Particle Image Velocimetry (PIV), pressure, and noise measurements are used to study the effect of modifications to tongue and impeller geometries on the flow structure and resulting noise in a centrifugal pump. It is demonstrated that the primary sources of noise are associated with interactions of the nonuniform outflux from the impeller (jet/wake phenomenon) with the tongue. Consequently, significant reduction of noise is achieved by increasing the gap between the tongue and the impeller up to about 20 percent of the impeller radius. Further increase in the gap affects the performance adversely with minimal impact on the noise level. When the gap is narrow, the primary sources of noise are impingement of the wake on the tip of the tongue, and tongue oscillations when the pressure difference across it is high. At about 20 percent gap, the entire wake and its associated vorticity trains miss the tongue, and the only (quite weak) effect of nonuniform outflux is the impingement of the jet on the tongue. An attempt is also made to reduce the nonuniformity in outflux from the impeller by inserting short vanes between the blades. They cause reduction in the size of the original wakes, but generate an additional jet/wake phenomenon of their own. Both wakes are weak to a level that their impacts on local pressure fluctuations and noise are insignificant. The only remaining major contributor to noise is tongue oscillations. This effect is shown to be dependent on the stiffness of the tongue.

1.
Chu, S., Dong, R., and Katz, J., 1993, “Unsteady Flow, Pressure Fluctuation and Noise Associated With the Blade-Tongue Interaction in a Centrifugal Pump,” presented at the Symposium on Flow Noise Modeling, Measurement and Control, ASME Winter Annual Meeting, New Orleans, LA, Nov. 28-Dec. 3.
2.
Chu, S., Dong, R., and Katz, J., 1995a, “Relationship Between Unsteady Flow, Pressure Fluctuations and Noise in a Centrifugal Pump. Part A: Use of PIV Data to Compute the Pressure Field,” ASME Journal of Fluids Engineering, Vol. 117, No. 1.
3.
Chu, S., Dong, R., and Katz, J., 1995b, “Relationship Between Unsteady Flow, Pressure Fluctuations and Noise in a Centrifugal Pump. Part B: Effect of Blade-Tongue Interaction,” ASME Journal of Fluids Engineering, Vol. 117, No. 1.
4.
Cumpsty, N. A., 1989, Compressor Aerodynamics, Longman Scientific & Technical, England.
5.
Dean
R. C.
, and
Senoo
Y.
,
1960
, “
Rotating Wake in Vaneless Diffusers
,”
ASME Journal of Basic Engineering
, Vol.
82
, No.
3
, pp.
563
574
.
6.
Dong
R.
,
Chu
S.
, and
Katz
J.
,
1992
a, “
Quantitative Visualization of the Flow Within the Volute of a Centrifugal Pump. Part A: Technique
,”
ASME Journal of Fluids Engineering
, Vol.
114
, No.
3
, pp.
390
395
.
7.
Dong
R.
,
Chu
S.
, and
Katz
J.
,
1992
b, “
Quantitative Visualization of the Flow Within the Volute of a Centrifugal Pump. Part B: Results
,”
ASME Journal of Fluids Engineering
, Vol.
114
, No.
3
, pp.
396
403
.
8.
Eckardt
D.
,
1975
, “
Instantaneous Measurements in the Jet/Wake Discharge Flow of a Centrifugal Compressor Impeller
,”
ASME Journal of Engineering for Power
, Vol.
97
, No.
3
, pp.
337
346
.
9.
Hamkins
C. P.
, and
Flack
R. D.
,
1987
, “
Laser Velocimeter Measurements in Shrouded and Unshrouded Radial Flow Pump Impeller
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
109
, pp.
70
76
.
10.
Hira
D. S.
, and
Vasandani
V. P.
,
1975
, “
Influence of Volute Tongue Length and Angle on the Pump Performance
,”
Journal of Mechanical Engineering (Indian)
, Vol.
56
, pp.
55
59
.
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