Revisiting the Combustion Kinetics of Di-Isopropyl Ketone: New Insights from Elevated Temperature LBV Measurements

This
study focuses on measuring the laminar burning velocity (LBV)
of the second-generation biofuel di-isopropyl ketone (DIPK) + air
mixtures using an externally heated diverging channel method at elevated
mixture temperatures. Experiments were conducted at elevated mixture
temperatures of up to 639 K across a range of equivalence ratios varying
from 0.7 to 1.3 under atmospheric pressure conditions. The obtained
LBV measurements were compared with existing experimental data and
predictions from a recently developed comprehensive chemical kinetic
model of DIPK. The results demonstrated good agreement between the
present LBV measurements and existing data, and the predictions from
the Lin model also showed a good trend of LBV values at lower mixture
temperatures (up to 393 K). However, the Lin model exhibited significant
underpredictions at elevated temperatures when compared to the present
measurements. From the sensitivity analysis, key reactions were identified,
and the rate coefficients of reaction R84 were updated from the recent
mechanism of NUIGMech1.3. Notably, the updated rate coefficients for
reaction R84: CH2 + O2 => CO2 +
2H
showed an increase in the rate constant with temperature (∼293%
at 2500 K, ∼220% at 750 K, and ∼174% at 500 K), enhancing
the LBV of DIPK + air mixtures. The updated DIPK model demonstrated
improved agreement with LBV measurements from existing literature
across various mixture temperatures and equivalence ratios, as well
as with the present experimental data at elevated temperatures. The
modification of R84 improves LBV, with a negligible impact on ignition
delay times and species mole fraction profiles.