A One-Dimensional Model for Particulate Deposition and Hydrocarbon Condensation in Exhaust Gas Recirculation Coolers

Figures & data

FIG. 1 Computational domain of the model and a single computational cell.

FIG. 2 Particle distribution at pipe inlet. (a) Fractional distribution; (b) Cumulative distribution.

FIG. 3 Particle bin distribution at pipe inlet.

FIG. 4 Different forces acting on a particle resting on a flat surface and exposed to a shear flow. Point O is the fulcrum of rolling. (Abd-Elhady et al. 2010).

TABLE 1 HC species included in the model

Molecular formula	Name
C15H32	Pentacosane
C17H36	Heptacosane
C19H40	Nonadecane
C20H42	Eicosane
C22H46	Docosane
C24H50	Tetracosane

TABLE 2 Boundary conditions of test case for model evaluation

Parameter
Tube inner diameter	9.2 mm
Tube length	0.21 m
Soot mass concentration	Co: 10 mg/m^3
Soot number concentration	No: ∼10^12 #/m^3
Inlet gas temperature	673 K (400°C)
Coolant (wall) temperature	308 K (35°C)
Flow rate	5.2 kg/hr
Inlet gas velocity	20 m/s
Average pressure	150 kPa
Exposure time	6 h

TABLE 3 HC species concentrations

HC species	Concentration (ppm)
C15H32	10
C17H36	5
C19H40	5
C20H42	5
C22H46	5
C24H50	2

FIG. 5 Variation of deposit layer thickness along the tube length at different exposure times.

FIG. 6 Variation of the surface temperature of the deposit layer along the tube length at different exposure times.

FIG. 7 Condensed mass of different HC species in the tube as a function of time.

FIG. 8 Net soot mass and total HC condensed mass deposited in the tube as a function of time over 6 h.

FIG. 9 Effectiveness of the single tube heat exchanger as a function of time.

FIG. 10 Evolution of the particle bin distribution in the gas along the tube. (a) t = ½ h; (b) t = 6 h.

FIG. 11 Evolution of the deposit mass distribution as a function of time at (a) Tube Inlet; (b) Tube Outlet.

FIG. 12 Schematic flow diagram of the experimental setup (Abd-Elhady et al. 2010).

TABLE 4 Boundary conditions for experiments

Parameter
Tube inner diameter	9.2 mm
Tube length	0.21 m
Soot mass concentration	C o : 100 mg/m^3
Soot number concentration	N o : ∼10^13 #/m^3
Inlet gas temperature	673 K (400°C)
Coolant (wall) temperature	353 K (80°C)
Flow rate	4.94, 11.5 and 19.75 kg/h
Inlet gas velocity	30, 70, and 120 m/s
Average pressure	101 kPa
Exposure time	6 h

FIG. 13 Comparison of effect of gas velocity on fouling layer thermal resistance between model and experiment for (a) 30 m/s; (b) 70 m/s; and (c) 120 m/s.

TABLE 5 Comparison of deposit layer thickness

Gas velocity (m/s)	Experiment (mm)	Model (mm)
30	1.0	0.87
70	0.42	0.33
120	–	0.13

TABLE 6 Effect of deposit layer thermal conductivity

Deposit thermal conductivity (W/mK)	Total mass gain (mg)	% Difference
0.03	42.2	12.2
0.05	48.1	–
0.07	52.6	9.5
0.1	58.6	21.9

FIG. 14 Effect of deposit thermal conductivity on total deposit mass calculated by the model as a function of time.

TABLE 7 Effect of deposit layer density

Deposit density (kg/m^3)	Total mass gain (mg)	% Difference
20	40.2	16.5
35	48.1	–
50	54.1	12.6

FIG. 15 Effect of deposit density on total deposit mass calculated by the model as a function of time.

Abd-Elhady , M. S. , Zornek , T. , Malayeri , M. R. , Balestrino , S. , Szymkowicz , P. G. and Müller-Steinhagen , H. 2010 . Influence of Gas Velocity on Particulate Fouling of Exhaust Gas Recirculation Coolers . Int. J. Heat Mass Tran. , 54 ( 4 ) : 838 – 846 .

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