Optimizing Oar-Based Water Turbine Harvester using Response Surface Methodology for Improving its Hydrokinetic Efficiency

Abstract

In this manuscript, an attempt has been made to evaluate the performance of an indigenously developed oar-based water turbine harvester (OBWTH), with an objective to improve its power coefficient (CP) to the maximum possible extent. In this study, three important design parameters such as which included the ratio between blade length and blade width (bl/bw), the axle length (L), and the blade inclination angle (θ) were optimized. For optimizing, an advance methodology such as response surface methodology was used. For obtaining it, a Central Composite Design (CCD) model was employed and attempts were made to establish empirical relationships between the important three input design parameters with the output efficiency. The significance of the developed empirical relationships was identified with analysis of variance. Using contours and 3-D surface plots, the optimized process conditions for operating the oar-based water turbine harvester were identified, so as to achieve highest possible value of C_p. On conducting validation studies, the results were promising as the actual efficiency was very close with the predicted efficiency. OBWTH performance was the highest, with bl/bw, L, and θ values at 1.8, 185 mm, and 71.7°, respectively. On operating OBWTH under these conditions, highest C_p value of 0.591 was obtained, which was validated to an error percentage lesser than 2%. Interactions were identified and perturbation plots indicated that the performance of OBWTH was more dependent on blade inclination, than the other parameters.