Flow velocity profiling using acoustic time of flight flow metering based on wide band signals and adaptive beam-forming techniques

Irina Murgan (1) , Ion Candel (1) , Cornel Ioana (1) , Angela Digulescu (1) , Florentina Bunea (2) , G Ciocan (3) , Andrei Anghel (4, 1) , Gabriel Vasile (1)

1 GIPSA-SIGMAPHY - GIPSA - Signal Images Physique
2 National Institute for R&D for Electric Engineering ICPE-CA, Bucharest, Romania
3 ULaval - Université Laval [Québec]
4 UPB - University Politehnica of Bucharest [Romania]

In this paper, we present a novel approach to non-intrusive flow velocity profilingtechnique using multi-element sensor array and wide-band signal’s processing methods. Conventional techniques for the measurements of the flow velocity profiles are usually basedon intrusive instruments (current meters, acoustic Doppler profilers, Pitot tubes, etc.) that takepunctual velocity readings. Although very efficient, these choices are limited in terms ofpractical cases of applications especially when non-intrusive measurements techniques arerequired and/or a spatial accuracy of the velocity profiling is required This is due to factorsrelated to hydraulic machinery down time, the often long time duration needed to explore theentire section area, the frequent cumbersome number of devices that needs to be handledsimultaneously, or the impossibility to perform intrusive tests. In the case of non-intrusive flowprofiling methods based on acoustic techniques, previous methods concentrated on using alarge number of acoustic transducers placed around the measured section. Although feasible,this approach presents several major drawbacks such as a complicated signal timing,transmission, acquisition and recording system, resulting in a relative high cost of operation. Inaddition, because of the geometrical constraints, a desired number of sensors may not beinstalled. Recent results in acoustic flow metering based on wide band signals and adaptivebeamforming proved that it is possible to achieve flow velocity profiles using less acoustictransducers. In a normal acoustic time of flight path the transducers are both emitters andreceivers, sequentially changing their roles. In the new configuration, proposed in this paper, two new receivers are added on each side. Since the beam angles of each acoustic transducerare wide enough the newly added transducers can receive the transmitted signals and additionaltime of flight estimation can be done. Thus, several flow velocities are possible to becomputed. Analytically defined emitted wide band signals makes possible the identification ofsignals coming from each transducer. Using the adaptive beam-forming algorithm thereceiving transducers can record different signals from the receiver, equivalent to differentpropagation paths. Therefore, different measurements of time of flight are possible, leading toadditional flow velocity measurements. Results carried out in an experiment facility belongingto ICPE-CA, Bucharest - Romania allowed to the validation of the flow velocities computedusing this new technique, in symmetric, asymmetric and uneven flow conditions. The acousticderived values were referenced with those provided from a Pitot tube probe installed in the testchannel and the results obtained by the method proposed in this paper are relatively close tothis reference.

Domaines: Sciences de l'ingénieur [physics]

Irina Murgan, Ion Candel, Cornel Ioana, Angela Digulescu, Florentina Bunea, et al.. Flow velocity profiling using acoustic time of flight flow metering based on wide band signals and adaptive beam-forming techniques. IAHR 2016 - 28th IAHR symposium on Hydraulic Machinery and Systems, Jul 2016, Grenoble, France. ⟨10.1088/1755-1315/49/6/062003⟩. ⟨hal-01441803⟩