Deflagration-to-Detonation Transition in Nitrous Oxide/Oxygen-Fuel Mixtures for Propulsion

Abstract

Nitrous oxide () has gained popularity as a unique oxidizer for propulsion applications due to its ability to decompose exothermically, producing nitrogen and oxygen. In the current work, the flame acceleration, deflagration-to-detonation transition, and detonation properties of bipropellant mixtures with as the oxidizer are studied for potential applications in pulsed blowdown and detonation-driven thrusters. These properties are compared with those in mixtures with oxygen () or nitrogen tetroxide () as the oxidizer. The performance of versus for detonation engine applications is investigated using theoretical Chapman–Jouguet detonation calculations of bipropellant systems with ethylene () and acetylene () as fuels. A critical requirement for the application of bipropellant mixtures to pulsed propulsion systems is rapid flame acceleration to achieve significant chamber pressure rise in a short distance with the potential for a prompt transition to detonation. This deflagration-to-detonation transition behavior of mixtures using and with and is investigated for increasing initial pressures in the experimental portion of this work. While is a highly energetic fuel with theoretically high performance, it presents serious practical storage concerns when considered for propulsion applications. These practical issues motivate investigation of as a potential alternative fuel, which is relatively easy to manage. The precompression of the bipropellant mixtures during flame acceleration is also estimated and compared.