Particle image velocimetry measurements of stratified gas-liquid flow in horizontal and inclined pipes

Abstract

The main objectives of this work is to produce detailed velocity profile measurements over a range of operating conditions of two phase gas/liquid flow with low liquid fractions in horizontal and inclined pipes. The experiments are performed in a 15 m long stainless steel pipe section with internal diameter 56 mm at room temperature and atmospheric outlet pressure. Exxsol D60 oil (viscosity 1.30 mPa s, density 793 kg/m 3), water (viscosity 0.89 mPa s, density 999 kg/m 3) and air (viscosity 0.018 mPa s, density 1.22 kg/m 3) are used as test fluids. The pipe inclination is changed in the range from 5° upward to 5° downward. The measurements are made at mixture velocity, 5 m/s for different inlet liquid fractions. The cross-sectional distribution of phase fractions is measured using a traversable single-beam gamma densitometer. The particle image velocimetry (PIV) is utilized in order to obtain non-invasive instantaneous velocity measurements of the flow field. Based on the instantaneous local velocities, mean velocities, root mean squared velocities and Reynolds stresses are calculated. The measured mean velocity and turbulence profiles show a strong dependency with pipe inclination. The present measurements show that PIV can be successfully used as a practical measurement technique for multiphase flow applications with potential to become even more powerful in the near future as digital camera technology progresses.

Turbulence statistics and flow structure in fluid flow using particle image velocimetry technique: A review

“…The interfacial shear, pressure fluctuations, turbulent fluid motion, and other effects observed in gas‐liquid flows produce interfacial instabilities and wave structure formation. A number of the PIV studies for gas‐liquid flows have reported difficulty in defining the precise position of the interface and in taking measurements close to pipe walls due to reflection at the interface and wall respectively . Various techniques have been employed to improve PIV measurements at the interface such as camera orientation, optical filters, fluorescent seeding, and the use of complementary measurement instrumentations such as pulsed shadow technique (PST) and planar laser‐induced fluorescence (PLIF) among others .…”

Numerical 3D simulation of developing turbulent stratified gas-liquid flow in curved pipes consisting of entrained particles through this type of flow

“…The two-phase flow measurements indicated expected behaviour for low flow rates, and very interesting features related to the turbulence structure at higher flow rates that led to wavy interfaces. Inspired by ongoing approach, Vestøl et al [24] produced detailed velocity profile measurements over a range of operating conditions of two phase gas/liquid flow with low liquid fractions in horizontal and inclined pipes. The experiments were implemented in a 15 long stainless steel pipe with internal diameter of 56 at room temperature and atmospheric outlet pressure.…”