06-09-2017, 03:04 PM
The flow between the impeller outlet and the diffuser inlet (ie, in radial separation is generally considered to be complex). With the development of PIV and CFD tools such as mobile mesh techniques, it is now possible to arrive at a prudent solution compatible with the physical nature of the flow. In this paper, the numerical methodology involving the moving mesh technique is used to predict the actual flow behavior, as shown when a target blade of the impeller is caused to move beyond the corresponding vane on the diffuser. Many research work has been carried out using experimental and numerical methods in the interactive impeller-diffuser phenomenon. It has been found in the literature that the effect of the radial separation between the impeller and the diffuser on the interaction and on the performance of the fan has not been the focus of attention. Therefore the numerical analysis is carried out in this work to explore and predict the flow behavior due to the radial gap. This has revealed the presence of optimum radial space that could provide better design characteristics or lower loss coefficient. It is found that there is a better energy conversion by the impeller and an improved energy transformation by the diffuser, which corresponds to the optimum radial space. It was also noted that the overall efficiency increased for a relatively greater separation.
From this literature, it was found that most previous research, especially numerical-based research, had focused on designing or designing state-of-the-art pumps. Few efforts were made to study off-pump performance. Centrifugal pumps are widely used in many applications, so the pumping system may be required to operate over a wide flow range in some special applications. Therefore, knowledge about pump performance outside the design is a must. On the other hand, it was found that few investigators had compared fields of flow and pressure between different types of pumps. Therefore, there is still much work to be done in these fields. A centrifugal pump delivers useful energy to the fluid by pumping largely through velocity changes that occur when this fluid flows through the impeller and the associated fixed pump passageways. It is the conversion of mechanical energy into hydraulic energy from the manipulating fluid to bring it to a place or height required by the centrifugal force of the impeller blade. The input power of the centrifugal pump is the mechanical power and, for example, the electric motor of the drive shaft driven by the primary motor or the small motor.
From this literature, it was found that most previous research, especially numerical-based research, had focused on designing or designing state-of-the-art pumps. Few efforts were made to study off-pump performance. Centrifugal pumps are widely used in many applications, so the pumping system may be required to operate over a wide flow range in some special applications. Therefore, knowledge about pump performance outside the design is a must. On the other hand, it was found that few investigators had compared fields of flow and pressure between different types of pumps. Therefore, there is still much work to be done in these fields. A centrifugal pump delivers useful energy to the fluid by pumping largely through velocity changes that occur when this fluid flows through the impeller and the associated fixed pump passageways. It is the conversion of mechanical energy into hydraulic energy from the manipulating fluid to bring it to a place or height required by the centrifugal force of the impeller blade. The input power of the centrifugal pump is the mechanical power and, for example, the electric motor of the drive shaft driven by the primary motor or the small motor.