Evaluation of Spray/Wall Interaction Models under the Conditions Related to Diesel HCCI Engines 2008-01-1632
Diesel homogeneous charge compression ignition (HCCI) engines with early injection can result in significant spray/wall impingement which seriously affects the fuel efficiency and emissions. In this paper, the spray/wall interaction models which are available in the literatures are reviewed, and the characteristics of modeling including spray impingement regime, splash threshold, mass fraction, size and velocity of the second droplets are summarized. Then three well developed spray/wall interaction models, O'Rourke and Amsden (OA) model, Bai and Gosman (BG) model and Han, Xu and Trigui (HXT) model, are implemented into KIVA-3V code, and validated by the experimental data from recent literatures under the conditions related to diesel HCCI engines. By comparing the spray pattern, droplet mass, size and velocity after the impingement, the thickness of the wall film and vapor distribution with the experimental data, the performance of these three models are evaluated. The results indicated that the predicted mean droplet diameters by HXT model are in better agreements with measurements due to the consideration of the gas density. However, the film thickness and fuel vapor distribution near the wall region are not significantly affected by the spray/wall interaction models, and all the models present inaccurate predictions relative to the experimental results.