GOALI: Pulsed sprays for cooling high power devices

The University Of Central Florida Board Of Trustees, Orlando FL

Investigators

Abstract

The increasing demand for faster and more powerful devices is a ubiquitous trend in science and technology. From high-speed transportation to personal devices to data centers, efficient, cheap thermal management is currently one of the key bottlenecks for advancing the technical envelope. Spray cooling, particularly with boiling-based cooling processes, is expected to play a growing role in the development of new 3D microelectronics, electro-optic devices, and manufacturing processes such as rapid 3D printing. Currently, most devices and large-scale data centers are cooled by a combination of air fans and water cooling channels. However, to meet the heat dissipation demands for the next generation of more powerful and more compact devices and data centers, liquid cooling with the added benefit of phase-change cooling (e.g., boiling and evaporation) is needed. This work pursues the use of pulsed sprays to better understand the fundamental limits of cooling high-power devices with boiling and evaporating fluids. Also, this work will facilitate the collection of systematic fluid flow-field and thermal transport data – both of paramount importance for predicting and understanding phase-change cooling instabilities. The research aims to fully understand the critical heat flux and Leidenfrost effects during pulsed spray cooling. The project has three major research and educational thrusts: (1) Establish refined spray cooling capabilities with moderate area, hemiwicking-textured surfaces/devices and advanced optical metrologies for systematic characterization of spatiotemporal temperature and flow-fields. (2) Understand the thin-film thickness and the instantaneous and time-averaged heat transfer characteristics on structured surfaces with temperatures up to and beyond the Leidenfrost point. (3) Study control allocation methodologies for pulsed, spray/jet cooling with multiple spray nozzles. The application of optimized hemiwicking-structured surfaces adds a transformative niche to this research. Such structures will not only ‘extend’ the liquid-to-solid wetting beyond its intrinsic wetting length in variable gravity environments, but can also reduce droplet splashing, rebound, and entrainment – via using sharp tipped, half-conical (anisotropic) pillars. The project supports many hands-on, educational, and industrial outreach components, facilitating broader impacts from K-12 activities to undergraduate senior design projects to distinctive research for doctoral degrees. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.