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All questions of Fluid Machinery for Mechanical Engineering Exam
What is the value of the angle (degree) between stream lines and equipotential lines at the point of intersection in the flow net?- a)0°
- b)45°
- c)60°
- d)90°
Correct answer is option 'D'. Can you explain this answer?
What is the value of the angle (degree) between stream lines and equipotential lines at the point of intersection in the flow net?
a)
0°
b)
45°
c)
60°
d)
90°
 | Avinash Sharma answered |
Angle between stream lines and equipotential lines at a point of intersection in the flow net is always intersect at 90°
Which of the following instrument is used for measuring the discharge?- a)Current meter
- b)manometer
- c)Vane anemometer
- d)Venturimeter
Correct answer is option 'D'. Can you explain this answer?
Which of the following instrument is used for measuring the discharge?
a)
Current meter
b)
manometer
c)
Vane anemometer
d)
Venturimeter
 | Lavanya Menon answered |
Venturimeter: Used to measure discharge in the pipe flow.
Manometer: Measure low, medium and high gauge as well as vacuum pressure of liquids and gases both.
Current meter: Used to measure the velocity of water in the rivers
Vane anemometer: Used for measuring the velocity and volumetric flow rate on air grills in residential buildings and utility.
The standard sea level atmospheric pressure is equivalent to- a)10.2 m of freshwater of density (ρ) = 998 kg/m3
- b)10.1 m of saline water of density (ρ) = 1025 kg/m3
- c)12.5 m of kerosene of density (ρ) = 800 kg/m3
- d)
- 6.4 m of carbon tetrachloride of density (ρ) = 1590 kg/m3
Correct answer is option 'B'. Can you explain this answer?
The standard sea level atmospheric pressure is equivalent to
a)
10.2 m of freshwater of density (ρ) = 998 kg/m3
b)
10.1 m of saline water of density (ρ) = 1025 kg/m3
c)
12.5 m of kerosene of density (ρ) = 800 kg/m3
d)
- 6.4 m of carbon tetrachloride of density (ρ) = 1590 kg/m3
 | Mrinalini Sharma answered |
Pressure at sea level = 101.325 kPa
Checking according to given options.
P = hρg
a) ⇒ 10.2 m of fresh water (ρ = 998 kg/m3)
P = 10.2 × 998 × 9.81 = 99861.87 Pa = 99.861 kPa
b) ⇒ 10.1 m of saline water (ρ = 1025 kg/m3)
P = 10.1 × 1025 × 9.81 = 101.558 kPa
c) ⇒ 12.5 m of kerosene of ρ = 800 kg/m3
P = 12.5 × 800 × 9.81 = 98.1 kPa
d) ⇒ 6.4 m of carbon tetrachloride of ρ = 1590 kg/m3
⇒ 6.4 × 1590 × 9.81 = 99.826 kPa
So option b is nearest, so correct
For measuring flow by a Venturimeter, it should be installed in _______.- a)Vertical line
- b)Horizontal line
- c)Inclined line with upward flow
- d)In any direction and in any location
Correct answer is option 'D'. Can you explain this answer?
For measuring flow by a Venturimeter, it should be installed in _______.
a)
Vertical line
b)
Horizontal line
c)
Inclined line with upward flow
d)
In any direction and in any location
 | Gayatri Dasgupta answered |
Venturimeter is a device which measure flow rate of fluid through pipe. It can be used at any position.
When a venture meter is placed in a pipe carrying the fluid whose flow rate is to be measured, a pressure drop occurs between the entrance and throat of the venturimeter. This pressure drop is measured using a differential pressure sensor and when calibrated this pressure drop becomes a measure of flow rate.
The main function of the draft tube in a hydraulic reaction turbine is to- a)Reduce the effective head across the turbine
- b)Increase the discharge and hence the work
- c)Decrease the discharge to prevent flow separation
- d)Increase the effective head across the turbine
Correct answer is option 'D'. Can you explain this answer?
The main function of the draft tube in a hydraulic reaction turbine is to
a)
Reduce the effective head across the turbine
b)
Increase the discharge and hence the work
c)
Decrease the discharge to prevent flow separation
d)
Increase the effective head across the turbine
 | Anshul Sharma answered |
The draft tube is a conduit which connects the runner exit to the tail race where the water is being finally discharged from the turbine. The primary function of the draft tube is to convert kinetic head into pressure head there by increasing effctive head and efficiency.
The mechanical efficiency of an impulse turbine is generally between:- a)73-75
- b)97-99
- c)48-50
- d)88-90
Correct answer is option 'B'. Can you explain this answer?
The mechanical efficiency of an impulse turbine is generally between:
a)
73-75
b)
97-99
c)
48-50
d)
88-90
 | Sarthak Kulkarni answered |
Mechanical efficiency of Impulse turbine is given by:
It generally varies between 97 to 99
Also, volumetric efficiency (ηv) = 97 to 99
Overall efficiency (ηo) = 85 to 90
A hydraulic coupling- a)Connects two shafts rotating at about the same speed.
- b)Connects two shafts running at different speeds.
- c)Is used to augment the torque to the driven shaft.
- d)Is used to connect the centrifugal pump to an electric motor for efficient operation.
Correct answer is option 'B'. Can you explain this answer?
A hydraulic coupling
a)
Connects two shafts rotating at about the same speed.
b)
Connects two shafts running at different speeds.
c)
Is used to augment the torque to the driven shaft.
d)
Is used to connect the centrifugal pump to an electric motor for efficient operation.
 | Sagarika Dey answered |
The fluid or hydraulic coupling is a device used for transmitting power from driving shaft to the driven shaft, running at different speed, with the help of fluid. There is no mechanical connection between the shafts.
The pressure inside a Pelton turbine casing during working________.- a)Increases
- b)Remains constant
- c)Decreases
- d)First decreases and then increases
Correct answer is option 'B'. Can you explain this answer?
The pressure inside a Pelton turbine casing during working________.
a)
Increases
b)
Remains constant
c)
Decreases
d)
First decreases and then increases
| | Sagarika Dey answered |
Pelton wheel is a kind of impulse turbine. As in case of impulse turbine pressure throughout turbine is constant and equal to atmospheric pressure, so only energy available for turbine is kinetic energy of fluid. There is no change in pressure energy as it takes place in reaction turbine.
Calculate the diameter of a pipe of 32000 m long, if it is equivalent to another pipe of 0.2 m diameter and 1000 m long.- a)0.2 m
- b)0.3 m
- c)0.4 m
- d)0.5 m
Correct answer is option 'C'. Can you explain this answer?
Calculate the diameter of a pipe of 32000 m long, if it is equivalent to another pipe of 0.2 m diameter and 1000 m long.
a)
0.2 m
b)
0.3 m
c)
0.4 m
d)
0.5 m
 | Moumita Dasgupta answered |
To find the diameter of a pipe that is equivalent to another pipe in terms of length and diameter, we can use the concept of volume. The volume of a cylinder is given by the formula V = πr^2h, where V is the volume, r is the radius, and h is the height or length of the cylinder.
We are given that the first pipe is 32000 m long and has a diameter of 0.2 m. We need to find the diameter of the second pipe that is equivalent in terms of volume.
Let's first find the radius and height of the first pipe:
Given diameter = 0.2 m
Radius = diameter/2 = 0.2/2 = 0.1 m
Height = 32000 m
Next, let's find the volume of the first pipe:
V1 = π(0.1)^2(32000) = 1005.31 m^3
Now, let's find the radius and height of the second pipe:
Given diameter = ?
Radius = ?
Height = 1000 m
Since the volumes of the two pipes are equal, we can equate the volume of the second pipe to the volume of the first pipe:
V2 = V1
π(r2)^2(1000) = 1005.31
Simplifying the equation, we get:
(r2)^2 = 1005.31/π/1000
(r2)^2 = 0.320
Taking the square root of both sides, we get:
r2 = √0.320
r2 ≈ 0.566 m
Finally, to find the diameter of the second pipe, we multiply the radius by 2:
Diameter = 2(r2) = 2(0.566) ≈ 1.132 m
Therefore, the diameter of the second pipe that is equivalent to the first pipe of 0.2 m diameter and 32000 m long is approximately 1.132 m.
We are given that the first pipe is 32000 m long and has a diameter of 0.2 m. We need to find the diameter of the second pipe that is equivalent in terms of volume.
Let's first find the radius and height of the first pipe:
Given diameter = 0.2 m
Radius = diameter/2 = 0.2/2 = 0.1 m
Height = 32000 m
Next, let's find the volume of the first pipe:
V1 = π(0.1)^2(32000) = 1005.31 m^3
Now, let's find the radius and height of the second pipe:
Given diameter = ?
Radius = ?
Height = 1000 m
Since the volumes of the two pipes are equal, we can equate the volume of the second pipe to the volume of the first pipe:
V2 = V1
π(r2)^2(1000) = 1005.31
Simplifying the equation, we get:
(r2)^2 = 1005.31/π/1000
(r2)^2 = 0.320
Taking the square root of both sides, we get:
r2 = √0.320
r2 ≈ 0.566 m
Finally, to find the diameter of the second pipe, we multiply the radius by 2:
Diameter = 2(r2) = 2(0.566) ≈ 1.132 m
Therefore, the diameter of the second pipe that is equivalent to the first pipe of 0.2 m diameter and 32000 m long is approximately 1.132 m.
The upper surface of a weir over which water flows is known as- a)vein
- b)nappe
- c)sill
- d)weir top
Correct answer is option 'C'. Can you explain this answer?
The upper surface of a weir over which water flows is known as
a)
vein
b)
nappe
c)
sill
d)
weir top
 | Soumya Basak answered |
A weir may be defined as a structure constructed across a river or canal to store water on the upstream side. Water flows over the crest of weir.
The sheet of water flowing through a notch or over a weir is known as nappe or vein. The bottom edge of the notch or the top of a weir over which water flows is known as sill or crest. The height above the bottom of the tank or channel is known as crest height.
Specific speed of a Pelton turbine ranges from- a)12 to 70
- b)80 to 400
- c)300 to 1000
- d)1000 to 1200
Correct answer is option 'A'. Can you explain this answer?
Specific speed of a Pelton turbine ranges from
a)
12 to 70
b)
80 to 400
c)
300 to 1000
d)
1000 to 1200
| | Sagarika Dey answered |
Specific speed: It is defined as the speed of a similar turbine working under a head of 1 m to produce a power output of 1 kW. The specific speed is useful to compare the performance of various type of turbines. The specific speed differs for different type of turbines and is same for the model and actual turbine.
1. The specific speed of Pelton wheel turbine (single jet) is in the range of 10-35
2. The specific speed of Pelton wheel turbine (multiple jets) is in the range of 35-60
3. The specific speed of Francis turbine is in the range of 60-300.
4. The specific speed of Kaplan turbine is greater than 300.
Which of the following pumps is used for pumping viscous fluids?- a)Centrifugal pump
- b)Screw pump
- c)Reciprocating pump
- d)Jet pump
Correct answer is option 'B'. Can you explain this answer?
Which of the following pumps is used for pumping viscous fluids?
a)
Centrifugal pump
b)
Screw pump
c)
Reciprocating pump
d)
Jet pump
| | Sagarika Dey answered |
A screw pump is a type of positive displacement pump that uses two or more screws that intermesh to pressurize fluids and move them in a system. The screws take in fluid then push it out from the other side while increasing its pressure. In offshore and marine installations, a three-spindle screw pump is often used to pump high-pressure viscous fluids.
An object weighs 60 gm in air, 50 gm in water and 40 gm in oil. Then the specific gravity of the oil will be _____.- a)0.25
- b)1
- c)1.5
- d)0.4
Correct answer is option 'D'. Can you explain this answer?
An object weighs 60 gm in air, 50 gm in water and 40 gm in oil. Then the specific gravity of the oil will be _____.
a)
0.25
b)
1
c)
1.5
d)
0.4
 | Neha Choudhury answered |
Given :
Weight of silid in air=60gm
Weight of solid in water=50gm
Weight of solid in oil=40gm
Specific gravity=Relative density of liquid=?
Relative density of liquid
=loss of weight of solid in liquid/loss of weight of solid in water
=(60-40)/50
=20/50
=0.4
∴Specific gravity of oil is 0.4
For starting an axial flow pump, its delivery valve should be _____.- a)Closed
- b)Open
- c)Depends on starting condition and flow desired
- d)Could be either open or closed
Correct answer is option 'B'. Can you explain this answer?
For starting an axial flow pump, its delivery valve should be _____.
a)
Closed
b)
Open
c)
Depends on starting condition and flow desired
d)
Could be either open or closed
| | Anshul Sharma answered |
Axial flow pumps have poor suction capability, so require more starting power. They are started against an open valve to minimize the starting power required.
By which one of the following, a small quantity of water may be lifted to a great height- a)Hydraulic ram
- b)Hydraulic crane
- c)Hydraulic lift
- d)Hydraulic coupling
Correct answer is option 'A'. Can you explain this answer?
By which one of the following, a small quantity of water may be lifted to a great height
a)
Hydraulic ram
b)
Hydraulic crane
c)
Hydraulic lift
d)
Hydraulic coupling
| | Raghav Saini answered |
Hydraulic ram is used to lift small quantity of water to greater height from large quantities of water available at smaller heights.
Which one of the following statement is CORRECT about the centre of buoyancy?- a)It is the point where buoyant force act.
- b)It coincides with the centroid of volume of water displaced
- c)It is the point where buoyant force act and It coincides with the centroid of volume of water displaced
- d)It acts outside the body.
Correct answer is option 'C'. Can you explain this answer?
Which one of the following statement is CORRECT about the centre of buoyancy?
a)
It is the point where buoyant force act.
b)
It coincides with the centroid of volume of water displaced
c)
It is the point where buoyant force act and It coincides with the centroid of volume of water displaced
d)
It acts outside the body.
 | Anshu Patel answered |
Objects in a fluid experience an upward force. Whenever an object is immersed in a fluid, either liquid or gas, it experiences a buoyant force. A buoyant force is a force which pushes upward on an object and is caused by displaced fluid.
The centre of buoyancy is the point where the resultant Buoyant force acts, It is the point of the C.G of the displaced fluid.
A single-stage impulse turbine with a diameter of 120 cm runs at 3000 rpm. If the blade speed ratio is 0.42, then, the inlet velocity of steam will be- a)79 m/s
- b)188 m/s
- c)450 m/s
- d)900 m/s
Correct answer is option 'C'. Can you explain this answer?
A single-stage impulse turbine with a diameter of 120 cm runs at 3000 rpm. If the blade speed ratio is 0.42, then, the inlet velocity of steam will be
a)
79 m/s
b)
188 m/s
c)
450 m/s
d)
900 m/s
 | Sahana Choudhary answered |
Given data:
Diameter of the turbine (D) = 120 cm
Blade speed ratio (λ) = 0.42
Rotational speed (N) = 3000 rpm
Formula used:
Blade speed ratio (λ) = u / V1
where u = blade speed and V1 = inlet velocity of steam
Calculation:
1. First, let's calculate the blade speed (u) using the formula:
u = λ * V1
= 0.42 * V1
2. Next, let's calculate the blade speed in m/s by converting the rotational speed from rpm to m/s:
u (m/s) = (π * D * N) / 60
= (π * 1.2 * 3000) / 60
= 188.5 m/s (approx.)
3. Now, equating the two expressions for blade speed (u), we have:
0.42 * V1 = 188.5
V1 = 188.5 / 0.42
V1 = 448.81 m/s (approx.)
Therefore, the inlet velocity of steam is approximately 448.81 m/s.
Conclusion:
The correct answer is option (c) 450 m/s.
Diameter of the turbine (D) = 120 cm
Blade speed ratio (λ) = 0.42
Rotational speed (N) = 3000 rpm
Formula used:
Blade speed ratio (λ) = u / V1
where u = blade speed and V1 = inlet velocity of steam
Calculation:
1. First, let's calculate the blade speed (u) using the formula:
u = λ * V1
= 0.42 * V1
2. Next, let's calculate the blade speed in m/s by converting the rotational speed from rpm to m/s:
u (m/s) = (π * D * N) / 60
= (π * 1.2 * 3000) / 60
= 188.5 m/s (approx.)
3. Now, equating the two expressions for blade speed (u), we have:
0.42 * V1 = 188.5
V1 = 188.5 / 0.42
V1 = 448.81 m/s (approx.)
Therefore, the inlet velocity of steam is approximately 448.81 m/s.
Conclusion:
The correct answer is option (c) 450 m/s.
If the discharge of a centrifugal pump is throttled then its suction lift- a)Decreases
- b)First increases and then decreases
- c)Remains unchanged
- d)Increases
Correct answer is option 'D'. Can you explain this answer?
If the discharge of a centrifugal pump is throttled then its suction lift
a)
Decreases
b)
First increases and then decreases
c)
Remains unchanged
d)
Increases
 | Anushka Bose answered |
When the discharge of a centrifugal pump is throttled, the suction lift of the pump increases. This is because throttling the discharge of the pump restricts the flow of fluid from the pump, which in turn creates a higher pressure differential across the pump.
Explanation:
- Throttling the discharge of a centrifugal pump means reducing the flow rate of fluid being discharged from the pump. This can be done by partially closing a valve on the discharge line.
- When the discharge is throttled, the flow rate of fluid leaving the pump decreases. However, the impeller of the pump continues to rotate at the same speed, causing the impeller to generate a higher pressure head.
- The increased pressure head at the discharge of the pump creates a higher pressure differential between the suction and discharge sides of the pump.
- According to Bernoulli's principle, the pressure differential between the suction and discharge sides of the pump affects the suction lift. A higher pressure differential corresponds to a higher suction lift.
- Therefore, when the discharge of a centrifugal pump is throttled, the suction lift of the pump increases.
- It is important to note that while the suction lift increases, the actual suction pressure at the pump inlet may decrease due to the higher pressure differential. This means that the pump may experience a reduction in performance, as it is operating at a lower suction pressure.
In summary, when the discharge of a centrifugal pump is throttled, the suction lift of the pump increases due to the higher pressure differential across the pump. This can result in a decrease in pump performance, as the pump is operating at a lower suction pressure.
Explanation:
- Throttling the discharge of a centrifugal pump means reducing the flow rate of fluid being discharged from the pump. This can be done by partially closing a valve on the discharge line.
- When the discharge is throttled, the flow rate of fluid leaving the pump decreases. However, the impeller of the pump continues to rotate at the same speed, causing the impeller to generate a higher pressure head.
- The increased pressure head at the discharge of the pump creates a higher pressure differential between the suction and discharge sides of the pump.
- According to Bernoulli's principle, the pressure differential between the suction and discharge sides of the pump affects the suction lift. A higher pressure differential corresponds to a higher suction lift.
- Therefore, when the discharge of a centrifugal pump is throttled, the suction lift of the pump increases.
- It is important to note that while the suction lift increases, the actual suction pressure at the pump inlet may decrease due to the higher pressure differential. This means that the pump may experience a reduction in performance, as it is operating at a lower suction pressure.
In summary, when the discharge of a centrifugal pump is throttled, the suction lift of the pump increases due to the higher pressure differential across the pump. This can result in a decrease in pump performance, as the pump is operating at a lower suction pressure.
An impulse hydraulic turbine:- a)Always operates while submerged completely in water
- b)Makes use of a draft tube
- c)Converts pressure head into velocity head throughout the vane
- d)Operates by initial complete conversion of potential energy to kinetic energy
Correct answer is option 'D'. Can you explain this answer?
An impulse hydraulic turbine:
a)
Always operates while submerged completely in water
b)
Makes use of a draft tube
c)
Converts pressure head into velocity head throughout the vane
d)
Operates by initial complete conversion of potential energy to kinetic energy
| | Sagarika Dey answered |
Impulse turbine: At the inlet of the turbine, the energy available is only kinetic energy
Example: Pelton Turbine
Reaction Turbine: At the inlet of the turbine, the water possesses kinetic energy as well as pressure energy
Example: Francis Turbine, Kaplan Turbine
The shear stress-strain graph for a Newtonian fluid is a- a)Straight line
- b)Parabolic Curve
- c)Hyperbolic Curve
- d)Elliptical
Correct answer is option 'A'. Can you explain this answer?
The shear stress-strain graph for a Newtonian fluid is a
a)
Straight line
b)
Parabolic Curve
c)
Hyperbolic Curve
d)
Elliptical
| | Ameya Kaur answered |
Newtonian fluids defined as fluids for which the shear stress is linearly proportional to the shear strain rate. Newtonian fluids are analogous to elastic solids (Hooke’s law: stress proportional to strain). Any common fluids, such as air and other gases, water, kerosene, gasoline, and other oil-based liquids, are Newtonian fluids.
Fluids for which the shear stress is not linearly related to the shear strain rate are called non- Newtonian fluids. examples include slurries and colloidal suspensions, polymer solutions, blood, paste, and cake batter.
Two Pelton wheels A and B are having same specific speed and are working under the same head. Wheel A provides 900 kW at 800 RPM. If wheel B produces 100 kW, then its RPM will be- a)4000
- b)7200
- c)2400
- d)1250
Correct answer is option 'C'. Can you explain this answer?
Two Pelton wheels A and B are having same specific speed and are working under the same head. Wheel A provides 900 kW at 800 RPM. If wheel B produces 100 kW, then its RPM will be
a)
4000
b)
7200
c)
2400
d)
1250
| | Sagarika Dey answered |
For same specific speed and working under the same head i.e. NS1=NS2&H1=H2
N2 = 2400 RPM
Which of the following pump is successfully used for lifting water to the turbine?- a)Air lift pump
- b)Centrifugal pump
- c)Reciprocating pump
- d)Jet pump
Correct answer is option 'D'. Can you explain this answer?
Which of the following pump is successfully used for lifting water to the turbine?
a)
Air lift pump
b)
Centrifugal pump
c)
Reciprocating pump
d)
Jet pump
| | Sagarika Dey answered |
For lifting water to the turbine, A pump similar to a turbine pipe is used but it works by redirecting water back down to the intake to help lift the water.
While, centrifugal pumps are used to transport fluids by the conversion of rotational kinetic Energy to the hydrodynamic energy of the fluid flow. Reciprocating pumps are not used in turbine function.
Centrifugal pump is based on the principle of_______- a)Turbulent force
- b)Centrifugal force
- c)Vortex force
- d)Centripetal force
Correct answer is option 'B'. Can you explain this answer?
Centrifugal pump is based on the principle of_______
a)
Turbulent force
b)
Centrifugal force
c)
Vortex force
d)
Centripetal force
| | Raghav Saini answered |
Centrifugal Pump is a hydraulic machine which converts mechanical energy into hydraulic energy (pressure energy) by the action of centrifugal force acting on the fluid.
Rotation of a centrifugal pump impeller causes the liquid it contains to move outwards from the centre to beyond the circumference of the impeller. The revolving liquid is impelled around the periphery of the impeller by centrifugal effect. Displaced liquid in moving from the casing to the delivery pipe, causes flow in the discharge side of the system.
In which type of the following flow, loses are more?- a)Critical flow
- b)Laminar flow
- c)Transitional flow
- d)Turbulent flow
Correct answer is option 'D'. Can you explain this answer?
In which type of the following flow, loses are more?
a)
Critical flow
b)
Laminar flow
c)
Transitional flow
d)
Turbulent flow
| | Nitya Nambiar answered |
Losses are governed by hf
For laminar flow, hf α f2
Where f1 = friction factor
Put Re = 2000
Forturbulentflow, 
Even for Re = 2000
f2 = 0.039
f2 > f1
So, losses are more in turbulent flow.
Where is the regulating valve provided in a centrifugal pump- a)Casing
- b)Delivery pipe
- c)Suction pipe
- d)Impeller
Correct answer is option 'B'. Can you explain this answer?
Where is the regulating valve provided in a centrifugal pump
a)
Casing
b)
Delivery pipe
c)
Suction pipe
d)
Impeller
| | Anuj Chauhan answered |
The regulating valve is provided on the delivery pipe. It regulates the flow of liquid after its exit from the pump. It is usually a sluice type of valve.
A mono pump is also knows as;- a)Piston
- b)A group of vacuum
- c)Centrifugal
- d)Positive acting rotary
Correct answer is option 'D'. Can you explain this answer?
A mono pump is also knows as;
a)
Piston
b)
A group of vacuum
c)
Centrifugal
d)
Positive acting rotary
| | Sagarika Dey answered |
Another form of positive acting rotary pump is the single - screw extruder pump typified by the Mono pump. It has a specially shaped metal helical rotor revolves eccentrically within a resilient rubber or plastic double helix, thus creating a continuous forming cavity which processes towards the discharge of the pump. This type of pump is suitable for pumping slurries and pastes, weather Newtonian or Non - Newtonian in character.
Double hemispherical buckets are used in- a)Kaplan Turbine
- b)Francis turbine
- c)Propeller turbine
- d)Pelton wheel turbine
Correct answer is option 'D'. Can you explain this answer?
Double hemispherical buckets are used in
a)
Kaplan Turbine
b)
Francis turbine
c)
Propeller turbine
d)
Pelton wheel turbine
| | Anuj Chauhan answered |
The Pelton wheel or Pelton turbine is a tangential flow impulse turbine. The water strikes the bucket along the tangent of the runner. The shape of the buckets is of double hemispherical cup or bowl. Each bucket is divided into two symmetrical parts by a dividing wall known as splitter. The jet of water strikes on the splitter. The splitter divides the jet into two equal parts and the jet comes out at the outer edge of the bucket. The buckets are shaped in such a way that the jets gets deflected through 160 ° or 170 °.
Cavitation is caused by- a)high velocity
- b)low pressure
- c)high pressure
- d)high temperature
Correct answer is option 'B'. Can you explain this answer?
Cavitation is caused by
a)
high velocity
b)
low pressure
c)
high pressure
d)
high temperature
| | Raghav Saini answered |
Cavitation is the formation of gas bubbles of a flowing liquid in a region where the pressure of liquid falls below its vapour pressure i.e. low pressure.
If α is the blade angle at the outlet, then the maximum hydraulic efficiency of an ideal impulse turbine is- a)
- b)
- c)
- d)
Correct answer is option 'A'. Can you explain this answer?
If α is the blade angle at the outlet, then the maximum hydraulic efficiency of an ideal impulse turbine is
a)
b)
c)
d)
| | Anuj Chauhan answered |
Hydraulic efficiency of Pelton wheel= 
Here, k = friction factor
u = blade speed/bucket sp eed
v = jet speed
α = blade angle
For maximum efficiency the bucket speed should be halt of jet speed i.e. 
Thus, respective maximum efficiency is 
And, if bucket is frictionless, k = 1
The fluid forces considered in the Navier-Strokes equation are ______.- a)Gravity, pressure and viscous
- b)Gravity, pressure and turbulent
- c)Pressure, viscous and turbulent
- d)Gravity, viscous and turbulent
Correct answer is option 'A'. Can you explain this answer?
The fluid forces considered in the Navier-Strokes equation are ______.
a)
Gravity, pressure and viscous
b)
Gravity, pressure and turbulent
c)
Pressure, viscous and turbulent
d)
Gravity, viscous and turbulent
| | Swara Gupta answered |
Navier-Strokes equation describe the motion of viscous fluid substances. These balance equations arise from applying Newton's second law to fluid motion, together with the assumption that the stress in the fluid is the sum of a diffusing viscous term (proportional to the gradient of velocity) and a pressure term-hence describing viscous flow.
Which of the following conditions will be satisfied by steady irrotational flow?
- a)1 and 2
- b)2 and 3
- c)1 and 3
- d)1,2 and 3
Correct answer is option 'B'. Can you explain this answer?
Which of the following conditions will be satisfied by steady irrotational flow?
a)
1 and 2
b)
2 and 3
c)
1 and 3
d)
1,2 and 3
| | Rashi Shah answered |
For steady, irrotational flow following two condition must be fulfilled:
i) flow possibility
ii) ωz = 0
Which of the following has got the highest of specific speed?- a)Francis
- b)Kaplan
- c)Pelton wheel with three jet
- d)Pelton wheel with single jet
Correct answer is option 'B'. Can you explain this answer?
Which of the following has got the highest of specific speed?
a)
Francis
b)
Kaplan
c)
Pelton wheel with three jet
d)
Pelton wheel with single jet
| | Sagarika Dey answered |
Specific speed: It is defined as the speed of a similar turbine working under a head of 1 m to produce a power output of 1 kW. The specific speed is useful to compare the performance of the various type of turbines. The specific speed differs for the different type of turbines and is the same for the model and actual turbine.
Following are the range of specific speed of different turbines
- The specific speed of Pelton wheel turbine (single jet) is in the range of 10-35
- The specific speed of Pelton wheel turbine (multiple jets) is in the range of 35-60
- The specific speed of Francis turbine is in the range of 60-300.
- The specific speed of Kaplan/propeller turbine is greater than 300.
So the Kaplan turbine has the highest specific speed.
Which one of the following equations represents the continuity equation for steady compressible fluid flow?- a)
- b)
- c)
- d)
Correct answer is option 'D'. Can you explain this answer?
Which one of the following equations represents the continuity equation for steady compressible fluid flow?
a)
b)
c)
d)
| | Samarth Ghoshal answered |
for steady flow
Continuity equation for steady compressible flow is
For very high discharge at low pressure such as for flood control and irrigation applications, which of the following types of pump is preferred?- a)Centrifugal
- b)Axial Flow
- c)Reciprocating
- d)Mixed Flow
Correct answer is option 'B'. Can you explain this answer?
For very high discharge at low pressure such as for flood control and irrigation applications, which of the following types of pump is preferred?
a)
Centrifugal
b)
Axial Flow
c)
Reciprocating
d)
Mixed Flow
 | Mahi Kaur answered |
The main advantage of an Axial flow pump is that it has a relatively high discharge (flow rate) at a relative low head.
For example, it can pump up to 3 times more water and other fluids at lifts of less than 4 meters as compared to the more common radial - flow or centrifugal pump. They are used by smaller farmers for crop irrigation, drainage and fisheries.
An oil of kinematic viscosity of 0.5 stokes flow through a pipe of 20 cm diameter. What is the velocity if the flow is critical?- a)0.5 m/s
- b)0.9 m/s
- c)1.5 m/s
- d)2 m/s
Correct answer is option 'A'. Can you explain this answer?
An oil of kinematic viscosity of 0.5 stokes flow through a pipe of 20 cm diameter. What is the velocity if the flow is critical?
a)
0.5 m/s
b)
0.9 m/s
c)
1.5 m/s
d)
2 m/s
| | Anjali Sengupta answered |
ν = 0.5 × 10-4 m2/s
D = 20 cm
For critical, Re = 2000
While representing the energy equation, the difference between the total head line and Hydaullic gradient line is:- a)Velocity head
- b)Piezometric head
- c)Elevation
- d)Pressure head
Correct answer is option 'A'. Can you explain this answer?
While representing the energy equation, the difference between the total head line and Hydaullic gradient line is:
a)
Velocity head
b)
Piezometric head
c)
Elevation
d)
Pressure head
| | Janhavi Choudhary answered |
The difference between the total head line and Hydraullic gradient line is always constant for particular pipe flow and it is equal to the velocity head.
In centrifugal pumps, maximum efficiency is obtained when the blades are- a)Straight
- b)Bent forward
- c)Bent backward
- d)Radial
Correct answer is option 'C'. Can you explain this answer?
In centrifugal pumps, maximum efficiency is obtained when the blades are
a)
Straight
b)
Bent forward
c)
Bent backward
d)
Radial
| | Anuj Chauhan answered |
In centrifugal pump backward curve vanes are preferred.
Equation of continuity results from the principal of conservation of _____. - a)Energy
- b)Flow
- c)Mass
- d)Momentum
Correct answer is option 'C'. Can you explain this answer?
Equation of continuity results from the principal of conservation of _____.
a)
Energy
b)
Flow
c)
Mass
d)
Momentum
| | Shraddha Datta answered |
The law of conservation of mass states that mass can neither be created nor be destroyed.
Rate at which mass enters the region = Rate at which mass leaves the region + Rate of accumulation of mass in the region
The above statement can be expressed analytically in terms of velocity and density field of a flow and the resulting expression is known as the equation of continuity or the continuity equation.
\(\begin{array}{l} \frac{{\partial \rho }}{{\partial t}} + \frac{\partial }{{\partial x}}\left( {\rho u} \right) + \frac{\partial }{{\partial y}}\left( {\rho v} \right) + \frac{\partial }{{\partial z}}\left( {\rho w} \right) = 0\\ \frac{{\partial \rho }}{{\partial t}} + .\left( {{\rm{\rho \vec V}}} \right) = 0 \end{array}\)
Property of a fluid by which molecules of different kinds of fluids are attracted to each other is called _____.- a)Adhesion
- b)Cohesion
- c)Viscosity
- d)Compressibility
Correct answer is option 'A'. Can you explain this answer?
Property of a fluid by which molecules of different kinds of fluids are attracted to each other is called _____.
a)
Adhesion
b)
Cohesion
c)
Viscosity
d)
Compressibility
| | Divyansh Goyal answered |
- Adhesion is the mutual attraction between unlike molecules that causes them to cling to one another
- Capillary action and meniscus (the curved surface which is formed by any liquid in a cylinder) are the effects of adhesion
- Cohesion is the mutual attraction between like molecules that causes them to stick together.
- Surface tension, Capillary action, and meniscus are the effects of cohesion.
An increase in pressure of a liquid from 7.5 MPa to 15 MPa results into 0.2 percent decrease in its volume. The coefficient of compressibility of the liquid in m2/N is- a)0.267 × 10-9
- b)2.67 × 10-9
- c)1 × 10-9
- d)None of the above
Correct answer is option 'A'. Can you explain this answer?
An increase in pressure of a liquid from 7.5 MPa to 15 MPa results into 0.2 percent decrease in its volume. The coefficient of compressibility of the liquid in m2/N is
a)
0.267 × 10-9
b)
2.67 × 10-9
c)
1 × 10-9
d)
None of the above
| | Yash Das answered |
dV = 0.2%
Compressibility (β) = 
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