Rheological and heat transfer characterizations of non-Newtonian fluid falling film in evaporation process

Abstract

A set of experimental equipment was established for falling film evaporation. The aqueous CMC (carboxymethylcellulo) solution was used to simulate the non-Newtonian fluid that obeys the power law model. Effects of rheology of the non-Newtonian fluid on heat transfer were investigated experimentally. A theoretical model was developed and coupling characteristics between rheology and heat transfer were described in non-Newtonian environmental fluid falling film in evaporation process. The different theoretical models were established for the developing region and the fully developed region in this evaporation process, respectively. Using finite difference method and shooting method, the simulated calculations were obtained. Furthermore, by introducing the generalized Reynolds number and the Prandtl number, which includes the necessary physical properties of the non-Newtonian fluid, a correlation about the Nusselt number was proposed for non-Newtonian fluid falling film in evaporation process.