Multidimensional Calculations for a Two-Stroke-Cycle Engine: A Detailed Scavenging Model Validation

A multidimensional model of scavenging in a loop-scavenged two-stroke-cycle engine has been validated through detailed comparisons between computed and measured mean and rms velocities in a commercially available engine under motored operating conditions. The laser-Doppler velocimetry (LDV) measurement database constitutes one of the most complete characterizations of in-cylinder flows currently available. A novel feature of the calculations is that flow in the coupled intake-port/in-cylinder/exhaust-port system including a simplified crankcase is calculated. Through systematic variations in initial conditions and geometric configuration, the modeling suggests plausible explanations for some of the (at first sight) unexpected features found in the LDV measurements.