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Unraveling Chain Branching in Cool Flames
Zhihong Hu1, Cheng Xie1, Shuyao Chen1
1National Synchrotron Radiation Laboratory, and State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
Journal of the American Chemical Society
|October 2, 2024
Summary
Accurately measuring hydroperoxide decomposition rate constants is crucial for understanding cool flames and optimizing engine performance. This study provides new data that refines kinetic models for cleaner combustion.
Area of Science:
- Chemical Kinetics
- Combustion Chemistry
Background:
- Cool flames involve organic compound autoxidation, producing hydroperoxides that control chain branching rates.
- Existing kinetic models suffer from uncertainties in hydroperoxide decomposition rate constants.
Purpose of the Study:
- To accurately measure decomposition rate constants for various hydroperoxides.
- To improve the accuracy of cool-flame kinetic models for engine design.
Main Methods:
- Synthesis of diverse hydroperoxides.
- Pyrolysis experiments using a jet-stirred reactor coupled with synchrotron vacuum ultraviolet photoionization mass spectrometry.
- Theoretical calculations for rate constant validation.
Main Results:
- Structural variations in hydroperoxides showed minimal impact on decomposition rate constants.
- Experimental and calculated rate constants demonstrated good agreement.
- Ketohydroperoxide decomposition rates were found to be similar to alkyl hydroperoxides.
Conclusions:
- New, accurate rate constants for hydroperoxide decomposition have been determined.
- These findings enhance cool-flame kinetic models, reducing discrepancies in predictions.
- Improved models facilitate the design of high-efficiency, low-emission engines.
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