Investigation of Vaporized Kerosene Injection and Combustion in a Supersonic Model Combustor

Abstract

Injection and combustion of vaporized kerosene was experimentally investigated in a Mach 2.5 model combustor at various fuel temperatures and injection pressures. A unique kerosene heating and delivery system, which can prepare heated kerosene up to 820 K at a pressure of 5.5 MPa with negligible fuel coking, was developed. A three-species surrogate was employed to simulate the thermophysical properties of kerosene. The calculated thermophysical properties of surrogate provided insight into the fuel flow control in experiments. Kerosene jet structures at various preheat temperatures injecting into both quiescent environment and a Mach 2.5 crossflow were characterized. It was shown that the use of vaporized kerosene injection holds the potential of enhancing fuelair mixing and promoting overall burning. Supersonic combustion tests further confirmed the preceding conjecture by comparing the combustor performances of supercritical kerosene with those of liquid kerosene and effervescent atomization with hydrogen barbotage. Under the similar flow conditions and overall kerosene equivalence ratios, experimental results illustrated that the combustion efficiency of supercritical kerosene increased approximately 10-15% over that of liquid kerosene, which was comparable to that of effervescent atomization.

Effects of Entry Conditions on Cracked Kerosene-Fueled Supersonic Combustor Performance

“…Our previous investigations (Yu et al, 2005b;Fan et al, 2006) demonstrated that the flow rates of supercritical and cracked kerosene can be metered by using a sonic nozzle as long as there is no condensation during flow acceleration and the sonic condition is maintained at the nozzle throat. Figure 5 shows the schematic of the present system for product collection and flow rate calibration.…”

“…3 kerosene along with a discharge coefficient of 0.91 for all the sonic nozzles are also plotted for comparison. This threespecies surrogate was based on the model proposed by Dagaut (2002) and was developed in our earlier investigation (Fan et al, 2006), consisting by mole of 63% n-dodecane, 30% 1,3,5-trimethylcyclohexane, and 7% n-propylbenzene. It is seen from Figure 6 that below approximately 820 K the calculated values agree well with the experimental data.…”

“…To further our understanding of the above important issues, we experimentally investigated the performance of model supersonic combustors with the injection of liquid kerosene (Yu et al, 2001(Yu et al, , 2003(Yu et al, , 2005a and vaporized=supercritical kerosene (Fan et al, 2006). The effects of fuel cracking on supersonic combustion characteristics was also explored using a specially designed kerosene heating and delivery system, which can operate up to 920 K at fuel pressure of 5.5 MPa with minimal=negligible fuel coking.…”

Performance of supersonic model combustors with staged injections of supercritical aviation kerosene

“…The associated calibration procedure has been documented elsewhere [2]. In the cases of two-stage fuel injections, two sonic nozzles of different throat diameters were installed in parallel at the exit of the second-stage heater, as shown in Fig.…”

“…During injection the supercritical fuel can be directly transformed to the gaseous state without atomization and vaporization processes. Our previous experimental investigation [2] demonstrated that the use of supercritical kerosene injection has the potential of enhancing fuel-air mixing and promoting overall burning intensity. In comparison with liquid fuel injections at similar fuel flow rates, experimental results [2,3] in a Mach 2.5 model combustor showed that the static pressure rise in the combustor with supercritical fuel injection increased by 10-15% at equivalence ratios below 0.5.…”