Magnetic susceptibility based magnetic resonance estimation of micro-bubble size for the vertically upward bubbly flow

► Fast dispersion (diffusion) in bubbly flows enables extraction of bubble size with magnetic resonance. ► Strong bubble-induced changes in T2∗ require short encoding times. ► Approach is reliable for micro-bubbles and slow flow rates. ► Approach underestimates sizes of interacting bubbles at faster flow rates.