Study made of noise radiation from rotor-stator interaction in axial-flow compressors. The collected data were reduced to the form of radiation patterns and frequency spectra. These data show how the radiation patterns are affected by the relative number of rotor blades and stator vanes

Copeland, W. L.

Crigler, J. L.

English

NASA Technical Reports Server

Exhaust Inlet Airflow 
December 1967	 Brief 67-10516 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Noise Study of Single Stage Compressor Rotor-Stator Interaction 
Drive Motor	 Rotor	 Stator 
Floor Level 
Noise from axial-flow compressors is a serious 
problem as it relates to the operation of jet transport 
aircraft from commercial airports. Because of the lack 
of information on the generation and propagation as-
pects of the problem, a study has been directed to-
ward evaluation of rotor-stator interaction. Far-field 
noise radiation data from several rotor-stator con-
figurations were compiled and compared where pos-
sible with available theory. 
The test compressor setup is depicted in profile 
in the figure. The compressor was driven by a variable 
speed electric motor at speeds up to 8700 rpm, cor-
responding to a tip speed of 560 fps. A microphone 
for picking up acoustic data was mounted in such a 
way that it could be moved continuously within inlet 
centerline level and one quadrant of a 12-foot radius 
azimuth circle. Airflow measurements were made with
an array of pitot static tubes located ahead of the 
stator. 
The collected data were reduced to the form of ra-
diation patterns and frequency spectra. The radiation 
patterns compare favorably with results calculated 
from theoretical considerations. These data show how 
the radiation Datterns are affected by the relative 
number of rotor blades and stator vanes. Discrete 
random noise and frequency components were ob-
served to increase in level with rotor speed and at 
essentially similar rates. The discrete frequency 
radiation patterns for a given rotor were found to 
vary with changes in stator configuration. Increased 
spacing between rotor and stator resulted in decreased 
noise levels and in elimination of most of the radia-
tion pattern individual lobes. (continued overleat) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19670000515 2020-03-11T20:56:29+00:00Z
Note: 
Inquiries concerning this innovation may be di-' 
rected to:
Technology Utilization Officer 
Langley Research Center 
Langley Station 
Hampton, Virginia 23365 
Reference: B67-10516
Patent status: 
No patent action is contemplated by NASA. 
Source: William L. Copeland 
and John L. Crigler 
(LaRC-1 37) 
Brief 67-10516	 Category 02


Noise study of single stage compressor rotor-stator interaction

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