HYDROFLOW is a solution for ultrasonic flow speed metering in non-stationary conditions

MOTRHYS ultrasonic and pressure measurements on a penstock

MOTRHYS provides innovative data processing dedicated to non-intrusive ultrasonic flow measurement. Wherever the conditions for ultrasonic flow metering are not fulfilled, data processing with our software HYDROFLOW brings a solution. Ultrasonic monitoring of flow in challenging installations becomes possible: pipe system singularities, non-stationary flow with rapidly changing conditions… 

MOTRHYS proposes an innovative and unique service as a key part of the monitoring of all water installation.

Application fields:

HYDROFLOW software can be easily connected with existing acoustic flow metering systems to extend their range of performing as well as to increase their accuracy in in-stationary conditions. This software integration will contribute to reducing considerably the cost of flow metering processes. The innovative signal processing of MOTRHYS allows using clamp-on sensors to both calculate the average speed and the associated speed profile. The average speed is calculated by using  time of flight method. And the speed profile is defined by using Doppler effect from a multi-sensor configuration

HYDROFLOW broadens the scope of
clamp-on ultrasonic velocity profile determination:

Ultrasonic flow measurement in non-stationary conditions

By using HYDROFLOW software, powered by ABIUS technology  for  « Adaptive Beamforming for non-Instrusive Ultrasonic Sensors”, MOTRHYS provides the all level processing of acoustic signals of a multi-sensor configuration for the estimation of flow speed profile in the in stationary conditions – see next figure:

Multi-sensor configuration: by using many acoustic path, it is possible to get the 3D flow rate profile

Single sensor level: the wide band signal transmitted by the EM sensor will contain, at the receiver sensors, information of time of flight as well as Doppler deformation. The processing of the received signal will allow estimating these parameters

Multi-element sensor: as suggested by the previous figure, each sensor will have four elements. By digitally controlling the phase delay between these elements, ABIUS allows the electronically beam forming, helping to focus the acoustic path to the direction of maximum of the energy. In this way, it is possible to have a much wider range of flow rate

Multi-sensor configuration: by using many acoustic path, it is possible to get the 3D flow rate profile, independently of the spatial configuration.

HYDROFLOW software powered by ABIUS technology: testbench proofs-of-concept

Estimation of an asymmetric flow profile in turbulent conditions

Estimation of an asymmetric flow profile
Blue line – real vertical flow profile, measured with a Pitot tube;
Red line – Estimated vertical profile with clamp-on
ultrasonic sensors and ABIUS processing

Double function: flowrate metering and transient pressure measurement...

Thanks to ABIUS processing, clamp-on ultrasonic sensors allow two functions in one: flow rate metering and transient pressure measuring

With ABIUS technology, it becomes possible to use a standard acoustic flow metering system to measure the speed of the transient pressure wave created by an opening/close of a valve, for instance.

Recap of ultrasonic flow measurement techniques.

Flow rate measurements are crucial for the monitoring of any hydro equipment. Currently, different techniques exist: electromagnetic, laser/optical, X-ray, electromechanical, ultrasonic, … Among all these techniques, the ultrasonic flow measurement systems are the most suitable in practical application, since they can be non intrusive (by the use of clamp-on sensors) , easy to install and flexible.

The main technique of ultrasonic flow metering is the time-of-flight measurement, described by the following picture:

This technique allows the flow rate measurement only if the flow speed profile is completely known in the whole measurement section. It is generally true if the flow is stationary in both time and space. See condition stated by the IEC 60041 standard: Field acceptance tests to determine the hydraulic performance of hydraulic turbines, storage pumps and pump-turbines.

Ultrasonic velocity profile determination may be impossible...

In practice, several limitations restrict the use of this ultrasonic technique. In particular, the non-respect of these above standard’s constraints which can be interpreted as spatial and time non-stationary context. 

Performing in the spatial configuration out of the conditions defined in the standard  cause an inaccurate result.

So, the non stationary flow conditions, whether from water system configuration or water speed variation, is a blocking point. Making it impossible to determine the velocity profile  by means of ultrasonic measurement. For example:

The distance between elbow and measurement section is much lower than 20 diameters – out of standard conditions

The presence of diaphragm makes the flow rate profile asymmetrical

Water speed: Fast variation of flow rate (high dynamic fluids), the acoustic sensing can loss its property (flow blow effect, illustrated in the figure)