Study about heat transfer coefficient of water-nanofluid in pulsating heat pipes

Pulsating heat pipe is an efficient heat exchange device which is being used for cooling and heating recovery. In the present work, we made a closed-loop pulsating heat pipe with six U-turns and we used water in our system. Moreover the use of water-Fe3O4 nanofluid was studied with two different filling ratios 40% and 50% and 1% mass concentration. At the end we calculated heat resistance and heat transfer coefficients of water and water-Fe3O4 nanofluid in each step and compared the results and showed that 50% filling ratio was the best in our study. And water-Fe3O4 nanofluid has better heat transfer coefficient than water.