Patent ID: 7139667

Claim:
A method of determining an average flow rate of a fluid flowing in the pipe, said method comprising: measuring unsteady pressures using an array of sensors, wherein each sensor is spaced at different axial locations along the pipe; determining, in response to the measured unsteady pressures, a measured flow rate of the fluid flow; relating the measured flow rate to the average flow rate of the fluid using a calibration correction function based on non-dimensional parameters that characterize the array of sensors, the pipe, and the fluid flowing in the pipe to determine a flow signal indicative of the average flow rate, and providing the average flow rate to an output device for retrieval by a user, wherein the calibration correction function depends on at least two of a ratio t/D of the pipe wall thickness (t) and the pipe inner diameter (D); a Reynolds number that characterizes the fluid flow in the pipe; a ratio Δx/D of the sensor spacing (Δx) and the pipe inner diameter (D); and a ratio fΔx/U meas of usable frequencies in relation to the sensor spacing (Δx) and the measured flow rate (U meas ).