各位老师：

　 美国伍斯特理工（WPI）Ali S. Rangwala博士将于本月18-19日访问实验室并做学术报告，请感兴趣老师积极参加，并请通知各组同学积极参加。

报告人：Ali S. Rangwala 
报告时间：12月18日（星期四）15:00-16:00 
报告地点：特种实验楼二楼学术报告厅 
报告人单位： 
Department of Fire Protection Engineering, 
Worcester Polytechnic Institute, Worcester, MA 01609 USA

报告题目：Flame Propagation in Dust Clouds

报告摘要：

Dust deflagrations or flame propagation in a mixture of flammable
particles (~10 - 100 μm) and air or gases has gained increasing
importance in industrial fire and explosion safety. Every year dust
deflagrations in coal mines and chemical plants cause extensive material
damage, injury, and loss of life. Current guidance for prevention and
suppression originates from experiments performed in simple vessel
arrangements, and the parameters used to assess the hazard of flammable
dusts are empirically driven. The problem is thus unresolved from a fire
and explosion safety perspective. From a scientific viewpoint enhancing
our fundamental knowledge of particle combustion lies at the heart of
national security priorities such as energy efficiency and pollution
control by improving the design of power plants. There has also been a
recent push towards studying influence of nano-particulate matter in
combustion systems.

In this talk, I will describe the results of laboratory experiments to
identify the controlling parameters of laminar and turbulent hybrid dust
deflagration mechanisms (Xie et al., Comb. Flame, 159, 2449-2456, 2012,
and Rockwell and Rangwala, Comb. Flame, 160, 635-640, 2013). A novel
premixed-dust-air burner is designed to measure the burning velocity of
a hybrid mixture of Pittsburgh seam coal dust, with typical particle
sizes in the range of 25 to 106 μm and methane-air. Figure 1 depicts
shadowgraph images of a sample of flames tested. The results show that
adding coal dust in methane-air premixed flame reduces the burning
velocity for laminar flames and increases as turbulent intensities are
increased. Two competing effects are considered to explain these trends.
The first effect is due to volatile release, which increases the overall
equivalence ratio and thus, the burning velocity. The second is the heat
sink effect the coal particles take up to release the volatiles. A
mathematical model is developed considering these effects.

报告人简介：

Ali S. Rangwala is an associate professor in the department of Fire
Protection Engineering at Worcester Polytechnic Institute (WPI). He has
a BS in Electrical Engineering, from the Government College of
Engineering, Pune, India (2000), an MS in Fire Protection Engineering
from the University of Maryland, College Park (2002), and a PhD in
Mechanical and Aerospace Engineering from the University of California,
San Diego (2006). Professor Rangwala’s research interests are in the
area of industrial fire and explosions. His recent projects include,
deflagration of combustible dust clouds, ignition behavior of
combustible dust layers, in-situ burning of oil, spread of an oil slick
in channels, velocity measuring techniques in fire induced flows, and
flame propagation and burning rate behavior of condensed fuel surfaces.

火灾科学国家重点实验室
2014.12.16