A DCAMM seminar will be presented by
Dr. Khushboo Pandey
Lecturer in Experimental Thermofluids,
School of Engineering, University of Edinburgh, Great Britain
Abstract:
The pressing need to reduce aviation carbon footprint and the drive towards sustainability has propelled several research endeavours to develop new liquid fuel combustion concepts and fine-tune existing technologies. The combustion of liquid-fuel droplets has been one of the building blocks of combustion research, striding from a fundamental understanding of flame dynamics, atomization, and vaporization, to the design of next-generation fuel injectors. Unravelling the mass and heat transfer mechanisms at the droplet level controls global phenomena such as mixing, combustion instability, and pollutant formation in any system. In the first part of my talk, I will focus on the experimental investigation of nanofuel droplet combustion and flame dynamics. Nanofuels utilize the ‘liquid-fuel extender’ technique of adding metal and metalloid nanoparticles to conventional fuels like Jet-A. I will present the possible mechanisms responsible for internal boiling, its definitive effect on droplet shape deformations, secondary atomization, and the average flame heat release rate for low-vapor pressure and high-vapor pressure nanofuels. As a multi-phase system, nanofuel droplets exhibit heterogeneous nucleation leading to the formation of vapor bubbles. These vapor bubbles grow and eject from droplet-free surfaces, opening a new pathway of secondary atomization. The second part of the talk will focus on the large-scale combustors operated with liquid fuels, such as the Lean Azimuthal Flame (LEAF) combustor. Such technologies are reactive multi-phase systems; hence, their operability limits and global behaviour might be predicted from the underlying physics of their droplets, i.e., transport and combustion of droplets/droplet clusters. For instance, the ratio of spray evaporation and convective timescales in the LEAF combustor is significant in predicting the flame topology. Here, I will talk about the spatiotemporal scales, spray Sauter mean diameters (SMDs), convective length scales, and convective/mixing timescales, which are pivotal for understanding the flame stability and combustor operability limits. Furthermore, the talk will focus on the fuel flexibility of the LEAF concept and its full hydrogen operation.
Danish pastry, coffee and tea will be served 15 minutes before the seminar starts.
All interested persons are invited