Articles for november 2016

KD 485 reviewed

Report KD 485 describes five safety systems for which the rotor is turned out of the wind. For all systems it is assumed that the rotor has a certain eccentricity e. In stead of an eccentrically placed rotor, one may also use an auxiliary vane. This use is explained in chapter 4 of KD 584 for a flat vane blade with an aspect ratio of 2 : 1. The use of a new vane type which is made out of a vertical cylinder is added to chapter 4. A vertical cylinder has almost the same characteristics as an eccentrically placed rotor and is therefore a better alternative than a flat vane blade.

KD 616 added

The new report KD 616 has as tittle:”Translation of parts of report R 343 D of June 1978 from Dutch into English. R 343 D gives wind tunnel measurements for a rotor with tapered blades made out of a cylinder”. Report R 343 D is one of the earliest reports which I wrote when I was working at the Wind Energy Group of the University of Technology Eindhoven. It is probably the only report in which wind tunnel measurements are given for a fast running 2-bladed rotor for which the curved sheet airfoil is used with increasing chord and camber at decreasing radius. All my VIRYA windmills with blades with curved sheet airfoils have a constant chord because such blades are easier to manufacture. But tapered blades have a higher maximum Cp and look better and it might be worth the effort to design a more complicated blade press if the rotor is made in larg series.

KD 582 added, KD 614 reviewed

Report KD 582 has been made public. This report describes an alternative tubular tower for the VIRYA-4.2 and the VIRYA-4.6B2. It contains strength calculations and calculations of the natural frequencies. Chapter 10 has been added to report KD 614. In this chapter the head geometry of the VIRYA-5 windmill is checked.

Sequence of KD-reports for self-study

At the menu KD-reports, a note with the title “Sequence of KD-reports for self-study” is added  just below the list in which all public KD-reports are specified. If someone wants to design a windmill and if he wants to gain the knowledge which is required to do so, it is advised to read the reports in the sequence as given in this note.