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Design and realization of an aerodynamic tunnel for spraying nozzles
Cejpek, Ondřej ; Jaroš, Michal (oponent) ; Jedelský, Jan (vedoucí práce)
Working conditions of atomizers in engineering applications differ from those in laboratory, where the atomizers are tested. The usage of a wind tunnel can simulate more realistic conditions. The wind tunnel is used to investigate the atomizers in cross and co-flowing air stream. The investigation of a spray in the wind tunnel can bring an insight into the spray behaviour in cross and co-flow. The present master thesis deals with a design of a small-scale, low-speed wind tunnel for the experiments with sprays created by the pressure swirl atomizer with spill-line in cross and co-flow conditions. Many wind tunnel designs were proposed; however, the most suitable wind tunnel design for spray study is an open type wind tunnel in blow down arrangement with closed test section. The wind tunnel is composed of several sections and components; each component is designed to obtain a good flow quality in the test section. The spray is investigated by using Phase Doppler anemometry (PDA), Laser Doppler anemometry (LDA), Particle image velocimetry (PIV), and by high–speed imaging. These optical techniques pose particular design requirements on the wind tunnel. A design procedure of small-scale, low-speed wind tunnel is described, and the flow quality in the test section is verified. Velocity of the flow in the test section is in the range from 0 m/s to 40 m/s with turbulent intensity below 0.7%. In the chapter 7, high–speed visualization of a spray in cross-flow is presented. The flowing air changes the breakup length, cone angle, and spray shape. The smallest droplets are carried away by the flow.
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