Torque flow pumps are widely used for pumping of fluids with high content of solid and fibrous inclusions and gas bubbles, in particular, for pumping of sewage and wastes. Fluid flow in these pumps is featured with strong vortex patterns, making it difficult to predict reliably their performance curves numerically. The paper is devoted to selection of a numerical approach for simulation of fluid flow in a torque flow pump of “Turo” type and its influence on simulation results. In particular, influence of geometrical configuration of the rotor-stator interface as well as numerical grid fineness is demonstrated. For one geometric configuration, the fluid flow is simulated with different turbulent models, with a steady state as well as transient approach. The simulations were performed using the software product ANSYS CFX. The simulation results are compared with the experimental measurements in the torque flow pump of “Turo” type. The experimental research included probing of fluid flow in three cross-sections of the stator domain, visualizing of streamlines along the rotating and stationary walls, as well as obtaining of performance curves. A good agreement between the numerical and experimental results is obtained as the rotor-stator interface is located at some distance off the rotating parts. Influence of choice of the turbulence model on the simulation results is demonstrated. Conclusions and recommendations are made concerning the choice of initial and boundary conditions, geometrical configuration of the rotor-stator interface, and parameters of turbulence models that affect both the flow pattern in the pump and its performance curves as well as the numerical solution time and required computational resources.

The article is devoted to the research of the torque-flow pump operating process. Its work is closely connected to the formation and stable functioning of the toroidal vortex. The theoretical bases of the formation of a toroidal vortex and the process of energy transfer in a torque-flow pump are considered in the research (vane and vortex components of the operating process). The fact of the presence of some additional hydraulic losses due to the mismatch of the location of the toroidal vortex center and the impeller blade edges has been established. The urgency of the paper is increasing the efficiency of torque-flow pump by improving its flowing part. The upgrade of the pump consists of the theoretical justification and practical implementation of the reduction of these additional hydraulic losses. In this aspect, the location of the impeller blade edge is aligned with the toroidal vortex center. The research was performed by conducting a numerical investigation. The calculations of a high specific speed torque-flow pump of three different design configurations of the impeller blades were performed. Practically confirmed increasing of the head (by 3.2 m) and efficiency (by 7-8%) of the pump with the second design of the impeller blades.

No abstract

Due to a simple design and hydraulic passage that is the least susceptible to clogging, torque flow pumps (TFP) of Turo type are the most common pumps used for pumping various hydraulic mixtures. These pumps are referred to vortex pumps, operation of which is accompanied by energy loss and vortex formation resulting in low economic efficiency. Since the TFP is a vortex hydraulic machine, the ratio of the fluid velocity in the free pump passage to the impeller rotational speed ωfluid /ω is an indicator of the TFP efficiency. The higher the value of ωfluid , the more efficient the pump is. The mechanism of the energy transfer in the TFP is caused by both blade and vortex operating process, or a combined operating process. The efficiency of the pump can be improved by increasing the portion of blade operating process. The aim of the study is to improve the efficiency of the TFP of Turo type by modifying the impeller design, to obtain a basic equation of the TFP with a new impeller which has several extended blades, and to study the influence of the impeller geometry on the pump performance experimentally. The study was carried out by analytical and experimental methods. The equation describing the head dependence on the hydraulic passage dimensions of the pump with a new impeller was obtained analytically. This equation can be used to clarify the methodological recommendations for designing the pump. The energy balance in the TFP was analyzed. During the testing on a test rig, the characteristics of the pump were obtained, which confirmed the advantages of using the modified impeller with extended blades resulting in increase of the portion of the blade operating process.