Electric Flames

Electromagnetically Enhanced Combustion

Details

​​Recently, there has been an increased interest in studying combustion plasma due to the significant environmental effects of combustion exhaust and the possible application of ion probes (or external electric fields) in controlling the combustion and increasing the burning efficiency. However, the progress is restrained due to our limited understanding of the flame ionization processes and the evolution of ionic species concentrations in the post-flame front region or in the combustor. In addition to the numerical efforts, extensive experimental investigations related to combustion plasma formation and flame ion composition are required. 

KAUST faculty members are pursuing a 3-year long AEA (Academic Excellence Alliance) project with their colleagues from UC Berkeley on the topic of “Electromagnetically Enhanced Combustion”. Electrically and magnetically assisted combustion has been shown to reduce pollutant emissions, improve combustion efficiency, and extend the operability of combustion devices. Electromagnetic fields may be an effective and efficient mean of implementing advanced control strategies in energy conversion devices such as internal combustion engines and gas turbine combustors. This project is aimed at understanding the fundamental processes that govern these processes. We are working on providing a much-improved understanding of ion & electron chemistry and transport in a chemically reactive gaseous mixture subject to electrostatic and electro-magnetic fields. We are also formulating a set of verified and validated numerical models & codes capable of capturing the basic response of a reactive mixture to electrostatic and electro-magnetic fields. Finally, the aim is to develop and characterize a first generation of actuators and sensors exploiting weak plasmas and their interaction with electrostatic and electromagnetic fields to monitor, influence, and ultimately control combustion processes.    

The Chemical Kinetics and Laser Sensors Laboratory is working on a multi-facet diagnostic approach to study the evolution of charged species in premixed and counter-flow diffusion flames in the presence of externally applied electric fields:

1. The hydronium ion (H3O+) is one of the most important and abundant positive ions influencing the ion chemistry. This ion has its H3O+
fundamental vibrational band near 3500 cm-1. The absorption cross-section will be measured using positive column discharge in H2/O2 gas mixture. In-situ quantitative measurements of H3O+ concentration will then be carried out in laminar flames using diode-laser absorption spectroscopy with a multi-pass arrangement. 
2. Knowledge of the temperature evolution along the flame plays a critical role in evaluating the species concentration profiles. A two-color strategy based on the absorption of water vapor near 2.9 μm will be used to measure the flame temperature.
3. The proposed in-situ experimental work will be compared with and complemented by measuring complete ion profiles using molecular beam mass spectrometry (MBMS) and carefully designed extraction system.