6.2.3 Effect of Temperature on Cavitation Effect
The transient cavitation is directly affected by the system temperature. As the system
temperature increases, the effect of cavitation is also reduced as shown in Table 6.3;
thus, the formation of reactive species is also reduced which can be elucidated based
on the initial diameter of the cavitation bubbles as discussed in the previous section.
Table 6.3 Summary of equilibrium composition and bubble condition at different temperatures
(T o ) (Chakma and Moholkar 2013b)
Properties of bubble at different temperatures
T ¼ 283 K
T ¼ 303 K
T ¼ 323 K
T ¼ 343 K
Conditions at the first collapse of cavitation bubble
T max ¼ 3989 K
T max ¼ 3999 K
T max ¼ 3733 K
T max ¼ 2683 K
P max ¼ 681.5 MPa P max ¼ 696.7 MPa P max ¼ 623.9 MPa P max ¼ 175.3 MPa
V turb ¼ 0.35 m/s
V turb ¼ 0.36 m/s
V turb ¼ 0.45 m/s
V turb ¼ 1.08 m/s
P AW ¼ 24.75 MPa P AW ¼ 24.04 MPa P AW ¼ 21.56 MPa P AW ¼ 4.43 MPa
N N2 ¼ 1.38 Â 10
10
N N2 ¼ 1.28 Â 10
10
N N2 ¼ 1.21 Â 10
10
N N2 ¼ 1.13 Â 10
10
N O2 ¼ 3.66 Â 10
9
N O2 ¼ 3.41 Â 10
9
N O2 ¼ 3.20 Â 10
9
N O2 ¼ 3.02 Â 10
9
N W ¼ 7.94 Â 10
8
N W ¼ 2.91 Â 10
9
N W ¼ 1.23 Â 10
10
N W ¼ 8.15 Â 10
10
Species Equilibrium composition
283 K
303 K
323 K
343 K
N 2
7.07 Â 10
À1
6.26 Â 10
À1
4.13 Â 10
À1
1.16 Â 10
À1
O 2
1.45 Â 10
À1
1.28 Â 10
À1
8.84 Â 10
À2
2.83 Â 10
À2
H 2 O
1.63 Â 10
À2
1.41 Â 10
À2
1.21 Â 10
À2
2.80 Â 10
À2
N
1.72 Â 10
À5
1.56 Â 10
À5
3.84 Â 10
À6
–
O
6.67 Â 10
À3
5.95 Â 10
À3
2.44 Â 10
À3
5.69 Â 10
À5
H
3.21 Â 10
À4
2.83 Â 10
À4
1.06 Â 10
À4
2.57 Â 10
À6
O 3
1.89 Â 10
À5
1.70 Â 10
À5
8.38 Â 10
À6
2.28 Â 10
À7
H 2
2.91 Â 10
À4
2.53 Â 10
À4
1.30 Â 10
À4
2.29 Â 10
À5
OH
1.08 Â 10
À2
9.51 Â 10
À3
5.27 Â 10
À3
8.08 Â 10
À4
HO 2
6.31 Â 10
À4
5.59 Â 10
À4
3.25 Â 10
À4
4.22 Â 10
À5
H 2 O 2
2.28 Â 10
À5
2.00 Â 10
À5
1.36 Â 10
À5
4.60 Â 10
À6
NO
9.51 Â 10
À2
8.47 Â 10
À2
4.72 Â 10
À2
4.57 Â 10
À3
NO 2
1.90 Â 10
À3
1.70 Â 10
À3
1.04 Â 10
À3
1.11 Â 10
À4
N 2 O
4.01 Â 10
À4
3.61 Â 10
À4
1.88 Â 10
À4
8.69 Â 10
À6
NH
1.89 Â 10
À6
1.70 Â 10
À6
–
–
HNO
6.67 Â 10
À5
5.95 Â 10
À5
2.74 Â 10
À5
9.69 Â 10
À7
HNO 2
1.96 Â 10
À4
1.75 Â 10
À4
1.12 Â 10
À4
1.76 Â 10
À5
Note: N W number of water molecules trapped in the bubble, N N2 number of N 2 molecules in the
bubble, N O2 number of oxygen molecules in the cavitation bubble, P o ambient pressure in liquid
medium, P max pressure peak attained inside the bubble during first collapse, P AW acoustic wave
pressure amplitude induced during cavitation, T cavitation bubbles’ temperature, T o ambient
temperature or liquid temperature, T max temperature peak attained inside the bubble during first
collapse, V turb average velocity of micro-turbulence in the liquid medium generated by ultrasound
and cavitation (estimated at 1 mm distance from bubble center)
6 Degradation Mechanism of Pollutants Using Sono-hybrid Advanced Oxidation. . .
197
The transient cavitation is directly affected by the system temperature. As the system
temperature increases, the effect of cavitation is also reduced as shown in Table 6.3;
thus, the formation of reactive species is also reduced which can be elucidated based
on the initial diameter of the cavitation bubbles as discussed in the previous section.
Table 6.3 Summary of equilibrium composition and bubble condition at different temperatures
(T o ) (Chakma and Moholkar 2013b)
Properties of bubble at different temperatures
T ¼ 283 K
T ¼ 303 K
T ¼ 323 K
T ¼ 343 K
Conditions at the first collapse of cavitation bubble
T max ¼ 3989 K
T max ¼ 3999 K
T max ¼ 3733 K
T max ¼ 2683 K
P max ¼ 681.5 MPa P max ¼ 696.7 MPa P max ¼ 623.9 MPa P max ¼ 175.3 MPa
V turb ¼ 0.35 m/s
V turb ¼ 0.36 m/s
V turb ¼ 0.45 m/s
V turb ¼ 1.08 m/s
P AW ¼ 24.75 MPa P AW ¼ 24.04 MPa P AW ¼ 21.56 MPa P AW ¼ 4.43 MPa
N N2 ¼ 1.38 Â 10
10
N N2 ¼ 1.28 Â 10
10
N N2 ¼ 1.21 Â 10
10
N N2 ¼ 1.13 Â 10
10
N O2 ¼ 3.66 Â 10
9
N O2 ¼ 3.41 Â 10
9
N O2 ¼ 3.20 Â 10
9
N O2 ¼ 3.02 Â 10
9
N W ¼ 7.94 Â 10
8
N W ¼ 2.91 Â 10
9
N W ¼ 1.23 Â 10
10
N W ¼ 8.15 Â 10
10
Species Equilibrium composition
283 K
303 K
323 K
343 K
N 2
7.07 Â 10
À1
6.26 Â 10
À1
4.13 Â 10
À1
1.16 Â 10
À1
O 2
1.45 Â 10
À1
1.28 Â 10
À1
8.84 Â 10
À2
2.83 Â 10
À2
H 2 O
1.63 Â 10
À2
1.41 Â 10
À2
1.21 Â 10
À2
2.80 Â 10
À2
N
1.72 Â 10
À5
1.56 Â 10
À5
3.84 Â 10
À6
–
O
6.67 Â 10
À3
5.95 Â 10
À3
2.44 Â 10
À3
5.69 Â 10
À5
H
3.21 Â 10
À4
2.83 Â 10
À4
1.06 Â 10
À4
2.57 Â 10
À6
O 3
1.89 Â 10
À5
1.70 Â 10
À5
8.38 Â 10
À6
2.28 Â 10
À7
H 2
2.91 Â 10
À4
2.53 Â 10
À4
1.30 Â 10
À4
2.29 Â 10
À5
OH
1.08 Â 10
À2
9.51 Â 10
À3
5.27 Â 10
À3
8.08 Â 10
À4
HO 2
6.31 Â 10
À4
5.59 Â 10
À4
3.25 Â 10
À4
4.22 Â 10
À5
H 2 O 2
2.28 Â 10
À5
2.00 Â 10
À5
1.36 Â 10
À5
4.60 Â 10
À6
NO
9.51 Â 10
À2
8.47 Â 10
À2
4.72 Â 10
À2
4.57 Â 10
À3
NO 2
1.90 Â 10
À3
1.70 Â 10
À3
1.04 Â 10
À3
1.11 Â 10
À4
N 2 O
4.01 Â 10
À4
3.61 Â 10
À4
1.88 Â 10
À4
8.69 Â 10
À6
NH
1.89 Â 10
À6
1.70 Â 10
À6
–
–
HNO
6.67 Â 10
À5
5.95 Â 10
À5
2.74 Â 10
À5
9.69 Â 10
À7
HNO 2
1.96 Â 10
À4
1.75 Â 10
À4
1.12 Â 10
À4
1.76 Â 10
À5
Note: N W number of water molecules trapped in the bubble, N N2 number of N 2 molecules in the
bubble, N O2 number of oxygen molecules in the cavitation bubble, P o ambient pressure in liquid
medium, P max pressure peak attained inside the bubble during first collapse, P AW acoustic wave
pressure amplitude induced during cavitation, T cavitation bubbles’ temperature, T o ambient
temperature or liquid temperature, T max temperature peak attained inside the bubble during first
collapse, V turb average velocity of micro-turbulence in the liquid medium generated by ultrasound
and cavitation (estimated at 1 mm distance from bubble center)
6 Degradation Mechanism of Pollutants Using Sono-hybrid Advanced Oxidation. . .
197