Emerson’s team responsible for Fisher Valves & Instruments products has a great series of YouTube videos on piping cavitation and ways to mitigate the damage that it can cause. Melissa Niesen, a research engineer, uses the Marshalltown Innovation Center flow lab to provide visual and auditory demonstration of cavitation in action.

In the first 8:13 video, Cavitation Mitigation Part 1, Melissa provides an overview of cavitation and shows you the turbulent flow and associated noise level caused by cavitation—the formation of vapor cavities in liquids. She references the pressure drop at the vena contracta, which Wikipedia defines, “…the point in a fluid stream where the diameter of the stream is the least, and fluid velocity is at its maximum, such as in the case of a stream issuing out of a nozzle, (orifice).”

Melissa shares two ways to address cavitation. The first is to supply a compressible fluid downstream of where the sudden pressure drop occurs. While practical in the flow lab, this way is not as practical in most plant applications. The second way is to apply backpressure from a downstream valve to reduce the overall pressure drop.

I’ll be out the rest of the week, so I’ll queue up and schedule parts 2 and 3 over the next couple of days. In the meantime, you can connect and interact with other valve experts in the Valves track of the Emerson Exchange 365 community.