High‐Speed Particle Image Velocimetry Measurements of Turbulent Pipe Flows for Verification of a Fluid‐Dynamic Cavitation Model

Abstract

The design of reciprocating pumps for the chemical industry requires a detailed knowledge of the apparent phenomena such as undesirable pipe pulsation and harmful cavitation. Since the detailed understanding of the entire mechanism is rather limited, emphasis will be put on the verification of a fluid-dynamic cavitation model for reciprocating positive displacement pumps. This model was established by means of particle image velocimetry (PIV) measurements carried out at a repetition rate of 2 kHz. The PIV results indicate that the fluid-dynamic cavitation model corresponds with the physical reality. While common practice dictates that cavitation should be prevented at all times, the proposed model offers a great opportunity for manufacturers to predict a limit for the extent of occurring cavitation.Cavitation is one of the main causes of damage to piping elements and hydraulic machinery. Cavitation itself is the process of nucleation in a liquid when the pressure falls below saturated vapor pressure. Due to different generation and growth mechanisms, depending on the pressure level, the classification of cavitation types is deemed to be useful. Therefore, cavita-

Particle Image Velocimetry of a Swirling Fluidized Bed at Different Blade Angles

“…For the 750 g and 1000 g bed weights, the spheroidal particles had a very short stable swirling range due to a vigorous bubbling layer. This was because the spheroidal particles were prone to be elevated more easily parallel to the bed due to their larger surface areas which resulted in higher lift forces 18, 19.…”