Learning Forum

[nhossain]

Dear Sir:

I am doing a thermal simulation of a composite wall. I am using "Thermal Element (PLANE55)", which is available in ANSYS 18. The left side has fixed Temperature of 200 degree C. The right side has "Convection".

I am interested to calculate the "heat" that is required to maintain "200 degree C" at the "Left Side". So, I selected the nodes where "Boundary Condition" was applied. Then, I am using "PRNLD, Heat" command. It offers me "Total Heat". However, it comes with a "Negative Sign".

What is the physical meaning of this "Negative Sign"? Is it related to "Thermal Equilibrium". Could you explain. I am also attaching my code. Many, many thanks,

Awlad.

Composite_Wall_Thermal_Simulation.txt

[dlooman]

The boundary condition is adding heat to the model so PRRSOL gives positive heat flows. The elements are pulling heat out of the boundary condition so PRNLD,HEAT values are negative. This produces thermal equilibrium at the constrained nodes, zero net heat flow for a steady state solution. n

[dlooman]

Use FSUM to get the total heat flow.n