Page 27 - Air pollution and greenhouse gases from basic concepts to engineering applications for air emission control

xxviii Nomenclature
2
Δγ Specific adhesion energy (J/m )
Relative permittivity of the fiber (–)
ε r
Relative permittivity or dielectric constant of the particle with respect to
ε r
vacuum (–)
−12
ε 0 Permittivity of a vacuum, 8.854 × 10 (C/V m)
Particle adhesion efficiency (–)
η ad
Single fiber efficiency by diffusion (–)
η D
Single fiber efficiency by impaction (–)
η ip
Single fiber filtration by interception (–)
η it
Sampling efficiency (–)
η s
Single granule efficiency (–)
η sG
Total efficiency of a single fiber (–)
η sf
Particle transport efficiency (–)
η ts
Separation efficiency for particles (–)
η p
Breakthrough efficiency in adsorption (–)
η x
θ Angle (rad)
λ Mean free path of gas (m)
2
μ Kinetic (Dynamic) viscosity (Pa s, N s/m )
ρ Density (kg/m )
3
3
Density of the surrounding air (kg/m )
ρ a
3
Bulk density of the adsorbent (kg/m )
ρ b
3
Ground level air density (kg/m )
ρ 0
3
Density of the air parcel (kg/m )
ρ p
3
Particle density (kg/m )
ρ p
Reaction rate ratio (–)
ρ r
σ g Geometric standard deviation (–)
σ y Dispersion coefficient in the transverse (y) direction (m)
σ z Dispersion coefficient in the vertical (z) direction (m)
τ Characteristic time for aerodynamic particle settling (s)
τ Half-value time in aerosol coagulation (s)
2
τ Shear stress (N/m )
The ground level (surface) shear stress (m)
τ 0
U Equivalence ratio in combustion (–)
U Latitude where the air is of concern (–)
Ø(u) Cumulative probability function (–)
Ω Angular speed of the earth, 7.25 × 10 −5 rad/s
3
[i] Mole concentration (mol/m )