Experiments and Modeling of Multilayer Copper Minichannel Heat Sinks in Single-Phase Flow

One of the most promising configurations for indirect liquid cooling of electronic systems is in the use of heat sinks or cold plates where a liquid is forced to flow through channels embedded in a solid matrix. Traditional microchannel heat sinks consist of a single layer of parallel, high-aspect ratio rectangular channels microfabricated in silicon or copper. These heat sinks can achieve very high heat fluxes due to: 1) high heat transfer coefficients from microchannels, and 2) large surface areas from high-aspect ratio channels. When manufacturing techniques prohibit the fabrication of high-aspect ratio channels, stacking or creating multilayers of single layered channels can be an alternative to increasing surface area. In this work, square channel copper minichannel heat sinks were fabricated with single and multiple layers. It was experimentally shown that multilayer heat sinks have significant advantages over single layer equivalents with reductions in thermal resistance and pressure drop. Numerical simulations using CFD were performed and comparisons were made with experimental results. An approximate one-dimensional resistance network model for both single and multilayered heat sinks was also developed. Both numerical and resistance network models compared well with experiments