The influence of the surface galvanic effects of 1Cr13 SS during cavitation damage has been investigated in NaCl solutions. The results show that the solution concentration and area ratio of bubble unacted surface to ...The influence of the surface galvanic effects of 1Cr13 SS during cavitation damage has been investigated in NaCl solutions. The results show that the solution concentration and area ratio of bubble unacted surface to the bubble-acted surface greatly influence the cavitation damage of the alloy. The surface galvanic effects can speed up the dissolution rate of the alloy, and the mass loss per area of the alloy increases linearly with the area ratio of bubble unacted surface to the bubble acted surface of the alloy.展开更多
This paper presents numerical studies of the Magnus effect for a kinetic turbine on a horizontal axis.To focus on the Magnus blade,a single self-spinning cylindrical blade is assumed.An iterative direct-forcing immers...This paper presents numerical studies of the Magnus effect for a kinetic turbine on a horizontal axis.To focus on the Magnus blade,a single self-spinning cylindrical blade is assumed.An iterative direct-forcing immersed boundary method is employed within the Eulerian-Lagrangian framework due to its capability to treat complex and moving geometries.The Eulerian fluid domain is discretized using the finite volume method while the Magnus rotor is represented by a set of discrete points/markers.The aim of the numerical studies is to provide insights for the design process and predict aerodynamic performances under various operating conditions.Results for stationary and self-spinning cylinders in turbulent flows are found to be in good agreement with published data.By increasing the aspect ratio of the cylinder(simulated segment length over its diameter)from 3 to 10,a 30%drop in lift coefficient and a 22%increase in drag coefficient were observed,which is believed to be attributed to an enhancement of the three-dimensionality of the near-wake.For the Magnus rotor,key parameters such as dynamic forcing and frequency,distribution of pressure coefficient and torque have been produced for two cases with different structural designs and working conditions.With increase of the aspect ratio from 3 to 10,stable forces are observed from the root side of the blade and the torque coefficient increases from 0.68 to 2.1,which indicates a superior performance in terms of power extraction.展开更多
文摘The influence of the surface galvanic effects of 1Cr13 SS during cavitation damage has been investigated in NaCl solutions. The results show that the solution concentration and area ratio of bubble unacted surface to the bubble-acted surface greatly influence the cavitation damage of the alloy. The surface galvanic effects can speed up the dissolution rate of the alloy, and the mass loss per area of the alloy increases linearly with the area ratio of bubble unacted surface to the bubble acted surface of the alloy.
文摘This paper presents numerical studies of the Magnus effect for a kinetic turbine on a horizontal axis.To focus on the Magnus blade,a single self-spinning cylindrical blade is assumed.An iterative direct-forcing immersed boundary method is employed within the Eulerian-Lagrangian framework due to its capability to treat complex and moving geometries.The Eulerian fluid domain is discretized using the finite volume method while the Magnus rotor is represented by a set of discrete points/markers.The aim of the numerical studies is to provide insights for the design process and predict aerodynamic performances under various operating conditions.Results for stationary and self-spinning cylinders in turbulent flows are found to be in good agreement with published data.By increasing the aspect ratio of the cylinder(simulated segment length over its diameter)from 3 to 10,a 30%drop in lift coefficient and a 22%increase in drag coefficient were observed,which is believed to be attributed to an enhancement of the three-dimensionality of the near-wake.For the Magnus rotor,key parameters such as dynamic forcing and frequency,distribution of pressure coefficient and torque have been produced for two cases with different structural designs and working conditions.With increase of the aspect ratio from 3 to 10,stable forces are observed from the root side of the blade and the torque coefficient increases from 0.68 to 2.1,which indicates a superior performance in terms of power extraction.
