EFFICIENT HEAT TRANSFER BY PHASE TRANSITION IN MICROSTRUCTURED DEVICES

Devices with microchannels or similar structures with dimensions in the range of a few 100 micrometers, so-called microstructured devices, have become a powerful tool in modern process engineering for transferring huge amounts of thermal energy. The high internal surface of these devices, caused by small characteristic channel dimensions, lead to very high specific heat transfer rates. Additional increase of these high heat transfer capabilities is enabled by taking advantage of the latent heat of evaporation. During fundamental research activities phase transition and accompanying phenomena in arrays out of straight microchannels as well as novel microstructures were investigated to obtain new and additional information about these processes. A novel microstructure which is based on a new innovative design away from straight channels is able to enhance evaporation. This design, based on semicircular and semi-elliptical microstructures, leads to mixing effects as well as flow acceleration by pressure release effects including increased heat transfer properties. This novel microstructure reaches highly enhanced evaporation performance compared to linear microchannels.