In earlier post "Mal-Distribution of Phases at T-Junction Phenomenon", there were several mal-distribution phenomenon shown. In this post there is another phenomenon where engineer may not see or feel it and it may not has any consequence. It is flow preferential and stagnant liquid phenomenon in a inclined splitting tee.
Taitel et al (1999 & 2003) has investigated two phase flow with common inlet, split at impacting T-junction, flow in inclined parallel pipes and merge at common outlet. Flow splitting of gas and liquid in four (4) parallel pips was investigated. Experimental results were obtained for 0°, 5°, 10° and 15° inclinations.
For the horizontal case (0°) the flow takes place in all of the 4 pipes, usually with an "approximately" even splitting. For the inclined pipes various flow configuration could take place. For low liquid and gas flow rates the two-phase mixture prefers to flow in a single pipe while stagnant liquid fills part of the other three (3) pipes. As the flow rates of liquid and gas increase, flow in two, three and eventually in four pipes takes place.
For the horizontal case (0°) the flow takes place in all of the 4 pipes, usually with an "approximately" even splitting. For the inclined pipes various flow configuration could take place. For low liquid and gas flow rates the two-phase mixture prefers to flow in a single pipe while stagnant liquid fills part of the other three (3) pipes. As the flow rates of liquid and gas increase, flow in two, three and eventually in four pipes takes place.
This has provided some insight and idea to the designer and operator, there is a minimum flow for two phase flow in parallel pipes. Under turndown operation, there is possible flow in single pipe while liquid column stagnant in the other pipe. Whenever increase production, it shall be gradually increase to avoid large liquid volume feed to the downstream equipment and pipe failure due to slugging flow in downstream pipe.
Another potential issue is present of heavy sand in the two phase flow. Heavy sand will tend to stays and accumulates in the stagnant liquid and potentially partially block the pipes. Therefore, this stagnant liquid phenomenon should be checked and taken care during design and operation phase.
- Mal-Distribution of Phases at T-Junction Phenomenon
- Problems Caused by Two Phase Gas-Liquid Flow
- Slugging & Slugcatcher
- Liquid Slug Stabiliser - Another type of slugcatcher
- Assess Potential Piping Failure Due to Valve Quick Opening with Two-Phase Vapor Liquid
- How Fluid Characteristic affect 2 phase Relief via PSV on Liquid filled Vessel Exposing to External Fire
- Facts about Erosion & Erosion-Corrosion
This is in fact informative.Thanks for sharing this type of the way.Hope to decide more.
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