Direct steam generation in parabolic-trough solar collectors has been under evaluation in recent years for its technical feasibility, process control and cost. Knowledge of the dynamic behavior of such system is particularly important as changes in inlet water conditions or in the solar radiation affect the amount of steam generated in the solar field. The process must therefore be controlled to ensure constant quality of produced steam. This work introduces a computational fluid dynamic simulation approach to predict the behavior of a solar steam generating system, which is located at the Plataforma Solar de Almeria, Spain. The STAR-CCM+ code has been used to implement an efficient multiphase model capable of simulating the dynamics of the multiphase fluid in parabolic-trough solar collectors. Numerical and experimental data are compared in a wide range of working conditions. (C) 2013 Elsevier Ltd. All rights reserved.