Fluid Mechanics And Machinery Set 7

Mechanical Engineering

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This set of Fluid Mechanics and Machinery Multiple Choice Questions & Answers (MCQs) focuses on Fluid Mechanics And Machinery Set 7

Q1 | In the figure shown below, which of the following type of runners has the blade curvature as shown in the above figure (The arrow denotes direction of blade motion)?
  • information insufficient to determine
  • slow runner
  • medium runner
  • fast runner
Answer: slow runner
Explaination:
fast runners have forward curved blades, where slow runners have backward curved blades. the blades shown in the figure are backward curved blades of a runner, which are used for slow runners.
Q2 | category of 
  • energy absorbing machines
  • energy generating machines
  • power absorbing machines
  • energy transfer machines
Answer: energy transfer machines
Explaination:
hydraulic coupling is a device used for transmitting rotation between shafts by means of acceleration and deceleration of hydraulic fluid.
Q3 | The electric power which is obtained from hydraulic energy 
  • thermal power
  • mechanical power
  • solar power
  • hydroelectric power
Answer: hydroelectric power
Explaination:
hydroelectric power is generated by using hydraulic machines. potential energy of water is converted to mechanical energy which is connected to dynamo to generate electrical energy.
Q4 | generating power 
  • thermal power
  • nuclear power
  • hydroelectric power
  • electric power
Answer: hydroelectric power
Explaination:
hydraulic energy is renewable source of energy in which potential energy of water is converted to mechanical energy which is connected to dynamo to generate electrical energy.
Q5 | Pen stocks are made up of 
  • steel
  • cast iron
  • mild steel
  • wrought iron
Answer: steel
Explaination:
penstocks are channels which transport water from reservoir to turbines which are usually made up of cast iron or concrete.
Q6 | turbines, if vanes are fixed to hub of turbine
  • propeller turbine
  • francis turbine
  • kaplan turbine
  • pelton turbine
Answer: propeller turbine
Explaination:
axial flow turbine is a turbine in which water flows axially outwards, if vanes are fixed to hub of turbine it is known as propeller turbine but if vanes are free to move it is known as kaplan turbine.
Q7 | Francis and Kaplan turbines are known as
  • impulse turbine
  • reaction turbine
  • axial flow turbine
  • mixed flow turbine
Answer: reaction turbine
Explaination:
francis and kaplan are reaction
Q8 | The important type of axial flow reaction turbines are  
  • propeller and pelton turbines
  • kaplan and francis turbines
  • propeller and francis turbines
  • propeller and kaplan turbines
Answer: propeller and kaplan turbines
Explaination:
axial flow turbine is a turbine in which water flows axially outwards and turbines fall into this category are propeller and kaplan turbines.
Q9 | Specific speed of reaction turbine is between?
  • 5 and 50
  • 10 and 100
  • 100 and 150
  • 150 and 300
Answer: 10 and 100
Explaination:
specific turbines of reaction turbines such as francis and kaplan lie under the range 10-100.
Q10 | Impulse turbine is generally fitted at
  • at the level of tail race
  • above the tail race
  • below the tail race
  • about 2.5mts above tail race to avoid cavitations.
Answer: above the tail race
Explaination:
impulse turbine is fitted above
Q11 | Draft tube is also called 
  • straight divergent tube
  • simple elbow tube
  • thermal tube
  • elbow tube with varying cross section
Answer: straight divergent tube
Explaination:
draft tube is one of the most commonly used in the kaplan turbine. it works as an outlet at the kaplan turbine.
Q12 | A draft tube helps in converting kinetic energy into 
  • electrical work
  • mechanical work
  • chemical work
  • thermal work
Answer: mechanical work
Explaination:
turbine extracts energy and converts it into useful work. turbine is a vortex related device. it means turbulence. steam turbine converts energy into mechanical work by extracting thermal energy from pressurized steam.
Q13 | Most common application of the draft tube is  
  • rotor
  • motor
  • pump
  • filter
Answer: pump
Explaination:
most common application of the draft tube is different types of pumps. it plays an important role in the putlet of the pump and the turbine.
Q14 | Draft tube consists of conical diffuser with angles of 
  • 10 deg
  • 20 deg
  • 30 deg
  • 40 deg
Answer: 10 deg
Explaination:
draft tube consists of conical diffuser with angles of 10 degrees with respect to its position, draft tubes are situated in the outlet of the turbine.
Q15 | What is the purpose of a Draft tube?
  • to prevent flow separation
  • to avoid pressure drag
  • to prevent rejection of heat
  • to increase efficiency
Answer: to prevent flow separation
Explaination:
draft tube in a turbine and pumps helps to prevent flow separation in order to increase the turbine efficiency and increase its performance.
Q16 | What is the maximum value of efficiency in a draft tube?
  • 100
  • 50
  • 90
  • 40
Answer: 90
Explaination:
the maximum value of efficiency in a draft tube is 90 percent. it cannot exceed more than 90 percent because of the heat losses due to flow of fluid.
Q17 | Turbine that consists of draft tubes is called as 
  • impulse turbine
  • curtis turbine
  • rateau turbine
  • reaction turbine
Answer: reaction turbine
Explaination:
a turbine that consists of draft tubes is called as a reaction turbine. reaction turbines make maximum use of the draft tubes for improving its performance characteristics.
Q18 | Which of the following is a 50 percent reaction turbine?
  • parsons turbine
  • curtis turbine
  • rateau turbine
  • pelton wheel
Answer: parsons turbine
Explaination:
a turbine that consists of moving nozzles which are alternating with the fixed nozzles is called as a reaction turbine.
Q19 | The simple elbow draft tube helps to cut down the cost of excavation.
  • true
  • false
Answer: true
Explaination:
the simple elbow draft tube helps to cut down the cost of excavation. the simple elbow draft tube is placed close to the
Q20 | The exit diameter for a simple elbow draft tube should be 
  • large
  • small
  • very small
  • same
Answer: large
Explaination:
the exit diameter for a simple elbow draft tube should be large as possible. it helps to cut down the cutdown the cost and recover the kinetic energy at the outlet of runner. the simple elbow draft tube is placed close to the tail race.
Q21 | Properties that do not affect a draft tube is
  • pressure
  • temperature
  • pressure velocity
  • velocity
Answer: temperature
Explaination:
temperature does not affect the performance of the draft tube. with increase and decrease of temperature of fluid in a draft tube, the draft tube remains the same.
Q22 | The other name for elbow with varying cross section tube is called 
  • pressure tube
  • bent draft tube
  • velocity tube
  • sink tube
Answer: bent draft tube
Explaination:
the other name for elbow with varying cross section tube is called bent draft tube. it is so called because only the bent part is of varying cross section. thus, the answer is bent draft tube.
Q23 | type draft tube?
  • 10
  • 30
  • 60
  • 90
Answer: 60
Explaination:
the efficiency of the simple elbow type draft tube is 60 percent. the exit diameter for a simple elbow draft tube should be large as possible. it helps to cut down the cutdown the cost and recover the kinetic energy at the outlet of runner. the simple elbow draft tube is placed close to the tail race.
Q24 | The horizontal portion of the draft tube is usually bent to prevent entry of air from the exit end.
  • true
  • false
Answer: true
Explaination:
the horizontal portion of the draft tube is usually bent to prevent entry of air from the exit end. this might lead to a mixing up of gases. in order to avoid this, it is important to avoid air entry from exit.
Q25 | In nozzle governing, the flow rate of steam is regulated by  
  • nozzles
  • pumping
  • drafting
  • intercooling
Answer: nozzles
Explaination:
the process of controlling the flow rate of a substance is called as
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