Study on the effect of ash layer on flow and heat transfer in DPF based on three-dimensional thermal lattice Boltzmann method

After the diesel engine works for a long time, dense ash layer will be formed

on the diesel particulate filter (DPF) surface, which will increase the back

pressure on the DPF surface and seriously affect the normal operation of the

DPF. The DPF micro-structure is generated by 3D reconstruction technology.

Moreover, the particle layer and ash layer are reconstructed by Quartet

Structure Generation Set. The exhaust gas with a velocity of 0.05 m/s~0.25

m/s is introduced into the DPF model. Under the condition of 873 K

temperature field, the 3D lattice Boltzmann method is used to explore the

influence of the particle layer and ash layer accumulated in its

micro-structure on its flow and heat transfer. The results show that with

the accumulation of ash, the flow velocity in the DPF increases with the

decrease of porosity. The existence of ash layer increases the pressure

difference between the inlet and outlet of the structure, and the pressure

difference between the inlet and outlet of the structure increases with the

increase of the air inlet speed. Under the same flow conditions, the heat

transfer process of structures containing ash stratification is faster, and

the highest temperature point moves forward accordingly. This has certain

guiding significance for exploring the thermal load of ash containing DPF

structure.