Session: 31-09 Fan Inlet Distortion II

Paper Number: 151356

A Three-Dimensional Actuator Disk Model for Fan Response to Inlet Distortion: Part II – Applications 

A theory developed in a companion paper (Prasad, D. 2025, "A Three-Dimensional Actuator Disk Model for Fan Response to Inlet Distortion:~Part I -- Formulation," ASME GT2025-151355) for the distortion response of a fan stage is applied to several configurations.  The first of these is a conventional single-stage fan comprising a rotor and stator, subjected to a tip-dominated stagnation pressure distortion.  The response is highly three-dimensional, featuring a strong radial cross-flow and a distortion transfer with considerably greater spatial complexity than the excitation.  Upon varying the stage loading, it is found that, while the fan response near the tip is qualitatively similar to that obtained using parallel compressor theory, three-dimensional effects significantly alter the behavior in the inner span of the annulus.  Variations in the shape of the radial work distributions have a minor effect on the response although the behavior in the outer span exhibits a dependence on the gradient of the work distribution.  Conversely, the effect of introducing an Inlet Guide Vane is observed to be substantial, particularly on the distortion transfer.  This feature is exploited to optimize various aspects of the fan response  by employing circumferentially and radially nonuniform IGVs.  Finally, the response of the fan to a swirl distortion comprised of counter-rotating vortices is examined.  The upstream influence in this instance is observed to feature strong induced axial and radial velocities, while a substantial stagnation pressure response is generated downstream.

Presenting Author: Dilip Prasad Gulfstream Aerospace Corporation

Presenting Author Biography: Dr. Dilip Prasad is currently the Director of Propulsion, Environmental & Fuel Systems at Gulfstream, a position he has held since 2020. Prior to this, he served in a variety of technical and managerial roles at multiple divisions of Raytheon Technologies, including the Research Center, Pratt & Whitney, Rocketdyne and Collins Aerospace. Through his career, Dr. Prasad has applied analytical methods to solve problems related to diverse products, primarily in the aerospace industry, with occasional forays into other areas such as refrigeration and elevators. In the aerospace industry, he has contributed to the development of gas turbines, environmental control systems, fuel systems and rocket engines. Dr. Prasad’s educational background consists of an undergraduate degree in Mechanical Engineering from the Indian Institute of Technology at Madras and the SM and PhD degrees from MIT in the same field.

Authors:

Dilip Prasad Gulfstream Aerospace Corporation