Monday, 24 February 2014

The pyrolysis history of Perspex

We sent the image below, The pyrolysis history of Perspex, to the Fire Science Image competition at the 11th International Symposium on Fire Safety Science.

Photo by N. Roenner and G. Rein (Imperial College London) and R. Hadden (University of Edinburgh)
This composite shows the pyrolysis and burning of a sample (10 cm x 10 cm x 1.5 cm) of transparent Poly-methyl methacrylate (PMMA, Perspex) inside a Fire Propagation Apparatus (FPA).
The central image shows the diffusion flame established on top of the sample which is surrounded by the infrared lamps emitting a transient heat flux peaking at 30 kW after 300 s. The series to the right show the evolution of the PMMA sample during the fire. This was created by extracting samples at different times from identical experimental repeats.
PMMA is typically chosen for fire experiments because it is the polymer for which the flammability behaviour is best known. Despite this, the intricacy involved is patent. The melting, bubbling and pyrolysis mechanisms all contribute to create a dynamic image of the sample's history which illustrate the high complexity and beauty of fire phenomena. 
Licensed under a Creative Commons CC BY-NC-ND 3.0.

Computational Smouldering Combustion

I am delighted to announce that our work won the award for the Best Student Poster at the 11th International Symposium on Fire Safety Science, with the research on peat fires led by my PhD student X. Huang.

Fire Watch Constellation

I am delighted to announce that we won the award for the Best Fire Science Image at the 11th International Symposium on Fire Safety Science, with our entry titled Fire Watch Constellation (reproduced below).
Note: We have posted the image on the image repository of the European Geosciences Union

 Photo by E. Rackauskaite, X. Huang and G. Rein, Imperial College London. 
This composite shows a constellation of combined visual and infrared imaging of a smouldering combustion front spreading radially over a thin sample of dry peat. The central watch is created by a series of twelve wedges. Each edge is extracted from a photo taken every 5 min from an elevated view looking down into the sample during the one-hour lab experiment. The circular peat sample (D=22 cm) was ignited on the centre by an electrical heater. The average radial spread rate was 10 cm/h and the peak temperature 600˚C. The top figures show the virgin peat (left) and the final residue (right). The bottom figures show the wedges in visual (left) and infrared (right) imaging. Smouldering combustion is the driving phenomenon of wildfires in peatlands, like those causing haze episodes in Southeast Asia and Northeast Europe. These are the largest fires on Earth and an extensive source of greenhouse gases, but poorly studied. Our experiments help to understand this emerging research topic in climate-change mitigation by characterizing the dynamics of ignition, spread and extinction, and also measure the yield of carbon emissions. 

Licensed under a Creative Commons CC BY-NC-ND 3.0.