Performance optimization of a modified Wells turbine for wave energy conversion

Abstract

The Wells axial turbine is one of the most prevalent wave energy conversion turbines. The current study addresses the optimization of the power produced by a Wells turbine utilizing a response surface optimization approach based on computational fluid dynamics (CFD). The response surface optimization library in the ANSYS software was used in this study. The tip treatment strategy was utilized to improve the performance of the Wells turbine. Four tip groove design parameters were used as input parameters in the optimization process. The main objective of the optimization process was to maximize the modified Wells turbine torque coefficient at a flow coefficient (φ). The results indicated that the modified Wells turbine's average and maximum torque coefficients (CTav and CTmax, respectively) were improved by 18.01% and 49.19%, respectively. The modified turbine's operating range (OR) was improved by 20% compared to a baseline turbine. The modified Wells turbine's efficiency was increased by 18.23% and 67.98% at flow coefficients (φ) of 0.225 and 0.250, respectively. The optimum design improved the power produced by 41.6%. According to comprehensive flow analysis, the best tip treatment design decreased the separation flow zone close to the blade tip and delayed the stall onset point.