Analysis of air-blasted kerosene vapour concentration at realistic gas turbine conditions using laser infra-red absorption

Abstract

The infra-red absorption technique (IRA) is a line-of-sight, non-intrusive laser method, that provides the relative fuel vapour concentration in a multiphase flow with evaporation at isothermal conditions. Experiments using this technique were carried out on the LPP test rig of DLR Cologne in the frame of the EU LOPOCOTEP programme. A modular air-blast injection system with variable swirl number and fuel nozzle position was tested under several realistic gas turbine flow injection conditions. The resulting atomisation (particle size, velocity and fuel placement) has been reported by Becker $&$ Hassa cite{becker-hassa-2004}. This paper focuses on the complementary results on the fuel vapour phase conducted with IRA. The technique and its specific configuration are briefly described. The different vapour concentration profiles obtained are discussed. Some configurations, that were previously found to provide a discontinuous spray using a PDA sampling reconstruction technique, are investigated more detailed. The adaptation of IRA for time-resolved measurements, the physics of the discontinuity observed in the spray and subsequent fuel vapour concentration fluctuations are discussed.