A CFD Investigation of IGV Flow Vectoring by Counter Flow Blowing

This paper describes a CFD analysis conducted to examine the impact of counter-flow blowing (CFB) on a row of uncambered, circulation-controlled (CC) inlet guide vanes (IGVs). In addition to a Coanda jet blown over the rounded trailing edge of the IGV blade, a second slot was placed on the pressure surface near the trailing edge to inject air upstream, i.e., in a counter-flow direction. Two blade shapes were modeled, each with four basic combinations of Coanda blowing and CFB, and the results were compared to flow turning and loss as modeled for a typical flapped IGV. The Advanced Ducted Propfan Analysis Code (ADPAC) was used to perform the 2-D simulations. While neither of the modified IGVs matched the 39-degree flow turning capability of the flapped IGV, CFB was predicted to augment flow turning by up to 5.3 degrees on the first geometry and up to 2.6 degrees on the second geometry. Cascade losses for the modified IGVs were more than twice as high as the flapped IGV, with the only exception being equivalent losses generated for Coanda-only blowing.