Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2.°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the_________________?

Lower pressure drop through the exchanger is desired

Higher condensing film co-efficient is desired

Condensate is corrosive in nature

Lower pressure drop through the exchanger is desired

Temperature of the incoming vapor is very high

Bulk of the convective heat transfer resistance from a hot tube surface to the fluid flowing in it, is __________________?

In the central core of the fluid

Uniformly distributed throughout the fluid

Mainly confined to a thin film of fluid near the surface

Boiling point of a solution according to Duhring’s rule is a linear function of the _____________ of water?

Boiling point (at the same pressure)

Boiling point elevation of an ideal solution_______________?

Decreases rapidly with temperature rise

Increases rapidly with temperature rise

Decreases rapidly with temperature rise

Boiling point elevation of a solution of NaOH _____________________?

Increases rapidly with temperature rise

Is almost independent of temperature

Is almost independent of pressure

Black liquor generated during paper manufacture is concentrated in a___________________?

Multiple effect evaporators followed by a crystalliser

Single effect evaporator followed by a crystalliser

Multiple effect evaporators followed by a crystalliser

Baffles in the shell side of a shell and tube heat exchanger ?

Decrease the shell side heat transfer co-efficient

Increase the cross-section of the shell side liquid

Force the liquid to flow parallel to the bank

Increase the shell side heat transfer co-efficient

Decrease the shell side heat transfer co-efficient

Baffle spacing ____________________?

Is not the same as baffle pitch

Should be less than one fifth the diameter of the shell

Should be less than the inside diameter of the shell

At constant temperature, the thermal conductivities of gases _____________ with rise in pressure?

May increase or decrease; depends on the pressure

Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube___________________?

Exit-fluid temperature > wall temperature

Exit fluid temperature < wall temperature

Exit fluid temperature = wall temperature

As per Kirchoff‟s law, the ratio of the total radiating power to the absorptivity of a body depends on the_______________?

Wavelength of monochromatic radiation

Arithmetic mean area can be used in heat transfer problem to calculate the heat flow by conduction through a cylinder which is ____________________?

Thin walled having the value of Ao Ai/< 2

Analogy between mass and heat transfer is not applicable in case of____________________?

Same velocity profile or equal eddy diffusivities

Thermal or pressure mass diffusion

Viscous heating or chemical reaction

Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is________________?

Shell and tube heat exchanger with air inside tubes and steam on shell side

Finned tube heat exchanger with air inside and steam outside

Finned tube heat exchanger with air outside and steam inside

Shell and tube heat exchanger with air inside tubes and steam on shell side

Shell and tube heat exchanger with air on shell side and steam inside tubes

Air is best heated with steam in a heat exchanger of__________________?

Double pipe type with fin on steam side

Double pipe type with fin on air side

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_______________?

Counter flow with process stream on tube side

Counter flow with process stream on shell side

Counter flow with process stream on tube side

Parallel flow with process stream on shell side

Parallel flow with process stream on tube side

A multiple effect evaporator as compared to a single effect evaporator of the same capacity has _________________?

Higher solute concentration in the product

425 + Mcqs in Chemical Heat Transfer in Chemical Engineering Page 8 McqOptions

351.	Correction is applied to LMTD for __________ flow?
A.	Parallel
B.	Counter
C.	Cross
D.	None of these
Answer» D. None of these

Discussion

352.	Convective heat transfer, in which heat is transferred by movement of warmed matter is described by___________________?
A.	Fourier’s law
B.	Newton’s law of cooling
C.	Fick’s law
D.	None of these
Answer» C. Fick’s law

Discussion

353.	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
Answer» E.

Discussion

354.	Controlling heat transfer film co-efficient is the one, which offers ______________ resistance to heat transfer?
A.	No
B.	The least
C.	The largest
D.	Lower
Answer» D. Lower

Discussion

355.	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
Answer» B. > 1

Discussion

356.	Conductance is given by (where, x = thickness, A = heat flow area, K = thermal conductivity.)?
A.	x/KA
B.	KA/x
C.	K/Ax
D.	A/Kx
Answer» C. K/Ax

Discussion

357.	Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2.°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the_________________?
A.	Higher condensing film co-efficient is desired
B.	Condensate is corrosive in nature
C.	Lower pressure drop through the exchanger is desired
D.	Temperature of the incoming vapor is very high
Answer» C. Lower pressure drop through the exchanger is desired

Discussion

358.	Colburn analogy is applicable for the value of Prandtl number from_________________?
A.	0.001 to 1
B.	0.6 to 120
C.	0.5 to 5
D.	120 to 400
Answer» C. 0.5 to 5

Discussion

359.	Circulation pump is located below the evaporator to___________________?
A.	Avoid cavitation
B.	Avoid frequent priming
C.	Create more suction head
D.	None of these
Answer» D. None of these

Discussion

360.	Choose the correct equation ?
A.	Nu = (Re) (Pr) (Gz)
B.	Nu = (Re) (Pr) (St)
C.	Nu = (Re) (Pr)
D.	Nu = (Pr) (St)
Answer» C. Nu = (Re) (Pr)

Discussion

361.	____________ chart is known as transient heat conduction chart?
A.	Dirhing’s
B.	Heisler’s
C.	Mollier’s
D.	Cox
Answer» B. Heisler’s

Discussion

362.	Bulk of the convective heat transfer resistance from a hot tube surface to the fluid flowing in it, is __________________?
A.	In the central core of the fluid
B.	Uniformly distributed throughout the fluid
C.	Mainly confined to a thin film of fluid near the surface
D.	None of these
Answer» D. None of these

Discussion

363.	Boiling point of a solution according to Duhring’s rule is a linear function of the _____________ of water?
A.	Boiling point (at the same pressure)
B.	Viscosity
C.	Density
D.	Thermal conductivity
Answer» B. Viscosity

Discussion

364.	Boiling point elevation of an ideal solution_______________?
A.	Increases rapidly with temperature rise
B.	Decreases rapidly with temperature rise
C.	In independent of pressure
D.	Both B. and C.
Answer» B. Decreases rapidly with temperature rise

Discussion

365.	Boiling point elevation of a solution of NaOH _____________________?
A.	Increases rapidly with temperature rise
B.	Is almost independent of temperature
C.	Is almost independent of pressure
D.	Both B. and C
Answer» E.

Discussion

366.	Boiling point elevation for a strong and concentrated solution is found by Duhring’s rule, which states that at the same pressure, the boiling point of a solution is a linear function of the _______________ of pure water?
A.	Boiling point
B.	Dynamic viscosity
C.	Kinematic viscosity
D.	Density
Answer» B. Dynamic viscosity

Discussion

367.	Boiling of milk in an open vessel is an example of ______________ boiling?
A.	Film
B.	Sub-cooled
C.	Saturated nucleate
D.	None of these
Answer» B. Sub-cooled

Discussion

368.	Black liquor generated during paper manufacture is concentrated in a___________________?
A.	Single effect evaporator
B.	Single effect evaporator followed by a crystalliser
C.	Multiple effect evaporator
D.	Multiple effect evaporators followed by a crystalliser
Answer» D. Multiple effect evaporators followed by a crystalliser

Discussion

369.	Baffles are provided in heat exchangers to increase the________________?
A.	Fouling factor
B.	Heat transfer area
C.	Heat transfer co-efficient
D.	Heat transfer rate
Answer» D. Heat transfer rate

Discussion

370.	Baffles in the shell side of a shell and tube heat exchanger ?
A.	Increase the cross-section of the shell side liquid
B.	Force the liquid to flow parallel to the bank
C.	Increase the shell side heat transfer co-efficient
D.	Decrease the shell side heat transfer co-efficient
Answer» D. Decrease the shell side heat transfer co-efficient

Discussion

371.	Baffles are provided in heat exchangers to____________?
A.	Remove dirt
B.	Increase heat transfer rate
C.	Reduce vibrations
D.	Reduce heat transfer rate
Answer» C. Reduce vibrations

Discussion

372.	Baffle spacing ____________________?
A.	Is not the same as baffle pitch
B.	Should be less than one fifth the diameter of the shell
C.	Should be less than the inside diameter of the shell
D.	None of these
Answer» D. None of these

Discussion

373.	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
Answer» E.

Discussion

374.	At constant temperature, the thermal conductivities of gases _____________ with rise in pressure?
A.	Decrease
B.	Increase
C.	Remain unchanged
D.	May increase or decrease; depends on the pressure
Answer» B. Increase

Discussion

375.	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
Answer» D. Graetz number > 100

Discussion

376.	As the difference between the wall temperature and bulk temperature increases, the boiling heat transfer co-efficient ?
A.	Continues to increase
B.	Continues to decrease
C.	Goes through a minimum
D.	Goes through a maximum
Answer» D. Goes through a maximum

Discussion

377.	As per Kirchoff‟s law, the ratio of the total radiating power to the absorptivity of a body depends on the_______________?
A.	Temperature of the body only
B.	Wavelength of monochromatic radiation
C.	Both A. and B.
D.	Nature of material of body
Answer» B. Wavelength of monochromatic radiation

Discussion

378.	Arithmetic mean area can be used in heat transfer problem to calculate the heat flow by conduction through a cylinder which is ____________________?
A.	Thin walled having the value of Ao Ai/< 2
B.	Thick walled
C.	Having the value of Ao/Ai > 2
D.	Both B. and C.
Answer» B. Thick walled

Discussion

379.	Analogy between mass and heat transfer is not applicable in case of____________________?
A.	Same velocity profile or equal eddy diffusivities
B.	Thermal or pressure mass diffusion
C.	Viscous heating or chemical reaction
D.	Both B. and C.
Answer» E.

Discussion

380.	An evaporator while concentrating an aqueous solution from 10 to 40% solids evaporates 30000 kg of water. The amount of solids handled by the system in kg is___________________?
A.	4000
B.	9000
C.	4600
D.	3000
Answer» B. 9000

Discussion

381.	An equipment which converts the latent or sensible heat of one fluid into the latent heat of vaporisation of another, is called a_________________?
A.	Boiler
B.	Heat exchanger
C.	Recuperator
D.	Regenerator
Answer» C. Recuperator

Discussion

382.	An ejector is used to__________________?
A.	Increase pressure
B.	Increase temperature
C.	Remove condensate
D.	None of these
Answer» E.

Discussion

383.	Among liquids, water has a comparatively high value of thermal conductivity, due to its__________________?
A.	Low density
B.	High viscosity
C.	Partial ionisation
D.	Dense structure
Answer» D. Dense structure

Discussion

384.	All analogy equations connecting friction factor and heat transfer co-efficient apply only to ___________________?
A.	Wall or skin friction
B.	Form friction
C.	Both A. and B.
D.	Turbulent flow
Answer» B. Form friction

Discussion

385.	Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is________________?
A.	Finned tube heat exchanger with air inside and steam outside
B.	Finned tube heat exchanger with air outside and steam inside
C.	Shell and tube heat exchanger with air inside tubes and steam on shell side
D.	Shell and tube heat exchanger with air on shell side and steam inside tubes
Answer» C. Shell and tube heat exchanger with air inside tubes and steam on shell side

Discussion

386.	Air is best heated with steam in a heat exchanger of__________________?
A.	Plate type
B.	Double pipe type with fin on steam side
C.	Double pipe type with fin on air side
D.	Shell and tube type
Answer» D. Shell and tube type

Discussion

387.	Agitated film evaporator is suitable for concentrating _____________ liquids?
A.	Foaming
B.	Viscous
C.	Very thin
D.	Corrosive
Answer» C. Very thin

Discussion

388.	According to Reynolds analogy, Stanton number is equal to (where, f = Fanning friction factor) ?
A.	2f
B.	f
C.	f/2
D.	f/4
Answer» D. f/4

Discussion

389.	Absorptivity and reflectivity of a perfect black body are respectively _______________?
A.	1 and 0
B.	0 and 1
C.	1 and ∞
D.	0 and 0.5
Answer» B. 0 and 1

Discussion

390.	A wall has two layers of materials A and B; each made of a different material. Both the layers have the same thickness. The thermal conductivity of material A is twice that of B. Under the equilibrium, the temperature difference across the wall is 36°C. The temperature difference across the layer A is ______________ °C?
A.	6
B.	12
C.	18
D.	24
Answer» C. 18

Discussion

391.	A _____________ surface has the maximum thermal emissivity out of the following ?
A.	Black & smooth
B.	Black & rough
C.	White & smooth
D.	White & rough
Answer» C. White & smooth

Discussion

392.	A steel sphere of radius 0.1 m at 400°K is immersed in an oil at 300°K. If the centre of the sphere reaches 350°K in 20 minutes, how long will it take for a 0.05 m radius steel sphere to reach the same temperature (at the centre) under identical conditions? Assume that the conductive heat transfer co-efficient is infinitely large ?
A.	5 minutes
B.	10 minutes
C.	20 minutes
D.	40 minutes
Answer» B. 10 minutes

Discussion

393.	A sphere of radius ‘R1’ is enclosed in a sphere of radius ‘R2’. The view (or shape) factor for radiative heat transfer of the outer sphere with respect to the inner sphere is ________________?
A.	0
B.	R2/(R1+R2)
C.	1
D.	(R1/R2)2
Answer» C. 1

Discussion

394.	A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of__________________?
A.	2
B.	20.8
C.	20.2
D.	20.5
Answer» C. 20.2

Discussion

395.	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
Answer» B. Counter flow with process stream on tube side

Discussion

396.	A perfect black body is a perfect _____________ of radiation?
A.	Absorber
B.	Emitter
C.	Both A. & B.
D.	Neither A. nor B.
Answer» D. Neither A. nor B.

Discussion

397.	A multiple effect evaporator as compared to a single effect evaporator of the same capacity has _________________?
A.	Lower heat transfer area
B.	Lower steam economy
C.	Higher steam economy
D.	Higher solute concentration in the product
Answer» D. Higher solute concentration in the product

Discussion

398.	A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is__________________?
A.	6000
B.	24000
C.	60000
D.	48000
Answer» C. 60000

Discussion

399.	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
Answer» C. 3.5

Discussion

400.	A metal ball of radius 0.1 m at a uniform temperature of 90°C is left in air at 30°C. The density and the specific heat of the metal are 3000 kg/m3 and 0.4 kJ/kg.K respectively. The heat transfer co-efficient is 50 W/m2.K Neglecting the temperature gradients inside the ball, the time taken (in hours) for the ball to cool to 60°C is_________________?
A.	555
B.	55.5
C.	0.55
D.	0.15
Answer» E.

Discussion

Explore topic-wise MCQs in Chemical Engineering.

Correction is applied to LMTD for __________ flow?

Convective heat transfer, in which heat is transferred by movement of warmed matter is described by___________________?

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?

Controlling heat transfer film co-efficient is the one, which offers ______________ resistance to heat transfer?

Conduction occurs in the buffer zone for a fluid flowing through a heated pipe, only when Prandtl number is________________?

Conductance is given by (where, x = thickness, A = heat flow area, K = thermal conductivity.)?

Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2.°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the_________________?

Colburn analogy is applicable for the value of Prandtl number from_________________?

Circulation pump is located below the evaporator to___________________?

Choose the correct equation ?

____________ chart is known as transient heat conduction chart?

Bulk of the convective heat transfer resistance from a hot tube surface to the fluid flowing in it, is __________________?

Boiling point of a solution according to Duhring’s rule is a linear function of the _____________ of water?

Boiling point elevation of an ideal solution_______________?

Boiling point elevation of a solution of NaOH _____________________?

Boiling point elevation for a strong and concentrated solution is found by Duhring’s rule, which states that at the same pressure, the boiling point of a solution is a linear function of the _______________ of pure water?

Boiling of milk in an open vessel is an example of ______________ boiling?

Black liquor generated during paper manufacture is concentrated in a___________________?

Baffles are provided in heat exchangers to increase the________________?

Baffles in the shell side of a shell and tube heat exchanger ?

Baffles are provided in heat exchangers to____________?

Baffle spacing ____________________?

At Pr > 1, conduction in an ordinary fluid flowing through a heated pipe is limited to the___________________?

At constant temperature, the thermal conductivities of gases _____________ with rise in pressure?

Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube___________________?

As the difference between the wall temperature and bulk temperature increases, the boiling heat transfer co-efficient ?

As per Kirchoff‟s law, the ratio of the total radiating power to the absorptivity of a body depends on the_______________?

Arithmetic mean area can be used in heat transfer problem to calculate the heat flow by conduction through a cylinder which is ____________________?

Analogy between mass and heat transfer is not applicable in case of____________________?

An evaporator while concentrating an aqueous solution from 10 to 40% solids evaporates 30000 kg of water. The amount of solids handled by the system in kg is___________________?

An equipment which converts the latent or sensible heat of one fluid into the latent heat of vaporisation of another, is called a_________________?

An ejector is used to__________________?

Among liquids, water has a comparatively high value of thermal conductivity, due to its__________________?

All analogy equations connecting friction factor and heat transfer co-efficient apply only to ___________________?

Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is________________?

Air is best heated with steam in a heat exchanger of__________________?

Agitated film evaporator is suitable for concentrating _____________ liquids?

According to Reynolds analogy, Stanton number is equal to (where, f = Fanning friction factor) ?

Absorptivity and reflectivity of a perfect black body are respectively _______________?

A _____________ surface has the maximum thermal emissivity out of the following ?

A sphere of radius ‘R1’ is enclosed in a sphere of radius ‘R2’. The view (or shape) factor for radiative heat transfer of the outer sphere with respect to the inner sphere is ________________?

A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of__________________?

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 perfect black body is a perfect _____________ of radiation?

A multiple effect evaporator as compared to a single effect evaporator of the same capacity has _________________?

A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is__________________?

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 ______________?