A Synthetic Jet Heat Sink with Cross-flow for Electronic Cooling

This paper presents an investigation on the operational characteristics and thermal effectiveness of a pulsed (or synthetic) jet mechanism that periodically cools at a heated surface while acting in cross-flow fluid stream. The study uses a test rig having a variable-frequency pulsed air jet impinging at a heated surface that emulates an electronic device to be cooled. The cooling characteristics of the jet are observed over a wide parametric range. The results show that the pulsed jet mechanism delivers outstanding cooling performance that is primarily dependent on the jet-impinging distance and operating frequency. Without cross flow, the pulsed jet provides about 11 K temperature reduction and 7 times more heat removal rate compared to natural convection at the heated surface. The jet impingement height indicates a strong dependency with an optimum on the heat removal rate. With cross-flow fluid stream, the pulsed jet cooling is enhanced. This combined fluid action achieves about 13 K temperature drop and delivers 2.2 times more cooling compare to pulsed jet operating alone. The pulsed jet operation is numerically simulated to understand the associated flow characteristics leading to thermal enhancement. It is recognised that the pulsed jet arrangement has the unique surface cooling ability without additional fluid circuits, making it particularly desirable for high-capacity electronic cooling applications.