Experimental Investigation of the Effects of Superhydrophobic and Superhydrophilic Surfaces on the Pulsating Heat Pipe

Effects of superhydrophobic surface and superhydrophobic and superhydrophilic hybrid surface on the fluid flow of PHPs were investigated.The inner surfaces of the PHPs were hydrophilic surface(copper),hybrid surface(superhydrophilic evaporation and superhydrophobic condensation section),and uniform superhydrophobic surface,respectively.Visualization results showed that the liquid-vapor interface was concave in the copper PHP.On the contrary,the liquid-vapor interface took a convex profile in the PHP with superhydrophobic surface and the liquid-vapor interface length in the hybrid surface PHP was higher than that in the uniform superhydrophobic surface PHP.The partial dryout phenomenon took place in PHPs with uniform superhydrophobic surface and the liquid slug movements became weaker.