Nonreacting Spray Characteristics for Alternative Aviation Fuels at Near-Lean Blowout Conditions

摘要

The spray characteristics of standard and alternative aviation fuels generated by a hybrid pressure-swirl airblastatomizer were studied at conditions corresponding to near-lean blowout conditions: ambient gas pressureP_(vessel)=2.07 bar, fuel temperature T_(fuel)= 322 K, and atomizing gas temperature T_(gas)=394 K. The candidatealternative fuels (C-1, C-5, C-7, and, C-8 synthetic blends) were compared to Jet-A (A-2). The drop size and dropvelocity were measured using phase Doppler anemometry at three measurement planes downstream of the swirlerexit. The representative diameters [D_(10),D_(32), and the mass mean diameter (MMD)] were used to characterize the dropsize. The drop velocity was characterized using the arithmetic mean and the root mean square. An increase in theswirler pressure drop (ΔP∕P) showed a decrease in the mean drop size and an increase in the magnitude of the axialdrop velocity. Comparing the different fuels generally showed an increase in D_(10) for higher fuel viscosity. However,definitive trends in D32 and theMMDwere not observed, based on fuel physical properties such as viscosity, surfacetension, or density.Avariation of the fuel injection pressureΔP_(Pilot) showed no significant effect for both the standardand alternative fuels. The full cone angle (obtained using shadowgraph images) was found to not vary significantlywith ΔP_(Pilot) or ΔP∕P.