[CCoE Notice] Master’s Thesis Defense Announcement

[Khator, Suresh]

master’s Thesis Defense: Aritra Sur

 

Committee Members: Dr. Dong Liu, Dr. Keith Hollingsworth (Mechanical Engineering),  Dr. Manolis Doxastakis (Chemical Engineering)

 

Date and Time: 4th Aug, 2010, 2.00 pm - 4.00 pm,  Location: ME Large Conference Room

 

 

Abstract

In this work, adiabatic water-air two-phase flows were studied experimentally in circular microchannels with inner diameters of 100, 180 and 324 μm. High-speed photographic technique was employed to visualize the two-phase flow patterns over a wide range of liquid and gas superficial velocities. Two-phase flow maps were constructed and the transition boundaries between different flow regimes were identified. In addition, the two-phase pressure drop was measured and compared with the models available in the literature. 

To further explore the fundamental mechanisms governing the two-phase flow pattern formation, a cross-junction microfluidic chip with a rectangular cross section of 300 μm × 100 μm was used to explore the dynamics of bubbly, slug and annular flows. Numerical models using the volume-of-fluid (VOF) approach were developed to simulate the two-phase mixing and flow pattern development in the microfluidic chip. The roles of the inertia, viscous shear and surface tension forces in two-phase flows were evaluated. 

Finally, the effects of surfactant on the two-phase flow pattern and pressure drop in microchannels were studied with the motivation that addition of surfactant will help to eliminate intermittent two-phase flow patterns and alleviate flow instability. Air-water mixtures with trace quantities of sodium dodecyl sulfate (SDS) were used in the experiments. The results were compared to the data obtained from water-air flow without surfactants. It was found that addition of surfactants brings in significant modification to the two-phase flow regimes and their transition characteristics in microchannels, in particular, the most intermittent slug flow is effectively suppressed however,  the two-phase pressure drop is reduced.

 

_______________________________________________________

Suresh K. Khator, Ph.D., P.E.                         Phone: 713-743-4205         

Associate Dean, College of Engineering    Fax: 713-743-4214

University of Houston                                     Email: skhator at uh.edu   

E421 Engineering Bldg 2                                www.egr.uh.edu/ie

Houston, TX 77204-4008

 

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