Nowadays boiling phenomenon has been an important issue in various fields such as petroleum industries and nuclear power plants due to enhancement of the total heat transfer coefficient. One method to increase the level of heat transfer coefficient is to add certain nanoparticles such as 〖Al〗_2 O_3 to the base fluid. The present paper concerns the effect of nanoparticles on forced convective boiling within the general- purpose computational fluid dynamics (CFD) solver FLUENT. The governing equations solved are generalized phase continuity, momentum and energy equations. Wall boiling phenomena are modeled using the baseline mechanistic nucleate boiling model developed in Rensselaer Polytechnic Institute (RPI). To simulate the critical heat flux phenomenon, the RPI model is extended to the departure from nucleate boiling by partitioning wall heat flux to both liquid and vapor phases considering the existence of thin liquid wall film. In addition to validating the subcooled boiling phenomenon, the effect of aluminum oxide 〖Al〗_2 O_3 nanoparticles on heat transfer coefficients has been analyzed. It is concluded that by increasing the volume fraction of 〖Al〗_2 O_3 nanoparticles in the base fluid, wall temperature has been dropped and the heat transfer coefficients have been increased significantly.