Uncertainty Quantification of Spray Wall Impingement Simulation

抄録

Wall wetting phenomenon in direct-injection spark-ignition (DISI) engine has been demonstrated to increase both the fuel consumption and soot emissions. The drawbacks of impinging spray become more severe under cold start conditions. However, the accuracy of the existing fuel impingement model is limited under cold condition, as the current models were only validated under high and room temperature. Therefore, this paper presents a parametric study of the spray impingement model with an aim to improve its accuracy under cold conditions. Experimental validation was performed under ultra-low plate temperature to simulate the cold start condition in cold areas. The spray structure was characterized with 2D particle image velocimetry (PIV) system. Also, laser induced fluorescence (LIF) technique was employed to measure the thickness of fuel film deposited on the impinging plate. Simulations were performed using a commercial software CONVERGE. The free spray pattern, velocity distribution of the spray and the wall film thickness are compared qualitatively and quantitatively to assess the current impingement model.