Fire Banner

Wednesday, August 26, 2009

Visit by Dr Jomaas and seminar on Spherical Flames

Dr Grunde Jomaas, Lecturer in Fire Safety at Technical University of Denmark (DTU), is visiting the fire group and will give a seminar on Wed 2 Sept at 1pm in the Alexander Graham Bell Bldg. seminar room (3rd floor).

Dr Jomaas is a 2008 PhD graduate from Princeton University. In 2001, he got a BSc in Fire Protection Engineering from the University of Maryland (where he worked with Prof Jose Torero). After a year of research at Ecole Centrale Paris, he move to DTU Denmark in 2009. On top of his academic position, he is active in consultancy as a fire safety and combustion expert.

Seminar Abstract:
Experimental Observations of Propagation and Stability of Spherical Flames

High-fidelity experiments were conducted to define the transition boundaries of both cellular and spiral flame front instabilities, and also to determine cellular flame acceleration constants for outwardly propagating spherical flames in a dual-chamber design that allows near-constant experimental pressures up to 60 atmospheres. The flamefront movement was monitored using schlieren cinematography and recorded with a high-speed digital camera. The instant of transition to cellularity was experimentally determined for various fuels and fuel mixtures and subsequently interpreted on the basis of hydrodynamic and diffusional-thermal instabilities. Furthermore, exciting observations of spiral waves and target patterns over propagating flame surfaces in rich hydrogen-air, rich hydrogen-oxygen, and lean butane-oxygen-helium mixtures are shown to be well described by the Sivashinsky criterion for instability.

* See 2007 paper on Journal of Fluid Mechanics, "On transition to cellularity in expanding spherical flames".

No comments: