Page 63 - Dust Explosions in the Process Industries

36 Dust Explosions in the Process Industries

6

2e 200 - /i-
-

L - x
c Figure 1.36 Influence of nominal dust concen-
P 100 - !
% // tration in a Hartmann bomb on maximum explo-
I
f sion pressure and maximum rate of pressure rise.
0 / I I I Maize starch containing 1 1 % moisture. The bars

1.0 ,

0 100 200 300 400 500 600 700 800
ESTIMATED AVERAGE DUST CONCENTRATION lg/rn31

Figure 1.37 Influence of estimatedaverage dust concentration in exploding cloud in 236 m3silo of
L/D = 6, on maximum explosion pressure in vented silo. Vent area at the top of the silo is 5.7 m2.
Maize starch contains 1 I % moisture. Ignition is close to the bottom of the silo (From Eckhoff et al.,
1985).

1.3.5
TURBULENCE

In practical terms, turbulence in the present context is a state of rapid internal, more or
less random movement of small elements of the dust cloud relative to each other in
three dimensions. If the cloud is burning, turbulence gives rise to mixing of the hot