2012 AIChE Annual Meeting

(142cc) A Rivulet Flow Model for Wetting Efficiency in Packed Beds


Packed towers are widely used in process industries in unit operations such as distillation, absorption, water cooling and catalytic gas-liquid reactions in which flowing gas needs to be brought into intimate contact with liquid flowing on the particles in the form of rivulets or films. The width of rivulets increases with increase in liquid flow rate and eventually the liquid film spreads all over the surface of the particles.Wetting efficiency, defined as the ratio of gas-liquid contact area to the particle surface area, directly affects the mass transfer rates in packed towers. It has been observed that wetting efficiency can be less than one depending on the operating variables (such as pressure, temperature, gas and liquid flow rates), system variable (such as density, viscosity, surface tension) and equipment variables (such as type of liquid distributor, particle shape, size and materials of construction). Rivulet flow on an inclined plane surface is analyzed through the concept of friction factor to develop a correlation for the width of rivulets as a function of liquid flow rate. This is extended to estimate wetting efficiency in packed towers. Literature data are used to validate the model equations. Inertial forces dominate over the viscous and surface tension forces in determining the wetting efficiency in packed towers. 
See more of this Session: Fluid Mechanics Poster Session

See more of this Group/Topical: Engineering Sciences and Fundamentals