  For a well-stirred multiphase fluid systems the mean interface area per unit
volume, $(\delta{S}/\delta{V})$, is a significant characteristic of the system
state. In particular, it is important for the dynamics of systems of immiscible
liquids experiencing interfacial boiling. We estimate the value of parameter
$(\delta{S}/\delta{V})$ as a function of heat influx $\dot{Q}_V$ to the system.
