Investigation of Flow of Centrifugal Slurry Pump Handling Bottom Ash and Fly Ash Mixture

Abstract

Centrifugal pumps are used for transportation of solids and liquid over short to medium distance through the pipelines. A centrifugal pump designed to handle the liquids is normally single stage, end suction type having radial or mixed flow configuration of blades. Centrifugal pump of radial-flow type is mostly used in slurry service. A conventional centrifugal pump is designed to handle bottom fly ash mixture liquids. The modifications incorporated in the pump include enlargement of flow passages to accommodate bigger solid particles, robust impeller with smaller number of vanes, special seals and proper material of construction to ensure longer life. These have to be operated with relatively wide clearance at impeller-casing contacts to minimize choking and localized wear. These modifications increase the hydraulic losses in the pump and deteriorate the pump performance. The present study is concerned with the evaluation of the performance characteristics of a centrifugal slurry pump when handling bottom fly ash at 30% concentration of bottom fly ash slurry at different speeds1000, 1150, 1300 and 1450 rpm. From the experimental evolution it is concluded that the parameters defined for head and capacity of the conventional pumps are also applicable for the slurry pumps with water despite the constructional differences. From the bottom ash characteristics it is also observed that addition of the fly ash in the bottom ash developed head decreases with increases of the flow rate results decreases the power consumptions of the transportation of the bottom ash in pipelines.