Pressure difference across an aerated seed bulk for some common duct and store cross-sections

Abstract Bulk seed in store is often aerated for preservation purposes. The design of the associated fan and duct system is dependent upon estimation of the pressure difference across the bulk for a given airflow and duct and store geometry. Conformal mapping techniques are use to predict the component of pressure difference arising from the linear term in Ergun's equation, and the components arising from the square-law term are estimated by assuming radial flow near the duct and parallel flow remote from the duct. The formulae derived in this paper are applicable to most common duct store situations. The required resistance coefficients are given for airflow through 27 different seeds.