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PRCI PR-92-70
- Drag Reduction in Two-Phase Flow
- Report / Survey by Pipeline Research Council International, 01/01/1977
- Publisher: PRCI
$6.00$12.00
L11477e
University of Tulsa
Need: Drag reduction in single-phase and in two-phase slug flow is well known and fairly extensively documented. However, research on drag reduction in two-phase mist or annular-mist flow such as encountered in wet gas transmission lines was non-existent.
Result: The initial objective of this project was to determine the feasibility of drag reduction on two-phase mist flow. Subsequent objectives were to screen available hydrocarbon soluble drag reducers and to develop correlations for predicting drag reduction behavior when natural gas and a hydrocarbon liquid flow in pipes with a drag reducer.
Benefit: Drag reduction in two-phase annular-mist flow results primarily from a reduction in the liquid phase contribution to the two-phase pressure gradient. This is a result of reduced friction losses in the liquid film on the pipe wall and possibly to reduction in energy loss due to deformation of liquid drops in the gas phase and inhibited liquid entrainment and annular film wave formulation. Attempts to correlate the two-phase drag reduction data with friction velocity, as is done for single-phase liquid flow, were unsuccessful since drag reduction was found to depend not only on friction velocity, but also on liquid loading and pipe size. However, the use of Lockhart-Martinelli parameters to correlate the drag reduction data was successful. Experimental studies of drag reduction and degradation in large-scale test facilities are extremely difficult and time consuming. Nevertheless, additional studies involving other drag reducers, effects of water in the liquid phase, and more extensive evaluation of the effects of pipe diameter, liquid loading and friction velocity on two-phase drag reduction are needed. The final test of the value of using drag reducers in pipelines to reduce pressure loss or increase capacity can come only from conducting field tests.
University of Tulsa
Need: Drag reduction in single-phase and in two-phase slug flow is well known and fairly extensively documented. However, research on drag reduction in two-phase mist or annular-mist flow such as encountered in wet gas transmission lines was non-existent.
Result: The initial objective of this project was to determine the feasibility of drag reduction on two-phase mist flow. Subsequent objectives were to screen available hydrocarbon soluble drag reducers and to develop correlations for predicting drag reduction behavior when natural gas and a hydrocarbon liquid flow in pipes with a drag reducer.
Benefit: Drag reduction in two-phase annular-mist flow results primarily from a reduction in the liquid phase contribution to the two-phase pressure gradient. This is a result of reduced friction losses in the liquid film on the pipe wall and possibly to reduction in energy loss due to deformation of liquid drops in the gas phase and inhibited liquid entrainment and annular film wave formulation. Attempts to correlate the two-phase drag reduction data with friction velocity, as is done for single-phase liquid flow, were unsuccessful since drag reduction was found to depend not only on friction velocity, but also on liquid loading and pipe size. However, the use of Lockhart-Martinelli parameters to correlate the drag reduction data was successful. Experimental studies of drag reduction and degradation in large-scale test facilities are extremely difficult and time consuming. Nevertheless, additional studies involving other drag reducers, effects of water in the liquid phase, and more extensive evaluation of the effects of pipe diameter, liquid loading and friction velocity on two-phase drag reduction are needed. The final test of the value of using drag reducers in pipelines to reduce pressure loss or increase capacity can come only from conducting field tests.
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