Hydrodynamic and heat transfer analysis of two-phase annular flow with a new liquid film model of turbulence

Abstract A new method is presented for the analysis of hydrodynamics and heat transfer of two-phase annular flows with turbulent liquid films. Based on the experimental observation, the liquid film in two-phase annular flow is divided into a continuous layer adjacent to the channel surface and into a wavy layer close to the liquid-gas interface. In the continuous liquid layer region of the film, it is argued that the turbulence structure is similar to the structure of single phase turbulent pipe flow, and in the wavy layer region of the film, it is assumed that the eddy diffusion length is proportional to the thickness of this region. Experimental data in upflow and downflow confirmed the validity of the basic assumption of the turbulent structure in the film, and revealed the value for the wavy layer momentum diffusivity. This diffusivity is found to have a lower value than in the single phase pipe flow at the equivalent distances from the channel wall. The two-layer liquid film structure is integrated into an analysis for the prediction of hydrodynamics and heat transfer in annular two-phase flows. Analytic results are compared to the results of other analytical models and to the experimental data in upflow, downflow and horizontal flow. In all cases considered, very good comparison is achieved in both hydrodynamics and heat transfer.