The oxidizer-to-fuel ratio for solid propellant rockets refers to the ratio of the mass of the oxidizer to the mass of the fuel in the solid propellant composition. This ratio is a critical parameter for designing and controlling the performance of solid rocket motors. In solid rocket propellants, both the fuel and oxidizer are intimately mixed together in a solid form, and the O/F ratio is defined by the mass of the ingredients used.
The mole-based O/F ratio (ξ) is calculated by dividing the moles of the oxidizer (n_ox) by the moles of the fuel (n_fuel). The molar masses of the oxidizer and fuel should be in grams per mole (g/mol) to ensure consistency. The formula is as follows:
The units of ξ are typically mol/mol.