Conduction occurs in the buffer zone for a fluid flowing through a heated pipe, only when Prandtl number is (A) 0.1 (B) > 1 (C) < 1 (D) 1

Conduction occurs in the buffer zone for a fluid flowing through a

heated pipe, only when Prandtl number is

(A) 0.1

(B) > 1

(C) < 1

(D) 1

by

1 Answer

Answer :

(A) 0.1

by

Related questions

At Pr > 1, conduction in an ordinary fluid flowing through a heated pipe is limited to the (A) Buffer zone (B) Turbulent core (C) Both (A) and (B) (D) Viscous sub-layer

Description : At Pr > 1, conduction in an ordinary fluid flowing through a heated pipe is limited to the (A) Buffer zone (B) Turbulent core (C) Both (A) and (B) (D) Viscous sub-layer

Last Answer : (D) Viscous sub-layer

Heat transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible, if the value of Prandtl number is (A) 0.2 (B) 0.4 (C) 0.6 (D) 0.8

Description : Heat transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible, if the value of Prandtl number is (A) 0.2 (B) 0.4 (C) 0.6 (D) 0.8

Last Answer : (C) 0.6

At what value of Prandtl number, conduction is negligible in the turbulent core of a fluid flowing through a heated pipe? (A) 0.5 (B) < 0.5 (C) > 0.6 (D) < 0.1

Description : At what value of Prandtl number, conduction is negligible in the turbulent core of a fluid flowing through a heated pipe? (A) 0.5 (B) < 0.5 (C) > 0.6 (D) < 0.1

Last Answer : (C) > 0.6

For __________ Prandtl number values, the heat conduction will be negligible in the buffer zone. (A) Extremely low(B) Low(C) High(D) No

Description : For __________ Prandtl number values, the heat conduction will be negligible in the buffer zone. (A) Extremely low (B) Low (C) High (D) No

Last Answer : (C) High

At what value of Prandtl number, the hydrodynamic and thermal boundary layers of a fluid flowing over a heated plate will be identical? (A) 1 (B) < 1 (C) > 1 (D) None of these

Description : At what value of Prandtl number, the hydrodynamic and thermal boundary layers of a fluid flowing over a heated plate will be identical? (A) 1 (B) < 1 (C) > 1 (D) None of these

Last Answer : (A) 1

Heat transfer in the laminar sub-layer in case of a liquid flowing through a pipe, is mostly by (A) Eddies current (B) Conduction (C) Convection (D) None of these

Description : Heat transfer in the laminar sub-layer in case of a liquid flowing through a pipe, is mostly by (A) Eddies current (B) Conduction (C) Convection (D) None of these

Last Answer : (B) Conduction

essure drop (Δp) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as (A) V1.8 (B) V-0.2 (C) V2.7 (D) V

Description : essure drop (Δp) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as (A) V1.8 (B) V-0.2 (C) V2.7 (D) V

Last Answer : (D) V

The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are (A) Re.Gz (B) Nu, Pr (C) Nu, Pr, Re (D) Nu, Gz

Description : The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are (A) Re.Gz (B) Nu, Pr (C) Nu, Pr, Re (D) Nu, Gz

Last Answer : (D) Nu, Gz

he pressure drop per unit length of pipe incurred by a fluid 'X' flowing through pipe is Δp. If another fluid 'Y' having both the specific gravity & density just double of that of fluid 'X', flows through the same pipe at the same flow rate/average velocity, then the pressure drop in this case will be (A) Δp (B) 2Δp (C) Δp 2 (D) Δp/2

Description : he pressure drop per unit length of pipe incurred by a fluid 'X' flowing through pipe is Δp. If another fluid 'Y' having both the specific gravity & density just double of that of fluid 'X', flows through the same pipe ... then the pressure drop in this case will be (A) Δp (B) 2Δp (C) Δp 2 (D) Δp/2

Last Answer : (B) 2Δp

Heat transfer co-efficient (h) for a fluid flowing inside a clean pipe is given by h = 0.023 (K/D) (DVρ/µ) 0.8 (CP .µ/k) 0.4 . This is valid for the value of NRe equal to (A) < 2100 (B) 2100-4000 (C) > 4000 (D) > 10000

Description : Heat transfer co-efficient (h) for a fluid flowing inside a clean pipe is given by h = 0.023 (K/D) (DVρ/µ) 0.8 (CP .µ/k) 0.4 . This is valid for the value of NRe equal to (A) < 2100 (B) 2100-4000 (C) > 4000 (D) > 10000

Last Answer : (D) > 10000

A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter 'd'. For a fixed mass flow rate, the tube side heat transfer co￾efficient for turbulent flow conditions is proportional to (A) d 0.8 (B) d -0.2 (C) d -1 (D) d -1.8

Description : A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter 'd'. For a fixed mass flow rate, the tube side heat transfer co￾efficient for turbulent flow conditions is proportional to (A) d 0.8 (B) d -0.2 (C) d -1 (D) d -1.8

Last Answer : (B) d -0.2

Reynolds number of a fluid flowing in a circular pipe is 10,000. What will be the Reynolds number when the fluid velocity is decreased by 30% & the pipe diameter is increased by 30%? (A) 9,100 (B) 13,000 (C) 7,000 (D) 2,550

Description : Reynolds number of a fluid flowing in a circular pipe is 10,000. What will be the Reynolds number when the fluid velocity is decreased by 30% & the pipe diameter is increased by 30%? (A) 9,100 (B) 13,000 (C) 7,000 (D) 2,550

Last Answer : (A) 9,100

Water hammer is caused, when water flowing in a pipe is suddenly brought to rest by closing the valve. The extent of pressure thus produced due to water hammer depends on the (A) Pipe length (B) Fluid velocity in the pipe (C) Time taken to close the valve (D) All (A), (B) and (C)

Description : Water hammer is caused, when water flowing in a pipe is suddenly brought to rest by closing the valve. The extent of pressure thus produced due to water hammer depends on the (A) Pipe length (B) Fluid velocity in the pipe (C) Time taken to close the valve (D) All (A), (B) and (C)

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

Shear stress in a fluid flowing in a round pipe (A) Varies parabolically across the cross-section(B) Remains constant over the cross-section(C) Is zero at the centre and varies linearly with the radius(D) Is zero at the wall and increases linearly to the centre

Description : Shear stress in a fluid flowing in a round pipe (A) Varies parabolically across the cross-section (B) Remains constant over the cross-section (C) Is zero at the centre and varies linearly with the radius (D) Is zero at the wall and increases linearly to the centre

Last Answer : (C) Is zero at the centre and varies linearly with the radius

The velocity profile for a Bingham plastic fluid flowing (under laminar conditions) in a pipe is (A) Parabolic (B) Flat (C) Flat near the wall and parabolic in the middle (D) Parabolic near the wall and flat in the middle

Description : The velocity profile for a Bingham plastic fluid flowing (under laminar conditions) in a pipe is (A) Parabolic (B) Flat (C) Flat near the wall and parabolic in the middle (D) Parabolic near the wall and flat in the middle

Last Answer : (D) Parabolic near the wall and flat in the middle

Convective heat transfer co-efficient in case of fluid flowing in tubes is not affected by the tube length/diameter ratio, if the flow is in the __________ zone. (A) Laminar (B) Transition (C) Both 'a' & 'b' (D) Highly turbulent

Description : Convective heat transfer co-efficient in case of fluid flowing in tubes is not affected by the tube length/diameter ratio, if the flow is in the __________ zone. (A) Laminar (B) Transition (C) Both 'a' & 'b' (D) Highly turbulent

Last Answer : (D) Highly turbulent

In case of laminar flow of fluid through a circular pipe, the (A) Shear stress over the cross-section is proportional to the distance from the surface of the pipe (B) Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder (C) Velocity profile varies hyperbolically and the shear stress remains constant over the cross-section (D) Average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)

Description : In case of laminar flow of fluid through a circular pipe, the (A) Shear stress over the cross-section is proportional to the distance from the surface of the pipe (B) Surface of velocity distribution is a ... occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)

Last Answer : (B) Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder

The Bernoulli's equation is based on the assumption that (A) There is no loss of energy of the liquid flowing (B) The velocity of flow is uniform across any cross-section of the pipe (C) No force except gravity acts on the fluid (D) All of the above

Description : The Bernoulli's equation is based on the assumption that (A) There is no loss of energy of the liquid flowing (B) The velocity of flow is uniform across any cross-section of the pipe (C) No force except gravity acts on the fluid (D) All of the above

Last Answer : Answer: Option D

The non-dimensional temperature gradient in a liquid at the wall of a pipe is the (A) Heat flux (B) Nusselt number (C) Prandtl number (D) Schmidt number

Description : The non-dimensional temperature gradient in a liquid at the wall of a pipe is the (A) Heat flux (B) Nusselt number (C) Prandtl number (D) Schmidt number

Last Answer : (A) Heat flux

Transition from laminar to turbulent zone in free convection heat transfer is governed by the critical value of (A) Grashoff number (B) Grashoff number & Reynolds number (C) Reynolds number (D) Grashoff number & Prandtl number

Description : Transition from laminar to turbulent zone in free convection heat transfer is governed by the critical value of (A) Grashoff number (B) Grashoff number & Reynolds number (C) Reynolds number (D) Grashoff number & Prandtl number

Last Answer : Option D

The Prandtl Pitot tube measures the (A) Velocity at a point in the flow (B) Pressure at a point (C) Average flow velocity (D) Pressure difference in pipe flow

Description : The Prandtl Pitot tube measures the (A) Velocity at a point in the flow (B) Pressure at a point (C) Average flow velocity (D) Pressure difference in pipe flow

Last Answer : (A) Velocity at a point in the flow

The Prandtl mixing length is (A) Zero at the pipe wall and is a universal constant (B) Independent of radial distance from the pipe axis (C) Independent of the shear stress (D) Useful for computing laminar flow problems

Description : The Prandtl mixing length is (A) Zero at the pipe wall and is a universal constant (B) Independent of radial distance from the pipe axis (C) Independent of the shear stress (D) Useful for computing laminar flow problems

Last Answer : (D) Useful for computing laminar flow problems

Prandtl mixing length is (A) Applicable to laminar flow problems (B) A universal constant (C) Zero at the pipe wall (D) None of these

Description : Prandtl mixing length is (A) Applicable to laminar flow problems (B) A universal constant (C) Zero at the pipe wall (D) None of these

Last Answer : (C) Zero at the pipe wall

Nusselt number is a function of Prandtl number and __________ number of fluid in natural convection heat transfer. (A) Grashoff (B) Biot (C) Stanton

Description : Nusselt number is a function of Prandtl number and __________ number of fluid in natural convection heat transfer. (A) Grashoff (B) Biot (C) Stanton

Last Answer : (A) Grashoff

The current flowing through an insulating medium is called a) Conduction b) Convection c) Radiation d) Susceptibility

Description : The current flowing through an insulating medium is called a) Conduction b) Convection c) Radiation d) Susceptibility

Last Answer : b) Convection

The hammer blow in pipes occurs when (A) There is excessive leakage in the pipe (B) The pipe bursts under high pressure of fluid(C) The flow of fluid through the pipe is suddenly brought to rest by closing of the valve (D) The flow of fluid through the pipe is gradually brought to rest by closing of the valve

Description : The hammer blow in pipes occurs when (A) There is excessive leakage in the pipe (B) The pipe bursts under high pressure of fluid (C) The flow of fluid through the pipe is suddenly brought to ... valve (D) The flow of fluid through the pipe is gradually brought to rest by closing of the valve

Last Answer : Answer: Option C

The self-cleansing velocity of water flowing through pipe lines, is A. 2 metres/sec B. 1 metre/sec C. 0.5 metre/sec D. 0.25 metre/sec

Description : The self-cleansing velocity of water flowing through pipe lines, is A. 2 metres/sec B. 1 metre/sec C. 0.5 metre/sec D. 0.25 metre/sec

Last Answer : ANS: A

Wet steam at 1 MPa flowing through a pipe is throttled to a pressure of 0.1 MPa. If the throttling temperature is110°C, What is the quality of the steam in the pipe?  a) 96%  b) 86%  c) 76%  d) 66%

Description : Wet steam at 1 MPa flowing through a pipe is throttled to a pressure of 0.1 MPa. If the throttling temperature is110°C, What is the quality of the steam in the pipe?  a) 96%  b) 86%  c) 76%  d) 66%

Last Answer : 96%

Which of the following situations can be approximated to a steady state heat transfer system? (A) A red hot steel slab (having outside surface temperature as 1300°C) exposed to the atmospheric air at 35°C (B) 10 kg of dry saturated steam at 8 kgf/cm2 flowing through a short length of stainless steel pipe exposed to atmospheric air at 35°C (C) Boiling brine kept in open vessel when the bottom surface temperature of the vessel is maintained constant at 180°C (D) A sub-cooled refrigerant liquid at 8°C flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C

Description : Which of the following situations can be approximated to a steady state heat transfer system? (A) A red hot steel slab (having outside surface temperature as 1300°C) exposed to the atmospheric air at ... flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C

Last Answer : (B) 10 kg of dry saturated steam at 8 kgf/cm2 flowing through a short length of stainless steel pipe exposed to atmospheric air at 35°C

Water is flowing at 1 m/sec through a pipe (of 10 cm I.D) with a right angle bend. The force in Newtons exerted on the bend by water is (A) 10 √2π (B) 5π/2 (C) 5 √2π (D) 5π/√2

Description : Water is flowing at 1 m/sec through a pipe (of 10 cm I.D) with a right angle bend. The force in Newtons exerted on the bend by water is (A) 10 √2π (B) 5π/2 (C) 5 √2π (D) 5π/√2

Last Answer : (B) 5π/2

A pipe of I.D. 4 m is bifurcated into two pipes of I.D. 2 m each. If the average velocity of water flowing through the main pipe is 5 m/sec, the average velocity through the bifurcated pipes is (A) 20 m/sec (B) 10 m/sec (C) 5 √2 m/sec (D) 5 m/sec

Description : A pipe of I.D. 4 m is bifurcated into two pipes of I.D. 2 m each. If the average velocity of water flowing through the main pipe is 5 m/sec, the average velocity through the bifurcated pipes is (A) 20 m/sec (B) 10 m/sec (C) 5 √2 m/sec (D) 5 m/sec

Last Answer : (B) 10 m/sec

Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube (A) Exit-fluid temperature > wall temperature (B) Exit fluid temperature < wall temperature (C) Exit fluid temperature = wall temperature (D) Graetz number > 100

Description : Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube (A) Exit-fluid temperature > wall temperature (B) Exit fluid temperature < wall temperature (C) Exit fluid temperature = wall temperature (D) Graetz number > 100

Last Answer : (C) Exit fluid temperature = wall temperature

Two fluids are flowing through two similar pipes of the same diameter. The Reynold's number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the first fluid, the pressure drop will (A) Increase (B) Decrease (C) Remain unchanged (D) Data insufficient to predict relative pressure drop

Description : Two fluids are flowing through two similar pipes of the same diameter. The Reynold's number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the ... (A) Increase (B) Decrease (C) Remain unchanged (D) Data insufficient to predict relative pressure drop

Last Answer : (B) Decrease

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

Why earth is heated by the sun through radiation and not by convection or conduction?

Description : Why earth is heated by the sun through radiation and not by convection or conduction?

Last Answer : The space between Earth and the Sun is mostly empty (emptierthan most vacuums in Earth laboratories, in any case).Convectionand conduction require the presence of atoms.

In pipe flow, heat is transferred from hot wall to the liquid by(A) Conduction only (B) Forced convection only (C) Forced convection and conduction (D) Free and forced convection

Description : In pipe flow, heat is transferred from hot wall to the liquid by(A) Conduction only (B) Forced convection only (C) Forced convection and conduction (D) Free and forced convection

Last Answer : (C) Forced convection and conduction

. In case of turbulent flow of fluid through a circular pipe, the (A) Mean flow velocity is about 0.5 times the maximum velocity (B) Velocity profile becomes flatter and flatter with increasing Reynolds number (C) Point of maximum instability exists at a distance of 2r/3 from the pipe wall (r = pipe radius) (D) Skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more

Description : . In case of turbulent flow of fluid through a circular pipe, the (A) Mean flow velocity is about 0.5 times the maximum velocity (B) Velocity profile becomes flatter and flatter with ... , shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more

Last Answer : (D) Skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more

A process stream of dilute aqueous solution flowing at the rate of10 Kg.s -1 is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s -1 . A 1 - 1 shell and tube heat exchanger is available. The best arrangement is (A) Counter flow with process stream on shell side (B) Counter flow with process stream on tube side (C) Parallel flow with process stream on shell side (D) Parallel flow with process stream on tube side

Description : A process stream of dilute aqueous solution flowing at the rate of10 Kg.s -1 is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s -1 . A 1 ... side (C) Parallel flow with process stream on shell side (D) Parallel flow with process stream on tube side

Last Answer : (A) Counter flow with process stream on shell side

03. If an incompressible liquid is continuously flowing through a pipe, the quantity of liquid passing per second is different at different sections. A) True B) False

Description : 03. If an incompressible liquid is continuously flowing through a pipe, the quantity of liquid passing per second is different at different sections. A) True B) False

Last Answer : B

The magnitude of water hammer depends upon the (A) Elastic properties of the pipe material (B) Elastic properties of the liquid flowing through the pipe (C) Speed at which the valve is closed (D) All of the above

Description : The magnitude of water hammer depends upon the (A) Elastic properties of the pipe material (B) Elastic properties of the liquid flowing through the pipe (C) Speed at which the valve is closed (D) All of the above

Last Answer : Answer: Option D

When a liquid is flowing through a pipe, the velocity of the liquid is (A) Maximum at the centre and minimum near the walls (B) Minimum at the centre and maximum near the walls (C) Zero at the centre and maximum near the walls (D) Maximum at the centre and zero near the walls

Description : When a liquid is flowing through a pipe, the velocity of the liquid is (A) Maximum at the centre and minimum near the walls (B) Minimum at the centre and maximum near the walls (C) Zero at the centre and maximum near the walls (D) Maximum at the centre and zero near the walls

Last Answer : Answer: Option A

A pitot tube is used to measure the (A) Velocity of flow at the required point in a pipe (B) Pressure difference between two points in a pipe (C) Total pressure of liquid flowing in a pipe (D) Discharge through a pipe

Description : A pitot tube is used to measure the (A) Velocity of flow at the required point in a pipe (B) Pressure difference between two points in a pipe (C) Total pressure of liquid flowing in a pipe (D) Discharge through a pipe

Last Answer : Answer: Option A

Water flowing at a 6m/s through a 60 mm pipe is suddenly channeled into a 30 mm pipe. What is the velocity in the small pipe?  a. 34m/s  b. 24m/s  c. 15m/s  d. 27m/s

Description : Water flowing at a 6m/s through a 60 mm pipe is suddenly channeled into a 30 mm pipe. What is the velocity in the small pipe?  a. 34m/s  b. 24m/s  c. 15m/s  d. 27m/s

Last Answer : 24m/s

Water is flowing through a 1 foot diameter pipe at the rate of 10ft/sec. What is the volume flow rate of water in ft³/sec?  a. 7.85  b. 6.85  c. 8.85  d. 5.85 V = Aν

Description : Water is flowing through a 1 foot diameter pipe at the rate of 10ft/sec. What is the volume flow rate of water in ft³/sec?  a. 7.85  b. 6.85  c. 8.85  d. 5.85 V = Aν

Last Answer : 7.85

If the velocity of flow as well as the diameter of the flowing pipe are respectively doubled through a pipe system in use since long, the head loss will thereafter be (a) Halved (b) Doubled (c) Increased 4 times (d) No change

Description : If the velocity of flow as well as the diameter of the flowing pipe are respectively doubled through a pipe system in use since long, the head loss will thereafter be (a) Halved (b) Doubled (c) Increased 4 times (d) No change

Last Answer : (b) Doubled

In reverberatory furnace, charge is heated mainly by (A) Conduction (B) Natural convection (C) Radiation of heat from the roof of the combustion chamber (D) None of these

Description : In reverberatory furnace, charge is heated mainly by (A) Conduction (B) Natural convection (C) Radiation of heat from the roof of the combustion chamber (D) None of these

Last Answer : (C) Radiation of heat from the roof of the combustion chamber

A fluid (µ/ρ) = 0.01 cm2 /sec is moving at critical flow condition (NRe = 2100) through a pipe of dia 3 cms. Velocity of flow is __________ cm/sec. (A) 7 (B) 700 (C) 7000 (D) 630

Description : A fluid (µ/ρ) = 0.01 cm2 /sec is moving at critical flow condition (NRe = 2100) through a pipe of dia 3 cms. Velocity of flow is __________ cm/sec. (A) 7 (B) 700 (C) 7000 (D) 630

Last Answer : (A) 7

What is the ratio of total kinetic energy of fluid passing per second to the value obtained on the basis of average velocity (for laminar flow through a circular pipe)? (A) 0.5 (B) 1 (C) 1.5 (D) 2

Description : What is the ratio of total kinetic energy of fluid passing per second to the value obtained on the basis of average velocity (for laminar flow through a circular pipe)? (A) 0.5 (B) 1 (C) 1.5 (D) 2

Last Answer : (D) 2

For turbulent flow of an incompressible fluid through a pipe, the flow rate ‘Q’ is proportional to (Δ P)n, where ΔP is the pressure drop. The value of exponent 'n' is (A) 1 (B) 0 (C) < 1 (D) > 1

Description : For turbulent flow of an incompressible fluid through a pipe, the flow rate ‘Q’ is proportional to (Δ P)n, where ΔP is the pressure drop. The value of exponent 'n' is (A) 1 (B) 0 (C) < 1 (D) > 1

Last Answer : (C) < 1

The maximum discharge through a circular channel takes place, when the depth of the fluid flow is __________ times the pipe diameter. (A) 0.25 (B) 0.5 (C) 0.66 (D) 0.95

Description : The maximum discharge through a circular channel takes place, when the depth of the fluid flow is __________ times the pipe diameter. (A) 0.25 (B) 0.5 (C) 0.66 (D) 0.95

Last Answer : (D) 0.95