Design and Testing of a Bearingless Piezo Jet Micro Heatsink

Abstract

The present study utilized piezoelectric ceramics (PC) as actuators to design five new piezoelectric heatsinks and preliminarily investigated the different design types and their operating conditions, such as the frequency, placement distance, thickness between piezoelectric sheets, piezoelectric sheet size, and noise produced. The results showed that when the micro heatsink bearingless piezo jet was placed too close to the heat source, the high temperature sucked back the surrounding fluids, causing the fluid chamber temperature to rise and the cooling effect to be reduced. Therefore, the heatsink should be placed between 10 and 20 mm from the heat source. With the proper distance, the heat convection coefficient was 200% greater than that of a traditional rotary fan. The cooling effect of the five heatsinks was calculated using the thermal analysis method, and the results indicated that the convection thermal resistance of the best heatsink could be reduced by about 36%, and the frequency, flow velocity, and noise were all positively correlated. When the supplied piezoelectric frequency was 300 Hz, the noise level was similar to that of a commercial rotary fan. The tested heatsinks had one of two volumes depending on the size of the piezoelectric sheet, including 3150 mm(3) or 4050 mm(3), respectively. An array of 25-32 micro heatsinks of the same size were connected in series. The power consumption of any single heatsink was 10% of that for a rotary fan. Among the five types of heatsinks, the best type had a piezoelectric sheet diameter of 41 mm, a piezoelectric thickness of 2 mm, and an opening length of 4 mm. Furthermore, the best operating conditions were found at a frequency of 300 Hz and a placement distance of 20 mm.