Exercise

1. For a proposed hydroelectric plant, the tailwater and the head water elevation is 160m and 195 m, respectively. If the available flow is 10m3/s and head loss of 4% of available head. What is the water power?

• A. 3261.825 KW

• B. 3678.2 KW

• D. 2425.78 KW

• C. 3296.16 KW

2. In a hydroelectric plant the brake power is 1,850 KW running at 450rpm and net head of 30m. Determine the specific speed of the turbine.

• A. 90.17 rpm

• B. 65.65 rpm

• D. 76.87 rpm

• C. 72.41 rpm

3. In a Francis turbine, the pressure gage leading to the turbine casing reads 400 kPa and center of spiral casing is 3m above the tail race. If the velocity of water entering the turbine is 8m/s, what is the net head of the turbine?

• A. 45 m

• B. 65 m

• C. 54 m

• D. 47 m

4. A pelton type turbine was installed 31m below the head gate of the penstock. The head loss due to friction is 15% of the given elevation. The length of the penstock is 80 m and the coefficient of friction is 0.00093 . Determine the diameter in meters of the penstock and the power output in KW.

• A. 0.422, 820.50

• B. 2.457; 12,345.7

• C. 1.899; 2,348.20

• D. 1.686; 13,128.05

5. A running at 400 rpm has a specific speed of 60 rpm and head available is 41 m. If the rating of each turbine installed is 100 kw, how many turbines must be used?

• A. 2

• B. 4

• C. 5

• D. 7