Avio Group with EnginSoft SPA
Modern aero-engine development is driven by a number of factors and requirements, but probably none greater than the requirement to increase overall efficiency. This is largely due to environmental concerns and the ever more stringent emission targets that result, as well as a desire to insulate operators from rises in fuel costs through reduced consumption.
An effective cooling strategy is therefore critical in order that efficient operation is possible throughout the entire operating range. To put this in perspective, the diameter of an aerospace turbine is often greater than 1 meter, while the required clearance might be less than 0.5mm. This extreme design challenge can only be accurately and reliably met when the engineer is in a position to consider the entire system and its physics; fluid dynamics, thermal effects, and structural deformations must be considered together in a multi-physics approach that gives the designer access to the entire picture.
The Multi-Physics Approach
The numerical multi-physics approach by Avio Group in Italy described here is an automatic procedure developed by Avio with the help of EnginSoft sPA. The approach is capable of managing the operation and data transfer of three different commercial software tools:
- MSC.P-thermal: Thermal solver used for the computation of the temperature distribution in the solid structure;
- MSC.Marc: Deformation analysis tool used for the computation of solid structure deformation;
- Flowmaster® from Mentor Graphics: System level fluid-dynamic solver used for the computation of the flow field through the gas turbine.
The multi-physics simulations carried out are driven by a specific FORTRAN library implemented into MSC.P-thermal. The FORTRAN library manages the co-simulation by invoking the fluiddynamic solver (Flowmaster) and the deformation analysis software (MSC. Marc) when required. In particular, the call to Flowmaster is managed by a coupling interface procedure implemented ad hoc in Visual Basic. The coupling interface manages the data transfer between the two codes and manages the fluid-dynamic simulation in all its parts by setting component and simulation data, running it and exporting the results.
System Level Simulations
To guarantee the required design accuracy, the entire system needs to be modeled, integrating rotor and static systems of the entire turbine. In particular, all secondary air systems, cooling circuits, active clearance control devices and the main flow path were considered in this system level analysis. The simulation of the entire engine mission had to consider idle, take off, cruise, approach and landing phases. A complete simulation lasts about one week and requires about 5000 Flowmaster simulations and about 3000 deformation analyses. All simulations and data transfer are automatically controlled and managed by the thermal solver through the automatic interface procedure as described above.
Avio's implemented numerical multiphysics approach has been validated and was able to achieve a better understanding of the thermal behavior of the turbine during the entire engine mission early in the design phase. This, in turn, allowed them to define the optimal geometries, materials and cooling mass flows for active clearance control. In the final analysis, the implemented multi-physics integrated approach described here, when used early in the design phase, allows the definition of the optimal clearances capable of achieving high efficiency and, as a consequence, a reduction in fuel consumption. A fundamental consideration with respect to meeting future aerospace emission limits.
Avio is a world leader in the design, development and manufacturing of aerospace propulsion components and systems for both civil and military aircraft. Avio works through the whole lifecycle of the products - from design to maintenance, repair and operations services. Avio is headquartered in Rivalta di Torino, Turin, Italy, and operates across four continents. It employs over 5,200 staff, 4,500 of whom are based in Italy. Avio was founded in 1908 and has played a crucial role in tackling the technological and business challenges of our time. Through continuous investment in R&D, and thanks to its relationships with the top Italian and international universities and research centers, Avio has developed leadership in technology and manufacturing.
EnginSoft is a premier consulting firm in the field of Simulation Based Engineering Science (SBES) with a global presence. It was founded in 1984, but its founder and initial employees had been working in SBES since the mid ‘70s. Throughout its long history it has been at the forefront of technological innovation and remains a catalyst for change in the way SBES and CAE technologies in general are applied to solve even the most complex industrial problems with a high degree of reliability.