Thermodynamics & Heat Transfer
Laws of thermodynamics, phase equilibria, gas power cycles, psychrometrics, and entropy/exergy analysis.
Theory Modules
Study the theory, review the governing formula, and test your knowledge with interactive questions.
Basic Concepts and Definitions
Thermodynamics studies energy, heat, work, and the properties of matter and their changes. A system is a specified po...
Brayton Cycle
The Brayton cycle models the ideal continuous-flow processes of a gas-turbine engine. It consists of four processes:...
Carnot Cycle
The Carnot cycle is an idealized reversible heat engine cycle operating between two fixed temperature reservoirs: a h...
Closed Systems
Closed systems (control mass) are thermodynamic systems in which a fixed amount of mass is considered; no mass crosse...
Combustion
Combustion is a rapid exothermic chemical reaction between a fuel and an oxidizer that converts chemical energy into...
Compressors
Compressors are turbomachines or positive-displacement devices that increase the pressure of a working fluid (usually...
Diesel Cycle
The ideal Diesel cycle is a four-step thermodynamic model for compression-ignition (diesel) engines. The idealized st...
Dual Cycle
The dual (mixed) cycle is an air‑standard internal combustion cycle that models heat addition as a combination of a c...
Enthalpy
Enthalpy (H) is a thermodynamic state function defined as H = U + pV for a system, where U is internal energy, p pres...
Entropy
Entropy is a state function that quantifies the dispersal of energy and the number of accessible microstates for a sy...
Exergy
Exergy (also called availability) is the maximum useful work obtainable from a system as it is brought reversibly to...
The First Law of Thermodynamics
The First Law of Thermodynamics is a statement of energy conservation for thermodynamic systems: energy can be transf...
Gas Mixtures
Gas mixtures (ideal) are composed of two or more gaseous species that share the same volume, temperature and (for a m...
Gas Turbines
Gas turbines operate on the Brayton (or Joule) cycle: air is compressed, fuel is added and combusted at (approximatel...
Heat Pumps
A heat pump is a device that transfers thermal energy from a lower-temperature reservoir (source) to a higher-tempera...
Humid Air / Psychrometry
Psychrometry (humid air) studies the thermodynamic and transport properties of air–water vapor mixtures. Important st...
Ideal Gases
Ideal gas theory models a dilute gas in which (1) molecules are point particles with negligible volume, (2) intermole...
Nozzles and Diffusers
Nozzles and diffusers are steady-flow aerodynamic devices that convert between pressure (enthalpy) and kinetic energy...
Open Systems
Open systems (control volumes) are thermodynamic systems through which mass and energy can cross the system boundarie...
Otto Cycle
The Otto cycle is the idealized thermodynamic cycle for spark-ignition (SI) internal-combustion engines. In the air-s...
Pure Substances and Phase Transitions
Pure substances have distinct phases (solid, liquid, vapor) with phase boundaries in pressure–temperature (p–T) space...
Rankine Cycle
The Rankine cycle is the basic thermodynamic cycle for steam power plants. It consists of four idealized processes: i...
Real Gases
Real gases deviate from ideal-gas behaviour because of finite molecular size and intermolecular forces. Deviations ar...
Refrigeration Cycles
Refrigeration cycles transfer heat from a low-temperature reservoir to a higher-temperature reservoir by input of wor...
The Second Law of Thermodynamics
The Second Law of Thermodynamics establishes the direction of spontaneous processes and introduces entropy as a state...
Steam Turbines
Steam turbines convert thermal energy of steam into mechanical work by expansion through nozzles and blades. They are...
Systems and Control Volumes
A system (control mass) is a fixed amount of matter tracked through time; no mass crosses its boundary, but energy ca...
Systems with Continuous Flow
Systems with Continuous Flow (control-volume, steady or unsteady) describe mass and energy exchange across control su...
Vapor and Vapor Tables
Vapor and vapor tables concern the thermodynamic properties of a pure substance in the two-phase region (liquid + vap...
The Zeroth Law of Thermodynamics
The Zeroth Law of Thermodynamics states that if two thermodynamic systems A and B are each in thermal equilibrium wit...