Experimental Assessment of a 15-N Nitrous Oxide and Ethane Thruster for Premixed and Non-Premixed Operations

Experimental Assessment of a 15-N Nitrous Oxide and Ethane Thruster for Premixed and Non-Premixed Operations

Salt Palace Convention Center, Salt Lake City, UT

• Nitrous Oxide (N₂O) has attracted significant attention as an oxidizer for next-generation small scale propulsion systems due to its non-toxic and high vapor pressure, which enables self-pressurization.  
• By combining N₂O with hydrocarbon fuels, propulsion systems can be operated either as bipropellant systems or as premixed propulsion systems.  
• N₂O-based premixed propellants, commonly known as NOFB (Nitrous Oxide Fuel Blend), require only a single propellant tank, similar to monopropellant systems, resulting in a simplified system architecture; however, their high susceptibility to flashback necessitates the incorporation of dedicated flashback prevention devices.  
• The objective of this study is to perform non-premixed and premixed combustion tests under identical operating conditions and quantitatively compare the ignition characteristics and propulsion performance of the two propellant concepts.  
• A small-scale thruster (5 – 15 N ) was designed, and ground hot-fire tests were conducted using non-premixed and premixed injectors under identical chamber and propellant flow conditions.  
• Ethane (C₂H₆) was selected as the fuel because of its high vapor pressure (39 bar at 298 K) and excellent thermal stability.