SINOPSIS

We present a numerical model enabling us to study the mineralizer-mediated species transport during crystal growth in an ammonothermal autoclave. Special to our application is the presence of two transport channels where both channels have to be efficient in order to obtain high growth rates. We find that the contributions of both, thermal and solutal buoyancy, are important and hence the species transport efficiency cannot be estimated from flow pattern alone but has to be studied using reasonable transport mechanisms.