HYDRODYNAMICS OF TWO-PHASE LOOP THERMOSYPHON

Abstract

Two-phase loop thermosyphons are important devices for large heat transport to a longer distance. The hydrodynamics of such device is closely related with the evaporator and condenser details. The evaporator is modeled by an integral balance of bubble flow, considering the relative velocity difference between the vapor and liquid. The condenser is calculated by liquid film condensation of vapor-liquid concurrent flow, corresponding to the two shear forces of viscous flow and momentum transfer. For the evaporator of one two-phase loop thermosyphon, the vapor bubble and liquid flow velocities, the axial density of the vapor-liquid mixture are formulated and analyzed. For the whole loop, the equivalent liquid position of operating evaporator, the driving liquid position difference between that in the liquid line and that of the evaporator equivalent, the liquid position difference in the liquid line before and after operating, are calculated and analyzed. The evaporator model and results can be referenced to the optimal design.