Effect of Swirling Strength on Flow Characteristics of a Heavy-Duty Gas Turbine Annular Combustion Chamber

Abstract

Based on the self-designed annular combustion chamber of a 300 MW heavy-duty gas turbine, the ANSYS Fluent 15.0 is used to carry out numerical simulation research on the flow process in the combustion chamber. It mainly studies the influence of the swirling strength of the inlet airflow on the velocity fields in non-reacting and reacting flows, temperature field and low pollution emission in the annular combustor. It is found that two central recirculation zones with opposite directions of rotation are formed in the inlet section of the combustion chamber. Two angular recirculation zones are formed at the bosses and rotate around the bosses. The structure of the central recirculation zone is mainly affected by the swirling strength of the premixed flow from outer ring while the angular recirculation zone is affected by the flows from inner hole and outer ring. The average velocity of the reacting flow is about twice that of the non-reacting flow. The temperature on the central axis section of the combustor increases first and then decreases from the central of chamber to the wall. The average temperature of the central recirculation zone in the combustion chamber is around 2223 K. The average temperature in the near-wall region is around 2200 K. Due to the high temperature in the combustion chamber, a certain amount of NOx is generated.