Mechanical webinar 2011

Modeling Mechanical System Interactions in Flowmaster Automotive Fuel Injection and Aircraft Hydraulics

Actuation System Examples

Shayne ZieglerFlowmaster USA

USA Call-in Number: 1-631-267-4890Click “Global Call-in numbers for other regions

Access Code: 958 533 404

Arlie NuetzelFlowmaster USA

Sudhi UppuluriComputational Sciences

Expert Group

© Flowmaster Group © Flowmaster Group © Flowmaster Group 2011© Flowmaster Group

Agenda

• Overview of Flowmaster

• Introduction to Electro-Mechanical Components

• Case Study: Aircraft Hydraulic Actuation System

• Case Study: Gasoline Fuel Injection System

• Question & Answer Session


Flowmaster Overview - Analysis Capabilities

• Incompressible and compressible analysis• Water, Oil, Fuel, compressible air, natural gas, etc…• Mach Number / choking considerations for compressible

• Steady state scenarios• Snapshot results for given system conditions

• Transient scenarios• Time changing results in response to varying conditions.• Examples:

• Aircraft flight profile (long transient)• Valve/ pump shutdown - Fluid Inertia Considerations (fast transient)• Bleed air pneumatics and boundary condition varying transients.• Thermal Transient



• Heat transfer• Pipe Heat Transfer• Heat Exchanger• Solids Components: Complex or Conjugate Heat Transfer (Convection,

radiation, conduction)• Thermal analysis throughout the system.

• Design Options

• Sizing \ Flow Balancing

• Parametric Analysis• Built – in Features• COM Automation with Excel



• Aerospace• Gas / Liquid Interface Tanks for Propulsion• Body Forces Analysis for Fuel Systems• ECS Pack Components and Humidity

• Automotive• Under hood Airflows / Segmented Analysis• Lubrication Bearing Models• AC Systems / Cabin Comfort Model

• Gas Turbine• Secondary Flows: Swirl Solver, Cavity Analysis, Radial, Axial, and Tangential

flow vectors• Combustion: Conjugate Heat Transfer and Equilibrium Heat Release (custom)

• Oil and Gas• GIS Data Import• Pipeline Profile (Excel Data / Pods) Import.• Pipeline Results Analyzer• Buried and Partially Buried Pipe Heat Transfer Options


Flowmaster In Aerospace

Where Can Flowmaster Be Used In Aerospace?

• ECS Systems• Bleed Air Systems• Ice Protection Systems• Fuel Systems• Hydraulic Systems• Potable Water Systems


Aerospace Fuel System Example


Flowmaster In Automotive


Automotive Cooling Example

Cabin airside

Under hood Airflow

Drive Cycles

Cooling System

Lubrication System

Introduction to Electro-Mechanical Components


Damper Spring End Stop Port

Force Solenoid Mass Earth

Lever Lever Spacer Friction

Piston:Double Acting

Piston:Single Acting

CompressibleCylinder

Introduction to Electromechanical Components


DCV: 2 port

DCV: 3 Port

DCV:4 Port

DCV:4 Port

PD Pump Hydraulic Motor

Hybrid Pump

Elastic Pipe (MOC)

Cylinder:1R1A

Cylinder:1R2A

Cylinder:2R2A

Volume



Reference: virtual.cvut.cz/dynlab/courseModeling/node43.html

Mechanical - Fluid Interaction Modeling

• Spool Valve

• Fuel Injector Valve

Reference: www.answers.com/topic/fuel-injection



Introduction to Electromechanical Components: Fluid Transients


Pressure waves travel through the pipe at the speed of sound. The passage of these waves is calculated using the Method of Characteristics, assuming a constant wave speed. Pressure in the system is directly related to velocity (flow rate).

In transient events flow rate changes cause pressure fluctuations (and vice versa). For rapid transient events the pressure rise is:

∆P = a * ρ* ∆v

Where:

∆P = Pressure change in fluid

ρ = Liquid density

∆v = Velocity change

a = Wave speed

‘Fluid Transients in Systems', Wylie & Streeter, Published by Prentice Hall 1993, ISBN 0-13- 322173 -3.

Introduction to Electromechanical Components: Fluid Transients

tEd

k 1

1


Investigation: Pressure Surge Transient Analysis


Investigation: Pressure Surge Transient Analysis



Damper

Spring

End Stop

Force

Mass

EarthPort



Aerospace Applications of Mechanical Components

Arlie NuetzelApplications EngineerFlowmaster USA, Inc


Mechanical System Challenges

• System Sizing• Pump Capacity• Pressure Requirements• System Volume• Hydraulic Power vs. Speed• Packaging

• Survivability• Failure Modes• Redundancy

• System Interactions• Resonance• Cavitation• Controller Oscillation


Standard PD Pump Component

• Hydraulic PD pump• Pseudo-transient, time averaged output

Speed Controller

Pressure Gauge


PD Pump Output Results

Speed Controller

Pressure Gauge


Developing a Mechanical PD Pump Model

(S/2)

• Piston Based• Equation of Motion:

• Controller Script:

• Inlet/Outlet Valves• Simple Check Behavior


PD Pump Model Performance


Three Piston PD Pump


Transient Results

• fd


RPM sweep to find resonance



FFT


Hydraulic System Modeling

• Pump• Flap Actuator• Slats Actuator• Landing Gear

• Door Actuator• Gear Actuator


Flap/Slat Actuator

• Directional Control Valve• Flow Restrictor• Hydraulic Motor• Jack Screw (controller)


Landing Gear Actuator

• Directional Control Valve• Flow Restrictor• Hydraulic Piston• Mechanicals

• Mass• End Stop• Earth


Control Surface positions

• Master Controller



Custom Display


Fuel Injector Dynamics Modeling

Sudhi UppuluriPrincipal Investigator

Computational Sciences Experts Group(781) 640-2329

Fuel Injector Dynamics Modeling

Sudhi Uppuluri, Principal InvestigatorComputational Sciences Experts Group, LLC

(www.cseg.us)

WE ARE CSEG

We don’t sell software. We bring our modeling expertise and make your CAE software do

advanced stuff.

The stuff you bought the software to do to begin with.

Where CSEG fits in

CSEG

Your Design Team

Augment your team with expert simulation

capability

• Deep expertise on system modeling

• Brings best-in-class tools to the table

• Added resource to your design team

Don’t just buy software. Add simulation capability to your team.

A smart approach to simulation

Traditional approach• Evaluate which software to buy

with a trial license

• Purchase software tool

• Schedule and pay for training• Go through the learning curve of

the tool while building the model

• Spend ~2-3 yrs gaining competence and confidence on modeling with the new tool

CSEG approach• CSEG does the analysis and provides

you with a simulation answers quickly (CSEG bring the right tools and manpower to the table)

• Choose the right software once the analysis is done (CSEG provides the models)

Very cost-effective Have simulation answers quickly (with

confidence in them) Meet your analysis deadlines Significantly shorten the learning

curve Get calibrated model of your system

built by experts immediately.

Expensive approach Lost opportunity costs Simulation tool not effective during the

initial period Software training does not cover your

application.

Our Approach

• We focus on the problem, combining the right tools to provide accurate answers for your simulation challenge – not the tool any one company is selling. CSEG maintains licenses for best in class COTS tools providing instant technical capability expansion to your projects.

System Tools• Flowmaster*• Amesim• Gamma Technologies

Optimization Tools• iSight*• ModeFrontier

CFD Tools• Ansys Fluent• STAR-CD

Other• Matlab/Simulink• Can integrate your

in-house software with COTS

Gasoline Direct Injection

• Simplified Example of electronically controlled gasoline direct injection system

* Example layout from Wikipedia, retrieved Oct 2011

The system model

Engine Control Unit(Simulink)

Cylinder firing Timing, Voltages

Fuel consumption

Integrate with engine control to evaluate and optimize fuel consumption

Precise engine-management software to accurately tailor fuel-injection timing and duration

1D translation of the injector

* Reference from Advanced Engine Technology, Heinz Heisler

Modeling Considerations(Mechanical)

Coefficient of restitution to model needle bouncing

Modeling Considerations(Fluid)

Pressure waves inside the passages

CdDischarge Coefficient

Combustion chamber pressure

Injector Dynamics

12

3

Flow rate fluctuations from supply pressure variations

Needle bouncing

Pressure waves from needle closure

1

2

3

Overall Network

Which variables should I really spend a lot of time getting right ?

What about:supply pressure fluctuations?

Coefficient of Discharge?Needle mass?

Parameter study

• Sensitivity study of select input parameters performed using Isight by Simulia.

• Isight linked with Flowmaster through MS Excel

• Automated input generation, runs and results extraction

Parameter Study(an example)

* Analysis using Isight by Simulia

Shows effect of select variables on amount of fuel injected

Extremely Important that we get the needle port area, Cd and fluctuations in the supply pressure accurately characterized.

Variables such as Coefficient of Restitution, and fuel filter loss were not that important in this case.

Parameter Study(an example)

* Analysis using Isight by Simulia

Fluctuations in input parameters

Flu

ctu

ati

on

s in

mass o

f fu

el in

jecte

d

Calculating Cd

• Discharge coefficient directly affects the fuel flow rate through the injector.

• Cd is typically a function of injector port area.

• Few ways of determining Cd– Literature indicates Cd range from 0.690.73 (references avbl)

with some examples much higher.

– CFD is a good way to determine the Cd for your particular injector (at varying port openings) (predictive)

– Can back-calculate from available test data (non-predictive)

FURTHER DISCUSSION

Sudhi Uppuluri has over 14 years of experience in the simulation industry. He worked as a consulting engineer and sales manager at Flowmaster USA for 8 years .He has various technical publications on related subjects in SAE and AIAA journals. He holds a Masters in Aerospace Engineering from the University of Illinois at Urbana-Champaign and a Certificate in Strategy and Innovation from the MIT Sloan School of business.

Contact:Sudhi UppuluriPrincipal Investigator

[email protected](781) 640 2329www.cseg.us


Thank you for attending!Please use the “Raise hand” icon to ask technical questions...

For additional information, please contact…

Question & Answer Session

Flowmaster Sales inquires: [email protected]

847-901-4224

Flowmaster Support inquires: [email protected]

847-901-4242

Sudhi UppuluriPrincipal Investigator

Computational Sciences Experts Group(781) 640-2329

mailto:[email protected]

mailto:[email protected]