EGEE 520

A 2-D Diesel Particulate Filter Regeneration Model

Yu Zhang

EGEE 520

Introduction

Diesel particulate filter (DPF) collects diesel particulate (mainly soot) emissions.

A soot layer is formed over a porous wall and removed by combustion

(This soot layer removing process is referred as regeneration)

A 2-D time-dependent model for the cross-section of a filter channel is formed to get a better understanding of the DPF regeneration process

symmetry

symmetry

Soot layer

Porous wall

Inlet channel

outlet channel

EGEE 520

Governing Equations

Momentum Balances Navier-Stokes equation:

( in open channel)

Brinkman equation:

(soot layer and porous wall)

Mass Balance Maxwell-Stefan diffusion and convection

Energy Balance

uuuu 2)(

pt

0)(

ut

11121 p

kt

uuu

0)( 1

ut

iiii Rt

)( uj

n

kkikii D

1

~dj

QTCTkt

TC pp

) ( u

EGEE 520

Governing Equations

Chemical reactions

Reaction rate

Heat source

(R5) OC2O5.0OC

(R4) COOCOC2C (R3) COOC24CC

(R2) COO5.0C (R1) COO C

2e23e2

3e22e23e2e

222

'

1fii Kr ji

j

N

jC

iii

HrQ 1

RT

En

a

eATK

EGEE 520

Model Formulation

Plug

Plug

EGEE 520

Solution

T distribution at 200s and 500s P distribution at 0s and 500s

EGEE 520

Solution

Soot layer thickness distribution

EGEE 520

Validation

Exhaust back pressure comparison Soot layer thickness distribution without considering chemical reactions

Calculated

Literature

EGEE 520

Parametric Study

3.00E-05

3.50E-05

4.00E-05

4.50E-05

5.00E-05

5.50E-05

0.01 0.03 0.05 0.07 0.09 0.11 0.13

Filter length(m)

Soot

layer

thick

ness

(m)

t=20s T=350K

T=400K

T=420K

EGEE 520

Conclusion

Soot layer thickness distribution is non-uniform due to the non-uniform temperature distribution along the filter channel

Soot layer thickness is sensitive to the exhaust temperature. As exhaust temperature increases, the soot layer thickness decreases significantly