Journal of Mechanical Science and Technology

, Volume 30, Issue 5, pp 2059–2067 | Cite as

Optimization of a subsonic wind tunnel nozzle with low contraction ratio via ball-spine inverse design method

  • Hadi Hoghooghi
  • Mahdi Nili Ahmadabadi
  • Mojtaba Dehghan Manshadi
Article
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Abstract

The goal of wind tunnel design is to generate a uniform air flow with minimum turbulence intensity and low flow angle. The nozzle is the main component of wind tunnels to create a uniform flow with minimal turbulence. Pressure distribution along nozzle walls directly affects the boundary layer thickness, pressure losses and non-uniformity of flow velocity through the test section. Although reduction of flow turbulences and non-uniformity through the test section can be carried out by nozzles with high contraction ratio, it increases the construction cost of the wind tunnel. For decreasing the construction cost of nozzle with constant test section size and mass flow rate, the contraction ratio and length of nozzle should be decreased; that causes the non-uniformity of outlet velocity to increase. In this study, first, three types of nozzle are numerically investigated to compare their performance. Then, Sargison nozzle with contraction ratio of 12.25 and length of 7 m is scaled down to decrease its weight and construction cost. Having scaled and changed to a nozzle with contraction ratio of 9 and length of 5 m, its numerical solution reveals that the non-uniformity of outlet velocity increases by 21%. By using the Ballspine inverse design method, the pressure distribution of the original Sargison nozzle is first scaled and set as the target pressure of the scaled down nozzle and geometry correction is done. Having reached the target nozzle, numerical solution of flow inside the optimized nozzle shows that the non-uniformity just increases by 5% in comparison with the original Sargison nozzle.

Keywords

Subsonic wind tunnel Nozzle Contraction ratio Adverse pressure gradient Flow non-uniformity Inverse design method 
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Copyright information

© The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Hadi Hoghooghi
    • 1
  • Mahdi Nili Ahmadabadi
    • 1
  • Mojtaba Dehghan Manshadi
    • 2
  1. 1.Department of Mechanical EngineeringIsfahan University of TechnologyIsfahanIran
  2. 2.Department of Mechanical and Aerospace EngineeringMalek-Ashtar University of TechnologyIsfahanIran

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