Introduction to Engineering Thermodynamics

Vocabulary flashcards covering the fundamental concepts, terminology, system properties, laws, and cycles of basic engineering thermodynamics.

Engineering Thermodynamics

The study of energy, heat, and work, including how energy converts and transfers across systems, and how thermodynamic laws are applied to engineering systems such as engines, power plants, steam and gas turbines, refrigerators, and air conditioners.

System

The specific part of the universe that is chosen for thermodynamic study (for example, a gas contained within a piston or liquid inside a bottle).

Surroundings

Everything in the universe that exists outside the defined thermodynamic system.

Boundary

The surface or interface, real or imaginary, that separates a thermodynamic system from its surroundings.

Extensive Property

A thermodynamic property of a system that depends directly on the size or extent of the system, such as mass or volume.

Intensive Property

A thermodynamic property of a system that is independent of the size or extent of the system, such as temperature or pressure.

Thermodynamic Process

A change in a thermodynamic system from one equilibrium state to another (such as the heating of water).

Thermodynamic Cycle

A continuous series of thermodynamic processes that eventually return the working fluid or system to its initial state (such as the cycles in engines or refrigeration plants).

First Law of Thermodynamics

The principle of energy conservation, stating that energy can neither be created nor destroyed; it can only be converted between different forms.

Second Law of Thermodynamics

A law stating that the entropy of a closed system always increases over time, meaning that processes are irreversible without an input of energy, heat spontaneously moves only from hotter bodies to colder bodies, and no heat engine can achieve $100\%$ efficiency.

Entropy

A measure of disorder within a closed system that spontaneously increases over time according to the Second Law of Thermodynamics.

Heat Engine

A cyclically operating thermodynamic device that absorbs heat ($|Q_H|$) from a high-temperature source ($T_H$), delivers net work output ($|W|$), and discharges waste heat ($|Q_L|$) to a low-temperature sink ($T_L$).

Convection

A heat transfer process demonstrated in boiling fluids where hotter, less dense fluid rises while cooler, denser fluid sinks, forming a circulation loop.

Boiler Energy Losses

The energy dissipated during steam generation from inlet fuel, which leaves the system through flue gas, blowdown, dust and unburnt fuel, and convection and radiation.

Phase Transitions

Physical transformations between states of matter (solid, liquid, and gas), including melting (solid to liquid), freezing (liquid to solid), vaporization (liquid to gas), and condensation (gas to liquid).

Refrigeration Cycle

A closed loop that circulates refrigerant through a compressor, condenser, expansion valve, and evaporator to absorb heat at low temperature and reject it at higher temperature.