Periodic Reporting for period 4 - AMBEC (Advanced Modelling Methodology for Bearing Chamber in Hot Environment)
Période du rapport: 2020-05-01 au 2023-10-31
The goal of the AMBEC project was to achieve a complete understanding of the physical phenomena in the bearing chamber of a gas-turbine engine and to create a reliable methodology able to calculate the heat transfer coefficient and the fluid flows for different zones of the bearing chamber depending on the key engine operation parameters.
The challenge of this task consists in a multiphase fluid in the bearing chamber, which is a mixture of the injected oil and air. Getting through the nozzle, the oil spreads over the bearing surface forming the oil film. The film is moving because of aerodynamic forces, gravity and viscosity. In parallel, it is influenced by the oil droplets, which fall on it from the bearing, as well as by the airflow, which can generate and carry out the droplets from the surface of the film. Because of this complex interaction, the oil film has a variable thickness along the circumference of the bearing chamber. This fact affects the process of heat exchange between the chamber walls and the air-oil mixture. Other facts that influence the heat-exchange processes are the shaft rotational speed, the pressure in the bearing chamber, the oil and air flow rates, the bearing chamber design and roughness of its walls, etc.
The AMBEC team combined an advanced CFD simulation and in-depth experimental research to study the heat exchange processes between air, oil drops, non-uniform oil film and bearing chamber walls in a multiphase ever-changing environment. It helped to create a versatile, accurate and user-friendly methodology, which will be an efficient instrument for the industrial design of compact bearing chambers operating in hot environment.
Application of AMBEC methodology will help engine developers to cut the time and effort required for the design and development of innovative compact bearing chambers and to ensure reliable operation of bearings in hot environment at lower oil and secondary air flow rates.
The challenge of this task consists in a multiphase fluid in the bearing chamber, which is a mixture of the injected oil and air. Getting through the nozzle, the oil spreads over the bearing surface forming the oil film. The film is moving because of aerodynamic forces, gravity and viscosity. In parallel, it is influenced by the oil droplets, which fall on it from the bearing, as well as by the airflow, which can generate and carry out the droplets from the surface of the film. Because of this complex interaction, the oil film has a variable thickness along the circumference of the bearing chamber. This fact affects the process of heat exchange between the chamber walls and the air-oil mixture. Other facts that influence the heat-exchange processes are the shaft rotational speed, the pressure in the bearing chamber, the oil and air flow rates, the bearing chamber design and roughness of its walls, etc.
The AMBEC team combined an advanced CFD simulation and in-depth experimental research to study the heat exchange processes between air, oil drops, non-uniform oil film and bearing chamber walls in a multiphase ever-changing environment. It helped to create a versatile, accurate and user-friendly methodology, which will be an efficient instrument for the industrial design of compact bearing chambers operating in hot environment.
Application of AMBEC methodology will help engine developers to cut the time and effort required for the design and development of innovative compact bearing chambers and to ensure reliable operation of bearings in hot environment at lower oil and secondary air flow rates.
AMBEC was a multidisciplinary project based on a combination of extensive experimental studies and advanced numerical simulation. Therefore, the AMBEC team was particularly focused on the planning and implementation of the following technical activities.
• Development of a comprehensive test matrix to study flow distribution and heat transfer phenomena in the bearing chamber in a hot environment. This matrix specified parameters like oil and air flow rates, temperature, rotation speed, and chamber wall roughness, outlining 129 test points.
• Design, manufacturing and commissioning a test vehicle and test bench for conducting planned multi-parametric studies. Special attention was given to selecting appropriate instrumentation for temperature, oil-air mixture flow rate, and oil film thickness measurements, crucial for understanding multiphase processes in the bearing chamber. Manufacturing of the test vehicle and bench components started in October 2019, with the AMBEC test bench becoming operational in June 2021.
• Development of the methodology able to reliably predict the heat transfer phenomena and the fluid flow distribution in the aero-engine bearing chambers. In this regard, a wide range of studies on multiphase flow characteristics and heat transfer phenomena in the bearing chamber were analysed; advanced two-phase modelling of thermal and hydraulic processes in the bearing chamber and a deep analysis of the modelling results and test data were carried on. As a result, an understanding of the physical phenomena in the bearing chamber and the methodology adaptation were achieved.
• Running an intensive experimental campaign in line with the developed test matrix and using the test vehicle and rest bench produced to generate the data for validating numerical simulations and refining the AMBEC methodology. Unfortunately, only 80% of planned test points were studied due to the Russian invasion of Ukraine and AMBEC test vehicle damage by the Russian missile attack.
Thanks to these activities, the following project results were generated:
• State-of-the-art experimental facility for bearing chamber processes studies
• Understanding of physical phenomena in bearing chamber that depend on geometrical and operation parameters
• Experimentally-validated methodology able to calculate heat transfer processes and fluid distribution in different zones of bearing chamber.
Project results were disseminated at international conferences (11th EASN Virtual International Conference, ASME Turbo Expo 2021, ASME Turbo Expo 2020, XXV International Congress of Propulsion Engineering) and in three peer-reviewed publications in conference proceedings (open access provided by the publisher or via Zenodo repository). All project publications are stored on the project website (www.ambec.eu).
Project results will be further exploited by the AMBEC Topic Manager (SAFRAN) for the development and TRL5-6 maturation of the Ultra high propulsive efficiency (UHPE) Demonstrator in the frame of Clean Sky 2 Engines ITD. Also, they will be exploited by the AMBEC partners for their business activities development (Ivchenko and Motor Sich) and further internal, contractual or publicly funded research (KhAI).
• Development of a comprehensive test matrix to study flow distribution and heat transfer phenomena in the bearing chamber in a hot environment. This matrix specified parameters like oil and air flow rates, temperature, rotation speed, and chamber wall roughness, outlining 129 test points.
• Design, manufacturing and commissioning a test vehicle and test bench for conducting planned multi-parametric studies. Special attention was given to selecting appropriate instrumentation for temperature, oil-air mixture flow rate, and oil film thickness measurements, crucial for understanding multiphase processes in the bearing chamber. Manufacturing of the test vehicle and bench components started in October 2019, with the AMBEC test bench becoming operational in June 2021.
• Development of the methodology able to reliably predict the heat transfer phenomena and the fluid flow distribution in the aero-engine bearing chambers. In this regard, a wide range of studies on multiphase flow characteristics and heat transfer phenomena in the bearing chamber were analysed; advanced two-phase modelling of thermal and hydraulic processes in the bearing chamber and a deep analysis of the modelling results and test data were carried on. As a result, an understanding of the physical phenomena in the bearing chamber and the methodology adaptation were achieved.
• Running an intensive experimental campaign in line with the developed test matrix and using the test vehicle and rest bench produced to generate the data for validating numerical simulations and refining the AMBEC methodology. Unfortunately, only 80% of planned test points were studied due to the Russian invasion of Ukraine and AMBEC test vehicle damage by the Russian missile attack.
Thanks to these activities, the following project results were generated:
• State-of-the-art experimental facility for bearing chamber processes studies
• Understanding of physical phenomena in bearing chamber that depend on geometrical and operation parameters
• Experimentally-validated methodology able to calculate heat transfer processes and fluid distribution in different zones of bearing chamber.
Project results were disseminated at international conferences (11th EASN Virtual International Conference, ASME Turbo Expo 2021, ASME Turbo Expo 2020, XXV International Congress of Propulsion Engineering) and in three peer-reviewed publications in conference proceedings (open access provided by the publisher or via Zenodo repository). All project publications are stored on the project website (www.ambec.eu).
Project results will be further exploited by the AMBEC Topic Manager (SAFRAN) for the development and TRL5-6 maturation of the Ultra high propulsive efficiency (UHPE) Demonstrator in the frame of Clean Sky 2 Engines ITD. Also, they will be exploited by the AMBEC partners for their business activities development (Ivchenko and Motor Sich) and further internal, contractual or publicly funded research (KhAI).
The key output of the project is the AMBEC methodology, which combines advanced numerical simulation of multiphase flows and heat transfer effects in the bearing chamber. It is much more advanced than the state-of-the-art approaches and methodologies thanks to the simulation of the oil film generation and motion with account for (i) the combined effect of interphase interaction, gravity and centrifugal forces as well as (ii) the possibility of the liquid film rupture onto the droplets with their further crushing and coagulation. Such a complex and innovative approach will ensure high accuracy of the calculation results.
Application of AMBEC methodology for design of the bearing chambers of the next-generation aircraft gas turbine engines will help to optimise the oil flow rate, thus, will result in less intensive operation of oil pumps, lower engine fuel consumption rate and less environmental impact in terms of СО2 and NOx emissions. On the other hand, the methodology application will have a positive influence on overall engine development costs and lead time, thus contributing to strengthening European engine manufacturers’ competitiveness in the global market.
Altogether, the AMBEC project outputs will contribute to the greening of EU aviation and more affordable mobility for European citizens and EU businesses.
Application of AMBEC methodology for design of the bearing chambers of the next-generation aircraft gas turbine engines will help to optimise the oil flow rate, thus, will result in less intensive operation of oil pumps, lower engine fuel consumption rate and less environmental impact in terms of СО2 and NOx emissions. On the other hand, the methodology application will have a positive influence on overall engine development costs and lead time, thus contributing to strengthening European engine manufacturers’ competitiveness in the global market.
Altogether, the AMBEC project outputs will contribute to the greening of EU aviation and more affordable mobility for European citizens and EU businesses.