COMPASS All-Hands Meeting,COMPASS All-Hands Meeting,

FNAL, Sept. 17-18, 2007FNAL, Sept. 17-18, 2007

Accelerator Prototyping Accelerator Prototyping Through Multi-physics Through Multi-physics AnalysisAnalysis

Volkan Akcelik, Lie-Quan Lee, Ernesto Prudencio,

Cho Ng, Zenghai Li, Kwok Ko

Advanced Computations DepartmentStanford Linear Accelerator Center

Work supported by DOE ASCR, BES & HEP Divisions under contract DE-AC02-76SF00515

2

Multi-physics Analysis for Multi-physics Analysis for Accelerator ComponentsAccelerator Components

Virtual prototyping through computing Thermal and mechanical analysis as important as

EM analysis EM heating, Thermal radiation, Lorentz force detuning,

Mechanical stress Augmented by additional physics

particle effects including emittance and multipacting Nonlinear and transit effects in superconducting cavity

design Accurate and reliable multi-physics simulation

requires large-scale parallel computing: TEM3P

3

TEM3P: Multi-Physics TEM3P: Multi-Physics Analysis Analysis

CAD Model

EM Analysis

Thermal Analysis

Mechanical Analysis

Finite element based with higher-order basis functions Natural choice: FEM originated

from structural analysis! Use the same software

infrastructure as Omega3P Reuse solvers framework Mesh data structures and

format Parallel

4

TEM3P for LCLS RF GunTEM3P for LCLS RF Gun

EM DomainThermal/Mechanical Domain

Benchmark TEM3P against ANSYS

CAD Model (courtesy of Eric Jongewaard)

5

RF Gun EM analysisRF Gun EM analysis

The second mode is operating mode

Its magnetic field on the cavity inner surface generates heating!

1st mode 2.8411 GHz

2nd mode 2.8561 GHz

6

Mesh for Thermal/Mechanical Mesh for Thermal/Mechanical analysisanalysis

Mesh: 0.6 million nodes.Materials: Copper + Stainless steelThermal analysis: 7 cooling channels EM Heating

7

Parameters for Thermal Parameters for Thermal AnalysisAnalysis

TEM3P: cooling channels modelled as Robin BC 7 cooling channels

specific temperatures and film coefficients Thermal load from EM power loss (4000 Watt)

EM Heating BC Thermal conductivity for copper 391 Thermal conductivity for stainless steel 16.2 Other surfaces modelled as homogeneous

Neumann BC

8

Thermal Analysis Thermal Analysis loaded with EM Heatingloaded with EM Heating

ANSYS TEM3PMaximal Temperature 49.96 C Maximal Temperature 49.82 C

Temperature Distribution

9

Mechanical Analysis Mechanical Analysis with Thermal Loadwith Thermal Load

ANSYS TEM3PMaximal displacement: 37.10 mMaximal displacement: 36.99 m

Future work: compute stress and shifted frequency due to geometry change

10

Multi-physics Analysis for Multi-physics Analysis for SRF Cavities and SRF Cavities and CryomodulesCryomodules Thermal behaviors near

superconducting region are highly nonlinear

SRF Cavity wall is very thin Anisotropic high-order

mesh will reduce significant amount of computing

Working with RPI/ITAPS