LAUSR

Abstract The flow characteristics and thermal performance of an MEMS-based micro oscillating heat pipe (micro-OHP) were experimentally investigated using dielectric liquid HFE-7100 as working fluid. The micro-OHP was integrated on a silicon wafer with trapezoidal channels having a hydraulic diameter of 357 μm. The gravity action on the micro-OHP performance functioned greatly and could not be ignored. High-speed visual observation demonstrated the annular/semi-annular flow, injection/slug flow, and bubbly flow in the micro-OHP. The alternate “small-amplitude oscillation phase (SAOP)—large-amplitude oscillation phase (LAOP)” was verified in this micro-OHP at the quasi-steady oscillation state, and its performance improvement was attributable to the extended time ratio of LAOP. In addition, the ephemeral circulation flow and bubble nucleation were observed intermittently. The occurrence of dry-out mainly appeared at lower filling ratios and higher power inputs.