On introduction of gravitational acceleration into the calculation of length and velocity scales, a set of dimensionless parameters appears in the mathematical model which enable the behaviour of convection and heat and mass transfer under changing gravitational conditions to be predicted. By directly simulating the equations of motion and heat transfer, the effectiveness of the proposed formulation of conservation laws in treating such phenomena in liquids is demonstrated for both isothermal and non-isothermal cases and under both terrestrial and space conditions.