SIMULATION OF NON-OVERLOAD CHARACTERISTICS OF SERIAL-PARALLEL CENTRIFUGAL PUMPS.

Serial-parallel centrifugal pumps (SPCPs) are a new type of pump with two working conditions: high head with low flow and low head with high flow. However, the motor of SPCPs is easily burned because of its various operating conditions. To clarify the effect of the flow field on the non-overload characteristics of SPCPs, revealing the non-uniformity of the flow distribution is necessary. This study derived the velocity triangle theory of the pump, and a numerical simulation by 3D models was conducted to investigate the internal flow patterns of SPCPs. The magnitude of the flow deviation angle at different cross-sections was calculated to evaluate the non-overload characteristics under different operating conditions. The results showed that the formula of the maximum shaft power and the local flow rate were two important parameters of the non-overload interpretation of the pump. The simulated results were in good agreement with the experimental results at the designed flow rate. In addition, the flow deviation angle under the serial operating condition, which was more likely to achieve the non-overload characteristics, was evidently higher than that under the parallel operating condition. The conclusions solved the issue on the theoretical design of the non-overload characteristics considered in a non-uniform flow in SPCPs. [ABSTRACT FROM AUTHOR]