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Numerical Investigation of Jet Pump Performance in Traveling Wave Thermoacoustic Engine

Barzegari, Ali | 2017

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50170 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Ghorbanian, Kaveh
  7. Abstract:
  8. Thermoacoustic engines are a promising alternative to the conventional heat engines due to the absence of moving parts in the hot region and the small temperature difference required for operation. However, the traveling wave thermoacoustic engine configuration has a relatively lower efficiency due to a phenomenon called Gedeon streaming. In this regard, a jet pump might be used to lower the negative effects of Gedeon streaming. The jet pump, which is simply an element consisting of one or more tapered holes, induces an oscillating flow through the asymmetric device and hence resulting in a time-averaged pressure drop across it. As a result, by balancing this time averaged pressure drop with that from the regenerator of the thermoacoustic engine, Gedeon streaming can be suppressed. In this research, first, a numerical parametric study is performed on the geometrical variables of the jet pump in terms of the mean pressure difference and acoustic power dissipation. Next, by incorporating the obtained results, a model is developed to predict the mean pressure difference of the jet pump as a function of the geometrical variables. Further, considering the physical limitation of the operating thermoacoustic engine, an optimal geometry is determined which satisfies a desired mean pressure gradient as well as the minimum acoustic power to suppress the Gedeon streaming. In addition, a sensitivity analysis is performed on the jet pump performance envelope. The results indicate that if the required mean pressure difference is not provided by the jet pump, then the efficiency of the thermoacoustic engine decreases drastically. Finally, it is determined that the acoustic power dissipation of the jet pump might be formulated as a function of the mean pressure difference
  9. Keywords:
  10. Traveling Wave ; Oscillating Flow ; Gedeon Streaming Phenomenon ; Thermoacoustic Engine ; Jet Pump ; Minor Pressure Losses

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