This is a model of the internal chamber of a oven, the reason of the simulation is to show when the chamber got a temperature by 573 K, on this case y have a internal fan ( figure like a wheel), a inlet flow volumen that hava Temperature of 900 K, also I have a heat source with the same temperature of  900K, I put a radiactive surface and decide to use the half part of the oven as the computanional domain in order to have less iteration time

Thoose are my mesh settings and a level 1 and my calculation settings 

The iteration time have the order of 39900 minutes, i´m looking for a way to mesh in order to have less iteration time 

Thansk