EXPERIMENTAL STUDY ON DRAG REDUCTION CHARACTERISTICS OF POLYMER-SELF-POLISHING PAINT COMPOSITE COATING

Based on the advantages of the drag reduction coating (easy engineering application) and the polymer (excellent turbulent drag reduction performance), the development of composite polymer drag reduction coating would have a broad application prospect in the field of ships and underwater vehicles, but there is still a relative lack of research in this field. Thus, the present work prepared domestic self-polishing paint composite coatings based on PAM and PEO drag reducing agents, and investigated the influence of coating types, flow velocity and PAM/PEO concentration on the drag reduction performance through the underwater plate resistance test, and surface roughness. The results showed that polymer-self-polishing paint composite coating has drag reduction effect, which can produce 9.4% drag reduction by using single-sided drag reduction coating; Flow velocity variations have a little influence on the drag reduction rate, and the induced variation of the drag reduction rate was smaller than 3.5%; When increasing the polymer concentration, the drag reduction rate of self-polishing paint-PAM coating first increased and then decreased, while the drag reduction rate of self-polishing paint-PEO coating first kept stable and then decreased rapidly; When the polymer concentration exceeded a certain critical value, the drag reduction rate decreased, and the coating even increased the flow drag. This is because the surface roughness of the coating increased and the viscosity of the solution changed when adding too many polymers. This work would provide supports for the engineering application of polymer drag reduction coating.