Medição de vazão em dutos parcialmente preenchidos por espalhamento da radiação gama e a técnica de medida da função de “Cross Correlation”

Abstract

Measurement of water consumption by different users (industrial, agricultural, urban) is essential, because in many countries the ”royalties” of water per consumer are differentiated by the customer profile. Therefore, the objective of this work was to develop a method for water flow meters calibration with uncertainty less than 1.0 % applying radiotracer and Cross Correlation techniques. The experimental tests were carried out in a 30 m length water transport line, constructed in Polyvinyl chloride. Br-82 was used as radiotracer and injected as a fast pulse with volumes between 2.0 and 3.0 ml depending on the water flow rate investigated. The data recording were made with sampling rates ranging from 20 Hz to 1 kHz. A correlator (hardware and software) was developed using special mathematical methods, such as Savitzky-Golay filtering and Lagrange interpolation in order to reduce the uncertainty of flow measurement. This methodology used along with calculations of water volumes fractions by mean of mathematical simulations with code MCNPX and static experimental measurements made possible to measure flow rate in partially filled tubes.