Notations and main common quantities
Aerospace propulsion - An introduction

The units most often used in this article are those of the International System (SI). A speed is expressed in meters per second (m.s^-1), a pressure in pascal (Pa), or even in bar (1 bar = 105 Pa) or MPa. Thermodynamic quantities for fluids used in propulsion, involving the joule (J) or watt (W), such as thermal mass capacities (c_p, c_V, and by extension r), are expressed in J.kg^-1.K^-1. Temperatures are expressed in kelvin (K).

The main Anglo-Saxon units still used in propulsion articles and books are listed below:

• for pressure, 1 psi (pound per square inch) corresponds to 6,897 Pa (this is why some propellant reference pressures are given for 70 bar. Similarly,...