$13.$ What parameter is critical in determining the flow regime in a multiphase flow?

A$)$ Fluid density

B$)$ Temperature

C$)$ Superficial velocities of the phases

D$)$ Pipe diameter

$14.$ The drift flux model can be applied to analyze which type of flow in mini channels?

A$)$ Only single$-$phase flows

B$)$ Only gas$-$liquid flows

C$)$ Gas$-$liquid and liquid$-$liquid flows

D$)$ Only solid$-$liquid flows

$15.$ Bubble columns are primarily used for:

A$)$ Separation processes

B$)$ Heat transfer processes

C$)$ Gas$-$liquid reactions

D$)$ Solid$-$liquid mixing

$16.$ What aspect does the modification of the drift flux model for liquid$-$liquid flows in mini channels typically consider?

A$)$ Enhanced gravitational effects

B$)$ Reduced interfacial tension

C$)$ Increased surface tension effects

D$)$ Decreased viscosity effects