Experimental investigation on the initiation and flow development of gas-liquid slug two-phase flow in a horizontal pipe

Effect of flow velocity on erosion–corrosion of 90-degree horizontal elbow

Influence of intermittent flow sub-patterns on erosion-corrosion in horizontal pipe

Two-phase flow regime identification in a horizontal pipe was realized based on the liquid phase velocity information and the machine learning method. Ultrasound Doppler velocimetry was employed to measure the liquid velocity. Statistical features extracted from the velocity time series data, such as mean, root mean square, and power spectral density, were used to realize real-time flow regime identification. In addition, two novel parameters—maximum velocity ratio and maximum velocity difference ratio—were proposed to identify plug and decaying slug flow. Different classification algorithms were employed to achieve a high identification accuracy. Moreover, transient flow regime identification with a fast response was realized based on two classification algorithms—long–short term memory and convolutional neural network. The results show that the accuracy of real-time flow regime identification based on a flow regime map can reach up to 93.1% using support vector machine, the maximum velocity ratio and maximum velocity difference ratio are effective in identifying plug and decaying slug flow, and transient flow regime identification under slug flow condition can be realized with an accuracy of 94% based on a convolutional neural network (CNN). Decaying slugs with long lengths confuse the CNN and are responsible for the error in identification. The results presented herein are expected to expand the available knowledge on two-phase flow regime identification.

Two-phase flow regime identification based on the liquid-phase velocity information and machine learning

Abstract Simultaneous Particle Image Velocimetry (PIV) measurements of stratified turbulent air/water flow in a horizontal pipe have been performed using small water droplets, d p ‾ = 6 μ m , as tracer particles in the gas-phase. This seeding technique ensures that the surface tension of the water layer remains unaffected upon contact with the tracer particles in the gas-phase and thus allows small scale interfacial structures, such as capillary waves to occur and evolve naturally. Experiments have been conducted in a 31 m long, 100 mm in diameter PVC pipe using air and water at atmospheric pressure as test fluids. For the purpose of validation of the experimental set-up and the suggested seeding technique, gas single-phase measurements were performed at Re D = 45 , 000 and compared to existing DNS results from the literature with similar Re-number, showing very good agreement. Two stratified flow cases, i.e. smooth and wavy, are extensively discussed with emphasis on the effect of the interface pattern on the gas streamwise turbulence profile u g ′ . A simple analysis using the u g ′ -profiles of 17 stratified flows suggests the presence of a correlation between the turbulence structure of the gas-phase and global flow conditions such as the pressure drop and the bulk velocity.

Jignesh Thaker

Papers

Characterization of two-phase slug flow sub-regimes using flow visualization

Influence of intermittent flow sub-patterns on erosion-corrosion in horizontal pipe

Transition of plug to slug flow and associated fluid dynamics

On intermittent flow characteristics of gas–liquid two-phase flow☆

On instantaneous pressure surges and time averaged pressure drop in intermittent regime of two-phase flow