Department
Mechanical and Aerospace Engineering
Major
Mechanical Engineering
Research Advisor
Liang, Zhi
Advisor's Department
Mechanical and Aerospace Engineering
Funding Source
National Science Foundation (NSF) Grant No. 2310833
Abstract
The evaporation or condensation rate of a liquid surface is directly proportional to the mass accommodation coefficient (MAC). Since the MAC is difficult, if not impossible, to experimentally measure, molecular dynamics (MD) simulations have been employed to study it. Experimental studies have shown that airborne hydrocarbon contaminants from a variety of sources can adsorb on liquid surfaces and significantly alter the surface properties. We have therefore studied the effects of organic surface contaminants, which are immiscible with water, on the MAC using equilibrium and nonequilibrium MD simulations. Our equilibrium MD simulation results show that the MAC decreases linearly with increases in surface coverage by contaminants while the nonequilibrium MD simulations show that the Schrage equation, which has been proven to be accurate in predicting the evaporation and condensation rates of clean liquid surfaces, is also accurate in predicting the evaporation and condensation rates of contaminated water surfaces. We have also validated the key assumption about the molecular velocity distribution in the Schrage analysis for vapor molecules near the water surfaces. When the water surface is almost completely covered by contaminants, we find that the adsorption flux of vapor molecules dominates over evaporation or condensation flux and leads to a false prediction of the MAC from the Schrage equation.
Biography
Jordan Hartfield is a senior mechanical engineering student who has been working with Dr. Zhi Liang on the research of water evaporation and condensation rates for nearly a year. He spent the summer of 2023, funded by the Future Research Pioneers Program (FRPP) and the Opportunities for Undergraduate Research Experiences (OURE), working on the effects of organic surface contaminants on water surfaces and has since been deepening his understanding of the underlying principles of molecular dynamic simulations. Jordan plans to start his Ph.D. of mechanical engineering in the fall of 2024 with a focus on thermal fluid sciences. He hopes to use MD simulations for conducting more research on the effects of surface contaminants in evaporation and condensation processes so that he might be able to better model these processes and their applications.
Research Category
Engineering
Presentation Type
Poster Presentation
Document Type
Poster
Location
Innovation Forum - 1st Floor Innovation Lab
Presentation Date
10 April 2024, 1:00 pm - 4:00 pm
Organic Contaminant Effects on the MAC of Water
Innovation Forum - 1st Floor Innovation Lab
The evaporation or condensation rate of a liquid surface is directly proportional to the mass accommodation coefficient (MAC). Since the MAC is difficult, if not impossible, to experimentally measure, molecular dynamics (MD) simulations have been employed to study it. Experimental studies have shown that airborne hydrocarbon contaminants from a variety of sources can adsorb on liquid surfaces and significantly alter the surface properties. We have therefore studied the effects of organic surface contaminants, which are immiscible with water, on the MAC using equilibrium and nonequilibrium MD simulations. Our equilibrium MD simulation results show that the MAC decreases linearly with increases in surface coverage by contaminants while the nonequilibrium MD simulations show that the Schrage equation, which has been proven to be accurate in predicting the evaporation and condensation rates of clean liquid surfaces, is also accurate in predicting the evaporation and condensation rates of contaminated water surfaces. We have also validated the key assumption about the molecular velocity distribution in the Schrage analysis for vapor molecules near the water surfaces. When the water surface is almost completely covered by contaminants, we find that the adsorption flux of vapor molecules dominates over evaporation or condensation flux and leads to a false prediction of the MAC from the Schrage equation.
