Computational Fluid Dynamics Modeling of Direct Contact Membrane Distillation for Low-Energy Desalination

Institut

Lehrstuhl für Thermodynamik (TUM-ED)

Typ

Masterarbeit /

Inhalt

 

Beschreibung

Background

Freshwater scarcity is increasing the need for energy-efficient desalination technologies. Membrane distillation (MD) is attractive because it can operate at moderate temperatures and low hydraulic pressure, and can potentially use low-grade or waste heat. Among MD configurations, direct contact membrane distillation (DCMD) is one of the simplest and lowest-cost module concepts: a hot saline feed stream and a cold distillate stream flow on opposite sides of a hydrophobic porous membrane. The temperature difference creates a vapor pressure gradient, water evaporates at the hot membrane interface, vapor passes through the membrane pores, and condensation occurs on the cold side. The behavior of the DCMD system can be investigated using Computational Fluid Dynamics (CFD) technique.

Objectives

(1) Implement or reproduce a 2D CFD DCMD simulation model for hot channel, membrane, and cold channel domains. Couple Navier-Stokes, energy, and species transport equations with a membrane vapor-flux model based on vapor pressure difference and diffusion through porous media.

(2) Validate the simulation against reported experimental or literature data for outlet temperatures and transmembrane water vapor flux.

(3) Study the influence of inlet feed temperature, inlet velocity, channel length, membrane properties, and flow configuration on desalination performance.

(4) Documentation and presentation of the project.

Methods

The project can be implemented in COMSOL Multiphysics, Ansys Fluent, OpenFOAM, or a Python-based finite-volume workflow:

(1) Build the DCMD geometry using literature dimensions for membrane length, channel height, module width, membrane thickness, porosity, tortuosity, and pore size.

(2) Solve laminar flow in the feed and distillate channels and compute temperature and concentration fields in the coupled domains. Represent membrane transport using Knudsen/molecular diffusion concepts and a vapor pressure driving force across the membrane.

(3) Perform a mesh-independence check and compare key observables with literature values.

(4) Run a parametric study for inlet temperature, inlet velocity, channel length, and selected membrane parameters.

Expected Outcomes

The student will gain hands-on experience in multiphysics CFD modeling of a real membrane desalination process. 

Voraussetzungen

• MSc student in mechanical engineering, chemical engineering, energy engineering, or a related field.

• Basic knowledge of fluid mechanics, heat transfer, mass transfer, or transport phenomena.

• Interest in numerical simulation. Experience with Ansys Fluent, or similar tools is helpful.

Möglicher Beginn

immediately

Kontakt

M.Sc. Kaiyan Jin
Raum: 5507.01.728
go59sormytum.de