D2L Assignment

Question 1

which flow arrangement will the two fluid temps approach eachother and reach equilibrium somewhere between two starting temps?

Answer 1

parallel flow

Question 2

which flow arrangement is it possible for each fluid to reach inlet temperature of the opposing fluid given enough time?

Answer 2

Counter Flow

Question 3

which flow path arrangement has the greatest efficiency?

Answer 3

Counter Flow

Question 4

what is the purpose of the fins on a finned tube heat exchanger?

Answer 4

To increase surface area!

Question 5

which of the following heat exchanger designs allows surface area and capacity to be increased?

Answer 5

plate exchanger

Question 6

what is the major benefit of the spiral heat exchanger?

Answer 6

turbulent flow and large surface area

Question 7

how do cooling towers lower the temperature of process water?

Answer 7

evaporation of parts of the water

Question 8

what is the purpose of the zinc anodes in a shell and tube heat exchanger?

Answer 8

to prevent galvanic corrosion of exchanger materials

Question 9

what is the purpose of cooling tower mist eliminators?

Answer 9

to reduce water losses

Question 10

which type of heat exchanger baffle is used to reduce erosion damage cause by high velocity fluids?

Answer 10

impingement baffle

Question 11

what is the purpose of segmental or disc and doughnut baffles?

Answer 11

to prevent dead bypass areas and support the tube bundle

Question 12

how many longitudinal shell side baffles are required to achieve four passes of shell side fluid?

Answer 12

3 longitudinal shell side baffles

Question 13

how many passes does the tube side fluid make if the channel head of a fix tube exchanger has two baffles and the rear has one ?

Answer 13

the tube side would make 4 passes

Question 14

which of the following shell and tube exchanger designs is limited to flushing or chemical cleaning of the shell side?

Answer 14

fixed tubed sheet is limited

Question 15

what is the reason for using a “ floating head” design?

Answer 15

to eliminate thermal stresses

Question 16

in which of the following heat exchanger is it most difficult to clean the TUBE SIDE surfaces ?

Answer 16

u-tube exchanger ( due to the dirty little bend )

Question 17

which of the following heat exchangers is most likely to suffer damage due to thermal stress?

Answer 17

fixed tube exchanger

Question 18

which of the following heat exchanger designs is used in applications where mixing of the tube side and shell side fluids must be prevented?

Answer 18

double tube sheet

( double the protection;) )

Question 19

which of the following properties is of primary importance for materials used in heat exchanger construction?

Answer 19

high thermal conductivity

Question 20

as a general rule’ which fluid should be on the “ tube side” of a u tube exchanger?

Answer 20

clean fluid
(as it’s hard to clean the bend of the inside of the tubes)

Question 21

which of these are indications of heat exchanger fouling ?

Answer 21

a drop in efficiency and an increased pressure drop

Question 22

which methods of cleaning are suitable for tubes?

Answer 22

hot wash oil
mechanical
chemical
high pressure wate

Question 23

how should a tube bundle be supported when it’s lifted?

Answer 23

under tube sheet and baffles

Question 24

what pressure is used when hydrostatic testing a heat exchanger for leaks?

Answer 24

1.5x it’s working pressure

Question 25

how many passes are on the dirty tube side of the heat exchanger below?

Answer 25

2