Measuring Laminar Burning Velocities

Laminar Burning Velocity Measurements Over Wide-Ranging Temperatures and Pressures for Renewable and Conventional Fuels - funded by EPSRC (EP/H031197/1) and Shell Global Solutions.

Overview

Cellularity developing on the surface of a spherically expanding flameA spherical combustion bomb vessel is being used to measure laminar burning velocities for a range of liquid and gaseous fuels at a wide range of initial temperatures and pressures created by an environmental chamber surrounding the vessel. Burning velocities can be calculated from both pressure measurements (using a multi-zone model) and schlieren photography of the flame front using a recently acquired high speed digital camera and the windows in the bomb. This also allows image analysis of cellular flames.

The project also includes testing of mixtures of fuels in order to revise mixing rules with the effects of stretch and cellularity taken into account. Furthermore, experiments with real residuals will be performed to simulate EGR in a gasoline spark ignition engine. Real residuals offer advantages over articifical residuals created by mixtures of inert gases.

For further details of the BOMB program, Oxford's multi-zone combustion model, please see the poster below or refer to Saeed and Stone (2004) Comb. Theory & Model. 8, pp 721-743.

Bomb schematic. Diameter 160 mm

Papers

Marshall, S.P., Stone, R., Heghes, C., Davies, T.J. and Cracknell, R.F. (2010), "High Pressure Laminar Burning Velocity Measurements and Modelling of Methane and n-Butane", Combustion Theory and Modelling 14(4) pp519-540

Posters

S.P. Marshall, C.R. Stone, R. Cracknell, T. Davies and C. Heghes (2009), "Developing the Fuels of the Future", SET for Britain Poster Competition, House of Commons, London, March 2009, E33

S.P. Marshall, C.R. Stone, R. Cracknell and C. Heghes (2008), "Laminar Burning Velocity Measurements in a Constant Volume Vessel", 32nd International Symposium on Combustion, Montréal, August 2008, W4P194

Presentation

S.P. Marshall, C.R. Stone, R. Cracknell and C. Heghes (2008), "High Pressure Laminar Burning Velocity Measurements", 6th International Seminar on Flame Structure, Brussels, September 2008, OP-14

Timescale

Start : 1st October 2006. End : 31st March 2010

Involved Parties

Group : S.P. Marshall, C.R. Stone
Project Support : Shell Global Solutions

Videos

A spherical isooctane flame visualised by a schlieren photography system and Photron FastCam 1024 PCI high speed camera at 3,000 fps. As the flame expands its surface becomes unstable and cracks. Cross-cracks then form cells on the surface. Front and back surfaces of the sphere can be distinguished by light and dark lines.

This video is available in AVI and WMV formats, as well as low quality embedded Flash.