FRICTION, HEAT AND MASS-TRANSFER FOR PAPER DRYING

The process of paper drying has been investigated on an experimental b asis. The mass transfer coefficient through rough, permeable paper dry ing fabrics has been shown to be considerably reduced below that from an open surface by between 60-75%, whilst the composition of the paper sheet and increases in felt tension were found to have a minor effect on the observed drying rates (<10%). The turbulence data for the smoo th curved hill arrangement supported the prevailing literature in term s of both skin friction coefficient and velocity profiles. The finding s of this study have been applied in a mathematical model, relating ke y operating conditions to achievable drying rates, and highlight the o pportunity for the reduction of energy consumption in paper drying. (C ) 1998 Elsevier Science Ltd.