Thermal analysis of microchannel heat exchangers with twophase flow using FEM

Purpose To analyze twophase flow in microchannel heat exchangers used for high flux microelectronics cooling and to obtain performance parameters such as thermal resistance, pressure drop, etc. Both uniform and nonuniform microchannel base heat fluxes are considered. Designmethodologyapproach Energy balance equations are developed for twophase flow in microchannels and are solved using the finite element method FEM. A unique ten noded element is used for the channel descritization. The formulation also automatically takes care of singlephase flow in the microchannel. Findings Microchannel wall temperature distribution, thermal resistance and the pressure drop for various uniform microchannel base heat fluxes are obtained, both for single and twophase flows in the microchannel. Results are compared against data available in the literature. The wall temperature distribution for a particular case of nonuniform base heat flux is also obtained. Research limitationsimplications The analysis is done for a single microchannel and the effects of multiple or stacked channels are not considered. The analysis needs to be carried out for higher heat fluxes and the validity of the correlation needs to be ascertained through experimentation. Effects of flow maldistribution in multiple channels, etc. need to be considered. Practical implications The role of twophase flow in microchannels for high flux microelectronics cooling in reducing the thermal resistance is demonstrated. The formulation is very useful for the thermal design and management of microchannels with both single and twophase flows for either uniform or nonuniform base heat flux. Originalityvalue A simple approach to accurately determine the thermal resistance in microchannels with twophase flow, for both uniform and nonuniform base heat fluxes is the originality of the paper.