Effect of ultrasonic on the enhancement of heat transfer for pulsating heat pipe

The pulsating heat pipe (PHP) has become one of the most promising devices to dramatically remove heat for electronic devices. This work focuses on the experimental investigation of ultrasonic on the enhancement of heat transfer of PHP, and further discusses this effect at the different working fluids. The results indicate that the external region of PHP exhibits more intense oscillation motion of working fluids than that of internal-region. The heat transfer performance enhanced assisted with the ultrasonic at the heating power of 5 to 20 W but deteriorated at 25 W. For details, the heat transfer coefficient (HTC) increased 72.6%, and the internal and external start-up times reduced 57.8% and 2.2%, respectively. Furthermore, the numerous vapors confirm that the ultrasonic cavitation would effectively accelerate the phase transition. Finally, it also discusses the couple effect between the ultrasonic and different working fluids on heat transfer coefficient. The maximum HTC of 1.85 is obtained at the heating power of 15 W for the PHP charged with acetone. In addition, the trend of HTC of PHP filled with acetone shows much more stable assisted with ultrasonic varying from the heating power inputs. Highlights The thermal performance was revealed by internal and external region of PHP The directly enhanced method of ultrasonic cavitation was introduced The novel index of the heat transfer coefficient (HTC) was proposed The couple effect ultrasonic on the enhancement of heat transfer was discussed with different working fluids

Automated summary

This study experimentally investigated the effect of ultrasonic on the heat transfer performance of a pulsating heat pipe (PHP), showing that ultrasonic can enhance heat transfer performance at certain heating powers while also causing deterioration at higher powers. Furthermore, the presence of more vapors confirms that ultrasonic cavitation effectively accelerates phase transition.