Fan Casing Treatment Development and Experimental Validation
Abstract
The purpose of this action is to provide FY24 CR3 funds, in the amount of $200K, for a new start Grant with Purdue University; GRANT14007076.--Abstract # Approved for Public ReleaseFan Casing Treatment Development and Experimental ValidationProgram Officer: Steve Martens, Ph.D.; Power, Propulsion, and Thermal ManagementOffice of Naval Research Code 35, Air Warfare and WeaponsAircraft engines operating in naval fighter applications have unique challenges, particularly for the fan. Navy fans have operability limitations driven by: highly loaded airfoils, inlet distortion due to the shape of the inlet and aircraft maneuvers, and steam / hot gas ingestion. These three demands not only pose significant challenges to the performance of the engine, but they will intensify with next generation aircraft and propulsion systems. Inlet distortion will worsen as inlets shorten and become more embedded for low-observability aircraft. Additionally, unmanned aircraft could execute maneuvers that would also exacerbate the distorted inlet flow. Finally, aircraft catapulted off the deck of a carrier pass through a steam cloud produced by the catapult creating a temperature inlet distortion during takeoff. Therefore, there is a need to de-sensitize the fan to these harsh conditions while still maintaining good efficiency, directly impacting engine fuel consumption.One proven way to address reduced stall margin is through the use of casing treatments. These can be liners or specially-shaped inserts applied to the casing (the engine housing) over the fan blade tips to adjust the air flow over the tips. Conventional casing treatments are nearly always accompanied with a decrease in engine efficiency, resulting in a tradeoff between increased stall margin with decreased efficiency. The objectives of this research are to develop new casing treatments that exhibit stall margin enhancement without the efficiency penalty at peak efficiency conditions.Three types of casing treatments will be developed in this 3-year, $905K research project. The first is referred to as Clocked Recirculation Channels, which make useof the different pressure fields set up by the shock wave at different loading conditions. Thus, by circumferentially shifting the extraction port from the ingestion port of the recirculation channel, the casing treatment can be set up to essentially shut off at peak efficiency conditions and only activate at near stall to enhance the stall margin. The second type of casing treatment that will be developed is an Acoustic Resonator Casing Treatment, which will mitigate the oscillation of the shock wave by dampening out thefrequency associated with shock oscillation utilizing Helmholtz resonators. Finally, the third type of casing treatment to be developed is a Non-Axisymmetric Casing Treatment, which will be tailored to the asymmetric inlet distortion pattern introduced to the fanresearch facility.A new fan research facility was developed at Purdue University in collaboration with the Office of Naval Researchfor casing treatment research. Low-cost, fast-turnaround testing of the casing treatment concepts is enabled by additive manufacturing of the casing treatments. This will allow for close coupling between the computational and experimental research efforts, where results from a test will allow for improved understanding and validation of modeling approaches leading to an iterative convergence on optimized casing treatment designs.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 11, 2024
- Source ID
- N000142412273
Entities
People
- Nicole Leanne Key
Organizations
- Office of Naval Research
- Purdue University
- United States Navy