Aerospace Flow Measurement Solutions - Turbine Engine Test & Overhaul Stands

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In the aerospace industry, ground testing of fuel systems and components is critical to insure flight worthiness. Engineers for these systems and components require valid data to insure that they completely understand the operation of the system or individual component under many environmental conditions.

Turbine flowmeters are the choice when accuracy, range, dynamic response and changing environmental conditions are encountered.

Jet turbine engine manufacturers use the FT Series flowmeter and Linear Link flow meter linearizer to measure fuel flow over a wide range (ex: 0.6 to 60 GPM) flow range. Data is typically required with the fuel at various temperatures and accuracy is critical.

Turbine flow meters are one of the most accurate flow sensors available today if used and calibrated properly. Remember that your flow meter is only as good as it’s calibration. Turbine flow meter accuracy is affected by the kinematic viscosity of the fluid being measured. For this reason, a calibration in fluid of the same kinematic viscosity is required to achieve the best accuracy. Because fluid kinematic viscosity changes due to temperature, multiple calibrations at different kinematic viscosities would be required.

Linear Link TCI for viscosity compensation


The Flow Technology Linear Link TCI product performs viscosity compensation techniques. Turbine flow meters can use a technique referred to as a “Universal Viscosity Curve” to operate over varying kinematic viscosity values. This process involves calibrating the flow meter over the viscosity range and using electronics to determine the correct flow rate based on the input temperature of the fluid and the frequency from the flow meter. Limitations of this technique include calibrating the flow meter at kinematic viscosity’s that do not vary by more than a 10:1 ratio from one another over the range of kinematic viscosity’s and limiting the range of the meter to a 10:1 turndown. Operation at extended ranges is possible; however accuracy of the output will degrade due to a drop off in flow meter linearity when operated outside of the 10:1 normal flow range.

Flow Technology's Linear Link linearizer for turbine flow meters


When data accuracy is critical over a wide temperature and flow range, the Linear Link is utilized. For instance, to address the wide temperature range, a customer determined that 5 discreet fluid temperatures were required for their data requirements. The solution for this requirement is to calibrate the flow meter in fluids that match the kinematic viscosity’s of the fluid at the 5 different temperatures. To address the wide flow range required (100:1 turndown), linearization would be required to be performed by the flow meter’s electronics. The Flow Technology Linear Link provides this capability and will insure the linearity of the flow meter will meet a ± 0.1% reading specification over the 100:1 turndown.

A logo of Visual Link

The Linear Link flow meter linearizer is provided with VisualLinK software that allows the customer to program the Linear Link with calibration data. For this application, data would be acquired with the fluid at a given temperature corresponding to one of the calibrations performed on the flowmeter. The fluid temperature would then be changed to the next value and additional data acquired. This requires that the calibration data for the next kinematic viscosity be loaded into the Linear Link electronics for the best possible accuracy. This is easily accomplished using the VisualLinK software and programming cable for the Linear Link.

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