Experimental Investigation of a Solid Propellant Ducted Rocket with a Chin Type Inlet

In this study we report an experimental research on the characteristics of combustion chamber in a solid propellant ducted rocket (SPDR) with a chin type inlet. Two kinds of propellants are tested, including boron-based solid propellant and hydrocarbon solid propellant. A new configuration of the SPDR with swirling flow is proposed. Effects on combustion characteristic of swirling flow, chamber length, propellant type and equivalence ratio are conducted. Results show that combustion efficiency based on temperature rise of the SPDR with swirling flow can reach 95%, which is 7% higher than the one without swirling flow. Furthermore, the swirler used in this study offers a significant effect on thermal protection. The combustion efficiency of hydrocarbon fuel-rich propellant is lower than that of boron-based fuel-rich propellant, and the SPDR using hydrocarbon propellant suffers from an ignition delay problem. When equivalence ratio decreases, combustion efficiency of the SPDR without swirling flow remains the same, whereas combustion efficiency of the SPDR with swirling flow increases first and then decreases.