temperature peak was 3999 K, thus water molecules dissociated and formed radicals.
As the static pressure increases, the cavitation effect also reduces that results in
lowest temperature peak (~313 K), leading to no production of
•
OH radicals.
Table 6.2 Effect of static pressure (P o ) on sonochemical process for production of radicals and
other species (Chakma and Moholkar 2013b)
Conditions at the first collapse of the bubble
P o ¼ 100 kPa
P o ¼ 120 kPa
P o ¼ 150 kPa
P o ¼ 200 kPa
T max ¼ 3999 K
T max ¼ 3024 K
T max ¼ 977.3 K
T max ¼ 353.4 K
P max ¼ 696.7 MPa P max ¼ 286.3 MPa P max ¼ 4.62 MPa
P max ¼ 416 kPa
V turb ¼ 0.36 m/s
V turb ¼ 0.21 m/s
V turb ¼ 0.07 m/s
V turb ¼ 0.008 m/s
P AW ¼ 24.04 MPa P AW ¼ 5.43 MPa
P AW ¼ 120 kPa
P AW ¼ 2 kPa
N N2 ¼ 1.28 Â 10
10
N N2 ¼ 1.48 Â 10
10
N N2 ¼ 1.78 Â 10
10
N N2 ¼ 2.28 Â 10
10
N O2 ¼ 3.41 Â 10
9
N O2 ¼ 3.95 Â 10
9
N O2 ¼ 4.74 Â 10
9
N O2 ¼ 6.07 Â 10
9
N W ¼ 2.91 Â 10
9
N W ¼ 1.81 Â 10
9
N W ¼ 8.86 Â 10
8
N W ¼ 8.19 Â 10
10
Species Equilibrium composition
P o ¼ 100 kPa
P o ¼ 120 kPa
P o ¼ 150 kPa
P o ¼ 200 kPa
N 2
6.26 Â 10
À1
6.99 Â 10
À1
7.60 Â 10
À1
7.68 Â 10
À1
O 2
1.28 Â 10
À1
1.67 Â 10
À1
2.02 Â 10
À1
2.04 Â 10
À1
H 2 O
1.41 Â 10
À2
7.45 Â 10
À2
3.80 Â 10
À2
2.80 Â 10
À2
N
1.56 Â 10
À5
–
–
–
O
5.95 Â 10
À3
9.35 Â 10
À4
–
–
H
2.83 Â 10
À4
4.09 Â 10
À5
–
–
O 3
1.70 Â 10
À5
3.71 Â 10
À6
–
–
H 2
2.53 Â 10
À4
1.67 Â 10
À4
–
–
OH
9.51 Â 10
À3
6.33 Â 10
À3
–
–
HOO
•
5.59 Â 10
À4
3.60 Â 10
À4
–
–
H 2 O 2
2.00 Â 10
À5
2.74 Â 10
À5
–
–
NO
8.47 Â 10
À2
4.30 Â 10
À2
2.64 Â 10
À5
–
NO 2
1.70 Â 10
À3
1.03 Â 10
À3
1.09 Â 10
À5
–
N 2 O
3.61 Â 10
À4
1.10 Â 10
À4
–
–
NH
1.70 Â 10
À6
–
–
–
HNO
5.95 Â 10
À5
1.38 Â 10
À5
–
–
HNO 2
1.75 Â 10
À4
1.40 Â 10
À4
–
–
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)
196
S. Chakma et al.
As the static pressure increases, the cavitation effect also reduces that results in
lowest temperature peak (~313 K), leading to no production of
•
OH radicals.
Table 6.2 Effect of static pressure (P o ) on sonochemical process for production of radicals and
other species (Chakma and Moholkar 2013b)
Conditions at the first collapse of the bubble
P o ¼ 100 kPa
P o ¼ 120 kPa
P o ¼ 150 kPa
P o ¼ 200 kPa
T max ¼ 3999 K
T max ¼ 3024 K
T max ¼ 977.3 K
T max ¼ 353.4 K
P max ¼ 696.7 MPa P max ¼ 286.3 MPa P max ¼ 4.62 MPa
P max ¼ 416 kPa
V turb ¼ 0.36 m/s
V turb ¼ 0.21 m/s
V turb ¼ 0.07 m/s
V turb ¼ 0.008 m/s
P AW ¼ 24.04 MPa P AW ¼ 5.43 MPa
P AW ¼ 120 kPa
P AW ¼ 2 kPa
N N2 ¼ 1.28 Â 10
10
N N2 ¼ 1.48 Â 10
10
N N2 ¼ 1.78 Â 10
10
N N2 ¼ 2.28 Â 10
10
N O2 ¼ 3.41 Â 10
9
N O2 ¼ 3.95 Â 10
9
N O2 ¼ 4.74 Â 10
9
N O2 ¼ 6.07 Â 10
9
N W ¼ 2.91 Â 10
9
N W ¼ 1.81 Â 10
9
N W ¼ 8.86 Â 10
8
N W ¼ 8.19 Â 10
10
Species Equilibrium composition
P o ¼ 100 kPa
P o ¼ 120 kPa
P o ¼ 150 kPa
P o ¼ 200 kPa
N 2
6.26 Â 10
À1
6.99 Â 10
À1
7.60 Â 10
À1
7.68 Â 10
À1
O 2
1.28 Â 10
À1
1.67 Â 10
À1
2.02 Â 10
À1
2.04 Â 10
À1
H 2 O
1.41 Â 10
À2
7.45 Â 10
À2
3.80 Â 10
À2
2.80 Â 10
À2
N
1.56 Â 10
À5
–
–
–
O
5.95 Â 10
À3
9.35 Â 10
À4
–
–
H
2.83 Â 10
À4
4.09 Â 10
À5
–
–
O 3
1.70 Â 10
À5
3.71 Â 10
À6
–
–
H 2
2.53 Â 10
À4
1.67 Â 10
À4
–
–
OH
9.51 Â 10
À3
6.33 Â 10
À3
–
–
HOO
•
5.59 Â 10
À4
3.60 Â 10
À4
–
–
H 2 O 2
2.00 Â 10
À5
2.74 Â 10
À5
–
–
NO
8.47 Â 10
À2
4.30 Â 10
À2
2.64 Â 10
À5
–
NO 2
1.70 Â 10
À3
1.03 Â 10
À3
1.09 Â 10
À5
–
N 2 O
3.61 Â 10
À4
1.10 Â 10
À4
–
–
NH
1.70 Â 10
À6
–
–
–
HNO
5.95 Â 10
À5
1.38 Â 10
À5
–
–
HNO 2
1.75 Â 10
À4
1.40 Â 10
À4
–
–
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)
196
S. Chakma et al.