Low Speed Aerocontrols Wind Tunnel

Room 104
Montgomery Knight Aerospace Building
School of Aerospace Engineering

The AeroControls tunnel is an open-return tunnel, with the test section is 1.07m x 1.07m (42 inch x 42 inch). It is powered by a 50HP Magnetek frequency-controlled AC Motor, with 7 moving blades, and 10 stators. The tunnel currently outputs freestream velocity ranging from 10 fps to 78 fps.

This tunnel is an ideal place to run experiments on new gadgets, because if the test object blows apart, it does no damage to the fan (unlike tunnels where the flow gets pulled into a fan downstream of the test section). It is easy to operate, so that experiments requiring continuous runs of many hours can be conducted. It has most of the characteristics of the Basic Aerodynamics Research Tunnel at NASA Langley Research Center.

History

The tunnel used to be powered with a DC motor, and the flow was driven with a 4-bladed axial-flow fan. A divergent section downstream of the fan connects to a large, square-section settling chamber.

The legend is that Dr. Ducoffe, former Director of the School of AE, did his M.S. thesis developing this wind tunnel. Having worked hard since the 1960s, and hosted every AE graduate since then in the aerodynamic laboratory courses, the tunnel has grown weary. The fan motor was beginning to give out, with some scary events occurring in the past few years. It was also too noisy to permit experiments involving acoustic measurements or clean flow-control experiments. The speed control was done using a dial. Since the motor speed depended on voltage, it fluctuated considerably (a few percent!), so that the operator had to continually adjust the dial. This could prevent drift of the mean velocity, but it contributed to the turbulence intensity. As our measurement devices and techniques were refined in the late 1980s - `90s, and we could measure the precise frequency bandwidth of some phenomenon which depended on flow velocity, our accuracy was limited by these fluctuations in the freestream velocity.

About 1998, we were able to find money (not much) to get a new fan and motor that is currently operational. The AC-DC conversion, which was noisy, is gone. The motor-fan combination is sized to be about twice as powerful as their predecessors. However, money constraints prevented any extensive tunnel re-design, and the fan is basically an industrial blower. The fairings, etc. which we installed are pretty basic: we had to get the tunnel up and running within 2 weeks of installing the fan, because Undergraduate Fluid Dynamics Lab needed it.

Current Status (Feb, 2000)

Since not a lot of resources were invested into tunnel re-design and the fan (which is basically an industrial blower), the tunnel characteristic is not as good as the previous setup. As of Winter, 1999, the key characteristics were: A team of two people from AE4010, flow diagnostic class, worked on improving the tunnel on Winter Quarter, 1999. For their report, click here.

Several improvements were done, including:

  • Removal of the safety screen

  • Figure 1: Inlet with Safety Screen

    Figure 2: Inlet without Safety Screen
  • Mouting of a Bell-Shaped Inlet

  • Figure 3: Overall Feature of the Bell-Shape Inlet

    Figure 4: Side View of the Bell-Shape Inlet
  • Split first down stream screen and second screen were replaced and repaired.

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    Which resulted in the following improvement

    The tunnel is still in progress of improvement work as of Spring, 2000

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