In this paper, hydrodynamic analysis of vertical axis tidal turbine （both fixed pitch ＆ variable pitch） is numerically analyzed. Two-dimensional numerical modeling ＆ simulation of the unsteady flow through the bla...In this paper, hydrodynamic analysis of vertical axis tidal turbine （both fixed pitch ＆ variable pitch） is numerically analyzed. Two-dimensional numerical modeling ＆ simulation of the unsteady flow through the blades of the turbine is performed using ANSYS CFX, hereafter CFX, which is based on a Reynolds-Averaged Navier-Stokes （RANS） model. A transient simulation is done for fixed pitch and variable pitch vertical axis tidal turbine using a Shear Stress Transport turbulence （SST） scheme. Main hydrodynamic parameters like torque T, combined moment CM, coefficients of performance Cp and coefficient of torque Cr, etc. are investigated. The modeling and meshing of turbine rotor is performed in ICEM-CFD. Moreover, the difference in meshing schemes between fixed pitch and variable pitch is also mentioned. Mesh motion option is employed for variable pitch turbine. This article is one part of the ongoing research on tm＇bine design and developments. The numerical simulation results are validated with well reputed analytical results performed by Edinburgh Design Ltd. The article concludes with a parametric study of turbine performance, comparison between fixed and variable pitch operation for a four-bladed turbine. It is found that for variable pitch we get maximum Ce and peak power at smaller revolution per minute N and tip sped ratio 2.展开更多
In order to study the dynamic characteristics of automobile with a CVT system, a bond graph analysis model of continuously variable transmission is established. On the base of the simulation state space equations that...In order to study the dynamic characteristics of automobile with a CVT system, a bond graph analysis model of continuously variable transmission is established. On the base of the simulation state space equations that are established with bond graph theory, a fuzzy control strategy with an expert system of starting process has been introduced. Considering uncertain system parameters and exterior resistance disturbing , the effect of the profile of membership function and the defuzzification algorithm on the capacity of the fuzzy controller has been studied. The result of simulation proves that the proposed fuzzy controller is effective and feasible. Such controller has been employed in the actual control and has proved practicable. The study lays a foundation for design of the fuzzy controller for automobile with a CVT system.展开更多
基金financially supported by National "863" Program (Grant No.2007AA05Z450, No. 200805040)National S&T Program (No.2008BAA15B04)+2 种基金2010 National Ocean Special Funds(No.ZJME2010GC01, No. ZJME2010CY01, No.GHME2010GC02)supported by the Fundamental Research Funds of the Universities(No.HEUCF130105)supported by "111 project" foundation(No. B07019) from State Administration of Foreign Experts Affairs of China and Ministry of Education of China
文摘In this paper, hydrodynamic analysis of vertical axis tidal turbine （both fixed pitch ＆ variable pitch） is numerically analyzed. Two-dimensional numerical modeling ＆ simulation of the unsteady flow through the blades of the turbine is performed using ANSYS CFX, hereafter CFX, which is based on a Reynolds-Averaged Navier-Stokes （RANS） model. A transient simulation is done for fixed pitch and variable pitch vertical axis tidal turbine using a Shear Stress Transport turbulence （SST） scheme. Main hydrodynamic parameters like torque T, combined moment CM, coefficients of performance Cp and coefficient of torque Cr, etc. are investigated. The modeling and meshing of turbine rotor is performed in ICEM-CFD. Moreover, the difference in meshing schemes between fixed pitch and variable pitch is also mentioned. Mesh motion option is employed for variable pitch turbine. This article is one part of the ongoing research on tm＇bine design and developments. The numerical simulation results are validated with well reputed analytical results performed by Edinburgh Design Ltd. The article concludes with a parametric study of turbine performance, comparison between fixed and variable pitch operation for a four-bladed turbine. It is found that for variable pitch we get maximum Ce and peak power at smaller revolution per minute N and tip sped ratio 2.
基金Funded by the Ford-NSFC Foundation of China (No.50122151).
文摘In order to study the dynamic characteristics of automobile with a CVT system, a bond graph analysis model of continuously variable transmission is established. On the base of the simulation state space equations that are established with bond graph theory, a fuzzy control strategy with an expert system of starting process has been introduced. Considering uncertain system parameters and exterior resistance disturbing , the effect of the profile of membership function and the defuzzification algorithm on the capacity of the fuzzy controller has been studied. The result of simulation proves that the proposed fuzzy controller is effective and feasible. Such controller has been employed in the actual control and has proved practicable. The study lays a foundation for design of the fuzzy controller for automobile with a CVT system.
