Showing posts with label two-phase. Show all posts
Showing posts with label two-phase. Show all posts

Flow Regime Map for Two-Phase Flow

This Excel spreadsheet plots a flow regime map for the two-phase flow of liquid and gas in horizontal and vertical pipes.

Determining flow regime is important when calculating pressure drops and pumping requirements in the oil & gas industry, and chemical production. Additionally, some flow regimes are undesirable (such as slug flow, which can damage pipes through excessive vibration). Engineers will change pipe diameters and other process parameters so the flow regime is more favorable.

In the spreadsheet, simply enter the liquid and gas flowrates.


The spreadsheet will then plot the location of the flow on a flow regime map for horizontal and vertical pipes. The horizontal and vertical axes are the Gas Froude Number and Liquid Froude Number.

The spreadsheet uses the flow regime maps digitized from Shell DEP 31.22.05.11 (the "DEP" is short for Design and Engineering Practice")

Many flow regime maps have been developed by different researchers. For example, 
  • Mandhane et al (1974) published a map for two-phase horizontal flow
  • Hewitt and Roberts (1969) published a map for two-phase vertical flow
  • Taitel and Dukel (1976) published a map for two-phase horizontal flow
There are, however, inconsistencies in the definition of flow regimes in these different maps. For example, some maps give different flow regimes at the same conditions.

The horizontal and vertical maps given in Shell DEP 31.22.05.11 were developed by a single source, and have a consistent definition of flow regimes.  Therefore, engineers can compare potential flow regimes in horizontal and vertical pipes.



Calculating Two-Phase Pressure Drop with the Lockhart-Martinelli Correlation

The Lockhart and Martinelli correlation is commonly used to calculate the pressure-drop of two-phase flow in pipe. It's simpler than other methods, and is particularly suitable for low liquid and gas flows in small diameter pipes.

This Excel spreadsheet helps you calculate the two-phase pressure drop in a pipe.  It has several stages
  • First the pressure drops of the individual phases are calculated assuming that each phase is alone in the pipe (i.e. separated flow). 
  • Then, the Lockhart-Martinelli parameter is calculated. 
  •   Finally, the Chisholm (1967) correlation is used to calculate the total pressure drop.