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Atomization and Sprays

Journal of the International Institutes for Liquid Atomization and Spray Systems

ISSN for PRINT: 1045-5110

Institutional price:	$787.00
Issues per year:	8

Best Paper Award Selection - Editorial Board Site

2006, Volume16

128 pages

Issue price - $80.00

OPTICAL MEASUREMENTS OF THE REACTING TWO-PHASE FLOW IN A REALISTIC GAS TURBINE COMBUSTOR AT ELEVATED PRESSURES

Thomas Behrendt
German Aerospace Center (DLR), Institute of Propulsion Technology, Linder Höhe, D-51147 Cologne, Germany

Martin Carl
German Aerospace Center (DLR), Institute of Propulsion Technology, Linder Höhe, D-51147 Cologne, Germany

Johannes Heinze
German Aerospace Center (DLR), Institute of Propulsion Technology, Linder Höhe, D-51147 Cologne, Germany

Christoph Hassa
DLR—German Aerospace Center, Institute of Propulsion Technology, Cologne, Germany

ABSTRACT

A rectangular sector of a realistic axially staged gas turbine combustor of Rolls-Royce Deutschland was operated at elevated pressures. Optical measurements of the reacting two-phase flow were performed using phase Doppler anemometry (PDA) and two planar light sheet techniques, laser-induced fluorescence (LIF) and Mie scattering. Beside the interpretation of the results of the measurements, the experience gathered with the techniques is analyzed with respect to the applicability, the accuracy, and the kind of information they deliver. The constraints, e.g., limited optical access, combustor with several injectors in line, and strong soot luminescence, affecting the optical setup for PDA measurements are discussed. The PDA measurements were conducted at a combustor inlet pressure of p = 6 bar. With an estimated error in the size measurement of up to Δ = 10% caused by the change of the refractive index, it was still possible to obtain quantitative results of the mean diameter. The error of the liquid volume concentration is higher and difficult to assess. Beside the unknown refractive index of the droplets, the constantly changing size and shape of the measurement volume due to beam steering effects contributed significantly to the measuring error. Images of the planar Mie scattering are used as a consistency check of the PDA data. The light sheet techniques deliver supplementary information. Imaging of kerosene LIF of an isothermal spray at atmospheric pressure was used to calculate the liquid volume concentration. A comparison with results from PDA measurements revealed a good agreement. Under reacting conditions, kerosene LIF was limited to qualitative information on the distribution of liquid and vaporized fuel mainly because of the temperature dependency of the fluorescence quantum yield. At higher pressure, the applicability of LIF was limited by the absorption of the UV laser light in the dense spray. Imaging of the planar Mie scattered light was possible at combustor inlet pressures up to p = 20 bar, giving qualitative information on the distribution of the liquid fuel.