Characteristic scale identification of recirculation zone and outlet distribution regulation for a novel triple-swirler combustor

To bridge the gap in quantifying the relationship between combustor recirculation zone characteristic scales and outlet temperature fields, this study proposes a three-dimensional identification method based on ellipsoid equivalence. By quantitatively extracting characteristic length, width, and height via cross-section analysis, a correlation between the recirculation zone vortex core scale and temperature uniformity is established. Investigations on a novel triple-swirler combustor demonstrate that a radial angle of γ=60° maximizes the characteristic height, significantly enhancing radial mixing and heat diffusion. This configuration optimizes uniformity, reducing the OTDF and RTDF to 0.20 and 0.09, respectively. It is revealed that the characteristic length controls the high-temperature zone's axial position, the height regulates the radial temperature gradient, and the width dictates circumferential uniformity. Optimal exit temperature distribution therefore requires coordinated control of the three-dimensional recirculation-zone scales, maintaining a compact axial structure while appropriately expanding the radial and circumferential scales. This study provides a quantitative theoretical framework and an engineering-oriented solution for precise control of combustor exit temperature distributions.