In this work the authors present a calculation process of the blades for wind turbine with horizontal axis. It is about a blade discretized by the finite element method （FEM） in order to determine the gyroscopic eff...In this work the authors present a calculation process of the blades for wind turbine with horizontal axis. It is about a blade discretized by the finite element method （FEM） in order to determine the gyroscopic effect during its rotation at a high speed. A blade must have the maximum output and resist to aerodynamic loads distributed over its length, which are related to its geometrical characteristics and the speed of the wind. For that, the authors wrote the relations whom determine these loads according to the flow speed of the wind, then, the authors integrated them in the laws of structure mechanics to obtain the motion equations of the blade. This process was applied to a twisted blade with a length of 1.9 m, built out of pressed aluminum sheet with a profile of the type NACA; this profile gives the best aerodynamic output. This blade is an element of a three-bladed propeller for wind turbine of maximum power 5 kW. Finally, we visualized its deformations and then the authors checked its holding in service.展开更多
The purpose of college English teaching is to cultivate students ＇ English proficiency, one is listening, speaking, reading, writing, translation ability, on the other hand is the ability to think in English. Among t...The purpose of college English teaching is to cultivate students ＇ English proficiency, one is listening, speaking, reading, writing, translation ability, on the other hand is the ability to think in English. Among them, listening, reading is input, speaking, writing, translation is output. Chinese college students is learning foreign language in a non-native environment, which requires students to have a certain amount of input, output while there are plenty of opportunities; English thinking mainly refers to the critical thinking skills （Critical thinking）, which is using fluent English to consider things speculatively and express their views on the basis of listening, speaking reading, writing, and the translation.展开更多
文摘In this work the authors present a calculation process of the blades for wind turbine with horizontal axis. It is about a blade discretized by the finite element method （FEM） in order to determine the gyroscopic effect during its rotation at a high speed. A blade must have the maximum output and resist to aerodynamic loads distributed over its length, which are related to its geometrical characteristics and the speed of the wind. For that, the authors wrote the relations whom determine these loads according to the flow speed of the wind, then, the authors integrated them in the laws of structure mechanics to obtain the motion equations of the blade. This process was applied to a twisted blade with a length of 1.9 m, built out of pressed aluminum sheet with a profile of the type NACA; this profile gives the best aerodynamic output. This blade is an element of a three-bladed propeller for wind turbine of maximum power 5 kW. Finally, we visualized its deformations and then the authors checked its holding in service.
文摘The purpose of college English teaching is to cultivate students ＇ English proficiency, one is listening, speaking, reading, writing, translation ability, on the other hand is the ability to think in English. Among them, listening, reading is input, speaking, writing, translation is output. Chinese college students is learning foreign language in a non-native environment, which requires students to have a certain amount of input, output while there are plenty of opportunities; English thinking mainly refers to the critical thinking skills （Critical thinking）, which is using fluent English to consider things speculatively and express their views on the basis of listening, speaking reading, writing, and the translation.
