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

1 Answer

Answer :

(C) Remain unchanged

Related questions

Description : A steam carrying pipeline is insulated with two layers of insulating materials with the inferior insulation material forming the inner part. If the two insulating layers are interchanged, the heat conducted ... ) Remain unaffected (D) May increase or decrease; depends on the thickness of each layer

Last Answer : Option C

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 : 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 : 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 : 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'

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 : 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 : 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

Description : 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

Last Answer : (C) Double pipe type with fin on air side

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

Description : LMTD for counter-flow and parallel flow heat exchanger will be the same, when the (A) Cold fluid is heated to a certain temperature by condensing steam (isothermal fluid) (B) Outlet temperature of ... temperature of hot fluid is less than the outlet temperature of the cold fluid (D) None of these

Last Answer : (A) Cold fluid is heated to a certain temperature by condensing steam (isothermal fluid)

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 : 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 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 : 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 : 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

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 : Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will (A) Increase (B) Decrease (C) Remain same (D) Data insufficient to predict pressure drop

Last Answer : (A) Increase

Description : In a heat exchanger with steam outside the tubes, a liquid gets heated to 45°C, when its flow velocity in the tubes is 2 m/s. If the flow velocity is reduced to 1 m/s, other things remaining ... than 45°C (B) More than 45°C (C) Equal to 45°C (D) Initially decreases and remains constant thereafter

Last Answer : (B) More than 45°C

Description : For a given Reynold number as d/D for an orifice increases, Cd will (where, d & D are orifice & pipe diameters respectively). (A) Increase (B) Decrease (C) Remain constant (D) Either (A) or (B); depends on other factors

Last Answer : (A) Increase

Description : Saturated steam at 1 atm is discharged from a turbine at 1200 kg/h. Superheated steam at 300 0C  and 1 atm is needed as a feed to a heat exchanger. To produce it, the turbine discharge ... amount of superheated steam at 300 0C produced and the volumetric flow rate of the  400 0C steam.

Last Answer : Solution 1. Mass balance of water 1200 + m1 = m2 ………………………………………… (1) …………………….1 mark 2. Energy balance (1200 kg/h)(2676 kJ/kg) + m1(3278 kJ/kg)

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 : The equivalent diameter for the annulus of a double pipe heat exchanger, whose inner pipe has fins on the outside is __________ compared to the same size pipes without fins. (A) More (B) Less (C) Same (D) Unpredictable

Last Answer : (B) Less

Description : The feed to fractionating column is changed from saturated vapour to saturated liquid. If the separation and reflux ratio remains unchanged, the number of ideal stages will (A) Increase (B) Decrease (C) Remain same (D) Depend on saturated boiling point; may increase or decrease

Last Answer : (A) Increase

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

Description : Pick out the wrong statement. (A) Economy of a multiple effect evaporator is not influenced by the boiling point elevation (B) Two identical cubes of iron and copper will have the same heat ... in the field of refrigeration (D) Finned tube heat exchangers are suitable for heating air by steam

Last Answer : (B) Two identical cubes of iron and copper will have the same heat content under the same conditions of temperature

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 : Two fluids are flowing through two similar pipes of the same diameter. The Reynold's number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the ... (A) Increase (B) Decrease (C) Remain unchanged (D) Data insufficient to predict relative pressure drop

Last Answer : (B) Decrease

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

Description : Which type of heat exchanger is preferred for heavy heat loads? (A) Double pipe (B) Plate fine (C) Series and parallel set of shell and tube (D) None of these

Last Answer : (C) Series and parallel set of shell and tube

Description : __________ heat exchanger is used for chilling oil to be dewaxed. (A) U-tube (B) Double pipe (C) Fixed tube

Last Answer : (B) Double pipe

Description : A concentric double pipe heat exchanger as compared to the shell and tube heat exchanger for the same heat load requires (A) Less heating surface (B) More space (C) Lower maintenance cost (D) None of these

Last Answer : (B) More space

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 : LMTD for evaporators & condensers for a given terminal parameters & set of conditions for counter-flow is equal to that for parallel flow. In such heat exchangers, with one of the fluids condensing or evaporating, the surface ... Parallel (B) Mixed (C) Counter flow (D) Same in either 'a', b' or 'c'

Last Answer : (D) Same in either 'a', b' or 'c'

Description : At constant pressure, with increase of temperature, the dew point will (A) Increase (B) Decrease (C) Remain unchanged (D) Increase/decrease; depends on the temperature

Last Answer : (A) Increase

Description : 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

Last Answer : (A) Decrease

Description : With increase in calorific value of fuels, their adiabatic flame temperatures (A) Increase (B) Decrease (C) Remain unchanged (D) May increase or decrease; depends on the quantity of products of combustion

Last Answer : (D) May increase or decrease; depends on the quantity of products of combustion

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 : 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 : In a Rankine cycle, with the maximum steam temperature being fixed from metallurgical considerations, as the boiler pressure increases (a) The condenser load will increase [IES-1997] (b) The ... The quality of turbine exhaust will increase (d) The quality of turbine exhaust will remain unchanged

Last Answer : (b) The quality of turbine exhaust will decrease 

Description : With an increase in size of tube, the rise or depression of liquid in the tube due to surface tension will (A) Decrease (B) Increase (C) Remain unchanged (D) Depend upon the characteristics of liquid

Last Answer : Answer: Option A

Description : A patient on oral anticoagulant therapy is commenced on sulfamethoxazoletrimethoprim, double-strength twice daily. One may expect to see the international normalized ratio (a) Increase (b) Decrease (c) Remain unchanged

Last Answer : Ans: A

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 : An isothermal irreversible reaction is being carried out in an ideal tubular flow reactor. The conversion in this case will __________ with decrease in space time. (A) Increase (B) Increase exponentially (C) Decrease (D) Remain unchanged

Last Answer : (C) Decrease

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

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

Description : The filtrate flow rate in constant pressure filtration (A) Continuously increases (B) Continuously decreases (C) Remain constant throughout (D) May increase or decrease; depends on the pressure

Last Answer : (B) Continuously decreases

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

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