LMS Amesim/STAR-CCM+ co-simulation – Heat transfer in an internal combustion engine

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LMS Amesim/STAR-CCM+

co-simulationHeat transfer in an internal combustion engine




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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STAR-CCM+

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Agenda



study




CCM+ co-simulation

• Going further



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



Agenda



study




CCM+ co-simulation

• Going further



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



Parts of an internal combustion (IC) engine

Engine

blockExternal

block

+

Lower

block

Internal

block

GasketIntake side

+

Exhaust side

Camshaft

Cylinder

head



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

jacketIntake

Camshaft + Engine cover

Exhaust

External

block

External

block

Lower block

Internal

block

Oil

cooler

Air

Combustion

chamber



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



Agenda



study




CCM+ co-simulation

• Going further



• 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



STAR-CCM+ mesh

Mesh generated for the engine and piston



Agenda



study




CCM+ co-simulation

• Going further



Co-simulation model

Part in STAR-CCM+Connected part in

LMS AmesimType

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

PistonLower 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 3Coolant temperature (°𝐶)

Heat coefficient (𝑊/𝑚𝑚2°𝐶)Temperature (°C)



Co-simulation results

Unsteady simulation is done by following NEDC driving

cycle

Volume averaged temperature evolutions Temperature contours for the engine




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

distributionTemperature contours for the pistons




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




Heat rejection into water jacket in LMS Amesim

Water jacket




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



Agenda



study




CCM+ co-simulation

• Going further



STAR-CCM+/LMS Amesim co-simulation user guide in LMS

Amehelp



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Predictive Engineering Analytics

Role in Systems-Driven Product Development

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From disconnected models and data …

Customer Usage data

Simulation data

Test data TEST MODELING

Historical data

CONTROLS



…to a performance Digital Twin

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CFD SIMULATION

1D SIMULATION

Customer Usage data

Simulation data

Test data TEST MODELING

Historical data

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Realize innovation.

Karim NASSAR

Stéphane NEYRATLMS Amesim Platform

Romain GONARDLMS Amesim Powertrain Subsytems

Girish BHANDARISTAR-CCM+

Siemens Industry Software S.A.S.

Digital Factory Division

Product Lifecycle Management

Simulation & Test Solutions

DF PL STS CAE 1D

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