5. Results and discussions—experiment 2

#### 5.1 DPM and air flow in opposite directions

Figure 13 shows the results of CFD simulations in isometric view when DPM and air flow are in opposite directions (counter-flow). Near the LHD, it can be observed that high DPM concentration is at middle of the gallery and above the LHD. At downstream side of the LHD, DPM particles spreads throughout the gallery, with the maximum concentration is in the middle and at sides of the gallery.

Figure 14 shows the DPM concentration patterns at 2, 5 and 8 m downstream of the vehicle rear end. Figure 14(a) shows the high DPM concentration near the top and bottom portions of the vehicle. Figure 14(b) shows the maximum

Figure 13. DPM flow pattern—isometric view.

Analysis of Diesel Particulate Matter Flow Patterns in Different Ventilation and Operational… DOI: http://dx.doi.org/10.5772/intechopen.84651

concentration is at top and bottom portions of the vehicle, concentrations also spreads at left and right sides of the road ways. DPM concentration at LHD operator is 125 μg/m<sup>3</sup> . Figure 14(c) shows the DPM flow moved towards the roof and bottom of the road way, DPM concentration spreads at towards left and right sides of the road way.

Figure 15 shows the DPM concentration field at 6, 10 and 20 m downstream of the vehicle. Figure 15(a) shows the DPM concentration at 6 m downstream of the vehicle. Here, high DPM concentration is observed near the floor of the roadway, and the concentrations gradually reduces towards the roof.

Figure 14.

DPM concentration at 2, 5 and 10 m downstream of the vehicle. (a) DPM concentration at 2 m downstream of the smoke pipe. (b) DPM concentration at 5 m downstream of the smoke pipe. (c) DPM concentration at 8 m downstream of the smoke pipe.

DPM concentration at 2, 5 and 10 m downstream of the vehicle. (a) DPM concentration at 6 m downstream of the vehicle. (b) DPM concentration at 10 m downstream of the vehicle. (c) DPM concentration at 20 m downstream of the vehicle.

Figure 15(b) shows the DPM concentration field at 10 m downstream of the vehicle. Here, the maximum concentration is at middle of the gallery and left and right sides of the road ways.

Figure 15(c) shows the DPM concentration field at 20 m downstream of the vehicle. Here, the DPM is found to spread throughout the entire roadway. The DPM concentration at the center of the road way is 34 μg/m<sup>3</sup> and similar concentrations observed at left and right sides of the road way.
