Performances and Flow Analysis in the Centrifugal Vortex Pump

Abstract

Improvements to the characteristics of a centrifugal pump through the addition of a vortex rotor were investigated both experimentally and with computational fluid dynamic (CFD) analysis. The idea behind that improvement is in creating so-called coherent structures of eddies and turbulence in the peripheral area of the vortex rotor mounted at the back side of centrifugal rotor. Research on the energy transformations in the centrifugal vortex pump in this work was carried out using numerical simulations of the flow in the centrifugal and the centrifugal vortex pump. Measurements of relevant parameters that describe the performance of pumps, at their physical models, were gained from experiments. The measurement results were used as experimental validation of numerical simulations. In contrast, flow visualization derived from the numerical simulation was used to interpret measurements. In deriving the experimental procedure, special care was taken with the flow measurements. The reason for this is in the fact that the flow measurements had the biggest influence on the overall measurement uncertainty. However, flow measurements were the most demanding with regards to the experiment design and in taking the measurement readings. This experimental-CFD research made it possible to undertake an assessment of vortex rotor contribution on the head of the centrifugal vortex pump. The influence of the vortex rotor on the efficiency of the centrifugal vortex pump was investigated by comparing it with the efficiency of the centrifugal pump with the same geometry. An analysis of the flow structure was conducted in order to better understand the energy transformations that are the result of the interaction between the flow from the channels of the centrifugal part of the centrifugal vortex rotor and vortices formed at the vortex part of the centrifugal vortex rotor as well as their interactions with the stator. It was shown that this additional energy significantly increases pump head while increasing pump stability. This synergetic work has demonstrated that while vortex rotor gives additional energy to the fluid particles, that did not enter stator due to the energy lack by changing their momentum; at the same time, some of the kinetic energy contained in the vortex rotor induced vortices is also added to those fluid particles.