A theoretical model for mass and energy considerations in microclimate modification by sprinkling

Modification of the microclimate by irrigation sprinklers involves complex interactions among thermodynamic and transfer properties, system characteristics, and ambient conditions. A need exists for a better understanding of the theoretical background of these interactions. A theoretical model which accounts for the diffusion of heat and mass in stagnant air was developed for a two-dimensional radially axi-symmetric coordinate system. The governing equations were derived by application of equations for conservation of mass and energy. The finite element method using three-node linear triangular elements and linear interpolation functions was employed to obtain numerical solutions to the governing equations. Testing of the model was performed by comparing simulated results with proven analytical solutions as well as experimental data. An example of how the model can be adapted to a specific application is included for the case of heat and mass transfer from droplets in flight. Results showed that the model accurately simulates changes in both temperature and mass concentration of water vapor in stagnant air.