Shock tube
A shock tube is a wind tunnel with which very high flow velocities can be generated for very short times (0.24 s) in a small measuring section (0.8 m length and 1.2 m² cross section). The measurement time depends on the length of the two pipes. The test is ended when the shock wave reflected on the front wall reaches the measuring section.
The shock tube is a closed system made up of two tubes that are initially separated by a membrane . One of the two tubes, the compression tube, is inflated to a high pressure. The other tube, the shock tube, is filled with the test gas to be examined at a significantly lower pressure in the millibar range. Different gases can be found in the two pipe halves. A maximum of Mach 6 can be achieved with air. With other gases (argon, helium, nitrogen, hydrogen) up to Mach 26 can theoretically be achieved.
By mechanical action or when the load limit is reached during inflation, the membrane bursts and the impact is triggered. At the same time, a dilution wave advances into the compression tube and a compression shock advances into the shock tube. The gas in the shock tube is strongly compressed and heated by the compression shock.
In the high enthalpy channel, a large-scale experimental facility at the German Aerospace Center , a shock tube 60 meters in length is used to simulate the physical conditions when landing capsules from spaceships re- enter the earth's atmosphere . Here are temperatures of up to 10,000 degrees Kelvin and flow velocities of reach up to 6,000 m / s.
See also
Web links
- Robert J. McMillan: Shock Tube Investigation of Pressure and Ion Sensors Used in Pulse Detonation Engine Research. Air Force Institute of Technology, Thesis (MS) 2004.