Evaluation of the convection moisture coefficient using various methods

Abstract

When we solute the issue of moisture transfer it is necessary to deal with two mechanisms: molecular mass transfer and the convective mass transfer. The driving force of transmission is the difference of the concentrations of moisture, respectively the difference of the partial vapor pressures. For the convective mass transfer is the key value the convective moister coefficient, which depends on many parameters, but for one particular experimental design will be influenced mainly by velocity. Experimentally detectable is the total moisture transfer caused by both mechanisms, it is the overall moisture transfer coefficient. In previous work we tried from a set of measured data during various modes and for different samples evaluate the dependence of the convection moister coefficient on the flow velocity for the concrete arrangement of the experiment. The aim of this study is to compare these values of the convection moister coefficient with the values calculated from criterial equations using the analogy of heat and mass transfer.