In connection with the increasing requirements for cleanliness in conticast steel, it is necessary to develop original solutions. The tundish, as the last refractory-lined reactor, gives enough space to remove inclusions by optimizing the flow of steel. The basic component of the tundish is the impact pad, the shape of which creates a suitable flow of steel, thus making it part of the tundish metallurgy. The optimal steel flow in the tundish must avoid creating dead zone areas, or the slag “eye” phenomenon in the slag layer around the ladle shroud, and is intended to create conditions for the release of inclusions by promoting reactions at the steel-slag phase interface. The flow also has to prevent excessive erosion of the tundish refractory lining. This paper compares the standard impact pad with the “Spheric” spherical impact pad using computional fluid dynamiscs (CFD) tools and physical modelling. The evaluation criteria are residence time and flow in the tundish at three different casting speeds.
Vortex ring state, or settling with power condition, of tail rotor of helicopter Mi-17 is investigated by numerical methods of Computational Fluid Dynamics (CFD). Distinct shape of inflow-thrust curves is described and various flow patterns at different locations of the curve are identified. The shape of the curve is identified as a feature responsible for uncontrolled rotation of helicopter at the onset of vortex ring state at the tail rotor.
Improvement of flow quality in the test section of wind-tunnel with two configurations of screens is evaluated, using two methods - by the measurement of aerodynamic drag of sphere and by the hot-wire CTA measurement of turbulent fluctuations. Only configuration with the screen in settling chamber improves the quality of the flow.
Single rotor vertical take-off and landing (VTOL) unmanned aerial vehicle (UAV) is described. Severaldifferences in comparison to multirotor UAV have to be solved to handle succesfull flight. Geometry, acting forces and moments are investigated with goal to keep stable hovering. Stabilization system is recommended for freeing operators attention to the main flight task.
Known types of airbrakes (also known as a dive brakes or spoilers) of sailplanes are described along with certification requirements. Documented failures are analyzed and divided to categories. Numerical modelling is used to show the stress and deformation applied on airbrakes during the maximum load on L-13 Blanik sailplane.