Working substance

Definition

A working substance is the material or fluid within a heat engine that undergoes a thermodynamic cycle, absorbing and rejecting heat to produce work. It is essential for the conversion of thermal energy into mechanical energy.

5 Must Know Facts For Your Next Test

1. The working substance in an ideal gas cycle follows the laws of thermodynamics closely, making it a common model for heat engines.
2. In a Carnot engine, the working substance undergoes two isothermal processes and two adiabatic processes.
3. The efficiency of a heat engine depends on the properties and behavior of its working substance.
4. Real-world examples of working substances include steam in steam engines and refrigerants in refrigerators.
5. The performance of the working substance can be described using state variables like pressure, volume, temperature, and entropy.

Review Questions

• What role does the working substance play in a heat engine?
• How do the properties of a working substance affect the efficiency of a Carnot engine?
• Name at least two real-world examples of working substances.

Related terms

Heat Engine: A device that converts thermal energy into mechanical work by undergoing a cyclic process involving heat transfer.

Carnot Cycle: An idealized thermodynamic cycle proposed by Sadi Carnot that provides maximum possible efficiency for a heat engine operating between two temperatures.

Adiabatic Process:

A process in which no heat is transferred to or from the system, meaning all changes in internal energy are due to work done by or on the system.