The effects of fluid properties on cavitation in a micro domain

The cavitation of ethanol inside a 40 mu m wide micro-orifice entrenched inside a 200 mu m microchannel was experimentally studied. Experiments were conducted at inlet pressures ranging from 60 Psi to 100 Psi and cavitation numbers from similar to 0.1 to 1. Flow patterns along the axial position downstream from the orifice at various cavitation numbers were visualized and mapped. Cavitation inception and choking indices are reported and compared to the corresponding values of water in a similar configuration. In contrast with water cavitation, the presence of a bubbly flow pattern in the immediate vicinity of the orifice was very notable. The cavitation inception values were higher than those for water, but much lower than the values reported for large-scale orifices. Unlike for water, choking cavitation was observed only after significant reduction in the cavitation number past the inception value.