Experimental Study on the Turbomachinery Trailing Edge Noise Reduction Based on Linear Cascade Test with Phased Array

Abstract

This paper is one of the series study on the mechanisms of the turbulence broadband noise reduction for turbomachinery blade with the trailing edge serrations. The trailing edge noise reduction potential of compressor blade with trailing edge serrations is experimentally investigated in a linear cascade wind tunnel with 5 compressor blades. The measurement technique of the linear microphone array was used to quantify differences of sound source levels of compressor blades withand withouttrailing edge modifications. The results show that compressor cascade trailing edge noise is effectively reduced with the using of serrated trailing edge. Serrations with sharper geometry have more noise reduction potential. The Experimental results also show that compressor turbulent trailing edge noise is considerably reduced in the frequency range of 1600-5000Hz. The largest noise reduction of sound pressure level is about 2 dB with the using of serrated trailing edge in the test. The comparison of present results with the previous turbine cascade noise reduction experimental results indicated that as inflow velocity increases, the noise reduction effect of serrated trailing edge for turbine cascade becomes better, and the serration with blunt geometry have more noise reduction potential for turbine cascade, these are opposite to the results of compressor cascade.