4.3 Experiment-1 DPM model validation

Table 3 shows the compared results of base case simulations and field experiments at 1, 5 and 10 m downstream of the vehicle and at the sample point a, b and c. The simulated results were in fair agreement with the measured data at a number of instances and such results which slightly deviated from the measured data can be due uneven gallery walls surface were not considered while modeling. The difference varies from 14.2 to +14%.

#### 4.4 DPM exposure levels for passenger during vehicle movement

DPM concentration was measured in the passenger seat during vehicle movement. The vehicle engine was assumed to run at full capacity so that the engine

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

emitted maximum amount of fumes. DPM measurements were recorded as the vehicle traveled from the pit bottom to the work place, a distance of 4 km. The maximum speed of the vehicle on level ground is 25 km/h. During the experiment, the average velocity of the vehicle was 10 km/h (2.7 m/s). Figure 10 shows the DPM concentration at different time periods during 4 km travel distance. The concentration changes with relative velocities between vehicle and air.

#### 4.5 Changes of DPM concentration with intake air velocity

To understand the effect of intake air velocity on DPM dispersion, simulation studies were conducted with the air velocity ranging from 0.5 to 3 m/s.

Figure 11 shows the DPM concentration in the vertical mid-plane of the mine gallery when the intake air velocity is 0.5 m/s. The results show that high DPM concentration of over 200 μg/m<sup>3</sup> is observed in almost the entire roadway. High DPM concentration is also observed on the passenger side of the vehicle. Downstream of the vehicle, high DPM concentration spreads across almost the entire cross-section of the roadway.

Figure 12 shows the DPM concentration corresponding to an intake air velocity 3 m/s. most of the DPM concentration is at the smoke pipe side of the gallery roof

Figure 10.

EC concentration at passenger seat (moving vehicle).

#### Figure 11.

DPM distribution with 0.5 m/s air velocity, center section of the mine gallery. (a) DPM concentration at mine gallery. (b) DPM concentration in vertical mid-plane of the gallery.

Figure 12.

DPM distribution with 3 m/s air velocity, top and center section view of mine gallery. (a) DPM concentration at mine gallery, top view. (b) DPM concentration in vertical mid-plane of the gallery.

due to high air velocity. Negligible DPM concentration was observed at the middle of the roadway up to 20 m downstream of the vehicle. Beyond 20 m downstream of the vehicle, DPM concentration of 60 μg/m<sup>3</sup> is observed near the ceiling and concentration reduced to zero towards the floor.
