<DOC>
<DOCNO>
589
</DOCNO>
<TITLE>
some stall and surge phenomena in axial flow compressors .
</TITLE>
<AUTHOR>
</AUTHOR>
<BIBLIO>
</BIBLIO>
<TEXT>
observations of rotating stall have shown that a wide variety
of stall patterns is possible .
     hot-wire anemometer data on a multistage compressor have
shown a progressive-type stall at low speeds . the amplitude
of the flow fluctuations increases in magnitude through the first
few stages and then diminishes rapidly to a small value in the
latter stages . a stage-stacking analysis has shown that rotating
stall will exist over a large portion of the compressor map at low
speeds but will be instigated almost simultaneously with compressor
surge at high speeds .
     blades failures attributable to resonant vibrations excited by
rotating stall have been experienced in single  and multistage
compressors .
      in the stage-stacking analysis no deterioration of stage performance
due to unsteady flow resulting from stall of adjacent stages
was considered . in general, the pressure drop at the stall point
is believed to be much larger than indicated by an analytical formulation
of compressor performance . compressor surge is attributed
to a limit cycle operation about the compressor stall
point, and, as indicated in a few compressor tests and in jet-engine
tests, a small compressor discharge receiver volume may
result simply in stall of the compressor without the cyclic characteristics
of compressor surge . in this event, engine operation
will be limited because of the large drop in performance which
accompanies compressor stall  .
</TEXT>
</DOC>
