Experimental Investigation of Flowfield Characteristics of Co-Rotating Radial–Radial Swirlers Under Varying Swirl Numbers
ASME Turbo Expo 2026: Turbomachinery Technical Conference and Exposition, Milan, İtalya, 15 - 19 Haziran 2026, cilt.2026, sa.176752, ss.1-11, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Cilt numarası: 2026
- Doi Numarası: 10.1115/gt2026-176752
- Basıldığı Şehir: Milan
- Basıldığı Ülke: İtalya
- Sayfa Sayıları: ss.1-11
- Orta Doğu Teknik Üniversitesi Adresli: Evet
Özet
The swirl number is a key parameter governing the size, position, and stability of the Central Toroidal Recirculation Zone (CTRZ) and Corner Recirculation Zone (CRZ) in swirl-stabilized flows, directly influencing flame anchoring and overall combustor performance. This study experimentally investigates the flow-field characteristics of co-rotating (CO) radial–radial swirlers under isothermal cold-flow conditions across a wide range of effective swirl numbers, varied from 0.0 to 1.4 in increments of 0.2. The swirl intensity is adjusted by varying the channel orientation angles of the primary and secondary swirlers. All geometries were additively manufactured using high-precision 3D printing, enabling cost-effective and repeatable geometric modifications for parametric analysis. Two-dimensional, two-component Particle Image Velocimetry (2D2C PIV) measurements were performed downstream of the swirler exit to capture both mean and instantaneous velocity fields. The results reveal a progressive evolution of the flow structure with increasing swirl number, from an attached jet flow at S = 0.0, to a fully developed vortex breakdown and CTRZ formation at S ≥ 0.8, and finally to a dome-attached flow at S = 1.4 due to the sudden radial expansion of the flow. With higher swirl intensities, the radial expansion angle, CTRZ diameter, and reversed mass flow rate increase monotonically, indicating enhanced radial momentum and stronger central recirculation. This study establishes a systematic experimental database for understanding the fundamental flow physics of radial–radial swirler configurations, providing valuable insights for the design and optimization of swirl-stabilized combustors. The findings emphasize the effectiveness of geometric swirl control and demonstrate the potential of 3D printing as a rapid and economical prototyping tool for advanced combustion research.