Effect of Gas
Exchange Processes and Mixing on Homogeneous Charge Compression
Ignition (HCCI)
Abstract:
The goal of this study is to examine the effect of gas exchange
processes and mixing on HCCI combustion. In the framework of
this study, a methodology for the simulation of the gas exchange
processes and combustion in an HCCI engine is being developed.
KIVA-3V is used to simulate the gas exchange processes and part
of the compression. The results are then used to initialize
the calculation in a multi-zone engine simulation with detailed
chemical kinetics (HCCIES by Fiveland and Assanis), which calculates
the remainder of the cycle.
Background:
The Homogeneous Charge Compression Ignition (HCCI) is currently
under widespread investigation, due to its potential to increase
thermal efficiency while greatly decreasing harmful
exhaust pollutants. There are two main reasons that make the realistic
simulation of an HCCI engine quite difficult:
- HCCI combustion
is governed by chemical kinetics, which need to be modeled accurately.
- The fuel-air
mixture in an HCCI engine is not really homogeneous and the
modeling of the gas exchange processes and in-cylinder mixing
is important.
Using a CFD code with detailed chemical kinetics for simulating
the full cycle of an HCCI engine is computationally very intensive
and the duration of a calculation can be weeks or even months.
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Researchers:
Aristotelis Babajimopoulos
Dennis Assanis
Goals
of the work:
Develop a methodology for the simulation of an HCCI engine that
gives accurate results in reasonable computational time.
- Use KIVA-3V to simulate the exhaust, the intake and part of
the compression process in a natural gas engine.
- Examine various engine operating conditions.
- Evaluate the homogeneity of the fuel-air mixture at the
end of intake or before the onset of combustion.
- Find the temperature distribution in the cylinder, divide
into zones and initialize the zones in HCCIES.
- Use HCCIES to simulate the combustion process.
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