Flow dynamics of dual-stage counter-swirl combustor in different confinement spaces

Abstract Verify the numerical model and physical mesh on the basis of the experiment, and then analyze the flow dynamics of the combustion chamber of the dual-stage counter-rotating swirler based on the verified numerical method. It is found that the flow dynamics of the combustion chamber of the dual-stage counter-rotating swirler is different from that of the single-stage swirler, which is affected by the change of the confinement ratio. With the increasing of confinement ratio, the flow field characteristics of combustion chamber with the dual-stage counter-rotating swirler presented in turn the axial growth flow pattern of reflux bubble (Rc ≤ 3.8), contraction flow pattern in the middle of reflux bubble (5.3 ≤ Rc ≤ 10.6) and double reflux bubble flow pattern (Rc ≥ 19.5). In addition, this paper defines the influence factor based on the change of confinement ratio, and quantitatively studies the degree of influence of the confinement ratio variation on the length of the return area of the combustion chamber. The work of this paper deepens the understanding of the physical mechanism that influences the flow and combustion by the confinement ratio, and also provides the improvement scheme for the optimization and design of the combustion chamber with dual-stage counter-rotating swirler.