| A |
Membrane area: m2
|
Sh |
Sherwood number, dimensionless |
| Ad
|
Membrane area in cell, m2
|
Sc |
Schmidt number, dimensionless |
| Cb
|
Bulk concentration, kgm−3
|
Pe |
Peclet number, dimensionless |
| CCL
|
Boundary layer concentration, kgm−3
|
Wd
|
Stability factor with respect to deposition (parameter in No. 4.4, Table 4) |
| Cg
|
Gel concentration, kgm−3
|
s |
Sedimentation coefficient |
| Cgv
|
Concentration gel layer in volume, m3
|
t |
Time, s |
| Cm
|
Intrinsic concentration, kgm−3
|
tR
|
Fouling phase time, s |
| Cp
|
Permeated concentration, kgm−3
|
τ |
Tortuosity, dimensionless |
| C0v
|
Feed concentration, kgm−3
|
T |
Temperature, °C |
| Dm
|
Equivalent diffusion diameter of macromolecules (parameter in No. 1.11), m |
U |
Flow velocity, ms−1
|
| D |
Diffusivity, m2s−1
|
U0
|
Initial flow velocity, ms−1
|
| d |
Diameter of the module, m |
v(L)
|
Average permeate velocity on the length of the filter channel, ms−1
|
| dh
|
Hydraulic diameter, m |
vf
|
Local filtrate velocity (parameter No. 1.8), ms−1
|
| dp
|
Pore diameter, m |
X(t) |
Position change of the equilibrium zone (parameter in No. 4.5) |
| F |
Intermolecular interactions |
b |
Radius of the stirred cell (parameter of No. 1.8) |
| fc
|
Marchetti correction factor |
V |
Permeate volume (parameter in No. 3.10), L |
| fcp
|
Capilar effect |
Vc
|
Permeate volume at the reference time point (parameter in No. 3.10), L |
| b |
Inverse of the solute density (parameter of No. 1.9) |
V |
Permeate volume, m3
|
| H |
Height of liquid over membrane (parameter of No. 1.9), m |
V0
|
Initial permeate volume, m3
|
| η |
Non-dimensional distance (parameter of No. 1.9) = x/H |
v |
Specific partial volume, kgm3
|
| ϕ |
Non-dimensional concentration (parameter of No. 1.9) = c/co |
v0
|
Specific partial initial volume, kgm3
|
| fd
|
Dipole effect |
VRF |
Volume reduction factor, dimensionless |
| fe
|
Steric effect |
v |
Kinematic viscosity, m2s−1
|
| H |
Thickness of the gel layer, m |
xi
|
Proportional parameter of permeability in No. 1.3 |
| J |
Permeate flux, ms−1
|
∆x |
Membrane thickness, m |
| Jf
|
Final permeate flux, ms−1
|
X12
|
Flory-Huggins parameter |
| Jlim
|
Limit permeate flux, ms−1
|
z* |
Axial position for osmotic pressure, m |
| J∞
|
Saturation (equilibrium) volumetric permeate flux, m3m−2s−1
|
|
|
| Jss
|
Steady-state permeate flux, ms−1
|
Greek symbols |
| JW
|
Flux of pure water permeate, ms−1
|
δ |
Thickness of the boundary layer, m |
| J* |
Hydraulic lifting speed, ms−1
|
∆π |
Osmotic pressure, Pa |
| Jo
|
Balance between solute input and output, |
γ |
Shear rate, ms−1
|
| k |
Mass transfer coefficient, ms−1
|
γm |
Shear rate at the wall (parameter in No. 1.11), s−1
|
| ko
|
Ideal mass transfer coefficient, ms−1
|
Ɛ |
Porosity of the membrane, dimensionless |
| K |
Boltzmann constant (parameter in No. 1.11), Jmol−1K−1
|
α |
Specific resistance of the deposit on membrane, kgm2
|
| L |
Length of the module, m |
ϵ |
Specific gel resistance, m−2
|
| Lp
|
Membrane permeability, mPa−1s−1
|
ƐCL
|
Boundary layer porosity, dimensionless |
| Lph
|
Effective permeability reverse flow, |
β |
Parameter of No. 1.5 |
| mp
|
Deposited cake weight, kg |
σ |
Reflection coefficient |
| MW |
Membrane cut-off limit, gmol−1
|
Ɛg
|
Solidity of the gel layer, % |
| ∆P |
Transmembrane pressure, Pa |
εst
|
Steady-state value of the average solidity, % |
| Q |
Flow rate, m3s−1
|
μ0
|
Initial viscosity, Pa s |
| Rm
|
Membrane resistance, m−1
|
μb
|
Viscosity in the bulk, Pa s |
| RM
|
Fouled membrane resistance, m−1
|
μ |
Viscosity, Pa s |
| Rad,ss
|
Adsorption resistance, m−1
|
ρ |
Feed density, kgm−3
|
| Rcp
|
Concentration polarization resistance, m−1
|
ρpol
|
Membrane polymer density, kgm−3
|
| Rcp,ss
|
Steady-state concentration polarization resistance, m−1
|
γa
|
Axial speed, ms−1
|
| Re |
Reynolds number, dimensionless |
υpo
|
Osmotic pressure limiting flux (m3 m−2 s−1) |
| Rf
|
Irreversible resistance, m−1
|
X12
|
Flory–Huggins interaction parameter |
| Rg
|
Gel resistance, m−1
|
ϕ |
Volume fraction of particles at the distance x from the membrane surface |
| Rm
|
Hydraulic resistance, m−1
|
ϕ |
1/Jlim (parameter of No. 3.11), m2sm−3
|
|
|
Experimental resistance (constant ΔP), m−1
|
|
|
| Rm i−1
|
Accumulated resistance at ti−1, |
|
|
|
|
Concentration polarization differential resistance, dimensionless |
|
|
| Rt
|
Total resistance, m−1
|
|
|
| rCL
|
Specific resistance of the boundary layer, m−1
|
|
|
| ri
|
Cell radius, m |
|
|
| ro
|
Initial cell radius, m |
|
|
| rp
|
Particle radius, m |
|
|
| rpp
|
Membrane pore radius, m |
|
|