Tele-Metrology and Advanced Ultrasonic Flow Metering (Updated Version)
Pedro I. Espina, Tsyh Tyan Yeh, P I. Rothfleisch, S A. Osella
In an effort to expand the range of the national standards, NIST is experimenting with tele-metrology concepts to annex flow calibration facilities throughout the U.S. An essential part of this approach is the use of sensors capable of assessing the dynamic properties of the flow-testing environment. Specifically, we advocate the use of an advanced ultrasonic flow meter (AUFM) to provide the detailed description of the flow field enterning the flow meter being calibrated. The AUFM couples multi-path ultrasonic sensing capabilities with pattern recognition software to provide likely flow fields and their probability of existance. The knowledge encoded in the pattern recognition software is derived from training exercises that use cmputational fuluid dynamic and experimental results to teach a flow field recognizer (FFR) via learning algorithms. The performance of the FFR is proportional to the number of and variety of example flow fields used during training, and the flow detection features used for classification. Although the purpose of this research is to reduce the uncertainty of flow calibration devices, the use of the AUFM could prove beneficial in field applications where installation effects can lead to gross errors when ultrasonic signals are evaluated using conventional integration schemes.