ANALYSIS OF TWO-PHASE FLOW IN DOUBLE-PIPE CONDENSERS AND EVAPORATORS WITH SPECIAL EMPHASIS ON TRANSITION ZONES: NUMERICAL MODEL AND EXPERIMENTAL COMPARISON

摘要

A numerical study of the thermal and fluid-dynamic behavior of the two-phase flow in conducts is presented. The numerical simulation has been developed by means of the finite volume technique based on a one-dimensional transient integration of the conservative equations. The discretized governing equations are solved using the step by step algorithm or the pressure-based method SIMPLEC, giving special emphasis on the treatment of the transition zones between the different phases. The numerical comparative results show the verification of the numerical model developed, while the experimental comparative results validate the simulation and show the improvements in the solution when the special treatment is used. A experimental unit has been designed and built to analyse single stage vapour compression refrigerating equipment and to compare the whole refrigerating system numerically. A detailed instrumented evaporator has been added in order to obtain the experimental information of temperature and pressure distribution along the heated duct. The electrically heated instrumented evaporator has given detailed experimental data to be compared with the numerical results.