Fully Automatic In-cylinder Workflow UsingHEEDS / es-ice / STAR-CD

Simon Fischer – Senior ICE Application Support Engineer – CD-adapco Nuremberg Office

Gerald Schmidt – Director/Powertrain - CD-adapco New York Office

Introduction and Enabling Technology

Workflow and HEEDS Portal Description– Underlying Scripts

– Data Preparation

– CAD Modification

– Surface Preparation

– Automatic Meshing

– Physical / Numerical Model Setup

– Running STAR-CD

– Postprocessing

Demo Study: The Optimized Race Engine

Further Examples of Successful In-Cylinder and Related Studies

Outline

HEEDS is a well established MDX tool applicable to many CFD problems– Red Cedar Technology recently developed dedicated HEEDS portals

for pro-STAR, es-ice, and STAR-CD making it easier to define workflows for in-cylinder simulation

The key enablers of MDX for in-cylinder simulation are robust moving mesh technology and high fidelity physics capability– A major focus of es-ice development has been to provide a fully

automated robust meshing technology with minimum user intervention

– STAR-CD provides a big library of state-of the art in-cylinder relevant physics models (from multi-phase to combustion chemistry)

This presentation shows the possibility of in-cylinder simulation using a fully automatic HEEDS/es-ice/STAR-CD workflow

Introduction and Enabling Technology

Generic scripted process of STAR-CCM+ surface preparation, es-ice fully automatic meshing and model setup, pro-STAR model setup, STAR-CD cluster submit, and es-ice/pro-STAR postprocessing

Minimum User Interaction to Prepare Input Data

Process, parameter setting/variation, io-operations, postprocessing managed by HEEDS MDO employing the STAR-CCM+ portal and recent STAR-CD, es-ice, and pro-STAR portals

Meshing and physics parameters and results output managed through HEEDS parameter tagging

Workflow Description

Generic scripted process of STAR-CCM+ surface preparation, es-ice fully automatic meshing and model setup, pro-STAR model setup, STAR-CD cluster submit, and es-ice/pro-STAR postprocessing

Workflow Description: Underlying Scripts

Minimum User Interaction to Prepare Input Data– Surface preparation in STAR-CCM+ (GeometryPreparation.sim)(Geometry from CAD-Modeller, Imported CAD, Discretized Surface)– Naming convention– Orientation, Scaling, Valve and Piston position– CAD/surface repair (clean CAD, waterproof surface)

Deliver Boundary Conditions in appropriately formatted files

Workflow Description: Data Preparation

Process, parameter setting/variation, io-operations, postprocessing managed by HEEDS MDO employing the STAR-CCM+ portal and recent STAR-CD, es-ice, and pro-STAR portals

Meshing and physics parameters and results output managed through HEEDS parameter tagging

Workflow Description: HEEDS Process

Workflow Details: CAD Modification

Optional:Direct CAD Design Parameter (if exposed)access through HEEDS‘sdedicated Portals:• here STAR-CCM+ Portal• Also available:

NX, CATIA, CREO,...

ParametrizedSTAR-CCM+ Geometry Preparation sim-File

Workflow Details: Surface Preparation

• Input STAR-CCM+ Geometry Preparation sim-File• Automated Parts Based STAR-CCM+Surface Remesh using es-ice best practices • (Optional) Automated Additional Static Part Volume Meshing• Export of es-ice -appropriate .dbs Surface fileand additional ccm volume meshes

• Underlying meshing script featuring latest es-ice automatic meshing technology and best practice

• User input is limited to a minimum of mesh parameters, e.g. mesh base size, prism layer thickness, etc.

• No expert knowledge of es-ice template mesh generation is necessary

• Yet scripted meshing is open source and fully customizable for expert users

Workflow Details: Automatic Meshing

Workflow Details: Automatic Meshing

es-ice scripted meshing HEEDS portal to automatically

• Script allowing for Automatic Parameter Tagging to expose parameters to a HEEDS design study (e.g. Make a mesh study)

tag parameters

e.g. Make a mesh study

Workflow Details: Automatic Meshing

High quality moving mesh with NO user intervention

Workflow Details: es-ice Model Setup

es-ice scripted model setup• Boundary conditions• Initial conditions• Predefined best practice

setup scripts • Cold flow• Mixture preparation• Combustion study

• All scripts open source and fully customizable

• All scripts allowing for Automatic Parameter Tagging to expose parameters to a HEEDS design study

Workflow Details: pro-STAR Model Setup

pro-STAR scripted model setup• Liquid phase setup for

injector boundary conditions, liquid film, and spray physics

• Predefined best practice setup scripts • Cold flow• Mixture preparation• Combustion study

• All scripts open source and fully customizable

• All scripts allowing for Automatic Parameter Tagging to expose parameters to a HEEDS design study

Workflow Details: Running STAR-CD

Scripted cluster submit including all file handling (copying forth and back), monitoring jobs, etc., handling multiple computational resources

Workflow Details: Postprocessing

es-ice postprocessing plugin HEEDS portal to automatically tag results

Automatic Parameter Tagging to expose Results to HEEDS

Enablingpostprocessing in HEEDS for an MDX study

Workflow Details: Postprocessing

• Scripted call of pro-STAR engine animation script

Workflow Details: Postprocessing

Fully embedded postprocessing in HEEDS

Workflow Details: Project Management

Fully integrated management of • Processes (Cold Flow,

MixturePreparation, Combustion)

and related • Design Exploration Studies (e.g.

Single Baseline, Mesh Sensitivity, Geometry Optimization, ...)

within the HEEDS Environment

The sample study features:

Automatic CAD modification through STAR-CCM+ CAD modeler

Automatic generation of moving mesh for intake and compression stroke for each design using es-ice

Lagrangian spray, wall impingement, liquid film

Tracking of fresh air, fuel, and residual through active species

Turbulent flow field assessment with STAR-CD

Evaluation of engine data

Optimization of design through HEEDS

Users touch neither the es-ice nor the pro-STAR GUI, leaving required expertise to a minimum

Demo Study: An Optimized Race Engine

Design parameters: Piston bowl shape and injector direction

Goal: Maximize fuel and maximize turbulence at the ignition point

Demo Study: An Optimized Race Engine

Demo Study: Results

All engine relevant postprocessing through HEEDS UI

Demo Study: Sample Results

BaselineBest Design

Demo Study: Performance

Model size: ~ 1 mio cells @ BDC (1 mm base size), time span 380 degrees crank angle (intake and compression stroke)

Total turnaround time per design: ~ 3 hours– Preprocessing, meshing, and postprocessing on 1 CPU: ~ 25

min

– Run on 48 CPUs: ~2.5 h

Parallel design assessment through HEEDS– Here 4 designs in parallel

~ 45 min per design occupying 192 CPUs

– 100 designs evaluated in 83 hrs

License requirements:– 2 es-ice pre/post

– 4 es-ice run

– 164 HPC STAR-CD

– 4 enablestar

– 5 STAR-CCM+

– 1 HEEDS

Transient port flow optimization (Pre-Sales demo–confidential)– Maximize tumble and trapped mass through port design optimization– Fully transient: 300 designs in 2 days on 64 cores

Diesel piston bowl shape optimization (JLR – customer presentation)– Presented at last year‘s European ICE Workshop in Maranello

Prechamber gas engine workflow (Support demo for Caterpillar)Gasoline spray calibration in a bomb experiment (Internal training) – Calibrate spray break-up model to match experimental properties

Automatic testing of es-ice automatic meshing performance (Internal)– Extraction of best practices and sensitivity study on meshing parameters

for optimum mesh quality

Evaluation of DARS combustion libraries in STAR-CD box model (Internal)– Tool to explore combustion libraries for auto-ignition and laminar flame

speed in CFD operating mode, valuable for library validation

Turbulent Jet Ignition (TJI) combustion model validation and best practice study (Internal)– Combustion model assessment and calibration

Examples of Successful In-Cylinder and Related Studies Using HEEDS/es-ice/STAR-CD

The Application of HEEDS MDO to the Optimization of Diesel Piston Bowl Design,

Paul Dunkley, Jaguar Land Rover

(Presented in Maranello at the European ICE Workshop 2015)

Paul D. of JLR stated that he can justify the investment in HEEDS purely because of cost savings due to process automation, even before running one single MDX study. Due to the advancements in es-ice automation transient full cycle es-ice/STAR-CD in-cylinder MDX is now possible!

Piston Bowl Optimization Demo (Internal)

SOOT NO

Prechamber gas engine workflow

(Support demo for Caterpillar)

• Challenge • Calibrate fuel spray of gasoline multi-hole injector

for a STAR-CD in-cylinder analysis by using a static spray chamber

• 4 Calibration parameters as design variables• Initial droplet PDF “Rosin-Rammler” X & Q

• Spray cone angle and nozzle diameter

• 2 Calibration objectives • Spray penetration length as function of time

• Droplet size distribution 60mm downstream

• Automated calibration process

• 15 min per case 8-10 hours total

• Impact by HEEDS• Curve fitting of two calibration objectives

• Manpower time savings automatic process does not require manual interaction

STAR-CD Spray Model Parameters

Curve Fitting by HEEDS

Final Spray Calibration

Gasoline spray calibration in a bomb experiment

(Internal training)

Automatic testing of es-ice automatic meshing performance

(Internal)– Test of meshing technology, extraction of meshing best practices, and

sensitivity study on meshing parameters for optimum mesh quality

Evaluation of DARS combustion libraries in STAR-CD box model (Internal)

– Tool to explore combustion libraries for Auto-Ignition and Laminar Flame Speed in CFD operating mode, valuable internal validation tool

Turbulent Jet Ignition (TJI) Combustion model validation and best practice study (Internal, ongoing)

Generic scripts for standard engine studies (meshing,

combustion, mixture preparation, etc.) will be delivered in a

consistent and version numbered manner together with STAR-

CD/es-ice installation

Maintenance, bug fixing, and enhancement of these scripts will

be managed (e.g. through GIT)

What Might Be Next?

HEEDS Portals have been delivered for es-ice/pro-STAR/STAR-

CD in the latest HEEDS release

The new portals enable automated workflows and design

exploration to be performed for in-cylinder transient

simulations in a convenient, easy, and consistent manner

The provided scripts allow for easy start up for new users

leaving full flexibility to advanced users and custom studies

Users touch neither the es-ice nor the pro-STAR GUI, leaving

required expertise to a minimum

Summary

Thank you for your attention