Delving deeper into the benefits of co-simulation between LMS Amesim and STAR-CCM+, this study shows the results of coupling a 1D thermal and combustion model of an engine with a 3D Finite Elements mesh in STAR-CCM+. The aim is to acquire detailed information about localized temperatures and heat exchanges, which would enable engineers to locate hot-spots and design out areas where cooling is suboptimal.  Additionally, the co-simulation is run over the NEDC cycle, with a particular focus on the start-up phase. This made it possible to get clear insights into the engine’s thermal behavior in the transient between ambient to operating temperatures. For more information, please visit our website: siemens.com/plm/simcenter

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Page 1 Siemens PLM Software
LMS Amesim/STAR-CCM+
co-simulation
Heat transfer in an internal combustion engine
Unrestricted © Siemens AG 2017

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Page 2 Siemens PLM Software
Agenda
• Introduction to the product portfolio
• Motivations for this co-simulation
study
• Setup of the LMS Amesim model
• Setup of the STAR-CCM+ model
• Results of the LMS Amesim/STAR-
CCM+ co-simulation
• Going further

3. Unrestricted © Siemens AG 2017
Page 3 Siemens PLM Software
Simcenter™ Portfolio for Predictive Engineering Analytics
LMS Imagine.Lab
LMS Imagine.Lab Amesim
LMS
Imagine.Lab
System
Synthesis

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Page 4 Siemens PLM Software
Simcenter™ Portfolio for Predictive Engineering Analytics
STAR-CCM+
STAR-CCM+

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Simcenter™ Portfolio for Predictive Engineering Analytics
Cornerstones for a future-proof engineering approach
Cloud
Licensing
flexibility
Covering full range of
methods
Analytics, reporting &
exploration
Deployment flexibility
Openness &
Scalability
User experience
Industry &
engineering expertise
Systems approach
Collaboration &
workflow
Multidiscipline
& multiphysics
R
F
L
P
Controls
1D
3D
TEST
CFD

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Agenda
• Introduction to the product portfolio
• Motivations for this co-simulation
study
• Setup of the LMS Amesim model
• Setup of the STAR-CCM+ model
• Results of the LMS Amesim/STAR-
CCM+ co-simulation
• Going further

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Motivations for co-simulation
Engine cylinder head
Thermal reliability verification is carried out late in the development
process but is important for :
• cooling system definitions
• thermal stress calculations
• under-hood layout strategies
Cool but not overcool!
• overcooling reduces efficiency and increases emissions
• A valued approach improving both 1D and 3D CFD results
• Modelling of system interactions
• Realistic boundary conditions
• Possibility for multiple design iterations
Pain points:
Solution: co-simulation

8. Unrestricted © Siemens AG 2017
Page 8 Siemens PLM Software
Agenda
• Introduction to the product portfolio
• Motivations for this co-simulation
study
• Setup of the LMS Amesim model
• Setup of the STAR-CCM+ model
• Results of the LMS Amesim/STAR-
CCM+ co-simulation
• Going further

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LMS Amesim model for vehicle energy management (VEM)
Engine thermal management
Fuel economy and performance
Passenger comfort
Vehicle integration analysis
Cooling system analysis
LMS Amesim is a world leading platform for
physical simulation of mechatronics systems

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Parts of an internal combustion (IC) engine
Engine
block
External
block
+
Lower
block
Internal
block
GasketIntake side
+
Exhaust side
Camshaft
Cylinder
head

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LMS Amesim diagram of the IC engine thermal model
Thermal model of engine
Represents engine combustion and friction,
engine thermal mass, heat exchange with
underhood, water-jacket and oil-lubrication
system.
Representation of engine thermal masses
Engine split into thermal lumped masses:
• Engine block: inner block side, piston,
external block side, lower block
• Cylinder head: intake side, exhaust side,
cover with camshaft box
Engine thermal lumped masses (partial view)
Water
jacket
Intake
Camshaft + Engine cover
Exhaust
External
block
External
block
Lower block
Internal
block
Oil
cooler
Air
Combustion
chamber

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Co-simulation model
Water
jacket
Air
Camshaft + Engine cover
External
block
External
block
Lower block
Oil
cooler
Star-CCM +
3D
model
Internal block, piston, exhaust and intake sides
are simulated in STAR-CCM+.
Transverse view below, see next slides for full 3D perspective.
LMS Amesim model for co-simulation STAR-CCM+ model

13. Unrestricted © Siemens AG 2017
Page 13 Siemens PLM Software
Agenda
• Introduction to the product portfolio
• Motivations for this co-simulation
study
• Setup of the LMS Amesim model
• Setup of the STAR-CCM+ model
• Results of the LMS Amesim/STAR-
CCM+ co-simulation
• Going further

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• Based on an existing CAD model
• CAD cleaning and surface repair in
STAR-CCM+
STAR-CCM+ model
CAD
• 3D polyhedral unstructured mesh
• ≈100k cells for co-simulation case
Mesh
• Thermal properties extracted from LMS
Amesim model
• Segregated solid energy model
Physics
Exploded view of the CAD

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STAR-CCM+ mesh
Mesh generated for the engine and piston

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Page 16 Siemens PLM Software
Agenda
• Introduction to the product portfolio
• Motivations for this co-simulation
study
• Setup of the LMS Amesim model
• Setup of the STAR-CCM+ model
• Results of the LMS Amesim/STAR-
CCM+ co-simulation
• Going further

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Co-simulation model
Part in STAR-CCM+
Connected part in
LMS Amesim
Type
Internal block
External block 1
Water jacket 3
Lower block 2
Combustion gases 1
Intake side
External block 2
Water jacket 3
Camshaft 2
Air 3
Exhaust side
External block 2
Water jacket 3
Cam shaft 2
Air 3
Exhaust gases 1
Piston
Lower block 1
Combustion gases 1
Combustion chamber Combustion gases 1
Three types of inputs/outputs exchanged :
Type
name
Variable computed
by LMS Amesim
Variable computed
by STAR-CCM+
Type 1 Heat transfer (𝑊) Temperature (°𝐶)
Type 2 Temperature (°𝐶) Heat transfer (𝑊)
Type 3
Coolant temperature (°𝐶)
Heat coefficient (𝑊/𝑚𝑚2
°𝐶)
Temperature (°C)

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Co-simulation results
Unsteady simulation is done by following NEDC driving
cycle
Volume averaged temperature evolutions Temperature contours for the engine

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Co-simulation results
Complete detailed thermal behavior during start-up
phase in the engine and its different interfaces:
temperature and heat exchange prediction
Using 1D models, LMS Amesim represents
complete dynamics of the system including:
• Coolant flow rate inside the water jacket
• Vehicle fuel economy and performance in
interaction with the gearbox and the alternator
• Possibility to carry out multiple design studies
and to optimize heat transfer and temperature
distribution
Temperature contours for the pistons

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Co-simulation results
Co-simulation provides detailed 3D zoom on hot
parts of the engine
Temperature and heat transfer evolutions
for combustion chamber in LMS Amesim
Temperature contours for combustion chamber

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Co-simulation results
Heat rejection into water jacket in LMS Amesim
Water jacket

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Co-simulation results
Boundary heat flux across the cam interface
• Realistic boundary conditions
• Dynamic simulation
• Multi-physics model
Added value provided by
co-simulation
FMEP and fuel consumption evolutions in LMS Amesim
LMS Amesim STAR-CCM+
(*) FEMP: friction mean effective pressure

23. Unrestricted © Siemens AG 2017
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Agenda
• Introduction to the product portfolio
• Motivations for this co-simulation
study
• Setup of the LMS Amesim model
• Setup of the STAR-CCM+ model
• Results of the LMS Amesim/STAR-
CCM+ co-simulation
• Going further

24. Unrestricted © Siemens AG 2017
Page 24 Siemens PLM Software
STAR-CCM+/LMS Amesim co-simulation user guide in LMS
Amehelp

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Systems-Driven Product Development
Predictive Engineering Analytics
Role in Systems-Driven Product Development
Predictive Engineering AnalyticsSystem Mockup
Managed in PLM Context - Multi-Domain Traceability, Change and Configuration
TEST
Digital
Twin
1D
CFD
Exploration - Analytics - Reporting
3D

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3D SIMULATION
CFD SIMULATION
1D SIMULATION
From disconnected models and data …
Customer Usage data
Simulation data
Test data TEST MODELING
Historical data
CONTROLS

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…to a performance Digital Twin
3D SIMULATION
CFD SIMULATION
1D SIMULATION
Customer Usage data
Simulation data
Test data TEST MODELING
Historical data
CONTROLS

28. Realize innovation.
Karim NASSAR
Stéphane NEYRAT
LMS Amesim Platform
Romain GONARD
LMS Amesim Powertrain Subsytems
Girish BHANDARI
STAR-CCM+
Siemens Industry Software S.A.S.
Digital Factory Division
Product Lifecycle Management
Simulation & Test Solutions
DF PL STS CAE 1D