A tool for modelling spacer-filled MD channels based on open source CFD code

Abstract

The process of desalination by membrane distillation (MD) has attracted increased interest in recent years. To a large extent this is due to the fact that the driving force for this process is a relatively low temperature dierence between the feed and distillate sides of a hydrophobic porous membrane, which means that the process can easily be driven by solar thermal energy or waste heat. On the other hand, the relatively low temperature dierences involved also mean that the process is fairly sensitive to certain losses in the membrane channels, i.e. the drop in driving force associated with temperature polarisation. For this reason, it is important to study the detailed hydrodynamic and heat transfer conditions within the narrow ow passages of spiralwound or at MD modules in order to optimise their design. The present work reports on the development of a tool for 3D simulation of spacer-lled MD channels based on the open source CFD code library OpenFOAM. The paper discusses a number of modelling and implementation aspects including model geometry and computational domain, choice of boundary conditions, and discretisation schemes. Some initial results relating to the eect of spacer laments on the uid dynamics and heat transfer phenomena inside the channel are presented and briey discussed. A comparison of present results with results obtained using another CFD solver in a previous work [1] is also provided