on the same inventive concept, embodiments of the present application also provide a slurry shield cutterhead nozzle arrangement system for implementing the aforementioned slurry shield cutterhead nozzle arrangement method. The solution provided by this system is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more embodiments of the slurry shield cutterhead nozzle arrangement system provided below can be found in the limitations of the slurry shield cutterhead nozzle arrangement method described above and will not be repeated here.

[0151] In an exemplary embodiment, Figure 10 As shown, a slurry shield cutterhead nozzle arrangement system is provided, comprising:

[0152] The data preparation module 1001 is used to determine the total flow rate and the number of nozzles, and calculate the critical starting velocity of sediment.

[0153] The formula building module 1002 is used to obtain the flow velocity-target distance formula based on the water jet empirical formula, boundary conditions and momentum flux conservation theorem.

[0154] The target distance calculation module 1003 is used to obtain the nozzle arrangement target distance based on the total nozzle flow, the number of nozzles, the critical starting flow velocity of sediment and the flow velocity-target distance formula.

[0155] The nozzle arrangement module 1004 is used to arrange the nozzles according to the nozzle arrangement target distance.

[0156] The beneficial effects of this application are as follows:

[0157] This application can significantly improve the perturbation capacity of the slurry shield cutterhead nozzle on the flow field, improve the excavation efficiency of the large-diameter slurry shield cutterhead, and the optimized nozzle layout can enhance the flushing effect of the water jet, effectively reduce sediment accumulation, and reduce construction delays caused by poor slag discharge, thereby improving the overall excavation efficiency. This application combines numerical simulation with theoretical derivation, and mutually verifies that the traditional empirical layout method is mostly transformed into a quantitative optimization based on theoretical derivation and numerical simulation, ensuring that the design results are more in line with actual working conditions and have high reliability and universality. On the other hand, this application is suitable for the construction needs of large-diameter shield machines under high water pressure and complex formation conditions, providing a scientific and systematic design optimization solution for similar complex projects, and has good promotion and application value.

[0158] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 11As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O) and a communication interface. The processor, memory and input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store the calculation results of the total nozzle flow, the number of nozzles and the critical starting flow rate of sediment. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for arranging the nozzles of the slurry shield cutter head is implemented.

[0159] Those skilled in the art will understand that Figure 11 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0160] In an exemplary embodiment, a computer device is further provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0161] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0162] In an exemplary embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0163] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0164] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0165] The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may include, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic units, data processing logic units based on quantum computing, and the like.

[0166] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0167] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for arranging nozzles of a slurry shield cutter head, characterized in that: The slurry shield cutterhead nozzle arrangement method includes: Determine the total nozzle flow rate and the number of nozzles, and calculate the critical starting velocity of sediment; According to the theoretical formula of water jet, boundary conditions and the conservation theorem of momentum flux, the flow velocity-target distance formula is obtained; Obtaining the nozzle arrangement target distance according to the total nozzle flow, the number of nozzles, the critical starting flow velocity of sediment, and the flow velocity-target distance formula; The nozzles are arranged according to the nozzle arrangement target distance.

2. The method for arranging cutterhead nozzles of a slurry shield according to claim 1, characterized in that: The slurry shield cutterhead nozzle arrangement method further includes: Perform fluid simulation on different types of nozzles and determine the nozzle model based on the simulation results.

3. The method for arranging cutterhead nozzles of a slurry shield according to claim 2, characterized in that: The simulation results include the axial velocity, cross-sectional average velocity and diffusion angle of each type of nozzle in the flow field.

4. The method for arranging cutterhead nozzles of a slurry shield according to claim 1, characterized in that: The calculation formula of the critical starting velocity of sediment is as follows: Among them, ν cr is the critical starting velocity of sediment, K s is the influence coefficient of sediment content, s is the sediment content, ρ s is the density of sediment particles, γ s is the bulk density of sediment particles, γ is the bulk density of water flow, γ′ is the dry bulk density of sediment, and γ c is the stable dry density of sediment, V is the viscosity coefficient of water flow, g is the acceleration of gravity, h0 is the reference water depth corresponding to atmospheric pressure, h is the water depth, δ is the film water thickness, and D is the sediment particle size.

5. The method for arranging cutterhead nozzles of a slurry shield according to claim 1, characterized in that: The water jet theoretical formula includes a jet diffusion radius formula, a dynamic pressure calculation formula, an axial dynamic pressure distribution formula on any cross section, and a nozzle outlet flow rate formula.

6. The method for arranging cutterhead nozzles of a slurry shield according to claim 1, characterized in that: The flow rate-target distance formula is as follows: Among them, v r' is the flow velocity at the target point, q is the flow rate of a single nozzle, π is pi, R0 is the radius of the nozzle outlet, r' is the straight-line distance between the jet outlet and the target point, and θ is the angle between the direction from the nozzle outlet to the target point and the nozzle axis direction.

7. The method for arranging cutterhead nozzles of a slurry shield according to claim 1, characterized in that: The nozzle arrangement target distance is obtained according to the total nozzle flow, the number of nozzles, the critical starting flow velocity of sediment, and the flow velocity-target distance formula, specifically including: According to the total flow rate of the nozzle, the number of the nozzles and the critical starting velocity of sediment, based on the velocity-target distance formula, the maximum scour width and the maximum axial distance are obtained; The nozzle arrangement target distance is obtained according to the maximum flushing width and the maximum axial distance.

8. The method for arranging cutterhead nozzles of a slurry shield according to claim 7, characterized in that: According to the total flow rate of the nozzle, the number of nozzles, and the critical starting velocity of sediment, based on the velocity-target distance formula, the maximum scour width and the maximum axial distance are obtained, specifically including: According to the number of nozzles and the total flow rate of the nozzles, a single nozzle flow rate and a nozzle outlet radius are obtained; According to the single nozzle flow rate, the nozzle outlet radius and the critical starting flow velocity of sediment, based on the flow velocity-target distance formula, the maximum axial distance and the width-axial distance formula shown below are obtained: Wherein, x is the axial distance, b is the flushing width, q is the flow rate of the single nozzle, π is the pi, R0 is the nozzle outlet radius, v cr is the critical starting velocity of sediment; The maximum scour width is obtained according to the width-axial distance formula.

9. The method for arranging cutterhead nozzles of a slurry shield according to claim 7, characterized in that: The nozzle arrangement target distance includes the center nozzle target distance and the panel nozzle target distance; According to the maximum scouring width and the maximum axial distance, the nozzle arrangement target distance is obtained, which specifically includes: Calculating the optimal axial distance corresponding to the maximum scour width; According to the optimal axial distance, the center nozzle target distance is obtained; The panel nozzle target distance is obtained according to the optimal axial distance and the maximum axial distance.

10. A slurry shield cutterhead nozzle arrangement system, characterized in that: The slurry shield cutterhead nozzle arrangement system includes: Data preparation module, used to determine the total nozzle flow rate and the number of nozzles, and calculate the critical starting velocity of sediment; Formula building module, used to obtain the flow velocity-target distance formula based on the water jet theory formula, boundary conditions and momentum flux conservation theorem; a target distance calculation module, configured to obtain the target distance for nozzle arrangement according to the total flow rate of the nozzle, the number of nozzles, the critical starting velocity of sediment, and the velocity-target distance formula; The nozzle arrangement module is used to arrange the nozzles according to the nozzle arrangement target distance.

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