Pick out the wrong statement. (A) The condensing film co-efficient is about 3 times lower for vertical condenser as compared to the equivalent horizontal condenser for identical situation (B) Film co-efficient for vaporisation decreases as a result of vapor binding (C) In industrial practice, sub-cooling of condensate is required, when thecondensate is a volatile liquid and is to be transferred for storage(D) Overall heat transfer co-efficient in a heat exchanger is controlled by thevalue of the film co-efficient, which is higher

Pick out the wrong statement.

(A) The condensing film co-efficient is about 3 times lower for vertical

condenser as compared to the equivalent horizontal condenser for identical

situation

(B) Film co-efficient for vaporisation decreases as a result of vapor binding

(C) In industrial practice, sub-cooling of condensate is required, when the

condensate is a volatile liquid and is to be transferred for storage

(D) Overall heat transfer co-efficient in a heat exchanger is controlled by the

value of the film co-efficient, which is higher

by

1 Answer

Answer :

(D) Overall heat transfer co-efficient in a heat exchanger is controlled by the

value of the film co-efficient, which is higher

by

Related questions

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: Option B

Description : 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 ... drop through the exchanger is desired (D) Temperature of the incoming vapor is very high

Last Answer : (B) Supersaturated

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'

Pick out the wrong statement. (A) 'Solvates' are chemical compounds formed by solute with their solvents. When water is the solvent, then it is called a 'hydrate' (B) In heat exchanger calculations (Δt) weighted is used in place of Δt, when it involves more than one sequence of heating or cooling i.e., desuperheating & condensation or condensation & sub-cooling (C) Heat transfer co-efficient during nucleate boiling is not influenced by the agitation imparted (D) In case of short tube vertical evaporators, area of central downtake is about 50 to 100% of the total tube cross-sectional area

Description : Pick out the wrong statement. (A) 'Solvates' are chemical compounds formed by solute with their solvents. When water is the solvent, then it is called a 'hydrate' (B) In heat exchanger ... vertical evaporators, area of central downtake is about 50 to 100% of the total tube cross-sectional area

Last Answer : (C) Heat transfer co-efficient during nucleate boiling is not influenced by the agitation imparted

Pick out the wrong statement. (A) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for counter flow and parallel flow can be theoretically same when any one of the fluids (hot or cold fluid) passes through the heat exchanger at constant temperature (C) In case of a 1 - 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs (D) Phase change in case of a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature

Description : Pick out the wrong statement. (A) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for ... a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature

Last Answer : (C) In case of a 1 - 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs

Steam is to be condensed in a shell and tube heat exchanger, 5 m long with a shell diameter of 1 m. Cooling water is to be used for removing the heat. Heat transfer co-efficient for the cooling water, whether on shell side or tube side is the same. The best arrangement is (A) Vertical heat exchanger with steam on tube side (B) Vertical heat exchanger with steam on shell side (C) Horizontal heat exchanger with steam on tube side (D) Horizontal heat exchanger with steam on shell side

Description : Steam is to be condensed in a shell and tube heat exchanger, 5 m long with a shell diameter of 1 m. Cooling water is to be used for removing the heat. Heat transfer co-efficient ... ) Horizontal heat exchanger with steam on tube side (D) Horizontal heat exchanger with steam on shell side

Last Answer : (B) Vertical heat exchanger with steam on shell side

Pick out the wrong statement. (A) Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient (B) In a shell and tube heat exchanger, the shell pressure drop is maximum for orifice baffles (C) S.I. unit of fouling factor is Watt/m2 .°K (D) Longitudinal fins are used in extended surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube

Description : Pick out the wrong statement. (A) Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient (B) In a shell and tube heat exchanger ... surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube

Last Answer : (C) S.I. unit of fouling factor is Watt/m2 .°K

The film co-efficient is decreased due to the presence of non-condensing gases in the vapors. The film co-efficient of superheated vapor as compared to that of saturated vapor is (A) More (B) Less (C) Some (D) Either more or less; depends on the nature of vapor

Description : The film co-efficient is decreased due to the presence of non-condensing gases in the vapors. The film co-efficient of superheated vapor as compared to that of saturated vapor is (A) More (B) Less (C) Some (D) Either more or less; depends on the nature of vapor

Last Answer : (C) Some

Pick out the wrong statement. (A) Heat transfer by radiation cannot occur across an absolute volume (B) In case of a shell and tube heat exchanger, the pressure drop through the shell is proportional to the number of times the fluid crosses the bundle between baffles (C) Propagation velocity for travel of heat radiation through vacuum is equal to the velocity of the light (D) The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same

Description : Pick out the wrong statement. (A) Heat transfer by radiation cannot occur across an absolute volume (B) In case of a shell and tube heat exchanger, the pressure drop through the shell is ... The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same

Last Answer : (A) Heat transfer by radiation cannot occur across an absolute volume

Pick out the wrong statement. (A) In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed (B) In small columns, local efficiency is larger than Murphree efficiency; in large columns local efficiency is smaller than Murphree efficiency (C) For Laminar flow over a plate of length L, the local mass transfer co￾efficient at a distance L from the leading edge is 1.5 × 10 -2m/s. Then the average mass transfer co-efficient for the plate is 2 × 10 -2m/s (D) The concentration and hydrodynamic boundary layers over a flat plate are of equal thickness, if Schmidt number is equal to unity

Description : Pick out the wrong statement. (A) In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed (B) In ... layers over a flat plate are of equal thickness, if Schmidt number is equal to unity

Last Answer : (C) For Laminar flow over a plate of length L, the local mass transfer co￾efficient at a distance L from the leading edge is 1.5 × 10 -2m/s. Then the average mass transfer co-efficient for the plate is 2 × 10 -2m/s

The film co-efficient between condensing vapour and metal wall increases with (A) Increasing temperature of the vapour (B) Decreasing temperature of the vapour (C) Increasing viscosity of the film of condensate (D) Increasing temperature drop

Description : The film co-efficient between condensing vapour and metal wall increases with (A) Increasing temperature of the vapour (B) Decreasing temperature of the vapour (C) Increasing viscosity of the film of condensate (D) Increasing temperature drop

Last Answer : (A) Increasing temperature of the vapour

Pick out the correct statement about the condensation. (A) Filmwise condensation gives a lower heat transfer rate than the dropwise condensation (B) Suitable coating or vapour additive is used to promote film wise condensation (C) If a condensing liquid does not wet the surface dropwise, even then condensation will take place on it (D) Reynolds number of condensing liquid is based on its mass flow rate

Description : Pick out the correct statement about the condensation. (A) Filmwise condensation gives a lower heat transfer rate than the dropwise condensation (B) Suitable coating or vapour additive is used to promote film ... place on it (D) Reynolds number of condensing liquid is based on its mass flow rate

Last Answer : (B) Suitable coating or vapour additive is used to promote film wise condensation

If air (a non-condensing gas) is present in a condensing vapor stream, it will __________ the condensation rate of vapor. (A) Increase (B) Decrease (C) Not affect (D) Increase the condensing film co-efficient as well as

Description : If air (a non-condensing gas) is present in a condensing vapor stream, it will __________ the condensation rate of vapor. (A) Increase (B) Decrease (C) Not affect (D) Increase the condensing film co-efficient as well as

Last Answer : (B) Decrease

In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient (A) Increases (B) Decreases (C) Is not affected (D) May increase or decrease; depends on the feed

Description : In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient (A) Increases (B) Decreases (C) Is not affected (D) May increase or decrease; depends on the feed

Last Answer : (B) Decreases

The advantage of using a 1 - 2 shell and tube heat exchanger over a 1 - 1 shell and tube heat exchanger is (A) Lower tube side pressure drop (B) Lower shell side pressure drop (C) Higher tube side heat transfer co-efficient (D) Higher shell side heat transfer co-efficient

Description : The advantage of using a 1 - 2 shell and tube heat exchanger over a 1 - 1 shell and tube heat exchanger is (A) Lower tube side pressure drop (B) Lower shell side pressure drop (C) Higher tube side heat transfer co-efficient (D) Higher shell side heat transfer co-efficient

Last Answer : (C) Higher tube side heat transfer co-efficient

For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it (A) Decreases the pressure drop (B) Decreases the outlet temperature of cooling medium (C) Increases the overall heat transfer coefficient (D) None of these

Description : For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it (A) Decreases the pressure drop (B) ... the outlet temperature of cooling medium (C) Increases the overall heat transfer coefficient (D) None of these

Last Answer : (C) Increases the overall heat transfer coefficient

Pick out the wrong statement: (A) The capacity of an evaporator is reduced by the boiling point elevation (B) Corrosive liquid is normally passed through the tubes in a shell and tube heat exchanger (C) Steam jet ejector is used for vapor compression in a thermal recompression evaporator (D) Heat sensitive materials should be concentrated in high pressure evaporators

Description : Pick out the wrong statement: (A) The capacity of an evaporator is reduced by the boiling point elevation (B) Corrosive liquid is normally passed through the tubes in a ... recompression evaporator (D) Heat sensitive materials should be concentrated in high pressure evaporators

Last Answer : (D) Heat sensitive materials should be concentrated in high pressure evaporators

If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is (A) Always less than h1 (B) Always between h1 and h2 (C) Always higher than h2 (D) Dependent on metal resistance

Description : If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is (A) Always less than h1 (B) Always between h1 and h2 (C) Always higher than h2 (D) Dependent on metal resistance

Last Answer : (B) Always between h1 and h2

. A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because (A) Total heat transfer area of all the effects is -less than that in a single effect evaporator system (B) Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect (C) Boiling point elevation in a single effect system is much higher than that in any effect in a multi-effect system (D) Heat transfer co-efficient in a single effect is much lower than that in any effect in a multi-effect system

Description : . A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because (A) Total heat transfer area of ... in a single effect is much lower than that in any effect in a multi-effect system

Last Answer : (B) Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect

Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of theoretical plate calculation for distillation column (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature

Description : Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of ... (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature

Last Answer : (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column

In a vapor-liquid contacting equipment, the overall gas phase mass transfer co-efficient (M.T.C), KG is related to individual co-efficients (KG and KL ) as (A) KG = 1/KG + m/KL (B) 1/KG = 1/KG + m/KL (C) 1/KG = 1/KL + m/KG (D) KG = 1/KL + m/KG

Description : In a vapor-liquid contacting equipment, the overall gas phase mass transfer co-efficient (M.T.C), KG is related to individual co-efficients (KG and KL ) as (A) KG = 1/KG + m/KL (B) 1/KG = 1/KG + m/KL (C) 1/KG = 1/KL + m/KG (D) KG = 1/KL + m/KG

Last Answer : (B) 1/KG = 1/KG + m/KL

The inside heat transfer co-efficient in case of turbulent flow of liquid in the tube side in a 1-2 shell and tube heat exchanger is increased by __________ times, when the number of tube passes is increased to 8. (A) 2 0.8 (B) 4 0.8 (C) 4 0.4 (D) 2 0.4

Description : The inside heat transfer co-efficient in case of turbulent flow of liquid in the tube side in a 1-2 shell and tube heat exchanger is increased by __________ times, when the number of tube passes is increased to 8. (A) 2 0.8 (B) 4 0.8 (C) 4 0.4 (D) 2 0.4

Last Answer : (B) 4 0.8

Presence of a non-condensing gas in a condensing vapour (A) Increases the rate of condensation (B) Decreases thermal resistance (C) Is desirable to increase the film co-efficient (D) None of these

Description : Presence of a non-condensing gas in a condensing vapour (A) Increases the rate of condensation (B) Decreases thermal resistance (C) Is desirable to increase the film co-efficient (D) None of these

Last Answer : (D) None of these

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

Description : 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 ... Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers

Last Answer : (A) Mechanical agitation is required, if the system has low interfacial tension

In distillation column design, the McCabe-Thiele procedure is inadequate and a Ponchan-Savarit procedure is needed, when (A) Saturated feed is not used (B) An azeotrope forms (C) The latent heat of vaporisation of the more and less volatile components are greatly different (D) A total condenser is used

Description : In distillation column design, the McCabe-Thiele procedure is inadequate and a Ponchan-Savarit procedure is needed, when (A) Saturated feed is not used (B) An azeotrope forms (C) The latent ... vaporisation of the more and less volatile components are greatly different (D) A total condenser is used

Last Answer : (D) A total condenser is used

Pick out the wrong statement. (A) For a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank reactor provides higher overall selectivity(B) For an ideal mixed reactor at steady state, the exit stream has the samecomposition as fluid within the reactor and the space time is equivalent toholding time for constant density system(C) Plug flow reactor (PFR) is always smaller than mixed reactor for allpositive reaction orders for a particular duty(D) Reaction rate does not decrease appreciably as the reaction proceeds incase of an autocatalytic reaction

Description : Pick out the wrong statement. (A) For a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank reactor provides higher overall selectivity(B) For an ideal ... D) Reaction rate does not decrease appreciably as the reaction proceeds in case of an autocatalytic reaction

Last Answer : (A) For a first order consecutive reaction, a tubular flow reactor as compared to a stirred tank reactor provides higher overall selectivity

Overall heat transfer co-efficient for cooling of hydrocarbons by water is about (A) 50 -100 Kcal/hr.m2 .°C (B) 50 -100 W/m2 .°K (C) 50 -100 BTU/hr. ft. 2°F (D) 1000 - 1500 BTU/hr. ft. 2°F

Description : Overall heat transfer co-efficient for cooling of hydrocarbons by water is about (A) 50 -100 Kcal/hr.m2 .°C (B) 50 -100 W/m2 .°K (C) 50 -100 BTU/hr. ft. 2°F (D) 1000 - 1500 BTU/hr. ft. 2°F

Last Answer : (C) 50 -100 BTU/hr. ft. 2°F

The overall mass transfer co-efficient for the absorption of SO2 in air with dilute NaOH solution can be increased substantially by (A) Increasing the gas film co-efficient(B) Increasing the liquid film co-efficient(C) Increasing the total pressure(D) Decreasing the total pressure

Description : The overall mass transfer co-efficient for the absorption of SO2 in air with dilute NaOH solution can be increased substantially by (A) Increasing the gas film co-efficient (B) Increasing the liquid film co-efficient (C) Increasing the total pressure (D) Decreasing the total pressure

Last Answer : (A) Increasing the gas film co-efficient

Out of the following four assumptions used in the derivation of theequation for LMTD[LMTD = (∆t1- ∆t2)/ln(∆t1/∆t2)], which one is subject to the largest deviationin practice ?(A) Constant overall heat transfer co-efficient.(B) Constant rate of fluid flow(C) Constant specific heat(D) No partial phase change in the system

Description : Out of the following four assumptions used in the derivation of theequation for LMTD [LMTD = (∆t1 - ∆t2 )/ln(∆t1 /∆t2 )], which one is subject to the largest deviation in practice ? (A) Constant ... (B) Constant rate of fluid flow (C) Constant specific heat (D) No partial phase change in the system

Last Answer : (B) Constant rate of fluid flow

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

Description : 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

Last Answer : (C) Increase the shell side heat transfer co-efficient

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 (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

Pick out the wrong statement. (A) In a first order reaction, A → products; the reaction becomes slower as it proceeds, because the concentration of A decreases and the rate is proportional to the concentration of A (B) Transition state theory approaches the problem of calculating reaction rates by concentrating on the idea of activated complexes (C) According to the penetration theory, the mass transfer co-efficient decreases, if the exposure time of an eddy to the solute decreases (D) If the rate of an irreversible reaction, A + B → 2C is k.CA .CB , then the reaction is always elementary

Description : Pick out the wrong statement. (A) In a first order reaction, A → products; the reaction becomes slower as it proceeds, because the concentration of A decreases and the rate is proportional to the concentration ... irreversible reaction, A + B → 2C is k.CA .CB , then the reaction is always elementary

Last Answer : (C) According to the penetration theory, the mass transfer co-efficient decreases, if the exposure time of an eddy to the solute decreases

The outlet temperature of cooling water in a heat exchanger is generally not allowed to exceed above 50°C in industrial practice mainly to avoid (A) Its evaporation loss (B) Excessive corrosion (C) Uneconomic LMTD (D) Decrease in heat exchanger efficiency

Description : The outlet temperature of cooling water in a heat exchanger is generally not allowed to exceed above 50°C in industrial practice mainly to avoid (A) Its evaporation loss (B) Excessive corrosion (C) Uneconomic LMTD (D) Decrease in heat exchanger efficiency

Last Answer : (B) Excessive corrosion

Pick out the wrong statement. (A) With decrease in feed temperature, the number of plates required for binary distillation decreases for a given ‘L/V’ ratio (B) The extraction per unit of total height for a short packed column is more effective than for a tall column, in case of liquid-liquid extraction(C) Natural draft cooling towers are made of ferroconcrete and its cross￾section is wider at the bottom(D) Vander wall adsorption is also called chemisorption

Description : Pick out the wrong statement. (A) With decrease in feed temperature, the number of plates required for binary distillation decreases for a given L/V' ratio (B) The extraction per unit ... and its cross￾section is wider at the bottom (D) Vander wall adsorption is also called chemisorption

Last Answer : (D) Vander wall adsorption is also called chemisorption

Pick out the wrong statement. (A) Mass transfer co-efficient does not account for gas-liquid diffusion (B) Diffusion co-efficient and mass transfer co-efficient are not same in any mass transfer operation

Description : Pick out the wrong statement. (A) Mass transfer co-efficient does not account for gas-liquid diffusion (B) Diffusion co-efficient and mass transfer co-efficient are not same in any mass transfer operation

Last Answer : (A) Mass transfer co-efficient does not account for gas-liquid diffusion

In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation will (A) Increase (B) Decrease (C) Remain unchanged (D) Either increase or decrease; depends on the coolant flow rate

Description : In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation ... Decrease (C) Remain unchanged (D) Either increase or decrease; depends on the coolant flow rate

Last Answer : (C) Remain unchanged

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

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

Description : 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 ... steam on shell side (D) Shell and tube heat exchanger with air on shell side and steam inside tubes

Last Answer : (B) Finned tube heat exchanger with air outside and steam inside

Which of the following is Clausius-Clapeyron Equation for vaporisation of an ideal gas under the condition that the molar volume of liquid is negligible compared to that of the vapor? (A) d ln p/dt = Hvap/RT2 (B) d ln p/dt = RT2/Hvap (C) dp/dt = RT2/Hvap (D) dp/dt = Hvap/RT2

Description : Which of the following is Clausius-Clapeyron Equation for vaporisation of an ideal gas under the condition that the molar volume of liquid is negligible compared to that of the vapor? (A) d ln p/dt = Hvap/RT2 (B) d ln p/dt = RT2/Hvap (C) dp/dt = RT2/Hvap (D) dp/dt = Hvap/RT2

Last Answer : (A) d ln p/dt = Hvap/RT2

On moving the feed line (q-line) from saturated liquid feed (vertical position) to saturated vapor feed (horizontal feed), if the slope of both the operating lines are to be increased, then it will result in (A) Greater degree of separation with a fixed number of trays (B) Increased reboiler load

Description : On moving the feed line (q-line) from saturated liquid feed (vertical position) to saturated vapor feed (horizontal feed), if the slope of both the operating lines are to be increased, then it will result in (A) Greater degree of separation with a fixed number of trays (B) Increased reboiler load

Last Answer : (C) Increased reflux ratio

Clausius-Clapeyron Equation gives accurate result, when the (A) Vapour pressure is relatively low and the temperature does not vary over wide limits (B) Vapour obeys the ideal gas law and the latent heat of vaporisation is constant (C) Volume in the liquid state is negligible compared with that in the vapour state (D) All (A), (B) and (C)

Description : Clausius-Clapeyron Equation gives accurate result, when the (A) Vapour pressure is relatively low and the temperature does not vary over wide limits (B) Vapour obeys the ideal gas law and the latent heat of ... is negligible compared with that in the vapour state (D) All (A), (B) and (C)

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

The condensing pressure due to the presence of non-condensable gases, as compared to that actually required forcondensing temperatures without non-condensable gases, (a) will be higher (b) will be lower (c) will remain unaffected (d) may be higher or lower depending upon the nature of non-condensable gases

Description : The condensing pressure due to the presence of non-condensable gases, as compared to that actually required forcondensing temperatures without non-condensable gases, (a) will be higher (b) will be ... remain unaffected (d) may be higher or lower depending upon the nature of non-condensable gases

Last Answer : Ans: a

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

Description : 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

Last Answer : (C) The largest

The heat transfer co-efficient in film type condensation is __________ that for dropwise condensation. (A) Greater than (B) Lower than (C) Is same as (D) Half

Description : The heat transfer co-efficient in film type condensation is __________ that for dropwise condensation. (A) Greater than (B) Lower than (C) Is same as (D) Half

Last Answer : (B) Lower than

Pick out the wrong statement. (A) The Reynolds analogy for mass transfer is given by Lewis relation and is applicable, when Schmidt number is one (B) Sherwood number for flow in pipes can be expressed as the ratio of the concentration gradient at wall to the overall concentration difference (C) According to film theory for equimolar counter diffusion, the mass transfer coefficient is given by DAB(B)P - 3, Q - 2 (D) The z-component of the total mass flux of a component A in binary mixture of A and B is given by - Dab'.dCA/dz

Description : Pick out the wrong statement. (A) The Reynolds analogy for mass transfer is given by Lewis relation and is applicable, when Schmidt number is one (B) Sherwood number for flow in pipes can be expressed ... flux of a component A in binary mixture of A and B is given by - Dab'.dCA/dz

Last Answer : (C) According to film theory for equimolar counter diffusion, the mass transfer coefficient is given by DAB(B)P - 3, Q - 2

Pick out the wrong statement about nucleate boiling. (A) Bubble generation is by expansion of entrapped gas/vapour at small cavities in the surface (B) Surface temperature is greater than the saturation temperature of the liquid (C) Heat transfer from the surface of the liquid is less than that in film boiling (D) The temperature is less than that of film boiling

Description : Pick out the wrong statement about nucleate boiling. (A) Bubble generation is by expansion of entrapped gas/vapour at small cavities in the surface (B) Surface temperature is greater than the saturation ... less than that in film boiling (D) The temperature is less than that of film boiling

Last Answer : (D) The temperature is less than that of film boiling

Pick out the wrong statement. (A) Angle of repose of coal increases with its increasing size (B) Specific gravity of coal increases with its increasing maturity (C) Refractive index and reflectance of coal increases with the increasing rank of coal (D) Specific heat of coal decreases with increases in the volatile matter and decrease in the C/H ratio of coal

Description : Pick out the wrong statement. (A) Angle of repose of coal increases with its increasing size (B) Specific gravity of coal increases with its increasing maturity (C) Refractive index and reflectance of ... of coal decreases with increases in the volatile matter and decrease in the C/H ratio of coal

Last Answer : (D) Specific heat of coal decreases with increases in the volatile matter and decrease in the C/H ratio of coal

Pick out the wrong statement. (A) A refrigeration cycle violates the second law of thermodynamics (B) Refrigeration cycle is normally represented by a temperature vs. entropy plot (C) In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases (D) One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW

Description : Pick out the wrong statement. (A) A refrigeration cycle violates the second law of thermodynamics (B) Refrigeration cycle is normally represented by a temperature vs. entropy plot (C) In a refrigerator, ... (D) One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW

Last Answer : (A) A refrigeration cycle violates the second law of thermodynamics

. In a shell and tube heat exchanger, the tube side heat transfer co￾efficient just at the entrance of the tube is (A) Infinity (B) Zero (C) Same as average heat transfer co-efficient for tube side (D) None of these

Description : . In a shell and tube heat exchanger, the tube side heat transfer co￾efficient just at the entrance of the tube is (A) Infinity (B) Zero (C) Same as average heat transfer co-efficient for tube side (D) None of these

Last Answer : (A) Infinity