Location: Aerial Application Technology Research
Project Number: 3091-22000-037-004-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2018
End Date: Sep 30, 2022
Objective:
To use Computational Fluid Dynamics (CFD) to simulate primary, from the hydraulic atomizer, and secondary breakup, from air shear, of agricultural sprays nozzles used in agricultural aviation application scenarios. Results of this work will aid in not only numerical understanding of this interaction of hydraulic atomizers and air shear breakup but allow for future work of developing nozzles that are designed specifically for ag aviation applications.
Approach:
This project will use the ANSYS Fluent simulation package to simulate
Current nozzles will be scanned with a high resolution 3d scanning technology, then imaged by use of macro high-definition digital camera along with a relative object for sizing. The 3d scan and image will be used to create as accurate of 3d model as possible for simulation. That 3d model will be brought into the ANSYS Fluent simulation package where a technique known as VOF-to-DPM will be used. VOF, or Volume of Fluid, is a numerical approach based on an Eularian method which determines each cells state in the gas/liquid multiphase state. Based on user input, once a ligament breaks off of the liquid portion and becomes close to s sphere, the model transitions that into the DPM, or Discrete Phase Model, which is based upon LaGrangian tracking of the particle. This method allows for better particle tracking of simulated droplets as well as speeds up the simulation by reducing the cells necessary for computation.
While simulations are being performed, the nozzle being simulated will be analyzed in a wind tunnel measuring droplet size and droplet velocity at a certain plane. This information along with high-speed imagery will aid in ensuring that the simulated model is within an acceptable range of error to the real life nozzle. Once the simulation is validated, additional solutions can be simulated and then tested for simulation accuracy. This will enable a more robust final model to be developed.
