Design and Fabrication of Centrifugal Blower using Locally Sourced Materials

Abstract

This paper deals with the design and fabrication of a centrifugal blower. A backwards-curved blower was employed in the study, because the backwards-inclined blower is highly efficient, operates at approximately twice the speed of a forward-curved air blower, and is suitable for high-state pressure applications. The design consideration and analysis concerned within this study is for a single-stage centrifugal blower with capacity, Q (0.317m³/min) at a pressure, P (10,000Pa), head, H (61.87m), and shaft speed, N (1450rpm). The lowest air volumetric rate of 0.073 m³s^-1 was obtained at closing the inlet (85%), the impeller speed (400rpm), and the air volumetric rate (0m³s^-1) at closing the inlet (100%) for all the impeller speeds. The highest air volumetric (0.379m³s^-1) was obtained at closing the inlet (0%) and impeller speed (960rpm). The impeller speed of 400rpm with a static pressure value of 47.03Pa, can be computed as the pressure value at 960rpm (i.e., 40.07Pa), indicating a 17% deviation (difference of 6.96 Pa). The highest total efficiency achieved is on closing the inlet of 50% and the impeller speed of 960rpm was attained at about 9.93%, whereas the lowest total efficiency on all the impeller speeds is achieved at the closing inlet of 0%. The result shows that the centrifugal blower was efficient over a wide range of flows. The blower provides a small unit of footprints with a good turn-down capacity.