Optical measurements of the reacting two-phase flow in a realistic combustor at elevated pressures

Kurzfassung

A realistic gas turbine combustor from Rolls-Royce Deutschland was operated at elevated pressures. Optical measurements of the reacting two phase flow with Phase Doppler Anemometry (PDA) and two planar light sheet techniques, laser induced fluorescence (LIF) and Mie scattering, were performed. Beside the analysis of the results of the measurements the experiences made with the techniques are analysed with respect to the applicability, the accuracy and the kind of information they deliver. The limitations leading to a non optimum optical set-up for PDA measurements are described. With an estimated error in the size measurement of up to 10% caused by the change of the refractive index it was possible to get quantitative results of the mean diameter and qualitative information of the liquid volume fraction at 6 bar combustor pressure. The light sheet techniques deliver supplementary qualitative information. At higher pressure the applicability of LIF was limited by the absorption of the UV laser light in the dense spray but imaging of the Mie scattering was possible at combustor pressures up to 20 bar.