# When tc1 and tc2 are the temperature of cold fluid at entry and exit respectively and th1 and th2 are the temperatures of hot fluid at entry and exit point and cold fluid has lower heat capacity rate as compared to hot fluid, then effectiveness of the heat exchanger is given by

1.  (tc1 – tc2)/(th1 – th2)

2.  (th2 – tc2)/(th1 – tc1)

3.  (th1 – th2)/(th1 – tc1)

4.  (tc2 – tc1)/(th1 – tc1)

4

(th1 – th2)/(th1 – tc1)

Explanation :
No Explanation available for this question

# . In a parallel flow gas turbine recuperate, the maximum effectiveness is

1.  100%

2.  75%

3.  50%

4.  Between 25% and 45%

4

50\%

Explanation :
No Explanation available for this question

# Drop wise condensing usually occurs on

1.  Glazed surface

2.  Smooth surface

3.  Oil surface

4.  Coated surface

4

Oil surface

Explanation :
No Explanation available for this question

# In a heat exchange with one fluid evaporating or condensing the surface area required to least in

1.  Parallel flow

2.  Counter flow

3.  Cross flow

4.  Same in all above

4

Same in all above

Explanation :
No Explanation available for this question

# For evaporates and condenses, for the given conditions, the logarithmic mean temperature difference (LMTD) for parallel flow is

1.  Equal to that for current flow

2.  Greater than that for counter flow

3.  Smaller than that for counter flow

4.  Very much smaller than that for counter flow

4

Equal to that for current flow

Explanation :
No Explanation available for this question

# ε-NTU method is particularly useful in thermal design heat exchanges when

1.  The outlet temperature of the fluid streams is not known as a priori

2.  Outlet temperature of the fluid stream is known as a pair

3.  The Outlet temperature of the hot fluid stream is known but that of the cold fluid stream is not known as a priori

4.  Inlet temperature of the fluid streams is known as a priori

4

The outlet temperature of the fluid streams is not known as a priori

Explanation :
No Explanation available for this question

# In a shell and tube neat exchanger baffles are provided on the shell side to

1.  Prevent the stagnation of shell side fluid

2.  Improve heat transfer

3.  Provide support for tubes

4.  All of these

4

All of these

Explanation :
No Explanation available for this question

# Consider the following statements regarding condensation heat transfer: 1. For a single tube horizontal position is preferred over vertical position for better heat transfer 2. Heat transfer coefficient decreases if the vapour steam moves at high velocity 3. Condensation of steam on an oily surface is dropwise Of these statements

1.  1 and 2 are correct

2.  2 and 4 are correct

3.  1 and 3 are correct

4.  3 and 4 are correct-

4

1 and 3 are correct

Explanation :
No Explanation available for this question

# Sun’s surface at 5800 K emits radiation at a wavelength of 0.5 μ. A furnace at 3000 C will emit through a small opening radiation at a wavelength of nearly

1.  10 μ

2.  5 μ

3.  0.25 μ

4.  0.025 μ

4

5 μ

Explanation :
No Explanation available for this question

# The practice to use steam on the shell side and cooling water on the tube side. It condenses off steam power plants is because

1.  To increase overall heat transfer coefficient water side velocity can be increased if water is on the tube side

2.  Condenser can act as a storage unit for condensed steam

3.  Rate of condensation of stem is invariably smaller than the mass flow rate of cooling water

4.   It is easier to maintain vacuum on the shell side than on the tube side

4