[Hailish]

Currently, I'm embarking on the CFD modeling aspect of my study, which is about modeling the spray drying of milk under different operating conditions. I'm using ANSYS Fluent version17.2. My case involves injecting milk droplets at a nozzle to a hot air stream whereby the droplets get evaporated and the remaining solid particles leave the spray dryer at an outlet. The milk can be considered as a mixture of water (evaporating part) +solids (non-evaporating part). So, the modelling will involve Eulerian-Lagrangian approach to track the droplets field across the flowing hot air stream, while exchanging heat and mass via two-way coupling. I meshed the spray dryer model (passed orthogonal quality parametres), I brought it to Fluent. At the first instance, I modeled the airflow stream without the droplets, it predicts well. the configurations was as follows. SST k-omega for turbulent, Coupled method for pressure-velocity coupling, Least squares cell based for spatial discretization. The problem arrived when i try to inject the droplets. I turned on the species transport model, i created an injection using droplets as particle type. I edited the droplet properties to convert that of water liquid to milk. Finally, the particles could be tracked through the flow, but there is no evaporation in any of the particles tracked. While i try to solve this by using the multi-component particle type option, It doesn't have an option to specify the evaporating species. Reading on the CFD Forum, I've later learnt that, for Fluent to calculate evaporation on multicomponents mode, one has to hook a UDF code. But, since I'm new to this area, I found it difficult looking for Fluent UDF codes for this particular case, and I don't have any idea about as to how to hook them to ANSYS Fluent. Your guidance and assistance is of paramount importance. Thank you very much in advance