This paper deals with the on-line sizing of small diameter glass fibers (i.e. d < 30 mm) produced for textiles and reinforcement applications. Two models based on the Lorenz-Mie Theory are introduced to predict the basic light scattering properties and the response of a phase Doppler interferometer (PDI) to the sizing of infinite glass fibers. Among other parameters, these models take into account particular effects such as the fiber×s single-axis birefringence and the fiber×s refractive index dependence on its cooling rate (i.e. diameter). Both effects have a weak influence on the mean response of the PDI but a strong influence on the resonance structures of its phase-diameter relationship. Two optical set-ups were selected from a numerical optimization procedure and tested experimentally. Experimental results are presented demonstrating the validity of the models and the ability of the developed PDI set-ups to study some features of the fiber drawing-process: fluctuations of the fiber diameter when the nozzle is submitted to a convective perturbation and, when the fiber take-up velocity is modulated, the detection of hollow fibers.
The scattering of a finite beam by an ensemble of infinite cylinders, with a spatial orientation function of the depth, is simulated by using a Monte Carlo type code, including multiple scattering effects. The properties of the scattered light collected by detectors, such as the spatial distribution of intensities, are predicted, taking into account the polarization dependence.
The phase-Doppler technique, allowing one to measure velocities and sizes of individual spherical particles in moving flows, is a very popular technique. Nevertheless, the bulkiness of the device and the need for accurate adjustments still impose restrictions in use in a large number of industrial situations. We present here a miniature phase-Doppler probe in which the emitting and collecting units are assembled in a compact way. The performance of the device is numerically and experimentally demonstrated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.