Simulation investigation of the effect of heating temperature and porosity of porous media on the water evaporation process

Abstract

Abstract In the study, carbon fiber as porous media, water and vapor as liquid and gas phases, respectively, the evaporation process of multiphase fluid in carbon fiber was explored based on the pore network model. The Micro-CT technology was adopted to reconstruct the structure of carbon fiber. The applicability of the CFD model adopted in the simulation was validated by experiment. Effect of heating temperature and porosity on the evaporation process was investigated in detail. The study found that at various heating temperatures, fluid temperature increases gradually with time, and tends to be constant when it reaches a certain temperature. When heating temperature is high, the constant temperature is large, the time to arrive the constant temperature is short. The liquid evaporation rate V e and the heat absorbed by the fluid every 0.5 s Q 0.5 increase first, and decrease gradually when a maximum value is reached. When the heating temperature is high, the maximum that V e and Q 0.5 can be obtained is also large, the required time is also short. In porous media with different porosity, fluid temperature rises to an approximate constant. V e and Q 0.5 increase first, and decrease gradually after reaching a certain maximum value. The maximum values of V e and Q 0.5 in porous media with porosity of 0.598 are the largest.