Visualization of Gaseous Fuel Mixing Behavior in Swirling Flow Premixer by Laser Induced Fluorescence

Abstract

One of the most promising approaches to reduce NOx emissions is based on the adoption of lean premixed flames. It is needed to obtain the ideally homogeneity of the air/fuel mixture. This study is aiming to clarify factors that have influence on mixing process of gaseous fuel with air by analyzing the instantaneous concentration of non-reactive fields of mixed gaseous fuel by laser-induce fluorescence (LIF). We showed usefulness of the acetone-LIF instantaneous measurement method to visualize instantaneous mixture field of gaseous fuel and air in swirling flow field using a high power laser system. Instantaneous concentration distributions using LIF show that a peak concentration decreases and the location moves outward with increase of height from exit of the fuel nozzle by swirling flow. It is clarified that deviation of concentration fluctuation decreases and the peak location moves outward as the height increases. It is indicated that characteristics of instantaneous concentration distributions with parameters of air ratio and vane angle.