CFD Investigation of Air-Water Test Stand for Three-Stream Airblast Reactor Feed Injector

A large-scale parametric air-water test stand (AWTS) study involving more than 40 evaluations was carried out for the purposes of three-stream airblast reactor feed injector optimization; a subset of seven air stream combinations is discussed here. The role of CFD as a supplement to, or a replacement for, air-water testing is of great industrial interest. To this end a set of CFD experiments was carried out to mimic the AWTS study. A compressible geometric reconstruction Volume of Fluid (VOF) method was used to simulate the three-stream interaction. Pressure responses, spray opening characteristics near the feed injector face, and spray distribution were primary measures for both the AWTS and CFD programs. It was found that, over the range of variables studied, there was a partial match between CFD and AWTS results; some measures matched quantitatively, others qualitatively, and some did neither. A self-exciting, pulsatile spray pattern was achieved in CFD and AWTS, and an interesting transition in spray bursting character occurred at moderate inner air flows. Overall, it is shown that the CFD method contained herein can be used to supplement, but not replace, air-water testing for said injector configuration.