Numerical study on the mechanism of fluid energy transfer in an axial flow pump impeller under the rotating coordinate system

Abstract

It is a necessary condition to obtain the fluid movement law and energy transfer and loss mechanism in the impeller of the axial pump for achieving an efficient and accurate design of the axial flow pump. Based on the shear stress transport k-ω turbulence model, a three-dimensional unsteady numerical simulation of the whole flow field of an axial flow pump was presented at different flow rates. Combined with the Bernoulli equation of relative motion, the flow field structure in the impeller under design condition was studied quantitatively in the rotating coordinate system. The fluid movement law and energy transfer and loss mechanism in the impeller of the axial flow pump was described in detail. In the relative coordinate system, the mechanical energy of the fluid on the same flow surface conserves. The dynamic energy is continuously transformed into pressure energy from the leading edge to the trailing edge and the dynamic energy is continuously transformed into pressure energy from the leading edge to the trailing edge. The energy conversion is mainly completed in the front half of the blade. The friction loss and the mixing loss are the basic sources of losses in the impeller flow passage. Most hydraulic losses of impeller flow passage are caused by friction and the hydraulic losses near the trailing edge are dominated by mixing loss. This research has certain reference significance for further understanding the flow field structure in the impeller of the axial flow pump, improving its design theory and method, and then realizing its efficient and accurate design of the axial flow pump.