Flashing flow is a common phenomenon in many industrial applications and, in steam-assisted gravity drainage (SAGD), it is considered a significant process. Flashing may occur if there is a sudden pressure drop in the production well in SAGD, which is a typical in-situ way to extract heavy oil from tar sands. This may change the expected pressure drop across inflow control devices (ICDs), which are the controllers installed within the production well. Flashing is defined as self-boiling of a liquid due to a reduction of pressure, and it is a complex, multiphase flow phenomenon. The main objectives of the present work are to develop and to validate a multiphase computational model that has the ability to predict the thermo-fluid behaviour of the flow during the flashing process inside ICD nozzles, and to assess its effect on the pressure distribution through ICDs in a predictive way. Our computational model is applied to time-averaged, two-phase, adiabatic, turbulent flows. The new computational model can predict the phase changes between liquid and vapour phases based on mechanical effects (pressure). This is achieved by comparing the local pressure in each computational cell with the local vapour pressure. Considering the thermo-fluid complexity together in one model gives such a simulation the potential to be invaluable for a better understanding of roles of the combined mass transfer and the flashing dynamics during the flashing flow process, and to be applied as an industrial inflow control device to choke back steam for SAGD production system. It may assist in obtaining insight and information where measurements would be difficult. Furthermore, the CFD results can be used to generate compact predictive functions of pressure drop within ICDs, and to investigate the effects of both non-condensable gases and solvents in ICDs performance.