Simulations and measurements of gas-droplet multiphase flows in application to supersonic expansions into vacuum have been considered and compared with each other. The experiments involved exposing a control surface to a supersonic plume from two different nozzles and measuring the size distribution of droplets at various locations. The simulations are based on the direct simulation Monte Carlo modeling of vapor-phase flow with a one-way coupling of droplet momentum and energy. The droplet trajectories are computed for the experimental conditions for droplets originating at the throat and lip of two different nozzles. The maximum droplet radius reaching the control surface and the variation of droplet size with angle predicted by the trajectory computations agree well with the measurements using Optical Microscopy
