In-situ optical combustion diagnostics on a large two-stroke marine diesel engine

Sie sind hier: Homepage > Suche

In-situ optical combustion diagnostics on a large two-stroke marine diesel engine

Mayer, Stefan / Hostrup Poulsen, Hanne / Hult, Johan

Large two-stroke Diesel engines offer several challenges to successful implementation of the type of optical and laser based measurement techniques which have been applied with so much success in smaller automotive engines during the last decade. In this paper we will present the first steps taken towards implementing optical diagnostics in a full sized and fully operational two-stroke Diesel engine for marine application. Optical ports, fitted with sapphire windows, have been developed, which allow normal uninterrupted engine operation over several hours. Considerations connected with the design of those ports, which have window diameter up to 40 mm, are introduced. Results from several measurement campaigns undertaken on this optical test engine will also be presented. The evolution and movement of burning fuel clouds are visualized at high framing rates (18 kHz) using a high-speed CMOS camera. Two types of high-speed soot luminescence imaging have been performed. By simply recording all visible light, the structure and dynamics of the luminous regions can be studied. From such image sequences individual flame ignition and propagation events can be followed in a cycle-resolved fashion. In a second set of experiments two-colour pyrometry is implemented, by splitting the emitted black body radiation into two separate optical channels. These are both captured on the same highspeed camera, whereby the temperature of the soot in the flame envelope can be estimated from the ratio of the two signals. The latter approach thus provides complementary information on the temperature distribution of the luminous regions during the engine cycle.