Aerospace Flow Measurement Solutions - Turbine Engine Test & Overhaul Stands
ADVANCED SIGNAL PROCESSING
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.
WIDE TURNDOWN RANGE
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.
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.