Small propeller-type wind turbines have a low Reynolds number,limiting the number of usable airfoil materials.Thus,their design method is not sufBciently established,and their performance is often low.The ultimate goa...Small propeller-type wind turbines have a low Reynolds number,limiting the number of usable airfoil materials.Thus,their design method is not sufBciently established,and their performance is often low.The ultimate goal of this research is to establish high-performance design guidelines and design methods for small propeller-type wind turbines.To that end,we designed two rotors:Rotor A,based on the rotor optimum design method from the blade element momentum theory,and Rotor B,in which the chord length of the tip is extended and the chord length distribution is linearized.We examined performance characteristics and flow fields of the two rotors through wind tunnel experiments and numerical analysis.Our results revealed that the maximum output tip speed ratio of Rotor B shifted lower than that of Rotor A,but the maximum output coefficient increased by approximately 38.7%.Rotors A and B experienced a large-scale separation on the hub side,which extended to the mean in Rotor A.This difference in separation had an impact on the significant decrease in Rotor A's output compared to the design value and the increase in Rotor B's output compared to Rotor A.展开更多
During the process of local post-weld heat treatment （ PWHT） , the temperature difference inside the weld overlay is a very influential factor on relieving residual stress. In this paper, a commercial program （ABA...During the process of local post-weld heat treatment （ PWHT） , the temperature difference inside the weld overlay is a very influential factor on relieving residual stress. In this paper, a commercial program （ABAQUS） was used to simulate the temperature field in turbine rotor, and the influence of heat treatment parameters on temperature was investigated by finite element method. Weight analysis shows that the holding temperature and heating rate are the main factors affecting on temperature, especially the holding temperature. Besides, two regression equations that reflect the relationship between temperature and heat treatment parameters were fitted with uniform design method. Both the correlation coefficients of the regression equations are up to O. 999 2, and the maximum residual error is only O. 7. The agreement between simulation results and regression results is shown to be excellent. At the end, local heat treatment parameters were optimized using the simplex method.展开更多
This paper describes the flow simulation of a dual rotor, three-bladed wind turbine module with a shroud to determine its performance. The parameters that were evaluated are the effects of adding a second rotor, wind ...This paper describes the flow simulation of a dual rotor, three-bladed wind turbine module with a shroud to determine its performance. The parameters that were evaluated are the effects of adding a second rotor, wind speed, distance between the two rotors, the size of the front rotor and the shroud. The results were obtained by using the Solid Works 2015 flow simulation program. Also, the benefits and cost issues for wind generating systems are illustrated.展开更多
文摘Small propeller-type wind turbines have a low Reynolds number,limiting the number of usable airfoil materials.Thus,their design method is not sufBciently established,and their performance is often low.The ultimate goal of this research is to establish high-performance design guidelines and design methods for small propeller-type wind turbines.To that end,we designed two rotors:Rotor A,based on the rotor optimum design method from the blade element momentum theory,and Rotor B,in which the chord length of the tip is extended and the chord length distribution is linearized.We examined performance characteristics and flow fields of the two rotors through wind tunnel experiments and numerical analysis.Our results revealed that the maximum output tip speed ratio of Rotor B shifted lower than that of Rotor A,but the maximum output coefficient increased by approximately 38.7%.Rotors A and B experienced a large-scale separation on the hub side,which extended to the mean in Rotor A.This difference in separation had an impact on the significant decrease in Rotor A's output compared to the design value and the increase in Rotor B's output compared to Rotor A.
文摘During the process of local post-weld heat treatment （ PWHT） , the temperature difference inside the weld overlay is a very influential factor on relieving residual stress. In this paper, a commercial program （ABAQUS） was used to simulate the temperature field in turbine rotor, and the influence of heat treatment parameters on temperature was investigated by finite element method. Weight analysis shows that the holding temperature and heating rate are the main factors affecting on temperature, especially the holding temperature. Besides, two regression equations that reflect the relationship between temperature and heat treatment parameters were fitted with uniform design method. Both the correlation coefficients of the regression equations are up to O. 999 2, and the maximum residual error is only O. 7. The agreement between simulation results and regression results is shown to be excellent. At the end, local heat treatment parameters were optimized using the simplex method.
文摘This paper describes the flow simulation of a dual rotor, three-bladed wind turbine module with a shroud to determine its performance. The parameters that were evaluated are the effects of adding a second rotor, wind speed, distance between the two rotors, the size of the front rotor and the shroud. The results were obtained by using the Solid Works 2015 flow simulation program. Also, the benefits and cost issues for wind generating systems are illustrated.
