Lockhart–Martinelli parameter

The Lockhart–Martinelli parameter ($\chi$) 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:

$\chi = \frac{m_\ell}{m_g} \sqrt{\frac{\rho_g}{\rho_\ell}},$

where

• $m_\ell$ is the liquid phase mass flowrate;
• $m_g$ is the gas phase mass flowrate;
• $\rho_g$ is the gas density;
• $\rho_\ell$ is the liquid density.

See also

• Wet gas