A well-controlled ventilation rate is essential to provide animals and plants in livestock houses and greenhouses with good environment while minimizing additional heating and cooling cost. The quantification of ventilation rate is crucial in terms of control of indoor air quality and emission of pollutants. Especially in naturally-ventilated buildings, measuring the ventilation rate is more elusive because of dynamic and complex air flow patterns induced by natural wind.
WHY DO WE NEED CFD SIMULATION?
WHAT IS "SYS" ?
“SYS (Simulate YourSelf)” is a CFD solution to automate pre, main and post processes of computational fluid dynamics simulations and to analyse ventilation performance of a naturally ventilated agricultural buildings
HOW DOES IT WORK?
OpenFOAM and ParaView Python were used for CFD simulation and visualisation respectively because they are free and open source software. The simulation tool was developed using Microsoft Visual Basic (VB) and Python to provide automation of general processes of the CFD simulation, such as building geometry, meshing and computing, and the GUI for users. Based on the input by the user, a computational domain with a cylindrical shape was built to realise 16 wind directions and filled with 3D meshes using the SnappyHexMesh technique. Two new steady-state solvers that involved physiological models for animals and plants were developed, and used to compute incompressible turbulent buoyant flows. A solver to calculate the ventilation effectiveness, such as the local mean age (LMA) and the local mean residual-life-time (LMR), was also developed and included in the simulation tool. The simulated results were shown to the user by the interactive visualisation interface based on the Visualisation Toolkit (VTK) source.
The final simulation results are shown as a report that describes ventilation rates at each ventilation openings and the overall ventilation rate, and as a 3D visualisation through the 3D interactive visualisation window. in the visualisation window, the user can zoom in, zoom out, move and rotate the viewpoint by keyboard and mouse. The LMA, LMR, velocity, pressure, temperature, turbulence quantities and airflow vectors can be displayed on the sliced plane, which can be controled by the user.
Program files (No installation version)