Abstract:
Hypersonic Ludwieg tube tunnel is one of the most important ground facilities for hypersonic aerodynamic research. To some extent the high requirement of a large laboratory space due to the long straight storage tube of the Ludwieg tube tunnel precludes the establishment of this hypersonic aerodynamic facility for fundamental research purposes. To tackle this issue, this work reports the aerodynamic design of a hypersonic Ludwieg tube tunnel with a double-bent storage tube, and special emphasis was placed on the tunnel’s unsteady starting process and the influence of the double-bent storage tube on the flow field. Based on the aerodynamic design a Mach 6 Ludwieg tube tunnel with a double-bent storage tube has been newly built and the first shakedown results agree well with the numerical prediction. It reveals that the propagation of expansion waves in the storage tube is affected by the double-bent tube, resulting in a weak total pressure fluctuation in the storage tube. By choosing a proper diameter ratio between the bend and the storage tube, the influence of the storage tube bend can be neglected.