Effects of Innovative Suction Slots on the Performance of a Radial Bladed Impeller of a Centrifugal Blower - A Numerical Transient Analysis

Abstract

The recirculation zones present in between the blade passages give rise to some losses in centrifugal blowers. The main objective of this study is to realign the flow at the suction side of the impeller by weakening the recirculation zones. This can be achieved by providing slots on the impeller blade geometry, which will efflux the flow from the pressure side of the impeller towards its suction side. Effects of single and multiple slots were analysed numerically for possible pressure recovery. The comparison of performance among various slot configurations is represented in terms of non-dimensional parameters. It is found from numerical study that a single slot provided at a radial distance of 75% from blade root and twin slots located at 50 % and 75% from the leading edge of the impeller vane significantly contribute to the static pressure recovery across the fan. Hence, it is beneficial to use multiple suction slots for better performance augmentation.