Calculation of unsteady three-dimensional flow in a model motored reciprocating engine and comparison with experiment

This paper is concerned with prediction and comparison with measurement of the three-dimensional mean flow and turbulence intensities in a model engine operating at 200 rpm and 6.7 compression ratio. The engine is equipped with a single off-centered valve. The calculations are performed with the aid of the fully-implicit EPISO finite-volume solution procedure, which is applied to the ensemble-averaged equations of motion and energy conservation. The turbulent fluxes of momentum and energy appearing therein are obtained from a compressible-flow version of the k-epsilon model. The results show that moderate agreement is obtained with the experimental data for both the axial and swirl components of the mean flow. The discrepancies are due in part to discretization errors, but undoubtedly also reflect well-known deficiencies in the k-epsilon model. The turbulence intensities during compression are not appreciably augmented above those found with axisymmetric valve configurations, and are less than half those generated when a shroud is attached to the valve.