Unsteady Flow Structure and Global Variables in a Centrifugal Pump

Abstract

A relationship between the global variables and the dynamic flow structure numerically obtained for a low specific speed centrifugal pump is presented in this paper. A previously developed unsteady flow model is used to correlate the dynamic field with the flow characteristics inside the impeller and volute of a single-stage commercial pump. Actually, the viscous incompressible Navier-Stokes equations are solved within a 3D unsteady flow model. A sliding mesh technique is applied to take into account the impeller-volute interaction. After the numerical model has been successfully compared with the experimental data for the unsteady pressure fluctuations pattern in the volute shroud, a new step is proposed in order to correlate the observed effects with the flow structure inside the pump. In particular, the torque as a function of the relative position of the impeller blades is related to the blades loading, and the secondary flow in the volute is related to the different pressure patterns numerically obtained. Local flow analysis and qualitative study of the helicity in different volute sections is performed. The main goal of the study presented is the successful correlation of local and global parameters for the flow in a centrifugal pump. The pressure forces seem to be the main driven mechanism to establish the flow features both in the impeller and volute, for a wide range of operating conditions.

Unsteady Analysis of Impeller-Volute Interaction in Centrifugal Pump

“…Gonzalez et al [28] also validated the capability of CFD in capturing the dynamics and unsteady flow effects inside a centrifugal pump. In addition, with three dimensional numerical study, Gonzalez and Santolaria [29] able to find a plausible explanation for the flow structures inside the pump that is corresponding with the pressure and torque fluctuating values. Gonzalez et al [30], Spence and Amaral-Teixeira [31] even used three dimensional numerical computation and obtained good agreement between numerical and experimental results for double suction pumps.…”

Numerical Investigation of Pressure Fluctuation in Centrifugal Pump Volute Based on SAS Model and Experimental Validation

“…Numerous studies on unsteady flow have compared experimental and numerical results in centrifugal pumps [4,5]. Generally, the volute of the centrifugal pump is one of the major parts because it is directly connected to the external space.…”

Parametric Study of a Centrifugal Pump Impeller by Varying the Outlet Blade Angle

“…These non uniformities in the velocity distribution are amplified when the pump operates off-design and especially when Q is less than Q N where moreover the aforementioned inlet recirculation establishes. Published research work [14] supports the presence of secondary flow along the duct of the volute, which detected for all impellers and all volume flow rates. Fig.…”

“…The last decade research becomes more sophisticated, specifically recently, Hillewaert et al [11], Gonzalez et al [12][13][14], Byskov et al [15], Meakhail et al [16], Majidi [17] and Feng et al [18] extended the prediction of the performance at various operating conditions, different from the normal one, taking into account the dynamic effects of the flow.…”