A Low-Cost Method for Characterizing the Inception and Extent of Cavitation in High-Pressure Homogenizers

Abstract

High-pressure homogenizers are prone to cavitation, which causes wear and influences breakup efficiency. However, the inception point, as well as the extent and intensity, depends on geometry, operation, and fluid properties. While several methods have been previously suggested to characterize cavitation in homogenizer valves (including ultrasonic methods), they have required highly specialized, sensitive, and costly equipment. Consequently, these methods have not been widely adopted. This contribution demonstrates how a low-cost (∼$100) handy recorder, combined with simple audio processing (software provided), can be used to rapidly measure cavitation inception and extent in a high-pressure homogenizer. For the laboratory-scale homogenizer used to exemplify the method, cavitation inception occurs at a cavitation number of 0.15. From an applied perspective, this approach shows how the operator can easily choose between running the homogenizer with or without cavitation by adjusting the backpressure (i.e., having no backpressure results in cavitation regardless of homogenizing pressure, while a 5 MPa backpressure suppresses cavitation regardless of homogenizing pressure).