Measurement Of Solid-liquid Interface Friction Resistance And Research On Drag Reduction Mechanism Of Superhydrophobic Surface

With the depletion of the earth’s resources,reducing energy consumption and improving equipment operation efficiency have gradually become the primary tasks facing scientists and engineers.Therefore,in recent years,the research on drag reduction technology and drag reduction effect evaluation technology has attracted more and more attention.In the determination of technical solutions such as liquid transportation,air and underwater navigation,and the study of bypass problems,people inevitably have to encounter the measurement and calculation of motion resistance.In addition to the pressure difference resistance caused by the separation of the fluid-solid surface boundary layer,the friction generated by the mutual movement of the fluid-solid surface has also become the focus of attention.In this study,we measured the frictional resistance of different speeds of water flowing through two superhydrophobic surfaces through a self-designed and built test device;through theoretical analysis,the reason for the drag reduction of superhydrophobic surfaces was preliminarily explained.The main research contents are as follows:(1)A channel type measuring device is designed and constructed,which combines flow pressure drop experiment with sensor direct measurement.The overall design of the device and the determination of various parts are mainly carried out,in order to be able to be used to characterize the drag reduction performance of the super-hydrophobic surface in the channel.(2)Firstly,the solid-liquid interface friction resistance measurement device was used to measure the friction resistance of acrylic surface,and then the friction resistance performance of lotus leaf surface and shark skin like swimsuit fabric in different pasting ways was characterized by the friction resistance measurement device and the friction resistance of acrylic surface.(3)We established the contact model between the lotus leaf surface microstructure(uniformly distributed parabolic cone)and shark skin like swimsuit fabric microstructure(herringbone semi cylinder)and liquid,and calculated the actual contact area between lotus leaf and shark skin like swimsuit fabric and water under different pasting methods,The results show that the contact area between liquid and solid surface is the key factor affecting the change of solid-liquid interface friction resistance;And the friction resistance per unit area of different surfaces under different pasting methods is calculated.The calculation results verify the feasibility and accuracy of the resistance test device again.