When an aircraft passes through a rainy area at high speed,the coating on the front edge of the fuselage will be continuously eroded by raindrops,causing the coating to wear,crack or even peel off.This paper uses carb...When an aircraft passes through a rainy area at high speed,the coating on the front edge of the fuselage will be continuously eroded by raindrops,causing the coating to wear,crack or even peel off.This paper uses carbon fiber T300 material as the base material,and at the different impact speeds and impact numbers,water cutting equipment was used to simulate the erosion of the coating caused by the continuous impact of water droplets.The damage morphology of samples at different damage stages was observed by digital microscope and Scanning Electron Microscope(SEM),and the damage evolution curve was established to analyze and reveal the damage behavior and damage mechanism of rain erosion.The results show that the degree of damage experienced an increasing trend with the increase of impact numbers and speed,until circular peel damage was formed;no damage occurred during the incubation period,and the curvature of the damage evolution curve increased significantly after the expansion period and eventually showed a stable expansion trend.The mechanical properties of the coating material were the main influencing factors of its rain corrosion resistance.Moreover,the axially symmetric unsteady contact problem of droplets impacting the surface of a solid deformable body was studied.And the contact area was determined based on the iterative algorithm boundary positioning method.A mathematical model and closed mathematical formula describing the unsteady interaction between a droplet and a solid deformable obstacle were proposed.展开更多
The microscopic morphology and pore structure characteristics of concrete with composite admixtures(fly ash and mineral powder) after chlorine salt erosion were analyzed via scanning electron microscopy(SEM) and mercu...The microscopic morphology and pore structure characteristics of concrete with composite admixtures(fly ash and mineral powder) after chlorine salt erosion were analyzed via scanning electron microscopy(SEM) and mercury injection porosimetry(MIP), providing the basis for the design and maintenance of concrete shafts in coal mines. The above-mentioned characteristics were compared with the macroscopic characteristic of concrete fractures under uniaxial compression. The results show that the macroscopic fracture characteristics of concrete under uniaxial compression change from longitudinal split fracture and oblique section shear fracture to conjugate cant fracture, and the degree of breakage increases.Interface cracks, cement paste cracks, spherical surface cracks, and aggregate cracks appear in concrete under uniaxial compression. In the early stages of corrosion, the original cracks which are obvious are repaired. When the corrosion becomes more serious, cement paste cracks appear, and the number of harmful holes increases while the number of harmless holes decreases. This study also reveals the relationship between the macroscopic properties and microscopic structure of concrete under chloride salt erosion. Finally, the paper preliminarily discussed the relationship between the macroscopic properties and mesoscopic characteristics of concrete under chlorine salt erosion.展开更多
The centrifugal slurry pump is widely applied for the transportation of liquid medium containing solid particles.The introduction of solid particles will lead to a decrease in efficiency and wear of the slurry pump.To...The centrifugal slurry pump is widely applied for the transportation of liquid medium containing solid particles.The introduction of solid particles will lead to a decrease in efficiency and wear of the slurry pump.To solve this problem,it is imperative to review the hydraulic performance and erosion characteristic of slurry pumps under solid-liquid two-phase flow in recent years.In this review,firstly,the general structure and engineering application are introduced.Next,the experimental and simulation research methods of particle movement and erosion wear are explored.Then,the influence of solid particles on the hydraulic performance and particle distribution is analyzed.Afterwards,the variation laws of erosion wear under different flow-passing components and particle properties are clarified.Finally,according to the current research status and conclusions,the design optimization measures and future investigate direction are proposed,aiming to promote the resolution of wear damage and extend the service life of the slurry pump.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.12261131505,62005172)the Russian Science Fund(No.23-49-00133)+1 种基金the Fundamental Research Funds for the Central Universities,China(No.D5000210517)the Basic Research Programs of Taicang,China(No.TC2021JC21).
文摘When an aircraft passes through a rainy area at high speed,the coating on the front edge of the fuselage will be continuously eroded by raindrops,causing the coating to wear,crack or even peel off.This paper uses carbon fiber T300 material as the base material,and at the different impact speeds and impact numbers,water cutting equipment was used to simulate the erosion of the coating caused by the continuous impact of water droplets.The damage morphology of samples at different damage stages was observed by digital microscope and Scanning Electron Microscope(SEM),and the damage evolution curve was established to analyze and reveal the damage behavior and damage mechanism of rain erosion.The results show that the degree of damage experienced an increasing trend with the increase of impact numbers and speed,until circular peel damage was formed;no damage occurred during the incubation period,and the curvature of the damage evolution curve increased significantly after the expansion period and eventually showed a stable expansion trend.The mechanical properties of the coating material were the main influencing factors of its rain corrosion resistance.Moreover,the axially symmetric unsteady contact problem of droplets impacting the surface of a solid deformable body was studied.And the contact area was determined based on the iterative algorithm boundary positioning method.A mathematical model and closed mathematical formula describing the unsteady interaction between a droplet and a solid deformable obstacle were proposed.
基金The authors gratefully acknowledge the financial support for this work,provided by the Outstanding Youth Science Foundation of China(No.51322401)the Key Project of Chinese National Programs for Fundamental Research and Development of China(No.2015CB251601)+1 种基金the Science and Technology Project of the Chinese Ministry of Housing and Urban-Rural Construction of China(Nos.2013-K4-22 and 2014-K4-042)the General Program of Chinese National Building Materials Industry Technology Innovation Program of China(Nos.2014-M5-1 and 2014-M5-2)
文摘The microscopic morphology and pore structure characteristics of concrete with composite admixtures(fly ash and mineral powder) after chlorine salt erosion were analyzed via scanning electron microscopy(SEM) and mercury injection porosimetry(MIP), providing the basis for the design and maintenance of concrete shafts in coal mines. The above-mentioned characteristics were compared with the macroscopic characteristic of concrete fractures under uniaxial compression. The results show that the macroscopic fracture characteristics of concrete under uniaxial compression change from longitudinal split fracture and oblique section shear fracture to conjugate cant fracture, and the degree of breakage increases.Interface cracks, cement paste cracks, spherical surface cracks, and aggregate cracks appear in concrete under uniaxial compression. In the early stages of corrosion, the original cracks which are obvious are repaired. When the corrosion becomes more serious, cement paste cracks appear, and the number of harmful holes increases while the number of harmless holes decreases. This study also reveals the relationship between the macroscopic properties and microscopic structure of concrete under chloride salt erosion. Finally, the paper preliminarily discussed the relationship between the macroscopic properties and mesoscopic characteristics of concrete under chlorine salt erosion.
基金supported by The National Natural Science Foundation of China (grant No.52222601).
文摘The centrifugal slurry pump is widely applied for the transportation of liquid medium containing solid particles.The introduction of solid particles will lead to a decrease in efficiency and wear of the slurry pump.To solve this problem,it is imperative to review the hydraulic performance and erosion characteristic of slurry pumps under solid-liquid two-phase flow in recent years.In this review,firstly,the general structure and engineering application are introduced.Next,the experimental and simulation research methods of particle movement and erosion wear are explored.Then,the influence of solid particles on the hydraulic performance and particle distribution is analyzed.Afterwards,the variation laws of erosion wear under different flow-passing components and particle properties are clarified.Finally,according to the current research status and conclusions,the design optimization measures and future investigate direction are proposed,aiming to promote the resolution of wear damage and extend the service life of the slurry pump.
