NATIONAL ADVISORY COMlKEEEZ FOR AERONAUTICS

An investigation was conducted t o determine the hrgortance of molecular-scale processes in the over-all. turbojet conibustion process. The effect of o x y g e n concentration of the in le t oxygen-nitrogen mixture on the canibustion efficiency of a single 533 combustor was determined for combustor-inlet pressures frm 12.0 t o 21.4 inches of mercury absolute and a range of fuel-flow rates. The combustor-inlet tempera-ture and weight-flaw ra t e of the oxygen-nitrogen mixture were held con-s t a n t a t 40 ° F and 1.0 pound per second, respectively. A t t e m p t s were made t o correlate canibustion efficiency with selected fundamental com-bustion properties and with a simplified reaction-hetics equation. At a given fuel-flow rate, combustion efficiency decreased a t an increasing rate with reduction in oxygen concentration. For the pres-sures and oxygen concentrations tested, combustion efficiency decreased with a decrease in fuel-flow rate. A t a given fuel-flow rate, combus-t i o n efficiency correlated with minFmum spark-ignition energy, flam