Numerical simulation of flow and mass transfer during the process of large-sized cuboid KDP crystals grown by the LSLM

•Flow and mass transfer in the cuboid KDP crystals grown by LSLM was studied.•Spatio-temporal evolution of the flow and supersaturation fields was presented.•Supersaturation field on the crystal face at various factors was analyzed.•Map of the relative strengths of natural and forced convections was summered.•Convective mass transfer regime was revealed. The growth of high-quality large-sized KDP crystals is to meet the requirements of high-power laser systems. The convective transport characteristics of KDP solution are one of the key factors affecting the growth of large-sized KDP crystals in the growth vessel. In this work, the three-dimensional simulation of flow and mass transfer occurring in the process of large-sized cuboid potassium dihydrogen phosphate (KDP) grown by the long seed limitation method (LSLM) has been performed employing the finite element method. The standard k-ε model with the enhanced wall treatment is used to calculate the turbulence flow in the growth vessel. The temporal and spatial evolution of flow field near the crystal face and supersaturation field on the crystal face during the growth is discussed in detail. The time-averaged supersaturation field on the crystal face at various factors is analyzed. The relative strengths of natural and forced convections on different conditions is compared, the convective mass transfer regime at different conditions is revealed.