Numerical Investigation of the Effect of High Steam Loads on the Combustion of an Academic Premixed Swirl Stabilized Combustor

Abstract

In the past, many concepts for low-pollutant combustion have been developed for stationary and aero-gas turbines. A concept that uses the benefits of steam injection in the combustor of an aero-gas turbine is the "Water-Enhanced Turbofan (WET)" under development by MTU Aero Engines AG. In this study, the effect of high steam injection on the flow field, combustion, temperature and emission of pollutants of an academic premixed swirl stabilized combustor was investigated by numerical simulations. The purpose of this work is to study and separate the chemical and thermal effect. Therefore a detailed chemical mechanism for the gas 𝐶𝐻􀬸/Air was used. An artificial species 𝑥𝐻􀬶𝑂 has been implemented which has identical thermodynamic properties as the species 𝐻􀬶𝑂. 𝑥𝐻􀬶𝑂 is only decoupled from the chemical reaction equations, with the aim that the thermal effect can be considered separately. The results show that the main effect of the added steam is the reduction of the maximum temperature. Furthermore, the addition of steam rapidly reduces 𝑁𝑂􀯫 formation due to the large dependence on the temperature. It follows that the thermal effect is dominant and the chemical effect has only a small influence on the formation of 𝑁𝑂􀯫 .