1989 Fiscal Year Final Research Report Summary
A Study on Combustion in Reciprocating Internal Combustion Engines by Computational Fluid Dynamic Approach
| Project/Area Number |
63460098
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Thermal engineering
|
|---|
| Research Institution | KYOTO UNIVERSITY |
|---|
Principal Investigator |
IKEGAMI Makoto Fac. of Engineering, Kyoto University, Professor, 工学部, 教授 (70025914)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YOSHIHARA Yoshinobu Fac. of Science and Engineering, Ritsumeikan Univ., Associate Professor, 理工学部, 助教授 (30174999)
YAMANE Koji Fac. of Engineering, Kyoto Univ. Instructor, 工学部, 助手 (10210501)
SHIOJI Masahiro Fac. of Engineering, Kyoto Univ. Associate Professor, 工学部, 助教授 (80135524)
|
|---|
| Project Period (FY) |
1988 – 1989
|
| Keywords | Internal Combustion Engine / Combustion / Computational Fluid Dynamics / Simulation / Gas Flows / Combustion Chamber / Turbulence / Heat Transfer |
|---|
| Research Abstract |
The in-cylinder flows and combustion in reciprocating internal combustion engines were described by a numerical fluid dynamic method, to enable prediction of effects of various parameters such as combustion-chamber shape, ignition, injection, and gas flows. A special caution was paid to select simple but adequate submodels for turbulence, spray, and chemical reactions. The simulation programs thus developed was applied to various problems. The following results were obtained.
1. To allow the computer simulation at combustion chambers with arbitrary geometries, a new algorithm was proposed such that used finite element concept only for computational cells adjacent to wall boundaries, the remaining grid cells relying on an ordinary finite difference scheme in an orthogonal coordinate system. The proposed method was applied to elucidate flows and combustion in a reentrant chamber of a diesel engine.
2. Turbulence near the region of flame front in a spark-ignition engine was directly measured by a laser homodyne method. The obtained results show that there is only a little production of turbulence in the flame zone, because of the laminarization at increased temperature.
3. The effect of the top clearance in a deep-bowl direct-injection diesel engine was assessed based on the computer simulation. At a smaller clearance, unburnt outflow of the mixture from the bowl into the clearance space is suppressed in earlier stages of burning, and as a result unburnt raw fuel is less than at bigger clearance.
4. Heat flux through the combustion-chamber walls of diesel engines was predicted. The predicted heat flux was in good agreement with that by the empirical correlations between the Nusselt and Reynolds numbers, once a thin deposit layer on the surface was assumed.
|
