Optical flow profiling method for visualization and evaluation of flow disturbances in agricultural pneumatic conveyance systems

Pneumatic conveying is widely used for transporting granular materials and agricultural products. Traditional flow visualization methods are used extensively in experimental fluid dynamics but have not been commonly used with agricultural products as the flow seeding particle. A flow visualization method that can provide qualitative flow visualization images and quantitative values to describe the flow behavior would be helpful in understanding physical design changes made to agricultural pneumatic conveying systems. The optical flow profiling method developed provides a descriptive visual interpretation of the behavior of the fluid and particles, both upstream and downstream of a 25 mm spherical obstruction. The sphere was attached to the bottom of an acrylic air-line that was conveying wheat particles at an air speed of 20 m/s and a mass flow rate of 5.5 kg/min. Particle occurrence probability density maps were developed to describe the probability of a wheat particle being present in a particular location of the conveying line. The data contained in these maps was used to determine the centroid of the distribution and to plot the change in the cross-sections over the test area of the pneumatic conveying system.