Temperature, Density and Velocity Effects on Lint Moisture Transfer Rates

Moisture control during the harvesting, storage, and processing phases of cotton production is essential for producing a quality product. The objective of this study was to quantify the effects of relative velocity, temperature and density on moisture transfer rates for cotton lint during the drying or moisture restoration process. The air velocity, passing over, through, and around the sample was varied from 118 to 825 cc/s (0.25 to 1.75 ft 3 /min). This provided relative velocities from 5 to 35 cm/s. The density of the cotton lint was varied from .005 to .03 g/cc. Two air temperatures, 40 and 80
C, were used in the study. As expected, air temperature and lint density had a pronounced effect on moisture transfer rates. Increasing the cotton lint density resulted in significantly reduced moisture transfer rates. A generalized equation consisting of temperature, relative velocity, and density was developed for predicting the coefficient D (containing diffusivity) for cotton lint exposed to the experimental conditions.