The collaborative study was produced by Professor Dame Ann Dowling and Dr Nedunchezhian Swaminathan (both of the Department of Engineering), along with Dr Rama Balachandran (University College London) and Gang Xu (Chinese Academy of Science).The detail of the study is published in the Journal of Fluid Mechanics article "Heat release rate correlation and combustion noise in premixed flames, vol. 681, pp. 80-115, 2011"

Dr Swaminathan explained: "Since the 1950s many attempts have been made to unravel the science behind combustion noise. These studies identified that the space-time correlation of the rate of fluctuating heat relate rate per unit volume is the central quantity and the overall sound pressure level (OASPL) depends only on the spatial correlation.

"The heat release rate which is directly linked to the fuel consumption rate is strongly influenced by temperature and turbulence in non-linear fashion and so the analysis of this correlation has been a very difficult task.

"The analysis framework developed at the Department of Engineering, using data from high fidelity numerical simulations and laser diagnostics of lean combustion, has helped to calculate and model the spatial correlation accurately. The OASPL computed using this model in a truly predictive approach compared very well with the measured values. The model resulted from this work will help us to calculate the gas turbine engine noise with an increased level of confidence."

Fuel-lean burning is the potential way forward to reduce pollutant emissions from engines used for air and surface transport. However, this mode of burning is known to be unstable involving highly unsteady flames emitting sound waves. The noise coming from these waves is emerging as an important source of noise in lean-burn systems in general and specifically for gas turbine engines partly because other noise sources in these engines have been reduced. Thus, the engine noise coming from combustion sources can become an important differentiator for gas turbine manufacturers with potential economic implications. Hence, a thorough understanding of these noise sources and their behaviours at a fundamental level is a necessary requirement to devise strategies to mitigate this noise from lean-burn systems.

The Sugden Award is an annual award for contributions to combustion research. The prize is awarded by the British Section of The Combustion Institute for the published paper with at least one British Section member as author and is named after Sir Morris Sugden.The aims of the award are threefold: a) to recognise good work in combustion, b) to encourage membership of the Combustion Institute and c) to encourage combustion research and publication, especially by British institutions.