| The fixed-pitch straight-bladed vertical-axis tidal turbines (SB-VATTs) have many merits such as their systems are stabilized, the optimal structures of blades are untwisted, making them relatively easy to manufacture or fabrication, it can realize high power, large diameter and low cost. Therefore, SB-VATTs are highly concerned in recent years. But compared with variable pitch bladed VATTs, the fixed pitch bladed SB-VATTs may fail the self-starting torque and have low power coefficient Cp when the flow speed is low. So how to enhance the self-starting torque and how to obtain considerable power coefficient of SB-VATTs are the pop problems nowadays. This paper uses for reference the guide-vanes principle of potential energy turbines, numerically simulates the hydrodynamic performance of SB-VATTs with guide vanes installed the surrounding area by using viscous Computation Fluid Dynamics method and Fluent software. This paper may provide useful advice for further investigation.Firstly, the basic knowledge about guide vanes is introduced, the cases of SB-VATTs with guide vanes are designed, and the hydrodynamic performances of three-dimensional fin stabilizer profile under steady movement are simulated, which were compared with the experimental data to improve numerical stimulation method's reliability.Then, we use the CFD method to calculate the self-starting torque of SB-VATTs with guide vanes at different flow speeds, and compare with which of open water conditions. We analyse the complicated causes of influencing SB-VATTs self-starting performance, discuss the effect of guide vanes for enhancing the operating performance of tidal turbine.At last, we establish the sliding mesh model to calculate the transient hydrodynamic performances of SB-VATTs with guide vanes, and we preliminary analyse the effect of guide vanes for the SB-VATTs at different setting angle, different distance among the cascades and different distance from cascade to the tracing circle of tidal turbines.
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