CDA Workshop Physical & Numerical Hydraulic Modelling. STAR-CCM+ Presentation

Transcription

1 CDA Workshop Physical & Numerical Hydraulic Modelling STAR-CCM+ Presentation

2 ENGINEERING SIMULATION CFD FEA

3 Mission Increase the competitiveness of companies through optimization of their product development using engineering simulation.

4 Lx Sim Services Engineering Simulation Outsourcing CAE-Intensive Product Design Training 4

5 Softwares CFD STAR-CCM+ AcuSolve FEA HyperMesh/RADIOSS HyperCrash DesignLife Optimization/DOE OptiStruct HyperStudy Process HyperForm HyperXtrude Moldex 3D MBD Post-Processing MotionSolve FieldView (CFD) 5

6 Sample Projects DFBI - CFD Trim and Drag Prediction on Ship Hull 6

7 Sample Projects Non-Linear FEA Prediction of Plastic Deformations on Frame 7

8 Sample Projects Heat Transfer / Solar Radiation / Porous Baffle CFD Automation of Solar Air Heater CFD 8

9 Outline STAR-CCM+ Overview and Capabilities Modeling and simulation procedure Limitations and known problems Case Study Questions 9

10 STAR-CCM+ Overview & Capabilities CD-adapco is the largest privately owned CFD company STAR-CCM+ GUI is java based, code is C++ Very flexible Customization possible Java macro system Finite volume method 10

11 STAR-CCM+ Overview & Capabilities General purpose CFD Multi-Physics CAD package Multiple meshing approaches Included post-processing Optimization 11

12 Complete Solution from CAD to Post 12

13 GUI Presentation Tree-based management Graphical window Output Properties 13

14 Tree-Based Management 14

15 CAD Preparation 3D-CAD Creating or modifying geometries Similar to any sketch based package Somewhat limited Exposing design variables Operation History Boolean Meshes Adds repeatability 15

16 Wrapper and Surface Repair Before After 16

17 Meshers Trimmed cell Polyhedral Embedded thin Tetrahedral Prism Thin mesher Refinement Volume Surfaces Edges 17

18 Physics Multiphase Lagrangian Eulerian VOF DEM Conjugated heat transfer Shell modeling Chemistry Combustion DARS Optimization solver Adjoint solver Electrochemistry Electromagnetism Overset meshes Radiation Aeroacoustics Batteries Casting DFBI FSI Solid stress Direct coupling 18

19 DAM Related Models VOF for multiphase - Cavitation - Particle transport and interaction DEM - Erosion model Moving parts, rotation, translation Multiple meshes approach 19

20 Cons No aeration by default or custom - Surface data not accessible during calculations Babysitting necessary Tweaking of interface solvers Mesh dependency - Large mesh - Long transient analysis 20

21 Case Study Modelling Method 21

22 Geometry Preparation Create top boundaries Operations to split in 3 regions Inlet Spillway Outlet 22

23 Meshing Trimmed cells Known surface Fast Mesh alignment Y+ between 10 and 150 targeted Refinement for interface Final mesh: Convergence not fully obtained Constraint in time and CPUs Use of relative to base size values 23

24 Mesh Hd - 2.7M Base size at 15m Medium transition in volume Surface 0.375m in inlet and outlet regions 0.15 m in spillway 24

25 Mesh Hd M Base size at 15m Medium transition in volume Surface 0.375m in inlet and outlet regions 0.15 m in spillway 25

26 Physics Model VOF multiphase Turbulent All y+ treatment Transient analysis Use of VOF wave to specify reservoir levels and inlets 26

27 Initial Conditions 27

28 Boundary Conditions Pressure VOFWave 28

29 Solver Set-Up and Convergence Multiple mesh approach to save computation time Time step 0.01s to 0.05s Settings available to increase accuracy for C >1 Stability issue 5 iterations per time step Presence of oscillations in solution flow rate Potential mesh vs timestep problem Choice made for time constraints vs accuracy 29

30 Case Study 1.5 X Design Head Q = 601 m 3 /s Maximum elevation at m 30

31 Velocity 31

32 Velocity 32

33 Relative Pressure 33

34 Relative Pressure 34

35 Froude Number 35

36 Turbulent Kinetic Energy Generating Air Entrainment 36

37 Air Entrainment at Surface Only Creation of field functions to find location air entrainment Exportation of the approximate surface Importation of the surface as a fluid region Interpolate functions on it Calculate aeration Attempted transport without success 37

38 Air Entrainment at Surface Only 38

39 Case Study 0.52 X Design Head Q = 115 m 3 /s 39

40 Velocity 40

41 Velocity 41

42 Relative Pressure 42

43 Relative Pressure 43

44 Froude Number 44

45 Turbulent Kinetic Energy Generating Air Entrainment 45

46 Air Entrainment at Surface Only 46

47 Questions?

48 Wrong BC??