Investigation of three-dimensional cold flow field reconstruction of a triple-stage axial swirler

To reconstruct the three-dimensional (3D) cold flow field of a triple-stage axial swirler, this study uses two-dimensional (2D) particle image velocimetry (PIV) to capture flow structures across multiple axial, radial, and tangential sections. Downstream 3D flow features—velocity fields, recirculation zones, streamlines, turbulence, and vorticity distributions—are reconstructed using linear interpolation and velocity filling techniques. The key findings are as follows: (1) Interpolated data at integer–coordinate sections closely correspond to experimental results, confirming the accuracy of the linear interpolation method. (2) Flow structures from densely interpolated sections show strong agreement with original data, with maximum absolute and relative errors for all three velocity components staying within acceptable engineering tolerances. (3) The reconstructed sections exhibit flow structures consistent with the original measurements, validating the accuracy of the 3D reconstruction methods. (4) Momentum exchange between the swirler stages generates a unified clockwise swirling jet. Downstream, the flow develops a layered structure consisting of three zones: the corner recirculation zone, the high-speed swirling shear layer zone, and the central recirculation zone. Turbulent intensity and kinetic energy peak near the swirler exit and in high-shear regions. (5) Inner and outer shear layers appear as inherent characteristics of swirling flows, independent of the triple-stage design. By combining experimental PIV measurements with computational reconstruction techniques, this study characterizes the 3D cold flow dynamics of a triple-stage axial swirler. This methodology provides a novel way to transform 2D PIV data into volumetric flow information.