Read the full press release from AIAA by following the link below.
In response to NASA SBIR topic A1.02 Quiet Performance – Propulsion Noise Reduction Technology, the team of Techsburg, AVEC, and Ampaire proposes implementation and design application of a low-order noise modeling tool for installed ducted fan-rotor aerodynamic and acoustic analysis. Named the “Installed Ducted-Fan Noise Model” (IDFNM), and following after Techsburg/AVEC’s work in noise modeling for pusher propellers, this tool will offer early-stage design analysis support for installed ducted fan-rotor propulsion systems by capturing the aerodynamic unsteady loading and noise sources resulting from inflow distortion or non-uniform inflow. This tool is well suited for highly integrated and innovative propulsion airframe integration concepts, such as boundary layer ingesting fan configurations. Application of this tool will focus on a highly-efficient design for Ampaire’s TailWind electric aircraft. In collaboration with Ampaire, Techsburg and AVEC will work to design an optimized first-generation BLI ducted fan for the TailWind passenger aircraft. During Phase I, Techsburg and AVEC will work on design tool maturation, and also conduct a propulsor design trade study, complete with aerodynamic and acoustic predictions, for the TailWind aft-mounted, boundary layer ingesting ducted fan. Phase II work will include an anechoic wind tunnel test program for validation of prediction tools over a range of operating conditions and the delivery of an integrated low-order noise prediction software package for the “Installed Ducted-Fan Noise Model.
Part of the life cycle of many industrial gas turbines often includes one or more performance uprates, typically defined by an increase in pressure ratio and/or firing temperature. In the process the hot section is usually only minimally modified due to cost and schedule limitations. As a result, the turbine section may operate at off-design with the last stage being most impacted. The exhaust system is thereby subjected to variations in inlet flow conditions, specifically the velocity and the flow angle, which adversely affect pressure recovery and impact overall engine performance. Similar variation in turbine exhaust inlet flow conditions arise for industrial two-shaft engines with power turbines operating at a wide range of speeds.
This paper describes studies completed using a quarter-scaled rig to assess the impact of turbine exit swirl and strut angular positioning on a turbine exhaust system that features an integral diffuser-collector. Advanced testing methods as well as flow visualization techniques are applied to ascertain exhaust performance for a range of inlet conditions aerodynamically matched to flow exiting an industrial gas turbine. Computational Fluid Dynamics (CFD) was extensively used to complement testing with the aim to ascertain the design phase and off-design performance prediction capability of modern day numerical tools.
A prototype code to facilitate reduced-order modeling of propeller inflow distortion noise was completed and successfully validated during our 6-month Phase I project. The “Installed Propeller Noise Model” code (IPNM) accepts both aircraft wing/tail surface geometry input or prescribed propeller inflow data via CFD solution or other means. During Phase II, the IPNM code will be developed in a deliverable software tool to the Army. Maturation of the IPNM noise modeling code will be enhanced by experimental measurements of propeller blade loads on rotating through inflow distortion generated by upstream airfoils. In addition, hot film flow measurements in the upstream propeller potential field will lend understanding to the inflow-propeller blade load coupling and associated noise generation.