During the FelxiFuel project, different aspects of spray breakup, atomisation, ignition and combustion have been experimentally investigated with focus on fuel properties and their influence on the above mentioned characteristics. In the Spray Combustion Chamber – itself a result of earlier projects, cofunded by the Swiss Federal Office of Energy and the European Union – the injection of different fuels and different injection parameters have been investigated. To do so, new experimental methods have been developed and successfully applied. The results show large differences between light fuel oils and heavy- or residual fuel oils. The atomisation process of residual fuels is significantly slower, compared to a diesel fuel. Additonally, about 20% of the components in residual fuels do not evaporate under the thermodynamic conditions present at start of injection. The heat of the flame is necessary to evaporate
these parts of the fuel in order to ignite them.
Further, possible candidates for alternative fuels were investigated to understand the challenges the application of such fuels might implicate e.g. ignition delay or flame propagation.
The distinct arrangement of the injectors in large marine two-stroke diesel engines lead to asymmetric flow conditions at the orifices of the injector, which raised questions regarding the spray breakup. Investigations showed that spray breakup and spray penetration for injectors of this size are heavily influenced by the in-nozzle flow.
The outcome of the project helps to prepare WinGDs engines for alternative fuels and triggered a series
of internal and external follow up projects. One of them with the support of the SFOE: INFLOSCOM.