Lockhart–Martinelli parameter

The Lockhart-Martinelli parameter is a dimensionless number used in internal two phase flow calculations. It expresses the liquid fraction of a flowing fluid. Its main application is in two-phase pressure drop and boiling/condensing heat transfer calculations.

It is defined as:

$\chi ={\frac {m_{l}}{m_{g}}}{\sqrt {\frac {\rho _{g}}{\rho _{l}}}}$

where:

• $m_{l}$ is the liquid phase mass flowrate

• $m_{g}$ is the gas phase mass flowrate

• $\rho _{g}$ is the gas density

• $\rho _{l}$ is the liquid density