Light Induced Cooling of a Heated Solid Immersed in Liquid Helium I
The study of boiling heat transfer in liquid helium has become increasingly important as more and more applications have been found and implemented. We have previously reported studies of transient heat transfer and liquid-to-vapor homogeneous nucleation in liquid helium I employing a transient superheating technique in which a single crystal of bismuth immersed in liquid helium is used as a heater-thermometer.1–3 Recently, using the bismuth crystal as well as other resistive elements as heater-thermometers, we have observed a new effect: a marked enhancement in the transient heat transfer from the heater-thermometer to the liquid helium immediately following the application of a flash of visible light.4 Our studies show that when the liquid in contact with the solid surface has been superheated to at least a certain threshold temperature, ΔTLT, the flashing of a single strobe light through the unsilvered sides of the helium glass dewar causes a sudden large drop in heater-thermometer temperature. The effect is striking: the temperature can decrease by more than 75% of the total superheat in under a millisecond.
KeywordsHeat Flux Liquid Helium Light Flash Light Effect Transient Heat Transfer
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