Session: 01-18 Inlets, Nozzles, Mixers and Nacelles III

Paper Number: 129402

129402 - Effect of Geometry Modification of a Double Entrance Y-Duct Inlet on Aerodynamic Performance With High Speed Flow 

Certain aircraft configuration utilize embedded gas turbine engine which require offset inlet to direct oncoming air to the engine face. Y-duct inlets are commonly used, especially in military aviation, due to their versatility and aerodynamic performance. Y-duct inlets consist of two symmetrical S-ducts merging to a single duct in the shape of the letter `Y`. These ducts are configured based on the operational requirements and geometric limitations of the aircraft in which they are installed. Y-duct geometry is defined by several parameters including vertical and horizontal offset, entrance aspect ratio, centreline curvatures, bend radii, and diffusion ratio. Similar to a single S-duct inlet, the combination of bends and area diffusion in Y-duct often leads to adverse pressure gradients and separated flow. The merging of the two S-ducts before the exit leads to further degradation of performance and results in decreased static and total pressure recovery, increased pressure distortion, and secondary flows at the engine face. These conditions degrade downstream engine performance and can affect the safety of the aircraft. Work completed at the Royal Military college of Canada has investigated the performance of two Y-duct designs to study the effect of certain geometric parameters on duct performance. First, a baseline duct was created and its performance was evaluated at an entrance Mach number of Ma = 0.63. The baseline duct was originally designed for Ma = 0.80 entrance flow; however, the flow choked in the Y-duct at lower Ma = 0.63. The test article was manufactured in plastic using 3D printing. Streamwise static pressure was measured along 4 radial positions and total pressure and three-dimensional velocity was measured using a 5-hole probe at the exit plane, also called Aerodynamic Interference Plane (AIP). The measurements were used to evaluate static and total pressure recovery as well as to determine the presence of secondary flows in the duct. The baseline duct had a total pressure recovery of 92.1% and a bulk swirl of -1.38 deg with the presence of strong secondary flows at the engine face. A modified Y-duct was then designed based on the observations made for the baseline duct. At an inlet speed of Ma = 0.63 this duct showed notable performance improvements including 97.7% total pressure recovery and 0.77 deg bulk swirl and a reduction in the intensity of secondary flows. Also, the modified Y-duct was able to run without choking with Ma = 0.8 entrance flow. This work aims to develop the understanding of relationships between geometric parameters and performance of Y-duct type inlets.

Presenting Author: Ben Gilbart Royal Military College of Canada

Presenting Author Biography: 2Lt Ben Gilbart is a postgraduate student at the Royal Military College of Canada (RMC) in Kingston Ontario. He completed his undergraduate degree in aeronautical engineering from RMC in May of 2022. During his time at RMC, he was a Cadet Division leader taking command of 1/4 of the cadet wing at RMC. Ben has on the job experience working with two Royal Canadian Airforce squadrons in the field of aircraft maintenance at 8 Wing Trenton Ontario. Ben is an avid runner and a regularly enjoys rowing and bouldering.

Authors:

Ben Gilbart Royal Military College of Canada
Courtney Rider Royal Military College of Canada
Asad Asghar Royal Military College of Canada
William Allan Royal Military College of Canada
Robert Stowe Valcartier Research Centre, Defence Research and Development Canada
Rogerio Pimentel Valcartier Research Centre, Defence Research and Development Canada