Effect of the Working Fluid Charge Ratio and Heat Flux on the Temperature Homogenization Characteristics of a Vapor Chamber-Type Heat Spreader

• Published in: International journal of thermophysics 2022-11, Vol.43 (11), Article 168
• Main Authors: Han, Jonghak, Bae, Hyuncheol, Joung, Wukchul
• Format: Article
• Language: English
• Subjects: Chambers; Classical Mechanics; Condensed Matter Physics; Geophysics; Heat conductivity; Heat flux; Heat sinks; Heat transfer; Heat transmission; High temperature; Homogeneity; Homogenization; Industrial Chemistry/Chemical Engineering; Physical Chemistry; Physics; Physics and Astronomy; Spreaders; Thermal conductivity; Thermodynamics; Vapors; Working fluids
• ISSN: 0195-928X; 1572-9567
• DOI: 10.1007/s10765-022-03088-9

In this work, the temperature homogenization characteristics of a vapor chamber-type heat spreader were investigated. A copper vapor chamber with dimensions of 102 mm × 102 mm × 5 mm (width × length × thickness) was tested, and the distributions of the radial temperature and cumulative effective thermal conductivity across the heat spreading surface were measured at different working fluid charge ratios and heat fluxes. Water was employed as the working fluid at charge ratios of approximately 30%, 40%, and 60%. The vapor chamber was heated at the center within a heat flux range from 100 W·cm −2 to 200 W·cm −2 with a heat sink located at the peripheral edge to induce one-dimensional radial outward heat flow. Based on the obtained results, it was found that the temperature homogenization characteristics of the vapor chamber were significantly influenced by the working fluid charge ratio combined with the applied heat flux and heat sink temperature uniformity. Thus, to improve temperature homogeneity, the vapor chamber should be operated with a proper amount of the working fluid at a high heat flux (lower than the critical value causing drying) together with a heat sink of a high-temperature uniformity. Regarding the tested vapor chamber operated at a 30% working fluid charge ratio, which produced the lowest level of temperature asymmetry, the overall effective thermal conductivity ranged from 2460 W·m −1 ·K −1  ± 240 W·m −1 ·K −1 to 2910 W·m −1 ·K −1  ± 290 W·m −1 ·K −1 at 180 W·cm −2 .