Spread out – distribute your co-simulations, co-simulating LMS Amesim with STAR-CCM+ to analyze a servovalve

Realize innovation.Unrestricted © Siemens AG 2017

Spread out – distribute your

co-simulationsCo-simulating LMS Amesim with STAR-CCM+

to analyze a servovalve LMS Imagine.Lab Amesim™

A world leading platform for physical

simulation of mechatronic systems

Page 2 Siemens PLM Software

Unrestricted © Siemens AG 2017


Table of contents

• Introduction to the product portfolio

• Motivation for this co-simulation study

• Setup of the 1D LMS Amesim model

• Setup of the 3D STAR-CCM+ model

• Results of the LMS Amesim/STAR-CCM+ co-simulation

• Going further




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Table of contents


• Motivations for this co-simulation study




• Going further




Presentation of the electro-hydraulic servovalve

• This study demonstrates the possibility to solve

dynamic complex hydraulic problems with 3D CFD

detailed flapper valve representation

• LMS Amesim/STAR-CCM+ co-simulation to model the

behavior of such complex systems with overset mesh

• Better prediction of the pressure gradient depending on

the flapper lift, so the force balance is more accurate

• The 1D model of the servovalve without co-simulation is

available in LMS Amesim.

STAR-CCM+ has a dedicated user interface to connect to LMS Imagine.Lab Amesim

that makes the co-simulation process easy to set-up.

Servovalve (MOOG illustration)

Motivations




3D CFD flappers in co-simulation with the 1D servolvalve model

Two 3D CFD flapper valves with a complete LMS Amesim model

• Calculates the flow rate from the pressure

boundary conditions and position of the

flappers

• Integrates the pressure gradient on the flapper

to estimate the hydrodynamic force

• Represents the entire servovalve

• Includes a magnetic torque motor acting on a

mechanical armature

• Controls a spool valve thanks to a hydraulic

circuit

• Provides the boundary conditions of the valves

and the displacement of the two flappers

LMS Amesim

STAR-CCM+

LMS Amesim




Table of contents






• Going further




Operating principles of the nozzle-flapper type servo-valve

• This servovalve is an electronically operated 2-stage

device. It’s typically used in the aerospace and automotive

industries

• These valves are primarily used for closed loop control of

position, force and velocity. They offer high performance for

amplification and response time

• These valves consist of two stages:

• the 1st stage has a magnetic torque motor and is of

flapper/nozzle type design

• the 2nd stage has a precision ground 4-way control spool

and a feedback system which may be either mechanical

or electrical

Servovalve (MOOG illustration)




Ready-to-use template demo in LMS Amesim

A ready-to-use model is available in LMS Amesim to:

• analyze the system step response

• compute the leakage of the valve second stage

• compute the valve pressure characteristic at zero flow

• identify the eigenvalue of the flexure tube

Complete model of a flow control servovalve Step responses for various signal inputs (% of rated current)

LMS Amesim




Next step is to get more details for the flapper nozzles

LMS Amesim

LMS Amesim

LMS Amesim

STAR-CCM+

STAR-CCM+

The two flapper nozzles considered in 1D will be

converted into two CFD 3D STAR-CCM+ models

+




Table of contents






• Going further




Meshing of the 3D STAR-CCM+ model domain

• The volume meshes are generated by the

Automatic 3D polyhedral mesher

• Two meshes are created:

• One mesh which covers the entire domain

• Another mesh surrounds the flapper, and

translates according to the flapper motion

• Overset mesh technology in STAR-CCM+

interpolates both meshes together to create a

single computational mesh of the fluid domain

• The overset interpolation is executed with each

time step, and allows extreme motions of the

flapper to be modelled in STAR-CCM+ Resulting Overset meshes near end stop

Moving mesh around flapper shown in purple

Stationary background mesh shown in green

Moving mesh is updated

during simulation




Setup of the co-simulation in LMS Amesim

Method

The benefit of this simulation consists in modeling two flapper valves in CFD at the same time. It can be done

in two different simulations, that are run on different machines.

Here one of them is run locally and the other on a Linux machine on the network.

Each flapper valve is modeled in a super-component.

Each super-component is composed of the model and a TCP/IP communication block with a unique

communication port.

Supercomponent #1 Supercomponent #2




Table of contents






• Going further




Multiple STAR-CCM+ simulations coupled to one LMS Amesim

model

Distant STAR-CCM+

simulation on a

Linux machine on

the network

Local STAR-CCM+

simulation on the

local computer

LMS Amesim run locally on the local

computer

Strategy used to couple the multiple simulations

LMS Amesim




Run and results of the LMS Amesim / STAR-CCM+ co-simulation

• A positive current signal step is used to control the

torque motor

• The torque motor acts on the flexure tube of the

armature to control the displacement of the

flappers

• The forces generated by the end-stops are

computed in LMS Amesim

• The output flow rate reaches the set point

value defined by the input command

• Valve dynamics is fast w.r.t the large flow rate

Output flow rateDisplacement of the two flappers

Results in LMS Amesim




Run and results of the LMS Amesim / STAR-CCM+ co-simulation

Simulation aspects

• Simultaneous simulations of the two flapper valves

running in parallel, coupled with a unique detailed

LMS Amesim model

• The model requires a small time-step for the solver

when the valve is almost closed

• Co-simulation adds information about the pressure

gradient and the fluid velocity in the two flapper

valves

Results in STAR-CCM+

Pressure

Velocity




Table of contents






• Going further




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

Amehelp




Co-simulation: LMS Amesim (local Windows), STAR-CCM+

(clustered Linux)

HPC

CO-SIMULATION

1D or 3D CFD

simulation

Engineer

1D outputs as inputs into 3D CFD

3D CFD outputs as inputs into 1D

LMS Amesim is set-up on a local Windows PC,

and STAR-CCM+ is configured on a Linux cluster

High Performance

Computing (HPC)

LMS Amesim




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From disconnected models and data …

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…to a performance Digital Twin

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Customer Usage data

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Historical data




Contact

Karim NASSAR & Stéphane NEYRAT | LMS Amesim Platform

Joe OSMAN | STAR-CCM+

Siemens Industry Software S.A.S.

Digital Factory Division

Product Lifecycle Management

Simulation & Test Solutions

DF PL STS CAE 1D | CD-adapco

siemens.com

https://www.plm.automation.siemens.com/en/products/simcenter/index.shtml

Technology

Spread out – distribute your co-simulations, co-simulating LMS Amesim with STAR-CCM+ to analyze a servovalve