主講人：曾亞婷 助理教授

演講者現職：Dept. Mechanical and Aerospace Engineering Case Western Reverse University

日期：107年10月18日(星期四)

時間：下午14：30~16：00

地點：工學院演講廳(工EN2028)

演講題目：Microgravity Experiments of Concurrent Flame Spread over Thin Solid Fuels

演講摘要：Flame spread and extinction over solid fuels are two of the most important characteristics of material flammability. Understanding these two processes can help us assess fire hazards and suppress fires. In the last few decades, numerous flame spread and extinction experiments have been carried out in normal (earth) gravity. In normal gravity, buoyancy has a major influence on fire growth processes and may mask observation of the fundamental underlying physics. In addition, it is commonly acknowledged that buoyancy-induced flow renders flame spread to be an accelerating process - both the rate of fire spread and flame length continually increase. Soot radiation, which increases with fire size, further complicates the problem.
In a microgravity environment, buoyancy is essentially eliminated and forced flow can be imposed on the sample independent of other parameters. Rather than being classified as upward (or in a particular direction), flame spread in microgravity is defined as concurrent-flow or opposed-flow depending on its direction relative to the flow.
This presentation introduces various experiments examining concurrent flame spread processes in microgravity environments, including tests done using NASA’s Zero Gravity Facility (the 5s-drop tower), unmanned space vehicles, and aboard the International Space Station. Flame spread over large and small samples, with different sample thicknesses, with different flow speeds, and with different confinement will be presented. Results from normal gravity experiments and numerical simulations will also be presented to complement some of the microgravity results.

Dr. Ya-Ting T. Liao, an assistant professor at Case Western Reserve University, leads the Computation Fire Dynamics Laboratory in the Department of Mechanical and Aerospace Engineering. Dr. Liao’s research projects range from basic fire science (material flammability, solid pyrolysis, ignition, microgravity combustion, flame spread, etc.) to understanding fire behavior in specific situations (such as structures, spacecraft, or wildland fires). Through these projects, her lab improves the accuracy and realism of the chemistry and physics underlying computational models of combustion and fire. They design and perform experiments that provide data to clarify, prove, or suggest model parameters. They also use computational models to predict fire behavior, to characterize safety risks, and to develop safer structures. Dr. Liao’s work has been supported by NSF, NASA, CASIS, and UL. She currently serves on the Board of Advisors in the Central State Section of the Combustion Institute.
Prior to joining the faculty at Case, Dr. Liao has had experiences in industry. From 2013-2014, she worked on thermal fluids and two-phase flow problems in the petroleum industry as a consultant and as a thermo-fluids specialist at FMC Technologies. In 2011-2012, Dr. Liao worked at Bloomberg LP as a software developer.
Dr. Liao obtained her PhD in Mechanical and Aerospace Engineering from Case Western Reserve University in 2011. She double-majored in Mechanical Engineering and Physics in National Taiwan University in 2004.