ANSYSCFX2础训练课程5.pptVIP

* * * * * * * * * * * * * * * * * * * * WS6: Electronics Cooling WS6-* ANSYS, Inc. Proprietary ? 2009 ANSYS, Inc. All rights reserved. April 28, 2009 Inventory #002599 Workshop Supplement WS6-* ANSYS, Inc. Proprietary ? 2009 ANSYS, Inc. All rights reserved. April 28, 2009 Inventory #002599 Introduction to CFX Electronics Cooling withNatural Convection and Radiation This workshop models the heat dissipation from a hot electronics component fitted to a printed circuit board (PCB) via a finned heat sink. The PCB is fitted into a casing, which is open at the top and bottom. Initially only the heat transfer via convection and conduction will be modelled. The effect of thermal radiation will then be included at a later stage. Goals Loading Mesh (Workbench) Open a new Workbench project and save it as HeatSink.wbpj Look in the Component Systems section of the toolbox and drag a CFX system onto the Project Schematic Double-click Setup to start CFX-Pre In CFX-Pre, right-click Mesh and select Import Mesh ANSYS Meshing Select HeatSink.cmdb and click Open Options In the tree expand Case Options, double-click General and ensure that Automatic Default Domains is switched on and Automatic Default Interfaces is active. Set the Interface Method to One Per Domain Pair. Click OK. Separate interfaces are required for each domain because when radiation is added, emissivity will be set differently at each domain interfaces First add a domain for the fluid region. The effects of buoyancy must be included, as the flow is driven by natural convection. The buoyancy reference density represents the density at the ambient conditions. Right-click on Flow Analysis 1 and insert a new domain named Fluid Open the details for Fluid and set the Location to Fluid Set the Material to Air Ideal Gas Switch the Buoyancy option to Buoyant and set the directional components to (0, -g, 0) Click on the expression button to enter –g Set the Reference Density to 1.1093 [kg m^-3] Click the Fluid Mo