Improving the calculation of evaporating sprays for medium-speed marine-engine-like conditions

In order to reduce maritime transportation's greenhouse gas and pollutant emissions, marine engine manufacturers need to deepen the fundamental understanding of the injection and spray process. But little knowledge is openly available on marine engine fuel sprays, and their numerical simulation. In this paper, two-dimensional unsteady-state Reynolds-averaged Navier-Stokes simulations were performed to study evaporating high-pressure marine engine sprays, in which an injector with a nozzle diameter of 0.44 mm was used. The proposed approach was first validated using measurement data of Spray A and Spray D from the Engine Combustion Network. A satisfactory agreement with the Engine Combustion Network data demonstrated that the simulation can correctly capture the spray processes. However, a discrepancy was found when simulating the marine engine sprays. After summarizing and analyzing the values of the turbulence model constant (C-1 of the standard k-epsilon model) used from the published literature, a lower value of C-1 was adopted, and good agreement under a wide range of ambient conditions (density varying from 7.6 to 22.5 kg/m(3), and temperature varying from 700 to 950 K) was achieved. Also, the disagreement that was noted for the liquid penetration for a low-temperature case could be explained by the ligament detachment phenomenon which was captured by the computational fluid dynamics simulation