Transient thermal characteristics of silicon microchannel flow boiling

Abstract

Microchannel flow boiling with excellent heat dissipation capability is widely applied to thermal management of various high-power density thermal systems. Previously, microchannel flow boiling has been thoroughly studied under constant heat loads. However, in practical applications, the thermal components usually suffer from dynamic input power, resulting in significant fluctuation of working temperature. Hence, the research of transient behaviors of flow boiling is very important, particularly for dynamic heat loads. In this study, systematic experiments were carried out to understand transient thermal responses of microchannel configuration with auxiliary channels and multiple micronozzles, which was previously investigated under steady state condition and significant enhancements were reported. Here, transient wall temperature and overall heat transfer coefficient (HTC) were presented under pulse heating. The impact of heating pulse on flow boiling and two-phase flow regimes was investigated. Additionally, visualizations were synchronized with flow boiling heat transfer characteristics. Comprehensive comparisons were presented to elucidate the effect of this configuration in enhancement of flow boiling performance. Noticeably, the transient HTC was significantly increased by ∼225 % in contrary to plain wall microchannel at 380 kg/m²s.