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The Effect of Blade Overlap on Aeroelastic Coupling
Procházka, Pavel P. ; Uruba, Václav ; Pešek, Luděk ; Bula, Vítězslav
This experimental study was established to clarify an aeroelastic coupling in the case of rotational periodic bodies. The blade grid was placed behind the outlet of the blow-down wind tunnel. Three of five blades were constructed to allow vertical position changing by the effect of three shakers. Particle Image Velocimetry was used to measure mean-phase velocity and dynamical parameters of the flow. The effect\nof blade enlargement will be introduced as well as the difference between forward and backward wave propagation.
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Technique for Determination of Phase Changes in Moist Air Flowin a Blade Cascade
Vestfálová, M. ; Šafařík, P. ; Šimurda, David
The paper deals with theoretical and numerical tool for prediction of phase changes in moist air flow in flow systems. Partially solidified or liquidized steam in moist air appears to be a problem for peration wind tunnels, turbomachines, etc. Determination of phase change conditions is based on thermodynamic theory. Parameters of saturated homogeneous moist air are solved when expansion process is simulated at calculations. Conditions of saturation are successively verified and finally determined. Special phase diagram for moist air is designed.
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Design of low-subsonic blade cascade model for aero-structural dynamic testing
Pešek, Luděk ; Hála, Jindřich ; Šulc, Petr ; Chládek, Štěpán ; Bula, Vítězslav ; Uruba, Václav ; Cibulka, Jan
Low-subsonic blade cascade model for aerodynamic testing was design in the Institute. The aim is to study the flow dynamics and flutter phenomenon in the cascade with moving blade profiles. The numerical calculations of two proposed cascades were performed for analysis of influence of stagger angle, incident angle of flow and inter-blade phase angles of the relative movement of blades. The results of numerical simulations of fluid dynamics of non-stationary flow both as viscid and non-viscid are presented. Futhermore the solution of the physical model of the designed cascade including excitation of profiles, measuring of the profile displacement and aerodynamic forces are described.
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Modelling of running waves in turbine blades cascade
Půst, Ladislav ; Pešek, Luděk
Dynamic properties of blades in the blade cascade excited by steam flow from the stationary bladed disk are investigated with the aim to explain origin and behaviour of running waves. It is shown that one of the most important reasons for existence of running waves is the running periodic forces from steam wakes due to different numbers of blades of stationary and rotating wheels. On a simplified computational model of disk with closed 10-blades bundle are presented resulting velocities, theirs directions and modes of forced running waves. The effect of these forced running waves on the existence of flutter waves will be shortly mentioned as well.
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Gas turbines
Bukáček, Miroslav ; Kracík, Petr (referee) ; Pospíšil, Jiří (advisor)
The aim of this Bachelor thesis is create a summary of gas turbines and their comparison with internal combustion piston engines. This thesis deals with work cycles of gas turbines, internal combustion piston engines and their effectiveness. It contains a description of the basic components necessary for the operation of gas turbines. In conclusion is comparing of gas turbines and internal combustion piston engine.
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CFD Calculations in Turbomachinery and their Validation
Váchová, J. ; Louda, P. ; Příhoda, Jaromír ; Luxa, Martin ; Šimurda, David
Numerical data obtained by 2D compressible flow CFD simulation were validated by the comparison with experimental results. The investigation was made on the mid-section of the 48" long rotor blade and it was focused on the effect of shock-wave interactions with shear layers. This interaction results in the laminar/turbulent transition where separated flow occurs and it has impacts on flow structure and the blade cascade losses. Numerical simulations were carried out by two different codes: the commercial code NUMECA based on the gamma-Re transition model connected with the SST k-epsilon/k-omega turbulence model and in-house code of the Dept. of Technical mathematics, CTU Prague/ Institute of Thermodynamics in Prague. Simulations of the laminar and the fully turbulent flows were accomplished for comparison using the same numerical approach.
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