The degree of gas convection can be characterised by the Rayleigh number (Re)and the degree of heat-transfer by gas convection can be characterised by Nusselt number( Nu ) in the crystal growth of oxides by means of CZ method.
引上法生长高温氧化物晶体时，热腔中的气体对流状态由雷诺数（Ｒｅ）决定，气体对流传热由努赛尔数（Ｎｕ）决定。