A photographic measurement technique was developed to quantify the vapor volume flow rate departing from a wire during boiling. The vapor flow rate is determined by measuring the volume of bubbles after departure from the boiling surface in consecutive frames of high-speed video. The measurement technique is accurate and easy to implement. The volumetric flow rate data are used to calculate the latent heat transfer and, indirectly, sensible heat transfer which comprise the nucleate boiling heat flux. Electronics Cooling with Forced Convective Boiling Early computer systems have used air-cooling to dissipate the heat generated by electronic components.
Personal computers are currently air-cooled by either free or forced convection.
Direct immersion cooling with a dielectric fluid has thus become a forerunner in this emerging technology area because of the high heat transfer coefficients made possible by the intimate contact between the device and the coolant. Because forced convective boiling offers great increases in the heat transfer coefficients, current research focuses on flow boiling of a dielectric fluid on discrete heat sources which simulate electronic chips. Experiments are being performed to understand the effects of velocity and subcooling on microporous-enhanced surfaces in convective boiling. Additionally, the microporous-coated heater shows a remarkable insensitivity to velocity and subcooling effects indicating that boiling is dominating the heat transfer removal. Enhanced Small-Channel Convective Boiling Convective boiling in compact heat exchangers and cold plates has become attractive in recent years because of many benefits including higher heat flux capability, nearly uniform temperature operation, and lower working fluid flow rates.