Small Wind Turbines: Analysis, Design, and Application (Green Energy and Technology)
David Wood
Language: English
Pages: 272
ISBN: 1849961743
Format: PDF / Kindle (mobi) / ePub
Small Wind Turbines provides a thorough grounding in analysing, designing, building, and installing a small wind turbine. Small turbines are introduced by emphasising their differences from large ones and nearly all the analysis and design examples refer to small turbines.
The accompanying software includes MATLAB® programs for power production and starting performance, as well as programs for detailed multi-objective optimisation of blade design. A spreadsheet is also given to help readers apply the simple load model of the IEC standard for small wind turbine safety. Small Wind Turbines represents the distilled outcome of over twenty years experience in fundamental research, design and installation, and field testing of small wind turbines.
Small Wind Turbines is a suitable reference for student projects and detailed design studies, and also provides important background material for engineers and others using small wind turbines for remote power and distributed generation applications.
Clausen PD, Wood DH (2000) Recent advances in small wind turbine technology. Wind Eng 24:189–201 16. Brøndsted P, Lilholt H, Lystrup A (2005) Composite materials for wind power turbine blades. Ann Rev Mater Res 35:505–538 17. Wright AD, Wood DH (2004) The starting and low wind speed behaviour of a small horizontal axis wind turbine. J Wind Eng Ind Aerodyn 92:1265–1279 18. Wood DH (2010) Small wind turbines for remote power and distributed generation. Wind Eng 34:241–254 19. Kentfield JAC (1996)
approximation to the variations in velocity, chord, and twist along a blade. Experience shows that typical performance analyses can be done accurately with between 10 and 20 blade elements. The conservation equations for these streamtubes are easily-recognised generalisations of those derived in Chap. 2 for mass, axial and angular momentum, and energy. The velocity and pressure within each streamtube do not vary with radius but may vary from one streamtube to the next. Each streamtube intersects
of range. Figure 5.2a shows the predicted and measured CP, and Fig. 5.2b shows the corresponding thrust coefficient. It must be noted that a was outside (higher than) the tabulated range for some blade elements for k B 7 so those results must be treated with caution. Some specific results for k = 8, 10, and 12 are shown in Figs. 5.3, 5.4, 5.5 and 5.6 inclusive. Note that the torque and thrust contributions from blade elements, given in the highlighted output below and plotted in Figs. 5.5 and
against two quite different situations. Furling is routinely required when the turbine is producing full power and the wind speed increases, where from Chaps. 2 and 5, the thrust coefficient is close to unity. Much less often, the turbine will lose its load and the blades accelerate to the runaway state where the thrust coefficient may be significantly higher, judging from Fig. 2.2. 162 8 The Unsteady Aerodynamics of Turbine Yaw and Over-Speed Protection Fig. 8.14 Close up of 500 W turbine
fatigue damage. IEC 61400-2 states that this is to be done using Miner’s rule. The damage calculation is as follows32: Damage ¼ X i n Ài Á Ncycles cf cm si 1 ð9:32Þ where ni is the number of fatigue cycles in bin i of the characteristic load spectrum, si is the stress level of the fatigue cycles including effects from both mean and cyclic stress levels, Ncycles, is the number of cycles to failure as a function of the stress, which in turn is calculated using the same combined safety factor