الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
Design of double volute centrifugal pumps is very sensitive to the radial gap between the rotor (impeller) and stator (volute). The previous experimental work which was done by ([3], [4], [5], [6], [16]) showed that the main sources of the high vibrations and noise of that pump are the bad design of the radial gap and the high rotor-stator interaction.
The current research work shows 3D numerical studies on a double volute centrifugal pump. These studies help in investigating the effect of changing the value of the radial gap on the static pressure distribution, unsteady pressure fluctuations, energy of pulsations, and pump performance at different flow rates and locations inside the pump. According to [16], the models that were used for the experimental investigation rotates at 3540 rpm which delivers 12 L/s of water at the design conditions. The same geometry of the those models are used for the current 3D simulations using the same boundary conditions that were published by Khalifa [16]. The 3D numerical modeling was carried out by ANSYS FLUENT 15 commercial package. The static pressure values were recorded at six locations around the impeller using the same coordinates that were used by Khalifa [16] to study the accuracy of the 3D simulations and then calculate the other numerical quantities that were mentioned before. The main flow rates that were used for the investigation are (Qn, 0.75Qn, 0.5Qn, and 0.25Qn).
Generally, the 3D results gave a good agreement with the experimental results that were published in ([4], [5], [16]). However, the pressure fluctuations at 0.25Qn were over-estimated. Also it was found that increasing the gap between the rotor and stator decreases the pressure fluctuations and the energy of pulsations inside the pump as a result of decreasing the interaction between them. Also, it was found that the performance of the pump was not significantly affected.