Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan (A) With greater number of blades (B) Of increased diameter (C) Both (A) & (B) (D) Neither (A) nor (B)

Noise produced by cooling fans (employed in air cooled heat
exchangers or cooling tower) is mainly caused due to the turbulence created
by blade passage through air. It can be reduced by use of a slower fan
(A) With greater number of blades
(B) Of increased diameter
(C) Both (A) & (B)
(D) Neither (A) nor (B)
by

1 Answer

Answer :

(C) Both (A) & (B)
by

Related questions

In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the (A) Range is 15°F (B) Approach is 10°F (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the (A) Range is 15°F (B) Approach is 10°F (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the (A) Range is 15°F (B) Approach is 10°F (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the (A) Range is 15°F (B) Approach is 10°F (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

How is air produced in mechanical cooling tower 1 air fan 2 propeller fans 3 air blowers 4 propeller blowers

Description : How is air produced in mechanical cooling tower 1 air fan 2 propeller fans 3 air blowers 4 propeller blowers

Last Answer : 2 propeller fans

Heat load in a cooling tower (A) Means the amount of heat thrown away (KCal/hr.) by the cooling tower (B) Is equal to the number of kg, of water circulated times the cooling range (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Heat load in a cooling tower (A) Means the amount of heat thrown away (KCal/hr.) by the cooling tower (B) Is equal to the number of kg, of water circulated times the cooling range (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Use of natural draft cooling tower is practised, when the air has low (A) Humidity (B) Temperature (C) Both 'a' & 'b' (D) Neither 'a' nor 'b'

Description : Use of natural draft cooling tower is practised, when the air has low (A) Humidity (B) Temperature (C) Both 'a' & 'b' (D) Neither 'a' nor 'b'

Last Answer : (C) Both 'a' & 'b

Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation (B) Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in formation & collapse of vapor cavities (C) Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines resulting in audible noise(D) Large scale cavitation cannot damage pipeline, restrict fluid flow anddamage steam turbine blades

Description : Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation ... (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades

Last Answer : (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades

Pick out the wrong statement pertaining to the cooling towers. (A) In case of induced draft cooling tower, the fan is placed at the top of the tower (B) Effectiveness of forced draft cooling tower is reduced by the recirculation of the humid and hot discharged air (C) A natural draft cooling tower is recommended to be used, when the air humidity is low and air temperature is also low (D) Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

Description : Pick out the wrong statement pertaining to the cooling towers. (A) In case of induced draft cooling tower, the fan is placed at the top of the tower (B) Effectiveness of ... Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

Last Answer : (D) Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

Cooling tower is a ______device a) Heat absorption b) heat rejection c) Both a and b c) neither a nor b

Description : Cooling tower is a ______device a) Heat absorption b) heat rejection c) Both a and b c) neither a nor b

Last Answer : heat rejection

Aerodynamic noise resulting from turbulent gas flow is the most prevalent source of valve noise in fluid flow control. It is caused due to (A) Reynold stresses (B) Shear forces (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Aerodynamic noise resulting from turbulent gas flow is the most prevalent source of valve noise in fluid flow control. It is caused due to (A) Reynold stresses (B) Shear forces (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

In a gas-liquid shell and tube heat exchanger, the(A) Presence of a non-condensable gas decreases the condensing film co￾efficient (B) Gases under high pressure are routed through the tube side, because high pressure gases are corrosive in nature (C) Gases to be heated/cooled is normally routed through the shell side, because the corrosion caused by the cooling water or steam condensate remain localised to the tubes (D) All 'a', 'b' & 'c'

Description : In a gas-liquid shell and tube heat exchanger, the (A) Presence of a non-condensable gas decreases the condensing film co￾efficient (B) Gases under high pressure are routed through the tube side, because high pressure ... water or steam condensate remain localised to the tubes (D) All 'a', 'b' & 'c'

Last Answer : (D) All 'a', 'b' & 'c'

How is air produced in mechanical draught cooling tower? a) Air Tuyeres b) Propeller fans c) Air blowers d) Louvre

Description : How is air produced in mechanical draught cooling tower? a) Air Tuyeres b) Propeller fans c) Air blowers d) Louvre

Last Answer : Propeller fans

How is air produced in mechanical draught cooling tower? A] Air Tuyeres. B] Propeller fans C] Air blowers. D] Louvre

Description : How is air produced in mechanical draught cooling tower? A] Air Tuyeres. B] Propeller fans C] Air blowers. D] Louvre

Last Answer : B] Propeller fans

Pick out the wrong statement (A) A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity (B) When water is cooled from 80 to 70°C by exposure to the air with a wet bulb temperature of 60°C, then both the approach & the range would be 10°C (C) For unsaturated air-water vapor mixture at atmospheric conditions, the wet bulb temperature & adiabatic cooling lines are the same (D) Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure

Description : Pick out the wrong statement (A) A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity (B) When water is cooled from 80 to 70°C by exposure ... & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure

Last Answer : (D) Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure

In a furnace employing forced draught as compared to induced draught, (A) Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced (B) The fan operates hot and hence blades are liable to corrosion and erosion (C) Positive pressure exists in the furnace (D) None of these

Description : In a furnace employing forced draught as compared to induced draught, (A) Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced (B) The fan operates hot and hence blades are liable to corrosion and erosion (C) Positive pressure exists in the furnace (D) None of these

Last Answer : (C) Positive pressure exists in the furnace

The term "cooling range" in a cooling tower refers to the difference in the temperature of (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air(B) Hot water entering the tower and the wet bulb temperature of thesurrounding air(C) Hot water entering the tower and the cooled water leaving the tower(D) None of these

Description : The term "cooling range" in a cooling tower refers to the difference in the temperature of (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air (B) Hot water entering the ... air (C) Hot water entering the tower and the cooled water leaving the tower (D) None of these

Last Answer : (C) Hot water entering the tower and the cooled water leaving the tower

The term "approach" in a cooling tower refers to the difference in the temperature of the (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air (B) Hot water entering the tower and the wet bulb temperature of the surrounding air (C) Hot water entering and the cooled water leaving the cooling tower (D) None of these

Description : The term "approach" in a cooling tower refers to the difference in the temperature of the (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air (B ... (C) Hot water entering and the cooled water leaving the cooling tower (D) None of these

Last Answer : (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air

The temperature of water cooled in cooling tower is always __________ temperature of entering air. (A) More than the wet bulb (B) Less than the wet bulb (C) Equal to the wet bulb (D) Equal to the dry bulb

Description : The temperature of water cooled in cooling tower is always __________ temperature of entering air. (A) More than the wet bulb (B) Less than the wet bulb (C) Equal to the wet bulb (D) Equal to the dry bulb

Last Answer : (A) More than the wet bulb

The minimum temperature to which the water can be cooled in a cooling tower is the __________ temperature of air. (A) Ambient (B) Dry bulb (C) Dew point (D) Wet bulb

Description : The minimum temperature to which the water can be cooled in a cooling tower is the __________ temperature of air. (A) Ambient (B) Dry bulb (C) Dew point (D) Wet bulb

Last Answer : C) Dew point

Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the __________ temperature of air. (A) Wet bulb (B) Dry bulb (C) Saturation (D) Dew point

Description : Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the __________ temperature of air. (A) Wet bulb (B) Dry bulb (C) Saturation (D) Dew point

Last Answer : Option A

Double pipe heat exchangers are preferably useful, when (A) High viscosity liquid is to be cooled (B) Requirement of heat transfer area is low (C) Overall heat transfer co-efficient is very high (D) A corrosive liquid is to be heated

Description : Double pipe heat exchangers are preferably useful, when (A) High viscosity liquid is to be cooled (B) Requirement of heat transfer area is low (C) Overall heat transfer co-efficient is very high (D) A corrosive liquid is to be heated

Last Answer : (B) Requirement of heat transfer area is low

High noise levels produced during operation of fans and compressors can be reduced by using (A) Mufflers (silencers) (B) Acoustic absorbent (C) Lagging of noisy duct (D) None of these

Description : High noise levels produced during operation of fans and compressors can be reduced by using (A) Mufflers (silencers) (B) Acoustic absorbent (C) Lagging of noisy duct (D) None of these

Last Answer : (A) Mufflers (silencers)

Which statement best describes the operating principle of a constant-speed propeller? a. As throttle setting is changed by the pilot, the prop governor causes pitch angle of the propeller blades to remain unchanged b. The propeller control regulates the engine RPM and in turn the propeller RPM c. A high blade angle, or increased pitch, reduces the propeller drag and allows more engine power for take-offs d. As the propeller control setting is changed by the pilot, the RPM of the engines remains constant as the pitch angle of the propeller changes

Description : Which statement best describes the operating principle of a constant-speed propeller? a. As throttle setting is changed by the pilot, the prop governor causes pitch angle of the propeller blades to ... the pilot, the RPM of the engines remains constant as the pitch angle of the propeller changes

Last Answer : b. The propeller control regulates the engine RPM and in turn the propeller RPM

The following types of blades are used with the rotor in rotary tiller a. ‗L‘ type blade c) both A & B b. Twisted blade d) chisel plough

Description : The following types of blades are used with the rotor in rotary tiller a. ‗L‘ type blade c) both A & B b. Twisted blade d) chisel plough

Last Answer :  both A & B

It is employed on mulchers designed mainly for secondary Tillage. a. ‗L‘ type blade c) straight blade b. Twisted blade d) dics blade

Description : It is employed on mulchers designed mainly for secondary Tillage. a. ‗L‘ type blade c) straight blade b. Twisted blade d) dics blade

Last Answer : straight blade

In a packed tower, the value of HETP equals HTUOG, when the equilibrium and the operating lines are (where, HETP = height equivalent to a theoretical plate HTUOG = overall gas phase height of a transfer unit). (A) Straight (B) Parallel (C) Both (A) & (B) (D) Neither (A) nor (B

Description : In a packed tower, the value of HETP equals HTUOG, when the equilibrium and the operating lines are (where, HETP = height equivalent to a theoretical plate HTUOG = overall gas phase height of a transfer unit). (A) Straight (B) Parallel (C) Both (A) & (B) (D) Neither (A) nor (B

Last Answer : (C) Both (A) & (B)

Differentiate induced draft and forced draft cooling towers based on (i) Location of fan (ii) Corrosion of blades (iii) Efficiency (iv) Fan size

Description : Differentiate induced draft and forced draft cooling towers based on (i) Location of fan (ii) Corrosion of blades (iii) Efficiency (iv) Fan size

Last Answer : Differentiate induced draft and forced draft cooling towers based on (i) Location of fan (ii) Corrosion of blades (iii) Efficiency (iv) Fan size

What type of heat exchangers are most commonly used for a large-scale plant-cooling loop using seawater as the utility?

Description : What type of heat exchangers are most commonly used for a large-scale plant-cooling loop using seawater as the utility?

Last Answer : Commonly known as a secondary cooling loop or SECOOL, a closed loop water system is circulated through a processing plant near a sea. Process heat is transferred into the closed loop water and ... debris to clear the strainer. This method has been used for many years with great success.

In a cooling tower, water becomes cool by (A) Loosing sensible heat (B) Heat transfer to surroundings (C) Vaporisation due to heat loss to air (D) Loosing latent heat

Description : In a cooling tower, water becomes cool by (A) Loosing sensible heat (B) Heat transfer to surroundings (C) Vaporisation due to heat loss to air (D) Loosing latent heat

Last Answer : (A) Loosing sensible heat

Design of hyperbolic cooling tower standard for all cooling tower a) Mechanical draft b) Natural draft c) Both a & b d) Neither a & b

Description : Design of hyperbolic cooling tower standard for all cooling tower a) Mechanical draft b) Natural draft c) Both a & b d) Neither a & b

Last Answer : b) Natural draft

Artificial draught produced by a fan in the furnace can be controlled by the (A) Speed of the fan (B) Damper (C) Variation in the pitch of fan blades (D) All (A), (B) and (C)

Description : Artificial draught produced by a fan in the furnace can be controlled by the (A) Speed of the fan (B) Damper (C) Variation in the pitch of fan blades (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Artificial draught produced by a fan can be controlled by the (A) Speed of the fan (B) Damper (C) Variation in the pitch of the fan blades (D) All (A), (B) and (C

Description : Artificial draught produced by a fan can be controlled by the (A) Speed of the fan (B) Damper (C) Variation in the pitch of the fan blades (D) All (A), (B) and (C

Last Answer : (D) All (A), (B) and (C

Centrifugal pump is normally classified on the basis of the (A) rpm (B) Type of casing (C) Impeller blade angle (D) Number of blades in impeller

Description : Centrifugal pump is normally classified on the basis of the (A) rpm (B) Type of casing (C) Impeller blade angle (D) Number of blades in impeller

Last Answer : (B) Type of casing

Consider the following statements: A. Adam Osborne produced the first portable computer. B. Ian Wilmut created the cloned sheep. Which of the statements given above is (are) correct ? (1) A only (2) B only (3) Both A and B (4) Neither (A) nor (B)

Description : Consider the following statements: A. Adam Osborne produced the first portable computer. B. Ian Wilmut created the cloned sheep. Which of the statements given above is (are) correct ? (1) A only (2) B only (3) Both A and B (4) Neither (A) nor (B)

Last Answer : Both A and B

Mode of heat transfer involved in the cooling of air cooled internal combustion engine is (A) Conduction(B) Natural convection(C) Forced convection(D) None of these

Description : Mode of heat transfer involved in the cooling of air cooled internal combustion engine is (A) Conduction (B) Natural convection (C) Forced convection (D) None of these

Last Answer : (B) Natural convection

The cooling effect in a cooling tower cannot be increased by (A) Increasing the air velocity over the wet surfaces (B) Reducing the humidity of entering air (C) Lowering the barometric pressure (D) None of these

Description : The cooling effect in a cooling tower cannot be increased by (A) Increasing the air velocity over the wet surfaces (B) Reducing the humidity of entering air (C) Lowering the barometric pressure (D) None of these

Last Answer : (D) None of these

Which of the following parameters is not responsible for the heat loss from a hot steam carrying bare pipe surface located in a room without fans? (A) Emissivity of pipe surface (B) Diameter & length of the pipe (C) Temperature of hot pipe surface & that of air in the room (D) None of thes

Description : Which of the following parameters is not responsible for the heat loss from a hot steam carrying bare pipe surface located in a room without fans? (A) Emissivity of pipe surface (B) Diameter & length of the pipe (C) Temperature of hot pipe surface & that of air in the room (D) None of thes

Last Answer : Option D

Natural draft created by the chimney depends upon (A) Temperature of the flue gas (B) Its height (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Natural draft created by the chimney depends upon (A) Temperature of the flue gas (B) Its height (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Heat exchangers operating, when the asymptotic range is reached, (A) Provide very large heat transfer co-efficient (B) Results in making part of the heating surface inactive (C) Results in abruptly increased velocity (D) None of these

Description : Heat exchangers operating, when the asymptotic range is reached, (A) Provide very large heat transfer co-efficient (B) Results in making part of the heating surface inactive (C) Results in abruptly increased velocity (D) None of these

Last Answer : (B) Results in making part of the heating surface inactive

The noise produced by a ______ cooled machine is less as the rotor moves in a medium of smaller density. (a) air (b) hydrogen (c) either (a) or (b) (d) none of the above

Description : The noise produced by a ______ cooled machine is less as the rotor moves in a medium of smaller density. (a) air (b) hydrogen (c) either (a) or (b) (d) none of the above

Last Answer : (b) hydrogen

The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades. (A) Inlet tip of a blade curves in a direction opposite to that (B) Outlet tip of a blade curves in a direction opposite to that (C) Inlet tip of a blade is towards the direction (D) Outlet tip of a blade is towards the direction

Description : The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades. (A) Inlet tip of a blade curves in a direction opposite to that (B) Outlet tip ... Inlet tip of a blade is towards the direction (D) Outlet tip of a blade is towards the direction

Last Answer : (D) Outlet tip of a blade is towards the direction

The variation of atmospheric potential is caused due to: (A) Difference in temperature over the surface of the earth (B) Change in the density of air (C) Both (a) and (b) (D) Neither (a) nor (b)

Description : The variation of atmospheric potential is caused due to: (A) Difference in temperature over the surface of the earth (B) Change in the density of air (C) Both (a) and (b) (D) Neither (a) nor (b)

Last Answer : (C) Both (a) and (b)

Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs? (A) Enthalpy (B) Relative humidity (C) Wet bulb temperature (D) Dew point temperature

Description : Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs? (A) Enthalpy (B) Relative humidity (C) Wet bulb temperature (D) Dew point temperature

Last Answer : (D) Dew point temperature

Packed column distillation is limited to the column __________ metres. (A) Height < 6 (B) Diameter < 0.6 (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Packed column distillation is limited to the column __________ metres. (A) Height < 6 (B) Diameter < 0.6 (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Hydraulic mean depth (Dm) for a circular pipe of diameter 'D' flowing full is 0.25 D. For a circular channel, at Dm = 0.3 D, gives the condition for the maximum (A) Flow rate (B) Mean velocity (C) Both 'a' & 'b' (D) Neither 'a' nor 'b

Description : Hydraulic mean depth (Dm) for a circular pipe of diameter 'D' flowing full is 0.25 D. For a circular channel, at Dm = 0.3 D, gives the condition for the maximum (A) Flow rate (B) Mean velocity (C) Both 'a' & 'b' (D) Neither 'a' nor 'b

Last Answer : (B) Mean velocity

In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUOG __________ the absorption factor. (A) Increases with increase in (B) Is one at unity value of (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUOG __________ the absorption factor. (A) Increases with increase in (B) Is one at unity value of (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

A flight is to depart from an airport with runway 09 and 27. Surface wind is 270/05; an inversion is reported at 300 feet with turbulence and wind shear. The wind just above the inversion is 090/30. What is the safest departure procedure? a. Take-off is not possible under these conditions b. Depart on runway 09 with a tailwind c. Depart runway 27 with maximum throttle during the passage through the inversion d. Depart runway 27 with as steep an ascent as possible

Description : A flight is to depart from an airport with runway 09 and 27. Surface wind is 270/05; an  inversion is reported at 300 feet with turbulence and wind shear. The wind just above the  ... throttle during the passage through the inversion  d. Depart runway 27 with as steep an ascent as possible

Last Answer : b. Depart on runway 09 with a tailwind

A flight is to depart from an airport with runway 09 and 27. Surface wind is 270/05; an inversion is reported at 300 feet with turbulence and wind shear. The wind just above the inversion is 090/30. What is the safest departure procedure? a. Take-off is not possible under these conditions b. Depart on runway 09 with a tailwind c. Depart runway 27 with maximum throttle during the passage through the inversion d. Depart runway 27 with as steep an ascent as possible

Description : A flight is to depart from an airport with runway 09 and 27. Surface wind is 270/05; an inversion is reported at 300 feet with turbulence and wind shear. The wind just above the ... throttle during the passage through the inversion d. Depart runway 27 with as steep an ascent as possible

Last Answer : b. Depart on runway 09 with a tailwind

With increase in temperature, the leaching rate increases due to (A) Decreased liquid viscosity (B) Increased diffusivity (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : With increase in temperature, the leaching rate increases due to (A) Decreased liquid viscosity (B) Increased diffusivity (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

Power requirement of fans having constant wheel diameter varies __________ fan speed. (A) As square of (B) Directly as (C) As cube of (D) None of these

Description : Power requirement of fans having constant wheel diameter varies __________ fan speed. (A) As square of (B) Directly as (C) As cube of (D) None of these

Last Answer : (C) As cube of

In the natural draft cooling tower_________ is not required a) Fan b) tower c) Nozzle d) none of the above

Description : In the natural draft cooling tower_________ is not required a) Fan b) tower c) Nozzle d) none of the above

Last Answer : Fan