Thermal management control without overshoot using combinations of boiling liquids

Experimental results related to the use of mixtures of dielectric liquids to control temperature and overshoot while handling high heat fluxes are presented, using specially designed silicon chips containing a large polysilicon heater/resistor with nine thermal sensing diodes. A variety of pure dielectric liquids were evaluated. Data on single pure liquids show the usual expected substantial overshoot (26 degrees C average) during the incipience of nucleate boiling. The addition of a second liquid to modulate the temperature and control the overshoot has been patented. Various mixtures were tested, with some mixtures showing virtually no overshoot (0-6 degrees C) while still allowing high total heat fluxes greater than 30 W/cm/sup 2/. Conduction losses from the chip to the substrate are quantified computationally. Tests showed that the amount of overshoot has a strong sensitivity to the bulk liquid temperature. Several runs were made with each of the sample parts to check both reproducibility of the results and repeatability of the data.<
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