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

1 Answer

Answer :

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

Related questions

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

Description : Pick out the wrong statement. (A) Orifice baffles are never used in a shell and tube heat exchanger (B) Pressure drop on the shell side of a heat exchanger depends upon tube pitch also

Last Answer : (A) Orifice baffles are never used in a shell and tube heat exchanger

Description : Use of transverse baffles in a shell and tube heat exchanger is done to increase the (A) Rate of heat transfer (B) Flow velocity (C) Turbulence of shell side fluid (D) All (A), (B) and (C)

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

Description : In case of a multipass shell and tube heat exchanger, the temperature drop in the fluid (A) Is inversely proportional to the resistance across which the drop occurs (B) And the wall are proportional to individual resistances (C) And the wall is not related (D) None of these

Last Answer : (B) And the wall are proportional to individual resistances

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

Description : In a shell and tube heat exchanger, the shell side fluid velocity can’t be changed by changing the (A) Tube layout (B) Tube diameter (C) Tube pitch (D) Number of baffles

Last Answer : (B) Tube diameter

Description : Baffles provided on the shell side of a shell and tube heat exchanger are meant for (A) Providing support for the tubes (B) Improving heat transfer (C) Both 'a' & 'b' (D) Preventing the fouling of tubes & stagnation of shell side fluid

Last Answer : C) Both 'a' & 'b'

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

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

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

Description : Shell side pressure drop in a shell and tube heat exchanger does not depend upon the (A) Baffle spacing & shell diameter (B) Tube diameter & pitch (C) Viscosity, density & mass velocity of shell side fluid (D) None of these

Last Answer : (D) None of these

Description : In a shell and tube heat exchanger, (A) The temperature drops in the two fluids and the wall are proportional to individual resistances (B) The temperature drop is inversely proportional to ... ) There is no relationship between temperature drop and resistance (D) The relationship is not generalised

Last Answer : (A) The temperature drops in the two fluids and the wall are proportional to individual resistances

Description : In a shell and tube heat exchanger, the height of 25 percent cut baffles is equal to (where, D = inside diameter of shell). (A) 0.25 D (B) 0.50 D (C) 0.75 D

Last Answer : (C) 0.75 D

Description : 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 ( ... in a heat exchanger is controlled by the value of the film co-efficient, which is higher

Last Answer : (D) Overall heat transfer co-efficient in a heat exchanger is controlled by the value of the film co-efficient, which is higher

Description : In a shell and tube heat exchanger, putting a longitudinal baffle across the shell, forces the shell side fluid to pass __________ through the heat exchanger. (A) Once (B) Twice (C) Thrice (D) Four times

Last Answer : (B) Twice

Description : Extremely large or small volumes of fluids are generally best routed through the shell side of a shell and tube heat exchanger, because of the (A) Less corrosion problems (B) Flexibility possible in the baffle arrangement (C) Low pressure drop (D) High heat transfer co-efficient

Last Answer : (B) Flexibility possible in the baffle arrangement

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

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

Description : The main function of baffles provided in a shell and tube heat exchanger is to (A) Facilitate the cleaning of outer tube surface (B) Enhance turbulence (C) Hold the tubes in position (D) All 'a', 'b' & 'c'

Last Answer : (B) Enhance turbulence

Description : Which of the following parameters is increased by use of finned tube in a multipass shell and tube heat exchanger? (A) Tube side pressure drop and the heat transfer rate (B) Convective heat transfer co-efficient (C) Effective tube surface area for convective heat transfer (D) All (A) (B) and (C)

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

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

Description : In a shell and tube heat exchanger, floating head is used for (A) Large temperature differentials (B) High heat transfer co-efficient (C) Low pressure drop (D) Less corrosion of tubes

Last Answer : (A) Large temperature differentials

Description : In a multipass shell and tube heat exchanger, tube side return pressure loss is equal to __________ the velocity head. (A) Twice (B) Four times (C) Square root of (D) Square of

Last Answer : (B) Four times

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

Description : Are there any alternatives to scraping a shell and tube if a capacity increase will make the pressure drop across the exchanger too large?

Last Answer : When an increase in capacity will cause excessive pressure drop, you may not have to junk the heat exchangers. A relatively inexpensive alteration is to reduce the number of tube passes. ... the exchangers in parallel or using lowfins or other special tubing. Source: Gulley Computer Associates

Description : In a shell and tube type heat exchanger, the floating tube bundle heat arrangement is used (A) In low range of temperature differences (B) In high range of temperature differences (C) Because of its low cost (D) To prevent corrosion of the tube bundles

Last Answer : (B) In high range of temperature differences

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

Last Answer : (B) d -0.2

Description : Pick out the wrong statement. (A) In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2 (B) Sherwood number in mass transfer corresponds to ... tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side

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

Description : In a shell and tube heat exchanger, square pitch compared to triangular pitch (A) Gives a higher shell side pressure drop (B) Gives a lower shell side pressure drop (C) Can pack more surface area into a shell of given diameter (D) None of these

Last Answer : (A) Gives a higher shell side pressure drop

Description : The ratio of velocity head to tube side return loss in case of a multipass shell and tube heat exchanger is (A) 2 (B) 1/2 (C) 4 (D) 1/4

Last Answer : (D) 1/4

Description : In an extended surface heat exchanger, fluid having lower co-efficient (A) Flows through the tube (B) Flows outside the tubes (C) Can flow either inside or outside the tubes (D) Should not be used as it gives very high pressure drop

Last Answer : (B) Flows outside the tubes

Description : In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side __________ the heat transfer rate. (A) Increases (B) Decreases (C) Does not affect (D) May increase or decrease, depends on the type of baffle

Last Answer : (A) Increases

Description : In a 1-1 concurrent heat exchanger, if the tube side fluid outlet temperature is equal to the shell side fluid outlet temperature, then the LMTD is (A) ∞ (B) 0 ... temperature (D) Equal to the difference between hot fluid inlet temperature and cold fluid outlet temperature

Last Answer : (B) 0

Description : Which of the following parameters of the fluid is not very important, while deciding its route in a shell and tube heat exchanger? (A) Corrosiveness & fouling characteristics (B) Pressure (C) Viscosity (D) Density

Last Answer : (D) Density

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

Description : Vibrations in the tubes of a shell and tube heat exchanger is induced due to the (A) Flow of fluid on the tube and shell sides (B) Oscillations in the flow of shell/tube sides fluid (C) Vibrations ... piping and/or supports due to external reasons (D) All (A), (B) and (C)

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

Description : Pick out the wrong statement. (A) Heat transfer from a hot body to cold body by the emission of heat waves is called radiation (B) Filmwise condensation takes place on non-wettable surfaces (C) The ... of a solution is affected by liquid head as well as boiling point elevation (D) None of these

Last Answer : (B) Filmwise condensation takes place on non-wettable surfaces

Description : For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area (A) Increases (B) Decreases (C) Remain constant (D) Passes through a maxima

Last Answer : (D) Passes through a maxima

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

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

Description : If the baffle spacing in a shell and tube heat exchanger increases, then the Reynolds number of the shell side fluid (A) Remains unchanged (B) Increases (C) Increases or decreases depending on number of shell passes (D) Decreases

Last Answer : (D) Decreases

Description : Pick out the wrong statement. (A) Bubble size increases with the dynamic viscosity of the liquid in case of nucleate pool boiling (B) Thermal conductivity of a dry material is more than ... in kg/hr in an evaporator (D) Vaporisation of organic substances in evaporator mostly causes foam formation

Last Answer : (B) Thermal conductivity of a dry material is more than that of the damp material

Description : . If a single tube pass heat exchanger is converted to two pass, then for the same flow rate, the pressure drop per unit length in tube side will (A) Increase by 1.8 times (B) Decrease by 2 2 (C) Increase by 2 16 (D) Remain unchanged

Last Answer : (C) Increase by 2 16

Description : __________ heat exchanger is the most suitable, when the temperature of shell side fluid is much higher than that of tube side. (A) Single pass, fixed tube sheet (B) U-tube (C) Three pass, fixed tube sheet (D) None of these

Last Answer : (B) U-tube

Description : Which characteristic of a fluid is not important in deciding its route in a shell and tube heat exchanger? (A) Corrosiveness (B) Fouling characteristic (C) Viscosity (D) None of these

Last Answer : (D) None of these

Description : What is a good method of minimizing shell side pressure drop in a shell and tube exchanger?

Last Answer : When shell pressure drop is critical and impingement protection is required, use rods or tube protectors in top rows instead of a plate. These create less pressure drop and better distribution ... turn of the shell stream, which causes extra pressure drop. Source: Gulley Computer Associates

Description : Hot water (0.01 m3 /min) enters the tube side of a counter current shell and tube heat exchanger at 80°C and leaves at 50°C. Cold oil (0.05 m3 /min) of density 800 kg/m3 and specific heat of ... mean temperature difference in °C is approximately (A) 32 (B) 37 (C) 45 (D) 50

Last Answer : (A) 32

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

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

Description : Pick out the wrong statement. (A) 'Green acid' is the other name of phosphoric acid produced by the reaction of phosphate rock & sulphuric acid (B) Chemically unreactive nature of ... in the manufacture of safety matches, is converted into white phosphorous by vaporisation followed by condensation

Last Answer : (C) Red phosphorous is the most reactive allotropic form of phosphorous

Description : For large heat transfer area requirement, shell and tube heat exchanger is preferred, because it (A) Occupies smaller space (B) Is more economical (C) Is easy to operate and maintain (D) All (A), (B) and (C)

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