New data on combustor cooling in lean-burn engines Employing a higher air-to-fuel ratio, lean-burn engines result in considerably improved fuel economy and fewer greenhouse gases. High-resolution data provided by EU-funded scientists enabled disclosing the interaction of cooling jets with the strong air-fuel swirl created in the combustion chamber of such engines. Industrial Technologies Energy Fundamental Research © Eunika Sopotnicka, Shuttertsock Modern gas turbine combustors use combustor tiles to protect walls from hot gases. However, in newer engines that operate on a thinner mixture of fuel, higher pressures and temperatures are present. In this case, the amount of air used for cooling walls needs to be reduced to allow the maximum amount of air to flow though the fuel injector. This can be achieved by combining effusion cooling on the hot side with cooling impingement on the cold side of the tiles. The EU-funded project NEWSMILE (Near-wall simulations and measurements in lean-burn engines) provided measurement data that improves the accuracy of current models regarding wall temperatures and thermal stresses. Its aim was to experimentally investigate the interaction of film cooling and swirling flames using advanced laser diagnostic methods. The combustor boundary conditions and the effusion plate geometry were selected to mimic important features of real aero engine combustors. Scientists recorded unique data on wall temperatures, gas temperatures and turbulent flow field, including the area close to the effusion cooling plate. The radiation properties of the combustor tile were also measured, including estimations of the average emissivity and absorptivity at different temperatures. The data was then used to further analyse and validate results from different computational methods. NEWSMILE thus provided important data for the design of lean-burn combustors that are more environmentally friendly. Keywords Combustor, lean-burn engines, effusion cooling, cooling impingement, NEWSMILE
