ESE ME 2018: Heat Transfer Achievers National Test for ESE & GATE ME Exams

Question 1

With reference to the below figure, the shape factor between 1 and 2 is

Question 2

For the radation between two infinite parallel planes of emissivity

and

respectively, which one of the following is the following is the following is the expression for emissity factor?

Question 3

μ

If a body is at 2000 K, the wavelength at which the body emits maximum amount of radiation is

Question 4

When a liquid flows through a tube with sub-cooled or saturated boiling. What is the process known?

Question 5

In spite of large heat transfer coefficient in boiling liquids, cavities are used advantageously when the entire surface is exposed to

Question 6

The ‘NTU’ (Number of transfer Units) in a heat exchanger is given by which one of the following?

where, U = Overall heat transfer coefficient
C = Heat capacity
E = Effectiveness
A = Heat exchange area

Question 7

After expansion from a gas tube turbine, the hot exhaust gases are used to heat the compressed air from a compressor with the help of a cross flow compact heat exchanger of 0.8 effectiveness. What is the number of transfer units of the heat exchanger?

Question 8

Consider the following statements:
1) Mass transfer refers to mass in transit due to a species concentration gradient in a mixture.
2) Must have a mixture of two or more species for mass transfer to occur.
3) The species concentration gradient is the driving potential for mass transfer.
4) Mass transfer by diffusion is analogous to heat transfer by conduction.
Which of these statement are correct?

Question 9

For a fluid with Prandti number Pr>1, momentum boundary layer thickness

Question 10

Match List-I with List-II and select the correct answer using the code given below the Lists:
List-I
A) Stanton number
B) Grashoff number
C) Peclet number
D) Schmidt number
List-II
1) Natural convection
2) Mass transfer
3) Forced convection
4) Forced convection for small Pr. Number

Question 11

Thermal boundary layer is a region where:

Question 12

What is the critical radius of insulation for a sphere equal to_____?

Where k = Thermal conductivity of insulation
h = Convective heat transfer coefficient

Question 13

A wall of thickness 0.6 m has a normal area 1.5 m² and is made up of material of thermal conductivity 0.4 W/mK. The temperature on the two sides are 800⁰ C and 100⁰ C. What is the thermal resistance of the wall?

Question 14

A composite wall of a furnace has 2 layers of equal thickness have thermal conductivities in the ratio of 3 : 2. What is the ratio of the temperature drop across the two layers?

Question 15

In order to achieve maximum heat dissipation, the fin should be designed in such a way that :