Numerical Experiments With Solid Handling Pumps

Solid handling pumps are used in Sewage applications, Slurry transportation, transportation of floating solids etc. Many manufacturers supply such solid handling pumps for different applications. Few of the manufactures have test facility to study the impact of solid particles on overall performance of pump. It is then possible to experimentally bring out effect of solid size, its concentration etc. on overall performance. The literature is available for several such tests conducted by pump manufacturers. In absence of experimental test facility for solid handling pumps, a numerical approach was proposed to investigate the effect of solid particles on the pump performance. Commercially available CFD tool was used to carry out numerical experiments. A standard pump in production was chosen as a test case. It was ensured that experimental test results of similar size pump are available in literature. The work presented here is the extension of the work done by Gupta Amit for a solid handling impeller [8]. The similar impeller assembled with casing for solid handling pump was analyzed first to compute the performance of whole pump with clear water. This was compared with test results available from factory tests conducted experimentally with clear water. The same geometry was then analyzed using particle tracking drag models available in the software given the new boundary conditions of solid additions. Results from the numerical experiments, including effect of particle size, their concentrations etc were brought out. The particle trajectory from impeller entry to exit of casing gave idea as how particles travel in solid handing pumps. The computational results were compared with the ones presented in the Pump Handbook by Karassik. The software results were useful in getting additional information on loss in impeller and casing separately. This gives a clue to as which component needs improvement. The paper describes the approach used in numerical experiments and the results thereof.