$13.$ Which method is not used for flow regime identification in multiphase flow?

A$)$ Visual observation

B$)$ Pressure drop measurements

C$)$ Electrical conductivity

D$)$ Thermal conductivity measurement

$14.$ Volume fraction estimation in multiphase flows is critical for:

A$)$ Determining chemical reaction rates

B$)$ Estimating pressure drop and flow regime

C$)$ Predicting phase change temperatures

D$)$ Measuring fluid velocities

$15.$ The drift flux model is particularly useful for predicting:

A$)$ Temperature distribution in a reactor

B$)$ Phase distribution in multiphase flow

C$)$ Chemical reaction kinetics

D$)$ Solids dispersion in a liquid

$16.$ Which factor does not influence the modification of the drift flux model for gas$-$liquid flows in mini channels?

A$)$ Pipe diameter

B$)$ Phase velocities

C$)$ Ambient temperature

D$)$ Wall effects