The propellant mass fraction density, often denoted as , is a measure of the mass of propellant per unit volume. In the context of propulsion systems, especially in aerospace engineering, it refers to the density of the propellant used in rocket engines, thrusters, or other propulsion devices.
Where:
- is the propellant mass fraction density.
- is the mass of propellant.
- is the volume occupied by the propellant.