Integration of Two-Phase Flow Boiling in Future Power Packages

Flow boiling heat transfer is a topic that is of interest for the cooling of power electronics, high-performance computing in automotive applications, and other electronic packages with particularly high heat flux. Based on the investigations from [Schacht 2024], in which the effects on the high performance computing (HTC) with regard to the wetting behavior of de-ionised water (DI water) on silicon (SI) and gold (Au) surfaces during two-phase flow boiling were investigated, an initial design for the integration of two-phase cooling together with the power electronics in one housing (e.g. HPC or automotive) was introduced and the requirements for a controlled two-phase cooling system were discussed. In this paper, the use of a Glycol-DI water mixture instead of DI water as a coolant is experimentally investigated with regard to heat transfer performance. In addition, the influence of the surface properties of matte and polished silicon on the heat transfer coefficient performance is investigated. Glycol-DI-water mixture is used as a coolant in applications where ambient temperatures can be below 0°C (e.g. in the automotive industry) and which has no negative impact on global warming and is explosion-proof in useWith Glycol-DI-water mixture as coolant a maximum heat transfer coefficient HTC ~ 4.4 kW/(m2K) at a volume flow rate of $v$ = 0.5 l/min (Tin = 60°C) with a maximum wall heat flux of $q_{wall}$ ~ 38 W/cm²and a wall temperature of Twall ~ 165°C could be achieved. An influence between matte and polished silicon surfaces on the heat transfer could not be determined.