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Validation and Verification of ANSYS Internal Combustion Engine Software Martin Kuntz, ANSYS, Inc.

Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

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Page 1: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation and Verification of ANSYS Internal Combustion Engine Software

Martin Kuntz, ANSYS, Inc.

Page 2: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Contents

• Definitions

• Internal Combustion Engines

• Demonstration example

• Validation & verification

– Spray box

– Combustion

– Port flow applications

– IC engine applications

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 2

Page 3: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Contents

• Definitions

• Internal Combustion Engines

• Demonstration example

• Validation & verification

– Spray box

– Combustion

– Port flow applications

– IC engine applications

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 3

Page 4: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Definitions • Verification – Verify, that model is implemented correctly – Characteristics

• Simplified geometry • Focused on single physical model • Compare to analytical or other CFD

2012 Automotive Simulation World Congress 4 Wednesday, October 10, 2012

• Validation – Demonstrate simulation accuracy – Characteristics

• Realistic geometry • A combination of physical models • Compare to experimental data

• Demonstration – Illustrate application of software to generic case – Characteristics

• Realistic geometry • A combination of physical models • No comparison to data

Page 5: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Contents

• Definitions

• Internal Combustion Engines

• Demonstration example

• Validation & verification

– Spray box

– Combustion

– Port flow applications

– IC engine applications

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 5

Page 6: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

IC Engine Simulations Types

• Component simulations

– Intake port, intake manifold, water jackets, fuel injectors

– Spray bomb

• IC engine simulations

– Cold flow • Charge motion

– Combustion • Thermal management

• Emissions

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 6

Page 7: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

ICE Simulation Workflow

• Internal combustion engine simulation components – Preprocessing

• Geometry decomposition • Initial meshing • Simulation parameter definition

– Moving deforming meshes • Smoothing, remeshing, layering

– Particle tracking • Injection, tracking, evaporation, wall-interaction

– Combustion • Ignition, flame front propagation

– Post-processing • Automatic processing of monitor and solution data

2012 Automotive Simulation World Congress 7 Wednesday, October 10, 2012

Page 8: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Contents

• Definitions

• Internal Combustion Engines

• Demonstration example

• Validation & verification

– Spray box

– Combustion

– Port flow applications

– IC engine applications

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 8

Page 9: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Complete cycle setup – Initial conditions and boundary

conditions provided by 1D simulation

– Material Iso-octane

– Spray injection • 6-hole injector

• Double injection

• Transient mass flow

• Prescribed diameter distribution

– Liquid evaporation model

– Spark ignition

– G equation combustion

• Testcase provided by BMW

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 9

Courtesy: BMW

Page 10: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Initialization

– Burned conditions at EVO

• Boundary condition

– Specified temperature

• Mesh size: cell count

– 800.000 (TDC) to 1.600.000 (BDC)

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 10

Page 11: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Simulations

– Cold flow run

– Charge motion

• Plus spray injection

• Plus particle tracking

– Combustion • Plus ignition

• Plus flame front propagation

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 11

Page 12: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Cold flow simulation – Results for CFX and Fluent – Cylinder averaged values of pressure and temperature

Wednesday, October 10, 2012 12

Page 13: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Cold flow simulation – Results for CFX and Fluent – Swirl ratio, tumble ratio

Wednesday, October 10, 2012 13

Page 14: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Velocity vector plots

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 14

CA 330

CA 715 CA 555

CA 440

Page 15: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• First injection

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 15

Page 16: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Evaporation

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 16

Page 17: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Second injection

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 17

Page 18: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Total particle mass

• Influence of wall film model

Page 19: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Combustion simulation

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 19

Page 20: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Demonstration : Direct Injection Gasoline Engine

• Burned flow simulation – Cylinder averaged values

• Pressure • Temperature • Mixture fraction

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress

20

Page 21: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Contents

• Definitions

• Internal Combustion Engines

• Demonstration example

• Validation & verification

– Spray box

– Combustion

– Port flow applications

– IC engine applications

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 21

Page 22: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Particle Tracking

• Particle injection – Primary / secondary breakup – Injection type: cone / hollow

cone

• Tracking – Particle-wall interaction – Wall film modeling

• Evaporation

• Testcases – Bosch spray box (cold spray) – Hiroyasu spray box (cold spray) – Koss spray (hot spray)

Page 23: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

• Two cases based on experimental data from ROBERT BOSCH GmbH

• Details of experimental setup

Setup # 1 Setup # 2

Gas parameters

Gas type N2

Temperature [K] 300

Pressure [MPa] 0.11 0.56 Fuel Properties

Fuel type Heptane

Density [kg/m3] 614.2

Surface tension [kg/s2] 0.0201

Spray parameters

Initial temperature [K] 300

Nozzle diameter [mm] 0.151

Injection pressure [MPa] 10

Injection velocity [m/s] 138

Particle mass flow rate [g/s] 1.5

Injection rate, single pulse [ms] 1.5

Estimated initial spray angle [deg] 5.2 12

Injection Weber number 85 450

sampling point (0, 0.00275, 0.03) 0.03 m

0.00275 m

Available data

• Spray penetration over time

• Sampling point (0, 0.00275, 0.03)

- Droplet diameter distribution

- Droplet velocity distribution

Kumzerova, E. and Esch, T., “Extension and Validation of the CAB Droplet Breakup Model to a Wide Weber Number Range”, Proc. of the 22nd Europ. Conf. on Liquid Atomization and Spray Systems, Paper ILASS08-A132, Como Lake, 2008.

Validation: Bosch Spray Box

Page 24: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Bosch Spray Box

• Mesh dependence study

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 24

Grid Number of

cells

Size of the cell near the

nozzle [m2]

(radial x axial length)

Coarsest 364 12.8e-4 x 12.8e-4

Coarse 735 6.4e-4 x 6.4e-4

Medium 1450 3.2e-4 x 3.2e-4

Fine 2880 1.6e-4 x 1.6e-4

Finest 5824 8e-5 x 8e-5

Fine Finest

Medium Coarse Coarsest

Page 25: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Bosch Spray Box

• Mass penetration

• Mesh dependence study

• Fluent simulation

• Setup #2

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 25

Page 26: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Bosch Spray Box

• Local spray results at sampling point

– Droplet diameter distribution

– Local velocity distributions

– KH-RT breakup model

– Setup #1

Page 27: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Bosch Spray Box

• Local spray results at sampling point

– Droplet diameter distribution

– Local velocity distributions

– KH-RT breakup model

– Setup #2

Page 28: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Bosch Spray Box

• Mass penetration

• Comparison KH-RT and SSD break-up model

• Fluent simulation

• Setup #2

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 28

Page 29: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Bosch Spray Box

• Mass penetration

• Comparison of break-up models

• CFX simulation

• Setup # 2

T i m e [ s ]

P e n

e t r a

t i o n D

e p t h

[ m ]

0 0 . 0 0 0 5 0 . 0 0 1 0 . 0 0 1 5 0 . 0 0 2 0

0 . 0 2

0 . 0 4

0 . 0 6

0 . 0 8

0 . 1 E x p e r i m e n t N o b r e a k u p R e i t z & D i w a k a r S c h m e h l T A B E T A B C A B

M e d i u m g r i d ( 4 0 0 0 n o d e s ) d t = 2 e - 6 s

Page 30: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Hiroyasu Spray Box

Case 1 Case 2 Case 3

Gas parameters

Gas type N2

Temperature [K] 300 300 300

Pressure [MPa] 1.1 3.0 5.0

Fuel Properties

Fuel type C12H26

Density [kg/m3] 840

Surface tension [kg/s2] 0.0205

Spray parameters

Initial Temperature [K] 300 300 300

Injection Velocity [m/s] 102 90 86

Particle Mass Flow

Rate [g/s] 6.05 5.36 5.13

Nozzle diameter [mm] 0.3 0.3 0.3

Injection rate, single

pulse, ms 2.5 4 4

Page 31: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Hiroyasu Spray Box

• Mass penetration

• Case 1, 2 and 3

• Fluent simulation

Page 32: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Koss Spray Box

Gas Temperature [K] 800

Gas Pressure [MPa] 5

Gas Type N2

Particle Mass Flow Rate [g/s] 4.62

Droplets type nHeptane (C7H16)

Density [kg/m3] 684

Surface tenstion [N/m2] 0.02

Nozzle diameter [mm] 0.2

Injection rate [ms] 1.3

Droplet diameter [mm] 0.2

Injection Velocity [m/s] 215

Initial spray angle [deg] 10.1

Measurements: H. Koss, D. Bruuggemann, A. Wiartalla, H. Backer, and A. Breuer, Results from Fuel/Air Ratio Measurements in an N-Heptane Injection Spray, IDEA periodic report, RWTH Aachen, 1992.

• Evaporating spray

– Liquid penetration at 90% spray mass fraction

Liquid penetration Length

Page 33: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Koss Spray Box

• Breakup model comparison

– TAB

– ETAB

– CAB

– Reitz

• CFX run

Wednesday, October 10, 2012

Page 34: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Koss Spray Box

• Comparison

– Fluent KH-RT model

– CFX TAB model

Wednesday, October 10, 2012

Page 35: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Contents

• Definitions

• Internal Combustion Engines

• Demonstration example

• Validation & verification

– Spray box

– Combustion

– Port flow applications

– IC engine applications

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 35

Page 36: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Hamamoto Testcase

• Premixed combustion in a closed vessel with fixed wall

• Propane/air mixture:

– Equivalence ratio =1.0

• Measured data

– Optical access

– Pressure transducer

– Described in • Hamamoto et al. (1988)

• Ewald (2005) Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 36

Page 37: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Hamamoto Testcase

• Average cylinder pressure

– Mesh sensitivity study Fluent, 2d quad meshes

– Comparison CFX vs. Fluent

Page 38: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Hamamoto Testcase

• Average cylinder pressure

– Comparison of mesh size and types

– 3D hexahedral and tetrahedral meshes

Page 39: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

• Premixed combustion • Flat head, flat piston, SI ICE • Fuel: C3H8

• References: – Alkidas (1980) – Han and Reitz (1997)

• Simulated interval [-30;30 CA] ATDC • Piston motion

Displacement [m3] 0.82 x 10-3

Bore x Stroke [mm] 105.0 x 95.25

Compression ratio 8.56

Connecting rod length [mm] 158

TDC clearance [mm] 12.6

Equivalence ratio 0.87

Engine speed [rpm] 1500

Spark timing [deg. ATDC] -27

Volumetric efficiency 40

Combustion Validation: Pancake Engine

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 39

Page 40: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Combustion Validation: Pancake Engine

• Average cylinder pressure

• G equation combustion

• Comparison

– CFX

– Fluent

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 40

Page 41: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Contents

• Definitions

• Internal Combustion Engines

• Demonstration example

• Validation & verification

– Spray box

– Combustion

– Port flow applications

– IC engine applications

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 41

Page 42: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

ICE Validation

• IC engine applications

– Public engine cases

– Collaborations with customers

– Benchmark for customers

– Of interest

• Valuable experimental data

• No confidentiality

• No restrictions for publication

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 42

Page 43: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

ICE Validation: Engine Applications

• Port flow simulation

– Thobois generic engine

• Cold flow simulation

– Bosch: direction injection diesel engine with PIV data

• Partially premixed combustion

– Wisconsin: direct-injection spark-ignition engine

• Premixed combustion

– Ducati: premixed engine setup

• Diesel combustion

– Engine cooling simulation

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 43

Page 44: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

ICE Validation: Port Flow

• Steady intake flow conditions • Testcase defined in – Large Eddy Simulations in IC Engine Geometries

• Thobois, Rymer, Souleres, Poinsot • SAE Paper, 2004-01-1854

Port length 132 mm Inner port diameter 16 mm Outer port diameter 34 mm Valve opening 10 mm Cylinder length 300 mm Cylinder diameter 120 mm

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 44

Page 45: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

ICE Validation: Port Flow

• Comparison

– RANS SST model

– LES SAS model

• CFX results

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 45

Isosurface

Color – eddy viscosity

622 10S

Page 46: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

ICE Validation: Port Flow

• Plane @ 20 mm

• Mean Axial Velocity • Axial Velocity Fluctuation

Page 47: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

ICE Validation: Port Flow

• Plane @ 70 mm

• Mean Axial Velocity • Axial Velocity Fluctuation

Page 48: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Bosch Engine

• Experiment – Investigation of Diesel engine in-cylinder flow with Particle Image

Velocimetry (PIV) and High-Speed PIV – Generation of a comprehensive and high-quality database for Large

Eddy Simulation • Simulation – RANS & Scale resolving turbulence models, e.g. LES, DES – CFX simulation

• Publications – “A Strategy for Evaluation of LES Applied to Diesel Engine In-

Cylinder Flow – Joint Effort of Simulation and Experimental PIV Flow Analysis” – Les Rencontres Scientifiques de l'IFP – LES for Internal

Combustion Engine Flows - 18-19 November 2010 – Analysis of In-Cylinder Air Motion in a Fully Optically Accessible

2V-Diesel Engine by Means of Conventional and Time Resolved PIV – 9TH INTERNATIONAL SYMPOSIUM ON PARTICLE IMAGE

VELOCIMETRY – PIV’11, Kobe, Japan, July 21-23, 2011

Page 49: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

NR z

s

2

V

V

Vr

Vvr

d

d

2

-1

0

1

2

3

4

5

360 450 540 630 720

[cad]

Sw

irl R

ati

o [

-]

Simulation

Experiment

CFX ICE Swirl

Validation: Bosch Engine

• RANS simulation

– Flow characteristics swirl

Average swirl on planes

Experiment (plane data)

Swirl ration in cylinder

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 49

Page 50: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Bosch Engine

• Scale Resolving Models

– LES – Large Eddy Simulation

– DES – Detached Eddy Simulation

– SAS – Scale Adaptive Simulation

• Grid size:

– 1.2 – 6.8 · 106 nodes

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 50

Page 51: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Bosch Engine

• Comparison of velocity profiles – Sample line: -10mm below

dome – Exp: 2D-2C absolute velocity

Sim: 3D-2C absolute velocity

Sample Line

Page 52: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Wisconsin Engine

• Research project conducted at University of Wisconsin sponsored by ANSYS Inc. – “Characterization of Direct-Injection

Spark-Ignition Operation and Investigation of Particulate Matter Formation"

– Research work of single-cylinder direct-injection spark-ignition engine

– November 2011 – November 2013

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 52

Page 53: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

• Riccardo Hydra Base

• Modern DISI engine architecture

Engine Specifications

Engine Type 4-Stroke, 4-Valve, SI

Chamber Geometry Pentroof

Fueling type Spray-guided direct-

injection

Displacement 692.9 cm3

Compression Ratio 12:1

Injection Pressure 11 MPa

Single-cylinder direction-injection spark-ignition engine used for

measurements

Validation: Wisconsin Engine

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 53

Page 54: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Wisconsin Engine

• Phase 1 single cylinder metal engine – Motored operation – Fired homogeneous (fully vaporized) spark-ignition

operation with premixed air/fuel mixtures – Direct-injection spark-ignition operation

• Phase 2 detailed investigations – Detailed spray characterization measurements in a

spray vessel – Laser-based in-cylinder measurements to characterize

the velocity field or fuel distribution – Detailed measurements of particulate matter number

count

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 54

Page 55: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Wisconsin Engine

• Motored Engine Measurements

• Repeatability • Influence of coolant temperature

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 55

In-cylinder pressure for 2000 rpm 80 kpa, 80 oC intake, 80 oC coolant

4

6

81

2

4

6

810

2

Cyl

ind

er

Pre

ssu

re [

ba

r]

5 6 7 8 9

0.12 3 4 5 6 7 8 9

1

Volume [L]

Page 56: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Ducati Engine

• 4-stroke S.I. P.F.I. race engine

• Premixed combustion

• Validation / verification

– Pressure trace

• Collaboration

– University of Bologna, Ducati Motor Holding & ANSYS

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 56

• Publication – ”Flexible Meshing Process and Multi-cycle Methodology for

Simulating Reacting Flows in High Performance SI Engines with ANSYS CFX” • International Multidimensional Engine Modeling User’s Group Meeting

2010 (IMEM 2010), Detroit, April 12th, 2010

Page 57: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Ducati Engine

• Simulation with CFX

– Efficient multi-cycle methodology

• Single-cycle initialization / multi-cycle initialization

– Influence of mesh resolution & types

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 57

Page 58: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Ducati Engine

• Simulation with Fluent

– Variation of combustion models / turbulent flame speed models and settings

-20

0

20

40

60

80

100

120

140

-360 -270 -180 -90 0 90 180 270 360

EX

P.

MEA

N I

N-C

YLIN

DER

PR

ES

SU

RE

[bar]

CRANK ANGLE [deg. ATDC]

10000 rpm -Cyl_Horiz10000 rpm -Cyl_VertECFM - cycle 1

C-eqn - cycle 1

G-eqn - cycle 1

G-eqn zcd - cycle 1

G-eqn p - cycle 1

G-eqn pc - cycle 1

Ave

rage

cyl

ind

er p

ress

ure

[b

ar]

Crank Angle [deg] 2012 Automotive Simulation World Congress 58 Wednesday, October 10, 2012

Page 59: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Engine Cooling Simulation

• Perform Engine Cooling Simulation

– Requires simultaneous simulation • IC engine simulation

• Cylinder head coolant channel simulation

– Thermal inertia of two models is orders of magnitude different two separate simulations

2012 Automotive Simulation World Congress 59 Wednesday, October 10, 2012

Page 60: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Engine Cooling Simulation

Temperature profile on the firedeck

Time-averaged Heat Flux profile on cylinder

head

Steady state conjugate heat

transfer of cylinder head

Transient combustion

simulation in diesel engine

in-cylinder

Iterative Process

Page 61: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Engine Cooling Simulation

Import: temperature data

Export: time-averaged heat flux from IVC to EVO

Iteration process

Page 62: Validation and Verification of ANSYS Internal Combustion ... · PDF fileValidation and Verification of ANSYS Internal Combustion Engine Software ... •Internal Combustion Engines

Validation: Engine Cooling Simulation

y+~ 200 y+~ 30

y+~ 20 y+~ 1

• Heat Flux

• n-heptane 1 step mechanism

• Effect of mesh resolution

2012 Automotive Simulation World Congress 62 Wednesday, October 10, 2012

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Validation: Engine Cooling Simulation

• Heat Flux

• n-heptane 1 step mechanism

• Effect of combustion and turbulence model

Laminar Finite Rate

K-epsilon

Finite Rate - Eddy

SST K-w SST K-w

Laminar Finite Rate

2012 Automotive Simulation World Congress 63 Wednesday, October 10, 2012

Finite Rate - Eddy

K-epsilon

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Validation: Engine Cooling Simulation

• Temperature data at locations of thermocouples

– Heat Flux n-heptane 1 step mechanism + SST k model (Laminar Finite Rate)

Wednesday, October 10, 2012 2012 Automotive Simulation World Congress 64

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Summary

• Validation and verification examples related to internal combustion engines – Basic spray and combustion cases – Port flow applications – Cold flow IC engine applications – Combustion IC engine applications

• Good agreement of results for most cases in different application areas

• Ongoing work in the ICE validation project at ANSYS – Continuation of work with existing engines – Collection of new validation cases – Reference cases for current ICE software and future

software developments

2012 Automotive Simulation World Congress 65 Wednesday, October 10, 2012

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Any Questions ?

2012 Automotive Simulation World Congress 66 Wednesday, October 10, 2012