Session: 34-07 Centrifugal, combustor, and bearing methods

Paper Number: 121039

121039 - Analysis of the Inlet Recirculation Phenomenon in a High-Speed Industrial Centrifugal Compressor: Experimental and Computational Study 

This research paper presents an investigation of the local flow instability known as inlet recirculation in a high-speed industrial centrifugal compressor. This phenomenon might appear when a compressor operates lower than the design mass flow rate and approaches the surge line. The study combines experimental measurements with a 3D steady-state Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) model using the k-ω Shear Stress Transport turbulence model. The single-passage CFD model was validated against the experimental data at the design point and extended to off-design conditions near the surge line. The results indicate that as the mass flow rate decreases and approaches the surge line, the compressor experiences the onset of the inlet recirculation. This recirculation leads to the formation of separation zones and irregularities in the flow field within the impeller and diffuser, negatively affecting the compressor performance and efficiency. The inlet recirculation is quantitatively analyzed, and the blockage it causes is determined. It was found that inlet recirculation can account for approximately 9% of the compressor mass flow rate and can block up to 38% of the flow area at the impeller inlet. Also, the expansion of the inlet recirculation zones was growing in two phases, showing significant radial and streamwise growth as the inlet blockage increased. For lower inlet blockage, the radial growth dominated the streamwise growth. While the streamwise growth increased significantly with relatively constant radial expansion at the higher inlet blockage.

Presenting Author: Tariq Ullah Institute of Turbomachinery, Lodz University of Technology

Presenting Author Biography: I am a dynamic professional with a global mindset, navigating diverse projects across Finland, Poland, South Korea, and Pakistan. With a passion for cross-cultural collaboration and a commitment to delivering impactful results, I thrive on tackling intricate engineering challenges, with a strong focus on turbomachinery and aerodynamics. My recent work includes investigating fluid flow instabilities in centrifugal compressors and exploring vertical-axis wind turbines for sustainable energy. This research is part of my six months of research in Finland, focusing on a local instability of inlet recirculation in a high-speed industrial centrifugal compressor.

Authors:

Tariq Ullah Institute of Turbomachinery, Lodz University of Technology
Merle Klüver School of Energy Systems, Lappeenranta–Lahti University of Technology
Ahti Jaatinen-Värri School of Energy Systems, Lappeenranta–Lahti University of Technology
Teemu Turunen-Saaresti School of Energy Systems, Lappeenranta–Lahti University of Technology
Krzysztof Sobczak Institute of Turbomachinery, Lodz University of Technology
Grzegorz Liskiewicz Institute of Turbomachinery, Lodz University of Technology