Experimental Research of Vortex Street Oil-Gas-Water Three-Phase Flow Base on Wavelet

Vortex flowmeter was chosen to measuring the oil-gas-water three-phases flow due to its various of characteristics, experiment has been reported in the conditions as follows: vertical upward pipeline with 50 mm diameter, the volumetric flow of water is 5-8 m(3) h(-1), oil account for 5-30 % of the total mixed flow and the gas proportion of the gas void fraction is from 1 to 5 %. The signals collected by vortex sensor are compressed and de-noised by ddencmp function. As PSD (power spectral density) peak values and variations in water flow have a very clear relationship, based on the feature of wavelet transformation, criteria may be found to distinguish different flow. The result shows that low-frequency energy is greatly influenced by the oil content and low-frequency energy is declined with the oil content is increased while low-frequency energy is increased with the gas void fraction is increased. There is a flow threshold, when the three-phase flow does not reach the threshold, the influence on Low-frequency energy by the gas void fraction can be ignored. The volume measured by the vortex flow-meter was less influenced by media with low gas void fraction.