NASA’s Glenn Research Center is advancing the development of software tools aimed at predicting jet noise from aircraft engines. These tools will assist engineers in designing quieter and more efficient aircraft propulsion systems.
Jet Noise Prediction Software
The development of jet noise prediction software involves multiple codes, each with unique capabilities. One key program, JeNo, utilizes Lilley’s Acoustic Analogy along with Reynolds-Averaged Navier-Stokes (RANS) equations to predict jet noise. It is designed to provide rapid assessments, particularly for subsonic and low supersonic, unheated axisymmetric jets.
Another software tool, MGBK, was created prior to JeNo and focuses on analyzing jet noise trends from complex aircraft engine exhaust nozzles. MGBK has been instrumental in evaluating noise reduction techniques, particularly the use of chevrons on turbofan nozzles, which are commonly found on commercial aircraft.
Advanced Modeling Techniques
For more sophisticated analysis, V072 offers insights into rotor/stator interaction tone noise, assisting engineers in optimizing design parameters such as blade counts and spacing. TFaNS enhances this capability by not only calculating tone noise but also accounting for acoustic coupling effects among blade rows.
Linflux stands out for its ability to analyze realistic, three-dimensional flows and more complex blade geometries, requiring greater computational resources while delivering detailed noise predictions.
Broadband Noise Analysis and Propeller Noise
BFANS focuses on broadband noise generated by turbulence affecting rotor blades and stator vanes. By integrating experimental data from wind tunnel tests, this software helps identify the loudest components within fan stages. RSI, another tool, calculates the spectrum of noise resulting from fan rotor wake turbulence interacting with guide vanes.
WOBBLE targets propeller noise, predicting how varying inflow angles influence acoustic emissions. This model comprehensively addresses unsteady sources affecting propeller performance.
Noise from Supersonic Blades and Turbofan Analysis
The MPT code estimates “buzz saw” noise caused by rotor locked shocks in supersonic fan blades. It incorporates flow predictions from computational fluid dynamics to evaluate real-world variations in blade manufacturing and performance.
ADPAC, developed by Allison Engine Company in collaboration with NASA, focuses on modeling complex flows in short-duct turbofan engines. This validated computational fluid dynamics tool supports a range of specific aerodynamic analyses.
Copies of these software tools can be requested from NASA’s Software Catalog, allowing engineers and researchers to leverage these advanced technologies in their work.
Source: NASA
