Mechanical Engineering MS Thesis Defense by Mr. Aleks Bourgoun
When: Tuesday,
August 17, 2021
1:30 PM
-
3:30 PM
Where: > See description for location
Description: Mechanical Engineering MS Thesis Defense by Mr. Aleks Bourgoun
DATE:
August 17, 2021
TIME:
1:30 p.m. -3:30 p.m.
LOCATION:
ZOOM: https://umassd.zoom.us/j/94371085657?pwd=Y3dVMkU1cXVreFBIcjRVenVZTUpIZz09
Meeting ID:943 7108 5657
Passcode:291208
TOPIC:
A Numerical and Experimental Study of Gas Diffusion from Super-Hydrophobic Surfaces to Under-Saturated Liquid
ABSTRACT:
The micro/nano-textured Super-Hydrophobic Surface (SHS) can trap a layer of gas bubbles when submerged in liquid, and consequently provides various benefits, such as self-cleaning, anti-corrosion, anti-icing, anti-biofouling, and drag reduction. However, the entrapped gas bubbles can be slowly dissolved into the ambient liquid when the liquid is under-saturated, causing a loss of all the benefits from the SHS. In this work, we study this gas diffusion process for an SHS fully submerged in under-saturated liquid through a combination of computational and experimental approaches. First, we solve the dissolved gas concentration in the liquid by COMSOL Multiphysics simulations. We present the time evolutions of gas concentration profile, mass flux, diffusion length, and amount of gas remaining on the surface. We find that the results agree very well with a simple one-dimensional diffusion model. We also examine the impact of SHS texture (e.g., fraction of surface area covered by gas, texture sizes) and domain size on the rate of mass flux and the lifetime of the gas on a SHS. Second, we experimentally measure the rate of gas transfer from an SHS to liquid by bright-field microscopy, planar laser induced fluorescence, and reflection interference contrast microscopy. We discuss the experimental setups, SHS fabrication methods, and data analysis procedures. Unlike numerical simulations, the experiment results show a non-uniform gas flux across the surface, probably due to the initial disturbance by the filling of water into the experimental chamber. Overall, our research provides guidelines on designing long lifetime SHSs for various underwater engineering applications.
ADVISOR:
Dr. Hangjian Ling, Assistant Professor Department of Mechanical Engineering, UMass Dartmouth
COMMITTEE MEMBERS:
-Dr. Sankha Bhowmick, Professor of Mechanical Engineering, UMass Dartmouth
-Dr. Mehdi Raessi, Associate Professor of Mechanical Engineering, UMass Dartmouth
Open to the public. All MNE students are encouraged to attend.
For more information, please contact Dr. Hangjian Ling (hling1@umassd.edu, 508-999-8540).
Thank you,
Sue Cunha
scunha@umassd.edu
DATE:
August 17, 2021
TIME:
1:30 p.m. -3:30 p.m.
LOCATION:
ZOOM: https://umassd.zoom.us/j/94371085657?pwd=Y3dVMkU1cXVreFBIcjRVenVZTUpIZz09
Meeting ID:943 7108 5657
Passcode:291208
TOPIC:
A Numerical and Experimental Study of Gas Diffusion from Super-Hydrophobic Surfaces to Under-Saturated Liquid
ABSTRACT:
The micro/nano-textured Super-Hydrophobic Surface (SHS) can trap a layer of gas bubbles when submerged in liquid, and consequently provides various benefits, such as self-cleaning, anti-corrosion, anti-icing, anti-biofouling, and drag reduction. However, the entrapped gas bubbles can be slowly dissolved into the ambient liquid when the liquid is under-saturated, causing a loss of all the benefits from the SHS. In this work, we study this gas diffusion process for an SHS fully submerged in under-saturated liquid through a combination of computational and experimental approaches. First, we solve the dissolved gas concentration in the liquid by COMSOL Multiphysics simulations. We present the time evolutions of gas concentration profile, mass flux, diffusion length, and amount of gas remaining on the surface. We find that the results agree very well with a simple one-dimensional diffusion model. We also examine the impact of SHS texture (e.g., fraction of surface area covered by gas, texture sizes) and domain size on the rate of mass flux and the lifetime of the gas on a SHS. Second, we experimentally measure the rate of gas transfer from an SHS to liquid by bright-field microscopy, planar laser induced fluorescence, and reflection interference contrast microscopy. We discuss the experimental setups, SHS fabrication methods, and data analysis procedures. Unlike numerical simulations, the experiment results show a non-uniform gas flux across the surface, probably due to the initial disturbance by the filling of water into the experimental chamber. Overall, our research provides guidelines on designing long lifetime SHSs for various underwater engineering applications.
ADVISOR:
Dr. Hangjian Ling, Assistant Professor Department of Mechanical Engineering, UMass Dartmouth
COMMITTEE MEMBERS:
-Dr. Sankha Bhowmick, Professor of Mechanical Engineering, UMass Dartmouth
-Dr. Mehdi Raessi, Associate Professor of Mechanical Engineering, UMass Dartmouth
Open to the public. All MNE students are encouraged to attend.
For more information, please contact Dr. Hangjian Ling (hling1@umassd.edu, 508-999-8540).
Thank you,
Sue Cunha
scunha@umassd.edu
Topical Areas: Faculty, General Public, Staff and Administrators, Students, Students, Graduate, Students, Undergraduate, University Community, College of Engineering, Mechanical Engineering, Lectures and Seminars