A method developed for particle locating and advancing in nonorthogonal curvilinear grids is presented. The method is uniformly applicable for deforming as well as fixed Eulerian grids. The method is equally applicable to coupled as well as uncoupled two-phase flows. Guidelines are presented on which the present and previous schemes are evaluated. The algorithm yields a generalized and efficient method and is being used in practical applications. The accuracy of the method is demonstrated by verifying with analytical and experimental data.

In this study, a computational fluid dynamics (CFD) model is applied to study the airflow patterns inside the commingling jets, for different configurations. The CFD package, FLUENT 6.1, is used to predict the two-dimensional flow field inside a yarn channel. The parameters viz. velocity profile, pressure gradient, and air particle trajectory, obtained from this CFD analysis give important information for further analysis. The design parameters of commingling jets are related to the flow characteristics and their effect on the structure and properties of Glass/Nylon commingled yarns. The results show that the number of air orifice and the angle of orifice have significant effect on the airflow profile inside the jet and consequently on the structure of the commingled yarns. The jet orifice angle affects the axial velocity. The effect of air pressure is also important, since the nip frequency of commingled yarns is a function of the speed of rotation of the vortex and it is observed that with increase in air pressure, axial and tangential velocities in the nozzle increase. This work shows that, the CFD modeling can be used to optimize nozzle design parameters to develop commingled yarns with better properties.

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