Numerical Simulation of Airflow in Livestock Buildings with Radial Inlet

Bjarne Bjerg, Lars Soerensen


The purpose of this work is to inquire the potentials of a simplified method of modelling radial inlets in numerical simulation of airflow in mechanically ventilated livestock rooms. This simplified method is based on simulation of an angle section of the entire air volume with starting point in the centre line of the inlet. Using symmetry planes as boundary condition on the sides of the angle section, and grids including only one cell in the width direction, it is possible to include three-dimensional geometry in simulations nearly equally uncomplicated as twodimensional simulations.

Inside and close to the inlet the angle section method generates practically the same air velocities and pressure conditions as simulation of the entire room. At floor level the angle section methods generates air velocities that can be regarded as typical for the variety for velocities that occurs in a corresponding entire room simulation. Compared to entire room simulation the angle section methods reduce the required modelling time and calculation time with at least 80 and 95 percent, respectively, and consequently, it becomes practicable to inquire a relative large number of alternative solutions in order to develop suitable layout of radial inlet armatures. Further on the angle section method gives much better possibilities to increase grid density in order to investigate for possible grid dependency on simulation results.

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