Method and apparatus for flow rate measurement

Abstract

The average volumetric velocity U.sub.m of a fluid flowing within a large industrial flue stack is determined by a combination of measurement and calculation techniques. The temperature, velocity head and static pressure of the stack fluid are measured at two points within the bounded path of the flue stack. The flight time of a random acoustic noise wave is measured in both the upstream and downstream directions. The path average velocity U.sub.p is determined from the measured values of the upstream and downstream flight times. The fluid velocity is determined using the measured values of the flight times, the fluid temperature, velocity head and static fluid pressure. The determined values of the path average velocity U.sub.p and the fluid velocities are used to determine the average volumetric velocity U.sub.m. A curve fitting algorithm is employed to determine an approximation of the actual fluid flow distribution across the bounded path, and this approximation is used to calculate U.sub.m. The average moisture content contained in the flue stack volume is also determined by adding additional sensors to measure the values for oxygen and carbon dioxide, and using these measured values along with the measured values of the flight times and temperature.

Dependencies are inferred from the claim text.