Browse Publications Technical Papers 2001-01-1236
2001-03-05

Computational Study of Joint Effects of Shear, Compression and Swirl on Flow and Turbulence in a Valveless Piston-Cylinder Assembly 2001-01-1236

The potential of single-point turbulence closure models for predicting the flow aerodynamics and turbulence in internal combustion engines (IC) was investigated by computational study of idealized valveless piston/cylinder configurations. The main flow cases considered are the swirling flow in a single stroke rapid compression machine (RCM) with flat and bowl-shaped cylinder head, as well as cyclic compression. Although still remote from a real engine, these configurations enable to analyse joint effects of major phenomena governing the aerodynamics in IC engines: shear, separation, swirl and compression/expansion. Prior to the computation of these engine-like flows, an extensive validation of applied turbulence models was performed in homogeneous and wall bounded shear flows, each featuring separately rotation, swirl and mean flow compression effects. A second-moment (Reynolds-stress) closure model with low-Re-number and near-wall modifications, validated earlier in a variety of generic flows, was consistently applied to all cases considered. The basis for the analysis is a set of dedicated experiments and direct numerical simulations (DNS), which were performed in parallel for some of the configuration considered. In addition, other experimental results found in the literature were also used for model validation. Results of computational modelling show that the time-dependent, low-Re-number second-moment closure is capable of predicting the flow and turbulence dynamics in most cases considered, well in accord with the experimental and DNS data. In contrast, the results obtained with eddy-viscosity models, which are generally used in industrial computations, show in most cases poor quality. Some fundamental deficiencies of the latter models, related to engine flows, are also discussed.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Implementation of a Single Zone k-ε Turbulence Model in a Multi Zone Combustion Model

2012-01-0130

View Details

TECHNICAL PAPER

Hybrid URANS/LES Turbulence Modeling for Spray Simulation: A Computational Study

2019-01-0270

View Details

TECHNICAL PAPER

A New Methodology to Analyze Cycle-to-Cycle Aerodynamic Variations

2002-01-2837

View Details

X