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A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.
Correct answer is 'Range: 125 to 135'. Can you explain this answer?
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A single jet Pelton turbine is required to drive a generator to devel...
Mechanical power output of the turbine
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= Electrical power output / Generator efficiency
= 10 / 0.95 = 10.53 MW
Pelton wheel efficiency 
Where Q is the flow rate through the turbine.
Then, Q = 
= 
= 1.62m3
= = 1.62m3If d1 is the diameter of the jet, we can write
Where Cv is the coefficient of velocity, then
Which given d1 = 0.132m = 132 mm
Most Upvoted Answer
A single jet Pelton turbine is required to drive a generator to devel...
Given data:
Available head at the nozzle = 762 m
Electric generator efficiency = 95%
Pelton wheel efficiency = 87%
Coefficient of velocity for nozzle = 0.97
Mean bucket velocity = 0.46 of jet velocity
Outlet angle of the buckets = 15°
Friction of the bucket reduces the relative velocity by 15%
Ratio of mean bucket circle diameter to the jet diameter ≥ 10
Required power output = 10 MW
To find: Diameter of the jet (in mm)
Solution:
Step 1: Calculation of water flow rate (Q)
Power output = ρQgHη_genη_pelton
Where,
ρ = Density of water = 1000 kg/m³
g = Acceleration due to gravity = 9.81 m/s²
H = Available head at the nozzle = 762 m
η_gen = Electric generator efficiency = 95% = 0.95
η_pelton = Pelton wheel efficiency = 87% = 0.87
Power output = 10 MW = 10×10⁶ W
∴ Q = Power output / (ρgHη_genη_pelton) = (10×10⁶) / (1000×9.81×762×0.95×0.87) = 143.55 m³/s
Step 2: Calculation of jet velocity (Vj)
Vj = √(2gH)
= √(2×9.81×762)
= 109.84 m/s
Step 3: Calculation of actual velocity of water (Va)
Va = Vj × Cv
Where,
Cv = Coefficient of velocity for nozzle = 0.97
∴ Va = 109.84 × 0.97 = 106.47 m/s
Step 4: Calculation of mean bucket circle diameter (Dm)
Dm/Dj ≥ 10
Where,
Dj = Diameter of the jet
∴ Dm ≥ 10×Dj
Let's assume Dm = 15×Dj
Step 5: Calculation of relative velocity of water (Vr)
Vr = Va × sin(15°)
= 106.47 × sin(15°)
= 28.07 m/s
Step 6: Calculation of bucket speed (Ub)
Ub = Vm / sin(15°)
Where,
Vm = Mean bucket velocity = 0.46 of jet velocity
∴ Vm = 0.46 × 106.47 = 49.01 m/s
∴ Ub = 49.01 / sin(15°) = 189.57 m/s
Step 7: Calculation of speed ratio (σ)
σ = Ub / Vr
= 189.57 / 28.07
= 6.75
Step 8: Calculation of bucket friction velocity (Uf)
Uf = Vr × 0.15
= 28.07 × 0.15
= 4.21 m/s
Step 9: Calculation of effective velocity of water (Ve)
Ve = Va - Uf
= 106.47 - 4.21
= 102.26 m/s
Step 10: Calculation of discharge (Q)
Q = Av × Ve
Where,
Av = Area of the
Available head at the nozzle = 762 m
Electric generator efficiency = 95%
Pelton wheel efficiency = 87%
Coefficient of velocity for nozzle = 0.97
Mean bucket velocity = 0.46 of jet velocity
Outlet angle of the buckets = 15°
Friction of the bucket reduces the relative velocity by 15%
Ratio of mean bucket circle diameter to the jet diameter ≥ 10
Required power output = 10 MW
To find: Diameter of the jet (in mm)
Solution:
Step 1: Calculation of water flow rate (Q)
Power output = ρQgHη_genη_pelton
Where,
ρ = Density of water = 1000 kg/m³
g = Acceleration due to gravity = 9.81 m/s²
H = Available head at the nozzle = 762 m
η_gen = Electric generator efficiency = 95% = 0.95
η_pelton = Pelton wheel efficiency = 87% = 0.87
Power output = 10 MW = 10×10⁶ W
∴ Q = Power output / (ρgHη_genη_pelton) = (10×10⁶) / (1000×9.81×762×0.95×0.87) = 143.55 m³/s
Step 2: Calculation of jet velocity (Vj)
Vj = √(2gH)
= √(2×9.81×762)
= 109.84 m/s
Step 3: Calculation of actual velocity of water (Va)
Va = Vj × Cv
Where,
Cv = Coefficient of velocity for nozzle = 0.97
∴ Va = 109.84 × 0.97 = 106.47 m/s
Step 4: Calculation of mean bucket circle diameter (Dm)
Dm/Dj ≥ 10
Where,
Dj = Diameter of the jet
∴ Dm ≥ 10×Dj
Let's assume Dm = 15×Dj
Step 5: Calculation of relative velocity of water (Vr)
Vr = Va × sin(15°)
= 106.47 × sin(15°)
= 28.07 m/s
Step 6: Calculation of bucket speed (Ub)
Ub = Vm / sin(15°)
Where,
Vm = Mean bucket velocity = 0.46 of jet velocity
∴ Vm = 0.46 × 106.47 = 49.01 m/s
∴ Ub = 49.01 / sin(15°) = 189.57 m/s
Step 7: Calculation of speed ratio (σ)
σ = Ub / Vr
= 189.57 / 28.07
= 6.75
Step 8: Calculation of bucket friction velocity (Uf)
Uf = Vr × 0.15
= 28.07 × 0.15
= 4.21 m/s
Step 9: Calculation of effective velocity of water (Ve)
Ve = Va - Uf
= 106.47 - 4.21
= 102.26 m/s
Step 10: Calculation of discharge (Q)
Q = Av × Ve
Where,
Av = Area of the
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A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer?
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A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer? for Civil Engineering (CE) 2024 is part of Civil Engineering (CE) preparation. The Question and answers have been prepared according to the Civil Engineering (CE) exam syllabus. Information about A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer? covers all topics & solutions for Civil Engineering (CE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer?.
A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer? for Civil Engineering (CE) 2024 is part of Civil Engineering (CE) preparation. The Question and answers have been prepared according to the Civil Engineering (CE) exam syllabus. Information about A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer? covers all topics & solutions for Civil Engineering (CE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer?.
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A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer?, a detailed solution for A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer? has been provided alongside types of A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice A single jet Pelton turbine is required to drive a generator to develop 10 MW. The available head at the nozzle is 762 m. Assuming electric generator efficiency 95%, Pelton wheel efficiency 87%, coefficient of velocity for nozzle 0.97, mean bucket velocity 0.46 of jet velocity, outlet angle of the buckets 15° and the friction of the bucket reduces the relative velocity by 15%, find the diameter of the jet (in mm), if the ratio of mean bucket circle diameter to the jet diameter is not to be less than 10.Correct answer is 'Range: 125 to 135'. Can you explain this answer? tests, examples and also practice Civil Engineering (CE) tests.
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