Аннотация:Safe operation of orbital platforms relies heavily on stability of fluid flows in microgravity. The inherent instability of two-phase flows under microgravity conditions could be a threat to fluid transporting equipment operation in Space thus altering Space flight safety conditions. The paper considers a multiphase flow in a Hele-Shaw cell. A dimensionless criterion characterizing the flow in such cells is described. If one changes the parameters of the experiment in such a way that the dimensionless criterion retains its value, then one can observe similar processes in microgravity and in terrestrial gravity. The paper describes the results of experiments on the flow in a Hele-Shaw cell in microgravity during parabolic flights, as well as laboratory experiments in normal gravity. It is shown that the generally accepted mathematical model used to model flows in the Hele-Shaw cell is not suitable for describing multiphase flows. A modified semi-empirical mathematical model is proposed, which gives a satisfactory coincidence of the experimental data with the analytical solution. Non-linear analysis of three fluids displacing each other is performed demonstrating the growth of viscous fingers on both interfaces and their interactions