Comparisons of Computed and Measured Mean Velocity and Turbulence Intensity In a Motored Rotary Engine

The first comparisons of measured and computed mean velocities, and of measured fluctuation intensities and computed turbulence intensities in a motored rotary engine are presented. The computations were performed with a recently developed three–dimensional model. The measurements were made at the Sandia National Laboratories by Dimpelfeld and Witze at several locations along the rotor housing and at two engine speeds. The measured and computed mean velocities agree to within 15% whereas the computed turbulence intensities correctly are lower than the measured fluctuation intensities by about 30% to 50%, as anticipated. Under motored conditions, the turbulence intensity tends to be rather homogeneous and of similar magnitude somewhat before and after top dead center but significantly inhomogeneous and of greater magnitude around top dead center. The comparisons suggest that predictions of mean gas velocity and of turbulence intensity can be made with the available model.