Experimental study of flow boiling heat transfer characteristics in small channels under mechanical vibration

Through visualization experiments, this study reveals the variation patterns and underlying mechanisms of flow boiling heat transfer characteristics in small channels under mechanical vibration. The research finds that the heat transfer performance is enhanced under the influence of vibration, but the heat flow density exceeds 13347W/m², the heat transfer performance is no longer with the increase of vibration intensity in a single trend of enhancement. Instead, with the increase in vibration acceleration, both the heat transfer coefficient and the average wall temperature show a serpentine fluctuation. The best heat transfer performance was observed at 11.59 m/s² and 34.785 m/s² acceleration, with a maximum increase of approximately 47.6 % compared to the static channel and a wall temperature reduction of 2.65 K. The main reason for this is that the shape of the bubbles undergoes complex changes with phase position, which not only increases the gas-liquid contact area but also enhances the perturbation of the thermal boundary layer. When the acceleration reaches 15.46 m/s², the merging of elongated bubbles weakens the heat transfer effect. With further increase in vibration acceleration, the bubble detachment was enhanced.