Heat and mass transfer during contact drying of a sheet of moist material

Abstract

Observed are the processes of heat and mass transfer inside the layer (sheet) of wet material placed on flat heating surface of constant, but variable and controllable temperature, and exposed, from above, to the horizontal flow of air of variable and controllable velocity, temperature and humidity. The heat flow to the material in the observed contact drying process can be supplied conductively, convectively or simultaneously by use of both the mechanisms (from both sides of the sheet of wet material), whilst the water vapor is evaporated from the free upper surface of the sample into the stream of air flowing above it. The results of experimental evaluation of the process have been presented, analyzed and compared to the results acquired by numerical solving of sets of equations describing heat and mass transfer, boundary and initial conditions of the process..