TY - GEN
T1 - Mixing characteristics of cracked gaseous hydrocarbon fuels in scramjets
AU - Ravindran, Magesh R.
AU - Bricalli, Mathew G.
AU - Pudsey, Adrian S.
AU - Ogawa, Hideaki
N1 - Funding Information:
The authors would like to gratefully acknowledge the support of the CRC-P50510 Hydrocarbon Fuel Technology for Hypersonic Air Breathing Vehicles, as well as the high-performance computing support from the National Computational Infrastructure (NCI) Australia. The CRC Programme supports industry-led collaborations between industry, researchers and the community. The first author is also thankful for the support of the Australian Government Research Training Program (RTP) Scholarship.
Publisher Copyright:
© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
PY - 2018
Y1 - 2018
N2 - High-performance hydrocarbon-fuelled scramjet engines require efficient fuel-air mixing due to the relatively short flow residence time through the combustor. At high temperatures, hydrocarbon fuels react endothermically and absorb thermal energy from the surroundings. The process known as cracking becomes essential at high Mach numbers to increase the total heat-sink capacity of the fuel. This study presents the results of numerical simulations that investigate the mixing characteristics of cracked gaseous heavy hydrocarbon fuels injected through a circular, flush-wall porthole injector inclined at 45-deg to the freestream. The mixing characteristics of six fuel compositions representing various cracking efficiencies ranging from 0-100% are investigated. The mixing rates and flow structures are found to change with fuel compositions. As the cracking increases, the mixing and streamwise circulation increase for an injectant. However, the jet penetration and stagnation pressure losses decrease. The density gradients determine the strength of vorticity in the vicinity of the injector. The streamwise circulation is found to have a strong influence on the mixing and the strength of bow shock on the jet penetration. Overall, it is shown that there are mixing benefits to be gained by injecting cracked hydrocarbon fuels compared to heavy uncracked fuels in scramjets.
AB - High-performance hydrocarbon-fuelled scramjet engines require efficient fuel-air mixing due to the relatively short flow residence time through the combustor. At high temperatures, hydrocarbon fuels react endothermically and absorb thermal energy from the surroundings. The process known as cracking becomes essential at high Mach numbers to increase the total heat-sink capacity of the fuel. This study presents the results of numerical simulations that investigate the mixing characteristics of cracked gaseous heavy hydrocarbon fuels injected through a circular, flush-wall porthole injector inclined at 45-deg to the freestream. The mixing characteristics of six fuel compositions representing various cracking efficiencies ranging from 0-100% are investigated. The mixing rates and flow structures are found to change with fuel compositions. As the cracking increases, the mixing and streamwise circulation increase for an injectant. However, the jet penetration and stagnation pressure losses decrease. The density gradients determine the strength of vorticity in the vicinity of the injector. The streamwise circulation is found to have a strong influence on the mixing and the strength of bow shock on the jet penetration. Overall, it is shown that there are mixing benefits to be gained by injecting cracked hydrocarbon fuels compared to heavy uncracked fuels in scramjets.
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U2 - 10.2514/6.2018-5260
DO - 10.2514/6.2018-5260
M3 - Conference contribution
AN - SCOPUS:85056191688
SN - 9781624105777
T3 - 22nd AIAA International Space Planes and Hypersonics Systems and Technologies Conference
BT - 22nd AIAA International Space Planes and Hypersonics Systems and Technologies Conference
PB - American Institute of Aeronautics and Astronautics Inc, AIAA
T2 - 22nd AIAA International Space Planes and Hypersonics Systems and Technologies Conference, 2018
Y2 - 17 September 2018 through 19 September 2018
ER -