egee 520 a 2-d diesel particulate filter regeneration model yu zhang
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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