Closed Impeller Design 1

[cmarinelli]

Can anyone recommend a good reference for design of closed centrifugal impellers? We are reverse engineering a closed impeller for an aerospace fuel pump, and would like to optimize the design to reduce vibration.

Does anyone know if the reference listed in the Pump Engineering FAQ has a good section on closed impellers?

Thanks in advance for any assistance you can provide.

Chris Marinelli
Dynatech Aerospace

 

[PUMPDESIGNER]

The following two references are useful:
"Pump Handbook" (Karassik et al)
"Centrifugal and Axial Flow Pumps" (Stepanoff)

PUMPDESIGNER

 

[cmarinelli]

I will definitely check those out.

Thanks!
Chris

 

[25362]

It might be worthy also to take a look at Sam Yedidiah's Centrifugal Pump User's Guidebook (Chapman and Hall)
ISBN 0-412-99111-X

 

[vanstoja]

Optimization of centrifugal pump designs for vibration/noise is generally not considered in the older classical design references such as those cited above. A modern pump text dealing with vibrations is Brennan,C.E.,1994,"Hydrodynamics of Pumps". Also, for very high speed pumps typical of aerospace designs (eg. SSME hydrogen and LOX pumps), rotordynamics of centrifugal pump impellers becomes a critical factor in vibration optimization. A good recent book on this subject is Childs,D.,1993,"Turbomachinery Rotordynamics-Phenomena,Modeling,Analysis". Childs(TAMI) also provides many papers on the specifics of impeller seal dynamics design for very high speed pumps where swirl brakes and complex seal surface patterns are employed to control impeller seal-flow-induced whirl.
For centrifugal pumps, the major hydraulic vibration sources are Impeller Blade Passing(IBP) harmonics whose control requires minimum possible rotational speeds and large blade-vane cutwater clearances when vaned diffusers or inlet guidevanes are used. Vaneless diffusion is generally a better choice to eliminate IBP sources downstream of the impeller. These features are not certainly conducive to optimal hydraulic performance and one must accept performance penalties when vibration/noise is to be optimized. Open rather than closed impellers are more usual in aerospace pump designs which allows machined impeller passages with good surface finishes and well-controlled blade-spacing to minimize random hydraulic vibrations. It would be useful to know your operating design parameters to better understand and respond to your optimization problem.