The flow of butane and isobutane vapors near saturation through porous Vycor glass membranes

Large mass flux differences for opposite flow directions of a condensable gas through an asymmetric porous membrane

“…The system of governing equation was also presented in Ref. [11]. For the one-dimensional flow considered here, the mass balance simply states that the mass flux J is constant…”

“…For instance, measurements on the permeation of nitrogen through Vycor glass membranes yielded values between 3.8 and 9.5 for β, see Table 1 in Ref. [11].…”

“…The flow of a fluid through a porous membrane if capillary condensation occurs was described by a number of authors [4][5][6][7][8][9][10][11]. Usually, the energy balance was neglected and isothermal flow was assumed [5][6][7][8][9].…”

“…Condensation due to the Joule-Thomson effect was initially investigated neglecting capillary condensation [12][13][14]. Later, the flow through homogeneous porous membranes was described, accounting both for capillary condensation and the Joule-Thomson effect [10,11].…”

“…Also, in cases in which condensation due to capillary condensation would not be possible, e.g., for non-wetting membranes, the heat transfer due to the Joule-Thomson effect could cause condensation of the fluid [15]. Quantitatively, the description of the flow accounting for capillary condensation, but not the Joule-Thomson effect, i.e., an isothermal description, could yield mass fluxes which were an order of magnitude larger than the adiabatic, non-isothermal description accounting for the Joule-Thomson effect [10,11].…”