Investigation of Unsteady Flows and Noise in Rotor-Stator Interaction with Adjustable Lean Vane

Abstract

ABSTRACT:The paper is a study of the noise reduction effects of the stator lean angle. Firstly, a numerical study has been carried out to investigate the unsteady characteristics of the flow induced by the rotor-stator interaction. To obtain the rotor"s wake, the distribution of the RMS pressure and the pressure disturbance coefficient, the compressor with an adjustable stator lean angle has been numerically studied. Then the compressor was experimentally tested at 11 different lean angles to obtain the free field noise spectra. Both the unsteady flow property and noise characteristics are discussed on the basis of the Computational Fluid Dynamics (CFD) results. The results indicate that (1) the pressure fluctuation of stator is the main source of the interaction noise; (2) the phase of rotor"s wake can be tuned by the lean angle of the stator; (3) the distribution of the first harmonic of tone noise decides the distribution of total Sound Pressure level (SPL); and (4) stator with positive lean angle has better noise reduction than negative one and the lean angle should exceed 10° for better noise reduction.

Experimental and numerical investigations on the flow characteristics of rotary machineries

“…As expected, the most intense pressure fluctuations would be associated with the high TKE levels in the corner regions approaching to the blade tip, and low TKE levels are concentrated in the central region, which was also observed in the study performed by Liu et al (2014) when they investigated the rotor-stator interaction noise in a turbo fan. Several intensive spots that occur in the high pressure fluctuation regions, which may be caused by the severe rotor-stator interaction as well as the existence of a strong shear layer between the high-speed airflow in the passage and casing surface.…”

“…Reynolds-averaged Navier-Stokes (URANS) model to evaluate the broadband noise of an axial fan in terms of the turbulent kinetic energy (TKE) distributions. Liu et al (2014) carried out a numerical study to investigate the unsteady flow characteristics induced by the rotorstator interaction. It was found that the pressure fluctuations and stator lean angles could be the main sources for the interaction noise.…”

Numerical investigation of vortex dynamics in an H-rotor vertical axis wind turbine

“…First, the VAWT has low sound emission due to its low operating speed (Simão Ferreira, Van Zuijlen, Bijl, Van Bussel, & Van Kuik, 2010). Recent studies (Liu, Ouyang, Wu, Tian, & Du, 2014) are putting efforts on reducing noise of the rotor. Iida, Mizuno, and Fukudome (2004) predicts that the noise level of VAWTs is about 70 dB which is 10 dB lower than HAWTs.…”

Inner Damping of Water in Conduit of Hydraulic Power Plant

“…Even the steady operation of a turbine generates pressure pulsations, which travel through the system. The pulsations are caused by vortex rope [1] or rotor-stator interactions when the runner blade is passing the guide vane [2]. These pulsations can induce severe vibrations of the structural parts in the system.…”