The wind data of a site is listed below. The data summarizes the wind speeds and their respective frequencies at the hub height of the turbine described below: Parameters: Turbine rotor diameter: 70.0 m Overall efficiency: 33% Site air density 1.16 kg/m generator disengaged for the input values below 30% of the rated power Generator cutoff low speeds: High speeds: load dumping up to 3 times the rated power

(a) By considering the ratio of the areas A, and A, of Fig. 8.5, show that the optimum power extraction (according to linear momentum theory) per unit of area A, is 8/9 of the incident power in the wind. (b) Prove that the torque produced by a wind turbine rotor of radius R can be expressed as T=(x/2) pC,R³u,? / 2 .

For a 6.25-inch Model 4075 pump operated at 1160 rpm, if 450 GPM of water is to be delivered, what will be the estimated pump head in ft? HEAD IN FEET 30 25 0 0 0 10 O 6 ft 7.25" (184mm) 20 7.00" (178mm). 6.75" (171mm). 6.50" (165mm)] 15 6.25" (159mm). 5 O 16 ft O 20 ft O 12 ft aco® L/SEC 5 OT 10 Model 4075 FI & CI Series 15 -6-6 ⁰ dº 20 ANA 888 778 25 REQUIRED NPSH do 1160 RPM November 1, 2010 K ・dº- [M 90 do 30 8800 81 1HP(.75KW) DeJ kin do 60% 35 do 50 Curve no. 2175 Min. Imp. Dia. 6.25" Size 5 x 4 x 7.0 40 45 3HP(2.2KW), 2HP(1 5KW) 5HP(1 1KW)> CURVES BASED ON CLEAR WATER WITH SPECIFIC GRAVITY OF 1.0 L 75 150 225 300 375 450 525 600 675 FLOW IN GALLONS PER MINUTE NOWONG FEET 15 12 7 6 2 1 NPSH 758 50 5 HEAD IN METERS 45 586888 KPO 60 40 20 10 LO HEAD IN KILOPASCALS