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Aerodynamics tests of a transonic turbine blade cascade model consisting of low number of blades
Šimurda, David ; Luxa, Martin ; Šafařík, Pavel ; Synáč, J.
Contribution is concerned with experimental investigation of the transonic turbine blade cascade aerodynamic characteristics. Due to specific geometry of the blade cascade, the blade cascade model consists of six blades only. Therefore, special experimental setup is adopted and its influence on the resultant blade cascade aerodynamic characteristics is discussed. Experimental data are obtained applying both optical (interferometry, schlieren technique) and pneumatic methods (mainly traversing with a five-hole conical probe). Special attention is paid to flow structures, which significantly contribute to the increase of kinetic energy loss coefficient. Results of current investigation are compared to former results obtained at usual experimental set-up.
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Annular Jets and Annular Impinging Jets
Turek, Tomáš ; Trávníček, Zdeněk ; Šafařík, Pavel ; Tesař, Václav
A near field of annular jets and annular impinging jets is experimentally investigated at three inner/outer diameter ratios 0.84, 0.90 and 0.95. Time-mean velocity profiles are evaluated, and three main flow field zones are distinguished – in agreement with the literature, namely the initial merging zone, the intermediate one, and the fully merged one. A distribution of the pressure on the impingement wall is measured for various nozzle-to-wall distances. Two basic annular impinging jet regimes are clearly distinguished, with either small or large recirculation bubbles. Moreover, a hysteretic behavior has been identified under specific parameters.
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Visualization of synthetic jets at higher stokes numbers
Broučková, Zuzana ; Trávníček, Zdeněk ; Šafařík, Pavel
Visualization of synthetic jets at higher Stokes numbers (S = 90 and 127) by the phase-locked smoke-wire technique is presented and discussed. The working fluid is air. The Reynolds numbers are quantified using hot-wire anemometry. Although our method of visualization essentially provides only qualitative results, the present study also demonstrates some quantitative results, namely the behavior of the zero-net-mass-flux jet near its critical stage. Visualization of the sub-critical stage is also shown.
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The interaction of continual and synthetic jets
Broučková, Zuzana ; Trávníček, Zdeněk ; Šafařík, Pavel
This work deals with an interaction of continual and cross synthetic jets. Both jets are axisymmetric. All measurements have been performed in air by means of the Pitot tube and hot-wire anemometry. Flow visualization has been also performed. The possibility of flow control is shown and quantified. For the moderate momentum ratio, the mean jet deflection reasonably agrees with the momentum conservation.
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