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takyon [soylentnews.org] writes:

+hardware

Researchers have used the recoil of bubbles [uic.edu] to mix coolant around microelectronics:

The bubbles that form on a heated surface create a tiny recoil when they leave it, like the kick from a gun firing blanks. Now researchers at the University of Illinois at Chicago, under funding from NASA, have shown how this miniscule force can be harnessed to mix liquid coolant around high-power microelectronics — in space or on Earth. [...] "In flights to Mars or the moon, equipment like computers generate a lot of heat," Yarin said. As the computers and chips become smaller and are packed tighter, the production of heat becomes a restriction on computing power.

Engineers have looked to "pool-boiling," which is liquid-cooling at a temperature near the boiling point of the fluid. In boiling, all heat is absorbed in converting the liquid to vapor, with no further rise in temperature until the phase change is complete. But the lack of gravity in space poses a special problem for pool-boiling: The bubbles have no buoyancy.

[...] Yarin and his coworkers sandwiched two heat-generating circuit chips back-to-back. By alternating the voltage to the two chips, they were able to cause the apparatus to swing back and forth through the coolant at about 1 centimeter per second. "When one chip operates, it produces bubbles and a recoil force. Then the other, and it pushes back — enough to swing the chips in the cooling fluid and shed the bubbles," Yarin said. "It works with or without gravity – in space, exactly as on Earth."

Animated GIF [uic.edu].

Swing-like pool boiling on nano-textured surfaces for microgravity applications related to cooling of high-power microelectronics [nature.com] (open, DOI: 10.1038/s41526-017-0014-z) (DX [doi.org])

Original Submission