Improvement of self-starting and power extraction performance of an H-type vertical-axis hydrokinetic turbine by partial deflection of its blades

In this study, a new method was proposed to improve both the self -start and energy -harvesting capabilities of a straight -bladed H -type Darrieus vertical -axis hydrokinetic turbine (VAHT) via partial deflection of its blades including the leading and trailing edges. First, a detailed two-dimensional numerical simulation was performed to investigate the self-starting process of the VAHT equipped with the deflectable leading -edge blades based on moving overlapping mesh methodology. The results suggest that the blade surface flow field can be considerably improved by actively controlling the deflection of the blade leading edge, enabling the turbine to complete the self-starting process and stabilize the output torque more rapidly. Compared with conventional hydrokinetic turbines, the hydrokinetic turbine with blades having a deflectable leading edge can reach a stable state after one rotation cycle since it starts to rotate. Therefore, the time required for the self-starting process was significantly reduced. Second, the power performance of the VAHT having blades with deflectable leading and trailing edges was numerically examined, and the results showed that the power output of the turbine under different operating conditions could be substantially promoted by combining the deflection of the leading and trailing edges of its blades, indicating the considerable potential for practical applications.