CCRC Seminar - 15 March 2022

HYBRID EVENT

The talks are on:

Title: A Chemical Kinetic Study of the Reaction of OH Radical with Prenol and Isoprenol

Dr. Manuel Monge Palacios 

Research Scientist, supervised by Prof. Mani Sarathy

AbstractPrenol and isoprenol are alcohols with a double bond. Chemical species with the OH and double bond functional groups in their chemical structure are known as alkenols, and this chemial feature makes them excellent biofuel candidates and fuel additives. However, accurate rate constans describing the kinetics of the reactions that rule their oxidation and pyrolysis are not available, resulting in uncertain kinetic models. In this work, we performed a computational and experimental kinetic study to calculate the rate constants and branching ratios of the reactions of OH radical with prenol and isoprenol. We observed a convoluted reactivity trend that is ruled by the competition between the OH addition to the double bond and the hydrogen abstraction by OH pathways. A good agreement was observed between the overall calculated and measured rate constants. The branching ratios, which cannot be measured experimentally, indicate a much more prominent role of the OH addition pathways in prenol and isoprenol than in alkenes. These findings where rationalized in our theoretical kinetic study by means of variational transition state theory calculations with multi-structural torsional anharmonicity and tunneling corrections. 

Bio:  Manuel Monge Palacios is a research scientist in the group of Prof. Mani Sarathy. He obtained his Ph.D. in theoretical and computational chemistry from the University of Extremadura (Spain) on the development of analytical potential energy surfaces for the kinetic and dynamic study of gas-phase reactions. After his Ph.D. he joined the Department of Theoretical Chemistry at the University of Missouri-Columbia (USA) to work as a postdoctoral fellow in the development of new tools for the study of complex reactive systems. In 2017 he joined CCRC, where he is conducting molecular dynamic simulations, quantum chemistry and kinetic calculations for the study of gas-phase reactions of interest in combustion and atmospheric processes.

Title: Development and Evaluation of a Diaphragmless Shock Tube for Gas-phase Chemistry

Dr. Janardhanraj Subburaj

Postdoctoral Fellow, supervised by Prof. Aamir Farooq

Abstract: Shock tubes have been routinely used to generate reliable chemical kinetic data for gas-phase chemistry. The conventional diaphragm-rupture mode for shock tube operation presents many challenges that ultimately affect the quality of chemical kinetics data. Numerous diaphragmless concepts have been developed to overcome the drawbacks of using diaphragms. Most of these diaphragmless designs require significant alterations in the driver section of the shock tube and, in some cases, fail to match the performance of the diaphragm-mode of operation. In the present work, an existing diaphragm-type shock tube is retrofitted with a fast-acting valve, and the performance of the diaphragmless shock tube is compared with the diaphragm-mode of operation. Ignition delay time measurements have been performed for three methane mixtures and two n-hexane mixtures at 10 - 20 bar and 738 - 1537 K. Driver gas tailoring technique implemented in conventional shock tubes to obtain longer test times has also been employed in the diaphragmless shock tube. The results obtained using the diaphragmless shock tube are in good agreement with those obtained using the diaphragm-mode of operation and follow the trends predicted by simulations (AramcoMech 3.0 for methane mixtures and Zhang et al.'s mechanism for n-hexane mixtures). The study presents an easy and simple method to upgrade existing conventional shock tubes to a diaphragmless mode of operation and opens up new possibilities for reliable chemical kinetics investigations.

Bio: Janardhanraj received his dual-degree (M.Sc. and Ph.D.) in Aerospace Engineering from the Indian Institute of Science (IISc) in 2016. After his Ph.D., he worked in an IISc-incubated startup on innovative shockwave-based technologies. He is presently a postdoc in Prof. Aamir Farooq’s group working on non-conventional applications of shock tubes.


Event Quick Information

Date
15 Mar, 2022
Time
12:00 PM - 01:00 PM
Venue
HYBRID EVENT B4 Level 5, 5209