Velocity of mist droplets and suspending gas imaged separately

► Velocity of gas and velocity of droplets in mist imaged separately. ► In upward pipe flow droplets clearly have slower velocity. ► In horizontal flow mist flows along bottom of pipe, driven by gravity. ► Magnetic resonance imaging overcomes optical opacity and measures velocity of both phases. ► Dynamics of how particle size varies with flow geometry revealed by comparison with multi-stage aerosol impactor.