Piezoelectric-based Liquid Synthetic Jet Generator: An Ultra Low-energy Solution for High Flux Heat Management

Background

The increasing demand for faster and more efficient microprocessors in data centers has led to significant thermal management challenges. As microprocessors become more powerful, they generate more heat, which traditional air cooling systems struggle to dissipate effectively. This has prompted a shift towards liquid cooling solutions, which offer superior heat transfer capabilities. However, existing liquid cooling techniques, such as indirect water cooling with rear door heat exchangers and direct liquid cooling using water blocks, often involve complex systems with multiple components, limiting their scalability and efficiency. Moreover, immersion cooling, while effective, requires innovative methods to enhance heat transfer further. Current synthetic jet devices used in liquid cooling systems tend to be bulky and require high-pressure sources, making them less suitable for compact and efficient cooling solutions. The challenge lies in developing a more portable, efficient, and compact system that can effectively manage the thermal output of high-density electronics without compromising on performance or reliability.

Technology Overview

This invention is a compact piezoelectric-driven vortex-jet generating device designed to produce liquid jets without the need for traditional high-pressure sources and multiple components. The device integrates all necessary components into a unit measuring 4×41×41 mm³ and operates on the principles of synthetic jet devices (SJDs). It uses an oscillating diaphragm to create pulsating pressure variations, which form vortex rings that enhance momentum transfer and sustain a quasi-steady jet. The actuation is achieved through a piezoelectric composite diaphragm made of brass and PZT-5A/5H ceramics, driven at 120 to 180 V peak-to-peak voltage, with projection to reduce below 40 V peak‑to‑peak by adapting single crystal piezo ceramics. A custom manufacturing process ensures a pinned boundary condition for maximum deflection and reliability. The device’s body, including the orifice and cavity, is 3D printed, and the diaphragm is attached with a high-strength acrylic adhesive. The conical cavity design minimizes fluid volume while enhancing vortex generation, improving cooling performance. Silicone insulation is used to prevent current leaks, ensuring safe operation in conductive liquids without significantly affecting the diaphragm’s resonance frequency. This design offers a significant advancement in liquid cooling technology, particularly for electronics, by enhancing heat transfer capabilities while reducing complexity and energy consumption.

Further Details:

• M. Azarifar, M. Arik, Liquid synthetic jets for high flux electronics cooling, Applied Thermal Engineering 261 (2025) 125007, pp. 1–8

Stage of Development

The device has been validated in a laboratory environment and is at Technology Readiness Level (TRL) 3 to 4.

Benefits

1. Compact Design: The piezoelectric-driven vortex-jet generating device is significantly smaller (4×41×41 mm³) compared to traditional liquid cooling systems, which often require bulky actuators and large cavities. This compactness enhances portability and integration into confined spaces.
2. Efficient Actuation: The use of a piezoelectric composite diaphragm, made of brass and PZT-5A/5H ceramics, allows for efficient actuation with significant deflection and resonance, unlike traditional systems that rely on high-pressure sources.
3. Enhanced Cooling Performance: The conical cavity design of the device reduces fluid volume and enhances vortex generation.
4. Energy Efficiency: By utilizing synthetic jet devices (SJDs) that generate pulsating pressure variations, the device achieves enhanced heat transfer capabilities with reduced energy consumption compared to traditional liquid cooling systems.
5. Safety in Conductive Liquids: The device’s silicone insulation prevents current leaks, ensuring safe operation even in conductive liquids.
6. Custom Manufacturing Process: The custom manufacturing process ensures a pinned boundary condition for maximum deflection and reliability.
7. 3D Printing Optimization: The body of the device, including the orifice and cavity, is 3D printed, allowing for further optimization and customization.
8. Integration with Immersion Cooling Systems: The device can be integrated into immersion cooling systems, generating a cross flow that enhances heat transfer, which is an improvement over existing systems that may rely solely on primary immersion flows.
9. Optimized Heat Transfer: The device has demonstrated outstanding heat transfer performance with a coefficient of up to 1.5 to 2 W/cm2·K achieved using minimal power consumption (< 0.2 W).

Applications

1. Data Center Cooling: The piezoelectric-driven vortex-jet generating device is highly advantageous for cooling electronic computing components in data centers by enhancing heat transfer efficiency through synthetic jet-induced liquid flow.
2. High-Density Electronics Cooling: The compact and efficient design of the device makes it ideal for cooling high-density electronics systems, where traditional air cooling methods are insufficient.

Opportunity

The research team is seeking a development partner to collaborate on scaling up the manufacturing process, integrating the LSJ into heat sinks, cold plates, commercial systems, and conducting further testing under real-world conditions. The team will continue to support the development by sharing insights, refining the design, and ensuring successful implementation.

The researchers can provide:

• Detailed design documentation and experimental data.
• Prototype units for evaluation and testing.
• Expertise in optimizing and adapting the technology to specific applications.