Bubbles That Beat The Heat
LIQUID THAT BUBBLES AT A rolling boil may not look refreshing. But someday, those bubbles could be harnessed to cool off hot X-ray devices, fusion-reactor components, and even rocket nozzles. With support from 3M and the Navy, Purdue University mechanical engineering professor Issam Mudawar created a box-like device that dissipates heat by forcing liquid through tiny channels the size of hypodermic needles. Attached to any hot surface, the box absorbs heat, transfers it to bubbles that form on the channel walls (shown on TV above), and flushes it away. Mudawar has already tested his devices as heat sinks for semiconductor chips, and he's studying military applications.