Centrifugal blower volute optimization based on Taguchi method

Abstract

The performance of centrifugal blower is enhanced with an optimization process on the blower volute using Taguchi method and ANOVA approach. The important geometrical parameters of volute are prioritized by applying first level of analytic hierarchy process. The analytic hierarchy process (AHP) is a structured technique for organizing and analyzing complex decisions, based on mathematics and psychology. Based on review of literatures, three levels are defined for each geometrical parameter. Reduction in the percentage variation of static pressure at impeller outlet, minimization of losses inside volute and maximization of stagnation pressure at volute outlet are selected as quality characteristics to ensure the enhancement of centrifugal blower performance. In this process, numerical simulation of 3-D flow in single stage centrifugal blower volute is carried out by FLUENT software for matrix experiments. These matrix experiments are suggested by Minitab software. The simulation case is carried out by flow, turbulence and Energy equations using SIMPLE pressure–velocity coupling. Standard discretisation method is used to solve pressure whereas; others are solved by second order upwind discretisation method. The realizable k–ε is adapted as turbulence model. Stator–rotor interactions are defined by means of mixing plane model of multiple rotating reference frames. Impeller is situated in rotating reference frame whereas; volute is in fixed reference frame. The process reveals that optimization of the original geometry of blower, at 1.5 times width of impeller, 24° tongue angle and 10% reduction in volute outer radial locations, pressure head and flow uniformity increases compared to other cases; this improvement takes place due to reduction in the non-uniformity of flow at impeller outlet and losses inside the volute passages. The experimental performance of optimized configuration is carried out and compared with existing centrifugal blower. The result indicates better performance in case of optimized volute than original configuration of volute. In case of optimized centrifugal blower, 7.4% higher efficiency is observed at the design rated speed compared to existing centrifugal blower.