Experimental comparisons on injection and atomization characteristics of diesel and its six-component surrogate under different critical conditions of marine engine

The novel supercritical injection and combustion technology is thought to have the potential to achieve more efficient and cleaner combustion. In order to understand the trans/supercritical injection process and improve the accuracy of computational studies of fuel injection in the marine engine scale, a novel six-component surrogate, considering some critical properties, was developed and compared with commercial diesel with the spray experiment under sub/trans/supercritical conditions. The experiment was performed in a constant volume chamber with 300 mm inner diameter as the marine engine scale. The commercial diesel and its surrogate were injected with pressures from 60 MPa to 180 MPa into different critical conditions using optical measurement method respectively. The spray structure, liquid length, R-parameter and spray cone angles were measured and analyzed. The experimental results of both fuels were verified and compared. The results showed the injection and atomization characteristics of both fuels had excellent agreement for all conditions. Some common supercritical characteristics were found. The comb-like structure at the edge of liquid tip was observed under transcritical (T) condition. The shorter penetration, smoother periphery coupled with the thick gas-liquid mixing layers were formed under supercritical condition. The liquid length, jet development, R-parameter and spray cone angles for the diesel and its surrogate existed acceptable errors within 5%. For different critical conditions, both fuels behaved as the same variation tendency. In general, the six-component surrogate is feasible to emulate the spray and critical characteristic for trans/supercritical injection research in marine engine.