BME Thermodynamics 4

Question 1

The Diesel cycle differs from the Otto cycle in that heat addition occurs at constant:

Accepted Answer

Pressure

Answer

In the Diesel cycle, fuel injection and combustion occur at constant pressure, unlike the Otto cycle where heat is added at constant volume.

Question 2

The Gibbs phase rule (F = C - P + 2) for a single-component system at a point on the saturation curve gives how many degrees of freedom?

Accepted Answer

1

Answer

For a single component (C=1) with two phases (P=2): F = 1 - 2 + 2 = 1, meaning only one intensive variable can be specified independently.

Question 3

For an ideal gas mixture, Dalton's Law states that the total pressure equals:

Accepted Answer

The sum of the partial pressures of all components

Answer

Dalton's Law states that the total pressure of an ideal gas mixture equals the sum of the partial pressures each gas would exert alone.

Question 4

The effectiveness of a heat exchanger is defined as the ratio of:

Accepted Answer

Actual heat transfer to maximum possible heat transfer

Answer

Effectiveness ε = Q_actual / Q_max, where Q_max is the maximum heat transfer achievable with an infinitely long counterflow exchanger.

Question 5

The Helmholtz free energy A is defined as:

Accepted Answer

A = U - TS

Answer

Helmholtz free energy A = U - TS, and it represents the maximum work obtainable from a closed system at constant temperature and volume.

BME - Bachelor of Mechanical Engineering Practice Test