The effect of between fibre coefficient of variation on the fibre fineness measured by the airflow.

The theory of the Airflow instrument is based on the theory of fluid flow through porous beds. This theory predicts that in conditions where the mean hydraulic radius of the pore space within the bed is constant, but the distribution in the mean hydraulic radii of individual pores varies, then the fluid now will also vary, all else remaining equal. In developing the Airflow instrument for the estimation of the mean fibre diameter of wool, Anderson and Warburton, demonstrated that theoretically the Airflow instrument is sensitive to variation in estimated diameter for samples that had the same projection microscope mean diameter, but different coefficients of variation in diameter. This theory is widely accepted, and is widely cited by various researchers. However there are no reports of experimental verification of this effect for the Airflow instrument. The development of the theory is described and an experiment has been conducted that confirms the theoretical predictions of the effect of Coefficient of Variation on the estimates of fineness obtained by the Airflow instrument.