Internal combustion engine flows for motored operation

Application Challenge AC2-10 © copyright ERCOFTAC 2024

Abbreviations

**Table 1:** Mesh resolution study details for the high-Reynolds number and low-Reynolds number models
Mesh	Strut	Guide vane	Runner	Draft tube	Total
High-Reynolds Coarse	3 × 10⁵	7 × 10⁵	7.6 × 10⁵	1 × 10⁶	2.76 × 10⁶
High-Reynolds Fine	3 × 10⁵	8 × 10⁵	1.1 × 10⁶	2.85 × 10⁶	5.05 × 10⁶
Low-Reynolds Coarse	—	9.3 × 10⁵	1.13 × 10⁶	1.35 × 10⁶	3.41 × 10⁶
Low-Reynolds Fine	—	9.3 × 10⁵	1.13 × 10⁶	2.66 × 10⁶	4.72 × 10⁶

ALE	Arbitrary Lagrangian-Eulerian
aTDC	after top dead center

bTDC & before top dead center\\ BDC & bottom dead center\\ CA & crank angle\\ CAD & crank angle degreeCCD charge-coupled device\\ CCV & cycle-to-cycle variation\\ CDS & central differencing scheme\\ CFD & computational fluid dynamics\\ CFL & Courant-Friedrichs-Lewy\\ ENO & Essentially Non-Oscillatory\\ ERG & exhaust-gas-recirculation\\ EVC & exhaust valve closing\\ EVO & exhaust valve opening\\ HS-PIV & hight speed particle image velocimetry\\ IC & internal combustion\\ IVC & intake valve closing\\ IVO & intake valve opening\\ LES & large eddy simulation\\ MRV & magnetic resonance velocimetry\\ PIV & particle image velocimetry\\ POV & field-of-view\\ QSOU & quasi-second-order upwind\\ QUICK & Quadratic Upwind Interpolation for Convective Kinematics\\ RANS & Reynolds-averaged Navier-Stokes\\ RMS & root mean square\\ RPM & rounds per minute\\ SAS & scale-adaptive simulation\\ SRS & scale-resolving simulation\\ SST & shear stress transport\\ TDC & top dead center\\ TUBF & Technische Universität Bergakademie Freiberg\\ TUD & Technische Universität Darmstadt\\ TVD & total variation diminishing\\ UDE & Universität Duisburg-Essen\\ URANS & unsteady Reynolds-averaged Navier-Stokes\\ WG & wall-guided\\

Introduction

The TU Darmstadt engine is an optically accessible single cylinder spark-ignition direct injection engine. It is embedded in an especially designed test bench to provide well characterized boundary conditions and reproducible engine operation. A reproducible engine operation is needed to characterize the variety of in-cylinder processes and is a prerequisite for any comparison of experiments and simulations. The in-cylinder processes are characterized using advanced laser-diagnostics to provide measurements at high spatial and temporal resolutions. The aim of this effort is, to build up a comprehensive data set

to give insights into the underlying physics for a better understanding of the relevant in-cylinder processes and
for the validation of CFD simulations especially for large eddy simulations (LES).

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Contributed by: Carl Philip Ding,Rene Honza, Elias Baum, Andreas Dreizler — Fachgebiet Reaktive Strömungen und Messtechnik (RSM),Technische Universität Darmstadt, Germany

Contributed by: Brian Peterson — School of Engineering, University of Edinburgh, Scotland UK

Contributed by: Chao He , Wibke Leudesdorff, Guido Kuenne, Benjamin Böhm, Amsini Sadiki, Johannes Janicka — Fachgebiet Energie und Kraftwerkstechnik (EKT), Technische Universität Darmstadt, Germany

Contributed by: Peter Janas, Andreas Kempf — Institut für Verbrennung und Gasdynamik (IVG), Lehrstuhl für Fluiddynamik, Universität Duisburg-Essen, Germany

Contributed by: Stefan Buhl, Christian Hasse — Fachgebiet Simulation reaktiver Thermo-Fluid Systeme (STFS), Technische Universität Darmstadt, Germany; former: Professur Numerische Thermofluiddynamik (NTFD), Technische Universität Bergakademie Freiberg, Germany