Modeling and Design Optimization of Ultrathin Vapor Chambers for High Heat Flux Applications

Abstract

C E Ergun's coefficient, 0.55.

Recent Advances in Vapor Chamber Transport Characterization for High-Heat-Flux Applications

“…The potential for complete numerical modeling of boiling heat transfer is supported by good agreement with data obtained from surfaces with single or multiple controlled nucleation sites [163,172]; however, further computational advancements are required to predict nucleate boiling in complex three-dimensional geometries, particularly at high heat fluxes when vapor-liquid interfaces evolve rapidly. To obtain reasonable comparison against experimental vapor chamber performance data for conditions that result in boiling in the wick structure, Ranjan et al [173] adopted a semi-empirical approach to model boiling conditions at high heat flux inputs. The foundational numerical model was adapted from [160], as described in Section 3.3.1.…”

“…This correlation was further explored by Ranjan et al [173] using the numerical vapor chamber model as described in Section 3.3.2, which was calibrated to the RFTGP experimental test data from [81]. The numerical model was used to explore the design of a 1 mm overall thickness vapor chamber device.…”

“…It was observed that the thermal resistance of the vapor core (due to the saturation pressure/temperature gradient) becomes increasingly important at reduced thicknesses. Thereby, water vapor thermophysical property variations lead to non-linear device thermal resistance behavior with linearly varying input heat flux and external condenser temperatures [173]. A parametric variation of the relative wick and vapor core thicknesses concluded that the minimum wick thickness should be selected such that a capillary limit is not reached at the desired operating heat flux in order to reduce the evaporator and vapor core thermal resistances.…”

Patterning the condenser-side wick in ultra-thin vapor chamber heat spreaders to improve skin temperature uniformity of mobile devices

“…The numerical modeling methodology used in the current work is adapted from Vadakkan et al [15] and was previously validated against experimental data by Ranjan et al [16]. The model solves the governing continuity and momentum equations in the wick and vapor core, and the energy equation in the wall, wick, and vapor core of the vapor chamber.…”

A validated time-stepping analytical model for 3D transient vapor chamber transport

“…Such models are only limited by assumptions inherent in the governing equations used to represent the transport mechanisms. Vadakkan et al [4] and Ranjan et al [5,6] developed a finite-volume-based numerical model to solve the mass, momentum, and energy transport equations in the wall, wick, and vapor core of the vapor chamber, coupled with phase change at the wick-vapor interfaces. A model solving the same governing equations using the finite-volume method was developed by Famouri et al [7] using cylindrical coordinates to model the behavior of heat pipes.…”