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Question 1
ప్రశ్న 1
What is the principal energy conversion performed by a hydraulic turbine?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A hydraulic turbine extracts energy from flowing or falling water. The water loses part of its hydraulic energy while passing through the turbine system. This energy produces torque on the turbine runner. The rotating runner transmits mechanical power through the turbine shaft. Therefore Option B is correct.
వివరణ:
Question 2
ప్రశ్న 2
Which statement correctly distinguishes an impulse turbine from a reaction turbine?
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Explanation:
In an impulse turbine, the available pressure head is converted predominantly into jet kinetic energy before the water reaches the runner. The runner is then driven mainly by the change in momentum of the jet. In a reaction turbine, the water enters the runner with pressure as well as kinetic energy. A pressure change occurs while the water passes through the runner passages. Therefore Option B is correct.
వివరణ:
Question 3
ప్రశ్న 3
Which classification correctly describes a Pelton turbine?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A Pelton turbine is an impulse turbine. Water is delivered through one or more nozzles as high-speed jets. Each jet strikes the buckets approximately tangentially to the runner pitch circle. The buckets extract energy mainly through change of jet momentum. Therefore Option A is correct.
వివరణ:
Question 4
ప్రశ్న 4
Which description is most appropriate for a modern Francis turbine?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A Francis turbine is a reaction turbine. Water enters the runner with a significant radial component and turns as it passes through the blade passages. The discharge from the runner is substantially axial in the usual Francis arrangement. It is therefore commonly classified as a mixed-flow reaction turbine. Hence Option C is correct.
వివరణ:
Question 5
ప్రశ్న 5
Which classification correctly describes a Kaplan turbine?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A Kaplan turbine is a reaction turbine designed primarily for relatively low-head, high-discharge applications. The principal flow through its runner is parallel to the shaft axis. It therefore belongs to the axial-flow turbine class. Its adjustable runner blades distinguish the Kaplan design from a simple fixed-blade propeller turbine. Therefore Option B is correct.
వివరణ:
Question 6
ప్రశ్న 6
Which statement correctly relates turbine classification to the principal direction of water flow through the runner?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Hydraulic machines may be classified according to the principal direction of fluid motion through the runner. Radial-flow machines have predominantly radial motion through the runner. Axial-flow machines have fluid motion primarily parallel to the axis. Mixed-flow machines contain important radial and axial components. Therefore Option A is correct.
వివరణ:
Question 7
ప్రశ్న 7
Which statement best distinguishes gross head and net head for a simple hydroelectric turbine installation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Gross head represents the overall hydraulic elevation difference available between the upstream and downstream levels of the installation. Water loses some head while flowing through intakes, waterways, penstocks and other conveyance components. The effective or net head available to the turbine is therefore smaller than the gross head when such losses occur. Turbine performance calculations normally use the appropriate net or effective turbine head. Therefore Option A is correct.
వివరణ:
Question 8
ప్రశ్న 8
A hydroelectric installation has a gross head of 120 m and total hydraulic losses before the turbine of 8 m. What net head is available to the turbine?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The net head is obtained by deducting relevant conveyance losses from the gross head. Here the gross head is 120 m. The hydraulic losses are 8 m. Thus H = 120 - 8 = 112 m. Therefore Option C is correct.
వివరణ:
Question 9
ప్రశ్న 9
Water of density 1000 kg/m³ flows through a turbine at Q = 5.0 m³/s under a net head H = 40 m. What is the hydraulic power supplied by the water? Take g = 9.81 m/s².
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The hydraulic power available from the water is Pw = rho g Q H. Substitution gives Pw = 1000 × 9.81 × 5.0 × 40 W. This equals 1,962,000 W. Expressed in megawatts, the value is 1.962 MW. Therefore Option B is correct.
వివరణ:
Question 10
ప్రశ్న 10
Which expression correctly defines the overall efficiency of a hydraulic turbine when Pshaft is useful shaft output and rho g Q H is the hydraulic power supplied to the turbine?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Overall efficiency compares the useful mechanical output from the turbine shaft with the hydraulic power supplied by the water. The hydraulic input is rho g Q H. The useful output is the shaft power. Therefore eta_o = Pshaft/(rho g Q H). Hence Option B is correct.
వివరణ:
Question 11
ప్రశ్న 11
A turbine delivers 3.20 MW of shaft power while operating with Q = 4.0 m³/s under a net head of 100 m. What is its overall efficiency? Take rho = 1000 kg/m³ and g = 9.81 m/s².
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The water power is rho g Q H = 1000 × 9.81 × 4 × 100. This equals 3.924 MW. Overall efficiency is 3.20/3.924. The result is approximately 0.8155, or 81.5 percent. Therefore Option B is correct.
వివరణ:
Question 12
ప్రశ్న 12
A turbine operates under a net head of 50 m with Q = 6.0 m³/s and has an overall efficiency of 90%. What shaft power does it deliver? Take rho = 1000 kg/m³ and g = 9.81 m/s².
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The hydraulic power input is rho g Q H. Substitution gives 1000 × 9.81 × 6 × 50 = 2.943 MW. Shaft power equals overall efficiency multiplied by hydraulic input power. Thus Pshaft = 0.90 × 2.943 = 2.6487 MW. Therefore Option B is correct.
వివరణ:
Question 13
ప్రశ్న 13
Which definition most appropriately represents hydraulic efficiency of a turbine?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Hydraulic efficiency concerns the effectiveness of energy transfer between the water and the turbine runner. The denominator is the hydraulic power supplied by the water to the turbine or runner under the stated convention. The numerator is the mechanical power developed by the runner through fluid interaction. Mechanical losses in bearings and the shaft system are treated separately by mechanical efficiency. Therefore Option B is correct.
వివరణ:
Question 14
ప్రశ్న 14
The hydraulic power supplied to a turbine runner is 3.00 MW, while the mechanical power developed by the runner is 2.60 MW. What is the hydraulic efficiency?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Hydraulic efficiency is the runner power divided by the hydraulic power supplied. The runner develops 2.60 MW from an available 3.00 MW. Thus eta_h = 2.60/3.00. This equals 0.8667, or approximately 86.7 percent. Therefore Option C is correct.
వివరణ:
Question 15
ప్రశ్న 15
A turbine runner develops 2.50 MW, but only 2.40 MW is available as shaft output because of mechanical losses. What is the mechanical efficiency?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Mechanical efficiency measures the fraction of runner mechanical power that appears as useful shaft power. Therefore eta_m = Pshaft/Prunner. Substitution gives 2.40/2.50. This equals 0.96, or 96 percent. Hence Option C is correct.
వివరణ:
Question 16
ప్రశ్న 16
Using definitions for which hydraulic efficiency is runner power divided by total hydraulic power supplied and mechanical efficiency is shaft power divided by runner power, a turbine has eta_h = 90% and eta_m = 96%. What is its overall efficiency?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Under the stated definitions, overall efficiency equals hydraulic efficiency multiplied by mechanical efficiency. Therefore eta_o = 0.90 × 0.96. This gives 0.864. Expressed as a percentage, the overall efficiency is 86.4 percent. Therefore Option A is correct.
వివరణ:
Question 17
ప్రశ్న 17
A turbine is supplied with 1.20 m³/s of water, but 0.024 m³/s leaks without contributing to useful runner flow. If volumetric efficiency is defined as useful runner discharge divided by supplied discharge, what is the volumetric efficiency?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The useful runner discharge is the supplied discharge minus leakage. Thus Quseful = 1.20 - 0.024 = 1.176 m³/s. Volumetric efficiency is 1.176/1.20. This equals 0.98, or 98 percent. Therefore Option C is correct.
వివరణ:
Question 18
ప్రశ్న 18
Which set correctly defines the conventional unit quantities of a given hydraulic turbine operating at similar conditions under head H?
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Explanation:
For a given turbine operating at homologous conditions, rotational speed varies as the square root of head. Discharge also varies as the square root of head. Power varies as head raised to the three-halves power. The corresponding values reduced to unit head are therefore N/sqrt(H), Q/sqrt(H), and P/H^(3/2). Hence Option B is correct.
వివరణ:
Question 19
ప్రశ్న 19
A turbine runs at 600 rpm under a head of 100 m. What is its unit speed Nu = N/sqrt(H)?
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Explanation:
Unit speed is defined as Nu = N/sqrt(H). The square root of 100 is 10. Therefore Nu = 600/10. The resulting unit speed is 60 rpm under the conventional unit-head representation. Therefore Option B is correct.
వివరణ:
Question 20
ప్రశ్న 20
A turbine operating under H = 64 m has Q = 4.0 m³/s and develops P = 4096 kW. What are its unit discharge Qu and unit power Pu respectively?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Unit discharge is Qu = Q/sqrt(H). Since sqrt(64) = 8, Qu = 4/8 = 0.50 m³/s. Unit power is Pu = P/H^(3/2), and 64^(3/2) = 512. Thus Pu = 4096/512 = 8.0 kW. Therefore Option A is correct.
వివరణ:
Question 21
ప్రశ్న 21
The same turbine operates at corresponding similar conditions with unchanged efficiency. At H1 = 100 m it runs at N1 = 500 rpm, carries Q1 = 5.0 m³/s and develops P1 = 1000 kW. What are N2, Q2 and P2 when the head becomes H2 = 64 m?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For corresponding operation of the same turbine, N and Q vary as sqrt(H), while P varies as H^(3/2). The head ratio H2/H1 is 64/100 = 0.64, whose square root is 0.8. Thus N2 = 500 × 0.8 = 400 rpm and Q2 = 5 × 0.8 = 4.0 m³/s. The power ratio is 0.64^(3/2) = 0.512, giving P2 = 512 kW. Therefore Option A is correct.
వివరణ:
Question 22
ప్రశ్న 22
Under the commonly used metric turbine convention with N in rpm, turbine output power P in kW and net head H in metres, which expression defines turbine specific speed?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Turbine specific speed is conventionally formed from turbine rotational speed, output power and operating head. Under the stated metric convention, Ns = N sqrt(P)/H^(5/4). It may be interpreted as the speed of a geometrically similar turbine corresponding to unit power under unit head according to the chosen convention. Conventional turbine specific speed expressed this way is not itself a dimensionless parameter. Therefore Option A is correct.
వివరణ:
Question 23
ప్రశ్న 23
A turbine runs at 300 rpm and produces 5000 kW under a net head of 100 m. Using Ns = N sqrt(P)/H^(5/4), with P in kW and H in metres, what is its specific speed approximately?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The square root of 5000 is approximately 70.711. The quantity 100^(5/4) is approximately 316.228. Thus Ns = 300 × 70.711/316.228. The result is approximately 67.08. Therefore Option C is correct.
వివరణ:
Question 24
ప్రశ్న 24
Which qualitative relationship between turbine type, specific speed and operating head is generally correct under a consistent turbine-specific-speed convention?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Pelton turbines are particularly suited to relatively high heads and comparatively low discharges. Their conventional turbine specific speeds are therefore relatively low. Francis turbines occupy an intermediate range of head, discharge and specific speed. Kaplan and propeller turbines accommodate large discharges at relatively low heads and generally have higher specific speeds. Therefore Option A is correct.
వివరణ:
Question 25
ప్రశ్న 25
Consider the following statements about hydraulic turbines: I. A Pelton runner is driven by one or more essentially atmospheric-pressure jets. II. Pressure changes through the runner of a reaction turbine such as a Francis or Kaplan turbine. III. Turbine overall efficiency is useful shaft power divided by hydraulic power supplied by the water. IV. Unit speed and unit discharge both vary inversely with sqrt(H) when reducing actual quantities to unit head. Which option is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Statement I correctly describes the basic impulse action of a Pelton turbine. Statement II correctly identifies pressure variation within reaction-turbine runner passages. Statement III is the standard definition of turbine overall efficiency used in this test. Statement IV correctly states Nu = N/sqrt(H) and Qu = Q/sqrt(H) for unit-head quantities. Therefore all four statements are correct and Option D is the valid answer.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: B. Hydraulic energy of water is converted into mechanical shaft energy సమాధానం: B.
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Question 2 ప్రశ్న 2Answer: B. An impulse turbine receives a high-speed jet after pressure energy is converted mainly in a stationary nozzle, whereas a reaction turbine undergoes pressure change within the runner passages సమాధానం: B.
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Question 3 ప్రశ్న 3Answer: A. Tangential-flow impulse turbine సమాధానం: A.
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Question 4 ప్రశ్న 4Answer: C. Mixed-flow reaction turbine, with flow generally having a radial component at entry and becoming substantially axial toward exit సమాధానం: C.
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Question 5 ప్రశ్న 5Answer: B. Axial-flow reaction turbine సమాధానం: B.
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Question 6 ప్రశ్న 6Answer: A. A radial-flow turbine has principally radial runner flow, an axial-flow turbine has principally axial runner flow, and a mixed-flow turbine involves both radial and axial components సమాధానం: A.
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Question 7 ప్రశ్న 7Answer: A. Gross head is the elevation-head difference available between the upstream and downstream water levels, while net head is the head actually available to the turbine after relevant hydraulic conveyance losses are deducted సమాధానం: A.
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Question 8 ప్రశ్న 8Answer: C. 112 m సమాధానం: C.
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Question 9 ప్రశ్న 9Answer: B. 1.962 MW సమాధానం: B.
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Question 10 ప్రశ్న 10Answer: B. eta_o = Pshaft/(rho g Q H) సమాధానం: B.
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Question 11 ప్రశ్న 11Answer: B. 81.5% సమాధానం: B.
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Question 12 ప్రశ్న 12Answer: B. 2.649 MW సమాధానం: B.
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Question 13 ప్రశ్న 13Answer: B. Power transferred from water to the runner divided by the hydraulic power supplied to the runner సమాధానం: B.
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Question 14 ప్రశ్న 14Answer: C. 86.7% సమాధానం: C.
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Question 15 ప్రశ్న 15Answer: C. 96% సమాధానం: C.
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Question 16 ప్రశ్న 16Answer: A. 86.4% సమాధానం: A.
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Question 17 ప్రశ్న 17Answer: C. 98% సమాధానం: C.
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Question 18 ప్రశ్న 18Answer: B. Nu = N/sqrt(H), Qu = Q/sqrt(H) and Pu = P/H^(3/2) సమాధానం: B.
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Question 19 ప్రశ్న 19Answer: B. 60 rpm సమాధానం: B.
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Question 20 ప్రశ్న 20Answer: A. 0.50 m³/s and 8.0 kW సమాధానం: A.
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Question 21 ప్రశ్న 21Answer: A. 400 rpm, 4.0 m³/s and 512 kW సమాధానం: A.
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Question 22 ప్రశ్న 22Answer: A. Ns = N sqrt(P)/H^(5/4) సమాధానం: A.
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Question 23 ప్రశ్న 23Answer: C. 67.1 సమాధానం: C.
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Question 24 ప్రశ్న 24Answer: A. Pelton turbines generally occupy lower specific speeds and higher heads, Francis turbines intermediate values, and Kaplan or propeller turbines higher specific speeds and lower heads సమాధానం: A.
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Question 25 ప్రశ్న 25Answer: D. I, II, III and IV సమాధానం: D.