Study on hydrodynamics of the vertical-axis turbine with variable radius

摘要

In this paper,a novel conception of Variable Radius Vertical-Axis Turbine (VRVAT) has been proposed for the design of tidal current power generator turbine.Different from conventional Vertical-Axis Turbine (VAT),the radius of VRVAT varies along with azimuthal angle.The investigation on hydrodynamic performance of the proposed turbine has been made in details by using numerical program developed based on multiple streamtube theory.Firstly,mathematical formulas have been derived for the new type turbine.Then hydrodynamic coefficients,including lift,drag,torque and thrust have been analyzed and compared with conventional VAT.The numerical investigations release that the new type tidal power turbine really generates much more torque.For instance,the maximum value of Torque for VRVAT (oval trajectory with a =1.6b when the tip speed ratio is 3.0) is nearly 2.6 times the value of conventional VAT.Although more work should be done to fulfill the method of variable radius,the bright future of VRVAT can be predicted.