Step 6: Boundary Conditions

Boundary Conditions

1.   Set the boundary conditions for the inlet ( inlet).

Boundary Conditions inlet Edit...

(a)   Enter 0.00101 ${\rm m/s}$ for Velocity Magnitude.

(b)   Click the Thermal tab and enter 1300 ${\rm K}$ for Temperature.

(c)   Click OK to close the Velocity Inlet dialog box.

2.   Set the boundary conditions for the outlet ( outlet).

Boundary Conditions outlet Edit...

  Here, the solid is pulled out with a specified velocity, so a velocity inlet boundary condition is used with a positive axial velocity component.

(a)   Select Components from the Velocity Specification Method drop-down list.

  The Velocity Inlet dialog box will change to show related inputs.

(b)   Enter 0.001 ${\rm m/s}$ for Axial-Velocity.

(c)   Enter 1 ${\rm rad/s}$ for Swirl Angular Velocity.

(d)   Click the Thermal tab and enter 500 ${\rm K}$ for Temperature.

(e)   Click OK to close the Velocity Inlet dialog box.

3.   Set the boundary conditions for the bottom wall ( bottom-wall).

Boundary Conditions bottom-wall Edit...

(a)   Click the Thermal tab.

i.   Select Temperature from the Thermal Conditions group box.

ii.   Enter 1300 ${\rm K}$ for Temperature.

(b)   Click OK to close the Wall dialog box.

4.   Set the boundary conditions for the free surface ( free-surface).

Boundary Conditions free-surface Edit...

  The specified shear and Marangoni stress boundary conditions are useful in modeling situations in which the shear stress (rather than the motion of the fluid) is known. A free surface condition is an example of such a situation. In this case, the convection is driven by the Marangoni stress and the shear stress is dependent on the surface tension, which is a function of temperature.

(a)   Select Marangoni Stress from the Shear Condition group box.

  The Marangoni Stress condition allows you to specify the gradient of the surface tension with respect to temperature at a wall boundary.

(b)   Enter -0.00036 ${\rm n/m-k}$ for Surface Tension Gradient.

(c)   Click the Thermal tab to specify the thermal conditions.

i.   Select Convection from the Thermal Conditions group box.

ii.   Enter 100 ${\rm w/m}^2{\rm -k}$ for Heat Transfer Coefficient.

iii.   Enter 1500 ${\rm K}$ for Free Stream Temperature.

(d)   Click OK to close the Wall dialog box.

5.   Set the boundary conditions for the side wall ( side-wall).

Boundary Conditions side-wall Edit...

(a)   Click the Thermal tab.

i.   Select Temperature from the Thermal Conditions group box.

ii.   Enter 1400 ${\rm K}$ for the Temperature.

(b)   Click OK to close the Wall dialog box.

6.   Set the boundary conditions for the solid wall ( solid-wall).

Boundary Conditions solid-wall Edit...

(a)   Select Moving Wall from the Wall Motion group box.

  The Wall dialog box will expand to show additional parameters.

(b)   Select Rotational in the lower box of the Motion group box.

  The Wall dialog box will change to show the rotational speed.

(c)   Enter 1.0 ${\rm rad/s}$ for Speed.

(d)   Click the Thermal tab to specify the thermal conditions.

i.   Select Temperature from the Thermal Conditions selection list.

ii.   Enter 500 ${\rm K}$ for Temperature.

(e)   Click OK to close the Wall dialog box.