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Prospects of digital holographic interferometry in heat transfer measurement
Doleček, R. ; Lédl, Vít ; Kopecký, V. ; Psota, P. ; Václavík, Jan ; Vít, Tomáš
In the measurement of heat transfer problem, a holographic interferometry (HI) is often used mainly because of its unique properties and very high adaptability to different sort of problems under investigation. Although in the area of vibration or deformation measurement of solid body the standard HI is replaced massively by digital holography in the case of refractive index distribution the situation is quite opposite. In this paper we present two different types of digital holographic interferometers. The interferometers with different sensitivities have been build and successfully tested.
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Experimentální mechanika tekutin 2008 - sborník konference
Dančová, Petra ; Vít, Tomáš
The conference will focus on obtaining an overview of projects under investigation, and experimental methods used in the field of fluid mechanics and thermodynamics. Its aim is to organize a network of young research workers who are interested in experimental, and also theoretical, work in the field of fluid mechanics and thermodynamics. The conference should contribute to creating the closer contacts and sharing experience in application of various experimental methods, preparation and implementation of experiments, processing of results and numerical simulations of experiments. Conference proceedings are listed in ISI-Web of Knowledge
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Termoakustický prime mover – demonstrace a prvotní experimenty
Chen, Y.-Ch. ; Vít, Tomáš ; Lédl, V. ; Kordík, Jozef ; Maršík, František ; Wang, A. B. ; Doleček, R. ; Trávníček, Zdeněk
The present paper focuses on an experimental investigation of the thermoacoustic prime mover (sound generator), which was designed with the quarter-wave resonant tube. The working fluid was air under the barometric pressure. This study proves function of the prime mover, and demonstrates variety of experimental methods for experimental investigation of the thermoacoustics: acoustic measurements (the resonant frequency, power spectrum, and sound pressure level), temperature measurement (temperatures along the resonant tube, namely near the thermoacoustic stack), hot-wire measurement (oscillation velocities and displacements), and optical experiments by the holographic interferometry.
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Thermoakustic prime Mover – demonstrace a první experimenty
Chen, Y.-C. ; Vít, T. ; Lédl, Vít ; Kordík, Jozef ; Maršík, František ; Wang, A. B. ; Doleček, R. ; Trávníček, Zdeněk
The present paper focuses on an experimental investigation of the thermoacoustic prime mover (sound generator), which was designed with the quarter-wave resonant tube. The working fluid was air under the barometric pressure. This study proves function of the prime mover, and demonstrates variety of experimental methods for experimental investigation of the thermoacoustics: acoustic measurements (the resonant frequency, power spectrum, and sound pressure level), temperature measurement (temperatures along the resonant tube, namely near the thermoacoustic stack), hot-wire measurement (oscillation velocities and displacements), and optical experiments by the holographic interferometry.
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Piezokeramický generátor pro syntetizovaný proud
Dančová, P. ; Vít, T. ; Trávníček, Zdeněk
Synthetic jets are jets of fluid which are generated by periodic pulzations of fluid. The pulsation generator can work on principle of loudspeaker, piston, pieocrystal or the other equipment. In our experiments, the actuator works on piezoceramic transducer (PTC). The paper shows results of vibrometry principle and results of FEM simulations.
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Syntetizovaný proud
Dančová, P. ; Trávníček, Zdeněk ; Vít, T.
Equipments working on the synthetic jet (SJ) principle can be used in aerospace industry, automotive industry, pumps and ejectors, cooling and heating applications, intensification of mixing in chemical reactors. SJ can be used for jet control and vectoring, flow control in external and internal aerodynamics, intensification of heat transfer. The main advantage of these applications is relative simplicity of SJ equipment. This article summarizes primary SJ world studies, and it shows examples of own experimental results.
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Analysis of the synthetic jet at the actuator output
Kordík, J. ; Šafařík, P. ; Vít, T. ; Trávníček, Zdeněk
The paper focuses on a pulsatile axisymmetric flow in an outlet orifice of a zero-net-mass-flux actuator of a synthetic air jet. A simplified task (pulsatile pipe flow) is studied theoretically. Velocity profiles have been measured using hot-wire anemometry; the approximation of the experimental data is based on the theoretical solution. The results improve our knowledge of synthetic jets and provide data for their advanced numerical simulation.The paper focuses on a pulsatile axisymmetric flow in an outlet orifice of a zero-net-mass-flux actuator of a synthetic air jet. A simplified task (pulsatile pipe flow) is studied theoretically. Velocity profiles have been measured using hot-wire anemometry; the approximation of the experimental data is based on the theoretical solution. The results improve our knowledge of synthetic jets and provide data for their advanced numerical simulation.
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Numerická simulace a vizualizace vytváření syntetizovaného proudu
Trávníček, Zdeněk ; Vogel, Jiří ; Vít, T.
The paper presents the results of numerical and experimental investigations of a synthetic jet generation. The experiments were performed in air by means of flow visualization and hot-wire anemometry. The subsequent numerical simulation was performed using the commercial code FLUENT. The geometry, boundary conditions, and material properties of the numerical simulation were defined according to the real experimental situation.
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Syntetizovaný proud - návrh generátoru a ověření jeho funkce
Trávníček, Zdeněk ; Vít, T. ; de Boer, P. ; Maršík, František
A zero-net-mass-flux actuator was designed, and a synthesis of an air jet was investigated. The operating parameters were suggested near the resonance frequency. The proper actuation was experimentally tested by smoke visualization and hot-wire anemometry. Two typical synthetic jets are presented, namely the so-called "long" and "short" extruded fluid column cases. The maxima of the centerline local and the time-mean velocities reached approximately 27 m/s and 8.7 m/s, respectively.
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