Now, thanks in large part to software tools, pump engineers as well as engineering students can see phenomena they only "heard" about before. The PumpLab™, a cabinet-size unit on casters, offers a see-through view into fluid circuits powered by a centrifugal flow pump.
Perry Kuznar, PE with the developer Turbine Technologies Ltd., says as a mechanical engineer he studied flow events such as cavitation, and even heard it when it happened in pumps. "But I never fully appreciated what was happening until I was able to see it within the demonstrator," he notes.
A centrifugal flow pump with changeable impellers (straight blades, backward inclined blades, and forward swept blades) powers the see-through flow circuit. The entire flow path from reservoir pick-up to return is visible. Driving the pump is a 3-hp Baldor Electric high efficiency ac motor with a vector drive for variable speed control and accurate torque and rpm measurement.
Key to lab utility, and further enhancing its use as a teaching tool, is onboard incorporation of National Instruments LabVIEW (www.ni.com) data acquisition software. NI also supplies the data acquisition cards in the lab and its computer. This system monitors seven sensor outputs: pump inlet pressure, inlet temperature, exit pressure and temperature, flow rate, and drive torque and rpm. Captured digital data can be stored or replayed for analysis, or analyzed off site in common formats such as NotePad, Excel, or Word.
PumpLab-derived data can be used to: Analyze pump characteristics at various speeds; develop performance maps (including surge-line determination); observe cavitation with accompanying electronic verification and data capture; record flow rates with a rotameter; determine pump power required, efficiency, and volume vs. pressure relations; and test custom designed impellers.
Company President and PumpLab designer Wolfgang Kutrieb says the greatest challenge in bringing about the lab, or any project, is to "Keep in mind what this is going to accomplish. We wanted to inspire students and make them enthusiastic in the education process." He decided that literally providing a clear view of an entire pump system was key. "We couldn't just buy a pump and put in a window. We needed to design a clear pump from the bottom up with flat surfaces on the outside for an undistorted view within."
Materials for the pump and each portion of the flow circuit were selected for maintaining clarity after they were fabricated into the lab unit. Where polishing was not needed, clear polycarbonate was used. If clarity after polishing was needed, then acrylic was chosen. Tubing is clear PVC. And finally, Kutrieb adds that everything had to come together at a reasonable cost.
Kuznar notes that when designing the PumpLab, as well as the company's Rankine Cycler™, a tabletop steam powerplant simulator, engineers used SolidWorks CAD tools. Specifically to PumpLab, Kuznar says, "We developed the solid models, which were turned over to a CAD shop to develop the drawings. These were sent to multiple vendors for manufactured and purchased parts. All multiple-vendor parts went together beautifully in assembly on the first try. We were able to skip the prototype stage and deliver both as production quality offerings."