STUDY ON THE FALLING FILM ABSORPTION OUTSIDE SMOOTH AND ENHANCED TUBES*

ABSTRACT: In this paper, mathematical models of smooth and enhanced tubes were established. A new mathematical model in evaluating single-tube falling film absorption effect outside enhanced tubes is proposed. The liquid film outside enhanced tubes is assumed to consist of two layers, i.e. internal and external layers. The analytical solutions to the distribution of the velocity, temperature and concentration in the internal layer are obtained by means of theoretical analysis, while the solutions in the external layer are calculated by using numerical method. The governing equations of the two layers are coupled using a second-order coupling method. The effects of the height and the angle of the ribs on the performances of the heat and mass transfer of the liquid film are discussed. It is shown that the agreement is good between the calculation results and the experimental data. [Copyright &y& Elsevier]