It has been recognised that some of the vital characteristics such as flow patterns and pressure fluctuations of the centrifugal pump will affect the overall pump efficiency. However, most of past research based on theoretical analysis or experiments, which are time consuming and expensive. With the development of computer science, it is possible now to investigate the three dimensional unsteady flow patterns in the centrifugal pump. Then the study can be applied to establish the correlation between the pump characteristics and efficiency numerically. This thesis describes some experiments which establish the performance curve of a particular commercial centrifugal pump, which then be used as the basic data for the numerical results to be compared with. The modal test of this centrifugal pump was conducted for both its components and assembly to verify the structural rigid assumption in the numerical simulation. Both static numerical method (Frozen Rotor) and transient numerical method (Sliding Mesh) were used in this thesis. The key findings are summarized as follows: From the results obtained by Frozen Rotor method, it can be seen that the general trend of global properties including water head and pump efficiency were captured well while there existed some differences when compared them with experimental data. This was possibly due to the limitations of Frozen Rotor method to predict unsteady flow phenomenon. When the Sliding Mesh method applied, the results indicate that: First of all, it was possible that the position of the large vorticity zone could be a factor which would result in the change of the pump efficiency. Secondly, if the helical region distributed uniformly, the pump is more likely to operate at BEP. On the other hand, the pump efficiency would drop if non-uniform helical regions observed.
|Publication status||Unpublished - 2012|