Spray cooling high power dissipation Applications (SANGRIA): From fundamentals to Design

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Engineering


The advancement of numerous technologies has become increasingly reliant on the ability to dissipate large quantities of heat from small areas. Current designs in power electronics, supercomputers, lasers, X-ray medical devices, nuclear fusion reactor blankets, spacecraft, and hybrid vehicle electronics, and future improvements, rely on record high heat transfer rates. This rapid increase in heat dissipation rates required by such devices has led to a transition from more traditional fan-cooled heat-sink attachments to liquid cooling techniques.

Liquid cooling techniques operating in single-phase, however, have now reached their limit being forced to run at very low inlet temperatures and exceedingly high mass flow rates, resulting in unacceptably high pressure drops and surface temperature gradients. Innovative approaches are urgently needed to overcome these significant shortcomings: one such approach is spray-cooling.

Spray-cooling uses a nozzle to break up the liquid coolant into fine droplets that impinge individually on a heated surface. 'Low'- and 'high-temperature' spray-cooling applications involve surface temperatures below and above the critical heat flux (CHF), respectively. Single-phase spray-cooling (relies on liquid sensible heat rise only) provides greater operational stability and spatially uniform heat removal than liquid cooling, reducing the likelihood of large surface thermal gradients, particularly important for fragile electronic components. Two-phase spray-cooling (relies on liquid sensible heat rise and latent heat), are superior to single-phase systems and furthermore, compared to pool/flow boiling alternative systems, offer far less resistance to vapour removal from a heated surface enabling superior drop-surface contact . In fact, the CHF increases from 1.2 MW/m2 (for water pool boiling) to 10 MW/m2 for water sprays in two-phase applications.

SANGRIA is an ambitious 3-year collaborative research programme aimed at investigating the fundamental mechanisms and transfer processes underlying spray-cooling. This project combines cutting-edge experimental techniques that furnish spatiotemporally-resolved diagnostics of the thermal, interfacial, and hydrodynamic fields, with multi-scale theory, modelling and 3-D high-fidelity numerical simulation that bridge the molecular and continuum-scales. The deep insights generated from SANGRIA will be harnessed to provide tools that are practically implementable by our industrial partners in order to maximise impact.

Industrial and academic partners will provide additional technical support and feedback during the research programme plus pathways for direct industrial impact. The industrial partners include possible users of this technology: TMD Ltd (manufacturers of electronic equipment, high heat flux devices); Oxford naNosystems (manufacturers of enhanced heat transfer surfaces); ANSYS (Software development); Siemens (Software development); Spraying Systems Co. (Nozzle manufacturers); Syngenta (users of nozzles). LaVision offered a 15% discount on their Particle Master System. The academic partners from the University of Nottingham, Sorbonne University, Technical University of Darmstadt and Kyushu University are internationally recognised experts in single and two-phase thermal systems, including spray cooling. Participation and presentations during the HEXAG and PIN meetings will facilitate feedback and technology transfer.


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