Dispersion of pesticides from a naturally ventilated greenhouse: A CFD approach
A methodology of application of a numerical technique in order to simulate the dispersion of pesticides from greenhouses is presented. The proposed simulation approach is based on preliminary calculations that concern the greenhouse-block located in the University of Thessaly near Volos, on the coastal area of Eastern Greece. A 3D simulation model was developed using the commercial CFD code Fluent with the realizable k-ε turbulence model in order to simulate the air flow inside and around the experimental greenhouse. The ventilation process, through which the pesticide pollutants are emitted from the experimental greenhouse's side openings, was analyzed by simulating the dispersion of a tracer gas (Nitrous Oxide, N2O) which was used for the first sequence of experiments. The simulation results provided useful information about the dispersion of N2O around the experimental greenhouse, showing that wind characteristics dominate both the ventilation rate and dispersion of the tracer gas. Through this approach the determination of the critical points, where the measurement instruments have to be located during the experimental process are identified according to wind velocity and direction. In addition, useful conclusions were obtained concerning the set up of simulation model, showing how to improve the accuracy of computational predictions.