Refer to the sketches in Fig. 8.13. Consider a wind, upstreamspeed u, passing through the rotor of a turbine, with n bladeseach of length R turning at angular velocity 2. Assume that thismovement disturbs a length d of the airflow, which passes intime tw(i) Calculate the time t, for a blade to move to the position of aprevious blade.(ii) If maximum power is extracted when ttip-speed ratio 2 = (2nR/nd).(iii) If wind tunnel tests on certain model turbines show thatmaximum power extraction occurs when approximately d R/2,show that the maximum power coefficient occurs at à =6 fora two-bladed model, and at 1 = 3 for a four-bladed model.t, show that the(iv) What other general deductions can you make from youranalysis? (a)Rotation(b)DisturbedairstreamUndisturbedairstream(c)Fig. 8.13Turbine speed (frequency) and power capture.a Rotational frequency too slow: some wind passes unperturbed through the actuator disk.b Rotational frequency optimum; whole airstream affected.c Rotational frequency too fast: energy is dissipated in turbulent air motion and vortex shedding.

(A) Power extraction is a function of the time "tb" from one blade to move into the positiin…

movement disturbs a length d of the airflow, which passes in time tw (i) Calculate the time t, for a blade to move to the position of a previous blade. (ii) If maximum power is extracted when t, - t, show that the tip-speed ratio 1=(2TR/nd). M.

movement disturbs a length d of the airflow, which passes in time tw (i) Calculate the time t, for a blade to move to the position of a previous blade. (ii) If maximum power is extracted when t, - t, show that the tip-speed ratio 1=(2TR/nd). M.

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

A scale model of a pump has been tested and the following results obtained. Impeller diameter (D) 110mm Power input (P) 2.5kW Speed (N) 1500 r.p.m. Flow (Q) 14.5 litres/sec Head (H) 17m Efficiency (E) 60% You are to determine the speed and size of a geometrically similar pump which would deliver a flow rate of 25 litres/sec against a 22m resistance head. Determine the power input required by this pump.
Q3- A projectile is fired from point A which is at a height of (1.2 m). The projectile must hit point B on ground, which is 15 m away from A. Find the necessary firing velocity and firing angle for the projectile.
The general energy equation is . For the picture blow, select the simplified the form of the general equation for point 1 and 4____________
Plz do as fast as possible ....!
5.2 The head of water at the inlet of a pipe of length 1 500 m and diameter 400 mm is 50 m. A nozzle of diameter 80 mm at the outlet, is fitted to the pipe. Find the velocity of water at the outlet of the nozzle if ƒ = 0.01 for the pipe.
20. A thrust of 30 kN along the axis of a shaft is taken by a pivot bearing consisting of the frustum of a cone. The outer and inner diameters are 200 mm and 100 mm and the semi-angle of the cone is 60°. The shaft speed is 200 rev/min 0-02. Assuming that the intensity of pressure is uniform over the surface of the bearing, find, from first principles (a) the magnitude of this pros- sure, in N/m²; (b) the power absorbed in friction. (U. Lond.) and (Ans.: 1.272 MN/m²; 1.13 kW)
Consider a helicopter flying in a straight path at a speed of 52 m/s. The the rotor diameter is 10 m and the rotors are moving at 264 RPM (revolutions per minute). What is the maximum rotor tip speed (in m/s). Hint: Note that the rotor will sometime be moving in the direction of the flight path and at other times opposite to the flight path or at an angle to the flight path. The maximum rotor tip speed is generated when the rotor is moving in the direction of the flight path.
The figure represents a front wheel-drive vehicle with a total mass of 1650 kg. Analyze the equilibrium of forces and moments and answer the questions. 620mm 1.8m 1.2m Fig. Front-Wheel-Drive The normal reactions on both set of wheels when the vehicle is at rest on a horizontal road surface are: Nfo = N on front wheels and Nro = N on rear wheels Analyze, with the a proper force diagram and make your determination: the vehicle needs to at a rate of mls2 to achieve equal equal normal forces on both set of rear and front wheel. During the sudden change of speed (acceleration or deceleration, depending on the results informed by your calculation), reactions are respectively N1 = N on rear wheels and NI = N on front wheels. If the same front-wheel-drive vehicle is driven so as to maintain a constant speed up a gradient of 14%, the normal reactions on the the wheel as the vehicle moves up the incline, are respectively, N, = N on rear wheels and Nf. N on front wheels resulting into %3D ratios…
car A round with curve 150m radius with constant velocity 20m/s. at instant car B moving with a velocity of 30m/s and slows down 5m/s^2. find magnitude of velocity as well as acceleration of car B observed from A (Vb/a and aB/A) please show clear work
Find the cam diameter and actual displaced? Volumetric efficiency = 91.87%, N = 1420 rpm, e = 14.67 mm, L = 53.12 mm, Rotor diameter = 77.56 mm, Volume volume Vane pump, %3D displaced = 288.43 cm³-rev1.
13. It is known that the volumetric efficiency of a certain piston pump of unknown displacement is 97%. If the pump delivers 15 I/min at 1200 rpm. What is the displacement of the pump?