Numerical investigations of fluid structure interaction between unsteady flow\ud
and vibrating liner in a combustion chamber are undertaken. The computational study consist of two approaches. Firstly, a partioned procedure consists of coupling the LES code AVBP for combustion modelling with the FEM code CaluliX for structural dynamic analysis. The CFD code CFX together with the FEM Ansys package are then used.\ud
Results of unsteady fluid structure interaction applied to combustion system are presented and compare well with experimental results

Cooper, R.K.

Khatir, Z.

Kok, J.B.W.

Pozarlik, A.K.

Watterson, J.W.

English

Numerical investigations of fluid structure interaction between unsteady flow and vibrating liner in a combustion chamber are undertaken. The computational study consist of two approaches. Firstly, a partioned procedure consists of coupling the LES code AVBP for combustion modelling with the FEM code CaluliX for structural dynamic analysis. The CFD code CFX together with the FEM Ansys package are then used. Results of unsteady fluid structure interaction applied to combustion system are presented and compare well with experimental results

Pozarlik, Artur Krzysztof

Kok, Jacobus B.W.

University of Twente Research Information

Int. Conf. on Computational Methods for Coupled Problems in Science and EngineeringCOUPLED PROBLEMS 2007M. Papadrakakis, E. Oñate and B. Schrefler (Eds)c©CIMNE, Barcelona, 2007NUMERICAL INVESTIGATIONS OF FLUID STRUCTUREINTERACTION BETWEEN UNSTEADY FLOW ANDVIBRATING LINER IN A COMBUSTION CHAMBERZ. KHATIR∗1, A.K. POZARLIK†, J.B.W. KOK†, R.K. COOPER∗ and J.W.WATTERSON∗∗School of Mechanical and Aerospace Engineering, Queen’s University BelfastAshby Building, Stranmillis RoadBelfast BT9 5AH, Northern Ireland, U.K.e-mail: z.khatir@qub.ac.uk/zkhatir@hotmail.com†Laboratory of Thermal Engineering, University of TwenteP.O. Box 217, 7500 AE Enschede, The Netherlandse-mail: a.k.pozarlik@utwente.nlKey words: Coupled Computational Fluid Dynamics-Computational Structural Dy-namics, Combustion Application, Computational Investigation.Abstract. Numerical investigations of fluid structure interaction between unsteady flowand vibrating liner in a combustion chamber are undertaken. The computational studyconsist of two approaches. Firstly, a partioned procedure consists of coupling the LEScode AVBP for combustion modelling with the FEM code CaluliX for structural dynamicanalysis. The CFD code CFX together with the FEM Ansys package are then used.Results of unsteady fluid structure interaction applied to combustion system are presentedand compare well with experimental results.1 INTRODUCTIONThe ability to predict the stability of a given burner is the centre of many studies whichcan be experimental [1, 2] or numerical [3, 4, 5]. The present study is towards betterunderstanding of transient combustion and its coupling with combustion wall vibration.Motivated by the above concerns, numerical investigations on the coupling betweenCFD and CSD are undertaken. After specifying the experimental set-up, the next Sectionwill be devoted to the computational procedures. Two numerical methods are presented.One consists of a partioned scheme for coupling the CFD research code AVBP [6] withthe FEM code CaluliX [7]. The other approach uses the following commercial codes fromANSYS: CFX-10 for the CFD modelling and the Ansys FEM for CSD analysis [8]. Finally,Section 3 presents the results of numerical computations which contribute to validate theproposed investigations by comparison with experimental data.1Correspondence: Rock Deformation Research, School of Earth Sciences, University of Leeds, Leeds LS2 9JT, U.K. Email: zkhatir@hotmail.com1Z. Khatir, A.K. Pozarlik, J.B.W. Kok, R.K. Cooper and J.W. Watterson2 EXPERIMENTAL AND COMPUTATIONAL SPECIFICATIONS2.1 Experimental set-upFigure 1: (Left) Experimental setup; (Right) Schematic of the combustion chamber geometry.In order to measure vibration of the liner during the combustion process, the setup isequipped with the system of windows as shown in Figure 1. The part of the liner placeddirectly behind this transparent system is much thinner than the other liner elements.This flexible section responds more strongly to transient changes of the pressure insidethe chamber during the transient combustion. The vibrations of the liner are measuredby laser Doppler vibrometer. The characteristics of the flexible liner and the operatingconditions during combustion experiment are depicted in Tables 1 and 2 respectively.Property Value Property ValueLength L 0.400 m Young’s modulus E 138 GPaWidth W 0.150 m Poisson’s ration νs 0.3Thickness t 0.0015 m Density ρs 7844 kg/m3Table 1: Dimensions and material properties of the flexible structural liner.Power Absolute Air factor Total mass flow Air preheating[kW] pressure [bar] [-] [g/s] temperature [K]125 1.5 1.8 75.53 573Table 2: Operating conditions during combustion experiment.2.2 Computational models2.2.1 Coupled AVBP-CaluliX modellingA LES fully compressible explicit code is used to solve the multi-species Navier-Stokesequations on hybrid grids. Subgrid stresses are described by the classical Smagorinskymodel [6]. The flame/turbulence interaction is modelled by the Dynamic Thickened Flame(DTF) model which accounts for both mixing and combustion. Unsteady calculations areperformed following operating conditions in Table 2 ([3]). The pressure loads from AVBPare used as inputs in the FEM code CaluliX. Care is taken to accurately transfer thepressure loads from CFD to CSD as a structured mesh is used for CSD using a volumespline interpolation [4, 5].2Z. Khatir, A.K. Pozarlik, J.B.W. Kok, R.K. Cooper and J.W. Watterson2.2.2 Coupled CFX-Ansys modellingURANS is the numerical approach used for combustion flow. A quarter of the chamberis computed to save computational time. The reacting flow is solved using an EddyDissipation and Finite Rate Chemistry combustion models with k-ε turbulence modelas available in CFX. The mass fraction ratio of the fuel to air ratio in the inlet flowis pulsated with frequency 300 Hz with amplitude equal to 8.5%. Simultaneously, thetransient structural deformations of the wall are computed as in Figure 2. As a result ofthe modular liner design no significant thermal stresses are generated. Calculations areperformed with material properties adequate to temperature equal to 760◦C. Exchangeof information between CFX and Ansys is made possible by the MFX code. Fixed support 4 Fixed support 3 Fixed support 2 Fixed support 1 CFX Pressure resultsFigure 2: Boundary conditions used for solid model.3 RESULTSFigure 3: Isosurface of pressure forces at time t = 0.885 s: (Left) CFD AVBP forces; (Right) CSDCaluliX forces after transfer using volume spline interpolation [4, 5].The isosurface of AVBP and CalculiX forces on the flexible liner is plotted in Figure 3at t = 0.885 s. The distribution for both cases is very similar. The sum of the CFDand CSD forces on the flexible liner is identical, as are the 1st and 2nd moments. Thisconfirms an accurate data transfer between CFD and CSD. Results predicted by numericalcalculations show good agreement with experiment as seen in Figures 4– 5.4 CONCLUSIONS1. Computational investigations of coupled CFD-CSD applied to combustion systemhave been performed, and show good agreement with experiment.2. Further investigations are still being undertaken to provide a better understandingof FSI in combustion systems.3Z. Khatir, A.K. Pozarlik, J.B.W. Kok, R.K. Cooper and J.W. Watterson0 2 4 6 8 10 12 14 16 18 20−600−400−2000200400600time (ms)pressure (Pa)Figure 4: Pressure fluctuations on flexible liner: (——) Experiment; (- - - -) AVBP and (-.-.-.-.)CFX numerical simulations.0 2 4 6 8 10 12 14 16 18 20−0.1−0.0500.050.1time (ms)velocity (m.s−1)Figure 5: Vibrating liner’s velocity: (——) Experiment; (- - - -) Coupled AVBP-CalculiX and(-.-.-.-.) Coupled CFX-Ansys computations.ACKNOWLEDGEMENTS• EC Marie Curie RTN project FLUISTCOM, contract MRTN-CT-2003-504183.• A.X. Sengissen, P. Mauro: CERFACS, Toulouse, France.• R. Huls: University of Twente, Enschede, The Netherlands.REFERENCES[1] Huls R. Acousto-Elastic Interaction in Combustion Chambers, PhD thesis, University ofTwente, Enschede,The Netherlands, ISBN: 90-365-2336-2, 2006.[2] Pozarlik A.K. and Kok J.B.W. The interaction of combustion pressure oscillation andliner vibrations, 13th International Congress on Sound and Vibration (ICSV13), Vienna,Austria, July 2-6, 2006.[3] Sengissen A.X. Simulation aux grandes échelles des instabilités de combustion: vers lecouplage fluid/structure, PhD thesis, TH/CFD/06/30, INP Toulouse, France, 2006.[4] Khatir Z. Fluid structure interaction computation with application to combustion sys-tem, European Marie Curie RTN FLUISTCOM Workshop on Fluid Structure Interaction- Numerical Aspects and Coupling Software with Applications, Queen’s University Belfast,Belfast, UK, January 25-26, 2007.[5] Khatir Z. Computation of fluid structure interaction with application to three-dimensionalcombustion System, 4th International Conference on Computational Fluid Dynamics (IC-CFD4), Ghent - Belgium, July 10-14, 2006.[6] The AVBP code: A parallel CFD code for reactive unsteady flow simulations on hybridgrids. http://www.cerfacs.fr/cfd/avbp.html[7] CALCULIX: A Free Software - Three-Dimensional Structural Finite Element Program.http://www.calculix.de[8] Ansys HTML Online Documentation, Ansys 10.0, Ansys Inc. 2005.4

Numerical investigation of fluid structure interaction between unsteady flow and vibrating liner in a combustion chamber

Acousto-Elastic Interaction in Combustion Chambers,

CALCULIX: A Free Software - Three-Dimensional Structural Finite Element Program.

Computation of ﬂuid structure interaction with application to three-dimensional combustion System,

Fluid structure interaction computation with application to combustion system,

Simulation aux grandes ´ echelles des instabilit´ es de combustion: vers le couplage ﬂuid/structure,

The AVBP code: A parallel CFD code for reactive unsteady ﬂow simulations on hybrid grids.

The interaction of combustion pressure oscillation and liner vibrations,

http://purl.utwente.nl/publications/81717

Numerical investigation of fluid structure interaction between unsteady flow and vibrating liner in a combustion chamber

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