الفهرس 
Pervious workOnly 14 pages are availabe for public view
 |  | from | 211 |  |  |
| | | from | 211 | | |
Abstract
The objective of this investigation is to present a theoretical model to predict the cavitation erosion distribution under multiphase flow in centrifugal slurry pump impeller, and then to check experimentally the validity of the model concerning running speed, pressure distribution, concentration distribution, void fraction and erosion rate. The theoretical model based on energy analysis is proposed to predict the material weight loss due to wear erosion and cavitation erosion. An energy concept for bubbly collapse is used in developing this model. The experimental test rig was built in order to test the obtained numerical results. The test loop is equipped with a centrifugal pump having eight blades cast iron impeller, vacuum pump and vibration meter. The effect of vibration on the centrifugal pump can be obtained experimentally in the case of two and three phases flow. The flow behavior of the peptised slurries by addition of sodium carbonate will be discusse to study the effect of changing the physical/ chemical environment of slurries on the centrifugal pump performance. The experimental test rig of the centrifugal pump used for testing two volumetric concentrations of sand slurries (C= 5% and 10 %) of constant peptising agent (sodium carbonate) with mass ratio of (ca=0.5%) to the mixture flow. The results show that the centrifugal pump performance is improved and the cumulative weight loss depth of penetration are reduced due to peptisation. The obtained theoretical results show good agreement with the experimental results obtained in this investigation. The results show that the erosion, pressure and void fraction is not uniform. it also indicated that the increasing of vibration level is associated with decreasing the flow rate. The weight loss rate increasing rapidly with impeller speed. The results of this investigation clarify the basic wear mechanism and erosion rate in pump designed for handling vapour solid-liquid bubbly flow. It allows also to predict the high wear regions of pump impellers, which will help the design engineer in improving the pump hydraulic design in order to minimize wear.