To advance the state-of-the-art in the understanding of the aerodynamic performance and installation effects of UHBR engines with AAN, a synergistic approach that uses wind-tunnel testing and Computational Fluid Dynamics (CFD) was followed, with the latter informing and guiding the former in terms of development of the experiment, and then the former providing validation data for the latter. The following work has been performed in AvAUNT to achieve its objectives:
1.- Design of rig (simulator) and models (Nozzle concepts):
Involving rig sizing, the rig external and internal aerodynamics studies, the mechanical and structural design, and the layout of the instrumentation for data acquisition.
2.- Manufacturing and assembly of rig and models:
Including manufacture of all rig and models parts and the installation of the instrumentation. The rig and the three nozzle concepts have been assembled and safety pressure tested and inspected.
3.- Commissioning of rig and models:
The rig and its systems have been commissioned in ARA's Propulsion Test House (PTH) prior to being declared ready for wind-tunnel testing at ARA's Transonic Wind Tunnel (TWT). This included checks on high-pressure air systems, instrumentation, data acquisition systems and calibration of the new 5-component flow-through balance. The performance of the rig and its systems has been quantified by means of analysing data collected in static blow trials simulating those planned for the wind-tunnel test campaign.
4- Wind-tunnel test and analysis of the results:
The AvAUNT wind-tunnel test took place at ARA’s TWT and was completed in July 2022. The final test matrix contained all the rig configurations planned: 3 nozzle concepts in isolated and installed configurations, covering the entire speed envelope (M=0.2 - M=0.85) and range of nozzle pressure ratios (NPR) desired.
In order to post-process the wind-tunnel results, a new set of data reduction equations and methodology has been developed and implemented under AvAUNT and used to extract nozzle performance coefficients to support the analysis of the wind-tunnel test data.
5 - CFD simulations of rig with models:
Numerical simulations of a reduced test matrix have been performed following a two-step approach.:
The first step focuses on the development and understanding of the correct modelling strategies for these types of nozzles. Geometric characteristics, mesh generation, turbulence modelling, boundary conditions and numerical schemes have been investigated considering 2D geometries. The outcomes from this analysis have then been utilised to inform the modelling strategies of the 3D configurations of the adaptive area nozzles concepts.
In the second step, 3D models of the different nozzles’ configurations have been “cleaned-up”, meshed and simulated. The main purpose of the second phase was to achieve a better understanding of the performance and of the flow features which develop for AAN configurations. Therefore, typical performance parameters such as discharge coefficients and thrust coefficients for the different nozzle configurations have been evaluated and analysed for both the isolated and installed scenarii.
The main exploitable results achieved in AvAUNT are listed below:
- Meshing and CFD simulation strategy for new AAN: QUB will be able to exploit the learning acquired through the creation of the methodology to mesh the AAN concepts and pass it onto the next generation of engineers via university lectures.
- Dual Stream Jet Propulsion Rig: The AvAUNT rig is a unique simulator that allows experimental test and evaluation of large-scale models of future nozzle concepts in isolated and installed configurations up to transonic speeds. The rig is already being exploited as it is a key element to deliver the objectives of the Clean Sky 2 project ODIN. Moreover, ARA is seeking to exploit this result further in research and commercial basis. Other development or improvements of technology required to create the rig, such as the new 5-component flow-through balance design can be ported to other applications.
- Dataset: The data from CFD simulations and wind-tunnel test, as well as the analysis and conclusions obtained, can be exploited by the Topic Manager who can use it to inform future AAN concepts.
- The learning acquired from the work carried out in AvAUNT will allow the continuation of the advancement of test and evaluation practices of AAN and other nozzle concepts
Project results and other project information have been disseminated through the project website, social media platforms, technical seminars and university sessions. A conference paper on the development of the novel dual stream jet propulsion rig will be presented at the AIAA SciTech Conference.
