TM

Ultrasonic Air Mass Flow Rate Measurement for Industrial Gas Turbines (Siemens, Alstom, GE, Mitsubishi) Specifications

Air Speed Range 0 to 200 ft/s (0 to 60 m/s)

Sound Path Length 1 - 20 ft (30 cm to 6 m)

Air Temperature Range -22 to 176 °F (-30 to 70 °C)

Air Pressure Range 12 to 16 psia (800 to 1100 mbar)

Relative Humidity Range 0 to 100% Evaporative cooling – yes Inlet chilling below dew point - yes Inlet fogging - yes

Update Interval < 0.5 s for typical gas turbine inlet

duct dimensions

Accuracy of Calculated Values Air speed systematic uncertainty (2σ)

typically less than 0.5% of reading at nominal maximum air speed

Air mass flow rate systematic uncertainty (2σ) typically less than 1.0% of reading at nominal maximum mass flow rate

Accuracy of Base Measurements Probe tip coordinates and duct dimensions

determined from 3D laser survey with 0.04” (1 mm) accuracy

Sound pulse flight times measured using oven controlled crystal oscillator (OCXO) to 0.5 µs accuracy

Static air pressure measured to 0.1% accuracy (0.05% optional)

Principle of Measurement Air mass flow rate = air mass flux

x duct area x duct factor Air mass flux = air speed x air density Air speed: calculated from sound pulse

flight times and probe tip coordinates Air density: calculated from sonic velocity

and static air pressure Sonic velocity: calculated from sound pulse

flight times and probe tip coordinates Duct area: determined from duct survey Duct factor: determined from CFD analysis

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Data CommunicationsAll AirSonic data is accessible via OPC or MODBUS TCP. The signals include:

Air density (lb/ft3) Air flow angle (°) Air mass flux (lb/s/ft2) Air mass flow rate (lb/s) Air pressure (psia) Air speed (ft/s) Air velocities (ft/s) Air volumetric flow rate (ft3/s) Flight times (ms) Sonic Velocity (ft/s)

Ultrasonic Probes

Material: Probe Housing: Aluminum Transducers: Aluminum

Weight: 5 lbs each

Size: 4 ¾” maximum diameter, 7 ¾” long

Protrusion (Interior of Inlet Duct): 4” maximum

Protrusion (Exterior of Inlet Duct): 3” maximum

Environmental Specification NEMA4 (IP65) -22 °F to 176 °F (-30 °C to 70 °C) Maximum duct pressure drop: 20 inH2O

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Control Box

DimensionsMain Enclosure Weight: 82 lbSize (H x W x D): 24” x 24” x 8”

Enclosure 14 ga steel, solid single door, flush-mount Finish: ANSI 61 gray UL 508A Listed; Type 4, 12; File No. E61997 NEMA/EEMAC Type 4, 12, 13 CSA, File No. 42186: Type 4, 12 VDE IP66 IEC 60529, IP66

Power Supplies 110 – 120 VAC, 60 Hz Standard 220 – 240 VAC, 50 Hz Optional

Power Consumption< 10 amps

Operating Temperature-22 °F to 122 °F (-30 °C to 50 °C)

Storage Temperature-67 °F to 167 °F (-55 °C to 75 °C)

Transducer Cables

4 pair, individual & overall shieldedConnectors: NEMA4 (IP65)

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Example Locations For Gas Turbine Ducts

Rectangular

Siemens 501G

Mitsubishi 501G Inlet Duct Probe Locations

GE 7FA

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