3DS.COM © Dassault Systèmes | Confidential Information | 4/9/2015 | ref.: 3DS_Document_2014 FLOW TOPOLOGY OPTIMIZATION OF A TURBO CHARGERS INFLOW DUCT Dr. Jens Iseler [email protected] 17.03.2015
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2014 FLOW TOPOLOGY
OPTIMIZATION OF A TURBO
CHARGERS INFLOW DUCT
Dr. Jens Iseler
17.03.2015
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2014 1 Problem Description
2 Method Description
3 Topology Optimization
4 Shape Optimization
5 Summary
Overview
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Problem Description
Provide compressor inflow duct with:
low pressure loss
increased flow uniformity
Procedure:
Topology optimization (draft design)
Reconstruction via CAD tool
Shape optimization
Existing inflow duct
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Applied Workflow
Topology optimization based on
optimality criteria
Reconstruction of obtained design
Shape optimization based on
adjoint solution
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Topology Optimization For CFD ProblemsOptimization problem is based on the
(meshed) available design space
initi
al d
esig
n
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Optimization problem is based on the
(meshed) available design space
Geometric variation is achieved by
sedimenting individual cells
initi
al d
esig
npo
ssib
le v
aria
nts
Topology Optimization For CFD Problems
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Optimization problem is based on the
(meshed) available design space
Geometric variation is achieved by
sedimenting individual cells
An individual design proposal can be
derived based on the collectivity of all free
(= non-sedimented) cells
Optimization represents coupled run. New
design available after 1 single run
initi
al d
esig
npo
ssib
le v
aria
nts
Topology Optimization For CFD Problems
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Tosca Fluid Optimization – Sedimentation Process
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Tosca Fluid Setup
Optimization Setup
Optimization approach: Optimality criteria
Elimination of recirculation zones
Defined iteration number: 20000
Mesh with 400 K elements
Simulation time: 20.0 hrs. with 4 CPU Initial geometry Design space vs.
existing design
Reference streamline
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Tosca Fluid Setup
Optimization Setup
Optimization approach: Optimality criteria
Elimination of recirculation zones
Defined iteration number: 20000
Mesh with 400 K elements
Simulation time: 20.0 hrs. with 4 CPU
Postprocessing
Extraction of areas with low velocities
Smoothing of the remaining geometry
Initial geometry Design space vs.
existing design
Reference streamline
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Tosca Fluid Design
Fully 3D design proposal
Cross section area bigger compared to existing design
Section plane
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Tosca Fluid Design
Fully 3D design proposal
Cross section area bigger compared to existing design
Result: Overall smaller velocities reduced pressure
drop likely
Section plane
Tosca Fluid design
Existing design
Velocity distribution
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Why?
Obtained design fully 3D
Manufacturing constraints must be considered
Design may contain rough areas
Reconstruction of Optimized Design
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Why?
Obtained design fully 3D
Manufacturing constraints must be considered
Design may contain rough areas
Strategy:
Maintain global shape of optimized design
Adjust shape locally (geometric constraints, spikes)
Reconstruction of Optimized Design
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Reconstruction of Optimized Design
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Reconstruction of Optimized Design
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Reconstruction of Optimized Design
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Reconstruction of Optimized Design
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Reconstruction of Optimized Design
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Flow Performance – Existing Design
Cone outlet plane
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Flow Performance – Optimized Design
Cone outlet plane
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Comparison Optimized Design – Existing Design Total pressure loss + uniformity
Optimized
design
Existing design
Total pressure
loss
426 Pa 495 Pa
Uniformity 0.982 0.978
Optimized design Existing design
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Shape Optimization With STAR-CCM+®
Idea:
Topology optimization delivers design based on
empiric optimality criteria
Further potential of improvement by usage of
gradient method
Efficient solving of gradients/sensitivities by means
of adjoint solution
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Shape Optimization With STAR-CCM+ Idea:
Topology optimization delivers design based on
empiric optimality criteria
Further potential of improvement by usage of
gradient method
Efficient solving of gradients/sensitivities by means
of adjoint solution
Strategy:
Define a closed loop including adjoint solver and
morphing module
Deformation dependent on computed sensitivities
Initial geometry = topology optimized design
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Shape Optimization With STAR-CCM+
Pressure drop: -45%
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Shape Optimization With STAR-CCM+ Objective function: Pressure drop
Creation of morphing boxes via Lattice
Overall 500 control points
STAR-CCM+ macro:
Calls primal solver, adjoint solver and morpher for
predefined number of loops
Considers maximum allowed deformation through
scaling of sensitivities
Gradual adjustment of scale factor dependent on
behavior of objective function
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Shape Optimization With STAR-CCM+
Topology
optimization
Shape
optimization
Total pressure
loss
426 Pa 389 Pa
Uniformity 0.982 0.983
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Shape Optimization With STAR-CCM+
Topology optimized
design
Shape optimized
design
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Workflow Based on Non-Parametric Optimization
Topology optimization based on optimality criteria
Reconstruction of obtained design
Shape optimization based on adjoint solution
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Summary Objective: Duct Flow with low pressure drop and increased uniformity
Tosca Fluid topology optimization based on available design space
Reconstructed optimized design reveals a significant total pressure loss
reduction (-14%) and increased uniformity (from 0.978 to 0.982)
STAR-CCM+ macro developed to run primal solver, adjoint solver and morpher
for predefined number of cycles. Considers maximum allowed deformation
through scaling of sensitivities
STAR-CCM+ shape optimization based on adjoint solution led to further
reduction of the total pressure loss (-7.5%) and slightly increased uniformity
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Shape Optimization With STAR-CCM+
Pressure drop: -45%
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Shape Optimization With STAR-CCM+
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Shape Optimization With STAR-CCM+
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CFD setup
Topology-Optimization
Solver: STAR-CCM+ 9.06.009
Physics:
Incompressible
Steady
k-ε turbulence, All y+
Boundary conditions:
Inlet: Stagnation inlet
Outlet: Mass flow inlet
Verification
Solver: STAR-CCM+ 9.06.009
Physics:
Incompressible
Steady
k-ε turbulence, All y+
Boundary conditions:
Inlet: Massflow inlet
Outlet: Pressure outlet
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CFD setup
Topology-Optimization
Solver: STAR-CCM+ 9.06.009
Physics:
Incompressible
Steady
k-ε turbulence, All y+
Boundary conditions:
Inlet: Stagnation inlet
Outlet: Mass flow inlet
Verification
Solver: STAR-CCM+ 9.06.009
Physics:
Incompressible
Steady
k-ε turbulence, All y+
Boundary conditions:
Inlet: Massflow inlet
Outlet: Pressure outlet