In aircraft design, when referring to the “density” of a spark ignition engine, it usually pertains to the air-fuel mixture’s density or the density of the working fluid within the engine. The formula for this density (ρ) is typically determined using the ideal gas law.
The ideal gas law relates the density (ρ), pressure (P), and temperature (T) of a gas and is expressed as:
– ρ (rho) = Density of the gas (in kilograms per cubic meter, kg/m³)
– P = Pressure of the gas (in pascals, Pa)
– R = Specific Gas Constant for the gas (in joules per kilogram-kelvin, J/(kg·K))
– T = Temperature of the gas (in kelvin, K)