Recirculation power in the balance of hydraulic losses of centrifugal pump

Abstract

Purpose. Improving the methodology for determining the recirculation power of low and medium specific speed centrifugal pumps in order to determine ways to increase their energy efficiency. Methodology. A numerical simulation based on the physical nature of the phenomena of recirculation power, conducted using the ANSYS CFX software. findings. The dynamics of changes in the integral parameters of the operational process of a centrifugal pump D2000­100­2 at flow rates that deviate from optimal (Qopt) are investigated and presented. Based on the results of the numerical simulation, the values of the theoretical head of the impeller, as well as the head at its outlet, taking into account and excluding recirculation, are determined. Due to the difference in the obtained head values, the value of the power losses for recirculation and their part in the balance of hydraulic losses are determined. Based on the simulation results of the operational process of the centrifugal pump D2000­100­2, it is shown that part of the recirculation losses in the flow rate range (0.7–0.4)·Qopt is 25–30 % of the total hydraulic losses, while in the flow rate range (0.3–0.1)·Qopt it increases to 44 %. originality. Further development of the method for determining the recirculation power which is based on the results of numerical simulation of three­dimensional fluid flow in the flowing part of the centrifugal pump, taking into account the circulation vortex processes at the outlet of the impeller. Practical value. Definition of the recirculation power in the power balance of hydraulic losses at the pump design stage. Taking account of the influence of the design parameters of the impeller on the value of recirculation.