jH factor for heat transfer depends upon the __________ number. (A) Biot (B) Nusselt (C) Reynolds (D) Prandtl

jH factor for heat transfer depends upon the __________ number.
(A) Biot
(B) Nusselt
(C) Reynolds
(D) Prandtl
by

1 Answer

Answer :

(C) Reynolds
by

Related questions

jH factor for heat transfer is not a function of the __________ number. (A) Reynolds (B) Nusselt (C) Grashoff (D) Both (B) & (C)

Description : jH factor for heat transfer is not a function of the __________ number. (A) Reynolds (B) Nusselt (C) Grashoff (D) Both (B) & (C)

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

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

Nusselt number (for forced convection heat transfer) is a function of the __________ number. (A) Prandtl (B) Reynolds (C) Both (A) & (B) (D) Neither (A) nor (B)

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

Pick out the wrong statement pertaining to the analogy between equations of heat and mass transfer operations. (A) Sherwood number in mass transfer is analogous to Nusselt number in heat transfer (B) Prandtl number in heat transfer is analogous to Schmidt number in mass transfer (C) Reynolds number in mass transfer is analogous to Grashoff number in heat transfer (D) Reynolds number remains the same in both heat and mass transfer

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Nusselt number/Biot number varies (A) Inversely with thermal conductivity (B) Directly with heat transfer co-efficient (C) Directly with thermal conductivity (D) Inversely with the dimension of the solid

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Last Answer : (C) Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger

The dimensionless group in mass transfer that is equivalent to Prandtl number in heat transfer is (A) Nusselt number (B) Sherwood number (C) Schmidt number (D) Stanton numbe

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Critical value of the __________ number governs the transition from laminar to turbulent flow in free convection heat transfer. (A) Grashoff (B) Reynolds (C) Both 'a' & 'b' (D) Prandtl & Grashoff

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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

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Last Answer : (B) D-0.2

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

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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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Pick out the wrong statement. (A) Fluid movement under the influence of buoyant forces resulting from change in density takes place in case of natural convection (B) The ratio NNu /NRe . Npr is called the Stanton number (C) The Peclet number is a measure of the ratio of energy transport by convection to that by conduction (D) The Colburn jH factor for heat transfer is given by Nst Npr

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Last Answer : (D) The Colburn jH factor for heat transfer is given by Nst Npr

The ratio of momentum diffusivity to thermal diffusivity is the __________ number. (A) Prandtl (B) Nusselt (C) Stanton (D) Grashoff

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The ratio of kinematic viscosity to thermal diffusivity is called the __________ number. (A) Peclet (B) Prandtl (C) Stanton (D) Nusselt

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Cpµ/K is termed as the __________ number. (A) Grashoff (B) Nusselt (C) Prandtl (D) Stanton

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Pick out the wrong statement: (A) Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer (B) Blowers develop a maximum pressure of 2 atmospheres (C) Friction losses in pipe fittings are generally expressed in terms of velocity heads (D) Fanning friction factor in case of turbulent flow of liquids in pipe depends upon relative roughness & Reynolds number

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The hydrodynamic and thermal boundary layers will merge, when (A) Prandtl number is one (B) Schmidt number tends to infinity (C) Nusselt number tends to infinity (D) Archimedes number is greater than 10000

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The equation, Nst = (f/2)/[1 + 5 (Npr - 1) √(f/2)], corresponds to __________ analogy. (A) Von-Karman (B) Reynolds (C) Colburn (D) Prandtl

Description : The equation, Nst = (f/2)/[1 + 5 (Npr - 1) √(f/2)], corresponds to __________ analogy. (A) Von-Karman (B) Reynolds (C) Colburn (D) Prandtl

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The equation, (NSt × N2/3 Pr ) = f/2, is the __________ analogy. (A) Colburn (B) Reynolds (C) Prandtl (D) None of these

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Corresponding to Nusselt number in heat transfer, the dimensionless group in mass transfer is the __________ number. (A) Sherwood (B) Schmidt (C) Peclet (D) Stanton

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Last Answer : (A) Sherwood

Give expression for the following and explain the terms involved. (i) Nusselt number (ii) Prandtl number

Description : Give expression for the following and explain the terms involved. (i) Nusselt number (ii) Prandtl number

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In which mode of heat transfer, the Biot number is important? (A) Transient heat conduction (B) Natural convection (C) Forced convection (D) Radiation

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A metal wire of 0.01 m dia and thermal conductivity 200 W/m.K is exposed to a fluid stream with a convective heat transfer coefficient of 100 W/m2 .K. The Biot number is (A) 5.6 (B) 0.025 (C) 3.5 (D) 0.0035

Description : A metal wire of 0.01 m dia and thermal conductivity 200 W/m.K is exposed to a fluid stream with a convective heat transfer coefficient of 100 W/m2 .K. The Biot number is (A) 5.6 (B) 0.025 (C) 3.5 (D) 0.0035

Last Answer : (B) 0.025

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

Corresponding to Prandtl number in heat transfer, the dimensionless group in mass transfer is the __________ number. (A) Schmidt (B) Sherwood (C) Peclet (D) Stanton

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Prandtl and Reynold's analogies are identical for Prandtl number value of (A) 0 (B) 0.5 (C) 1 (D) 5

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Which of the following is unimportant in forced convection? (A) Reynolds number (B) Prandtl number (C) Grashoff number (D) None of these

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Last Answer : (C) Grashoff number

Prandtl and Reynolds analogy are same, when Prandtl number is (A) 0.5 (B) 1 (C) > 2 (D) 1.5

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Natural convection is characterised by (A) Grashoff number (B) Peclet number (C) Reynolds number (D) Prandtl number

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Which of the following is concerned with both heat and mass transfer? (A) Lewis relationship (B) Nusselt number (C) Kutateladze number (D) Froude number

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The rate of heat transfer is a product of overall heat transfer co￾efficient, the difference in temperature and the (A) Heating volume (B) Heat transfer area (C) Nusselt number (D) None of these

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Value of Nusselt number [Nu = (hD/k)] for the heat transfer byconduction from a droplet or a spherical particle to a surrounding stagnant film is (A) 0.5 (B) 2 (C) 10 (D) 100

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For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as (A) Re 0.33 (B) Re 0.53 (C) Re 0.83 (D) Re

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Which of the following forced convection heat transfer equation accounts for the liquid viscosity effect for viscous liquids? (A) Dittus-Boelter equation (B) Sieder-Tate equation (C) Nusselt equation (D) None of these

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Which of the following plays an important role in problems of simultaneous heat and mass transfer?(A) Lewis number (B) Schmidt number (C) Prandtl number (D) Sherwood number

Description : Which of the following plays an important role in problems of simultaneous heat and mass transfer (A) Lewis number (B) Schmidt number (C) Prandtl number (D) Sherwood number

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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

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The friction factor for turbulent flow in a hydraulically smooth pipe (A) Depends only on Reynolds number (B) Does not depend on Reynolds number (C) Depends on the roughness (D) None of these

Description : The friction factor for turbulent flow in a hydraulically smooth pipe (A) Depends only on Reynolds number (B) Does not depend on Reynolds number (C) Depends on the roughness (D) None of these

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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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With the increase of temperature, the Col-burn jH factor (A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depending on temperature

Description : With the increase of temperature, the Col-burn jH factor (A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depending on temperature

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JD factor for mass transfer is a function of Reynolds number. Mass transfer by molecular diffusion from a single drop to surrounding still air is given by (A) Nsh = 2 (B) Nst = 2 (C) Nsc = 2 (D) None of these

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

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The rate of heat transfer from a vertical plate by natural convection depends upon the temperature differences (ΔT) between wall and outside bulk. The proportionality is given as (A) (ΔT) 1/4 (B) (ΔT) 1/2 (C) (ΔT) 5/4 (D) (ΔT) 3/4

Description : The rate of heat transfer from a vertical plate by natural convection depends upon the temperature differences (ΔT) between wall and outside bulk. The proportionality is given as (A) (ΔT) 1/4 (B) (ΔT) 1/2 (C) (ΔT) 5/4 (D) (ΔT) 3/4

Last Answer : (D) (ΔT) 3/4

Crystal size in a continuous crystalliser depends upon the (A) Rate of heat transfer (B) Degree of turbulence (C) Degree of super-saturation (D) All (A), (B) and (C)

Description : Crystal size in a continuous crystalliser depends upon the (A) Rate of heat transfer (B) Degree of turbulence (C) Degree of super-saturation (D) All (A), (B) and (C)

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

Economy of a multiple effect evaporator depends upon the (A) Heat balance consideration (B) Rate of heat transfer (C) Both (A) and (B) (D) Neither (A) nor (B

Description : Economy of a multiple effect evaporator depends upon the (A) Heat balance consideration (B) Rate of heat transfer (C) Both (A) and (B) (D) Neither (A) nor (B

Last Answer : (A) Heat balance consideration

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

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Heat transfer co-efficient (h1 ) for liquids increases with (A) Increasing temperature (B) Decreasing temperature (C) Decreasing Reynolds number (D) None of these

Description : Heat transfer co-efficient (h1 ) for liquids increases with (A) Increasing temperature (B) Decreasing temperature (C) Decreasing Reynolds number (D) None of these

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The Dittus-Boelter equation for convective heat transfer [(i.e. h = 0.023 (K/D) (Re) 0.8 (Pr) 0.4 ] cannot be used for (A) Low Reynold's number (B) Very low Grashoff number (C) Molten metals (D) All (A), (B) and (C)

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

When the ratio of the Grashoff number and to the square of Reynolds number is one, the dominant mechanism of heat transfer is: (A) Free convection (B) Entry length problem in laminar forced conduction (developing thermal boundary layer) (C) Mixed convection (both free and forced) (D) Forced convection

Description : When the ratio of the Grashoff number and to the square of Reynolds number is one, the dominant mechanism of heat transfer is: (A) Free convection (B) Entry length problem in laminar forced ... (developing thermal boundary layer) (C) Mixed convection (both free and forced) (D) Forced convection

Last Answer : (C) Mixed convection (both free and forced)

Heat transfer co-efficient equation for forced convection, Nu = 0.023 Re 0.8 . Pr n , is not valid, if the value of (A) n = 0.4 is used for heating (B) n = 0.3 is used for cooling (C) Reynolds number for the flow involved is > 10000 (D) Reynolds number for the flow involved is < 2100

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Last Answer : (D) Reynolds number for the flow involved is < 2100