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Pubblicazioni
2019
- Comparison between cooling strategies for power electronic devices:
fractal mini-channels and arrays of impinging submerged jets
[Relazione in Atti di Convegno]
Baraldi, Niccolò; Fregni, Andrea; Sabato, Massimo; Stalio, Enrico; Brusiani, Federico; Tranchero, Maurizio; Baritaud, Thierry
abstract
Power electronic devices like Insulated Gate Bipolar Transistors (IGBTs) and diodes are often characterized by power densities and dimensions that could result in very high heat flux densities. In order to guarantee the expected performance and lifetime for these components, dedicated active cooling devices are usually adopted. In the present paper, the comparison between two different cooling strategies for power electronics is presented: fractal channel design and submerged impinging jets. Each cooling strategy is tested on two different geometrical configurations. Water is used as coolant in all cases. Assessment of the considered cooling methods is done through application of the selected configurations in a simplified system composed by a rectangular chip (heat source) separated from the coolant by a solid block. Three-dimensional conjugated heat transfer simulations are performed by using RANS solver implemented in OpenFOAM and two-equations turbulence models, resolving also the viscous sublayer. Numerical results allow to compare the cooling strategies in terms of maximum chip temperature, overall chip-to-coolant thermal resistance, and pumping power required. In summary, the fractal-channel design shows limitations in guaranteeing low chip temperatures at an affordable pumping power. The submerged impinging jets approach shows very high local
heat transfer coefficient by which it is possible to tailor the cooling expect on specific hot spots.
2019
- Numerical study of submerged impinging jets for power electronics cooling
[Articolo su rivista]
Sabato, Massimo; Fregni, Andrea; Stalio, Enrico; Brusiani, Federico; Tranchero, Maurizio; Baritaud, Thierry
abstract
Advancements in power electronic technologies require devices which are small, reliable and capable of handling large power levels. Despite efficiencies of electronic components are usually above 90%, wasted thermal powers can result in heat flux densities in the order of hundreds of W/cm2. To avoid degradation in performance and lifetime of these electronic devices, specific active cooling systems need to be adopted and submerged impinging jets represent one of the most promising solutions. In the present paper a numerical study of different cooling jet configurations is presented, and high-efficiency solutions are sought. The configurations investigated are obtained by varying nozzle diameter, aspect ratio, arrangement and number of jets. Simulations are performed on a simplified computational domain which involves a single rectangular chip (representing the heat source) separated from the coolant by a multi-material solid stack. As compared to more classical solutions like pin fins, submerged impinging jets represent an efficient technique for the cooling of power electronics. Heat is exchanged at low pumping power level. Array of jets are flexible in terms of geometry and can be specifically designed to control temperatures in critical spots.