Experimental Investigation And Numerical Simulation Of Dust Particle Dynamic Behavior On Superhydrophobic Surface

With the continuous development of industry,a series of environmental pollution problems have brought great trouble to people,the most notable of which is dust pollution.At present,the phenomenon of dust pollution widely exists in industrial production and people’s daily lives,which will inevitably bring about many problems such as increased energy consumption of equipment and decreased service life.Under such circumstances,how to reduce the deposition of dust on the surface of the equipment has become an urgent problem.Recently,superhydrophobic materials have attracted extensive attention in the related field due to their special advantages of self-cleaning effect.Therefore,based on experiments and numerical simulation,this paper revealed the dust dynamic behavior and deposition mechanism on superhydrophobic surfaces in the dry state.Furthermore,the anti-dust and self-cleaning mechanism of the superhydrophobic surface was disclosed,so as to provide reference and guidance for related research on the preparation of self-cleaning materials.The coating with low surface energy,the coating with micro-nano rough structure,the superhydrophobic coating with low surface energy and rough structure were prepared,respectively.Meanwhile,an ordinary glass surface without coating was also used for comparison.The results showed that the anti-dust effect of superhydrophobic coating was significantly better than that of other self-cleaning coatings.This result was attributed to the combined effect of low surface energy and micro-nano rough structure.Since the existing particle-wall collision model cannot accurately solve the contact force between dust particles and micro-nano rough structure,the concept of rough surface discretization was proposed and the particle-rough surface collision was approximated as particle-discreted smooth surface collision.In addition,based on the proposed collision model,the contact force between particle and rough wall surface was solved accurately.The lattice Boltzmann method(LBM)and discrete element method(DEM)were used to establish the particle migration and deposition model.Subsequently,the model was used to predict the rebound behavior of a single particle on the superhydrophobic surface with regularly distributed structure.The changes of height,velocity and deformation during the collision process between a single particle and the superhydrophobic surface were calculated.The dynamic behavior of a number of particles on the superhydrophobic surface with randomly distributed structures was simulated.The particle deposition rate on the superhydrophobic surface was calculated,thereby revealing the anti-dust mechanism of the superhydrophobic surface.The effects of different factors(surface energy and rough structure)on the particle deposition rate were analyzed and compared.The influence of superhydrophobic surface inside the heat exchanger on the flow and heat transfer characteristics of the particle-laden gas flow in a parallel-plate duct was simulated.Results pointed that the influence of dust on the flow and heat transfer performance was mainly reflected in the fully developed section while the influence of the particles on the entry section was less.For the particle-laden flow,the fully developed section is only "relatively fully developed",and the(f Re)and local Nusselt number along the flow direction constantly fluctuate along the flow direction rather than be stable.The particulate fouling layer formed on the surface can significantly increase the flow resistance and reduce the heat transfer performance.When the surface of the channel became super-hydrophobic,the superhydrophobic surface can effectively reduce the dust deposition and inhibit the formation of the fouling layer on the wall,which effectively reduced the effect of dust particles on the particle-laden gas flow and heat transfer performance of the flow channel.After long time operation,the fluid flow and heat transfer performance only changed slightly.In this paper,the particle dynamic behavior on superhydrophobic surfaces is investigated.The self-cleaning mechanism of superhydrophobic surfaces is revealed,by simulation of the effects of superhydrophobic surfaces on industrial devices.The conclusions can provide some guidance for the design and optimization of superhydrophobic surfaces,extending the related applications in industries.