Centrifugal pumps play a crucial role in industrial operations involving fluid transport. The quest for optimizing efficiency and reducing energy usage is a driving force behind research into their performance. The literature continues to offer opportunities for the creation of models that accurately depict the head generated by pumps, with a particular focus on impellers. The current pumps, however, are still far from being completely optimized. The idea of this paper is to conduct an analysis of energy losses and propose a mathematical expression to represent the head produced by a radial impeller, P23 model, working with water flow, considering that head is influenced by losses due to recirculation, shock/incidence, internal friction. The head losses are quantitatively evaluated from experimental data acquired via particle image velocimetry, which provides information on velocity vector direction and wall shear stress, both useful for the analysis. Our results reveal that the loss due to friction is the most significant, accounting for 40–90% of the total head loss, while shock and recirculation losses are restricted to 35% and 25%, respectively. Friction factors vary from 1.0 to 26 depending on the flow rate, as a result of wall shear stresses reaching up to 430 N/m2, mainly influenced by pressure and pseudoforces. The head calculated through the new proposed expression is finally compared with the actual head generated by the impeller, measured via experiments dedicated to assess the pump performance. According to our results, the relative deviations between the calculated and measured heads are limited to 5%. Although our results have been validated for a single P23 impeller geometry, the methodology developed here can be extended to other impellers in the future. The results may thus represent a step forward for designing more efficient and power-saving pumps.
Tag: Energy losses
Experimental Investigation on Velocity Fields, Vorticity, and Turbulence within the Stage of an Electrical Submersible Pump (ESP)
This paper presents an experimental study on the flow dynamics within an Electrical Submersible Pump (ESP) stage. An ESP prototype with transparent impeller and diffuser was designed and manufactured to allow flow visualization, which was achieved by using a Time-Resolved Particle Image Velocimetry (TR-PIV) system. Single-phase water flow tests were conducted in various flow rates corresponding to percentages of the Best Efficiency Point (BEP). The average velocity fields, vorticity contours, and turbulent kinetic energy values obtained in the whole impeller reveal that the flow behaviour is very dependent on the ESP operational condition. Energy losses due to turbulence are lower when the pump works at the BEP. But when the device operates at off-design conditions, the flow becomes complex, with high vorticity and turbulence which cause a reduction in the performance. This type of investigation may be useful to validate numerical simulations, support the proposition of mathematical models, or help create improved impeller designs.