Ideal Wind Turbine Research Articles

Vortex theory of the ideal wind turbine

Based on the concepts outlined by Joukowsky nearly a century ago, an analytical aerodynamic optimization model is developed for rotors with a finite number of blades and constant circulation distribution. In the paper we show the basics of the new model and compare its efficiency with results for rotors designed using the optimization model of Betz.

An ideal wind turbine with a finite number of blades

An ideal wind turbine with a finite number of blades

Optimum operating regimes for the ideal wind turbine

We here present new results on the classical work of the optimum rotor. The emphasis is put vortex theory for which we have developed a new analytical method to determine the loading on an optimum win turbine rotor. The introduction of the work is a repetition of results using momentum theory. This is included in order to validate and compare the new model at simplified situations, such as a rotor operating without swirl and/or a rotor with infinite many blades.

The Lanchester–Betz–Joukowsky limit

AbstractThe maximum efficiency of an ideal wind turbine rotor is well known as the ‘Betz limit’, named after the German scientist that formulated this maximum in 1920. In 1976, Bergey showed that the British scientist Lanchester derived the same maximum already in 1915. Betz and Lanchester were representatives of leading aerodynamic research schools in the first decades of the previous century. A study of early Russian publications on rotor aerodynamics now shows that the Russian aerodynamic school also produced the same result; its leader Joukowsky derived the maximum efficiency for an ideal wind turbine in 1920, the same year as Betz did. Consequently, in order to honour all, this ideal efficiency should be named the ‘Lanchester‐Betz‐Joukowsky limit’ in scientific writing. The well‐established and convenient name Betz limit is to be considered an easy abbreviation of this full name. Copyright © 2007 John Wiley & Sons, Ltd.

An analytical expression for the power coefficient of an ideal horizontal-axis wind turbine

The paper shows that an analytical evaluation of the power coefficient C{sub p} for an ideal horizontal-axis wind turbine can be made via an expression giving the direct relationship of C{sub p} and the axial induction factor a. The results obtained agree closely with those obtained numerically from the usual integral expression involving several variables. (Author).

Experiments With a Diffuser-Augmented Model Wind Turbine

The initial stages of the experimental development of the diffuser-augmented wind turbine (DAWT) employed various screen meshes to simulate the energy extraction mechanisms of a wind turbine. In this investigation in a 2 × 3 m wind tunnel, a three-bladed constant chord, untwisted turbine model was incorporated into a DAWT model. The objectives were to add real turbine characteristics such as swirl, and centerbodies effects, to the flow. Although this turbine model was not well matched to the diffuser, the model DAWT system increased the power output by more than four times that of the model turbine operating as a conventional wind energy conversion system; more than 3.4 times the power potential of an ideal wind turbine was measured.

The shrouded aerogenerator

Experimental studies have been performed on a shrouded aerogenerator. The device tested will produce about twice the output power obtainable from an ideal wind turbine working under the same freestream conditions but without a duct. The aerogenerator does not require a driving mechanism that will keep it parallel to the free-stream direction. A simple, two-stage turbine with fixed blade geometry will provide the expected power output over a fairly wide range of free-stream velocities and rotational speeds.