Comparative analysis of the multiphase flow in a spray drying tower

The multiphase flow investigated was a spray of water in a spray tower of industrial spray drier design and scale. All the experiments and the simulation calculations were done under operating conditions of practical application. The investigations have the character of model experiments cause of the restrictions on the `model' fluid water and the low level of temperature disregarding the processes of mass and heat transfer. The main aims of this work were: i) To adapt the measurement techniques on the requirements of the measurement situation in the spray tower. ii) To analyze experimentally the multiphase flows in terms of drop size and velocity distributions and the profiles of their representative parameters in the spray cone. iii) To compare these parameters with the results of the simulation by means of the FLOW3D-code. The experimental strategy is outlined as follows: With the help of Laser Light Sheet method (LLS) was found out the general shape of the drop flow. The spray was illuminated in different intersection planes of light sheets e.g. to get information of the spray angle. By means of Diffraction Size Metry (DSM) drop size distributions were obtained for locally defined measurement sections. Finally a Phase-Doppler-Anemometer (PDA) was used to get the 2-dimensional drop size/velocity distribution with high local resolution. LLS and DSM served so as additional and reference methods to highlight the plausibility of PDA-results. The latter ones i.e. profiles of velocity means will be compared with the simulation results. The experimental and theoretical investigations give agreeing and mutual complimentary results. Remaining discrepancies are due to still existing restrictions of the PDA-method on one hand and a lack of complexity of the FLOW3D-model on the other.