Heat and Mass Transfer in Matrices of Hygroscopic Wheels

Abstract

In the present chapter the sorption and the mass diffusion phenomena in the porous desiccant layer are described aiming a detailed numerical modelling of hygroscopic wheels. A particular desiccant medium (silica gel Regular Density) is characterized as well as a representative cell of the corrugated matrix. The heat and mass transfers in the gas domain of the matrix channels are analysed addressing also the validity of the so-called low mass transfer rate theory. The mass transfer convective coefficient is evaluated through the use of the Chilton-Colburn analogy. The detailed numerical model proposed for the simulation of the behaviour of a representative channel of the matrix is briefly described. Results of the cyclic behaviour of an element of the channel wall are presented and a parametric study is performed concerning the influence of the rotation speed and of the thickness of the desiccant layer on the behaviour of hygroscopic wheels.KeywordsNusselt NumberAdsorbed WaterHeat Transfer RateWater Vapour ContentKnudsen DiffusionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.