The Hatta number (Ha) was developed by Shirôji Hatta, who taught at

Tohoku University , or is a Japanese national university located in Sendai, Miyagi in the Tōhoku Region, Japan. It is informally referred to as . Established in 1907, it was the third Imperial University in Japan and among the first three Designated National ...

. It is a dimensionless parameter that compares the rate of reaction in a liquid film to the rate of diffusion through the film. R.B. Bird, W.E. Stewart, E.N. Lightfoot, Transport Phenomena, 2nd ed. John Wiley & Sons, 2002 For a second order reaction (), the maximum rate of reaction assumes that the liquid film is saturated with gas at the interfacial concentration ; thus, the maximum rate of reaction is .

Ha^2 =  =  =

For a reaction order in and order in :

Ha =

It is an important parameter used in Chemical Reaction Engineering.

References

See also