Modeling of Oxygen Mass Transfer Coefficients in an Eulerian-Eulerian Framework
Restricted (Penn State Only)
- Author:
- Erdman, Matt D
- Graduate Program:
- Mechanical Engineering (PHD)
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- August 09, 2023
- Committee Members:
- Alexander Rattner, Major Field Member
Michael Krane, Outside Unit & Field Member
Robert Kunz, Professor in Charge/Director of Graduate Studies
John Cimbala, Chair, Minor Member & Dissertation Advisor
Fan-Bill Cheung, Major Field Member - Keywords:
- CFD
Bubble Column
kla
Volumetric Mass Transfer Coefficient
Short Bubble Column - Abstract:
- This study investigates current volumetric mass transfer coefficient models in short bubble columns. As population levels rise, water treatment in the form of aeration is of increasing importance in today’s world. This study is motivated to improve dissolved oxygen mass transfer modeling to enhance the capability of aeration techniques. Current literature suggests a wide range of both liquid film mass transfer coefficients and volumetric mass transfer coefficients, but the current models produce a wide range of values when applied to the same flow conditions. Although global volumetric mass transfer coefficients have been shown to be non-physical, as their values can vary throughout a bubble column, they are still the dominating coefficients used in bubble column mass transfer due to the difficulty in experimentally measuring local volumetric mass transfer coefficients. Therefore, volumetric mass transfer correlations that account for the varying local values are of utmost importance. Nonetheless, most literature neglects the influence of bubble column height on the volumetric mass transfer coefficient. Those studies that do account for height still neglect sparger geometry in their formulations. However, this study uses CFD to demonstrate that both initial bubble diameter and overall sparger diameter (compared to column diameter) have significant impact on the volumetric mass transfer coefficient for short bubble columns operating in the homogeneous bubble regime. Furthermore, this study proposes a new CFD-generated correlation for volumetric mass transfer coefficient that incorporates initial bubble diameter, inlet geometry ratios, gas superficial velocity, and height. Furthermore, this study finds that for short bubble column operating in the homogenous bubble regime, the volumetric mass transfer coefficient varies with column height via a power of -0.140, with the inlet sparger diameter ratio via a power of 0.997, with the initial bubble diameter of via a power of -1.12, and with the gas superficial velocity via a power of 0.675.