Numerical modelling of velocity and temperature fields in high-temperature KNbO3 melt of a loop-shaped Ptwire heater is carried out by using the commercial computational code ANSYS for the mathematical solution ofthe goveing equations. Based on the experimental boundary conditions and the Boussinesq approximation, thenumerical modelling ofa steady and two-dimensional model is applied to study the process under consideration ofthe buoyancy-driven convection condition. The result is compared with the previous experimental and theoreticaldata obtained in our laboratory, and the former is in agreement with the latter. Thus a theoretical gnide forreasonable growth conditions is provided by studying in depth the real fluid flow effects in the crystal growthfrom the melt.