How to conduct Natural Convection analysis for Fin
 

Hello.....
I am simulating natural convection analysis for base plate (250mm x 250mm) having fins. Please see the attached images. Here atmospheric temperature is 27 C and heat flux for the plate with fin is 332 w/m2 ( Surafce area of plate with fin= 0.3155 m2 and Heat transfer rate Q= 105 W) . If we are considering the atmospheric heat transfer coefficient upto 5 W/m2K then as per Newtons law of cooling (Q= h. A. (Ts- Tatm)), Surface temperature of plate with fin will go upto 94 C.
Here I am simulating the case with different boundary conditions like opening boundary conditions at all walls of fluid domain, very smaller inlet velocity (0.05 m/s), free slip boundary conditions at side wall of fluid domain. Here buoyancy model has activated with gravity -9.81 m/s2 as well ref. temperature of 27 C and laminar model is considered. But I am getting areave temperature at fin wall maximum upto 44 C.
Here, what boundary conditions I have to use so that I will get fin temperature upto 93 C.

Please help me. Thanks in advance.

Read the FAQ: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

There are MANY things to get right before you have an accurate simulation. You need to get ALL the things mentioned in the FAQ under control to be accurate (not just the easy ones like some people seem to think :) ). In you case I can already see the outer boundaries are too close to the region of interest. But there are bound to be other problems as well.