International Journal of Fluid Mechanics & Thermal Sciences

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Experimental Investigation of Pulsating Turbulent Flow Through Diffusers

Received: 29 November 2016    Accepted: 26 December 2016    Published: 16 January 2017
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Abstract

This paper presents the results of an experimental study on a pulsating turbulent flow through conical diffusers with total divergence angles (2θ) of 12, 16, and 24, whose inlet and exit were connected to long straight pipes. To examine the effects of the divergence angle and the nondimensional frequency on flow characteristics, experiments were systematically conducted using a hot-wire anemometry and a pressure transducer. Moreover, the pressure rise between the inlet and the exit of the diffuser was analyzed approximately under the assumption of a quasi-steady flow and expressed in the form of simple empirical equations in terms of the time-mean value, the amplitude, and the phase difference from the flow rate variation. The expressions are in good agreement with the experimental results and very useful in practice. With the increase in the Womersley number, α, and 2θ, the sinusoidal change in the phase-averaged velocity, W, with time becomes distorted, and the W distributions show a more complicated behavior. For the flow at α=10 in the diffusers with large 2θ, the distributions of W are depressed on the diffuser axis. In contrast, for the flow at α=20, W has a protruding distribution on the diffuser axis.

DOI 10.11648/j.ijfmts.20160204.12
Published in International Journal of Fluid Mechanics & Thermal Sciences (Volume 2, Issue 4, December 2016)
Page(s) 37-46
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Pulsating Flow, Diffuser, Velocity Distribution, Pressure Distribution, Womersley Number, Divergence Angle

References
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[4] Mochizuki, O., Kiya, M., Shima, Y. and Saito, T. (1997). Response of separating flow in a diffuser to unsteady disturbances, Transactions of the Japan Society of Mechanical Engineers, Series B, Vol. 63, No. 605, pp. 54-61 (in Japanese).
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[9] King, C. V. and Smith, B. L. (2011). Oscillating flow in a 2D diffuser, Experiments in Fluids, Vol. 51, pp. 1577-1590.
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[11] Nabavi, M. (2009). Steady and unsteady flow analysis in microdiffusers and micropumps: a critical review, Microfluidics and Nanofluidics, Vol. 7, pp. 599-619.
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[13] Sun, C. -L., Tsang, S. and Huang, H. -Y. (2015). An analytical model for flow rectification of a microdiffuser driven by an oscillating source, Microfluidics and Nanofluidics, Vol. 18, pp. 979-993.
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[17] Erath, B. D. and Plesniak, M. W. (2010). An investigation of asymmetric flow features in a scaled-up driven model of the human vocal folds, Experiments in Fluids, Vol. 49, pp. 131-146.
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Author Information
  • Department of Mechanical Engineering, Faculty of Engineering, Kindai University, Higashi-Hiroshima, Japan

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    Masaru Sumida. (2017). Experimental Investigation of Pulsating Turbulent Flow Through Diffusers. International Journal of Fluid Mechanics & Thermal Sciences, 2(4), 37-46. https://doi.org/10.11648/j.ijfmts.20160204.12

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    Masaru Sumida. Experimental Investigation of Pulsating Turbulent Flow Through Diffusers. Int. J. Fluid Mech. Therm. Sci. 2017, 2(4), 37-46. doi: 10.11648/j.ijfmts.20160204.12

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    AMA Style

    Masaru Sumida. Experimental Investigation of Pulsating Turbulent Flow Through Diffusers. Int J Fluid Mech Therm Sci. 2017;2(4):37-46. doi: 10.11648/j.ijfmts.20160204.12

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  • @article{10.11648/j.ijfmts.20160204.12,
      author = {Masaru Sumida},
      title = {Experimental Investigation of Pulsating Turbulent Flow Through Diffusers},
      journal = {International Journal of Fluid Mechanics & Thermal Sciences},
      volume = {2},
      number = {4},
      pages = {37-46},
      doi = {10.11648/j.ijfmts.20160204.12},
      url = {https://doi.org/10.11648/j.ijfmts.20160204.12},
      eprint = {https://download.sciencepg.com/pdf/10.11648.j.ijfmts.20160204.12},
      abstract = {This paper presents the results of an experimental study on a pulsating turbulent flow through conical diffusers with total divergence angles (2θ) of 12, 16, and 24, whose inlet and exit were connected to long straight pipes. To examine the effects of the divergence angle and the nondimensional frequency on flow characteristics, experiments were systematically conducted using a hot-wire anemometry and a pressure transducer. Moreover, the pressure rise between the inlet and the exit of the diffuser was analyzed approximately under the assumption of a quasi-steady flow and expressed in the form of simple empirical equations in terms of the time-mean value, the amplitude, and the phase difference from the flow rate variation. The expressions are in good agreement with the experimental results and very useful in practice. With the increase in the Womersley number, α, and 2θ, the sinusoidal change in the phase-averaged velocity, W, with time becomes distorted, and the W distributions show a more complicated behavior. For the flow at α=10 in the diffusers with large 2θ, the distributions of W are depressed on the diffuser axis. In contrast, for the flow at α=20, W has a protruding distribution on the diffuser axis.},
     year = {2017}
    }
    

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  • TY  - JOUR
    T1  - Experimental Investigation of Pulsating Turbulent Flow Through Diffusers
    AU  - Masaru Sumida
    Y1  - 2017/01/16
    PY  - 2017
    N1  - https://doi.org/10.11648/j.ijfmts.20160204.12
    DO  - 10.11648/j.ijfmts.20160204.12
    T2  - International Journal of Fluid Mechanics & Thermal Sciences
    JF  - International Journal of Fluid Mechanics & Thermal Sciences
    JO  - International Journal of Fluid Mechanics & Thermal Sciences
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    EP  - 46
    PB  - Science Publishing Group
    SN  - 2469-8113
    UR  - https://doi.org/10.11648/j.ijfmts.20160204.12
    AB  - This paper presents the results of an experimental study on a pulsating turbulent flow through conical diffusers with total divergence angles (2θ) of 12, 16, and 24, whose inlet and exit were connected to long straight pipes. To examine the effects of the divergence angle and the nondimensional frequency on flow characteristics, experiments were systematically conducted using a hot-wire anemometry and a pressure transducer. Moreover, the pressure rise between the inlet and the exit of the diffuser was analyzed approximately under the assumption of a quasi-steady flow and expressed in the form of simple empirical equations in terms of the time-mean value, the amplitude, and the phase difference from the flow rate variation. The expressions are in good agreement with the experimental results and very useful in practice. With the increase in the Womersley number, α, and 2θ, the sinusoidal change in the phase-averaged velocity, W, with time becomes distorted, and the W distributions show a more complicated behavior. For the flow at α=10 in the diffusers with large 2θ, the distributions of W are depressed on the diffuser axis. In contrast, for the flow at α=20, W has a protruding distribution on the diffuser axis.
    VL  - 2
    IS  - 4
    ER  - 

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