EFFECT OF INTERCHANGING PROPELLANTS ON ROCKET COMBUSTOR PERFORMANCE WITH COAXIAL INJECTION

摘要

The effect of reversing propellants in coaxial injection on combustor performance was determined with a nominal-200-pound-thrust rocket combustor burning gaseous hydrogen with liquid oxygen. Reversing propellants refers to the change from oxidant in the tube to fuel in the tube.nThe effect of this change was determined by measuring characteristic-velocity efficiency for a combustor having two interchangeable injectors. The injectors were designed so that the propellants could be reversed without changing their respective injection flow areas. The -performance was evaluated for three chamber lengths over a range of oxidant-fuel weight ratios from about 1.5 to 10 and for various total propellant flow rates.nHigher performance was obtained when the liquid oxygen was injected from the annulus. Comparison of the data with those from analytical studies indicated that the performance could be reasonably correlated with a turbulent-mixing model, but a vaporization-limited model could not reasonably correlate the data for the tubular oxygen injection system.nIt was also observed that the combustion noise level was lower with annu-larly injected liquid oxygen. Also, with annular oxygen injection, the injector face was less subject to high heat-transfer rates.