CosmosWorks Conduction-Convection ExampleCOSMOSWorks传导对流的例子.docVIP

Local Singularity Conduction Convection Example (draft 2 12/3/05) Introduction A hot duct work consists of thin aluminum square tube that is 1.2192 m (4 ft). on each side that contains a hot gas at 298.9 C (570 F) and is surrounded with a layer of insulating fiberglass that has an outer radius of 1.2192 m (4 ft). The insulation material has a thermal conductivity of K = 3.462e-2 W/m C (0.020 BTU/hr ft F). The duct is surrounded by free air convection having a convection coefficient of h = 408.8 W/m^2 C (72.0 BTU/hr ft^2 F) and the air is at 23.9 C (75 F). Assume the aluminum is so thin that it causes the same temperature on the inter-most square surface of the insulation. Use CosmosWorks to determine the maximum surface temperature of the duct outer surface and the distribution of the internal heat flux vectors. For a typical duct unit length of 1 m (3.281 ft) estimate how much heat flows into the air. Note that the square duct causes a re-entrant corner in the insulation. Thus, there will be a local singularity in the temperature gradient at that point. SolidWorks Geometric model First select the working units (and dual dimension display): Use Tools(Options(Document Properties(Units Set Unit System to meters, and Dual units to feet, OK Use Tools(Options(System Options(Detailing In Dimensioning standard turn on Dual dimension display, OK The problem has a one-eight symmetry, so model the first 45 degree segment. Use Top(Insert Sketch Insert a 0 and 45 degree construction line Place and dimension the (insulation-air) arc Place and dimension the vertical (aluminum) line Connect the remaining two symmetry lines, as in Figure 1. Select Extruded Boss/Base (Figure 2). In the Extrude panel set distance D1 to 1 m, and method to Blind, OK Figure 1 Sketch for the part extrusion Figure 2 Extrusion of insulation material CosmosWorks model After saving the extruded part you are ready to move to the CosmosWorks option. Pick the CosmosWorks icon to a