TRANSIENT FLUID FLOW ANALYSIS INSIDE

AN INTAKE MANIFOLD APPLIED TO DIESEL

ENGINE

Fabio Yukio Kurokawa, Celso Argachoy

MWM International Motores

Rodrigo Peralta, Marcelo Kruger, Martin Kessler,

Geraldo Severi

ESSS

PRESENTATION TOPICS

• Company Overview;

• Problem Description / Goals;

• Methodology;

– Stages;

– Computational Model;

– Results;

• Remarks and next steps.

Established in 1902

World Headquarters in Warrenville, IL

Total Worldwide Employees: 17,800

More than 1,000 Truck dealer locations

across North America

Distributors in more than 70 countries

Operations in USA, Brazil, Canada, India,

Mexico and Argentina

NAFTA

Global

Business Unit

North America

Business Unit

Mercosur

Business Unit

Worldwide Leader

3 to 15L Diesel Engines

270,000 Units (2009)

NAVISTAR ENGINE BUSINESS

• 100% Navistar subsidiary

• 57 years diesel engines manufacturer leader

in South America

• More than 3,6 millions engines produced for

several applications

– Vehicular

– Agricultural

– Industrial and

– Marine

Mercosul

Sprint / 10 series

Acteon / 229 series

Big Bore Blocks

NGD 3.0 /

NGD 9.3 / MS series

Systems and parts

machining for

diesel engines

MWM INTERNATIONAL MOTORES

São Paulo - Brazil Canoas - Brazil J M - Argentina

Diesel Engines production

301;214 units (Aug’ YTD 2010)

MWM32%

A16%B

19%

C13%

D5%

E1%

F3%

G3%

H5%

I0%

J3%

Mercosul Diesel Production

Problem description - Goals

• To evaluate transient fluid flow regime inside

an intake manifold.

• Challenge:

Develop a numerical model without

considering the valves displacement, but

that is able to represent the transient flow

behavior;

Goals: Develop a computational model that represents the fluid flow

inside an Intake Manifold;

Methodology

Develop a computational model on ANSYS CFD that represents the fluid

flow inside an Intake Manifold;

Validate the ANSYS CFD results with GT-Power results.

Evaluate the influence of replacing the discharge coefficient by porous

zone;

Stages

1st Stage > Developed a model using the ANSYS Fluent

• transient, turbulent, compressible and single phase flow;

• replace the discharge coefficient by a porous zone;

• Journal File to control the transient cycles;

2nd Stage > Developed a model using the ANSYS CFX

• transient, turbulent, incompressible and single phase flow;

• replace the discharge coefficient by a porous zone;

• Multi-Configuration Simulations control the transient cycles;

Initial & Boundary Conditions

Time dependencies

(per cycle):

Detail of replacing the discharge

coefficient by a porous zone;

1st Stage – ANSYS Fluent

Porous domain

Fluid domain

Inlet:

Mass Flow

Outlets: Pressure

1st Stage – ANSYS Fluent

-2,00

-1,50

-1,00

-0,50

0,00

0,50

1,00

1,50

2,00

2,50

3,00

0 100 200 300 400 500 600 700

Dim

en

sio

nle

ss F

low

Crank Angle [deg]

Valv1

Valv2

Valv3

Valv4

Valv5

Valv6

Intern Outlet

• Presence of backflow can be noted on the

plot

1st Stage – ANSYS Fluent

There is a great quantity of backflow;

The imposed boundary condition at the outlets (transient pressure), was

not able to reproduce the effects generated by the opening valve.

REMARKS

The porous zone at ANSYS FLUENT works only for the thermal energy

equation (when imposing porosity);

Detail of replacing the

discharge coefficient

by a porous zone;

– Included another fluid

domain to improve the

boundary condition.

2nd Stage – ANSYS CFX

Porous domain

Fluid domain

2nd Stage – ANSYS CFX

13 Simulations per cycle: Flow analysis +

Configuration

Each simulation with different boundary conditions

set in Flow Analysis;

Simulations controlled by activation control on

respectively configuration:

Ex: Begin new simulation when last simulation is over

using this results as initial condition;

Multi-Configuration Simulations

2nd Stage – ANSYS CFX

Initial conditions:

• 1st simulation: Air stagnant

• Others simulations: Result from

previous simulation

Boundary conditions:

• Walls

– No slip

• Inlet

– Prescribed mass flow (time-

dependent)*

• Outlets: Opening

– Opened cylinder: Prescribed relative

pressure (time-dependent)*

– Closed cylinder: Prescribed relative

pressure: 0 Pa

• Porous zone

– Opened cylinder: Permeability

calculated by discharge coefficient

(time-dependent)*

– Closed cylinder: Infinite resistance

2nd Stage – ANSYS CFX

Similar behavior between

ANSYS CFX and GT-Power

results.

Backflow

Remarks

The Multi-Configuration method showed a good alternative to model the

flow inside the intake manifold without considering the valves

displacement;

The reliability of the results increases the confidence in the computational

model for implementing new configurations;

Next steps

Compressible flow simulation using ANSYS CFX;

Coupling ANSYS CFD with GT-Power;

Thank you for your attention.