This study was carried out with an objective to develop a 3D simulation methodology for rotary engine combustion study and to investigate the effect of recess shapes on flame travel within the rotating combustion chamber and its effects on engine performance. The relative location of spark plugs with respect to the combustion chamber has significant effect on flame travel, affecting the overall engine performance. The computations were carried out with three different recess shapes using iso-octane (C8H18) fuel, and flame front propagation was studied at different widths from spark location. Initially, a detailed leakage study was carried out and the flow fields were compared with available experimental results. The results for first recess with compression ratio 9.1 showed that the flow and vortex formations were similar to that of actual model. The capability of the 3D model to predict the combustion reaction rate precisely as that of practical engine is presented with comparison to experimental results. This study showed that the flame propagation is dominant toward the leading apex of the rotor chamber, and the air/fuel mixture region in the engine midplane, between the two spark plugs, has very low flame propagation compared to the region in the vicinity of spark. The air/fuel mixture in midplane toward the leading apex burns partially and most of the mixture toward the trailing apex is left unburnt. Recommendations have been made for optimal positioning of the spark plugs along the lateral axis of the engine. In the comparison study with different recess shapes, lesser cavity length corresponding to a higher compression ratio (CR) of 9.6 showed faster flame propagation toward leading side. Also, mass trapped in working chamber reduced and developed higher burn rate and peak pressure resulting in better fuel conversion efficiency. Third recess with lesser CR showed reduced burn rates and lower peak pressure.

References

References
1.
Hamady
,
F.
,
Schock
,
H.
, and
Stueckon
,
T.
,
1989
, “
Air Flow Visualization and LDV Measurements in a Motored Rotary Engine Assembly—Part 1: Flow Visualization
,”
SAE
Technical Paper No. 900030.
2.
Danieli
,
G. A.
,
Keck
,
J. C.
, and
Heywood
,
J. B.
, “
Experimental and Theoretical Analysis of Wankel Engine Performance
,”
SAE
Technical Paper No. 780416.
3.
Bracco
,
F. V.
, and
Sirignano
,
W. A.
,
1973
, “
Theoretical Analysis of Wankel Engine Combustion
,”
Combust. Sci. Technol.
,
7
(
3
), pp.
109
123
.
4.
Grasso
,
F.
,
Wey
,
M.-J.
,
Bracco
,
F. V.
, and
Abraham
,
J.
,
1987
, “
Three-Dimensional Computations of Flows in a Stratified Charge Rotary Engine
,”
SAE
Technical Paper No. 870409.
5.
Shih
,
T. I.-P.
,
Yang
,
S.-L.
, and
Schock
,
H. J.
,
1986
, “
A Two-Dimensional Numerical Study of the Flow Inside the Combustion Chamber of a Motored Rotary Engine
,”
SAE
Technical Paper No. 860615.
6.
Raju
,
M. S.
, and
Willis
,
E. A.
,
1990
, “
Analysis of Rotary Engine Combustion Processes Based on Unsteady, Three-Dimensional Computations
,”
AIAA
Paper No. 90-0643.
7.
Jeng
,
D.
,
Hsieh
,
M.
, and
Lee
,
C.
, “
The Numerical Investigation on the Performance of Rotary Engine With Leakage, Different Fuels and Recess Sizes
,”
SAE
Technical Paper No. 2013-32-9160.
8.
Izweik
,
H. T.
,
2009
, “
CFD Investigations of Mixture Formation, Flow and Combustion for Multi-Fuel Rotary Engine
,” Ph.D. dissertation, Brandenburg Technical University at Cottbus, Senftenberg, Germany.
9.
Subramanian
,
G.
,
Vervish
,
L.
, and
Ravet
,
F.
,
2007
, “
New Developments in Turbulent Combustion Modeling for Engine Design: ECFM-CLEH Combustion Submodel
,”
SAE
Technical Paper No. 2007-01-0154.
10.
Tatschl
,
R.
,
Berg
,
E.
,
Bogensperger
,
M.
,
Sarre
,
C. H.
, and
Priesching
,
P.
,
2002
, “
CFD in IC-Engine Spray and Combustion Simulation—Current Status and Future Development
,”
5th World Congress on Computational Mechanics (WCCM V)
, Vienna, Austria, July 7–12.
11.
Tatschl
,
R.
,
Bogensperger
,
M.
,
Kotnik
,
G.
,
Priesching
,
P.
, and
Gouda
,
M.
,
2005
, “
Flame Propagation and Knock Onset Analysis for Full Load SI Engine Combustion Optimisation Using AVL FIRE
,” SAE
International Multidimensional Engine Modeling User's Group Meeting at the SAE Congress,
Detroit, MI, Apr. 10.
12.
Colin
,
O.
, and
Benkenida
,
A.
,
2004
, “
The 3-Zone Extended Coherent Flame Model (ECFM3Z) for Computing Premixed/Diffusion Combustion
,”
Oil Gas Sci. Technol.
,
59
(
6
), pp.
593
609
.
13.
Heywood John
,
B.
,
1988
,
Internal Combustion Engine Fundamentals
,
McGraw-Hill
,
New York
.
14.
Kenichi
,
Y.
,
1969
,
Rotary Engine
,
Toyo Kogyo
,
Hiroshima, Japan
.
15.
Brahmadevan
,
V. P.
,
2004
Numerical Modelling and Simulation of Rotary Engine
,” Master thesis, Cranfield University, Cranfield, UK.
16.
Abouri
,
D.
,
Zelaat
,
M.
,
Duranti
,
S.
, and
Ravet
,
F.
,
2008
, “
Advances in Combustion Modeling in STAR-CD: Validation of ECFM CLE-H Model to Engine Analysis
,”
18th International Multidimensional Engine User's Meeting at the SAE Congress
, Detroit, MI, Apr. 13.
17.
Abouri
,
D.
,
Zellat
,
M.
,
Desoutter
,
G.
,
Cano
,
A.
, and
Ravet
,
F.
,
2009
, “
Advances in Combustion Modeling in STAR-CD: A New Technique for Automatic Grid and Mesh Motion Generation Applied to Diesel Combustion and Emissions Analysis
,”
19th International Multidimensional Engine User's Meeting at the SAE Congress
, Detroit, MI, Apr. 18.
18.
Desportes
,
A.
,
Zellat
,
M.
,
Desoutter
,
G.
,
Abouri
,
D.
,
Liang
,
Y.
, and
Ravet
,
F.
,
2011
, “
A Combined Eulerian Lagrangian Spray Amortization (ELSA) in DI Diesel Combustion: Fully Coupled Eulerian/Lagrangian Spray With ECFM-CLEH Combustion Model
,”
21st International Multidimensional Engine User's Meeting at the SAE Congress
, Detroit, MI, Apr. 11
19.
Tanner
,
F. X.
,
Zhu
,
G.-S.
, and
Reitz
,
R. D.
,
2001
, “
A Turbulence Dissipation Correction to the k-Epsilon Model and Its Effect on Turbulent Length Scales in Engine Flows
,”
International Multidimensional Engine Modeling User's Group Meeting at the SAE Congress
, Detroit, MI, Mar. 4.
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