University of California - San Diego La Jolla United States
The U.S. Army Research Office ARO previously provided support to construct a High Pressure Combustion Experimental Facility HPCEF, at the Combustion laboratory of the University of California at San Diego UCSD, for carrying out experimental studies on combustion of a wide variety of gaseous and liquid hydrocarbon fuels, including commercial fuels for example JP-8 and Jet A, at pressures up to 25 bar. A notable feature of this facility is that it permits experiments to be carried out in nonuniform flows. In contrast, experiments conducted employing shock tubes and rapid compression machines, do not include the influence of flow on combustion. The HPCEF has been successfully employed to characterize combustion of many fuels in nonuniform flows at elevated pressures These studies have shown, for the first time, the influence of pressure on critical conditions of extinction of non-premixed hydrogen, methane, ethane, and ethene flames, and the influence of pressure on critical conditions of extinction and critical conditions of autoignition of reference fuels, jet fuels, and surrogates. These studies have highlighted the influence of low temperature chemistry in promoting autoignition of high molecular weight hydrocarbon fuels. In view of the success of these previous studies at elevated pressures, additional funding was received from ARO to extend the maximum operating pressure of HPCEF from 25 bar to 60 bar. These studies provide fundamental knowledge that is relevant to the Armys need for high performance propulsion systems. High temperature and high pressure are encountered in these systems. The data at elevated pressures could be employed to test predictive models required to advance current understanding of fundamental chemical processes that characterize the combustion of jet fuels.