Power generation by using oxyfuel combustion in a gas turbine cycle is a promising option to reduce carbon dioxide (CO 2 ) emission, while using fossil fuels. In order to use this process some significant changes to the gas turbine are required, regarding which open questions still exist. An important question is whether reliable operation with oxyfuel combustion under gas turbine conditions is possible. The paper describes experiments on partiallypremixed swirl stabilized oxyfuel flames carried out in a gas turbine model combustor at atmospheric pressure. To characterize the behaviour of the oxyfuel flames a systematic parameter study for oxidisers consisting of 20 % -40 % oxygen (O 2 ), equivalence ratios from 0.5 to 1, and powers of 10 kW to 30 kW was carried out. OH * -chemiluminescence imaging was used to visualise the flame structure and stability. The results show a strong influence of the O 2 concentration on the combustion behavior in contrast to the equivalence ratio which has only a very small effect. To obtain quantitative results, laser Raman scattering has been used on selected flames to measure simulta- neously the major species concentrations, mixture fraction and temperature.The results reveal differences in the flame stabilisation mechanism, compared to methane (CH 4 )/air flames in the same burner.

A planar solid oxide fuel cell (SOFC) operated with hydrogen at T=1123 K was equipped with an optically transparent anode flow field to apply species concentration measurements by 1D laser Raman scattering. The flow channels had a cross section of 3 mm × 4 mm and a length of 40 mm. The beam from a pulsed high-power frequency-doubled Nd:YAG laser (λ=532 nm) was directed through one channel and the Raman scattered light from different molecular species was imaged onto an intensified CCD camera. The main goal of the study was an assessment of the potential of this experimental configuration for a quantitative determination of local gas concentrations. The paper describes the configuration of the optically accessible SOFC, the laser system and optical setup for 1D Raman spectroscopy as well as the challenges associated with the measurements. Important aspects like laser pulse shaping, signal background and signal quality are addressed. Examples of measured species concentration profiles are presented.

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