Imaging of OH* or CH* is often used for the determination of heat release in turbulent flames. Proportionality is commonly assumed, but was never proven. The study investigates which information about turbulent flame heat release rate can be obtained from OH*. It is found that although the integral heat release can be obtained from the OH* intensity, no information about the local heat release is provided by OH* due to turbulence-chemistry interactions. A model based correction method is introduced to obtain a better approximation of the local heat release of lean turbulent flames from OH* measurements. The correction method uses a statistical strain rate model, to account for the turbulence influence, and simulations of strained counterflow flames. In this way the non-linear effect of turbulence on OH* intensities and heat release rate is taken into account and corrected, heat release rate proportional OH* intensities are obtained.
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Imaging of OH* or CH* is often used for the determination of heat release in turbulent flames. Proportionality is commonly assumed, but was never proven. The study investigates which information about turbulent flame heat release rate can be obtained from OH*. It is found that although the integral heat release can be obtained from the OH* intensity, no information about the local heat release is provided by OH* due to turbulence-chemistry interactions. A model based correction method is introdu...
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