Stereo particle image velocimetry system for combustion and turbulence studies

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Turbulent premixed combustion is the mode of operation in many practical combustion systems such as gas turbine combustors and direct injection spark ignition engines. Current and future requirements for low emissions are expected to drive virtually all issues in the development of future gas turbine systems.  Lean premixed combustor concept for gas turbine engines appears to have the most promise for very low oxides of nitrogen emissions. Lean premixed combustion systems have an intrinsic attraction for controlling the combustion process and are the method of choice.  Fully premixed systems provide control over combustion chemistry, reaction kinetics, flame temperatures, and pollutant emissions. However, to fully benefit from these advantages, the turbulence-flame interactions should be clarified.The attempts to quantify the effects of turbulence on premixed turbulent burning velocity have encountered several challenges, both theoretically and experimentally.  Substantial progress has been made in the development of numerical codes to simulate the 3D unsteady flow structures in combustion devices. However, progress has been slower in simulating the combustion process due to a lack of a robust and computationally effective prediction model for turbulent premixed flame propagation. To overcome this problem, the structure of the turbulent flame front should be better understood. To decipher the structure of the flame fronts in turbulent combustion, three dimensional flow field information along with instantaneous scalar gradients with sufficient spatial-resolution are essential.  Instantaneous measurements of temperature and OH radical concentrations at the flame front of turbulent premixed flames are currently being measured by Rayleigh scattering and planar laser-induced fluorescence. The requested instrument, a stereo particle image velocimetry system, will provide the capability to make simultaneous measurements of three dimensional velocity field along with scalar gradients.