Hypersonic wind tunnel

A hypersonic wind tunnel is an experimental facility in which can generate flows at hypersonic speed. The achievable speeds are in the range between Mach 5 and 15 as well as supersonic wind tunnels the hypersonic wind tunnels are driven only briefly; a continuous operation is not possible because of the enormous power requirements. Hypersonic wind tunnels operate at very high pressures, and by the sharp temperature drop of the flow in the expansion in the nozzle, a preheating of the gas is necessary to prevent liquefaction. Due to the high pressures and high temperatures, the material loading is critical, so that a cooling of the nozzle may be necessary. A hypersonic wind tunnel for high bandwidth is the shock tube.

Technological problems

The following points are critical in the design of a hypersonic wind tunnel:

• Supply with gas of high temperature and pressure for the required test period
• Accuracy of the initial conditions and thus reproducibility of the measurements
• Failure of the structure due to overheating
• Sufficiently fast data acquisition and instrumentation
• Energy supply

Example: The production of a flow, the 5.5 km / s corresponds to 45 km altitude, would require temperatures of about 9000 K and a pressure of 3 MPa (30 bar ).