ID 418

Experimental Analysis of Fuel Alternatives for Marine Propulsion Systems

 

Abstract:

Work Package 1 of the European Union’s HERCULES-2 project has the objective to develop an injection system allowing for fuel flexible engine operation. Such an injection system must cover the spectrum from clas-sic fuels – residuals from the petrochemical industry – to the far end marked by liquid fuels like ethanol and methanol. The Spray Combustion Chamber – a device developed and improved during earlier HERCULES-projects – was chosen to investigate the spray and combustion morphology of two fuel alternatives. As a refer-ence light fuel oil was applied and investigated with a new injector type which allows for variable flow area. Spray penetration of the alternative fuels shows strong differences, compared to classic fuels. The reason for this is expected in the lower viscosity and reduced compressibility of the alcohols, which both influence in-nozzle flow and hence spray tip penetration. The thermodynamic analysis shows a trend towards a good por-tion of pre-mixed combustion. This is a consequence of the pilot injection, which might still need some im-provement on the exact timing, in combination with the swirl velocity. But the rate of heat release looks promis-ing and for the engine tests following this year, a sound knowledge basis could be generated. For the first time CH2O-LIF was applied for the demanding conditions, present in the combustion chamber of large marine diesel engines. First signals could be recorded, but unfortunately the signal to noise ratio was far from useable. Further investigations are therefore necessary. The injector design proved a good repeatability and a stable spray pat-tern.