Comparison of four conductive needle probe designs for determination of bubble velocity and local gas holdup

Munholand, Luke; Soucy, Gervais
September 2005
Review of Scientific Instruments;Sep2005, Vol. 76 Issue 9, p095101
Academic Journal
Four conductive needle probe designs were compared in order to determine which probe was most effective at measuring local gas fraction holdup and bubble velocity. Test conditions were identical for all probes with global gas fraction holdup [variant_greek_epsilon]g=0.018±0.002 Lgas/Ltotal and mean bubble velocities at 0.296±0.141 m/s. Video was used to validate the probe measurements. Fluid mechanics theory suggests the smallest probe should give the most accurate results. However, in tests the smallest probe performed poorly due to a low signal-to-noise ratio (SNR). The largest probe gave the best results due to its excellent SNR and appropriately spaced sensors.


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