Function Call “=H2o.PTU(pressure, temperature, units, metastable)”

Input Parameters

• Pressure: (0)MPa, (1)psia, (2)bara, (3)kPa
• Temperature: (0)K, (1)°F, (2)°C, (3)°C
• Units: (0)SI, (1)US Customary, (2)Metric bara, (3) Metric kPa
• Metastable: false=normal, true=metastable

Return Value

• Internal Energy: (0)kJ/kg, (1)BTU/lbm, (2)kJ/kg, (3)kJ/kg

Default values: Units: (0)SI; Metastable: false

Metastable conditions may occur during a sudden steam expansion that crosses over from superheated to saturated conditions. The metastable calculations are valid from the saturated-vapor line to the 5% equilibrium moisture line for pressures from the triple-point pressure up to 10 MPa.

Reference Document: IAPWS R7-97

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