icepak-06-nonconformal.ppt

Non-Conformal Meshing A non-conformal mesh is one where there is transition from many cells to one cell In Icepak, assemblies of objects can be meshed non-conformally A “slack” or envelope can be defined around a particular assembly and the resulting region is meshed independent of the mesh outside This enables embedding a fine mesh within the assembly sub-region without leading to cell bleeding, while the model outside the assembly has a course mesh Non-Conformal meshing - Assembly The first thing to do is to edit the assembly, and turn on the option to mesh separately. Next, add a “slack” region around the assembly By default the bounding box of the assembly is the min/max extents of the objects making up the component Slack region allows the user to re-define the bounding box, to make it slightly larger than the objects making up the component. Assembly – defining slack The assembly bounding box must have sufficient slack so that its sides do not touch any Icepak object Cabinet, walls and hollow block are the only objects that may touch the sides of a non-conformally meshed assembly All objects except conducting thin plates and hollow blocks can intersect an non-conformal assembly – the portion within will be meshed non-conformally Any object can lie completely within the non-conformal assembly even though it may not be a part of the assembly Rules for non-conformal meshing (1) For example, in this model a 1U heat sink design is modelled as an assembly By default the bounding box would be the the size of the base in the x-z dimensions, and extend to the top of the fan casing. Where the fins touch the default bounding box, there would be a solid cell on the internal side of the interface, and a fluid side on the outside of the interface - this is currently not allowed by the solver Adequate slack must be specified, as in the figure below, so that the assembly bounding box does not touch the heat sink fins After specifying the slack the assembly can cut throug