icepak-meshing-网格划分

Re-
No
examine
来自百度文库
the Mesh
OKY?es
Solve
Examine mesh using 物体的surface plots and cut planes use x,y,z count 对物体进行划分 设定物体周围的Low and High element size/ratio Inward height/ratio to refine within an object set Max X, Y, Z sizes
E-4
Meshing steps and considerations
default options with Max X,Y,Z set to 1/10th or 1/20th of
domain size
Examine the Mesh
Refine the Mesh
Generate new Mesh
E-3
Automatic meshing
• All the methods are fully automated • 可以进行不同复杂程度的网格划分
No parameters set Parameters defined on an object by object basis • After meshing, Icepak checks the key quality measure.If there are cells with poor quality, Icepak will automatically display them. • The Key measures are: • Face Alignment for Hexahedral(面扭曲率) • Aspect Ratio for Tetrahedral(长宽比)
Coarse Mesher – ▪ Provides a coarse mesh
Mesher default settings include: ▪ Min elements in fluid gap - Minimum number of cells in between adjacent faces
Max Size ratio • Between 2 and 10
Max “O” grid height • Default setting of 0 means that there is no control of the height of the cut-out region • Recommended to set a reasonable “O”-grid height
E-6
Hexahedral meshing
结构化网格
非结构化网格
• 台阶状近似几何 • 不正确的几何面积 • 远场网格不得不加密 • 网格数量多，精度差
E-7
• 真实几何 • 正确的几何面积 • 只在需要的地方加密网格 • 网格数量少，精度好
Hexahedral meshing:structured and unstructured
• Mesh assemblies separately 选择它， Icepak 将对assemblies创建 non-conformal and put a finer mesh on the objects within the assembly
E-14
Recommendations
Min elements in fluid gap • Either 2 or 3 • More than 4 may refine the mesh in unwanted regions
E-20
Viewing the mesh
Display mesh: surface/ volume/ solid/ cut plane options Cut plane location/ mesh color
E-19
Per-object parameters: Circular geometry
Circular Cylindrical Objects - e.g. 汽缸etc… • Additional settings are: Diameter count Side count – Number of elements along the curved surface of the cylinder 等等
E-8
Hexahedral meshing: Generation panel
包括 generate, Display, Check quality, and Export
Default Settings mesher type, background mesh settings
Global Settings for refining mesh
E-16
Per-object parameters: Rectangular geometry
Rectangular Prism objects - e.g.: Block/Resistance • X,Y,Z count • Low/High X,Y,Z height 第一个网格的高度 away from and object • Low/High X,Y,Z ratio Growth of aspect ratio away from an object • Inward height/ratio Height/growth of first cell into an object
Object Params • Individual parameters
E-10
Recommendations
Max X, Y, Z • By default this is 1/20th of the cabinet dimensions • 1/10th of the domain size is sufficient for a coarse grid • 不推荐使用小于1/20th domain size,可能生成大量不必 要的网格
Init Height • Recommended that you do not set this on large models as it can result in very large mesh counts
E-11
Global settings (1)
Normal Mesher – ▪ Provides an acceptable mesh for most situations
▪ Max O-grid height - Maximum height of the O-grid region from the surface of an object
E-12
Global settings (2)
Maximum Size Ratio • 可以控制网格尺寸的增长速度 • The Growth ratio of elements away from surfaces can be controlled using this setting. Dx2 / Dx1 < Max size Ratio setting
E-2
Icepak automatic meshing: Overview
•Two Hexahedral meshers Unstructured Cartesian
•Tetrahedral mesher 专门使用于 some complex geometry Must be used for ellipsoids, elliptical cylinders, or polygonal ducting
E-17
Per-object parameters: Rectangular geometry
Rectangular planar objects - e.g. Rectangular vent, PCB, Plate etc... • X&Y, Y&Z, X&Z count • Low/High end height Height of first cell either side of planar object • Low/High end ratio growth rate either side of object • Inward height/ratio Height/growth of cells into the object
5. Meshing
Meshing
E-1
Icepak automatic meshing: Overview
先进的网格技术
➢ Fully automatic 完全自动化的网格生成 ➢ Local and global controls 局部和总体控制 ➢ Hexahedral or Tetrahedral meshes 六面体/四面体 ➢ 先进的非结构化网格 ➢ 先进的non-conformal mesh
E-18
Per-object parameters: Circular geometry
圆板 objects - e.g. fan etc… • Additional settings are: Diameter count – Number of cells across the diameter Low/High End heights and ratios
• Use coarse mesh for initial solutions • Use suitably refined mesh for final solution
E-5
Hexahedral meshing
Two Hexahedral Meshers Unstructured - Mesh will follow the geometry Cartesian - 六面体单元组成的structured mesh - 对非矩形几何模型划分Stair-step(阶梯状) approximations
E-15
Using per-object parameters
可以对指定的物体设置网格参数. • Uses include: Controlling the mesh density around objects 以捕 捉 thermal/flow gradients
Enter a requested value • Note: 细画时: – Mesh count must be greater than current value – Heights or ratios must be less than current value
E-9
Default settings
Mesher Type • Hexa-Unstructured, Hexa-Cartesian, Tetrahedral,mesher-hd(hexdominant mesher六面体核心网格) • 只有六面体核心网格才能对CAD objects进行网格划分
Max X, Max Y, Max Z • Control the size of the largest cell allowable in the background mesh
Solid region
Fluid Region
Dx1 Dx2 Dx3
E-13
Global settings (3)
Min elements on cylinder face Min elements on triangle face Additional Optional Flags
• No “O” grid Prevents “O” meshing on all objects
Min elements in fluid gap = 2
Min elements in fluid gap = 3
▪ Min elements on solid edge - Minimum number of cells to be placed on the edge of an object