Rotating stalls in vaneless diffusers are studied from the viewpoint that they are basically two-dimensional inviscid flow instability under the boundary conditions of vanishing velocity disturbance at the diffuser inlet and of vanishing pressure disturbance at the diffuser outlet. The linear analysis in the present report shows that the critical flow angle and the propagation velocity are functions of only the diffuser radius ratio. It is shown that the present analysis can reproduce most of the general characteristics observed in experiments: critical flow angle, propagation velocity, velocity, and pressure disturbance fields. It is shown that the vanishing velocity disturbance at the diffuser inlet is caused by the nature of impellers as a “resistance” and an “inertial resistance,” which is generally strong enough to suppress the velocity disturbance at the diffuser inlet. This explains the general experimental observations that vaneless diffuser rotating stalls are not largely affected by the impeller.

1.
Abdelhamid, A. N., 1980, “Analysis of Rotating Stall in Vaneless Diffusers of Centrifugal Compressors,” ASME Paper 80-GT-184.
2.
Frigne
P.
, and
Van den Braembussche
R.
,
1985
A Theoretical Model for Rotating Stall in Vaneless Diffuser of a Centrifugal Compressor
,”
ASME Journal of Engineering for Gas Turbines and Power
, Vol.
107
, No.
2
, pp.
507
513
.
3.
Jansen
W.
,
1964
, “
Rotating Stall in Radial Vaneless Diffuser
,”
ASME JOURNAL OF BASIC ENGINEERING
, Vol.
86
, No.
4
, pp.
750
758
.
4.
Kinoshita
Y.
, and
Senoo
Y.
,
1985
, “
Rotating Stall Induced in Vaneless Diffusers of Very Low Specific Speed Centrifugal Blowers
,”
ASME JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER
, Vol.
107
, pp.
514
521
.
5.
Moore
F. K.
,
1989
, “
Weak Rotating Stall Flow Disturbance in a Centrifugal Compressor with a Vaneless Diffusers
,”
ASME Journal of Turbomachinery
, Vol.
111
, pp.
442
449
.
6.
Nagashima
T.
, and
Itoh
H.
,
1989
, “
Radial Swril Flows between Parallel Discs at Critical Flow Rate
” (in Japanese),
Journal of the Japan Society for Aeronautical and Space Sciences
, Vol.
37
, No.
425
, pp.
267
277
.
7.
Senoo
Y.
, and
Kinoshita
Y.
,
1977
, “
Influence of Inlet Flow Conditions and Geometries of Centrifugal Vaneless Diffusers on Critical Flow Angle for Reverse Flow
,”
ASME JOURNAL OF FLUIDS ENGINEERING
, Vol.
99
, pp.
98
103
.
8.
Senoo, Y., and Kinoshita, Y., 1978, “Limits of Rotating Stall and in Vaneless Diffuser of Centrifugal Compressors,” ASME Paper 78-GT-19.
9.
Tsujimoto, Y., and Acosta, A. J., 1987, “Theoretical Study of Impeller and Vaneless Diffuser Attributed Rotating Stalls and Their Effects on Whirling Instability,” Proc. IAHR Work Group on the Behavior of Hydraulic Machinery Under Steady Oscillatory Conditions, Lille, France.
10.
Tsurusaki
H.
,
Imaichi
K.
, and
Miyake
R.
,
1986
, “
A Study on the Rotating Stall in Vaneless Diffusers of Centrifugal Fans (1st. Report; Rotational Speeds of Stall Cells, Critical Inlet Flow Angle)
” (in Japanese),
JSME
, Vol.
52B
, No.
480
, pp.
2930
2938
.
11.
Tsurusaki
H.
, and
Ichihara
T.
,
1988
, “
A Study on the Rotating Stall in Vaneless Diffusers of Centrifugal Fans (4th. Report; Effect of Impellers)
” (in Japanese),
JSME
, Vol.
54B
, No.
503
, pp.
1661
1668
.
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