# In certain heat exchanger both the fluids have identical mass flow rate-specific heat product. The hot fluid enters at 760 C and leaves at 470 C and the cold fluid entering at 260 C leaves at 550 C. The effectiveness of the heat exchanger is

1.  0.16

2.  0.58

3.  0.72

4.  1.0

4

0.58

Explanation :
No Explanation available for this question

# Heat exchanger are used in

1.  Condenses and boilers in steam plants

3.  Intercoolers and pre heaters

4.  Condenses and evaporators in refrigerators and air conditioners

5.  All of these

5

All of these

Explanation :
No Explanation available for this question

# In heat exchangers the value of logarithmic mean temperature difference (Im) should be

1.  Maximum possible

2.  Minimum possible

3.  Zero

4.  Constant

4

Maximum possible

Explanation :
No Explanation available for this question

# Value of logarithmic mean temperature difference (Im) for counter flow heat exchanger as compared to parallel flow heat exchanger is

1.  More

2.  Less

3.  Same

4.  None of these

4

More

Explanation :
No Explanation available for this question

# Automobile radiators is a heat exchanger of

1.  Counter flow type

2.  Parallel flow type

3.  Cross flow type

4.  Regenerator type

4

Cross flow type

Explanation :
No Explanation available for this question

# In the design of heat exchanger one transfer unit means

1.  Condition when change in temperature of one steam numerically equals the average driving force

2.  Section heat exchanger having surface area 1 m2

3.  Section heat exchanger having temperature drop of 10 C

4.  None of these

4

Condition when change in temperature of one steam numerically equals the average driving force

Explanation :
No Explanation available for this question

# Floating heads are provided in heat exchangers to

1.  Increase pressure drop

2.  Decrease pressure drop

3.  Regular the flow

4.  Avoid deformation of tubes due to thermal expansion

4

Avoid deformation of tubes due to thermal expansion

Explanation :
No Explanation available for this question

# Effectiveness of heat exchanger is defined as (using “i” for in and “o” for out)

1.  (thi – tho)/( tci – tco)

2.  (thi – tho)/( thi – tci)

3.  (tho – thi)/( tci – tco)

4.  (tco – thi)/( tci – tco)

4

(thi – tho)/( thi – tci)

Explanation :
No Explanation available for this question

# The logarithmic mean temperature difference (tm) is given by Where t1 and ? t2 are temperature differences between the hot and cold fluids at entrance and exit

1.  tm=Δ t1-Δt2/loge(Δ t1/ Δt2)

2.  tm=loge(Δ t1/ Δt2)/ Δ t1-Δt2

3.   tm=(Δ t1-Δt2)loge(Δ t1/ Δt2)

4.  tm=loge(Δ t1/ Δt2)/ Δ t1/Δt2

4

tm=Δ t1-Δt2/loge(Δ t1/ Δt2)

Explanation :
No Explanation available for this question

# An exchanger in who hot and cold fluids flow over heat transfer surface alternately is

1.  Direct contact exchanger

2.  Regenerator

3.  Parallel flow exchanger

4.  All of these

4