Diffuser for augmenting a wind turbine

Claim 1

In a diffuser augmented wind turbine, the diffuser comprising: a cylindrical section for positioning the wind turbine therein; a first divergent duct section positioned downstream and outside of said cylindrical section and in spaced-relationship with said cylindrical section whereby a circumferential opening is formed in the space therebetween; a second divergent duct section positioned downstream and outside of said first section and in spaced-relationship with said first section whereby a circumferential opening is formed in the space therebetween; means for connecting said cylindrical section to said first section; means for connecting said first section to said second section; a short collar connected to the outlet of said second section, positioned at least perpendicular to the diffuser axis and extending radially outward into the external flow; wherein the radial length of said collar is from 2% to 5% of the length of the radius of the outlet of said second section; wherein the axial length of the diffuser is equal to the length of the radius of the diffuser inlet; and wherein the ratio of the area of the outlet of said second section to the area of the inlet of said cylindrical section is from 2 to 4.