Two-Phase Flow with Boiling

When a liquid at its boiling point flows in a pipe, the pressure decrease due to friction will cause the pressure of the liquid to fall below its saturation pressure, and the liquid will boil. This type of flo i, called flashing flow, is important in the design of boilers, steam condensate lines, ete. 

In gas-liquid flows, numerous different flow patterns are possible, depending on the gas and liquid flow rates and properties and on the direction of the flow relative to the direction of gravity.  

For such flows the pressure drop due to friction heating of the fluids is 

Numerous empirical correlations are available for predicting the pressure drop, holdup, and slip velocity for such systems. These are not nearly as reliable as the pressure-drop correlations for single-phaise flow. 

From the data given in Fig. 14.2, prepare a plot showing the average density of the fluid in the tube p giz z ), and p S versus QJQ  

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