Page 517 - Standard Handbook Petroleum Natural Gas Engineering VOLUME2

Flow of Fluids 473

(6-883)

where X and Y are the same as the values for the stratified flow regime.
With these parameters, Figure 6-55o-d can be used to estimate the liquid
holdup in the liquid film H, for the annular flow regime.
The total liquid holdup in the annular flow regime is calculated as follows:
)

H, = Hu+( (6-89)
+ 'rg

Pressure Gradient
The friction factor for the liquid phase needs to be calculated first.

[16/Re, if Re, < 1,500

The fractional and gravitational pressure gradients are

=-[2fw,[l$)(5)] 4
(6-9 la)

and

Special Case for Low Liquid Holdup
For low values of the liquid holdup, the approach described below is recom-
mended. If H, < 0.002, then

(6-9%)
[16/Reg if Re, < 1,500

(tmt conrimrsd on pa@ 4 78)