1. CIMNE Fluid-Structure Interaction for Combustion Systems 36-Months Progress Meeting Queen's University of Belfast Belfast UK Jan 24

2. Pavel Ryzhakov: activities 1.Development of an updated lagrangian formulation of a fluid element 2.The structural part of the multi-physics code KRATOS, develeoped at CIMNE was utilized in order to perform the analysis of the structural response of the thin part of the liner (Twente test rig) 3.Smart interpolation tool in order to couple structural code of CIMNE with the fluid code of CERFACS (in progress)

3. Training and mobility 4-weeks stay at CERFACS, Toulouse, France. Computation of the structural response to the oscillating flame in the thin part of the liner. Work performed in cooperation with Mauro Porta

4. Interaction between unsteady flow and the elastic liner To be analyzed: The thin part of the liner of a research combustion chamber was analyzed. The experiments were performed at Twente University (The Nederlands) Thin liner

5. Interaction between unsteady flow and the elastic liner Input data: Pressure fluctuations on the inner surface of the liner (results of the Large Eddy Scale Simulation, done by CERFACS) Non-pulsating, unsteady flow (pressure fluctuations at 430 Hz), with steady inlet and outlet boundary conditions values up to 10 4 Pa

6. Interaction between unsteady flow and the elastic liner Model: The thin part of the liner (400x150 mm, wall thickness 15mm) was modelled and discretized by the mesh of ca. 17000 linear tetrahedras (6000 nodes). Boundary conditions: displecaments are fixed on both ends. Fixed displacements on both ends

7. Interaction between unsteady flow and the elastic liner Coupling: The locations of the nodes of the structural mesh was tranfered to the fluid simulation, and the data of interest (pressure) was read at those locations. The structure was loaded by these pressures. Fixed displacements on both ends

8. Interaction between unsteady flow and the elastic liner Structural solver: Multiphysics software KRATOS, developed at CIMNE. Direct temporal approach. Total simulation time=15 ms Here following options were used: -Bossak scheme for time integraion -Biconjugate gradient linear solver -Time step for the structural computation: 0.05 ms

9. Interaction between unsteady flow and the elastic liner Results: Displacement profile (of the node located 50 mm away from the edge of the upper wall)

10. Interaction between unsteady flow and the elastic liner Results: Velocity profile (of the node located 50 mm away from the edge of the upper wall)

11. Interaction between unsteady flow and the elastic liner Comparison: Results presented by Rob Huls (velocity evolution)

12. Interaction between unsteady flow and the elastic liner Results: Deflection of the structure at 4 time instances: 2 ms, 5 ms, 10 ms, 15 ms

13. Interaction between unsteady flow and the elastic liner Results: Deflection of the structure (x400 000)

14. Interaction between unsteady flow and the elastic liner Results: Deflection of the structure (x400 000)

15. Interaction between unsteady flow and the elastic liner Results: Principal stress:

16. Interaction between unsteady flow and the elastic liner Results: Analysis: Principal stress values of range of few MPa. (Material strength=400MPa) Period of oscillation of the structure: ~2ms Strcuture responds mostly to the accoustic mode of ~400 Hz

17. Interaction between unsteady flow and the elastic liner Conclusions: feasability of the fluid structure interaction for combustion chamber good comparison with experimental data temporal approach taking into account inertial effects (dynamic computation) necessary

18. Interaction between unsteady flow and the elastic liner Conclusions: displacements of structure of magnitude less than 1mm principal stress (<1 MPa) values much less than materials strength due to the small obtained displacements, two-way coupling may not be necessary

19. Interaction between unsteady flow and the elastic liner To be done: ◦Take into account the effect of the temperature ◦Develop a better tool for data transfer between the AVBP and KRATOS ◦Try different numerical scheme for LES ◦Try different element type for structural simulation (e.g. hexahedra)

20. Thank you for attention!