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

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||high 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

ALE	Arbitrary Lagrangian-Eulerian
aTDC	after top dead center

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).

blah

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