Scaling In A Ducted Rocket Combustor PDF Download

In a project to demonstrate several of the key technologies of an air-breathing propulsion unit for a medium-range air-launched missile, experiments are to be conducted on an essential component of such a unit: the ducted rocket combustor. Existing test facilities will use hardware smaller than those of the missiles of interest, so that test results on small-scale models will have to be scaled up to the larger full-sized combustors. This report details the derivation of the relevant dimensionless parameters used in the scaling process and shows how the scaling has been applied in the past to experimental data from various types of combustors. The scaling procedure is called PD-scaling, which requires that geometric similarity be maintained and that the product of the static pressure in the combustor and the length scale be held constant between the model and the full-scale combustors. Inlet velocities, fuel type, air/fuel ratios, and inlet temperatures must also be kept constant. Finally, the report shows how PD-scaling should be applied to the ducted rocket combustor tests.