Combustion Emissions

The Science of Emissions from Alternative Fuels

Overview

The Department of Defense (DOD) is pursing numerous initiatives for reducing its fuel needs and changing the mix of energy sources that it uses. Additionally, scarce energy resources, stricter environmental requirements, worldwide air traffic growth, and rising fuel prices all lead to an increasing interest in alternative jet fuels. The aviation industry currently mandates that potential alternative fuels should be completely interchangeable with the petroleum derived fuels without the need to modify the aircraft engines or other parts. A fuel is acceptable if the fuel’s physical properties fall within the acceptable range (ASTM D4054) and satisfy other characteristics of the current petroleum derived jet fuels. However, new alternative jet fuels derived from micro-organisms, pyrolysis oil, and alcohols have an unusual molecular distribution relative to the current approved fuels. The gas phase kinetics and hence, the combustion behavior, is affected by the fuel composition. This necessitates the need to understand the chemical and physical effects of fuel molecular structure on the combustion behavior. 

The experimental investigation at Penn State is a part of a collaborative Department of Defense-Industry-University research program. The specific objectives of this program is to establish a science base needed to develop accurate models for total unburnt hydrocarbon (UHC), hazardous air pollutants (PAHs), particulate matter and CO emissions from aviation gas turbine engines burning alternative fuels and establish a science based methodology for selecting practical alternative fuels that minimize emissions. The study at Penn State involves understanding the emissions in jet flames under non-remixed and rich-premixed conditions, and testing the effect of fuel volatility on emissions in a high-pressure model gas turbine combustor. The jet flames are studied to minimize effects of turbulence–chemistry interactions, which could mask the direct chemical effects of changes in fuel composition. The experiment in model gas turbine combustor replicates the complexity of bulk mixing, turbulent mixing, and spray as is present in a real combustor operating on liquid fuels. This work involves application of laser diagnostic techniques: laser extinction, laser induced incandescence (LII), and laser induced fluorescence (LIF).  

Publications

Makwana, A., Iyer, S., Linevsky, M., Santoro, R., Litzinger, T., O’Connor, J. (2017) “Effects of fuel volatility on emissions in a jet flame and a model gas turbine combustor,” Journal of Engineering for Gas Turbines and Power, in press

Wang, Y., Makwana, A., Iyer, S., Linevsky, M., Santoro, R., Litzinger, T., O’Connor, J., “Effect of fuel Composition on Soot and Aromatic Species Distribution in Laminar, Co-Flow Flames, Part 1: non-Premixed FuelCombustion and Flame, in press

Makwana, A., Wang, Y., Iyer, S., Linevsky, M., Santoro, R., Litzinger, T., O’Connor, J., “Effect of fuel Composition on Soot and Aromatic Species Distribution in Laminar, Co-Flow Flames, Part 2: Partially-Premixed FuelCombustion and Flame, in press

Makwana, A., Iyer, S., Linevsky, M., Santoro, R., Litzinger, T., O’Connor, J. (2017) “Effect of aromatic fuels on aromatic species and soot distributions in laminar, co-flow, non-premixed flames at atmospheric pressure,” 10thS. National Combustion Meeting, College Park, MD

Makwana, A., A. Jain, M. Linevsky, S. Iyer, R. Santoro, T. Litzinger, Y. Xuan, J. O’Connor, (2016) “Effects of fuel structure on soot precursors in a laminar co-flow flame,” Meeting of the Eastern States Section of the Combustion Institute, Princeton, NJ

Makwana, A., Y. Wang, M. Linevsky, S. Iyer, R. Santoro, T. Litzinger, J. O’Connor, (2015) “Capturing Soot Formation with the Use of Iso-Octane as a Surrogate for Fischer-Tropsche Fuel,” in 9th U.S. National Combustion Meeting, Cincinnati, OH