Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CORREL DAY 2 > HAM > Flashcards

HAM Flashcards

1
Q

Which of the following equipment is used to convert the latent heat or sensible heat of a fluid into latent heat of vaporization of another fluid?

A

heat exchanger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Specifications of condenser or heat exchanger tubes are reported as BWG number. Condenser tubes having same BWG number have same ___ regardless of nominal diameter.

A

wall thickness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

An important parameter in heat exchanger analysis, this quantity is defined as the ratio of heat exchanger’s ability to transfer heat to the fluid’s minimum ability to absorb heat.

A

NTU

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the prime reason of using multi-pass shell-and-tube heat exchangers?

A

higher heat transfer coefficient and shorter tubes are required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which of the following correctly describes a finned-tube heat exchanger?

A

large heat exchange surface per tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Staggered configuration of bank of tubes in heat exchanger internals has a ____ pitch

A

triangular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The hot fluid in a concentric-tubes heat exchanger enters at 65℃ and leaves at 40℃, while cold fluid enters at 15℃ and leaves at 45℃. From the information given we can deduce that

A

the heat exchange operates in counterflow configuration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The hot fluid in a concentric-tubes heat exchanger enters at 65℃ and leaves at 40℃, while cold fluid enters at 15℃ and leaves at 45℃. If the heat exchanger were practical, what would be its expected effectiveness?

A

0.50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Theoretically, what is expected of a cooling tower that is designed based on approach = 0?

A

The tower is impractically high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In cooling tower design and operating, the term range refers to the

A

difference between hot and cold water temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When will the wet-bulb temperature be equal to the dry-bulb temperature for air-water vapor systems

A

when RH = 100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The portion of the moisture content of a solid material that can be removed by drying using air at constant drying conditions is called

A

free-moisture content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

A measure of evaporator performance defined as the number of kg solvent vaporized per kg steam fed to the evaporator

A

economy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The driving force in heat transfer occurring in evaporator is equal to the

A

difference between the temperature of the solution and of the steam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In a forward-feed multiple-effect evaporator units, which of the following is true
The viscosity of the liquid is highest in the first effect
The solution is transported through effects by a pump
No pump is needed to withdraw the concentrate from the last effect
Boiling point elevation is the highest in the last effect

A

Boiling point elevation is the highest in the last effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which feeding strategy in multiple-effect evaporators is most recommended to concentrate a cold viscous feed, i.e. honey?

A

backward feeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the effect of BPR in multiple-effect evaporator system?

A

reduces capacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which of the following is most likely the effect of lowering the temperature of the feed to the evaporator?

A

reduced economy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which of the following state the Duhring’s principle?

A

The boiling point elevation of an aqueous solution is proportional to the concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

The solubility of anhydrous sodium sulfate in water decreases with temperature. What is the most suitable evaporator for concentrating an aqueous solution of a material like sodium sulfate?

A

vacuum evaporator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which of the following is an example of liquid-film-controlled absorption

A

absorption of carbon dioxide in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Which of the following air-conditioning processes occurs at constant dew point temperature

A

heating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The ____ of an air-water vapor system is defined as the kg of water vapor, with partial pressure equal to its vapor pressure, contained in 1 kg of dry air.

A

saturation humidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

For air-water vapor system at low pressures, the adiabatic saturation temperature is equal to the ____.

A

wet-bulb temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

A given amount of wet air is cooled at constant dew point and constant total pressure. Which of the following is not possible to occur?

A

The enthalpy of air will increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

For air-water vapor system, when will dry-bulb temperature be equal to the wet-bulb temperature?

A

when relative humidity reaches 100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why are induced-draft towers generally preferred to other intermediate-sized water-cooling towers?

A

Induced-draft towers prevent recirculation of the humidified air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Which of the following does not occur in a water-cooling tower?

A

The humidity of the air decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Which of the following list the principles involved in water-cooling towers?

A

latent heat transfer, sensible heat transfer, mass transfer, humidification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

The equilibrium curve required in the design of the water cooling tower is a plot of

A

enthalpy of the air and temperature of the water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

In the drying of a wet solid material at constant drying conditions, the total drying is the sum of the drying time in the constant-rate period and drying time in the falling-rate period if

A

the initial free-moisture content is greater than the critical free-moisture content.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Which drying period at constant drying conditions is usually divided into two zones - the unsaturated surface drying and the internal moisture movement?

A

falling-rate period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

In some materials, the movement of moisture during drying at constant conditions in the falling-rate period is controlled by diffusion. Of the four materials listed, identify the one which most likely will not exhibit this mechanism?

clay
sand
starch
textile

A

sand

34
Q

If the rate of interphase mass transfer is high and the surface area for transfer is large, then the height of a transfer unit in the packed column is ___.

A

small

35
Q

In the design of packed columns, the diameter and the pressure drop across the packed height are estimated based on the

A

flooding velocity of the gas

36
Q

Which quantity is used as a measure of the separation effectiveness of the particular
packing material for the species being processed in the packed column?

A

HTU

37
Q

Why is the triangular pitch preferred to square pitch tube layout in shell-and-tube heat exchangers?

A

It facilitates easier cleaning of external surfaces of the tubes, resulting in lower maintenance cost.

38
Q

How will the LMTD correction factor or fudge factor change as the number of shell-passes is increased in a shell-and-tube heat exchanger?

A

increase

39
Q

The simplest type of heat exchanger is the

A

double-pipe heat exchanger.

40
Q

What is the main reason for using multi-pass heat exchangers?

A

To obtain higher U and shorter tubes

41
Q

Which one characteristic is common to most heat exchangers?

A

A solid boundary separates the hot fluid and cold fluid.

42
Q

What is the major disadvantage of the double-pipe heat exchanger?

A

low heat-transfer surface

43
Q

Which type of heat exchanger do you recommend for applications which require large heat transfer surface?

A

Double-pipe heat exchanger

44
Q

In shell-and-tube heat exchangers, baffles are usually not needed if

A

condensing vapor on the shell-side serves as the heating medium.

45
Q

In shell-and-tube heat exchangers, where must the cleaner or less corrosive fluid be placed?

A

tube-side

46
Q

In shell-and-tube heat exchangers, where must a highly viscous fluid be placed?

A

tube-side

47
Q

To avoid expensive high-pressure shells in shell-and-tube heat exchangers, high-pressure fluid should flow through ___.

A

the tubes

48
Q

In a water to air heat exchanger, it is important to place fins on the air side because

A

it effects good mixing of the gas and this promotes good heat transfer.

49
Q

What is the primary purpose of installing baffles in shell-and-tube heat exchangers?

A

To increase the convection coefficient of the shell-side fluid

50
Q

The deposition of film or scale on the surface of the heat exchanger causes all of the
following except:

Decreased overall heat-transfer coefficient
Increased resistance to heat transfer between fluids
Lowered exit temperature of the cold fluid
Lowered exit temperature of the hot fluid

A

Lowered exit temperature of the hot fluid

51
Q

Oil, flowing in the inner tube, is being heated by a saturated steam, condensing at 1.30 bars in the annular space of a double-pipe heat exchanger. The overall heat-transfer coefficient for this system is expected to be

A

closer to the value of oil-side heat transfer coefficient.

52
Q

The fouling factor, Rf, depends on which of the following: (a) operating temperature; (b) fluid velocity; and, (c) length of service?

A

a, b, and c

52
Q

The fouling factor, Rf, depends on which of the following: (a) operating temperature; (b) fluid velocity; and, (c) length of service?

A

a, b, and c

53
Q

Which of the following fluid combinations is expected to have the highest U?

A

Steam condenser (water in tubes)

54
Q

Which set of factors affect the value of the fudge factor, F?

A

Exit temperatures, inlet temperatures, and heat exchanger type

55
Q

The fudge factor, F, is a function of R and S. If either R or S is zero, then all of the following are (or may be) true except:

A

One fluid stream has negligible heat capacity

56
Q

Which of the following defines maximum possible heat-transfer rate?

A

qmax = Cmin(Th,i – Tc,i)

57
Q

Which of the following does not necessarily apply to boilers and condensers?

A

Cmin = 0

58
Q

In which double-pipe heat-exchanger flow configuration is the temperature driving force decreasing toward the outlet of the heat exchanger?

A

Parallel flow

59
Q

If the temperature change of either fluid in a shell-and-tube or cross-flow heat exchanger is negligible, then correction factor (fudge factor) for LMTD is ___.

A

1

60
Q

If the hot fluid stream is a condensing vapor, then Cr = Cmin/Cmax =

A

∞

61
Q

The product of mass flow rate and heat capacity is called the

A

heat capacity rate

62
Q

Extended surfaces are normally installed at the fluid side of the heat exchanger where

A

the convective coefficient is low

63
Q

Mean temperature difference (MTD) and LMTD have practically same numerical values for which of the following situations?

A

When driving force does not vary much

64
Q

Which of the following is an example of a compact heat exchanger?

A

Tube-plate heat exchanger

65
Q

The relation, NTU = -ln(1-ε), applies to all heat exchangers as long as

A

Cmin/Cmax = 0

66
Q

In tube bundles inside shell-and-tube heat exchangers, the shortest distance between
adjacent tubes is called the ___.

A

tube clearance

67
Q

In tube bundles inside shell-and-tube heat exchangers, the shortest center-to-center distance between adjacent tubes is called the ___.

A

tube pitch.

68
Q

Which of the following is true as regard square pitch in tube bundles in shell-and-tube heat exchangers?

A

It makes the tubes more available for external cleaning

69
Q

Which feeding strategy in multiple-effect evaporation is required if the final concentrated product is highly viscous?

A

backward feeding

70
Q

Improving the economy of an evaporator system by using multiple effect evaporator system results to

A

decreased capacity

71
Q

Which of the following evaporator types is not well suited to concentrate heat-sensitive materials?

A

Forced-circulation evaporator

72
Q

Which of the following is true as regard evaporation as a unit
operation?

A

involves the principle of decreasing the solubility of solid

73
Q

Each Duhring line indicates that

A

the BPR of a solution is proportional to the concentration of the
solution

74
Q

Which feeding strategy in multiple-effect evaporation is required if the final concentrated has a tendency to decompose at high temperature?

A

backward feeding

75
Q

Which feeding strategy in multiple-effect evaporation requires feed pump and product pump only and no pumps in between any two effects?

A

forward feeding

76
Q

Which of the following concepts, principles or terminologies is not
related to crystallization analysis and design?

A

Duhring’s law

77
Q

If all crystals in magma grow in a uniform supersaturation field and at the same temperature and if all crystals grow from birth at the rate governed by the supersaturation then, according to ΔL Law, which of the following are true: (1) All crystals are of the same type; (2) All crystals have the same growth rate; (3) Crystals grow at a rate which is proportional to size?

A

1 and 2

78
Q

Which of the following methods of accomplishes reaching supersaturation by addition of a non-solvent, which decreases the solubility of the solute?

A

drowning

79
Q

Which of the following is not assumed by the MSMPR model?

A

Efficient classification of crystal sizes in the withdrawal system

CORREL DAY 2 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions