The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is(A) 2.36(B) 4.36(C) 120.36(D) Dependent on NRe only

The Nusselt number for fully developed (both thermally and
hydrodynamically) laminar flow through a circular pipe, where the wall
heat flux is constant, is
(A) 2.36
(B) 4.36
(C) 120.36
(D) Dependent on NRe only
by

1 Answer

Answer :

(B) 4.36
by

Related questions

The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is (A) 1.66(B) 88.66 (C) 3.66 (D) Dependent on NRe only

Description : The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is (A) 1.66 (B) 88.66 (C) 3.66 (D) Dependent on NRe only

Last Answer : (C) 3.66

Nusselt number for full developed, laminar, constant property flow in a pipe at uniform heat flux is (A) 0.72 (B) 4.364 (C) 18 (D) 83

Description : Nusselt number for full developed, laminar, constant property flow in a pipe at uniform heat flux is (A) 0.72 (B) 4.364 (C) 18 (D) 83

Last Answer : (B) 4.364

Nusselt number is the ratio of the temperature gradient at the wall to (A) Temperature difference (B) Heat flux (C) That across the entire pipe (D) None of these

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Last Answer : (C) That across the entire pipe

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

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Last Answer : (A) Heat flux

Nusselt number is the ratio of the (A) Temperature gradient of the wall to that across the entire pipe (B) Temperature difference to the temperature gradient at the wall (C) Heat flux at the wall to that across the entire pipe (D) None of these

Description : Nusselt number is the ratio of the (A) Temperature gradient of the wall to that across the entire pipe (B) Temperature difference to the temperature gradient at the wall (C) Heat flux at the wall to that across the entire pipe (D) None of these

Last Answer : (C) Heat flux at the wall to that across the entire pipe

Fanning friction factor for laminar flow of fluid in a circular pipe is (A) Not a function of the roughness of pipe wall (B) Inversely proportional to Reynolds number (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Fanning friction factor for laminar flow of fluid in a circular pipe is (A) Not a function of the roughness of pipe wall (B) Inversely proportional to Reynolds number (C) Both (A) & (B) (D) Neither (A) nor (B)

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

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)

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f = 16/NRe , is valid for (A) Turbulent flow (B) Laminar flow through an open channel(C) Steady flow(D) None of these

Description : f = 16/NRe , is valid for (A) Turbulent flow (B) Laminar flow through an open channel (C) Steady flow (D) None of these

Last Answer : (D) None of these

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

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Last Answer : (C) Zero at the pipe wall

Consider the following statements in respect of steady laminar flow through a circular pipe: 1. Shear stress is zero on the central axis of the pipe 2. Discharge varies directly with the viscosity of the fluid 3. Velocity is maximum at the centre of the pipe. 4. Hydraulic gradient varies as the square of the mean velocity of flow. Which of these statements are correct? (a) 1, 2 , 3 & 4 (b) 1 & 3 only (c) 2 & 4 only (d)3 & 4 only

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Last Answer : (b) 1 & 3 only

For laminar flow of Newtonian fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to (where, μ = fluid viscosity ) (A) μ (B) 1/μ (C) √μ (D) 1/√μ

Description : For laminar flow of Newtonian fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to (where, μ = fluid viscosity ) (A) μ (B) 1/μ (C) √μ (D) 1/√μ

Last Answer : (B) 1/μ

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

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Pick out the wrong statement. (A) The form drag is dependent upon the occurrence of a wake (B) The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent) varies linearly as the radial distance (C) An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity (D) Existence of the boundary layer in fluid flow is because of viscosity of the fluid

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Last Answer : (C) An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity

For a laminar flow of fluid in a circular tube, 'h1 ' is the convective heat transfer co-efficient at velocity 'V1 '. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is (A) 1.26 h1(B) 0.794 h1(C) 0.574 h1(D) 1.741 h1

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Last Answer : (B) 0.794 h1

Nusselt number is related to the Reynolds number (Re) in turbulent & laminar flow respectively as (A) Re0.5, Re0.8 (B) Re0.8, Re-0.5 (C) Re0.8, Re0.5 (D) Re-0.8, Re0.5

Description : Nusselt number is related to the Reynolds number (Re) in turbulent & laminar flow respectively as (A) Re0.5, Re0.8 (B) Re0.8, Re-0.5 (C) Re0.8, Re0.5 (D) Re-0.8, Re0.5

Last Answer : (C) Re0.8, Re0.5

Nusselt number is related to Grashoff number (Gr) in turbulent & laminar flow respectively, in respect of free convection over a vertical flat plate as (A) Gr0.25, Gr (B) Gr0.25, Gr0.33 (C) Gr, Gr0.25 (D) Gr0.33, Gr0.25

Description : Nusselt number is related to Grashoff number (Gr) in turbulent & laminar flow respectively, in respect of free convection over a vertical flat plate as (A) Gr0.25, Gr (B) Gr0.25, Gr0.33 (C) Gr, Gr0.25 (D) Gr0.33, Gr0.25

Last Answer : Option A

The Sieder-Tate correlation for heat transfer in turbulent flow in pipe gives Nu α Re 0.8 , where, Nu is the Nusselt number and Re is the Reynolds number for the flow. Assuming that this relation is valid, the heat transfer co-efficient varies with the pipe diameter (D) as (A) D-1.8 (B) D-0.2 (C) D0.2 (D) D1.8

Description : The Sieder-Tate correlation for heat transfer in turbulent flow in pipe gives Nu α Re 0.8 , where, Nu is the Nusselt number and Re is the Reynolds number for the flow. Assuming that this relation is valid, the heat transfer co-efficient ... pipe diameter (D) as (A) D-1.8 (B) D-0.2 (C) D0.2 (D) D1.8

Last Answer : (B) D-0.2

The ratio of average fluid velocity to the maximum velocity in case of laminar flow of a Newtonian fluid in a circular pipe is (A) 0.5 (B) 1 (C) 2 (D) 0.66

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Last Answer : (A) 0.5

For laminar flow of Newtonian fluid in a circular pipe, the velocitydistribution is a function of the distance 'd' measured from the centre line ofthe pipe, and it follows a __________ relationship.(A) Logarithmic(B) Parabolic(C) Hyperbolic(D) Linear

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Pick out the wrong statement. (A) The shear stress at the pipe (dia = D, length = L) wall in case of laminar flow of Newtonian fluids is (D/4L). ∆p (B) In the equation, T. gc = k. (du/dy) n the value of 'n' for pseudoplastic and Dilatant fluid are < 1 and >1 respectively (C) Shear stress for Newtonian fluid is proportional to the rate of shear in the direction perpendicular to motion (D) With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids

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Last Answer : (D) With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids

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

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

In the complete turbulence zone (in rough pipes), the (A) Rough and smooth pipes have the same friction factor (B) Laminar film covers the roughness projections (C) Friction factor depends upon NRe only (D) Friction factor is independent of the relative roughness

Description : In the complete turbulence zone (in rough pipes), the (A) Rough and smooth pipes have the same friction factor (B) Laminar film covers the roughness projections (C) Friction factor depends upon NRe only (D) Friction factor is independent of the relative roughness

Last Answer : (D) Friction factor is independent of the relative roughness

The fluid velocity varies as the cube of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop for __________ fluid. (A) Newtonian (B) Pseudo-plastic (C) Dilatent (D) Bingham plastic

Description : The fluid velocity varies as the cube of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop for __________ fluid. (A) Newtonian (B) Pseudo-plastic (C) Dilatent (D) Bingham plastic

Last Answer : (B) Pseudo-plastic

The fluid velocity varies as the square of the cylindrical pipe diameter, in case of steady state laminar flow at constant pressure drop, for __________ fluid. (A) Newtonian (B) Dilatant (C) Pseudo-plastic (D) Non-Newtonian

Description : The fluid velocity varies as the square of the cylindrical pipe diameter, in case of steady state laminar flow at constant pressure drop, for __________ fluid. (A) Newtonian (B) Dilatant (C) Pseudo-plastic (D) Non-Newtonian

Last Answer : (A) Newtonian

The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop of __________ fluid. (A) Dilatent (B) Pseudo-plastic (C) Bingham plastic (D) Newtonian

Description : The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop of __________ fluid. (A) Dilatent (B) Pseudo-plastic (C) Bingham plastic (D) Newtonian

Last Answer : (A) Dilatent

. 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

In a boiling curve, the peak heat flux is called the __________ point. (A) Nusselt (B) Leidenfrost (C) Boiling (D) Burnout

Description : In a boiling curve, the peak heat flux is called the __________ point. (A) Nusselt (B) Leidenfrost (C) Boiling (D) Burnout

Last Answer : (D) Burnout

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

The distribution of shear stress in a stream of fluid in a circular tube is(A) Linear with radius for turbulent flow only(B) Linear with radius for laminar flow only(C) Linear with radius for both laminar & turbulent flow(D) Parabolic with radius for both laminar & turbulent flow

Description : The distribution of shear stress in a stream of fluid in a circular tube is (A) Linear with radius for turbulent flow only (B) Linear with radius for laminar flow only (C) Linear with radius for both laminar & turbulent flow (D) Parabolic with radius for both laminar & turbulent flow

Last Answer : (C) Linear with radius for both laminar & turbulent flow

Discharge in laminar flow through a pipe varies (A) As the square of the radius (B) Inversely as the pressure drop (C) Inversely as the viscosity (D) As the square of the diameter

Description : Discharge in laminar flow through a pipe varies (A) As the square of the radius (B) Inversely as the pressure drop (C) Inversely as the viscosity (D) As the square of the diameter

Last Answer : (A) As the square of the radius

The pressure drop per unit length for laminar flow of fluid through a long pipe is proportional to (where, A = cross-sectional area of the pipe & D = Diameter of the pipe) (A) A (B) D (C) 1/A (D) 1/A2

Description : The pressure drop per unit length for laminar flow of fluid through a long pipe is proportional to (where, A = cross-sectional area of the pipe & D = Diameter of the pipe) (A) A (B) D (C) 1/A (D) 1/A2

Last Answer : (C) 1/A

Transition from laminar flow to turbulent flow in fluid flow through a pipe does not depend upon the (A) Length of the pipe (B) Diameter of the pipe (C) Density of the fluid (D) Velocity of the fluid

Description : Transition from laminar flow to turbulent flow in fluid flow through a pipe does not depend upon the (A) Length of the pipe (B) Diameter of the pipe (C) Density of the fluid (D) Velocity of the fluid

Last Answer : (A) Length of the pipe

Experimental study of laminar fluid flow through a circular tube was conducted by(A) Reynolds(B) Hagen and Poiseuille(C) Pascal(D) Blake-Plummer

Description : Experimental study of laminar fluid flow through a circular tube was conducted by (A) Reynolds (B) Hagen and Poiseuille (C) Pascal (D) Blake-Plummer

Last Answer : (B) Hagen and Poiseuille

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

In a fully turbulent flow (Re > 10 5 ) in a pipe of diameter 'd', for a constant pressure gradient, the dependence of volumetric flow rate of an incompressible fluid is (A) d(B) d2(C) d2.5(D) d

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Last Answer : (C) d 2.5

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

For turbulent flow in smooth circular pipe, the velocity distribution is a function of the distance 'd' measured from the wall of the pipe and the friction velocity 'v', and it follows a __________ relationship. (A) Logarithmic (B) Linear (C) Hyperbolic (D) Parabolic

Description : For turbulent flow in smooth circular pipe, the velocity distribution is a function of the distance 'd' measured from the wall of the pipe and the friction velocity 'v', and it follows a __________ relationship. (A) Logarithmic (B) Linear (C) Hyperbolic (D) Parabolic

Last Answer : (A) Logarithmic

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

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

When the pipe Reynold's number is 6000, the flow is generally (A) Viscous(B) Laminar(C) Turbulent(D) Transition

Description : When the pipe Reynold's number is 6000, the flow is generally (A) Viscous (B) Laminar (C) Turbulent (D) Transition

Last Answer : (C) Turbulent

In turbulent flow, a rough pipe has the same friction factor as a smooth pipe (A) In the zone of complete turbulence (B) When the roughness projections are much smaller than the thickness of the laminar film (C) Everywhere in the transition zone (D) When the friction factor is independent of the Reynold's number

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Last Answer : (B) When the roughness projections are much smaller than the thickness of the laminar film

Pick out the wrong statement. (A) Mechanical agitation is required, if the system has low interfacial tension (B) Sieve tray towers are generally used for systems having low interfacial tension (C) When Henry's law constant is very small, then the mass transfer rate is controlled by the gas film resistance (D) Taylor-Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers

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Assuming flow to be laminar, if the diameter of the pipe is halved, then the pressure drop will (A) Increase (B) Decrease (C) Remain same (D) Be quadrupled

Description : Assuming flow to be laminar, if the diameter of the pipe is halved, then the pressure drop will (A) Increase (B) Decrease (C) Remain same (D) Be quadrupled

Last Answer : (A) Increase

For laminar flow of a shear thinning liquid in a pipe, if the volumetric flow rate is doubled, the pressure gradient will increase by a factor of (A) 2 (B) < 2 (C) > 2 (D) 1/2

Description : For laminar flow of a shear thinning liquid in a pipe, if the volumetric flow rate is doubled, the pressure gradient will increase by a factor of (A) 2 (B) < 2 (C) > 2 (D) 1/2

Last Answer : (A) 2

Friction factor for a hydraulically smooth pipe at NRe = 2100 is f1 . If the pipe is further smoothened (i.e., roughness is reduced), the friction factor at the same value of NRe , will (A) Increase (B) Decrease (C) Remain unchanged (D) Increase or decrease depending on the pipe material

Description : Friction factor for a hydraulically smooth pipe at NRe = 2100 is f1 . If the pipe is further smoothened (i.e., roughness is reduced), the friction factor at the same value of NRe , will (A) Increase (B) Decrease (C) Remain unchanged (D) Increase or decrease depending on the pipe material

Last Answer : (A) Increase

What is the value of Fanning friction factor f ' for smooth pipe at NRe = 10 6 approximately? (A) 0.003 (B) 0.01 (C) 0.1(D) 0.3

Description : What is the value of Fanning friction factor f ' for smooth pipe at NRe = 10 6 approximately? (A) 0.003 (B) 0.01 (C) 0.1 (D) 0.3

Last Answer : (A) 0.003

05. The flow in a pipe is laminar, when Reynold number is less than 2000. A) True B) False

Description : 05. The flow in a pipe is laminar, when Reynold number is less than 2000. A) True B) False

Last Answer : A

The flow in a pipe is neither laminar nor turbulent when Reynold number is (A) Less than 2000 (B) Between 2000 and 2800 (C) More than 2800 (D) None of these

Description : The flow in a pipe is neither laminar nor turbulent when Reynold number is (A) Less than 2000 (B) Between 2000 and 2800 (C) More than 2800 (D) None of these

Last Answer : Answer: Option B