Heat Transfer and Fluid Mechanics Characteristics of a 3D-printed Synthetic Jet Device using Experimental and Computational Approaches

Abstract

Thermal management in increasingly miniaturized electronic systems remains a critical challenge, as rising computing power, reduced form factors, denser interconnects, and advanced packaging techniques intensify power dissipation and junction temperature constraints. Synthetic jets (SJs), with their zero-net-mass-flux operation, compact size, and enhanced convective heat removal, offer a promising approach for localized and spot cooling without complex plumbing. This work presents a comprehensive experimental and computational study of novel 3D-printed synthetic jet devices (SJDs) aimed at guiding the design of compact, efficient cooling systems.

In the first phase, five SJD prototypes with varying cavity and orifice geometries were fabricated and characterized. Actuator deflection and jet exit velocity were measured across a broad frequency sweep to identify both structural and Helmholtz resonance behaviors. Thermal performance tests at the optimal frequencies then quantified convective heat transfer for multiple orifice-to-heater spacings. In the second phase, a refined device underwent extended assessment over a wider range of impingement distances, with hot-wire anemometry capturing detailed axial velocity profiles. Complementary three-dimensional CFD simulations elucidated the fluid-dynamic mechanisms governing heat transfer enhancement at different orifice-to-surface distances.

Key findings include: (1) shallow-cavity SJDs resonate at lower frequencies with larger deflections, while taller cavities shift resonance upward and reduce deflections; (2) peak heat transfer occurs at normalized spacings of 6-8, where coherent vortex rings maximize impingement pressure; (3) momentum flux, not velocity magnitude alone, dictates cooling performance; and (4) operating at the first (structural) resonance frequency (∼650-700 Hz) achieves nearly the same thermal benefit as the higher-frequency Helmholtz mode (∼1800 Hz) but with substantially lower power input. These results provide a rigorous framework for the future development and implementation of energy-efficient synthetic-jet cooling solutions in microelectronics.