Session: 01-13 Thermal Management and Aero-engine Oil Systems I

Paper Number: 123712

123712 - Effect of Flow Distortions on Pin Fins in the Entry Region of Circular Channels 

                Utilizing heat transfer augmentation features at the inlet of aircraft engines as an additional heat sink requires further understanding on entry region heat transfer and flow field interactions. The effect of asymmetric flow fields or distortions on entry region heat transfer has not been studied. Typically, distortion screens are attached to the inlet of an engine to quantify engine performance in non-ideal flow. Because the addition of augmentation features would create a near-wall distortion that would impact downstream aircraft components, comparing entry region features to standard distortion screens would provide insight on the performance impact to aircraft engines. This study investigates the effect of inlet distortion screens on pin fin entry region heat transfer, in order to understand if flow field disturbances would disrupt the benefits of augmented entry region heat transfer. In addition, this study investigates if the distortion caused by pin fin augmentation features can be superimposed with smooth entry region distorted flow, thereby enabling an estimate on engine performance costs by including entry region features in the distortion. Three distortion screens are investigated with pin fin arrays: tip, hub and asymmetric aircraft distortion, each tested at Reynolds numbers ranging from 150,000 to 350,000. Pin fin heat transfer performance is not significantly impacted by distortion screens. This is due to the near wall boundary layer impact of augmentation features overshadowing the effect of distortion screens. Thus, the pin fin array sensitivity to distortion screens is low, indicating that the viability of augmentation features in asymmetric flow is still acceptable. Due to the insensitivity of the near wall boundary layer for pin fin arrays with distortions, superimposing the smooth entry region distorted flow with the non-distorted pin fin array provides an adequate estimate of the flow field of the distorted pin fin array.

This abstract has been cleared for release, reference number: AFRL-2023-5017.

Presenting Author: Evan Lundburg Pennsylvania State University

Presenting Author Biography: Evan Lundburg is a Sr. Engineer in Aero Thermal Fluids at Pratt and Whitney. This work is a part of his PhD. Dissertation from Penn State in the ExCCL Lab. Previous research includes film cooling hole manufacturing and other work in entry region heat transfer.

Authors:

Evan Lundburg Pennsylvania State University
Stephen Lynch Pennsylvania State University
Michael Lyall Air Force Research Laboratory