University of Twente Student Theses


Visualization and pressure measurements of the oscillatory flow in a jet pump

Dixhoorn, Frederieke van (2014) Visualization and pressure measurements of the oscillatory flow in a jet pump.

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Abstract:In closed-loop thermoacoustic engines a time-averaged mass flux known as Gedeon streaming can exist [18]. This Gedeon streaming results in a heat leak that causes the efficiency of the engine to decrease. A narrowed, tapered tube section, known as a jet pump, can suppress this time-averaged mass flux. By taking advantage of asymmetry in hydrodynamic end effects a pressure drop can be imposed across the jet pump [18]. In this bachelor's assignment a jet pump is designed with a geometry chosen in order to impose such a pressure drop. For experimentation with this jet pump a test section is introduced within an experimental set-up consisting of a loudspeaker, a cone, and a resonator tube. This experimental set-up is used at the University of Twente for research in thermoacoustics. Two different sets of experiments are performed with the jet pump section: pressure measurements and flow visualization experiments. The results of the pressure measurements are analyzed and compared with an analytical model as well as a simulated model. The models show a clear match with the experimental results; however, this remains only an initial estimation. To obtain qualitative images of the flow field of the acoustic wave at several instances in time the existing technique of smoke flow visualization [20] is extended and optimized. The main features which are altered are the camera triggering and the method of smoke injection. Various images are captured at a range of pressure amplitudes displaying clear flow patterns. However, the technique of smoke flow visualization remains problematic and a clear image of the flow field of one period of the acoustic wave was not obtained.
Item Type:Essay (Bachelor)
Faculty:TNW: Science and Technology
Subject:50 technical science in general
Programme:Advanced Technology BSc (50002)
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