Multidimensional CFD Simulation of Diesel Spray Combustion Using Chemical Kinetics

抄録

The purpose of this study is to simulate the process from spray injection to spray combustion in a rapid compression machine (RCM) more precisely. Spray behavior and spray combustion were simulated by Generalized Tank and Tube (GTT) code which is based on KIVA code. First, the model coefficients of modified wave break-up model for liquid droplet break-up were considered using experimental results of droplet diameter and velocity obtained using a laser 2-focus velocimeter (L2F). Calculation results of spray tip penetration under atmospheric conditions were good agreement with experimental from the visualization of isothermal spray under higher injection pressure conditions. Second, multidimensional CFD simulations of diesel spray combustion using the reduced chemical kinetics were carried out under RCM experimental conditions with 900 K of ambient temperature and 4.1 MPa of ambient pressure. The modelled results were validated by comparing predictions against corresponding experimental results in RCM. The predicted and measured in-cylinder pressure were in good agreement. Ignition process of diesel spray combustion of free spray in RCM were discussed with spray break-up phenomena, entrainment structure of higher injection pressure, and OH radical formation of diesel spray combustion.