Thanks, sir. see the attachment. We will increase or decrease the values of these parameters and will check the effect of temperature and velocity profiles.
Shahid, what is actually your problem with ANSYS Fluent? The software package successfully handles the problem you wish to solve, therefore you can successively change the parameters you wish.
I think first you need to solve natural convection problem neglecting radiation effects. Secondly solve the problem considering Heat source and validate your results and then incorporate MHD effects and other described by your problem. In ANSYS, the values cannot be directly given for dimensionless numbers. You need to fix some parameter and later change some other parameters to change Ra and same applies for other cases as well.