Heat transfer characteristics in horizontal rectangular channel of multi-channel cylinder dryer

The multi-channel cylinder dryer (MCD) for drying paper may be a promising solution to the energy consumption in paper drying. However, energy consumption is related to the heat transfer characteristics of the steam condensation process. The investigation of heat transfer coefficient (HTC) in horizontal rectangular channel of MCD was experimentally performed in this paper. And the changes of overall HTC, condensation HTC and HTC of cooling water side were explored under different condensing conditions. The results showed that the overall HTC increased with the increasing of the Nusselt number of cooling water, Reynolds number of cooling water and mass flow rate of cooling water. And the condensation HTC will increase with the increasing mass flow rate of cooling water and Reynolds number of cooling water, however, there is a fluctuation of the condensation HTC changing with Reynolds number of cooling water increasing. A better heat transfer performance can be achieved by the increase of steam mass flux, while excessive pressure drop can be avoided by setting a reasonable steam mass flux, 24 kg · m-2· s-1 © 2020 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.