ME or MEng Master of Engineering Thermodynamics and Heat Transfer 2

Question 1

The effectiveness-NTU method in heat exchanger analysis defines effectiveness as:

Accepted Answer

Ratio of actual heat transfer to maximum possible heat transfer

Answer

Ratio of outlet to inlet temperature

Answer

Number of transfer units divided by flow rate

Answer

Ratio of hot-side to cold-side heat capacity rates

Question 2

In the Rankine cycle used in steam power plants, which component increases the pressure of the working fluid?

Accepted Answer

Pump

Answer

Turbine

Answer

Condenser

Answer

Boiler

Question 3

Stefan-Boltzmann Law states that thermal radiation emitted by a blackbody is proportional to:

Accepted Answer

T⁴

Answer

T²

Answer

T³

Answer

T^0.5

Question 4

Superheat in a Rankine cycle is added primarily to:

Accepted Answer

Increase turbine efficiency and reduce moisture content

Answer

Reduce pump work

Answer

Increase condenser pressure

Answer

Lower boiler operating temperature

Question 5

The Biot number in heat transfer is defined as:

Accepted Answer

hL/k, ratio of convective to conductive resistance

Answer

k/(ρcL), thermal diffusivity parameter

Answer

ρVL/μ, inertial to viscous ratio

Answer

hL/α, convection-diffusivity ratio

Question 6

In a refrigeration cycle, the Coefficient of Performance (COP) is defined as:

Accepted Answer

Heat removed from the cold space divided by work input

Answer

Work input divided by heat removed from the cold space

Answer

Heat rejected to the hot reservoir divided by work input

Answer

Work output divided by heat absorbed