Previous studies have indicated that piping erosion greatly threatens the safe operation of various hydraulic structures. However, few mathematical models are available to perfectly describe the erosion process due to...Previous studies have indicated that piping erosion greatly threatens the safe operation of various hydraulic structures. However, few mathematical models are available to perfectly describe the erosion process due to the complexity of piping. The focus of the present work is to propose a new fluid solid coupling model to eliminate the shortcomings of existing work. A 'pseudo-liquid' assumption is suggested to simulate the particle movement in the erosion process. Then, based on the mass and momentum conservations of the moving particles and flowing water, a new two-flow model is established by using the continuity equations and motion equations. In the model, the erosion rate of soil is determined with a particle erosion law derived from tests results of STERPI. And ERGUN's empirical equation is used to determine the interaction forces between the liquid and the solid. A numerical approach is proposed to solve the model with the finite volume method and SIMPLE algorithm. The new model is validated with the tests results of STERPI. And the soil erosion principles in piping are also explored.展开更多
The immense energy potential of natural water vapor cycles,encompassing evaporation,transport,and adsorption,remains substantially underexploited.Recent progress in nanomaterial science and an improved understanding o...The immense energy potential of natural water vapor cycles,encompassing evaporation,transport,and adsorption,remains substantially underexploited.Recent progress in nanomaterial science and an improved understanding of water-surface interactions have shown that because of quantum confinement effects and increased surface reactivity,nanoscale materials have exceptional electrical generation abilities through interfacial dynamics with aqueous phases.Hydrovoltaic technology has emerged as a novel energy conversion method that harnesses liquid-solid interfacial phenomena including surface slippage,frictional contact,evaporation dynamics,and moisture concentration gradients to produce electrical outputs.This review summarizes advances in graphene-based carbon materials for hydrovoltaic applications,addressing four critical aspects:(1)fundamental characteristics of graphene-water interfaces,(2)interfacial charge generation mechanisms at liquid-solid boundaries,(3)three principal electricity generation modes(flow-induced,evaporation-driven,and moisture gradient-enabled power generation),and(4)practical implementation scenarios.We also propose ways to improve the energy conversion efficiency and scale-up of the current technology for its use in self-powered systems,flexible energy storage batteries,humidity sensors,and personal thermal management devices.展开更多
基金Foundation item： Project（2011BAB09B01） supported by the National Science and Technology Support Program of China Project（cstc2013jcyjA30006） supported by Chongqing Science ＆ Technology Commission, China Project（K J130412） supported by Chongqing Education Commission, China
文摘Previous studies have indicated that piping erosion greatly threatens the safe operation of various hydraulic structures. However, few mathematical models are available to perfectly describe the erosion process due to the complexity of piping. The focus of the present work is to propose a new fluid solid coupling model to eliminate the shortcomings of existing work. A 'pseudo-liquid' assumption is suggested to simulate the particle movement in the erosion process. Then, based on the mass and momentum conservations of the moving particles and flowing water, a new two-flow model is established by using the continuity equations and motion equations. In the model, the erosion rate of soil is determined with a particle erosion law derived from tests results of STERPI. And ERGUN's empirical equation is used to determine the interaction forces between the liquid and the solid. A numerical approach is proposed to solve the model with the finite volume method and SIMPLE algorithm. The new model is validated with the tests results of STERPI. And the soil erosion principles in piping are also explored.
文摘The immense energy potential of natural water vapor cycles,encompassing evaporation,transport,and adsorption,remains substantially underexploited.Recent progress in nanomaterial science and an improved understanding of water-surface interactions have shown that because of quantum confinement effects and increased surface reactivity,nanoscale materials have exceptional electrical generation abilities through interfacial dynamics with aqueous phases.Hydrovoltaic technology has emerged as a novel energy conversion method that harnesses liquid-solid interfacial phenomena including surface slippage,frictional contact,evaporation dynamics,and moisture concentration gradients to produce electrical outputs.This review summarizes advances in graphene-based carbon materials for hydrovoltaic applications,addressing four critical aspects:(1)fundamental characteristics of graphene-water interfaces,(2)interfacial charge generation mechanisms at liquid-solid boundaries,(3)three principal electricity generation modes(flow-induced,evaporation-driven,and moisture gradient-enabled power generation),and(4)practical implementation scenarios.We also propose ways to improve the energy conversion efficiency and scale-up of the current technology for its use in self-powered systems,flexible energy storage batteries,humidity sensors,and personal thermal management devices.
