Professor Ari Glezer has developed a synthetic air jet that may replace the traditional cooling fan.
Present Position: Professor of Mechanical Engineering, GeorgiaTech
Degrees: B.S. in Mechanical Engineering, Tel Aviv University, Israel; M.S. and Ph.D. in Aeronautics, CalTech
Area of research: Thermal management of electronic systems, including the use of synthetic air jets that blow turbulent air puffs for efficient cooling
How it works: A synthetic jet is formed by a miniature module that has a moving diaphragm built into a cavity with an orifice. When the diaphragm is pushed toward the orifice, the expelled air from the cavity forms a turbulent "puff" pushed away from the orifice. When the diaphragm moves away from the orifice, make-up air is drawn back into the cavity through the same orifice. If repeated continuously, one can essentially create a jet that is synthesized from the ambient air. The process is similar, in principle, to breathing.
What's unique about it? The synthetic jets work without blowers. The jet fluid uses only ambient air in the vicinity of the jet to remove heat from hot surfaces and also to mix the heated air with the ambient air stream.
How do the jets compare to cooling fans? Cooling fans tend to be hindered by power consumption, noise, and reliability, as well as space and form constraints, unlike synthetic jets. Also, fans have a bottleneck (thermal resistance) in the heat flow from a thin layer of air preventing heat transport. Synthetic jets reduce this bottleneck by improving the heat transfer coefficient by almost two times, resulting in up to 30 percent improvement in heat removed.
Biggest challenge: Providing engineers with the design computational tools to integrate them into existing and new hardware.
Target applications: The SynJets—now at the prototype stage—may eventually be integrated into heat sinks, or used to cool electronic hardware.
For info on a NASA-sponsored CFD workshop on synthetic jets, go tohttp://cfdval2004.larc.nasa.gov. Contact Glezer atari.glezer@me.gatech.edu.
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