Nitrogen Oxide Formation Pathways in Gaseous Detonations

Abstract

The realization of efficient, stable, and safe hypersonic travel is primarily driven by the development of the underlying technologies, including high-speed propulsion systems such as detonation engines. Detonation-based propulsion systems are a transformational technology for maintaining the technological superiority of high-speed propulsion and power systems. The performance of such detonation-based propulsive devices depends heavily on the structure of an underlying detonation wave. One of the key factors that can influence the implementation of such devices for commercial and propulsion applications is the stringent emissions norms. Oxides of nitrogen are formed in significant quantities and are regarded as harmful pollutants in air-breathing propulsion systems. The present study aims to explore the underlying chemistry of nitrogen oxide formation in gaseous detonations. The primary objective of the current work is to study the chemistry of different NOx formation pathways in detonations, and therefore a simplified yet effective one-dimensional tool is used to perform numerical computations. The current work employs a one-dimensional ZND model with a detailed reaction mechanism to model the high-temperature fuel combustion and nitrogen chemistry. The computed results suggest that different NOx formation pathways are dominant under different mixture conditions, and the same should be taken into consideration while developing novel NOx mitigation strategies for detonation-based propulsive devices. The study also highlights the need for detailed chemistry modeling while evaluating the nitrogen oxide emissions from practical combustion systems.