Prediction model for annular flow in vertical narrow annular gap

This paper analyses the theoretical model for annular flow boiling heat transfer in vertical narrow annular channel and develops a mathematical model on the base of the mass, momentum and energy conversation equations of liquid film, as well the momentum equation of vapor core. Liquid film thickness, radial velocity and temperature distribution in liquid film, heat transfer coefficient of inner and outer walls and axial pressure gradient can be obtained by numerically solving the equations. The comparison between predicted results and experimental data shows that they meet each other well. This confirms the rationality of the prediction model for annular flow in narrow annular channel.