Time difference

I am interesting in natural convection simulation. I have a problem of validation my COMSOL model where the time in the literature case differs from my model time . In another words, when I try to compare the same case in literature where the time of reaching steady state is 1000 s, but the model may be reaches the the same result in the 223 s.
I am very grateful for any reply for this difference.

Thanks,


Nabeel