Cavitation in Negative-pressure Microcapillary Devices with Tapered Constrictions: Experiment and Numerical Simulation

摘要

Microcapillary devices with tapered constrictions were fabricated for the study of the features of the cavitation. The cavitation was induced by applying negative pressure at the outlet with opening the inlet to atmospheric pressure, and the experimental results show that the cavitation bubbles generated at the center of the tapered tip flow upstream and adhere on the wall near the orifice, which is explained by the recirculation flow according to the numerical simulation results. The desinent cavitation number keeps constant for a microcapillary device, and the device works in a negative-pressure system is more susceptible to the cavitation than that works in a positive-pressure system. In addition, the effect of the orifice size on the incipient cavitation number and the desinent cavitation number has been studied with five devices with different sizes of the orifices from 50 to 120 microns. Both the incipient and desinent cavitation numbers increase monotonely with the size of the orifice. These results may be helpful to the design of the geometries of the microfluidic devices for various applications.