The Technology

About SynJet® Cooling Technology

The SynJet® module creates turbulent, pulsated air-jets that can be directed precisely to locations where thermal management is needed. From LED heat dissipation to computer cooling, SynJet technology is helping designers solve cooling challenges requiring high reliability and flexible form-factor implementations.

How a SynJet® Works.

The basics of a SynJet® are described below. To get more detail continue reading this page or watch or interact with the SynJet flash demos.

SynJet Cooling Technology Basic Operation

1. An oscillating diaphragm creates pulses of high velocity turbulent air flow.
2. The high velocity flow “entrains” or pulls air in its wake increasing overall air flow by as much as 5 times.
3. The turbulent air flow improves the heat transfer out of the heat sink, while the entrained air sweeps the hot air out of the system, thus cooling more efficiently.

How a SynJet® Works – In Detail.

The vortex-dominated SynJet flow enhances small-scale mixing near the heated surfaces to yield higher effective heat transfer at low-volume flow rates compared to conventional air movers. The SynJet flow is created using our patented actuator technology and proprietary fluidic packaging expertise.

The system wide heat removal takes advantage of the ejector effect inherent to high-momentum jet flows. As it operates, the SynJet module expels high momentum pulses of air. Each pulse of air “entrains” or pulls nearby ambient air behind it in its wake. The diagram below shows the velocity vectors of the SynJet flow as the jet is ejected.

5 frame graphic of the Time History of a SynJet Pulse technology alternative to a high reliability fan for industrial spot cooling.

Watch the pulse in real time in this video.

Figure 1a shows the pulse of air emerging from the nozzle. In Figure 1b the pulse has moved away from the nozzle. Note the large velocity vectors associated with the vortices accompanying the SynJet formation. In Figure 1c the pulse has moved further away, and the entrained air can be seen behind it in the form of the large velocity vectors all pointing in the direction of the pulse. In Figure 1d the tail of the pulse is seen. Finally in Figure 1e the pulse has almost fully left the frame, and the air can be seen recharging the nozzle in preparation for the next pulse.

The result is highly turbulent, high heat transfer coefficient air flows located directly where they are needed inside a product providing system level heat removal.

Key Benefits:

Increased thermal efficiency

Several intrinsic qualities of SynJet modules result in much more thermally efficient air flow than that created with conventional air movers. The turbulence of the flow results in more efficient heat transfer from the heat source to the air. The pulsating nature of a SynJet airflow increases mixing between the boundary layer and mean flow. Finally, the self-induced entrained flow results in the ability to move the heated air out of the system. SynJet modules can be tailored to the air flow needs of any system. Multiple hot spots can be cooled without heatsinks as a SynJet module places the cooling directly where it is needed without complicated ducting. Heat sinks can be cooled much more effectively by providing uniform flow across the entire heat sink. The hub of a fan can often create problems and dead spots within a chassis, but SynJet flow spans the entire heat sink and cool all channels equally. By the same count, the SynJet modules may be tailored to direct more flow across the center of the heat sink where the heat source is located. Heat sink flow bypass becomes a thing of the past as well – the low pressure created by a SynJet module at the heat sink inlet actually causes more air to be drawn through the flow channels for a given energy input.

All in all, this means it is possible to remove more heat with less air.

High Reliability Cooling

With the elimination of frictional parts common to fans and blowers, the potential failure modes are greatly reduced, the need to evaluate forced air vs. natural convection is eliminated, and the MTBF (Mean-Time-Between-Failures) of even the most reliable fan is exceeded. For applications that operate in extreme environments, the device can be constructed out of robust materials. For applications previously requiring natural convection due to failure intolerance factors, the forced air vs. convection tradeoffs no longer apply.

With SynJet modules, the air mover will no longer be the lowest reliability component in the system, as is the case with conventional air movers.

Low audible noise

As described earlier, SynJet modules produce airflow that is much more thermally efficient, therefore the amount of air flow needed to cool the same heat load is reduced. Lower flow rates translate directly to lower acoustic emissions. In addition, by not having any bearings, brushes, or other frictional parts, the SynJet module eliminates the acoustic problems associated with these interfaces. Acousticians know that there is more to sound than just the SPL measurement. SynJet flow can often be tailored to accommodate psychoacoustic perceptions as well.

Depending on the application, SynJet modules may be designed for effectively silent operation.

Low power consumption

Through the development of very efficient actuators, SynJet modules require very low power to operate.

SynJet modules can cool the same thermal load as a conventional fan with a fraction of the power needed.