Intrusive temperature measurement of the cavitation bubble collapse using cold wire

Cavitation is a phenomenon of rupturing the liquid when the liquid is subjected to a decrease in pressure at roughly constant temperature. Cavitation is the fundamental reason for the material erosion when the bubbles are collapsing closer to the surface. These bubbles also produce a very high temperature (thousands of degrees celsius) for a very short time (order of nano- or micro-seconds) during the collapse. Many theoretical analysis have predicted that the bubbles can raise upto few thousands of degrees celsius, and some non-invasive experimental studies using spectroscopy have shown that as well. But, to the best of our knowledge no intrusive measurement has been done to charecterize the temperature profile during the cavitation spherical bubble collapse. We have designed a cold wire sensor of the thickness of ~15 to 50 micrometers with the sensing region of 2 millimeter. These cold wires are made with kevlar or nylon fibers, titanium, nickel, silver, and silicon dioxide. The single bubble is allowed to collapse on the sensing region of the sensor, and the change in resistance is correonded to the temperature uisng the mathematical function that is callibrated prior to the experiment. The preliminary results have shown that the bubbles do raise to few thousands of degrees celsius.