Experimental Investigations of the Flow Field Structure and Interactions between Sectors of a Double-Swirl Low-Emission Combustor:Effects of Main Stage Swirl Intensity and Venturi Angle

Effect of venturi angle and main stage swirl intensity on flow field and interactions were investigated using PIV.The results showed the difference between the side sector and the middle sector was caused by interactions.The interactions were stronger with the rise of the main stage swirl intensity.When the swirl intensity was 0.7 and 0.9,there was little difference of the width of the recirculation zone.But the flow field had a great difference when the swirl intensity was 0.5 and 0.7,which means that when the swirl intensity was small,the swirl intensity had a great influence on the flow field.Venturi angle had a great influence on the flow field structure and interactions when the venturi angle was big,such as 90°.The venturi angle just had a small influence on the width of the recirculation zone when the venturi angle was relatively small,such as 28°and 52°.The velocity of the center plane between two sectors(plane 3)was small.There was a recirculation zone at upstream of the center plane between two sectors(plane 3)when the swirl intensity was 0.7 and 0.9,whereas not one when the swirl intensity was 0.5.The above was induced by interactions.In addition,the velocity of plane 1,plane 3,and plane 5 when the venturi angle was 52°was smaller than that of 28°and 90°.