Hatta number
The Hatta number (Ha) was developed by Shirôji Hatta, who taught at Tohoku University. It is a dimensionless parameter that compares the rate of reaction in a liquid film to the rate of diffusion through the film. For a second order reaction (rA = k2CBCA), the maximum rate of reaction assumes that the liquid film is saturated with gas at the interfacial concentration (CA,i); thus, the maximum rate of reaction is k2CB,bulkCA,iδL.