This article presents a new computational two-phase flow model and extensive validation for an industrial splash plate nozzle. The primary motivation for this work was to develop a simulation tool that can be used to reliably calculate initial droplet velocity data of industrial spray nozzles. This is an important part in properly defining boundary conditions for CFD furnace combustion simulations, for example, in the case of a recovery boiler burning black liquor. The model will also be actively used later for the industrial engineering and design of black liquor nozzle development. The model can also be used for other liquid fuels sprayed under flashing and nonflashing conditions. The model is based on the numerical solution of one-dimensional conservation equations of mass, momentum, energy, steam mass fraction, and bubble number density by using state of the art numerical methods that can track all the relevant mechanisms. Mass-momentum coupling was solved by the SIMPLE method. Scalar equations were solved by the fully implicit control volume method. A totally new and computationally efficient single-equation vapor generation source model was developed including heat transfer to bubble surface, evaporation, and inertial, viscous, and surface tension forces. Non-Newtonian effects were also included. The article presents comparison data for real flashing conditions with industrial black liquor, validating also the model predictions for initial spray velocity, nozzle pressure loss, and mass flow rate.