Methods, apparatus, and systems to monitor health of a closed loop in a turbine engine using a physics-based model

A non-transitory computer readable medium comprising instructions which, when executed, cause processor circuitry to at least:

• iteratively determine a volume of a chemical compound in a system of a turbine engine based on a pressure measurement using a thermodynamic state model, a temperature measurement, and a constant that corresponds to a thermodynamic state;
• determine a mass of the chemical compound based on the volume of the chemical compound and a volume of system;
• iteratively determine a mass loss of the chemical compound based on the mass of the chemical compound using a system of equations;
• and
• adjust use of the system of the chemical compound based on the mass loss of the chemical compound.

An apparatus comprising:

• a non-transitory memory storing computer readable instructions thereon;
• and
• processor circuitry to execute the computer readable instructions to:
• iteratively determine a volume of a chemical compound in a system of a turbine engine based on a pressure measurement using a thermodynamic state model, a temperature measurement, and a constant that corresponds to a thermodynamic state;
• determine a mass of the chemical compound based on the volume of the chemical compound and a volume of the system;
• iteratively determine a mass loss of the chemical compound based on the mass of the chemical compound using a system of equations;
• and
• adjust use of the system of the chemical compound based on the mass loss of the chemical compound.