An Additively Manufactured Small Footprint Wind Tunnel for Wall Jet and Particle Scavenging Studies*

Powder bed fusion is a fast-growing additive manufacture method. However, the quality of produced metal parts is often challenged by particle spatter in the build chamber. To remove the spatter particles, it is important to gain further understanding of particle scavenging process. 

The focus of this paper is on the design and the build of a wall jet wind tunnel as well as experimental test data of particle scavenging inside the wind tunnel. The wind tunnel is additively build and has a co-flow configuration where a small-scale open loop suction tunnel creates uniform free stream, and a blower generates a plane wall jet through a rectangular slot. The wind tunnel is also equipped with adjustable height build plate on which metal power can be spread, variable speed axial fan, diffuser, honeycomb, perforated plates, and parallel air filters. The build-in flexibility of the wind tunnel allows testing various of different cross-flow configurations. 

A high-speed camera captures particle motion across a wide range of test condition for a number of metal powers used in additive manufacturing including aluminum alloy AlSi10Mg, nickel-based superalloy Inconel 718, titanium alloy Ti-6Al-4V, steel alloy 4340, and 316L stainless steel. Particle tracking velocimetry (PTV) and a high frequency hot-wire air flow meter are coupled to measure time-averaged flow field data.