This paper describes a dual-stroke acting hydraulic power take-off （PTO） system employed in the wave energy converter （WEC） with an inverse pendulum. The hydraulic PTO converts slow irregular reciprocating wave mo...This paper describes a dual-stroke acting hydraulic power take-off （PTO） system employed in the wave energy converter （WEC） with an inverse pendulum. The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth, fast rotation of an electrical generator. The design of the hydraulic PTO system and its control are critical to maximize the generated power. A time domain simulation study and the laboratory experiment of the full-scale beach test are presented. The results of the simulation and laboratory experiments including their comparison at full-scale are also presented, which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.展开更多
The solid-liquid separation is an important operation for the regenerated slurry of dual-alkali FGD system,and calcium sulfite could predominate in particle aggregates of the slurry.The settling velocity of calcium su...The solid-liquid separation is an important operation for the regenerated slurry of dual-alkali FGD system,and calcium sulfite could predominate in particle aggregates of the slurry.The settling velocity of calcium sulfite particles is a key parameter for the solid-liquid separation design.However,the settling velocity predicted by Stokes' Law could be suitable only for a spherical aggregate, but not for the irregular one.In this work,fractal geometry was introduced in order to characterize highly irregular geometric shapes.The sizes of calcium sulfite particle aggregates were analyzed using a metallographic phase microscope and image analysis.The results showed that particle aggregates had fractal features.The fractal dimensions could reveal the characteristics of the aggregates' geometry and aggregation process.An exponential relation between the fractal dimension D_2 and the particle size l was determined as A∝l^(D2). According to fractal theory,a parameter can be used to modify Stokes settling velocity close to actual settling velocity.The results could be valuable for the design of solid-liquid separation processes.展开更多
In this article, the unsteady magnetohydrodynamic （MHD） stagnation point flow and heat transfer of a nanofluid over a stretching/shrinking sheet is investigated numerically. The similarity solution is used to reduce...In this article, the unsteady magnetohydrodynamic （MHD） stagnation point flow and heat transfer of a nanofluid over a stretching/shrinking sheet is investigated numerically. The similarity solution is used to reduce the governing system of partial differential equations to a set of nonlinear ordinary differential equations which are then solved numerically using the fourth-order Runge-Kutta method with shooting technique. The ambient fluid velocity, stretching/shrinking velocity of sheet, and the wall temperature are assumed to vary linearly with the distance from the stagnation point. To investigate the influence of various pertinent parameters, graphical results for the local Nusselt number, the skin friction coefficient, velocity profile, and temperature profile are presented for different values of the governing parameters for three types of nanoparticles, namely copper, alumina, and titania in the water-based fluid. It is found that the dual solution exists for the decelerating flow. Numerical results show that the extent of the dual solution domain increases with the increases of velocity ratio, magnetic parameter, and permeability parameter whereas it remains constant as the value of solid volume fraction of nanoparticles changes. Also, it is found that permeability parameter has a greater effect on the flow and heat transfer of a nanofluid than the magnetic parameter.展开更多
A novel unsymmetrical fluorescein derivative substituted by chlorine and naphthol, 2 '-chloroseminaphthofluorescein, was prepared by the two-step synthetic method. This method can effectively control the reactive ...A novel unsymmetrical fluorescein derivative substituted by chlorine and naphthol, 2 '-chloroseminaphthofluorescein, was prepared by the two-step synthetic method. This method can effectively control the reactive process,so the pure unsymmetrical fluorescein derivative can be obtained in high yield. The new fluorophore exhibited dual absorption bands,dual excitation bands and dual emission bands with long-wavelength,selectively exciting the acidic and basic forms of the fluorophore. Compared with the similar symmetrical fluorescein derivatives such as 2 ', 7 '-dichlorofluorescein and dinaphtofluorescein, this fluorophore was found to have larger Stokes shift,especially in the basic form. Based on the properties above,this unsymmetrical fluorescein derivative is expected as a good fluorescent probe to be used where the interference exists due to the presence of endogenous fluorescers.展开更多
In the present paper, the flow field of dual rectangular jets was numerically simulated by solving the full Reynolds averaged Navier Stokes equations , where the RNG k ε model and the finite volume method were ...In the present paper, the flow field of dual rectangular jets was numerically simulated by solving the full Reynolds averaged Navier Stokes equations , where the RNG k ε model and the finite volume method were used. The flow structure in dual rectangular jets and the effects of the velocity were investigated. The numerical results agree qualitatively with the experimental data.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51205346 and 41206074)the National High Technology Research and Development Program of China(863 Program+3 种基金Grant No.2011AA050201)Science Fund for Creative Research Groups of National Natural Science Foundation of China(Grant No.51221004)Zhejiang Provincial Natural Science Foundation of China(Grant No.LY12E05017)Open Foundation of the State Key Laboratory of Fluid Power Transmission and Control(Grant No.GZKF-201311)
文摘This paper describes a dual-stroke acting hydraulic power take-off （PTO） system employed in the wave energy converter （WEC） with an inverse pendulum. The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth, fast rotation of an electrical generator. The design of the hydraulic PTO system and its control are critical to maximize the generated power. A time domain simulation study and the laboratory experiment of the full-scale beach test are presented. The results of the simulation and laboratory experiments including their comparison at full-scale are also presented, which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.
基金Supported by the National Hi-tech Research and Development Program (863 Program) of China (No.2001AA642030-1)New Century Excellent Scholar Program of Ministry of Education of China (No.NCET-04-0549)The Key Research Project of Zhejiang Province (No.010007037)
文摘The solid-liquid separation is an important operation for the regenerated slurry of dual-alkali FGD system,and calcium sulfite could predominate in particle aggregates of the slurry.The settling velocity of calcium sulfite particles is a key parameter for the solid-liquid separation design.However,the settling velocity predicted by Stokes' Law could be suitable only for a spherical aggregate, but not for the irregular one.In this work,fractal geometry was introduced in order to characterize highly irregular geometric shapes.The sizes of calcium sulfite particle aggregates were analyzed using a metallographic phase microscope and image analysis.The results showed that particle aggregates had fractal features.The fractal dimensions could reveal the characteristics of the aggregates' geometry and aggregation process.An exponential relation between the fractal dimension D_2 and the particle size l was determined as A∝l^(D2). According to fractal theory,a parameter can be used to modify Stokes settling velocity close to actual settling velocity.The results could be valuable for the design of solid-liquid separation processes.
文摘In this article, the unsteady magnetohydrodynamic （MHD） stagnation point flow and heat transfer of a nanofluid over a stretching/shrinking sheet is investigated numerically. The similarity solution is used to reduce the governing system of partial differential equations to a set of nonlinear ordinary differential equations which are then solved numerically using the fourth-order Runge-Kutta method with shooting technique. The ambient fluid velocity, stretching/shrinking velocity of sheet, and the wall temperature are assumed to vary linearly with the distance from the stagnation point. To investigate the influence of various pertinent parameters, graphical results for the local Nusselt number, the skin friction coefficient, velocity profile, and temperature profile are presented for different values of the governing parameters for three types of nanoparticles, namely copper, alumina, and titania in the water-based fluid. It is found that the dual solution exists for the decelerating flow. Numerical results show that the extent of the dual solution domain increases with the increases of velocity ratio, magnetic parameter, and permeability parameter whereas it remains constant as the value of solid volume fraction of nanoparticles changes. Also, it is found that permeability parameter has a greater effect on the flow and heat transfer of a nanofluid than the magnetic parameter.
基金The National Natural Science Foundation of China(11701451)the Natural Science Foundation of Shaanxi Province(2018JQ1077)+1 种基金the Scientific Research Program Funded by Education Department of Shaanxi Province(17JK0787)the Young Talent Fund of University Association for Science and Technology in Shaanxi(20180504)
基金National Natural Science Foundations of China(Nos.51203018,21171034)the Fundamental Research Funds for the Central Universities,China(No.2232015D3-14)
文摘A novel unsymmetrical fluorescein derivative substituted by chlorine and naphthol, 2 '-chloroseminaphthofluorescein, was prepared by the two-step synthetic method. This method can effectively control the reactive process,so the pure unsymmetrical fluorescein derivative can be obtained in high yield. The new fluorophore exhibited dual absorption bands,dual excitation bands and dual emission bands with long-wavelength,selectively exciting the acidic and basic forms of the fluorophore. Compared with the similar symmetrical fluorescein derivatives such as 2 ', 7 '-dichlorofluorescein and dinaphtofluorescein, this fluorophore was found to have larger Stokes shift,especially in the basic form. Based on the properties above,this unsymmetrical fluorescein derivative is expected as a good fluorescent probe to be used where the interference exists due to the presence of endogenous fluorescers.
文摘In the present paper, the flow field of dual rectangular jets was numerically simulated by solving the full Reynolds averaged Navier Stokes equations , where the RNG k ε model and the finite volume method were used. The flow structure in dual rectangular jets and the effects of the velocity were investigated. The numerical results agree qualitatively with the experimental data.
