Inlet Geometry and Equivalence Ratio Effects on Combustion in a Ducted Rocket

The scope of this study is to predict the combustion performance of a ducted rocket combustor. Connected-pipe combustion experiments and numerical analysis of the internal reacting flow in a ducted rocket combustor were conducted at various equivalence ratios with an emphasis on the air inlet geometry effect. The considered equivalence ratio in experimental and numerical investigations varied between 0.35 and 1.57 in order to reflect the variable-flow conditions of the ducted rockets. Three kinds of combustors have been used in order to evaluate the air inlet geometry effect: a two-inlet combustor with an inlet angle of 90 deg, a two-inlet combustor with an inlet angle of 180 deg, and a four-inlet combustor with an inlet angle of 90 deg. The behavior of the carbon particles within the fuel-rich gas stream was investigated and found to have a major effect on the temperature rising. The four-inlet combustor exhibited the best combustion efficiency, and the two-inlet combustors did not show large differences in terms of performance. The numerical model showed sufficient predictability within 6% accuracy in comparison with experimental temperature for all test conditions.