Thermal analisys for a natural convection model

[a.montes]

Hi,

I want know what is the correct model simulation for check the maximun temperature in a solid in a natural convection simulation? I made two simulation with two diferent method, a simulation without enclosure, with a convection factor calculated by iteration; and the other simulation, with enclosure (sometimes, appear the option to set the convection factor).

The simulation result´s are diferent betwen both simulation, and I don´t understand what is the reason. 

 

I add some pictures to show each case. Best regards.

[Deepak]

It'll be better to ask in the Fluids channel.

 

[Rob]

But as a brief answer. If you assume a solid-fluid HTC you can model the solid only. If you include the enclosure (and mesh it well enough etc) the heat transfer between fluid and solid is a function of the flow and temperature: ie it's a more accurate model.