Numerical Analysis of Multistack Microchannel Heat Sinks Cooled by Boiling Two Phase Flow

Microchannel heat sinks are widely regarded as being amongst the most effective heat removal techniques from the space constrained electronic devices. Boiling flow cooled MicroChannel heat sinks have several advantages such as better cooling capability due to higher heat transfer coefficients, ability to handle ultra large heat loads and low coolant inventory requirements. In the present work multi- stack microchannel heat sinks cooled by boiling two phase flow are studied to obtain improved thermal and hydraulic performances. Rectangular cross section multi-stack microchannel heat sinks (with hydraulic diameters of the order of 200 μm) cooled by boiling flow of water are analyzed using the finite element method. A unique twelve noded, repetitive finite element representing a pair of adjacent microchannels is used for the finite element modeling of the microchannel heat sinks. The analysis yields the base temperature distribution, thermal resistance and pressure drop for multi-stack as well as single stack microchannel heat sinks.