Design of a Hypersonic Expansion Tube for Rutgers University

A new hypervelocity expansion tube is under development for high-speed testing at Rutgers University. The designed expansion tube will consist of three fundamental sections: driver, driven, and expansion lengths. Operating under the same principles as a shock tube, the driver and driven lengths are separated by a double diaphragm to maintain control over tunnel actuation. The driven and expansion sections are subsequently separated by a Mylar second diaphragm, to be incinerated upon arrival of the initial shock in the driven. The entire tube will rest on castors to allow for ease of reloading of the diaphragms. At the end of the expansion section, the flow exhausts into a free-jet test section and dump tank, to contain the spent gases for recovery. The facility has been designed to operate at Mach 8 for ideal test conditions. Upon completion of the expansion tube, a series of experiments are being developed to examine the flow conditions in an empty tube, and using a common test article for comparison with the literature.