Slippage on Porous Spherical Superhydrophobic Surface Revolutionizes Heat Transfer of Non‐Newtonian Fluid

Abstract In this study, a new strategy to achieve high‐efficient heat transfer for non‐Newtonian fluids with slippage using a stably prepared superhydrophobic coating is presented. A superhydrophobic coating is prepared on the inner surface of a sleeve at specific shear stress. The slippage and heat‐transfer processes of the typical non‐Newtonian fluid–1% carboxymethyl cellulose solutions on the superhydrophobic coating are investigated simultaneously. A novel porous spherical type of superhydrophobic coating with a contact angle of 168° is obtained. It is found that the shear stress in electrodeposition is a key parameter to control the morphology and wetting ability of the superhydrophobic coating. The slip length and enhancement factor of heat transfer for the non‐Newtonian fluid on the coating are found in a range of 20–900 µm and 1.47 experimentally. A new parameter is proposed as Reynolds number Re divided by the dimensionless slip length l_s* (Re/l_s*) for the heat‐transfer enhancement with slippage, which can be used as the guide for designing coating and selecting the operating conditions. The Re/l_s* is <4, which can enhance the heat transfer via the slippage.