Fluid flow energy converter

Abstract

Energy is extracted from a free-stream fluid flow of wind or water by means of a multi-turn helicoid structure with a relatively small pitch angle. The axis of the structure about which the helicoid turns is making an angle with the flow vector in the order of or slightly larger that the pitch angle. Several such helicoid structures are combined with their radii overlapping, for the most effective interception of a certain cross sectional area of the fluid flow. Mile-long helicoid walls may be erected in this fashion. Using groups of helicoids which alternately turn clockwise and counter-clockwise all gyroscopic forces, which appear when the structures are turned to follow changes in the direction of the flow, are internally balanced. An omni-directional structure is also described which need not be turned when the flow direction changes. It is obtained by adding flow-diverters surrounding a helicoid structure with vertical axis. It is shown how various types of light and thin but rigid helicoid surfaces can be constructed from sheet materials without requiring plastic deformation because of the small pitch angles, as here employed.