초고속 터보기계의 회전 속도에 대한 공력-소음 연구

Abstract

This study is to numerically investigate the Aero-Acoustics of Turbocharger compressor. The turbocharger compressor is high-speed turbomachinery that rotates faster than 200,000 RPM. The Aero-Acoustics with five different rotational speeds (120,000, 150,000, 180,000, 200,000, and 220,000 RPM) is used herein. The fluid domain is designed by CATIA V5R21 and analyzed by ANSYS FLUENT V19.1 with compressible momentum equation. The Pressure-velocity coupling method of the solver is the coupled algorithm and calculated by a pressure-based method. Numerical analysis of the aero-acoustics by broadband noise sources model provides calculated sound-source and acoustic-level based on steady RANS. At the industrial site, it is important to quickly analyze the noise source. APL (Acoustic Power Level) with five different rotational speeds and sound characteristics based on flow factor at the compressor wheel was numerically calculated for the noise-based design. The maximum APL is located at blade tips in case of 120,000, 150,000 and 180,000 RPM. In the case of 200,000 RPM, the maximum APL is located at splitter tips. At more than 220,000 RPM, the maximum APL is located at the balancing cutting section of the wheel. In order to optimally design the high-speed turbomachinery, cutting sections and side locations of the wheel are essential factors to reduce physical noise.