NOx Abatement via Water Injection in Aircraft-Derivative Turbine Engines

Abstract

The results of analytical and experimental investigations to develop efficient and reliable water injection methods for reducing the nitrogen oxides (NOx) levels of the LM2500 and LM5000 engines are presented. These aircraft-derivative turbine engines are equipped with compact annular combustors. In these investigations, various methods of injecting water into the combustor primary zone were evaluated in combustor and engine tests to identify methods with minimal water flow requirements for a given degree of NOx abatement. Primary emphasis was focused on the development of methods of injecting liquid water into the engines when operating with distillate fuels. Methods of injecting both liquid water and steam when operating with natural gas were also investigated. The impacts of water injection on combustor and engine performance and operability were additionally assessed. Satisfactory accommodation of water/fuel weight ratios above unity and associated NOx level reductions as high as 90 percent were demonstrated.