The Two-Way Training of Shape Memory Alloys Vortex Generators Manufactured in a Selective Laser Melting Process

A benchmark study of shape memory alloy delta wing vortex generators made in a selective laser melting process is reported in this paper. The equiatomic TiNi active vortex generators (VGs) were thermally two-way trained to change their shapes; a protrusion which intrudes into the incoming air flow at high temperatures to enhance heat transfer, while maintaining a low profile at low temperatures to minimise flow pressure losses. The VGs manufactured in the SLM process were compared against VGs which were made from commercially available thin sheets of TiNi. Promising results were obtained after the SLM manufactured active VGs were two-way trained. When their temperatures were varied from 20o to 65oC, the VGs responded by increasing their angles of attack from 10o to 38o and as the designs were two-way trained, they regained their initial position and shape at a lower temperature. The benchmarking exercise found that the SLM process offered more control over the VG shape, size and design complexities. The preparation procedures for the SLM active VGs were also shortened with the elimination of the heat treatment process. The commercially available thin TiNi sheets, however, gave a shorter response time and were easier to deform during the thermo-mechanical training cycl