Bubble departure diameter has significant effect on bubble dynamics and heat transfer in boiling system, and it is difficult to be measured in a boiling system. Therefore, a method to predict bubble departure diameter is necessary to study of bubble dynamics and heat transfer in boiling system. A new theoretical model based on force analysis is proposed for the prediction of bubble departure diameter in vertical boiling system in this paper. Surface tension force, unsteady drag force, quasi-steady drag force, shear lift force, buoyancy force, hydrodynamic pressure force and contact pressure force are taken into account to build the model. Chen’s experimental data is used to validate the model, the averaged relative deviation between the predict results of the model and the experimental data is less than ±14.8%.
