Thermodynamics and Heat Transfer Flashcards
6 cards from real ME or MEng Master of Engineering practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Thermodynamics and Heat Transfer flashcards as text
Which heat transfer mode does NOT require a medium (can occur in a vacuum)?
Answer: Radiation
Thermal radiation is electromagnetic energy transfer that requires no medium, allowing heat transfer across a vacuum.
In a gas turbine (Brayton) cycle, the ideal thermal efficiency depends on:
Answer: Pressure ratio
Brayton cycle efficiency η = 1 − r_p^((1−γ)/γ), depending only on the pressure ratio r_p and the specific heat ratio γ.
The first law of thermodynamics applied to an open steady-flow system is expressed as:
Answer: Q − W_s = Δh + ΔKE + ΔPE
For steady-flow open systems, the energy balance per unit mass is Q − W_s = Δh + ΔKE + ΔPE (shaft work, enthalpy, kinetic and potential energy changes).
A fin on a heat sink increases heat dissipation primarily by:
Answer: Increasing the surface area for convection
Fins extend surface area available for convective heat transfer, increasing the rate of heat dissipation from the base surface.
Exergy (availability) in thermodynamics represents:
Answer: Maximum useful work obtainable relative to the environment
Exergy is the maximum theoretical work that can be extracted as a system comes to equilibrium with its surroundings.
The temperature at which a gas condenses at a given pressure is called its:
Answer: Dew point
The dew point is the temperature at which a gas (or gas mixture) begins to condense at a specified pressure.