A model based on analytical spreading relations for predicting the thermal performance of vapour chambers in thermal management solutions

Abstract

Vapour chambers are two-phase heat transfer devices that are typically used for thermal spreading applications in electronic devices with high heat fluxes. In this work, a novel method for predicting thermal resistance of a vapour chamber was developed and integrated within the complete model for a thermal management system. The vapour chamber model combined three sub-models; the spreading sub-model (1) and one-dimensional sub-model (2) to estimate thermal resistances within the evaporator and condenser regions, respectively, and the effective thickness sub-model (3) to estimate the effective fluid distribution within the wick structures. Spreading mechanisms within the evaporator region were included via the analytical solution for thermal spreading. Model results were compared to experimental results for thermal resistance and showed acceptable agreement with the vapour chamber model. The vapour chamber thermal resistance contributed up to 40% of the systems total thermal resistance, which highlighted the need for a vapour chamber model. This model was further explored to provide insights into the heat transfer mechanisms within the vapour chamber. It was found that the spreading sub-model (evaporator region) contributed up to 90% of the vapour chambers thermal resistance. Its contribution decreased as heat load increased mainly due to the reduction in the effective thickness of the fluid layer in the evaporator wick. The one-dimensional sub-model (condenser region) was more significant at higher heat inputs, contributing up to 28% of the vapour chambers thermal resistance. The model could determine the thermal resistance of the vapour chamber based on its dimensions, materials and operating conditions. This could be useful for thermal engineers investigating the application of vapour chamber heat spreaders that require rapid and accurate predictions for vapour chamber performance.