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Simple Conduction Example using Ansys


Introduction

This tutorial was created using ANSYS 7.0 to solve a simple conduction problem.
The Simple Conduction Example is constrained as shown in the following figure. Thermal conductivity (k) of the material is 10 W/m*C and the block is assumed to be infinitely long.

Preprocessing: Defining the Problem

  1. Give example a Title
  2. Open preprocessor menuANSYS Main Menu > Preprocessor
    /PREP7
  3. Create geometryPreprocessor > Modeling > Create > Areas > Rectangle > By 2 Corners > X=0, Y=0, Width=1, Height=1
    BLC4,0,0,1,1
  4. Define the Type of Element
  5. Preprocessor > Element Type > Add/Edit/Delete... > click 'Add' > Select Thermal Mass Solid, Quad 4Node 55
    ET,1,PLANE55
    For this example, we will use PLANE55 (Thermal Solid, Quad 4node 55). This element has 4 nodes and a single DOF (temperature) at each node. PLANE55 can only be used for 2 dimensional steady-state or transient thermal analysis.

  6. Element Material Properties
  7. Preprocessor > Material Props > Material Models > Thermal > Conductivity > Isotropic > KXX = 10 (Thermal conductivity)
    MP,KXX,1,10

  8. Mesh Size
  9. Preprocessor > Meshing > Size Cntrls > ManualSize > Areas > All Areas > 0.05
    AESIZE,ALL,0.05

  10. Mesh
  11. Preprocessor > Meshing > Mesh > Areas > Free > Pick All
    AMESH,ALL

Solution Phase: Assigning Loads and Solving


  1. Define Analysis Type
  2. Solution > Analysis Type > New Analysis > Steady-State
    ANTYPE,0

  3. Apply Constraints
  4. For thermal problems, constraints can be in the form of Temperature, Heat Flow, Convection, Heat Flux, Heat Generation, or Radiation. In this example, all 4 sides of the block have fixed temperatures.

    • Solution > Define Loads > Apply
      Note that all of the -Structural- options cannot be selected. This is due to the type of element (PLANE55) selected.
    • Thermal > Temperature > On Nodes
    • Click the Box option (shown below) and draw a box around the nodes on the top line.
      The following window will appear:

    • Fill the window in as shown to constrain the side to a constant temperature of 500
    • Using the same method, constrain the remaining 3 sides to a constant value of 100Orange triangles in the graphics window indicate the temperature contraints.

  5. Solve the System
  6. Solution > Solve > Current LS
    SOLVE

Postprocessing: Viewing the Results


  1. Results Using ANSYS
  2. Plot Temperature
    General Postproc > Plot Results > Contour Plot > Nodal Solu ... > DOF solution, Temperature TEMP
    Note that due to the manner in which the boundary contitions were applied, the top corners are held at a temperature of 100. Recall that the nodes on the top of the plate were constrained first, followed by the side and bottom constraints. The top corner nodes were therefore first constrained at 500C, then 'overwritten' when the side constraints were applied. Decreasing the mesh size can minimize this effect, however, one must be aware of the limitations in the results at the corners.

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