Agriculturae Conspectus Scientificus, Vol 64, No 3 (1999)

Composed air flow in pesticide spraying


Pages: 161-177


Quality and quantity of the droplets deposition depend almost only on the quantity of kinetic energy and on the turbulence of the air flow. Therefore it is especially important that the kinetic energy dissipates in the greatest extent inside the tree crowns. The form of the air flow, dissipation of energy and the turbulence intensity in the air flow can be directed by the use of composed air flows. Our research are performed for single air flow and for more variants of composed parallel and converging double flows. The influence of the distance and angle of convergence of two flows upon the form of the composed flow and dissipation of energy has been studied. It has been stated that the width of composed air flows increases slower than the width of the single air flow and that the distance between outlets does not essentially influence its changing. On contrary the convergence angle influences the position of the point of the biggest contraction and of total joining of two flows in the single one. The kinetic energy in the composed flows drops also faster than at the single one. This dropping is especially large at the flows with bigger outlet distances and at the big convergence angles. As for instance at the distance at 3,5 m from the outlet the parallel flows contain only 44 to 75 %, and the convergent flows only 19 to 50 % of the kinetic energy of the single flow.


composed air flow; fluid mechanics; plant protection; spraying

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