Effects of initial conditions on MILD combustion for diesel in a constant pressure combustion bomb

Abstract

The experimental and computational studies for MILD combustion of diesel were conducted in this paper. The experiment was carried out in a constant pressure bomb and the computation was completed with the SAGE combustion model. The initial condition in the experiment covers two temperatures (723 K and 773 K), two pressures (18 bar and 25 bar), with a constant fuel flow of 2 kg/h, an oxygen flow of 1 kg/h, and a wide range of carbon dioxide flow containing 35–160 kg/h. Normal combustion has bright yellow flame and MILD combustion has blue flame according to observation in the experiment. The effects of ejection ratio, initial temperature and pressure are investigated to illustrate the mechanism of MILD combustion. The results show an increase in ejection ratio and an increase in initial temperature are propitious to achieve MILD combustion, while increased pressure needs more strict requirements to realize MILD combustion. Generally, experiment results and computations have similar trends for the effects of initial conditions on MILD combustion.

Keywords

• Diesel fuel
• MILD combustion
• High pressure
• Combustion bomb