Iranian Journal of Chemical Engineering (IJChE)

Abstract Liquid Composite Molding (LCM), particularly the Resin Infusion (RI) process, has become an attractive manufacturing technique for producing lightweight composite vessel hulls with improved structural performance and reduced production costs. Nevertheless, achieving rapid and uniform resin impregnation while preventing dry spots and premature gelation remains a major challenge. This study presents a numerical investigation of the resin flow behavior in the manufacturing of small composite vessel hulls using a two-phase computational fluid dynamics model based on the Level-Set Method. Five resin injection configurations, including cylindrical, fishbone, radial, parallel, and alternating arrangements, were systematically evaluated in terms of the resin flow pattern, filling time, pressure distribution, and gelation behavior. The numerical model was validated against an analytical gelation-time correlation, resulting in the prediction errors of only 2.60% for the cylindrical configuration and 1.35% for the fishbone configuration. Compared with the conventional cylindrical arrangement, the fishbone configuration reduced the gelation time from 127 min to 96 min, corresponding to an improvement of approximately 24%, while achieving complete mold filling before gelation. Among all investigated strategies, the alternating and radial configurations exhibited the shortest filling times of approximately 30 min and 35 min respectively, whereas the parallel configuration required nearly 120 min. Furthermore, the cylindrical configuration filled only about 90% of the mold before gelation. The results demonstrate that optimized inlet configurations significantly improve the resin distribution uniformity, reduce filling time, and enhance manufacturing efficiency, providing practical guidelines for the design and optimization of resin infusion processes for composite marine structures.

Abstract The impact of bed loading on minimum spouting velocity (ums) of polydispersed TiO2 particles was studied in a conical fluidized bed. The experiments were performed at different bed loadings according to Gaussian and narrow-cut particle size distribution (PSD). The bed consisted of simple-agglomerates in size range of 30-90 µm belonging to Geldarts’ group A classification. The effect of PSD and interparticle force (IPF) on the predicted ums and hysteresis in the pressure profiles were studied through a combination of computational fluid dynamics and discrete element method (CFD-DEM). The experimental data showed that the choice of bed with Gaussian PSD-type led to more accurately predicting ums than the narrow-cut particle PSD. The impact of IPF on the expected ums became more critical than the PSD type because of an increase in bed loadings. The lowest deviations the results were obtained in the low bed loadings, which is confirmed the accuracy of simulation results. The simultaneous effects of PSD-type and IPF led to a change in the fluidization behavior of the bed. The bed with narrow-cut PSD has a hydrodynamic behavior similar to spouting and slugging regimes, while the fluidization quality of the bed improves by fine particles.