An advanced theoretical model of a U-shaped minichannel, a building block of a closed-end oscillating heat pipe, has been developed. Thin film evaporation in the evaporator and thin film condensation in the condenser, axial variation of surface temperature, and pressure loss at the bend are incorporated in this model. The sensible heat transfer coefficients between the liquid slug and the wall are obtained by analytical solution for laminar liquid flow and by empirical correlations for turbulent liquid flow. The effects of the inner diameter, evaporator temperature on the thermally induced oscillatory flow and heat transfer performance, and the mechanism of film condensation and evaporation are investigated.

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