Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
EXPERIMENTAL STUDY OF THE TRANSIENT GAS-LIQUID FLOW THROUGH AN ORIFICE PLATE USING HIGH SPEED CAMERA AND DIFFERENTIAL PRESSURE MEASUREMENT
Submission Author:
Emilio Paladino , SC
Co-Authors:
Josiane Weise, Rafael Franklin Lazaro de Cerqueira, Emilio Paladino
Presenter: Emilio Paladino
doi://10.26678/ABCM.COBEM2023.COB2023-0654
Abstract
Differential-pressure flow meters are widely used as a part of the systems designed for multiphase flow rate measurement without prior phase separation due to their characteristics of simplicity and robustness. For multiphase flows with high gas volume fraction (wet gas flow), a common approach is to measure the gas flow rate from the multiphase DP through the throttle device combined with an over-reading (OR) correlation. The liquid phase fraction is an input parameter in the OR correlations and the throttle device should be associated with some technique dedicated to phase fraction evaluation to allow inline multiphase flow rate measurement. A method proposed in the literature is the determination of the phase fraction from its correlation with statistical parameters of the transient DP signal fluctuations. In this way, gas and liquid mass flow rates can be measured by only one throttle device, considering the transient structure of the DP signal. The main purpose of this work is to investigate the relationship between the flow structure and transient DP signal of gas-liquid flows with high gas volume fraction and high gas superficial velocity to provide adequate physical support for the correlation between the fluctuations of the DP signal and the liquid phase fraction. The experimental investigation was developed by analyzing images captured from a High-Speed Camera (HSC) and measuring the DP signal in high gas content gas-liquid flow through an orifice plate. The experimental apparatus comprises a horizontal acrylic section with an internal diameter (D) of 25.4mm. The orifice plate with a diameter ratio of 0.5 was installed at 100D from the inlet. A set of superficial velocities of gas and liquid was evaluated, all within the region of stratified and wavy flow patterns. The HSC and the DP sensor were synchronized, allowing for the correlation between the observed flow structure and the DP signal. Liquid film height in the images was also determined from image processing techniques. The DP fluctuations depend mainly on the characteristics of the waves in the upstream flow of the orifice plate. The propagation of the waves through the orifice plate causes a significant decrease in the gas flow area, promoting large amplitude fluctuations in the DP signal. As the characteristics of the waves are fundamentally dependent on the gas and liquid superficial velocities, the results clarify the basis of the correlation between the liquid fraction and DP fluctuations in the range of conditions analyzed
Keywords
Inline two-phase flow metering, orifice plate, transient two-phase flow, differential pressure fluctuation, gasliquid flow visualization
