No abstract

The paper deals with the detailed aerodynamic design and performance as well as the calculation of the energy-output of a three-bladed propellertype rotor of a 10 to 20 kW wind machine. The aimed-at wind machine is designed to best suit manufacturing technologies and wind energy climatology of Egypt. The in-hand detailed information, obtained through a comprehensive survey and evaluation process reported by the present author in two preceding published works, in addition to the results of a series of computer-runs carried-out to evaluate the performance of a number of internationally-successful wind-machine rotors, have been used to determine the geometric and the aerodynamic parameters of the rotor-design Al. The rotor is designed to operate, when adjusted at the determined performance-setting (speed of rotation & blade pitching angle), at four possible options having rated power of 10, 12.5, 16 and 20 kW; each of them best suits a corresponding annual-average wind-speed level. The computer code used in the design is an addition to the Rockwell-International program to give it the full advantages of use on a modern personal computer.

The paper is aiming at exploring the area of pitch control. type of regulation used in small propeller-type wind machines. To cover the lack of published information about the real design criteria of such type of regulation, this work is carried out to develop the pertaining theoretical database. The paper investigates the dynamic performance of the centrifugally-activated pitch control mechanisms widely-used in wind machines. A typical pitching mechanism is chosen to be the subject of analysis; namely the crank-slider-crank mechanism which is centrifugally-activated by hub-mounted fly weights. The kinematic and dynamic characteristics of the candidate system are fully analysed. The results are presented in a group of charts in terms of the system dimensionless design-parameters, best suiting the engineers for design purposes.

Flutter constraint, applicable to aircraft conceptual design, is constructed using response surface methodology. It is presented by the critical flutter speed, as a function of wing torsion stiffness, root chord, sweep, mass ratio, taper ratio, aspect ratio, center of gravity location and radius of gyration. The constraint to is a quadratic response surface polynomial. The D-optimal design is used to find the best combinations of design points required to determine the function coefficients. 'The Regier number criterion is used to calculate the critical flutter speed at these design points. Analysis of variance is used to remove the unreliable terms from the function. To match the Regier number criterion, two constraint functions suitable for subsonic aircraft with traditional wing are constructed. The first one is applicable to aircraft with low sweepback wing while the second one is applicable to aircraft with moderate sweepback wing. As a case study, the constraint function is applied within the conceptual design of a subsonic aircraft leading to a considerable weight saving.

No abstract