The SONARtrac volumetric flow measurement system is a clamp on, non-contact, robust form of a flow-meter that utilizes sonar-based processing algorithms and an array of passive sensors to measure the flow of magnetite slurries.
According to the company, the sequence of events to perform the flow measurement is as follows:
• The movement of the turbulent eddies as the fluid flows creates a small pressure change on the inside of the pipe wall.
• This small pressure changes results in a dynamic strain of the pipe wall itself
• The mechanical dynamic strain signal is converted to an electrical signal through a passive sensor wrapped partially or fully around the pipe.
• This electrical signal is interpreted as a characteristic signature of the frequency and phase components of the turbulent eddies under the sensor.
• This characteristic signature is detected by each element of the array of sensors. These sensors are spaced a precisely set distance from each other along the axial direction of the pipe.
• An array processing algorithm combines the phase and frequency information of the sensor array elements to calculate the velocity of the characteristic signature as it convects under the array of sensors.
The strength of the array processing algorithm is the ability to distinguish and isolate signals from convecting turbulent eddies with those of acoustic waves and vibration.