Figure 1 – Meridional Section
Figure 2 – Blade Design
Figure 3 – Full 3D CAD Output
SPP Pumps – www.spppumps.com
SPP Pumps share some of the success they have seen with centrifugal pump design through the use of CFturbo provided by 80/20 Engineering.
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For more than 130 years SPP Pumps has been a leading manufacturer of centrifugal pumps and associated systems, a global principal in design, supply and servicing of pumps, pump packages and equipment for a wide range of applications and industry sectors.
SPP pumps and systems are installed in all continents providing valuable high integrity services for diverse industries, such as oil and gas production, water and wastewater treatment, power generation, construction, mines and for large industrial plants.
Major SPP Pumps Applications
Major applications include water treatment & supply, sewage & wastewater treatment, fire protection, and mobile pumps for rental sectors, for which their low life cycle cost and environmental considerations are fundamental design priorities.
During 2014, SPP Pumps carried out an evaluation of turbo-machinery design tools that could assist their development process and selected CFturbo for this purpose.
Below is a brief summary of the some of the initial work along with representative images opposite.
Within the initial project scope, the casing geometry was to be retained, which imposed restrictions on the shape of meridional cross section. This makes any allowable changes almost negligible and therefore it was decided to keep the original meridional cross section unchanged.
However, the meridional shape was re-modelled in CFturbo (see figure 1). The leading edge at the hub has been positioned a little further from the suction for better efficiency.
The main dimensions remained as per the original design: suction diameter D1=69.5mm, outlet diameter D2=139mm and outlet width B2=10mm.
Potential flow calculations were performed to acquire an estimate for the velocity distribution in the meridional cross section (figure 2).
From there, the leading-edge blade angles were determined, which are summarized in the below:
in,hub [deg] 21
in,shroud [deg] 19
out [deg] 28
To obtain suitable blade angle progression, a wrap angle of 130 degree was chosen with 4 degree sweep at the trailing edge.
The resulting 6 blade impellers are compared in figure 3.