Preparation Of Superhydrophobic Surface Coating On 304 Stainless Steel And Research On Its Scale Inhibition Performance

With the development of modern microelectronics technology,water meter manufacturers have developed new ultrasonic intelligent water meter products.The emergence of intelligent water meters has improved the traditional manual meter reading method and greatly improved the accuracy of measurement.However,in the process of practical application,the surface of the ultrasonic transducer,which is the key measurement device of ultrasonic water meter,is prone to scaling,which affects its service life and measurement accuracy and becomes a common problem in the ultrasonic water meter measurement industry.This study is aimed at 304 stainless steel ultrasonic transducer surface fouling problem,engineering application research.There are studies and engineering practices that show that the superhydrophobic surface has certain advantages in scale inhibition because of its low surface energy and scale crystals are not easy to nucleate and grow on the superhydrophobic surface.In this study,different groove microstructures were obtained on the surface of 304 stainless steel using nanosecond laser etching,and fluorosilane molecular films were prepared on its surface to improve surface hydrophobicity.Firstly,the flow resistance reduction pattern of the microstructure surface in water was analyzed by using fluid simulation software,and this was used to design microstructures with excellent resistance reduction performance and determine their parameters.Different microstructures were etched with a nanosecond laser and the hydrophobic properties and anti-scaling properties of the stainless steel surfaces were experimentally investigated.Two microstructures,namely parallel grooves and bionic radial grooves,were designed on the 304 stainless steel surface by studying the antifouling properties of the microstructures on top of the scalloped surface.The surface microstructure was modeled according to the scale range of laser processing,and the microstructure model was meshed by setting the computational domain and boundary conditions according to the flow field environment in which the ultrasonic water meter works.Subsequently,several numerical simulation methods were compared,the most suitable solution method was selected,and the accuracy of the turbulence model selected in the simulation calculations was verified using selected examples.The effect of the parameters of the surface microstructure on the drag reduction characteristics was investigated using fluid simulation software.The effects of trench width,trench depth and trench spacing on the surface drag reduction were investigated,and the optimal parameter range for the surface microstructure was determined.The shear stresses on the surface of the microstructure were compared,and it was found that a large shear stress exists at the top of the trench surface and is influenced by the fluid flow velocity,while the shear stress at the bottom of the trench is smaller and less influenced by the flow velocity.The velocity field on the microgroove surface was analyzed and it was found that many low velocity fluids gathered on the microgroove surface,which reduced the contact between the surface and the mainstream fluid,thus effectively reducing the drag.Also,on the surface of the bionic radial trench,as the radial angle increases,the low velocity fluid that accumulates on the surface creates small upward vortices on the inner wall of the trench,which helps to scour the inner wall of the trench.Two microstructures,parallel and radial grooves,were obtained by etching the surface of 304 stainless steel with a nanosecond laser,and a fluorosilane molecular film was prepared on the surface to improve surface hydrophobicity.The contact angles measured on the parallel groove surfaces ranged from 132.1° to 151.4°,and the surface energy was characterized by an increase in surface hydrophobicity with decreasing surface groove spacing.Different hydrophobic surfaces were obtained on radial trench surfaces with contact angles ranging from 129.3° to 158.9°,with a gradual decrease in surface hydrophobicity as the surface isometric angle increased.Dynamic scaling experiments were designed to test the scale inhibition properties of 304 stainless steel superhydrophobic samples.The scale inhibition performance of the hydrophobic 304 stainless steel surface increased significantly with the increase of the contact angle.Compared with the fouling amount on the surface of 304 stainless steel,the fouling amount on the surface of 304 stainless steel etched by nanosecond laser and prepared with fluorosilane molecular film on the surface was significantly reduced and had a better scale inhibition effect.304 stainless steel superhydrophobic surface has bubble adsorption on the surface of microstructure in fluid due to the presence of surface air layer,which separates the wall from the solution and acts as a scale inhibition to some extent.In addition,the dynamic environment of the microstructure surface is parallel grooves and radial grooves,the existence of micro-grooves makes the wall surface has certain resistance reduction characteristics,the micro-groove surface has less contact with the mainstream,reducing the momentum exchange,and the reduction of local entropy leads to an increase in the free energy potential barrier,so that the amount of nucleation and the number of nucleation points on the 304 stainless steel surface is reduced,reducing the amount of surface scale generation.