Investigation of the Effect of Flow on a Thin Orifice Plate by Fluid-Structure Interaction (FSI) Analysis

Transcription

1 Investigation of the Effect of Flow on a Thin Orifice Plate by Fluid-Structure Interaction (FSI) Analysis Dr.-Ing. Naseemuddin Dr.-Ing. M. Amir Siddiq Department of Mechanical Engineering

2 Outline 1. Introduction 2. Coupling Procedure 3. Methodology 4. Results 5. Conclusions 6. Future Plans 7 th International Bhurban Conference on Applied Siences and Technology, 2010

3 Introduction - Fluid-structure interaction problems require simultaneous application of computational fluid dynamics, computational structural mechanics and computational thermodynamics codes. - Two main approaches exist for the simulation of fluid-structure interaction problems: 1. Monolithic approach 2. Partitioned approach - Monolithic approach requires a code developed for simultaneous solution of flow and structure displacement equations. - Partition approach requires coupling of an existing flow solver and structural solver.

4 Introduction Typical Fluid-Structure Interaction Problems Metallic rod impacting and piercing on armor plate Vortex-induced vibration of a thin- walled structure Blood flow and heart behaviour By-pass operation

5 Aims & Objectives To build a procedure to simulate FSI problems by coupling a CFD and a CSM code. The effect of flow on the deformation characteristics of an orifice plate is investigated.

6 Coupling Procedure - In an FSI simulation, structure deforms due to forces caused by a fluid flow while the deformation changes the fluids boundary. - The deformation must be transferred to the CFD code, which corresponds to the quantities Nodal displacement. - Also, forces are sent from CFD to the structural code. Forces CFD code CSD code Displacements To Update Mesh

7 Coupling Procedure - Key issue in coupling and transferring the data is to ensure that data is exchanged at the desired time instance. Fluent Abaqus

8 Methodology Orifice in a Pipe Fluid Flow Direction Axisymmetric Model Orifice Plate Fluid Domain R100 mm 10 mm R50 mm 1000 mm

9 Methodology Axisymmetric Mesh of Orifice Plate Coupled Region - FE mesh consisted of 2000 bilinear 4-node axisymmetric quadrilateral elements. - The coupled region for which the nodal forces and nodal positions are transferred is shown.

10 Methodology Material Parameters - Two different materials Aluminium alloy 3003 and Titanium Alloy Ti6Al4V were tested. - Material parameters were indentified using inverse modelling approach Duan & Sheppard (2002) Simulation Stress (MPa) Stress (MPa) Experiment Simulation Plastic Strain Strain Aluminium Alloy AA-3003 Titanium Alloy Ti6Al4V

11 Results Titanium Alloy Ti6A4V - Contour plots of von Mises stress show that stresses in the region near the orifice are almost twice as high as in the other regions. - It is also found that Sparlat-Allmaras model induced higher stresses as compared to Laminar model. - Maximum Stress ( MPa) in the orifice plate due to fluid flow are much smaller than the yield stress (190 MPa). Laminar Model Spalart-Allmaras Model

12 Results Aluminium Alloy AA It is one of the many tough alloys in aluminium alloy family used in many aircraft assemblies. - It is 6-7 times softer than titanium alloys and less expensive. - Contour plots of von Mises stress show that Sparlat-Allmaras model induced higher stresses as compared to Laminar model. - Maximum Stress (0.067 MPa) in the orifice plate due to fluid flow are much smaller than the yield stress (190 MPa). Laminar Model Spalart-Allmaras Model

13 Results Deformation of Orifice Plate - Deformation in both Ti6A4V and AA3003 was high for Spalart-Allmaras Model. - Due to the fluid flow through the orifice the regions in the vicinity of the orifice show higher amount of deflection as compared to the regions which are near the region that is fixed to the pipe. - This also explains the higher stresses in those regions as discussed before. Spalart-Allmaras Model (AA3003) Spalart-Allmaras Model (Ti6A4V)

14 Conclusions - A coupled fluid-structure analysis technique was presented. - An example of an orifice plate fitted in a pipe with air flowing through it was studied using coupled FSI approach. - It was found that fluid flow behaviour does effect the structural response of the orifice plate. - Two different materials (Ti6A4V and AA-3003) were explored in this work. - Stressed induced in both the materials show similar values, however for softer AA3003 the deformation was higher than of Ti6A4V. - Both the materials were found to be suitable for the current application.

15 Outlook - It is necessary to perform 3D computations which are in process. - To incorporate the damage and erosion models in the CSM code to model the wall and orifice thinning effects under severe flow conditions. Planned in the next phase. - To perform dynamic simulations, such as of wind turning rotation due to wind. (On going work)