A topology optimization design method for electric spindle cooling jacket

Abstract

The present invention relates to a topological optimization design method for a liquid cooling channel of an electric spindle cooling jacket, and the steps are as follows: Step 1, topological optimization design of a two-dimensional plane channel, taking into account the gravity of the cooling medium, controlling the volume fraction of the fluid channel, and obtaining the distribution form of the channel in the two-dimensional plane design domain based on the flow-heat coupling topological optimization design technology; Step 2, construction of a three-dimensional electric spindle cooling jacket, extracting the two-dimensional channel contour distribution curve, stretching modeling to obtain a plane liquid cooling plate, and then bending the liquid cooling plate 360° with the mid-plane as the reference plane to obtain a three-dimensional cylindrical electric spindle cooling jacket channel structure. The topological optimization design method proposed by the present invention, which takes into account the gravity of the cooling medium and controls the volume fraction of the liquid cooling channel, has excellent performance in the designed electric spindle cooling jacket, especially in terms of temperature uniformity, maximum temperature and pressure drop control, showing superior performance.

Description

Technical Field

[0001] The invention relates to an optimization design method for an electric spindle cooling jacket, in particular to a topology optimization design method for a liquid cooling channel of an electric spindle cooling jacket. Background Art

[0002] In the research field of high-end CNC machine tools, improving the machining accuracy of machine tools is a key research point and a technical difficulty. As the largest heat source of CNC machine tools, the thermal deformation of the electric spindle will directly affect the machining accuracy of the machine tools. Therefore, an efficient heat dissipation method for the electric spindle is of great significance to improving the machining accuracy of machine tools.

[0003] At present, for the design of heat dissipation flow channels of electric spindle cooling sleeves, the more common flow channel form is the spiral groove flow channel. Although this type of cooling sleeve flow channel has a simple structure and is easy to process, it consumes large power and its heat dissipation effect can no longer meet the needs of electric spindles with higher heat generation. Its uneven temperature distribution also causes certain difficulties in the thermal error compensation of the electric spindle. Summary of the invention

[0004] The present invention proposes a topological optimization design method for the liquid-cooling flow channel of an electric spindle cooling jacket. By performing flow-heat coupling topological optimization in a plane design domain and considering the gravity of the cooling medium, the flow channel volume fraction during optimization is reasonably controlled to obtain a plane liquid-cooling flow channel. The cylindrical flow channel is obtained by bending 360° with the mid-plane as the reference plane, thereby obtaining an electric spindle cooling jacket, which has better temperature uniformity and lower power consumption than traditional spiral flow channels.

[0005] To achieve the above object, the technical solution of the present invention is: a topology optimization design method for the liquid cooling channel of the electric spindle cooling jacket, the steps of which are:

[0006] Step 1: 2D planar flow channel topology optimization design

[0007] Considering the gravity of the cooling medium, controlling the volume fraction of the fluid channel, and based on the flow-heat coupling topology optimization design technology, the flow channel distribution morphology in the two-dimensional plane design domain is obtained;

[0008] Step 2: Construction of three-dimensional electric spindle cooling jacket

[0009] The two-dimensional flow channel profile distribution curve is extracted, and the flat liquid cooling plate is obtained by stretching modeling. Then, the liquid cooling plate is bent 360° with the mid-surface as the reference plane to obtain the three-dimensional cylindrical electric spindle cooling jacket flow channel structure.

[0010] In step 1, first, according to the cylindrical geometric features of the electric spindle and the actual structural dimensions of the electric spindle cooling jacket, the electric spindle cooling jacket is two-dimensionally unfolded to form a plane design domain, and the working medium inlet and outlet are determined; the design domain is a rectangle L×H with a certain aspect ratio, the inlet is arranged in the middle of the left side of the design domain, and the outlet is arranged at the upper and lower corners of the right side of the design domain, and the size of a single outlet is 1 / 2 of the inlet size;

[0011] In the process of topology optimization, the effect of gravity acceleration on the cooling medium is taken into account, and the control equation is:

[0012]

[0013] Where: u* is the dimensionless velocity; is the dimensionless gradient operator; p* is the dimensionless pressure; Re is the Reynolds number; ρ is the fluid density; λ is the design variable, which can be any value from 0 to 1; Da is the Darcy number; q is the penalty factor; G * is the dimensionless gravitational acceleration, defined as follows:

[0014]

[0015] Where: is the gravitational acceleration; L is the characteristic length; u is the flow velocity;

[0016] The direction of the gravitational acceleration added in the design domain is perpendicular to the two sides along the symmetry axis. The maximum heat exchange is taken as the optimization goal, and the volume fraction occupied by the fluid channel is controlled to be 0.65 to obtain the optimized distribution shape of the two-dimensional planar liquid cooling flow channel.

[0017] In step 2, first, extract the two-dimensional plane liquid cooling channel contour distribution line, stretch the model to obtain a plane liquid cooling plate, then, bend the liquid cooling plate 360° with the mid-surface as the reference plane to obtain a three-dimensional cylindrical electric spindle cooling jacket structure; finally, complete the water inlet and outlet structures to obtain the electric spindle cooling jacket.

[0018] The beneficial effects of the present invention are:

[0019] The present invention proposes a topology optimization design method for the liquid cooling channel of the electric spindle cooling jacket, which adopts two steps: 1. Considering the gravity of the cooling medium, controlling the volume fraction of the fluid channel, and obtaining the distribution form of the channel in the two-dimensional plane design domain based on the flow-heat coupling topology optimization design technology; 2. Extracting the two-dimensional channel contour distribution curve, stretching modeling to obtain a plane liquid cooling plate, and then bending the liquid cooling plate 360° with the mid-plane as the reference plane to obtain a three-dimensional cylindrical electric spindle cooling jacket channel structure. The three-dimensional cylindrical electric spindle cooling jacket channel structure has better temperature uniformity and lower power consumption than the traditional spiral channel.

[0020] The topological optimization design method proposed in the present invention takes into account the gravity of the cooling medium and controls the volume fraction of the liquid cooling channel. The designed electric spindle cooling sleeve has excellent performance, especially in terms of temperature uniformity, maximum temperature and pressure drop control, showing superior performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Design domain diagram for the plane;

[0022] Figure 2 It is the optimized distribution morphology diagram of the two-dimensional liquid cooling channel;

[0023] Figure 3 It is a flat liquid cooling plate;

[0024] Figure 4 It is the cooling jacket of the electric spindle;

[0025] Figure 5 A two-dimensional plane design domain diagram of a cooling jacket is generated from the geometric features of the electric spindle in the embodiment;

[0026] Figure 6 The cooling sleeve of the electric spindle in the embodiment;

[0027] Figure 7 For comparison, design 1-traditional spiral groove flow channel cooling jacket;

[0028] Figure 8 Design 2-dimensional planar liquid cooling channel optimized distribution morphology diagram for comparison;

[0029] Fig. 9 Design 2-Electric Spindle Cooling Jacket for Comparison. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] The present invention proposes a topology optimization design method for a liquid cooling channel of an electric spindle cooling jacket, comprising:

[0032] Step 1: 2D planar flow channel topology optimization design

[0033] First, according to the cylindrical geometric features of the electric spindle and the actual structural dimensions of the electric spindle cooling jacket, the electric spindle cooling jacket is two-dimensionally expanded to form a plane design domain and determine the working fluid inlet and outlet. Figure 1 As shown, the design domain is a rectangle L×H with a certain length-to-width ratio. The inlet is arranged in the middle of the left side of the design domain, and the outlet is arranged at the upper and lower corners of the right side of the design domain. The size of a single outlet is 1 / 2 of the size of the inlet.

[0034] Since there is a certain height difference between the inlet and outlet positions of the electric spindle cooling jacket, the gravity of the working fluid will affect the flow of the working fluid in the flow channel. Therefore, it is necessary to take into account the effect of gravity acceleration on the cooling working fluid during the topology optimization process, and the control equation is:

[0035]

[0036] Where: u* is the dimensionless velocity; is the dimensionless gradient operator; p* is the dimensionless pressure; Re is the Reynolds number; ρ is the fluid density; λ is the design variable, which can be any value from 0 to 1; Da is the Darcy number; q is the penalty factor; G * is the dimensionless gravitational acceleration, defined as follows:

[0037]

[0038] Where: is the gravitational acceleration; L is the characteristic length; u is the flow velocity.

[0039] The direction of the gravitational acceleration added in the design domain is perpendicular to the two sides along the symmetry axis, such as Figure 1 As shown in the figure, taking the maximum heat exchange as the optimization goal, the volume fraction of the fluid channel is controlled to be 0.65, and the optimized distribution shape of the two-dimensional plane liquid cooling flow channel is obtained, as shown in Figure 2 shown.

[0040] Step 2: 3D spindle cooling jacket construction

[0041] First, extract the contour distribution line of the two-dimensional liquid cooling channel and stretch the model to obtain the plane liquid cooling plate, such as Figure 3 As shown; then, the liquid cooling plate is bent 360° with the mid-surface as the reference plane to obtain a three-dimensional cylindrical electric spindle cooling jacket structure; finally, the water inlet and outlet structures are completed to obtain the electric spindle cooling jacket, as shown Figure 4 shown.

[0042] Application examples of the present invention:

[0043] The effectiveness of the present invention is illustrated by taking the design of the cooling jacket of a certain type of electric spindle as an example.

[0044] 1. Design requirements

[0045] The cooling jacket is designed to control the temperature uniformity in the effective area. The heat flux density on the electric spindle cooling jacket is 2.55kW / m 2 The outer diameter of the electric spindle is φ30mm, the length is 81mm, the cooling jacket material is aluminum 6061, and the cooling medium is deionized water.

[0046] 2. Optimization design of the cooling jacket structure of the electric spindle

[0047] According to the size of the electric spindle, the design cooling jacket flow channel height is 10mm, the wall thickness is 3mm, and the outer diameter of the electric spindle cooling jacket is φ62mm. Then its plane expansion is 81mm×195mm, and the two-dimensional plane design domain is 75mm×195mm. Figure 5 As shown in the figure, the volume fraction of the fluid channel is set to 0.65, the Reynolds number Re=300 is used, and the influence of the gravity acceleration of the fluid is considered. The topology optimization design is performed based on formula (1) to obtain the two-dimensional plane flow channel morphology distribution.

[0048] According to step 2, extract the curved contour line of the two-dimensional plane liquid cooling channel, stretch the model to obtain a plane liquid cooling plate, bend the liquid cooling plate 360° with the mid-surface as the reference plane to form a three-dimensional cylindrical shape, fill the water inlet and outlet structures, and obtain the electric spindle cooling jacket, such as Figure 6 Specific structural dimensions are shown.

[0049] 3. Analysis of heat and mass transfer performance of electric spindle cooling jacket

[0050] The cooling jacket is made of aluminum alloy 6061, the cooling medium is deionized water, the inner surface of the cylinder is a uniformly distributed heat source, the external environment is standard atmospheric pressure, the ambient temperature is 20°C, the water inlet temperature is constant at 20°C, and the cooling medium is set to a constant mass flow rate at the inlet. The properties of each material are shown in Table 1, where density ρ is the material density, C p is the specific heat, k is the thermal conductivity, and μ is the dynamic viscosity of the fluid.

[0051] Table 1 Physical properties of deionized water and aluminum 6061

[0052]

[0053] When Re = 1000, the maximum temperature of the inner surface of the cooling jacket is T max =29.7℃, temperature difference ΔT=9.7℃, pressure drop ΔP=208Pa.

[0054] As a comparative design 1, the volume fraction of the fluid channel is also 0.65. The conventional spiral groove flow channel cooling jacket is Figure 7 As shown, the simulation model is established under the same conditions. The simulation results show that the maximum temperature of the inner surface of the cooling jacket is T max =54.8℃, temperature difference ΔT=34.8℃, pressure drop ΔP=2386Pa.

[0055] As a comparative design 2 of the design example, when performing topological optimization design on the liquid cooling channel of the cooling jacket, the influence of the gravity acceleration of the fluid is not taken into account. Other conditions are the same, and the distribution of the two-dimensional plane channel is obtained, such as Figure 8 As shown; according to step 2, a three-dimensional model of the cooling jacket is established, as shown Fig. 9As shown; the simulation model is established under the same conditions, and the simulation results show that the maximum temperature T of the inner surface of the cooling jacket max =31.9℃, temperature difference ΔT=11.9℃, pressure drop ΔP=403Pa.

[0056] From the above, it can be seen that the topology optimization design method proposed in the present invention, which takes into account the gravity of the cooling medium and controls the volume fraction of the liquid cooling channel, has excellent performance in the designed electric spindle cooling jacket, especially in terms of temperature uniformity, maximum temperature and pressure drop control, showing superior performance.

[0057] The application example fully illustrates the effectiveness of the optimization design method proposed in the present invention.

Claims

1. A topology optimization design method for the liquid cooling channel of an electric spindle cooling jacket, characterized in that: The steps are: Step 1: 2D planar flow channel topology optimization design Considering the gravity of the cooling medium, controlling the volume fraction of the fluid channel, and based on the flow-heat coupling topology optimization design technology, the flow channel distribution in the two-dimensional plane design domain is obtained; firstly, according to the cylindrical geometric characteristics of the electric spindle and the actual structural size of the electric spindle cooling jacket, the electric spindle cooling jacket is two-dimensionally unfolded to form a plane design domain, and the working medium inlet and outlet are determined; the design domain is a rectangle L×H with a certain aspect ratio, the inlet is arranged in the middle of the left side of the design domain, and the outlet is arranged at the upper and lower corners of the right side of the design domain, and the size of a single outlet is 1 / 2 of the inlet size; In the process of topology optimization, the effect of gravity acceleration on the cooling medium is taken into account, and the control equation is: Where: u* is the dimensionless velocity; is the dimensionless gradient operator; p* is the dimensionless pressure; Re is the Reynolds number; ρ is the fluid density; λ is the design variable, which can be any value from 0 to 1; Da is the Darcy number; q is the penalty factor; G * is the dimensionless gravitational acceleration, defined as follows: Where: is the acceleration due to gravity; L is the characteristic length; u is the flow velocity; The direction of the gravitational acceleration added in the design domain is perpendicular to the two sides along the symmetry axis. The maximum heat exchange is taken as the optimization goal, and the volume fraction of the fluid channel is controlled to be 0.65 to obtain the optimized distribution shape of the two-dimensional plane liquid cooling flow channel. Step 2: Construction of three-dimensional electric spindle cooling jacket The two-dimensional flow channel profile distribution curve is extracted, and the flat liquid cooling plate is obtained by stretching modeling. Then, the liquid cooling plate is bent 360° with the mid-surface as the reference plane to obtain the three-dimensional cylindrical electric spindle cooling jacket flow channel structure.

2. The topology optimization design method of the liquid cooling channel of the electric spindle cooling jacket according to claim 1 is characterized in that: In step 2, first, extract the two-dimensional plane liquid cooling channel contour distribution line, stretch the model to obtain a plane liquid cooling plate, then, bend the liquid cooling plate 360° with the mid-surface as the reference plane to obtain a three-dimensional cylindrical electric spindle cooling jacket structure; finally, complete the water inlet and outlet structures to obtain the electric spindle cooling jacket.

Images