Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 7/29/2001
Publication Date: 7/29/2001
Citation: Barker, G.L., Laird, J.W., Pelletier, M.G., Holt, G.A. 2001. Temperature, density and velocity effects on lint moisture transfer rates. American Society of Agricultural Engineers. Paper No. 011141.
Interpretive Summary: Moisture affects every aspect of cotton harvesting and processing. Excessive moisture results in grade losses, fiber deterioration, and decreased machine performance, while low moisture can cause fiber breakage and results in operating difficulties. Moisture transfer rates for lint were determined as a function of lint density and air velocity using two temperatures, 40 deg C and 80 deg C. The air flow rates varied from 0.22 t 1.75 CFM through a 2.75 inch diameter pipe. Lint density was varied from 0.005 to .03 g/cc. As expected, lint density and temperature both had a very pronounced effect on moisture transfer rates, increasing the lint density reduced transfer rates. The lint moisture transfer rates were also enhanced by increasing the air velocity, although increasing the density greatly reduced the effect of air velocity within the range tested. A generalized regression equation was developed for predicting the effects of fair velocity, temperature, and lint density on cotton lint moisture transfer rates. This information will be used in conjunction with equilibrium moisture data to estimate the moisture content of harvested seed cotton during cotton harvesting and ginning.
Technical Abstract: 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 CFM). 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 deg 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.