Holland Roller Windmill: Investigation and Demonstration of Principles. Final Report

摘要

A horizontal axis wind power machine using a radially positioned spinning cylindrical roller was investigated and a demonstration machine was constructed and operated in the natural wind. Earlier wind machines using the Magnus rotor were reviewed, such as the Flettner Rotor Windmill and the Madaras Rotor Power Plant. Wind tunnel tests and analyses were made. Analyses were made of gyroscopic bending moments on the roller and centrifugal hinge moments acting on the freely hinged trailer. Analyses of applied structural air loads were made of the conventional torsionally restrained airfoil type blade compared to the unconventional blade consisting of roller and free trailer. Criteria for stress analysis of trailer blades were developed. Exploratory wind tunnel tests were made of the downwash patterns around Magnus rotors. The power required to spin them was measured. Combined spinning and whirling of a model horizontal axis roller machine was demonstrated. Tests of blade type models were run. Sections for roller mill blades, consisting of power driven spinning roller and a series of trailers of varying sizes and shapes, were tested. Reynolds number effects on section performance were studied, and broadly suitable types of roller trailer combinations were determined below the critical and above the critical Reynolds. A design was synthesized for a single bladed demonstrator machine, including stress analysis, detail design, construction and assembly. The demonstrator operated satisfactorily in the natural wind. Results indicate that major benefits of this type of machine are virtual elimination of stresses due to gusts and strong winds, and marked reduction of cost per unit of swept disk area. (ERA citation 10:051232)