Heat Transfer Performance of a Synthetic Jet at Various Driving Frequencies and Diaphragm Amplitude

Abstract

The miniaturization of electronic devices with high-speed processing components is aggravating the heat generation of devices/systems. Space constraint has become a major issue in electronic cooling as these system can no longer accommodate a fan and liquid piping. Synthetic jets are an alternative solution because of their low operating cost and low space requirement. In this work, we fabricated a synthetic jet and analyzed its amplitude motion at different frequencies to measure the enhancement of heat transfer. ANSYS FLUENT $$^{{\textregistered }}$$ 15 was used to identify the vortex formation related to the fluid velocity profile during the ejection and suction phases to substantiate heat transfer performance. The amplitude was determined by conducting laser Doppler experiments for each frequency applied. The experimental results were validated against numerical prediction using an appropriate turbulent model and a structured meshing grade. The conformity between the numerical and experimental results was found to be < 5%. The maximum velocity was observed at 500 Hz driving frequency, which agreed with the result that the resonance frequency at 500 Hz had the highest amplitude and sweep volume. A large vortex formation was also recorded during the ejection phase at 500 Hz, resulting in the maximum temperature drop and a higher heat transfer coefficient (h) than the nonresonance frequency. The synthetic jet operating at the resonance frequency produced the maximum amplitude, fluid velocity, and large vortex formation proportional to h.