Complete condensation of forced convection two-phase flow in a miniature tube

A physical and mathematical model of annular film condensation in a miniatu re tube has been developed. In the model the liquid flow has been coupled w ith the vapor flow along the liquid-vapor interface through the interfacial temperature, heat flux, shear stress, and pressure jump conditions due to surface tension effects. The model predicts the shape of the liquid-vapor i nterface along the condenser and the length of the two-phase flow region. T he numerical results show that complete condensation of the incoming vapor is possible at comparatively low heat loads. Observations from a flow visua lization experiment of water vapor condensing in a horizontal glass tube co nfirm the existence and qualitative features of annular film condensation l eading to the complete condensation phenomenon in small diameter (d <3.5 mm ) circular tubes.