Correlation Flow Measurement Principle

Correlation Flow Measurement Principle

Fast flowing fluids like steam are characterized by a turbulent flow profile.

Two ultrasonic transducer pairs are mounted with a defined distance onto the pipe forming two channels. They are sending ultrasonic signals through the pipe. This measurement method exploits the fact that ultrasonic signals are modulated by the turbulence pattern of the media, which the signals are sent through. The modulation of both signal channels are continuously compared to each other. Turbulence patterns, which passed both signal channels are recognized, and the traveling time is measured. Considering the distance between both channels and the traveling time of turbulence patterns between them, the flow velocity is determined.

Since ultrasounds propagate in solids, the transducers can be mounted onto the pipe. The measurement is therefore non-invasive, and thus no cutting or welding of pipes is required for the installation of the transducers.

[CFM Video]