Numerical and experimental study of internal flow field for a carbon fibertow pneumatic spreader

In this study, a three-dimensional (3-D) mathematical model of a fiber pneu matic spreader was successfully developed in the physical phenomena of the internal flow field by a far-field treatment at boundary conditions. The 3- D numerical analysis was carried out on incompressible fluid flows in the p neumatic spreader by using finite volume method combined with the k-epsilon turbulence model which solves Reynolds-averaged Naiver-Stokes equations. C haracteristics of the flow field in the spreader at different service condi tions are investigated by velocity and pressure distributions. Comparisons of numerical results with measured velocity and pressure distributions were made to determine the accuracy of the employed method. A good agreement wa s found in both qualitative and quantitative analysis. Fibers were spread o n 1:1-scale model of the pneumatic spreader at various fiber transporting r ates and air flow rates. Photography techniques were simultaneously used to record the procedures of fibers spread. The carbon fiber tow was easily sp read out at service conditions. The performance was better than prior studi es in one-dimensional orifice formulation. The results revealed details of the fiber spreading processes. Agreement among those results validated the assumptions inherent to the computational calculation and gave confidence t o more complex geometries as well as flow fields. In other words, the use o f numerical analysis in the internal flow field was useful for the fiber pn eumatic spreader design.