Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.
The numerical results from a simple computational fluid
dynamic model of a forced air agricultural produce cooling
tunnel are compared with experimental measurements made on
a full scale tunnel. The experimental tunnel consists of four
pallets of produce each holding a number of boxes arranged in
a specified, but non-uniform stacking order. The tunnel is
located in a large cold storage room while the cold air is drawn
at a steady rate through the boxes using a large axial flow fan.
The time dependent temperature and pressure values are
experimentally determined at a number of strategic locations
within the tunnel. The experimentally determined values of the
tunnel pressures as well as the produce temperature as functions of time are plotted in a non-dimensional manner. These are then
compared with the results of the computational fluid dynamics
model. In the model the boxes filled with the agricultural produce, cucumbers in this case, are approximated using porous jumps for the boxes and a non-isotropic porous media model
with empirically determined coefficients for the produce. A
commercially available finite volume package is used to solve
for the time dependent temperature, pressure and flow field.
The discrepancies between the experimental and numerical
results are discussed and suggestions made for improving the numerical model.