Synthetic Jet Cooling Technology for Electronics Thermal Management—A Critical Review

TLDR: This review paper looks at different actuation methods (electromagnetic, piston cylinder, piezoelectric, etc.) to generate synthetic jet cooling and proposes an empirical correlation based on available data using non-linear regression via computational tools.

Abstract: Effective removal of excess heat from electronics equipment is the key to its intended functionality. A Defense Advanced Research Projects Agency (DARPA) hard problem is proposed in microtechnologies for the air-cooled heat exchangers (MACE) program that posed challenges to reduce the heat sink size fourfold while using only 50% of the current power budget. While numerous heat removal techniques have been proposed over the last several decades, synthetic jet actuator (SJA) is one of the leading candidates to create a game-changing cooling performance. This is due to its inherent advantages, such as size, low power consumption, ease of use, and affordability. This review article looks at different actuation methods (electromagnetic, piston cylinder, piezoelectric, and so on) to generate synthetic jet cooling. The performances of these approaches vary and need a procedure to unify the predictive capability. The performances are evaluated based on actuation (stroke length, operating frequency, and jet-to-heater spacing) and geometric parameters (shape and size of the cavity and the orifice). The flow characteristics and jet formation criterion are also discussed methods, and a critical commentary is added to normalize previous findings. Available correlations for predicting Nu numbers are evaluated and summarized through data sets for a possible unification. Finally, an empirical correlation is proposed based on available data using nonlinear regression via computational tools. To conclude, the challenges and research gaps are enumerated covering the fundamental and applied aspects of those jets for the implementation in electronics thermal management.