Nature of Inlet Turbulence and Strut Flow Disturbances and Their Effect on Turbomachinery Noise.
Abstract
Results of an investigation in which turbomachinery rotor sound spectra were correlated with aerodynamic measurements of the inlet turbulence, strut wake, and vortex flow strengths are reported. Aerodynamic measurements included mean velocity profiles, turbulence intensity, and axial length scales. Inlet turbulence data indicate that the major effect of flow contraction appears to be the elongation of turbulent eddies from 20 cm to 200 cm. Eddies of this size dominate the blade passing frequency (BPF) tones. Decreasing eddy size by use of a grid revelaed vortex flow strength to be the second major sound source. A doubling of vortex flow strength produced a 6 dB increase in the SPL of the first BPF. The sound pressure level showed less than a 2 dB change with doubling of wake turbulence intensity or velocity defect. A discussion of the relative importance of various sources of noise due to flow distribution at the inlet is given. This report will be submitted to the Journal of Sound and Vibration for publication. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 25, 1980
- Accession Number
- ADA084355
Entities
People
- B. Lakshminarayana
- D. E. Thompson
- R. Trunzo
Organizations
- Pennsylvania State University