Air Density from Enthalpy and Temperature
What is Air Density from Enthalpy and Temperature?
Air density is the mass of air per unit volume and is influenced by factors like temperature, pressure, and moisture content. When the enthalpy (total heat content) and temperature of air are known, air density can be estimated using thermodynamic relationships.
How to Calculate:
To calculate air density from enthalpy and temperature, you can use a rearranged form of the ideal gas law, adjusted with specific heat:
Formula:
ρ = P / [R × T × (1 + ((h / cp) – T) / T)]
- ρ = Air density (kg/m³)
- P = Atmospheric pressure (assumed 101.325 kPa)
- R = Specific gas constant for dry air ≈ 0.287 kJ/kg·K
- T = Temperature in Kelvin
- h = Enthalpy in kJ/kg
- cp = Specific heat capacity ≈ 1.005 kJ/kg·K