Numerical simulation of gas absorption to a thin liquid film over a rotating disk in the presence of simultaneous chemical reaction

The problem of gas absorption accompanied by a zero order or first order chemical reaction is examined. A numerical solution is developed to determine the bulk concentration and the mass transfer rate. The disk is rotated at a constant angular velocity and the liquid is introduced at the center of the disk. The film is formed by the radial spreading of the liquid along the surface of the disk due to centrifugal force. The physical processes are modeled by solving the equations for the conservation of mass, momentum, and species concentration and solving them numerically using appropriate boundary conditions. Results are presented in a nondimensional form using Sherwood number, dimensionless bulk concentration, Reynolds number, Ekman number and dimensionless reaction rate as parameters. In gas absorption with zero order chemical reaction, the bulk concentration decreased with increase in reaction rate but the Sherwood number did not change significantly. With an increase in Ekman number, the Sherwood number increased and the bulk concentration decreased. The Sherwood number is also seen to increase with Reynolds number. A similar trend was seen for gas absorption with a first order reaction, except that the Sherwood number increased with reaction rate.