In aircraft design and engineering, “initial enthalpy” refers to the enthalpy of a fluid (such as air) before a specific process or change, such as compression, heating, or expansion. Enthalpy is a thermodynamic property that combines the internal energy of the fluid with the product of its pressure and volume.
The formula for calculating the initial enthalpy (H_initial) can be defined as:
- H_initial is the initial enthalpy, typically measured in joules per kilogram (J/kg) or other energy per unit mass units.
- Internal Energy represents the internal energy of the fluid before the process, typically measured in joules per kilogram (J/kg).
- Pressure is the pressure of the fluid before the process, typically measured in pascals (Pa) or any appropriate pressure unit.
- Specific Volume is the volume per unit mass of the fluid before the process, typically measured in cubic meters per kilogram (m³/kg) or other volume per unit mass units.