Assessment of large-eddy simulation feasibility in modelling the unsteady diesel fuel injection and mixing in a highspeed direct-injection engine

Abstract

This paper aims to assess the feasibility of largeeddy simulation LES as applied to a real engine configuration. Two cases of LES were performed together with a reference Reynoldsaveraged NavierStokes RANS simulation to study their performances in the prediction of the fuel injection and mixing in a highspeed directinjection diesel engine. In addition, sensitivity of the LES results with respect to mesh resolution was investigated, as LES requires a higher mesh density and the filtering process depends on the mesh size. The LES meant that detailed information could be obtained on the fuel spray development and turbulent flow field that was not possible to capture using the RANS modelling approach. It was found that the LES captures flow structures that have a pronounced impact on the prediction of the fuel injection and mixing. Highresolution LES predicted higher liquid and vapour penetration into the cylinder, which is in better agreement with the experimental data obtained at Delphi Diesel Systems than is the RANS prediction. It was also shown that using a finer mesh in LES yields improvements in turbulent flow field prediction, at the same time reducing contribution of the modelled part of the turbulent kinetic energy. Overall, it was proved that LES is a superior alternative to the traditional RANS approach for turbulent twophase flows encountered in diesel fuel injections where flow unsteadiness is prominent. Improved predictions obtained from an advanced LES can subsequently enhance the understanding of the fuel injection process and assist the engine experimentation and design.

Keywords

mixing largeeddy simulation KIVA injection diesel

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References

Sone

Patel

Menon

‘KIVALES largeeddy simulations of internal combustion engines. Part I theory and formulation.’ Technical report CCL2001008, Georgia Institute of Technology, Atlanta, Georgia, USA, 2001.

Fureby

Alin

Wikstrom

‘Largeeddy simulation of high Reynolds number wallbounded flows.’

AIAA J. 42 (2004): 457–468.

Piomelli

Balaras

‘Walllayer models for largeeddy simulations.’

A. Rev. Fluid Mech. 34 (2002): 349–374.

Orszag

A. S.

Staroselsky

Yakhot

‘Some basic challenges for large eddy simulation research.’ In LES of complex engineering and geophysical flows (Eds B. Galperin and S. Orszag), 1993, pp. 287–314 (Cambridge University Press, Cambridge).

Haworth

D. C.

‘Largeeddy simulation of incylinder flows.’

Oil Gas Sci. Technol. 54 (1999): 175–185.

Sone

Menon

‘Effect of subgrid modelling on the incylinder unsteady mixing process in a direct injection engine.’

Trans. ASME, J. Engng Gas Turbines Power 125 (2003): 435–443.

Celik

Yavuz

Smirnov

Smith

Amin

Gel

‘Prediction of incylinder turbulence for IC engines.’

Combust. Sci. Technol. 153 (2000): 339–368.

Celik

Yavuz

Smirnov

‘Large eddy simulations of incylinder turbulence for internal combustion engines a review.’

Int. J. Engine Res. 2 (2001): 119–148 DOI 10.12431468087011545389.

Pannala

Menon

‘Large eddy simulations of twophase turbulent flows.’ In Proceedings of the 36th Aerospace Sciences Meeting and Exhibit, Reno, Nevada, USA, 1215 January 1998, paper AIAA1998163 (AIAA, Reston, Virginia).

10.

Amsden

‘KIVA3V a blockstructured KIVA program with blockstructured mesh for complex geometries.’ Report LA13313MS, UC1412, Los Alamos National Laboratory, Los Alamos, New Mexico, USA, 1997.

11.

Valentino

Jiang

Zhao

‘A comparative RANSLES study of transient gas jets and sprays under diesel conditions.’

Atomization Sprays 17 (2007): 451–472.

12.

Huijnen

Somers

L. M. T.

Baert

R. S. G.

de Goey

L. P. H.

‘Validation of the LES approach in KIVA3V on a square duct geometry.’

Int. J. Numer. Meth. Engng 64 (2005): 907–919.

13.

Smith

Celik

Yavuz

‘Investigation of the LES capabilities of an arbitrary LagrangianEulerian ALE method.’ In Proceedings of the 37th Aerospace Sciences Meeting and Exhibit, Reno, Nevada, USA, 1114 January 1999, paper AIAA990421 (AIAA, Reston, Virginia).

14.

Sterno

Greeves

Tullis

Jiang

Zhao

‘Simulation of the airfuel mixing of an HSDI diesel engine Part 1 a new dense spray vapour coupling submodel.’

Proc. IMechE, Part D J. Automobile Engineering 220 (2006): 1793–1805 DOI 10.124309544070JAUTO390.

15.

Pomraning

‘Development of large eddy simulation turbulence models.’ PhD Thesis, University of Wisconsin Madison, Madison, Wisconsin, USA, 2000.

16.

Valentino

‘Numerical simulations of transient gas and spray jets under diesel conditions.’ PhD Thesis, School of Engineering and Design, Brunel University, Uxbridge, Middlesex, UK, 2006.

17.

Menon

Yeung

P.K.

Kim

W.W.

‘Effect of subgrid models on the computed interscale energy transfer in isotropic turbulence.’

Comput. Fluids 25 (1996): 165–180.

18.

Devesa

Moreau

Poinsot

‘Large eddy simulations of jettumble interaction in a GDI model engine flow.’ SAE paper 2004-01-1997, June 2004.

19.

Jhavar

Rutland

C. J.

‘Using large eddy simulations to study mixing effects in early injection diesel engine combustion.’ SAE paper 2006-01-0871, 2006.

20.

Kimura

Kosaka

Matsui

‘A numerical simulation of turbulent mixing in transient spray by LES comparison between numerical and experimental results of transient particle laden jets.’ SAE paper 2004012014, 2004.

21.

Jakirli

Hanjali

Tropea

‘Modeling rotating and swirling turbulent flows a perpetual challenge.’

AIAA J. 40 (2002): 1984–1996.

22.

Moureau

Barton

Angelberger

Poinsot

‘Towards large eddy simulation in internalcombustion engines simulation of a compressed tumble flow.’ SAE paper 2004011995, 2004.

23.

De Villiers

Gosman

A. D.

Weller

H. G.

‘Large eddy simulation of primary diesel spray atomization.’ SAE paper 2004010100, 2004.

24.

Birouk

Gokalp

‘Current status of droplet evaporation in turbulent flows.’

Prog. Energy Combust. Sci. 32 (2006): 408–423.