Effect of Silver Nanofluid on the Thermal Characteristics of Flat Plate Pulsating Heat Pipe

In this paper, the silver nanofluid with strong ion activity, low viscosity and excellent thermal conductivity is applied to the flat plate pulsating heat pipe (FP-PHP), the three-dimensional geometric model of FP-PHP with microchannel at the condensing section is established. A visual experiment platform is built independently to verify the reliability of the simulation results. The visualization phenomenon found that the types of bubbles of silver nanofluid are varied, including bubbly flow, plug flow, annular flow, semi-annular flow, and staggered cluster flow. With the increase of heating power, the stable cycle time gradually shortens, the flow pattern changes rapidly, and the cycle shortens. The thermal characteristics found that when the heating power reaches 110 W, the thermal resistance of nano silver fluid is the smallest, only 0.40 K/W. At this time, the heat transfer coefficient is 33% higher than that of the working fluid. The starting temperature of silver nanofluid is relatively low, only 35 ℃. Excellent temperature uniformity, after the heating power reaches 70 W, the overall temperature pulsation is only 1.2 ℃.