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A hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:
(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter
(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7
- a)6.44 m and 7.22 m below tail race respectively
- b)2.25 m and 11.6 m below tail race respectively
- c)6.44 m and 3.96 m below tail race respectively
- d)2.25 m and 7.22 m below tail race respectively
Correct answer is option 'B'. Can you explain this answer?
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Verified Answer
A hydro-electric power station required to generate 60,000 kW at 50 c...
Power at the shaft, P = wQH × ηo
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∴ Discharge through the turbine,
⇒ hs = −3.96 m
The negative sign suggests that the turbine is to be installed below the tail race level. Kinetic energy head at draft tube inlet,
Hence turbine should be placed (7.22 + 3.96) = 11.6 m below the tail race level.
Most Upvoted Answer
A hydro-electric power station required to generate 60,000 kW at 50 c...
Power at the shaft, P = wQH × ηo
∴ Discharge through the turbine,
⇒ hs = −3.96 m
The negative sign suggests that the turbine is to be installed below the tail race level. Kinetic energy head at draft tube inlet,
Hence turbine should be placed (7.22 + 3.96) = 11.6 m below the tail race level.
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Community Answer
A hydro-electric power station required to generate 60,000 kW at 50 c...
To calculate the hub diameter of the Kaplan turbine and the maximum safe elevation of the runner, we need to use the specific speed and other given parameters.
(i) Calculation of Hub Diameter:
Given:
Power output (P) = 60,000 kW
Frequency (f) = 50 cycles/sec
Available head (H) = 20 m
Specific speed (N_s) = 600 units
Flow ratio (α) = 0.6
Hub diameter of the wheel (D_h) = 0.35 times the outside diameter (D_o)
Using the formula for specific speed:
N_s = N * √(P / H)
where N is the speed of the turbine in RPM.
Rearranging the formula, we get:
N = N_s * √(H / P)
Substituting the given values:
N = 600 * √(20 / 60,000) = 6.928 RPM (approximately)
The specific speed of a Kaplan turbine is given by:
N_s = (N * √(P / H)) / α
Substituting the given values, we can rearrange the formula to solve for the outside diameter (D_o):
D_o = (N * √(P / H)) / (α * N_s)
Substituting the values:
D_o = (6.928 * √(60,000 / 20)) / (0.6 * 600) = 0.962 m (approximately)
Finally, we can calculate the hub diameter (D_h):
D_h = 0.35 * D_o = 0.35 * 0.962 = 0.3377 m (approximately)
(ii) Calculation of Maximum Safe Elevation:
Given:
Vapour pressure (P_v) = 0.26 m of water
Critical value of Thomas’s cavitation factor (σ_c) = 0.7
The maximum safe elevation of the runner can be calculated using the formula:
H_s = H - P_v * σ_c
Substituting the given values:
H_s = 20 - 0.26 * 0.7 = 19.818 m (approximately)
Therefore, the hub diameter of the turbine is approximately 0.3377 m and the maximum safe elevation of the runner to avoid cavitation is approximately 19.818 m below the tail race.
Hence, the correct answer is option B: 2.25 m and 11.6 m below the tail race respectively.
(i) Calculation of Hub Diameter:
Given:
Power output (P) = 60,000 kW
Frequency (f) = 50 cycles/sec
Available head (H) = 20 m
Specific speed (N_s) = 600 units
Flow ratio (α) = 0.6
Hub diameter of the wheel (D_h) = 0.35 times the outside diameter (D_o)
Using the formula for specific speed:
N_s = N * √(P / H)
where N is the speed of the turbine in RPM.
Rearranging the formula, we get:
N = N_s * √(H / P)
Substituting the given values:
N = 600 * √(20 / 60,000) = 6.928 RPM (approximately)
The specific speed of a Kaplan turbine is given by:
N_s = (N * √(P / H)) / α
Substituting the given values, we can rearrange the formula to solve for the outside diameter (D_o):
D_o = (N * √(P / H)) / (α * N_s)
Substituting the values:
D_o = (6.928 * √(60,000 / 20)) / (0.6 * 600) = 0.962 m (approximately)
Finally, we can calculate the hub diameter (D_h):
D_h = 0.35 * D_o = 0.35 * 0.962 = 0.3377 m (approximately)
(ii) Calculation of Maximum Safe Elevation:
Given:
Vapour pressure (P_v) = 0.26 m of water
Critical value of Thomas’s cavitation factor (σ_c) = 0.7
The maximum safe elevation of the runner can be calculated using the formula:
H_s = H - P_v * σ_c
Substituting the given values:
H_s = 20 - 0.26 * 0.7 = 19.818 m (approximately)
Therefore, the hub diameter of the turbine is approximately 0.3377 m and the maximum safe elevation of the runner to avoid cavitation is approximately 19.818 m below the tail race.
Hence, the correct answer is option B: 2.25 m and 11.6 m below the tail race respectively.
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A hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. Can you explain this answer?
Question Description
A hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. 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 hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. 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 hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. Can you explain this answer?.
A hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. 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 hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. 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 hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. Can you explain this answer?.
Solutions for A hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for Civil Engineering (CE).
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A hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. Can you explain this answer?, a detailed solution for A hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. Can you explain this answer? has been provided alongside types of A hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice A hydro-electric power station required to generate 60,000 kW at 50 cycle frequency and at the available head of 20 m suggests the use of Kaplan turbine for which specific speed is 600 units. Make calculations for:(i) hub diameter of the turbine assuming flow ratio 0.6 and that hub diameter of the wheel is 0.35 times the outside diameter(ii) maximum safe elevation of runner to avoid cavitation taking vapour pressure 0.26 m of water and critical value of Thomas’s cavitation factor 0.7a) 6.44 m and 7.22 m below tail race respectivelyb) 2.25 m and 11.6 m below tail race respectivelyc) 6.44 m and 3.96 m below tail race respectivelyd) 2.25 m and 7.22 m below tail race respectivelyCorrect answer is option 'B'. Can you explain this answer? tests, examples and also practice Civil Engineering (CE) tests.
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