ASABE Technical Library - Abstract

Abstract. With increased milk production and potential climate warming, keeping dairy cows more comfortable with cooling fans to lessen the effects of heat stress is an important goal for dairy farmers. As a result of this need a computational fluid dynamics (CFD) model that characterizes airflow generated by cooling fans as used in a freestall dairy barn was developed. In this model, the fan action was represented by a momentum source with a fixed velocity. Validation of the flow model was performed by measuring air velocities at ten selected locations in a commercial freestall barn, and the results showed that CFD is able to predict flow fields with an acceptable accuracy. Flow simulations were carried out to study the effect of the fan mounting angle on the flow patterns for both lying and standing cows in the stalls and standing cows at the feed bunk. Optimal design was conducted to determine the fan orientation through checking the velocities at specified planes above cows with the model. The critical exit velocity of each fan was obtained from simulation tests to meet the requirement of the minimum air velocity of 2 m/s across the cows.

..