Three-dimensional heat transfer coefficient distributions in a large horizontal-tube falling film evaporator

The distributions of the heat transfer coefficient in a large horizontal-tube falling film evaporator under different operating conditions were investigated with numerical simulation in this paper based on the distributed parameter model (DPM). The heat transfer coefficient distributions along the tube row direction, tube length direction, and tube column direction were analyzed with the brine inlet spray density ranging from 0.05 kg/m s to 0.09 kg/m s and the brine inlet salinity from 30 g/kg to 50 g/kg. Results show that the heat transfer coefficient has higher values for the evaporating zone than the preheating zone. With the operating conditions included in this paper, the change of brine inlet salinity leads to a wider variation range of heat transfer coefficient along the tube length direction for the evaporating zone than the change of brine inlet spray density. The change of brine inlet spray density leads to a wider variation range of heat transfer coefficient along the tube row direction for the first tube pass and along the tube length direction for the preheating zone than the change of brine inlet salinity. (C) 2014 Elsevier B.V. All rights reserved.