Low Pressure Loop
Picture: The inclineable beam with the rectangular test section above the circular pipe test sections
The Low Pressure Loop is a multiphase flow loop used to study phenomena in gas-liquid or liquid-particle flow, where the gas density is considered to be of minor importance, therefore justifying the use of atmospheric air.
The design and instrumentation of the Low Pressure Loop meets the accuracy requirements for fundamental studies of multiphase flow phenomena.
The loop operates with air as the gas phase and normally with water as the liquid phase. A low aromatic white oil may be used as the liquid phase, but it must have a high flame point since the loop is not Ex-proof.
The loop consists of a test section, mounted on an inclinable beam, a return section, a particle extraction system, a combined separator and storage tank, a low shear liquid pump and a gas supply system. We have several test sections to choose between; either 25, 60 or 100 mm circular pipes or a rectangular channel. Apart from the gas inlet and metering sections, most of the piping is in transparent PVC.
The test rig has three typical operating modes:
1. Air-liquid flow
2. Liquid-particle flow
3. Liquid-liquid flow in a closed continuously circulation mode
Pressure : Atmospheric
Gas phase : Air
Liquid phase: Water or model oil w/flash point above 50oC
Test section: Circular pipes, D=27/60/100 mm, rectangular, HxW= 50x300 mm, length 15-20 m, incl. +/- 10o
Pipe material: PVC/Perspex/Latex
Gas flow rate: 150 m3/h
Liq. Flow rate: 60 m3/h
Data logging :LabVIEW
In the D=60 mm pipe, the maximum superficial velocities are Usg=15 m/s and Usl=6 m/s.
The flow loop is permanently equipped with instrumentation necessary for basic multi-phase flow experiments; flow meters, temperature sensors and press-ure gauges that are used to monitor the flow conditions during an experiment. The gas flow rate is measured by a vortex meter. The liquid flow rate is measured with either a Coriolis meter or with an electromagnetic flow meter.
In addition, the test section of the flow loop is equipped with advanced scientific instruments:
- Gamma-densitometer for measurement of liquid holdup
- High Speed Video camera
- X-ray CT for measurement of holdup, fluid distribution and interface structures
- Laser Doppler Anemometer and PIV for detailed velocity & turbulence measurements
- Traversing gamma-densitometer for particle concentration profiles
The small picture shows the traversing gamma instrument used for particle concentration profile masurements.
Examples of flow phenomena studied in the test facility are:
- Effects of drag reducers (DRA) in multiphase flow
- Mechanisms in suspension flow
- Slug flow in high viscosity liquid