Aerodynamic Removal of Native Dust from Cotton

Abstract

An aerodynamic model is considered to predict variation in the mass of native dust removed from cotton as a function of velocity of the crossflow of air approaching the fiber. The model incorporates the composition of native dust, the aerodynamic shielding of some particles on the fiber from the drag force, and the cross-sectional density of the exposed batt of fibers. Physical representation of the model is based on a limited number of discrete data points graphically depicted by straight lines between the points. Using the model to simulate aerodynamic removal of native dust from cotton, a graphic representation of the mass of dust removed versus air velocity is predicted to reveal a curve with multiple inflection points. These points correspond to release of different components of the dust (e.g., bract and leaf) from the fiber. The model is compared with an experiment. An actual plot of the amount of dust released from "good ordinary" cotton versus the air velocity approaching the fiber reveals the pre dicted multiple inflection points. The air velocities required for aerodynamic removal of the leaf and bract components of the dust from this cotton are, respectively, 25 m/ s (>50 mph) and 60 m/s (> 130 mph).