3D CFD ANALYSIS OF EXHAUST FAN SYSTEM IN PAPER MILL FOR ENERGY SAVING

摘要

The purpose of this study is to conduct computational fluid dynamic (CFD) simulations for the paper mills in China. To prevent the accumulation of water vapor for causing condensation on the interior surfaces of the building’s rooftop, this research explored a solution to implement exhaust fans for capturing and exhausting vapor to outdoor environments. The simulation results were based the ventilation system design configuration and the measurements of vapor mass flow rates around the paper machine. The mass conservation check indicated that the differences between the inflow mass flow rate and exhausted mass flow rate were less than 1.2% for each case. The percentages of water vapor expelled by exhaust fans were 81.1%, respectively, in summer. The water vapor concentration distribution showed that the vapor pressure over the ceiling surface was higher than the corresponding saturated vapor pressure at the same temperature, causing the condensing phenomenon. Based on the covering region of condensed water vapor, the predictions also indicated that turning off 18 exhaust fans can not only prevent the occurrence of vapor condensation but also effectively save up to 25% of energy consumption.