Induced Particle Grouping Induced Particle Grouping and Coagulation in Diesel and Coagulation in Diesel

ExhaustExhaust

ItamarItamar Hite, Michal Hite, Michal RuzalRuzal MendelevichMendelevich, Tal , Tal ShakkedShakked, , Prof. Prof. EranEran SherSher and Prof. David and Prof. David KatoshevskiKatoshevski

BenBen--Gurion University of the NegevGurion University of the NegevBeerBeer--ShevaSheva, Israel, Israel

IAAR 23IAAR 23rdrd Annual Meeting Annual Meeting February 10, 2010February 10, 2010

Reduce Air PollutionReduce Air Pollution

Small particles have two main Small particles have two main aspects:aspects:

Penetrate into the respiratory Penetrate into the respiratory systemsystemResidence time in the airResidence time in the air

2pt DU ∝

11 micron particle will stay micron particle will stay 100 100 times times longer that longer that 1010 micronmicron

Decreasing the subDecreasing the sub--micron and microns particles (PM)micron and microns particles (PM)

Reduce Air PollutionReduce Air PollutionLarger particles are:Larger particles are:

Able to filtrateAble to filtrateStay shorter time in the airStay shorter time in the airHave a lower penetration potential into the Have a lower penetration potential into the respiratory system respiratory system

What is Grouping?What is Grouping?

The grouping phenomena was examined and proven itself in systems like:

-Suspended sediment in tidal channels.

-Fuel spray in flame.

1D Model for a Standing Wave 1D Model for a Standing Wave Velocity FieldVelocity Field

Particle positionStokes numberFlow velocity−

−−

*

*

UStx

−>−

−

)1(

*

*

CUU

b

a Average velocityAmplitude velocityConstant

( )*** 1 xUSt

x −=

( )CtxUUU ba +−= )sin()cos( *****

*asterisks denote dimensionless parameters

1D Model for a Standing Wave 1D Model for a Standing Wave Velocity FieldVelocity Field

( )StU

CtxStU

xSt

x ab

***

*** )sin()cos(1

=+++

( )*

* 1

b

a

UU −

=βThe creation of grouping is depands on

Stable Grouping β<1

Non-grouping β>1

bStU2

=αGrouping also require α>>β when

Stable grouping & NonStable grouping & Non--groupinggrouping

*

1*

bU

aU ⎟⎠⎞⎜

⎝⎛ −

=β

Stable Grouping β<1 Non-grouping β>1

Building The ExhaustBuilding The Exhaust

The exhaust shape induce standing wave flow fieldFor stable grouping the exhaust dimensions were planned to create β<1Every engine needs a different modified exhaust because the particles are emitted in a different velocity.

( )CtxUUU ba +−= )sin()cos( *****

The Standing Wave velocityThe Standing Wave velocity field:field:

The ExperimentsThe Experiments

Mitsubishi S3L engineMitsubishi S3L engine

ThreeThree--cylinder, 4cylinder, 4--strokestroke

Displacement volume: 1,125 cm3 Displacement volume: 1,125 cm3

11.8kW at 1,500 rev/min 11.8kW at 1,500 rev/min

We control engine speed and engine

load

Size analyzer: SEMTECH PM-300. laser light scattering

300nm-2μm

ResultsResults

regified MMfractionmass −=Δ mod_

Changes in the mass fraction as a function of the particle's diameter

RPM=1500load=6V

-0.3-0.2-0.10.00.10.20.3

0.35 0.45 0.57 0.72 0.90 1.30 1.80 2.00

Dp[µm]

∆mass fraction

ResultsResults

Characterization For Grouping as a Function of the Angle

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

1 2 3 4 5 6 7 8 9 10 11 12

Voltage [v]

Ang

le [r

ad]

1500rpm1700rpm1900rpm

Comparing Operation Conditions

Influences of the Modified Influences of the Modified Exhaust on the EngineExhaust on the Engine

No significant change in fuel consumptionPressure loss negligibleNo significant decreasing in the engine power

SummerySummerySystem Schematics – Enhancing Grouping

Main ConclusionsMain Conclusions

Grouping phenomena was observed in Grouping phenomena was observed in modified pipe.modified pipe.A new approach for reducing PM from A new approach for reducing PM from exhaust systems.exhaust systems.Grouping is more significant in the low Grouping is more significant in the low values of speed engine.values of speed engine.

Future StepsFuture Steps

Improve the grouping Creation of grouping with combination of other wave fields (like acoustic waves)Using this concept of modified pipe to reduce pollution from other devices (forklift)

ReferencesReferencesKatoshevski D., Shakked T., Sazhin S., Crua C., Heikal M.R. (2008), Grouping and trapping of evaporating droplets in an oscillating gas flow, International Journal of Heat and Fluid Flow Vol 29, pp. 415–426

Sergei Sazhin, Tal Shakked, Vladimir Sobolev, David Katoshevski (2008), Particle grouping in oscillating flows, European Journal of Mechanics B/FluidsVol 27, pp. 131–149

Winter C., Katoshevski D., Bartholomä A., Flemming B.W. (2007), Grouping dynamics of suspended matter in tidal channels, J. of Geophysical Research, Vol 112, C08010, doi:10.1029/2005JC003423

Katoshevski D., Dolin Z., Ziskind G. (2005), Aerosol clustering in oscillating flows: mathematical analysis, Atomization and sprays, Vol 15, pp. 401-412

Questions?Questions?