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Pressure drop accross parallel plates flowing into vacuum

Pressure drop accross parallel plates flowing into vacuum

Pressure drop accross parallel plates flowing into vacuum

(OP)
I need help calculating the pressure drop accross two flat plates that are .042" apart, 2" long and 4" deep. The channel has a constant vapor injection along the walls as shown via a semi permeable membrane (drawn in blue) and rejections the vapor to vacuum as shown. I've thought about simplifying the problem by just using either 1/2 or 1/3 the average mass flow rate through the full channel, but I am not sure that is a good approximation (I somewhat remember solving this problem many years ago and finding that to be the solution). In any case, I am having trouble even calculating the reynolds number without knowing the bulk velocity. I know at the outlet the full mass flow rate is 3.26 mg/s but I am not sure at what pressure. I know on the inside of the permeable membrane I am at saturation conditions (9 degrees C) so approximately 8.6 torr (1147 PA, .16647 psi) but thats about it. I keep going in circles trying to solve for the pressure/temperature/reynolds number/pressure drop once in the channel. Any ideas?

RE: Pressure drop accross parallel plates flowing into vacuum

Some things are just better done, or only possible by full scale, or scale testing. You can't solve for all variables without a sufficient number of equations, or any boundry conditions.

Independent events are seldomly independent.

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