Prediction of NOx Emissions for an RQL aero-engine combustor using a stirred reactor modelling approach

The world has witnessed a drastic techno-economic development in the last century due to which transport, trade and logistics have improved the lifestyle of the public. The Aviation industry has transformed the way of travelling across globe. Now it is more economic, comfortable and accessible to travel. Unfortunately, this revolution in aviation has brought various environmental issues; gaseous emissions and noise nuisance. These gaseous emissions disrupt the eco-system normal operating process. These gases have serious implications on the global environment and pose a great risk for human health. The NOx (NO and NO2) is a major concern; especially around the airports locality, where it can create ozone gas which is harmful to the wellbeing. In spite of much advancement in fuel-efficient and less polluting turbofan and turboprop engines, the rapid growth of air travel in recent years has contributed to an increase in total emissions. According to the ICAO, the contribution of civil aircraft to global greenhouse emissions has been estimated at around 2%. The Committee on Aviation Environmental Protection (CAEP), which assists ICAO in the formulation of new policies on aircraft noise and emissions, has presented a number of policies in the last decade in order to curb down the aviation emissions. Due to these emission regulations, the aviation industry is looking into the ways to cut down its global emission imprints.The primary objective of this paper is to assess the suitability of the stirred reactor modelling approach to predict NOx emissions of a Rich-Burn Quick-Quench Lean-Burn (RQL) combustor concept. This paper further illustrates the axial variation in the main parameters such as equivalence ratio, NOx mass fractions and temperature for a NASA test rig experiment combustor geometry from the RQL combustor model based on the stirred reactor method. The paper also comments on the NOx emission regulations development by ICAO for different operating conditions.