Measurements and Visualization of the Fluid Field of the Plume from an Animal Housing Ventilation Fan

Manqing Ying,Lingjuan Wang-Li,Jack Edwards,Larry F Stikeleather

doi:10.4236/jep.2017.811080

Abstract

Various dispersion models have been developed to simulate the fate and transport of air emissions from animal housing systems to meet the increasing need for knowledge in this area. However, the accuracy of the models may be challenged due to the unknown plume rise and plume shape. This paper reports a combination of theoretical and field study of the plum rise and shape of air flow from a ventilation fan commonly used in mechanically ventilated animal houses. The theoretical modeling of the plume shape was conducted using a commercial Computational Fluid Dynamics (CFD) package named FloEFD; the field measurements of the plume field was conducted using five 3D ultrasonic anemometers to simultaneously measure the air flow in the plume at various locations (four heights and five downwind distances). The TECPLOT package was used to visualize the plume flow field based upon anemometer measurements. While the plume shapes were found to be left-shifted by the CFD model and TECPLOT visualization, the magnitudes of the 3D wind velocities from field measurement were found to be significantly larger than those from CFD model. The plume field measurements indicated that the plume of a 0.6 m (24-inch) ventilation fan had a depth about 9 m, a width about ±6 m, and a rise (lifting) beyond the highest measurement point, 4.88 m (16 ft).

Highlights

The TECPLOT package was used to visualize the plume flow field based upon anemometer measurements
While the plume shapes were found to be left-shifted by the Computational Fluid Dynamics (CFD) model and TECPLOT visualization, the magnitudes of the 3D wind velocities from field measurement were found to be significantly larger than those from CFD model
The plume field measurements indicated that the plume of a 0.6 m (24-inch) ventilation fan had a depth about 9 m, a width about ±6 m, and a rise beyond the highest measurement point, 4.88 m (16 ft)

Summary

Introduction

It has been reported [1] that there were 450,000 animal feeding operations (AFOs) in the United States. The Gaussian dispersion model was originally developed based upon observations of industrial “stack” emissions with vertical momentum and thermal buoyancy [11]. The accuracy of the Gaussian dispersion model may be challenged when it is applied for assessing dispersion of air emissions from animal housing system where there is lack of vertical momentum and sufficient “stack” height. This challenge mainly comes from unknown of plume rise and plume shape of the horizontal emissions from the housing ventilation fans

Objectives

Methods

Results

Conclusion