This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Three-Dimensional Analysis and Modeling of a Wankel Engine
Annotation ability available
Sector:
Language:
English
Abstract
A new computer code, AGNI-3D, has been developed for the modeling of combustion, spray, and flow properties in a stratified-charge rotary engine (SCRE). The mathematical and numerical details of the new code are described by the first author in a separate NASA publication. The solution procedure is based on an Eulerian-Lagrangian approach where the unsteady, three-dimensional Navier-Stokes equations for a perfect gas-mixture with variable properties are solved in generalized, Eulerian coordinates on a moving grid by making use of an implicit finite-volume, Steger-Warming flux vector splitting scheme. The liquid-phase equations are solved in Lagrangian coordinates. The engine configuration studied was similar to existing rotary engine flow-visualization and hot-firing test rigs. The results of limited test cases indicate a good degree of qualitative agreement between the predicted and measured pressures. It is conjectured that the impulsive nature of the torque generated by the observed pressure nonuniformity may be one of the mechanisms responsible for the excessive wear of the timing gears observed during the early stages of the rotary combustion engine (RCE) development. It was identified that the turbulence intensities near top-dead-center were dominated by the compression process and only slightly influenced by the intake and exhaust processes. Slow mixing resulting from small turbulence intensities within the rotor pocket and also from a lack of formation of any significant recirculation regions within the rotor pocket were identified as the major factors leading to incomplete combustion. Detailed flowfield results during exhaust and intake, fuel injection, fuel vaporization, combustion, mixing and expansion processes are also presented. The numerical procedure is very efficient as it takes 7 to 10 CPU hours on a CRAY Y-MP for one entire engine cycle when the computations are performed over a 31×16×20 grid.
Recommended Content
Authors
Topic
Citation
Raju, M. and Willis, E., "Three-Dimensional Analysis and Modeling of a Wankel Engine," SAE Technical Paper 910701, 1991, https://doi.org/10.4271/910701.Also In
References
- Bayer, R.J. DeNagel, S.F. Steiner, J.C “Rotary Combustion Engine Hydrocarbon Source Studies,” SAE Transactions 87 3619 3636 1979
- Dimplefeld, P. Humke, A. “Heat Release Characteristics of Stratified-Charge Rotary Engines,” SAE paper 870443 1987
- Mount, R.E. Greiner, W.L. “High Performance Stratified Charge Rotary Engines for General Aviation,” AIAA paper 86-1553, AIAA/ASME/SAE/ASEE 22nd Joint Propulsion Conference Huntsville, Alabama June 1986
- Hamady, F. Schock, H. Stueckon, T. “Airflow Visualization and LDV Measurements in a Motored Rotary Engine Assembly-Part 1: Flow Visualization,” SAE Paper 900030 1990
- Ito, R. Morita, M. Mizuno, N. Hukuda, T. “A Study of Combustion in Rotary engines: observation of Combustion Flames,” Toyota Technology 27 1 Toyota Automotive Company, Ltd. Japan 1980
- Danieli, G.A. Keck, J.C. Heywood, J.B. “Experimental and Theoretical Analysis of Wankel Engine Performance,” SAE Paper 780416 1978
- Roberts, J.A. Norman, T.J. Ekchian, J.A. Heywood, J.B. “Computer Models for Evaluating Premixed and DISC Wankel Engine Performance,” SAE Paper 860613 1986
- Bartrand, T.A. Willis, E.A. “Performance of a Supercharged Direct Injection Stratified-Charge Rotary Combustion engine,” SAE Paper 103105 1990
- Bracco, F.V. Sirignano, W.A. “Theoretical Analysis of Wankel Engine Combustion,” Combustion Science and Technology 7 3 1973 109 123
- Bracco, F.V. “Theoretical Analysis of Two-Phase Wankel Engine Combustion,” Combustion Science and Technology 8 1973 69 84
- Grasso, F. Wey, M.-J. Bracco, F.V. Abraham, J. “Three-Dimensional Computations of Flows in a Stratified-Charge Rotary Engine,” SAE Paper 870409 1987
- Abraham, J. Wey, M.-J. Bracco, F.V. “Pressure Non-Uniformity and Mixing Characteristics in a Stratified Charge Rotary Engine,” SAE Paper 880604 1988
- Abraham, J. Bracco, F.V. “Comparisons of Computed and Measured Pressure in a Premixed-Charge Natural-Gas-Fueled Rotary Engine,” Rotary Engine Design : Analysis and Developments , SAE SP-768 SAE Warrendale, PA 1989 117 131
- Abraham, J. Bracco, F.V. “Fuel-Air Mixing and Distribution in a Direct-Injection Stratified-Charge Rotary Engine,” SAE Paper 890329 1989
- Amsden, A.A. Ramshaw, J.D. O'Rourke, P.J. Dukowicz, J.K. “KIVA: A Computer Program for Two- and Three- Dimensional Fluid Flows with Chemical Reactions and Fuel Sprays,” LA-10245-MS Los Alamos National Laboratory Feb. 1985
- Raju M.S. Willis E.A. “Computational Experience With a 3-D Rotary Engine Combustion Model,” Proceedings of the 1990 Joint AIAA/FAA Symposium on General Aviation Systems April 11-12 1990 Ocean City, New Jersey
- Raju M.S. Willis E.A. “Analysis of Rotary Engine Combustion Processes Based on Unsteady Three-Dimensional Computations,” AIAA-90-0643, AIAA 28th Aerospace Sciences Meeting Reno, Nevada January 1990
- Launder, B.E. Spalding, D.B. Mathematical Models of Turbulence Academic press London 1972
- Spalding, D.B. “Mathematical Models of Turbulent Flames: A Review,” Combustion Science and Technology 13 1-6 1976 3 25
- Yamamoto, K. Rotary Engine Tokyo Kogyo Co., Ltd. Tokyo, Japan 1969
- Steinthorsson, E. Shih, T.I-P Schock, H.J. Stegman, J. “Calculations of the Unsteady, Three-Dimensional Flow Field Inside a Motored Wankel Engine,” SAE Paper 880625 1988
- Raju, M.S. “AGNI-3D: A Computer Code for the Three-Dimensional Modeling of a Wankel Engine,” International Conference on Computers in Engine Technology London, United Kingdom
- Abu Elleil, M.M. “Theoretical and Experimental Investigation of the Pre-Combustion Period Events of Fuel Droplets in Gas Turbine Combustion Chambers,” Ph. D. Thesis Cairo University Cairo, Egypt June 1984