Experimental investigation of a confined flat two-phase thermosyphon for electronics cooling

• Published in: Experimental thermal and fluid science Vol. 96; pp. 516 - 529
• Main Authors: Narcy, Marine, Lips, Stéphane, Sartre, Valérie
• Format: Journal Article
• Language: English
• Published: Philadelphia Elsevier Inc 01.09.2018; Elsevier Science Ltd; Elsevier
• Subjects: Boiling; Confined boiling; Cooling; Electronics; Evaporation; Experiments; Heat pipe; Heat pipes; Heat sources; Heat transfer; Inclination; Mechanics; Multiphase flow; Physics; Thermal resistance; Thermics; Thermodynamic properties; Thermosyphon; Thermosyphons; Two phase flow; Two-phase heat spreader; Thermosyphon; Heat pipe; Confined boiling; Two-phase heat spreader; thermosyphon; confined boiling; two-phase heat spreader; heat pipe
• ISSN: 0894-1777; 1879-2286
• DOI: 10.1016/j.expthermflusci.2018.01.018

•A confined flat two-phase thermosyphon was designed and characterized.•Various flow regimes were visualized.•Evaporation and condensation heat transfer coefficient were compared to correlations.•The confinement enables to increase the degree of freedom of the heat sources location.•The system has a very low sensitivity to changes of the inclination angle. A novel type of two-phase heat spreader based on a flat confined thermosyphon is proposed for electronics cooling applications. Two wickless flat copper-water heat pipes with an inner thickness of 3 mm were experimentally investigated for two-phase flow visualizations and characterization of thermal performance. The effects of heat input, filling ratio, inclination, and saturation temperature were studied. Experimental results show that the confinement of the fluid inside the heat spreader induces confined boiling phenomenon with a strong coupling between condensation and boiling mechanisms. They also highlight an enhancement of heat transfer and interesting performance such as high heat transfer capability (tested up to 10 W/cm2 with a corresponding thermal resistance around 0.07 K/W at an optimum filling ratio), low sensitivity to inclination and higher degree of freedom on heat sources location compared to a classical thermosyphon.