Title: Hypersonic Ludwieg Tube Design and Future Usage at the US Air Force Academy
Abstract: Hypersonic flows are usually characterized by the presence of strong shocks and equilibrium or nonequilibrium gas chemistry. Accurate prediction of these effects is critical to the design of any vehicle that flies at hypersonic velocities. The pressures and skin friction acting on the surface of the vehicles are integrated over the complete configuration to define the aerodynamic forces (e.g., lift, drag, pitching moment, and control surface effectiveness). The peak heat-transfer rate and the heating load are mapped over the vehicle surface as part of the process to design the thermal protection system. All of these are challenging parameters to predict at hypersonic speeds, requiring specialized experimental facilities or advanced computational simulation tools. Toward improving our ability to understand these flows, the U.S. Air Force Academy Department of Aeronautics will soon place into service a Mach 6 Ludwieg tube. This facility will enable the Academy to be better prepared to support the hypersonic research goals of the Department of Defense and other organizations. A Ludwieg tube is a high speed wind tunnel which does not require a total pressure control device or large settling chamber which is common for conventional blow-down tunnels. This greatly reduces the size and cost of operating the tunnel, since large compressors, heaters, and pressure vessels are not required for operation. The operational costs for a Ludwieg tube have been further reduced by the use of a fast-acting valve instead of the traditional bursting diaphragm. The facility will be compatible with the Boeing/AFOSR Mach 6 Quiet Tunnel at Purdue University, and will be able to support work from that facility, such as hypersonic transition. In addition, the facility will be able to support one of the difficult flow regimes encountered by NASA, namely acquiring data on blunt vehicles typical of lower ballistic coefficient configurations necessary for space activities. Finally, the facility will be able to conduct research on shock wave/boundary layer interactions at hypersonic speeds, which will support research for hypersonic air-breathing propulsion for future projects.
Publication Year: 2012
Publication Date: 2012-01-09
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 21
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