A comparative study of intake and exhaust port modeling strategies for scale-resolving engine simulations

Due to their capability to capture cycle-to-cycle variations and sporadically occurring phenomena such as misfire and knock, scale-resolving simulations are becoming more and more important for internal combustion engine simulations. Compared to the frequently used unsteady Reynolds-averaged Navier-Stokes approaches, scale-resolving simulations require significantly greater computational costs due to their high spatial and temporal resolution as well as the need to compute several cycles to obtain sufficient statistics. It is well established that the appropriate treatment of boundary conditions is crucial in scale-resolving simulations and both temporally and spatially resolved fluctuations must be prescribed. However, different port modeling strategies can be found in the literature, especially with respect to the extent of the computational domain (boundary close to the flange vs. the entire system up to the plenum) and the numerical treatment of the intake/exhaust when the valves are closed (enabled vs. disabled). This study compares three different port modeling strategies, namely a long ports version, a short ports version and a version with short and temporarily disabled ports based on the well-established Darmstadt benchmark engine. The aim is to identify the requirements for scale-resolving simulations in terms of the treatment of the intake and the exhaust ports to obtain accurate statistics (mean and variance) and cycle-to-cycle variations of the in-cylinder flow field.

[1]  C. Hasse,et al.  Numerical investigation of cyclic variations in gasoline engines using a hybrid URANS/LES modeling approach , 2010 .

[2]  Christian Hasse,et al.  Detached eddy simulation of cyclic large scale fluctuations in a simplified engine setup , 2009 .

[3]  C. Rhie,et al.  Numerical Study of the Turbulent Flow Past an Airfoil with Trailing Edge Separation , 1983 .

[4]  Johannes Janicka,et al.  On the Validation of Large Eddy Simulation Applied to Internal Combustion Engine Flows Part II: Numerical Analysis , 2014 .

[5]  Lars Davidson,et al.  Using Isotropic Synthetic Fluctuations as Inlet Boundary Conditions for Unsteady Simulations , 2007 .

[6]  Anne Cadiou,et al.  Large Eddy Simulation of the Generation and Breakdown of a Tumbling Flow , 2007 .

[7]  Johannes Janicka,et al.  Analysis of cyclic variations of liquid fuel-air mixing processes in a realistic DISI IC-engine using Large Eddy Simulation , 2009 .

[8]  J. Borée,et al.  Spatio-temporal structure and cycle to cycle variations of an in-cylinder tumbling flow , 2011 .

[9]  E. Baum,et al.  On The Validation of LES Applied to Internal Combustion Engine Flows: Part 1: Comprehensive Experimental Database , 2014 .

[10]  Xiaofeng Yang,et al.  Large Eddy Simulation (LES) for IC Engine Flows , 2014 .

[11]  Xue-Song Bai,et al.  A semi‐implicit scheme for large Eddy simulation of piston engine flow and combustion , 2013 .

[12]  Heinz Pitsch,et al.  LES of Gas Exchange in IC Engines , 2014 .

[13]  Ali Mani,et al.  Analysis and optimization of numerical sponge layers as a nonreflective boundary treatment , 2012, J. Comput. Phys..

[14]  P. Moin,et al.  Eddies, streams, and convergence zones in turbulent flows , 1988 .

[15]  Xin Zhang,et al.  The evaluation of non-reflecting boundary conditions for duct acoustic computation , 2004 .

[16]  Gunther Brenner,et al.  Unsteady CFD simulations of a pump in part load conditions using scale-adaptive simulation , 2010 .

[17]  Alessandro D'Adamo,et al.  Investigation of Boundary Condition and Field Distribution Effects on the Cycle-to-Cycle Variability of a Turbocharged GDI Engine Using LES , 2014 .

[18]  C. Hasse,et al.  A Combined Numerical and Experimental Study of the 3D Tumble Structure and Piston Boundary Layer Development During the Intake Stroke of a Gasoline Engine , 2017 .

[19]  J. P. V. Doormaal,et al.  ENHANCEMENTS OF THE SIMPLE METHOD FOR PREDICTING INCOMPRESSIBLE FLUID FLOWS , 1984 .

[20]  Florian R. Menter,et al.  The Scale-Adaptive Simulation Method for Unsteady Turbulent Flow Predictions. Part 2: Application to Complex Flows , 2010 .

[21]  Christopher J. Rutland,et al.  Large-eddy simulations for internal combustion engines – a review , 2011 .

[22]  Lipo Wang,et al.  Testing of Model Equations for the Mean Dissipation using Kolmogorov Flows , 2010 .

[23]  Christian Hasse,et al.  Identification of Large-Scale Structure Fluctuations in IC Engines using POD-Based Conditional Averaging , 2016 .

[24]  Stefan Buhl,et al.  Spatially Resolved Experimental and Numerical Investigation of the Flow through the Intake Port of an Internal Combustion Engine , 2016 .

[25]  Thierry Poinsot,et al.  LES study of cycle-to-cycle variations in a spark ignition engine , 2011 .

[26]  P. Spalart,et al.  A hybrid RANS-LES approach with delayed-DES and wall-modelled LES capabilities , 2008 .

[27]  Gerry E. Schneider,et al.  NUMERICAL SOLUTION OF PROBLEMS IN INCOMPRESSIBLE FLUID FLOW: TREATMENT OF THE VELOCITY-PRESSURE COUPLING , 1979 .

[28]  Christian Hasse,et al.  Hybrid URANS/LES Turbulence Simulation of Vortex Shedding Behind a Triangular Flameholder , 2009 .

[29]  Konstantinos Boulouchos,et al.  Comparison of Direct and Large Eddy Simulations of the Turbulent Flow in a Valve/Piston Assembly , 2015 .

[30]  Christian Hasse,et al.  Scale-resolving simulations in engine combustion process design based on a systematic approach for model development , 2016 .

[31]  Lars Davidson,et al.  Evaluation of the {SST-SAS} Model: Channel Flow, Asymmetric , 2006 .

[32]  S. Orszag,et al.  Approximation of radiation boundary conditions , 1981 .

[33]  Jean-Baptiste Michel,et al.  A new LES model coupling flame surface density and tabulated kinetics approaches to investigate knock and pre-ignition in piston engines , 2011 .

[34]  M. Raw,et al.  Robustness of coupled Algebraic Multigrid for the Navier-Stokes equations , 1996 .

[35]  P. Spalart,et al.  Physical and Numerical Upgrades in the Detached-Eddy Simulation of Complex Turbulent Flows , 2002 .

[36]  Christopher J. Rutland,et al.  Large-Eddy simulation analysis of spark configuration effect on cycle-to-cycle variability of combustion and knock , 2015 .

[37]  F. Menter.  Two-equation eddy-viscosity turbulence models for engineering applications , 1994 .

[38]  Xiaofeng Yang,et al.  Large-eddy Simulation of Motored Flow in a Two-valve Piston Engine: POD Analysis and Cycle-to-cycle Variations , 2013 .

[39]  A. Benkenida,et al.  Towards the understanding of cyclic variability in a spark ignited engine using multi-cycle LES , 2009 .

[40]  Florian R. Menter,et al.  The Scale-Adaptive Simulation Method for Unsteady Turbulent Flow Predictions. Part 1: Theory and Model Description , 2010 .