Vortex pumps are widely used in wide range of hydro-transportation applications. Main disadvantage of this type of pump design is low efficiency. Despite ongoing effort to improve vortex impeller performance precise algorithm for their optimal design doesn't exist. One of the ideas is to use winglets (super-vortex) on the tip of the impeller blades. Conducted literature studies have shown that there is not yet clarified principle of winglet design. Authors have performed numerical simulations and measurements for three different arrangements of winglets with varying impeller coverages. From the obtained results recommendation for optimal winglet placement is deducted.

This work focuses on methods of submersible sewage mixer performance evaluation comparison. In the paper an experiment with a submersible mixer with a published and known geometry has been presented. The authors measured thrust, torque rotation speed and electric power. Experiment was compared with results obtained with a steady state numerical simulation. Next CFD results were checked with a theoretical approach for the mixing range. Both theoretical and numerical methods showed good applicability for the industry.

This paper presents a two-dimensional implementation of the high-order penalized vortex in cell method applied to solve the flow past an airfoil with a vortex trapping cavity operating under moderate Reynolds number. The purpose of this article is to investigate the fundamentals of the vortex trapping cavity. The first part of the paper treats with the numerical implementation of the method and high-order schemes incorporated into the algorithm. Poisson, stream-velocity, advection, and diffusion equations were solved. The derivation, finite difference formulation, Lagrangian particle remeshing procedure, and accuracy tests were shown. Flow past complex geometries was possible through the penalization method. A procedure description for preparing geometry data was included. The entire methodology was tested with flow past impulsively started cylinder for three Reynolds numbers: 550, 3000, 9500. Drag coefficient, streamlines, and vorticity contours were checked against results obtained by other authors. Afterwards, simulations and experimental results are presented for a standard airfoil and those equipped with a trapping vortex cavity. Airfoil with an optimized cavity shape was tested under three angles of attack: 3°, 6°, 9°. The Reynolds number is equal to Re = 2 × 104. Apart from performing flow analysis, drag and lift coefficients for different shapes were measured to assess the effect of vortex trapping cavity on aerodynamic performance. Flow patterns were compared against ultraviolet dye visualizations obtained from the water tunnel experiment.