Influence of spiral blade distributor on the airflow distribution influidisation systems via computational fluid dynamics analysis

Blade distributors have a huge potential to be widely used in fluidisation systems in the power generating, chemical, and mineral processing sectors. The use of slanted gas injection in the blade distributors would attain greater performance in the fluidisation systems. Previous studies have been carried out to address various constraints of conventional fluidisation systems. One of the concerns is that the distributor design can influence the bubble size and reduce the fluidisation performance. In addition, conventional fluidisation systems do not fluidise at one specific value that directly affects the bed behaviour. The pressure drop in conventional fluidisation is also inconsistent with the increasing air velocity, which affects the bed weight or bed moisture content. Therefore, the current study was aimed to assess the operational range of several types of distributors by focusing on the blade inclination angle and the pitch length of the spiral blade distributor. The current study also verified the velocity component of the airflow distribution using the current perforated plate distributor design. Furthermore, the optimum geometry of the perforated plate distributor was evaluated via the optimisation method, in particular, the low-pressure drop, uniform velocity, and high tangential velocity. Several methods have been proposed to achieve the goal outlined in this study. First, the numerical simulation of Computational Fluid Dynamics (CFD) was used to investigate the spiral blade distributor in the fluidisation system with varying pitch lengths (60 mm, 80 mm, and 100 mm) and various horizontal inclination angles (0°, 12°, and 15°). Second, the CFD was used to investigate the velocity characteristics of each velocity component, such as velocity magnitude, tangential velocity, axial velocity, and radial velocity, as well as the pressure drop of the spiral blade distributor configuration. Third, the extracted data were evaluated using statistical analysis based on mean values, standard deviation, and optimisation method, including the Full Factorial Design (FFD). The most significant finding in this study that represents the optimum design of the spiral blade distributor fluidisation system was the 12° inclination angle with a pitch length of 100 mm. The findings in this study showed that the optimum design formed a velocity uniformity with a higher tangential velocity of 21.018 m/s with a low standard deviation of 2.996% and a lower pressure drop of 3593.59 Pa. Furthermore, the extended analysis using the Analysis of Variance (ANOVA) indicated that the blade inclination angle was a significant parameter that influenced the values of the mean tangential velocity and pressure drop. Based on the horizontal inclination angle and the pitch length of the spiral blade distributor, the pressure drop was the most significant parameter that contributed to the reduced energy consumption in the fluidisation system.