Numerical and experimental investigation on the heat and mass transfer of falling film and droplet regimes in horizontal tubes LiBr-H2O absorber

摘要

A numerical model concerning heat and mass transfer of falling film and droplet regimes in horizonal tubes absorber is presented in this paper. By visualization experiments, actual flow patterns of falling film process are investigated when the tube space is 16 mm. The visualization results indicate that the droplet regime between tubes can be divided into three regimes, namely pendant droplet regime, liquid column regime and falling droplet regime. Through MATLAB image analysis, the prediction curves of droplet surface area with time and droplet volume with time are obtained, which can be applied to the numerical model of falling film heat and mass transfer. The accuracy and reliability of the numerical simulation results are verified by experimental data. In the three regimes of droplet between tubes, the pendant droplet regime is considered to be in dominate. In addition, the effect of solution flow rate on vapor absorption is discussed in detail. The simulation results demonstrate that the vapor absorption of the droplet between tubes cannot be ignored. With the increase of the solution flow rate, the vapor absorption rate of droplet regime between tubes can reach about 50%.