ME or MEng Master of Engineering Thermodynamics and Heat Transfer

Question 1

Which thermodynamic cycle is the theoretical standard for spark-ignition gasoline engines?

Accepted Answer

Otto cycle

Answer

The Otto cycle models the idealized operation of a spark-ignition internal combustion engine with constant-volume heat addition.

Question 2

What does the Clausius inequality state about a thermodynamic cycle?

Accepted Answer

The cyclic integral of dQ/T is less than or equal to zero

Answer

The Clausius inequality states that the cyclic integral of δQ/T ≤ 0, with equality for reversible processes, forming the basis of the second law.

Question 3

In a heat exchanger, the LMTD method stands for:

Accepted Answer

Logarithmic Mean Temperature Difference

Answer

LMTD (Logarithmic Mean Temperature Difference) is used to determine the driving force for heat transfer in a heat exchanger.

Question 4

The thermal efficiency of a Carnot heat engine operating between 600 K (hot) and 300 K (cold) is:

Accepted Answer

50%

Answer

Carnot efficiency = 1 − T_cold/T_hot = 1 − 300/600 = 0.50 or 50%.

Question 5

Fourier's Law of heat conduction relates heat flux to:

Accepted Answer

The negative of the temperature gradient

Answer

Fourier's Law states q = −k∇T, meaning heat flux is proportional to the negative temperature gradient.

ME or MEng Master of Engineering Practice Test