Learning Forum

[HCR_student]

Hi all, does anyone know about the influence of the initial temperature setting in ansys - steady state thermal analysis? 

Below is a brief summary of my project and the settings that I have done:

My analysis is about the window frame, where the one outer face is exposed to the outdoor environment at 36.4 degree celsius and another is exposed to the indoor environment at 25 degree celsius. Convection setting is applied to both faces with (outside environment) free convection to air at 36.4 degrees C (5 W/m^2-K), and (indoor environment) forced convection at low speed of airflow over the surface (10 W/m^2-K) at 25 degree Celsius. 

However, there is an initial temperature setting. As I already have all my temperature setting down, what value should I base this initial temperature setting on? 

I understand that from the ansys help section:

This uniform temperature is used during the first iteration of a solution - to evaluate temperature-dependent material properties and it is also the starting temperature value for constant temperature loads. 

Please help!!

[Karthik Remella]

Hello,

Specifying an initial temperature allows the solver to use these temperature values as the starting values in your simulation. This is the temperature of your computational domain. The solver uses these values to start computing for a steady-state solution.

To understand this, please provide some additional details about the physical problem you are trying to solve.

Best,

Karthik

[HCR_student]

Thank you so much for your help.

I am working on a project to evaluate the thermal flow through a window frame. The aim of my project is to increase the thermal efficiency of the window frame by decreasing the thermal conductivity, where the air chamber parameters in the frame are able to reduce the amount of heat from the outside face from escaping into the room (inside face). 

Thus, my analysis is to show the flow of the heat through the window with the settings stated in the post above.

Below is a figure for reference. 

However, I have solved this analysis without changing the default setting of initial temperature (22degree celcius) as I am unsure of what temperature I should set it at.  

[Karthik Remella]

Hello,

Yes, it is possible that 22 degs might be an appropriate temperature. One way to understand the initial temperature would be to think about it in terms of a transient problem. In your physical problem, if you are trying to calculate the heat transfer from this window, what would be your initial conditions (at t = 0)?

If I were to draw an analogy: if I were holding an iron rod and heating this in the fire to calculate the net heat transfer. In the beginning, this iron rod is at room temperature. When one end is heated in the fire, the temperature at this end will start to rise. In order to simulate this heat transfer to a human hand, which is holding the rod, you will need to assume that the initial temperature is equal to the room temperature. Of course, you will need to impose other boundary conditions to be able to solve this problem to a steady-state solution. Again, this is just an example/analogy to help understand the concept of initial temperature.

I hope this helps.

Best Regards,

Karthik

[HCR_student]

Thank you so much!!!