MIST DEPOSITION ONTO HAIRY ROOT CULTURES - AEROSOL MODELING AND EXPERIMENTS

We analyzed the applicability of the standard models for aerosol depos ition in randomly packed fibrous filter beds to mist deposition across a bed of hairy roots in the nutrient mist bioreactor. Although the as sumptions inherent in the models are met on a local level, the overall structure of the root bed introduces some uncertainty into the correc t choice of root packing fraction and gas velocity required by the mod el. For reasonable parameter values, the minimum in the deposition eff iciency curves is close to the peak in the mist number and mass distri butions, and good penetration of the root bed is possible. We then mea sured the deposition of:mist across a packed bed of Artemisia annua tr ansformed roots as a function of droplet size; bed length, and gas now rate at a root packing fraction alpha = 0.5. We compared the experime ntal measurements with the predictions of the aerosol deposition model and found good agreement between the measured and predicted values fo r the diameter where the deposition efficiency across the bed is 50%, D-0.5. Agreement between the model and the experiments broke down when the now rate was increased to the point where the creeping now assump tions were no longer valid.