Roman and Greek Symbols (SI)
${\alpha }_i$	Constants
$A_w$	Solvent permeability constant, $[{\mathrm{m}}^2 \mathrm{s}/\mathrm{K}\mathrm{g}]$
$B_s$	Solute permeability constant, $\left[\mathrm{m}/\mathrm{s}\right]$
$C$	Concentration, $\left[\mathrm{K}\mathrm{g}/{\mathrm{m}}^3\right]$
$J_s$	Solute flux, $\left[\mathrm{K}\mathrm{g}/{\mathrm{m}}^2 \mathrm{s}\right]$
$J_w$	Solvent flux, $\left[{\mathrm{m}}^3/{\mathrm{m}}^2 \mathrm{s}\right]$
$n$	Molar concentration, $[\mathrm{Moles}/{\mathrm{m}}^3$]
$u$	Feed velocity, $\left[\mathrm{m}/\mathrm{s}\right]$
$d_h$	Hydraulic diameter, $\left[\mathrm{m}\right]$
$Re$	Reynolds number
$Sc$	Schmidt number
$Sh$	Sherwood number
$k$	Mass transfer coefficient, $\left[\mathrm{m}/\mathrm{s}\right]$
$\Delta P$	Applied pressure, $[\mathrm{K}\mathrm{g}/{\mathrm{s}}^2 \mathrm{m}]$
$Q$	Feed flowrate, $\left[{\mathrm{m}}^3/\mathrm{s}\right]$
$R$	Universal gas constant, $\left[\mathrm{K}\mathrm{g} {\mathrm{m}}^2/{\mathrm{s}}^2 \mathrm{K}\right]$
$S$	Membrane surface area, $\left[{\mathrm{m}}^2\right]$
$t$	Time, $\left[\mathrm{s}\right]$
$T$	Temperature absolute, $\left[\mathrm{K}\right]$
$V$	Volume, $\left[{\mathrm{m}}^3\right]$
$X$	Batch recovery rate
$\pi$	Osmotic pressure, $\left[\mathrm{K}\mathrm{g}/{\mathrm{s}}^2 \mathrm{m}\right]$
$\psi$	Osmotic pressure to solute concentration ratio, $[{\mathrm{m}}^2/{\mathrm{s}}^2]$
$\Delta L$	Head loss, $\left[\mathrm{K}\mathrm{g}/{\mathrm{s}}^2 \mathrm{m}\right]$
Subscripts
$f$	Feed
$f0$	Feed at time = 0
$p$	Permeate
$pav$	Produced average permeate
$r$	Recycled
$m$	Membrane wall