The purpose of floating head in a heat exchanger is to
(A) Avoid buckling of tubes
(B) Provide support for tubes
(C) Decrease the pressure drop
(D) Facilitate its lengthening, if needed
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 heat exchanger, floating head is provided to (A) Facilitate cleaning of the exchanger (B) Increase the heat transfer area (C) Relieve stresses caused by thermal expansion (D) Increase log mean temperature gradient
Last Answer : (C) Relieve stresses caused by thermal expansion
Description : The purpose of lateral ties in short R.C. columns is to (a) Increase the load carrying capacity of column (b) Facilitate compaction of concrete (c) Facilitate construction (d) Avoid buckling of longitudinal bars
Last Answer : (d) Avoid buckling of longitudinal bars
Description : The purpose of lateral ties in short reinforced concrete columns is to [ A ] Facilitate construction [ B ] Facilitate compaction of concrete [ C ] Increase the load carrying capacity of the columns [ D ] Avoid buckling of longitudinal bars
Last Answer : [ D ] Avoid buckling of longitudinal bars
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 : 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 : 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 purpose of providing expansion bellows in the shell of tubular exchanger is to (A) Increase the heating load (B) Impart structural strength (C) Account for the uneven expansion of shell and tube bundles (D) Facilitate increase of shell length, if needed
Last Answer : (C) Account for the uneven expansion of shell and tube bundles
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 : 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 : 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
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 : In a gas-liquid shell and tube heat exchanger, the (A) Presence of a non-condensable gas decreases the condensing film coefficient (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) 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 : 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 : 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 : 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 : A 2-4 heat exchanger involves (A) Only counter-flow of fluids (B) Only parallel-flow of fluids (C) Both counter and parallel-flow of the fluids (D) Smaller pressure drop compared to 1-2 exchanger
Last Answer : (C) Both counter and parallel-flow of the fluids
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 : 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 : 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 : 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 : To reduce the tube side pressure drop for the same flow rate, the heat exchanger recommended is (A) 1-2 heat exchanger (B) 1-1 heat exchanger (C) 3-2 heat exchanger (D) 2-4 heat exchanger
Last Answer : (B) 1-1 heat exchanger
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 : 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 : 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 : . If all the conditions and dimensions are same, then the ratio of velocity through the tubes of a double pass heat exchanger to that through the single pass heat exchanger is (A) 1 (B) 2 (C) 1/2 (D) 4
Last Answer : (B) 2
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 : 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 : Heat exchanger tubes are never made of (A) Plain carbon steel (B) Stainless steel (C) Lead (D) Copper
Last Answer : (C) Lead
Description : How can one estimate how the friction factor changes in heat exchanger tubes with a change in temperature?
Last Answer : Seider and Tate recommended the following for determine friction factors inside heat exchanger tubes with varying temperatures: First, determine the average, bulk mean temperature in the processing line. For example if ... 0.11 and for heating, it's divided by (bulk viscosity/wall viscosity)0.17.
Description : Is there a quick rule-of-thumb to estimate a gas side heat-transfer rate inside the tubes of a shell and tube heat exchanger?
Last Answer : If you need to estimate a gas heat transfer rate or see if a program is getting a reasonable gas rate, use the following: h = 75 X Sq. Root(Op. pressure/100) The operating pressure is ... will be lower for the shell side or if there is more than one exchanger. Source: Gulley Computer Associates
Description : Finned tube heat exchangers (A) Give larger area per tube (B) Use metal fins of low thermal conductivity (C) Facilitate very large temperature drop through tube wall (D) Are used for smaller heat load
Last Answer : (A) Give larger area per tube
Description : How can a firm provide a margin of safety if it cannot borrow on short notice to meet its needs? A. Maintain a low level of current assets (especially cash and marketable securities) ... the level of fixed assets (especially plant and equipment D. Lengthening the maturity schedule of financing
Last Answer : D. Lengthening the maturity schedule of financing
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 : 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 : 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 : Vent pipes are provided in a condenser to (A) Remove non-condensable gases (B) Purge the condenser (C) Facilitate easy cleaning of tubes (D) None of these
Last Answer : (A) Remove non-condensable gases
Description : Muscle relaxants can be used for which of the following? A. To facilitate intubation. B. To provide optimal surgical conditions. C. To optimize ventilator support. D. To provide sedation.
Last Answer : Answer: ABC DISCUSSION: Muscle relaxants are administered to facilitate endotracheal intubation, to provide the surgeon with optimal working conditions during anesthesia, and to optimize ... amnesia. Therefore, muscle paralysis should not be performed without sedation or general anesthesia
Description : Filter aid is used to (A) Increase the rate of filtration (B) Decrease the pressure drop (C) Increase the porosity of the cake (D) Act as a support base for the septum
Last Answer : (C) Increase the porosity of the cake
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 : 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 : When an expansion is joint needed on the shell side of a shell and tube heat exchanger?
Last Answer : A fixed tube sheet exchanger does not have provision for expansion of the tubing when there is a difference in metal temperature between the shell and tubing. When this temperature difference ... unsupported tube span. This is normally twice the baffle spacing. Source: Gulley Computer Associates
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 : 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 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
Description : 43 The purpose of providing an iron core in a transformer is to A.Provide support to windings B. Reduce hysteresis loss C. decrease the reluctance of the magnetic path D. reduce eddy current losses
Last Answer : C. Decrease the reluctance of the magnetic path
Description : Tubes are held between top and bottom tube sheets in Calandria type evaporator by keeping (A) Both the tube sheets fixed (B) Both the tube sheets floating (C) The top tube sheet floating and bottom tube sheet fixed (D) The top tube sheet fixed and the bottom tube-sheet floating
Last Answer : (A) Both the tube sheets fixed
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 : 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