| Summary: | 碩士 === 國立成功大學 === 機械工程研究所 === 82 === The lack of energy and the rise of environment protection
thought have made people focus on the problems that how to
eco- nomize on energy and to reduce the pollutant emission. For
the academic circles,by means of reducing the equivalent ratio
and increasing the amount of dilute gas in the combustion
chamber to economize on energy and to reduce the amount of
NOx emission have become the emphasis point of their work. In
this study,methane and a rectangle transparent combustion
chamber are used in all experiments. Furthermore, one O2-N2
mix- ture with the volume-ratio of 1:3.75 and the other CO2-
N2 mix- ture with the volume-ratio of 15%:85% are taken as
simulated air and residual gas. During this study,equivalent
ratio(i.e.,φ=0.8 ,1.0,1.1 ), residual gas fraction (i.e.,f =
0.0,0.05,0.15) , and initial pressure (i.e.,
Pi=202.5,303.8,405.0 kPa) are the experi- ment variables.
After using the technology of Schilieren High Speed
Photography and the method of Thermodynamic Two-Zone Model , we
can finally obtain the following results: 1. Equivalent ratio
has significant effect on the initial state of flame
development. The condition of slight fuel-rich shows the faster
flame propagation velocity. 2. Residual gas fraction shows
evident effect on the initial state of flame development .
As the residual gas fraction increasing , the flame
propagation velocity becomes more slowly. 3. During the
initial state of flame development , increasing in the initial
pressure will cause the negative effect on the elliptical
flame structure (i.e., laminar premixed flame),and the positive
effect on the cottony flame structure ( for the density of
flammable gas increasing). 4. During the state of energy
accumulation , at the condition of non-zero residual gas
fraction , the higher the initial pres- sure is, the longer the
reaction period will be obtained.
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