Optimization method for reducing internal pipeline pressure loss and overall light weight of hydraulic valve block based on additive manufacturing

Abstract

The invention discloses an optimization method for reducing internal pipeline pressure loss of a hydraulic valve block and integrally lightening based on additive manufacturing, which comprises the following steps of: extracting internal pipeline models of the hydraulic valve block according to the hydraulic valve block needing to be optimized, grouping the internal pipeline models, analyzing pressure loss reasons, and performing preliminary optimization based on the characteristics of the additive manufacturing; and carrying out topological optimization design on the preliminarily optimized pipeline, re-establishing an internal pipeline model of the hydraulic valve block, carrying out lightweight design on the basis, and carrying out 3D printing on the model for verification. The energy utilization rate of the hydraulic system is increased, and the reliability and the working efficiency of the hydraulic system are improved; the hydraulic valve block which is compact in structure, light in weight and convenient to transport and carry can be optimized according to different requirements, a complex hydraulic valve block can be customized, and the manufacturing period is greatly shortened; and raw materials are saved, the energy consumption is reduced, remarkable economic benefits are brought to enterprises, and great significance is achieved for building a resource-saving society.

Description

Technical Field

[0001] The present invention relates to the fields of additive manufacturing and hydraulics, and in particular to an optimization method for reducing pressure loss in pipelines inside a hydraulic valve block and achieving overall lightweighting based on additive manufacturing. Background Art

[0002] Hydraulic systems are widely used in many key fields such as aerospace, automobile manufacturing, and shipbuilding. The hydraulic integrated valve block, as the core component of the integrated hydraulic system, is a porous channel body carefully designed according to the system requirements. The hydraulic integrated valve block, as the core component of the integrated hydraulic system, is a porous channel body carefully designed according to the system requirements. In the manufacturing process of the hydraulic integrated valve block, the processing of the internal channels has always been a technical difficulty. Traditional subtractive processing methods such as drilling, expanding, reaming, and tapping often form complex orthogonal, non-orthogonal right-angle turning channels and process hole cavities inside the valve block, which not only increases the complexity of the flow field structure, but also leads to serious local pressure loss. For example, under specific working conditions (the hydraulic oil density is 900kg / m 3 , dynamic viscosity coefficient is 0.0405Pa·s, inlet velocity is 8.5m / s, outlet pressure is 10MPa), and the hydraulic oil loses about 0.1MPa of energy when passing through each right-angle turn. In addition, when processing hydraulic integrated valve blocks using traditional subtractive manufacturing methods, some internal channels cannot be directly processed, and the internal channels must be connected through process holes. However, during use, the sealing of process holes often becomes a problem. Once the sealing is not strict, it will cause hydraulic oil leakage, which not only pollutes the environment, but also seriously affects the reliability and work efficiency of the hydraulic system. Therefore, studying how to reduce the pressure loss in the internal channels of the valve block and the overall lightweighting is of great significance to improving the energy utilization of the hydraulic system. Summary of the Invention

[0003] Purpose of the invention: The purpose of the present invention is to provide an optimization method based on additive manufacturing to reduce the pressure loss of the internal pipeline of the hydraulic valve block and the overall lightweight.

[0004] Technical solution: The method of the present invention comprises the following steps:

[0005] Step 1: According to the hydraulic valve block to be optimized, extract the internal pipeline model of the hydraulic valve block and group it, and use FLUENT to analyze the internal pipeline liquid flow pressure loss;

[0006] Step 2: Analyze the cause of pressure loss and perform preliminary optimization based on the characteristics of additive manufacturing. Then use FLUENT simulation to verify whether the optimization meets the optimization requirements.

[0007] Step 3: Based on the optimization results of step 2 and the characteristics of additive manufacturing, perform topology optimization design on the initially optimized pipeline, and use FLUENT simulation to verify whether the topology optimization design meets the optimization requirements;

[0008] Step 4: Re-establish the internal pipeline model of the hydraulic valve block based on the optimization results of step 3, and perform lightweight design on this basis;

[0009] Step 5: Based on the internal pipeline model and lightweight design of the hydraulic valve block re-established in step 4, the model is 3D printed to verify the feasibility of the optimization method based on additive manufacturing to reduce the pressure loss of the internal pipeline of the hydraulic valve block and the overall lightweighting.

[0010] Furthermore, the preliminary optimization in step 2 includes optimizing according to whether to change the positions of the inlet and outlet and the flow channel shape of the internal pipeline.

[0011] Furthermore, the optimization according to whether to change the positions of the inlet and outlet includes: if the positions of the inlet and outlet are changed, the relative positions on the plane where the inlet and outlet are located are brought closer together without interfering with other groups of pipelines.

[0012] Furthermore, the optimization by changing the flow channel shape of the internal pipe includes:

[0013] If the flow channel shape of the internal pipeline is changed without interfering with other groups of pipelines, the center of the flow channel is located in the plane of the inlet and outlet, and the flow channel shape is set to be flat; if only the right-angle turns are changed, the linear impact on the pipe wall is reduced at the turns based on the reduction of turbulence.

[0014] Furthermore, the topology optimization design method in step 3 includes:

[0015] Turbulence is determined based on the Reynolds number, which is defined as the ratio of inertial force to viscous force:

[0016]

[0017] Where: ρ is the fluid density, u is the characteristic velocity, L is the characteristic length, μ is the dynamic viscosity,

[0018] v = μ / ρ represents kinematic viscosity;

[0019] The critical value for the flow state to change from laminar to turbulent is: laminar flow: Re<2300; transition flow: 2300<Re<4000; turbulent flow: Re>4000.

[0020] Furthermore, the lightweight design in step 4 includes:

[0021] Step 4.1: Based on the optimized pipeline path and boundary conditions, the algorithm generates the optimal material distribution, reducing weight by 30%-70%;

[0022] Step 4.2: Use microscale lattices instead of solid materials to achieve high specific stiffness and energy absorption;

[0023] Step 4.3: Mimic the lightweight properties of natural structures;

[0024] Step 4.4: Use materials with low density and good performance.

[0025] Furthermore, the algorithms adopted in step 4.1 include variable density method and level set method.

[0026] Furthermore, in the 3D printing process, step 5 needs to consider whether to add support, the method of adding support, and the method of efficiently removing support.

[0027] Furthermore, in step 5, the model is 3D printed to achieve self-support by modifying the caliber according to the printing process adopted when optimizing the pipeline model. The method of increasing the support includes adjusting the size and density of the support to the optimal value during the digital model processing before printing.

[0028] Furthermore, the efficient support removal method includes friction deposition, liquid immersion and vibration, which is selected according to process requirements.

[0029] Beneficial effects: Compared with the existing technology, the present invention has the following significant advantages: it can reduce the pressure loss of the internal pipeline of the optimized hydraulic valve block, improve the energy utilization rate of the hydraulic system, and increase the reliability and working efficiency of the hydraulic system; it can optimize the hydraulic valve block with compact structure, light weight, and easy transportation and handling according to different needs, and can customize complex hydraulic valve blocks. Compared with traditional machining methods, the manufacturing cycle is greatly shortened; it saves raw materials, reduces energy consumption, brings significant economic benefits to enterprises, and is of great significance to building a resource-saving society. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flow chart for constructing the present invention;

[0031] Figure 2 Optimize the special case structure diagram for the first set of pipelines;

[0032] Figure 3 Optimize the special case structure diagram for the second set of pipelines;

[0033] Figure 4 This is the optimized pipeline model diagram of a hydraulic valve block. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0035] like Figure 1 As shown, the optimization method for reducing pressure loss in the internal pipeline of a hydraulic valve block and reducing overall weight based on additive manufacturing according to the present invention comprises the following steps:

[0036] Step 1: Based on the hydraulic valve block to be optimized, extract the internal pipeline model of the hydraulic valve block and group it. Use FLUENT to analyze the internal pipeline liquid flow pressure loss for each group of internal pipeline models. Each group of internal pipeline models must complete steps 2 and 3 in sequence before continuing to the subsequent steps.

[0037] Step 2: Analyze the cause of pressure loss and perform preliminary optimization based on the characteristics of additive manufacturing. During the optimization process, consider whether the oil inlet and outlet ports can be changed, whether the diameter of the pipeline can be adjusted, and other issues. Specific analysis is required. In this example, the oil inlet and outlet ports and the diameter of the pipeline are not changed. Then use FLUENT simulation to verify whether the optimization meets the optimization requirements. During the optimization process, consider whether the oil inlet and outlet ports can be changed, whether the diameter of the pipeline can be adjusted, and other issues. Specific analysis is required. In this example, the oil inlet and outlet ports and the diameter of the pipeline are not changed.

[0038] Depending on whether the position of the inlet and outlet and the shape of the flow channel of the internal pipeline can be changed, if the position of the inlet and outlet can be changed, the relative positions can be as close as possible on the plane where the inlet and outlet are located without interfering with other groups of pipelines; if the shape of the flow channel of the internal pipeline can be changed, the center of the flow channel can be placed in the plane of the inlet and outlet as much as possible without interfering with other groups of pipelines, and the shape of the flow channel can be made as flat as possible; if only the right-angle turns are changed, then in order to reduce turbulence, the straight-line impact on the pipe wall will be reduced as much as possible at the turns.

[0039] Step 3: Based on the optimization results of step 2 and the characteristics of additive manufacturing, the topology optimization design of the initially optimized pipeline is carried out, and FLUENT simulation is used to verify whether the topology optimization design meets the optimization requirements. The optimization example is as follows: Figure 2 、 3 As shown in the figure, during the topology optimization process, because this method is oriented towards additive manufacturing, it is possible to consider which supports can be avoided during the printing process. During the optimization, the pipeline can be designed without support based on the algorithm. The main reference indicators of the algorithm are mass and pressure loss. The specific part of the pipeline that can be designed without support must be combined with actual requirements, printing methods and other specific factors.

[0040] Topology optimization design methods include:

[0041] Turbulence is determined based on the Reynolds number, which is defined as the ratio of inertial force to viscous force:

[0042]

[0043] Where: ρ is the fluid density, u is the characteristic velocity, L is the characteristic length, μ is the dynamic viscosity,

[0044] v = μ / ρ represents kinematic viscosity;

[0045] The critical value for the flow state to change from laminar to turbulent is: laminar flow: Re<2300; transition flow: 2300<Re<4000; turbulent flow: Re>4000.

[0046] Step 4: Re-establish the internal pipeline model of the hydraulic valve block based on the optimization results of step 3, such as Figure 4 As shown, lightweight design is carried out on this basis. There are many methods for lightweight design, such as hollowing out the interior of the model, changing the material of the hydraulic valve block, and selecting materials with better performance and lighter density. The specific design methods must be carried out without affecting the original purpose and without reducing the performance.

[0047] ① Based on the optimized pipeline path and boundary conditions, the optimal distribution of materials is generated through algorithms (variable density method, level set method), which can achieve a weight reduction of 30%-70%;

[0048] ② Use microscale lattices (such as TPMS and BCC) instead of solid materials to achieve high specific stiffness and energy absorption;

[0049] ③ Mimicking the lightweight properties of natural structures (such as bones and honeycombs), such as fractal structures and dendritic supports;

[0050] ④ Use materials with lower density and better performance.

[0051] Step 5: 3D print the model based on the internal pipeline model and lightweight design of the hydraulic valve block re-established in step 4 to verify the feasibility of the additive manufacturing-based optimization method for reducing the pressure loss in the internal pipeline of the hydraulic valve block and the overall lightweighting. Currently, there are many mature 3D printing forms, such as SLA, SLS, SLM and BJ. You can choose the appropriate printing process based on budget, materials, requirements, etc.

[0052] During the 3D printing process, it is necessary to consider whether support is needed, how to add support, and how to remove support efficiently. Whether support is needed can be determined by modifying the diameter to achieve self-support when optimizing the pipeline model according to the printing process used. How to add support can be determined by adding efficient support during the digital model processing before printing, and adjusting the size and density of the support to the optimal level to facilitate subsequent process processing. There are many efficient support removal methods, such as friction deposition, liquid immersion, vibration, etc., which can be selected according to process requirements.

Claims

1. An optimization method based on additive manufacturing to reduce pressure loss in the internal pipeline of a hydraulic valve block and reduce overall weight, characterized in that: The steps include: Step 1: According to the hydraulic valve block to be optimized, extract the internal pipeline model of the hydraulic valve block and group it, and use FLUENT to analyze the internal pipeline liquid flow pressure loss; Step 2: Analyze the cause of pressure loss and perform preliminary optimization based on the characteristics of additive manufacturing. Then use FLUENT simulation to verify whether the optimization meets the optimization requirements. Step 3: Based on the optimization results of step 2 and the characteristics of additive manufacturing, perform topology optimization design on the initially optimized pipeline, and use FLUENT simulation to verify whether the topology optimization design meets the optimization requirements; Step 4: Re-establish the internal pipeline model of the hydraulic valve block based on the optimization results of step 3, and perform lightweight design on this basis; Step 5: Based on the internal pipeline model and lightweight design of the hydraulic valve block re-established in step 4, the model is 3D printed to verify the feasibility of the optimization method based on additive manufacturing to reduce the pressure loss of the internal pipeline of the hydraulic valve block and the overall lightweighting.

2. The optimization method for reducing pressure loss in internal pipelines of a hydraulic valve block and achieving overall lightweighting based on additive manufacturing according to claim 1, characterized in that: The preliminary optimization in step 2 includes optimizing based on whether to change the positions of the inlet and outlet and the flow channel shape of the internal pipeline.

3. The optimization method for reducing pressure loss in internal pipelines of a hydraulic valve block and achieving overall lightweighting based on additive manufacturing according to claim 2, characterized in that: The optimization according to whether to change the positions of the inlet and outlet includes: if the positions of the inlet and outlet are changed, the relative positions of the inlet and outlet are brought closer on the plane where the inlet and outlet are located without interfering with other groups of pipelines.

4. The optimization method for reducing pressure loss in internal pipelines of a hydraulic valve block and achieving overall lightweighting based on additive manufacturing according to claim 2, characterized in that: The optimization by changing the flow channel shape of the internal pipeline includes: if the flow channel shape of the internal pipeline is changed, without interfering with other groups of pipelines, the center of the flow channel is located in the plane of the inlet and outlet, and the flow channel shape is set to be flat; if only the right-angle turns are changed, then according to the situation of reducing turbulence, the linear impact on the pipe wall at the turns is reduced.

5. The optimization method for reducing pressure loss in internal pipelines of a hydraulic valve block and achieving overall lightweighting based on additive manufacturing according to claim 1, characterized in that: The topology optimization design method in step 3 includes: Turbulence is determined based on the Reynolds number, which is defined as the ratio of inertial force to viscous force: Where: ρ is the fluid density, u is the characteristic velocity, L is the characteristic length, μ is the dynamic viscosity, v = μ / ρ represents kinematic viscosity; The critical value for the flow state to change from laminar to turbulent is: laminar flow: Re < 2300; transition flow: 2300 < Re < 4000; turbulent flow: Re > 4000.

6. The optimization method for reducing pressure loss in internal pipelines of a hydraulic valve block and achieving overall lightweighting based on additive manufacturing according to claim 1, characterized in that: The lightweight design in step 4 includes: Step 4.1: Based on the optimized pipeline path and boundary conditions, the algorithm generates the optimal material distribution, reducing weight by 30%-70%; Step 4.2: Use microscale lattices instead of solid materials to achieve high specific stiffness and energy absorption; Step 4.3: Mimic the lightweight properties of natural structures; Step 4.4: Use materials with low density and good performance.

7. The optimization method for reducing pressure loss in internal pipelines of a hydraulic valve block and achieving overall lightweighting based on additive manufacturing according to claim 6, characterized in that: The algorithms used in step 4.1 include variable density method and level set method.

8. The optimization method for reducing pressure loss in internal pipelines of a hydraulic valve block and achieving overall lightweighting based on additive manufacturing according to claim 1, characterized in that: In the 3D printing process, step 5 needs to consider whether to add support, the method of adding support, and the method of efficiently removing support.

9. The optimization method for reducing pressure loss in internal pipelines of a hydraulic valve block and achieving overall lightweighting based on additive manufacturing according to claim 8, characterized in that: In step 5, the model is 3D printed by modifying the caliber according to the printing process adopted when optimizing the pipeline model to achieve self-support. The method of increasing the support includes adjusting the size and density of the support to the optimal level during the digital model processing before printing.

10. The optimization method for reducing pressure loss in internal pipelines of a hydraulic valve block and achieving overall lightweighting based on additive manufacturing according to claim 8, characterized in that: The efficient support removal methods include friction deposition, liquid immersion, and vibration, which are selected according to process requirements.

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