Date

2015

Document Type

Thesis

Degree

Master of Science

Department

Mechanical Engineering

First Adviser

Oztekin, Alparslan

Other advisers/committee members

Harlow, Gray

Abstract

Computational fluid dynamics simulations are conducted for multicomponent fluid flows over banks of hollow fiber membranes. The hollow fiber membrane systems is considered here for gas separation applications. Separation of carbon dioxide (CO2) from methane (CH4) is studied using hollow fiber membranes packed in different arrangements. The membrane surface is considered as a functional surface where the mass flux and concentration of each species are coupled and are determined as a function of the local partial pressures, the permeability, and the selectivity of the membrane. k-ω Shear Stress Transport (k-ω SST) turbulent model is employed to study the mixture flow over banks of hollow fiber membrane for values of the Reynolds number up to 1000. The flow structure around the hollow fiber membranes dominates the performance of the separation process. This study demonstrates clearly that good mixing in the bank of hollow fiber membranes enhances the separation performance. The results show that hollow fiber membrane module with staggered arrangement performs much better than that with inline arrangement. For the spiral wound membrane, it has been shown that membrane performance could be greatly enhanced by momentum mixing in the feed channel induced by spacers. Square shaped spacer will be considered in the inline arrangement for values of the Reynolds number up to 500. In order to validate the turbulence model transient flow simulations are conducted using lattice Boltzmann method. The lattice Boltzmann method to simulate flow in the geometries related to the spiral wound membrane modules is developed by our research group at Lehigh. Two dimensional nine velocity directional, D2Q9, lattice arrangement with multi-relaxation time (MRT) lattice Boltzmann method is used to simulate transient flow field while single relaxation time (SRT) lattice Boltzmann method. Simulations are performed to determine concentration field for values of Re up to 300. The bounding surfaces are treated as impermeable walls for simulations conducted using the lattice Boltzmann method. The results predicted by the lattice Boltzmann method and the SST turbulence model agree well, validating the turbulence model and the numerical method.

Share

COinS