Contrec - 515-SC02 – Steam Flow Computer

Analogue Input Steam Computer

The 515-SC02 steam computer measures the volume, mass and energy content of steam by using analog volume flow in conjunction with a temperature and/or pressure input.

A selection of various modes makes it suitable for many steam applications. The Flowmeter input signal can be selected as either 0-5V, 1-5V or 4-20mA. Minimum and maximum points are programmed and non-linear correction points can be used to better reflect the flowmeters behaviour.

The steam computer calculates the mass flow and energy according to the IAPWS Industrial Formulation (1997) for the thermodynamic properties of steam. The equations use pressure and temperature values to determine the specific volume and the specific enthalpy.

Calculations

The steam energy calculations are based on the IAPWS Industrial Formulation (1997).

Superheated steam regions are:
• 0°C < t < 800°C P < 100MPa
• 32°F < t < 1472°F P < 14500psia
• 800°C < t < 2000°C P < 10MPa
• 1472°F < t < 3632°F P < 1450psia

Saturated steam regions are:
• 0°C < t < 374°C (critical temperature)
• 32°F < t < 705°F
• P < 22MPa (critical pressure)
• P < 3190psia

Water region is:
• 0°C < t < t saturation at system pressure
• 32°C < t < t saturation at system pressure

Formulas:
• Mass flow = Volume flow/Specific volume
• Energy flow = Mass flow x Specific enthalpy