Studies of Injection of Jet Fuel at Supercritical Conditions
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- 作者：Thammarat Doungthip ; Jamie S. Ervin ; Theodore F. Williams ; and Jarrod Bento
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2002
- 出版时间：November 13, 2002
- 年：2002
- 卷：41
- 期：23
- 页码：5856 - 5866
- 全文大小：1096K
- 年卷期：v.41,no.23(November 13, 2002)
- ISSN：1520-5045
文摘
At temperatures above 400 
C and at fuel system pressures, JP-8 and Jet A jet fuels exist assupercritical fluids. Fuel nozzles operating under conventional aircraft (subcritical) conditionsatomize liquid fuel streams into droplets. The physical injection and mixing mechanismsassociated with a nozzle operating under supercritical conditions are very different from thoseoccurring under subcritical conditions. The current research examines the flow of fuel atsupercritical conditions through a simple nozzle into a region that is also at supercriticalconditions. Schlieren images of supercritical jet fuel exiting a simple nozzle into an opticalchamber are presented. Computational fluid dynamics simulations of the flow were performedusing n-decane as a surrogate fuel because it has a critical temperature and pressure similar tothe pseudo critical temperature and pressure of the jet fuel sample used in the experiments.The results of the computational fluid dynamics simulations and the measurements obtainedfrom the recorded images show that n-decane is a reasonable surrogate for Jet A fuel forpredictions of the spreading angle and jet penetration length. Measurements and computationshow that jet penetration and spreading angle are dependent on the fuel exit temperature andmass flow rate. In addition, it was found that the penetration depth of a supercritical jet intothe optical chamber is less than that for a subcritical jet with the same fuel mass flow rate andpressure conditions.
C and at fuel system pressures, JP-8 and Jet A jet fuels exist assupercritical fluids. Fuel nozzles operating under conventional aircraft (subcritical) conditionsatomize liquid fuel streams into droplets. The physical injection and mixing mechanismsassociated with a nozzle operating under supercritical conditions are very different from thoseoccurring under subcritical conditions. The current research examines the flow of fuel atsupercritical conditions through a simple nozzle into a region that is also at supercriticalconditions. Schlieren images of supercritical jet fuel exiting a simple nozzle into an opticalchamber are presented. Computational fluid dynamics simulations of the flow were performedusing n-decane as a surrogate fuel because it has a critical temperature and pressure similar tothe pseudo critical temperature and pressure of the jet fuel sample used in the experiments.The results of the computational fluid dynamics simulations and the measurements obtainedfrom the recorded images show that n-decane is a reasonable surrogate for Jet A fuel forpredictions of the spreading angle and jet penetration length. Measurements and computationshow that jet penetration and spreading angle are dependent on the fuel exit temperature andmass flow rate. In addition, it was found that the penetration depth of a supercritical jet intothe optical chamber is less than that for a subcritical jet with the same fuel mass flow rate andpressure conditions.